U.S. patent application number 11/679358 was filed with the patent office on 2008-08-28 for injection molding nozzle assembly with composite nozzle tip.
This patent application is currently assigned to HUSKY INJECTION MOLDING SYSTEMS LTD.. Invention is credited to Abdeslam BOUTI, Thomas Andrew LAWRENCE.
Application Number | 20080206391 11/679358 |
Document ID | / |
Family ID | 39720803 |
Filed Date | 2008-08-28 |
United States Patent
Application |
20080206391 |
Kind Code |
A1 |
BOUTI; Abdeslam ; et
al. |
August 28, 2008 |
Injection Molding Nozzle Assembly with Composite Nozzle Tip
Abstract
A nozzle assembly for an injection molding assembly has a nozzle
housing having a melt channel extending therethrough, a nozzle tip,
and a retainer that retains the nozzle tip against the nozzle
housing. The nozzle tip is formed of a precipitation hardened, high
thermal conductivity material and a precipitation hardened, high
strength material, which are integrally joined together to form the
body. The thermal conductivity of the high thermal conductivity
material is greater than the thermal conductivity of the high
strength material, and the strength of the high strength material
is greater than the strength of the high thermal conductivity
material. The high thermal conductivity material and the high
strength material can be precipitation hardened together under the
same precipitation hardening conditions to achieve increases in the
value of at least one strength aspect of the high thermal
conductivity material and the value of at least one strength aspect
of the high strength material.
Inventors: |
BOUTI; Abdeslam; (Swanton,
VT) ; LAWRENCE; Thomas Andrew; (Burlington,
VT) |
Correspondence
Address: |
HUSKY INJECTION MOLDING SYSTEMS, LTD;CO/AMC INTELLECTUAL PROPERTY GRP
500 QUEEN ST. SOUTH
BOLTON
ON
L7E 5S5
omitted
|
Assignee: |
HUSKY INJECTION MOLDING SYSTEMS
LTD.
Bolton
CA
|
Family ID: |
39720803 |
Appl. No.: |
11/679358 |
Filed: |
February 27, 2007 |
Current U.S.
Class: |
425/542 |
Current CPC
Class: |
C21D 9/00 20130101; B29C
2045/2787 20130101; B29C 45/278 20130101; B29C 2045/2783 20130101;
C22C 9/06 20130101; B29C 2045/2785 20130101 |
Class at
Publication: |
425/542 |
International
Class: |
B29C 45/20 20060101
B29C045/20 |
Claims
1. A nozzle assembly for an injection molding runner system,
comprising: a nozzle housing having a melt channel therethrough; a
nozzle tip comprising a body having a bore extending therethrough,
the body formed of materials comprising a precipitation hardened,
high thermal conductivity material and a precipitation hardened,
high strength material, wherein: the high thermal conductivity
material and the high strength material are integrally joined
together to form the body, the thermal conductivity of the high
thermal conductivity material is greater than the thermal
conductivity of the high strength material, at least one strength
aspect of the high strength material has a value greater than the
corresponding value of the same strength aspect of the high thermal
conductivity material, and the high thermal conductivity material
in an unhardened condition and the high strength material in an
unhardened condition are precipitation hardenable together under
the same precipitation hardening conditions to achieve: an increase
in the value of at least one strength aspect of the high thermal
conductivity material relative to the unhardened condition, and an
increase in the value of at least one strength aspect of the high
strength material relative to the unhardened condition; and a
retainer that retains the nozzle tip against the nozzle housing
such that the bore communicates with the melt channel.
2. The nozzle assembly of claim 1, wherein the high thermal
conductivity material and the high strength material can be
precipitation hardened together at 450.degree. C. to achieve at
least a 96% increase in at least one strength aspect of the
high-strength material within three hours.
3. The nozzle assembly of claim 1, wherein the at least one
strength aspect of the high strength material and the at least one
strength aspect of the high thermal conductivity material each
comprise ultimate tensile strength.
4. The nozzle assembly of claim 1, wherein the at least one
strength aspect of the high strength material and the at least one
strength aspect of the high thermal conductivity material each
comprise yield strength.
5. The nozzle assembly of claim 1, wherein the at least one
strength aspect of the high strength material and the at least one
strength aspect of the high thermal conductivity material each
comprise endurance limit fatigue strength.
6. The nozzle assembly of claim 1, wherein the high thermal
conductivity material has a thermal conductivity of at least
approximately 80 W m.sup.-1 K.sup.-1.
7. The nozzle assembly of claim 1, wherein the high thermal
conductivity material has an ultimate tensile strength of at least
approximately 924 MPa.
8. The nozzle assembly of claim 1, wherein the high thermal
conductivity material is a copper alloy.
9. The nozzle assembly of claim 8, wherein the high thermal
conductivity material is a beryllium-copper alloy.
10. The nozzle assembly of claim 9, wherein the high thermal
conductivity material contains approximately 0.2-0.6% Be and
1.4-2.2% Ni, with balance Cu.
11. The nozzle assembly of claim 1, wherein the precipitation
hardened high strength material has an ultimate tensile strength of
at least approximately 2000 MPa, a yield strength of at least
approximately 1950 MPa, or an endurance limit fatigue strength of
at least approximately 850 MPa.
12. The nozzle assembly of claim 1, wherein the high strength
material has a thermal conductivity of at least approximately 15 W
m.sup.-1 K.sup.-1.
13. The nozzle assembly of claim 1, wherein the high strength
material is an iron alloy.
14. The nozzle assembly of claim 13, wherein the high strength
material is a maraging steel.
15. The nozzle assembly of claim 14, wherein the high strength
material contains approximately 18.5% Ni, 7.5-12.0% Co, and
3.25-4.8% Mo, with balance Fe.
16. The nozzle assembly of claim 1, wherein the high thermal
conductivity material and the high strength material can be
precipitation hardened together under the same precipitation
hardening conditions to achieve at least a 96% increase in at least
one strength aspect of the high strength material within six
hours.
17. The nozzle assembly of claim 1, wherein the high thermal
conductivity material and the high-strength material are integrally
joined together by welding.
18. The nozzle assembly of claim 17, wherein the high thermal
conductivity material and the high-strength material are integrally
joined together by electron beam welding.
19. The nozzle assembly of claim 1, wherein the body of the nozzle
tip further comprises a flange, and the retainer engages the flange
to retain the nozzle tip against the nozzle housing.
20. The nozzle assembly of claim 19, wherein the high thermal
conductivity material forms the entire bore and the high strength
material forms at least a portion of the flange.
21. The nozzle assembly of claim 1, wherein the precipitation
hardening conditions comprise an aging temperature in the range of
from 315.degree. C. to 540.degree. C.
22. The nozzle assembly of claim 21, wherein the aging temperature
is in the range of from 425.degree. C. to 510.degree. C.
23. The nozzle assembly of claim 22, wherein the aging temperature
is approximately 450.degree. C.
24. The nozzle assembly of claim 1, wherein the high thermal
conductivity material forms the entire bore.
25. The nozzle assembly of claim 1, wherein the at least one
strength aspect of the high strength material and the at least one
strength aspect of the high thermal conductivity material each
comprise at least one of ultimate tensile strength, yield strength,
and endurance limit fatigue strength.
26. The nozzle assembly of claim 1, wherein the at least one
strength aspect of the high strength material and the at least one
strength aspect of the high thermal conductivity material each
comprise ultimate tensile strength, yield strength, and endurance
limit fatigue strength.
Description
TECHNICAL FIELD
[0001] The invention relates, generally, to injection molding
systems, and more particularly, but not exclusively, to hot runner
components and injection molding systems comprising such
components, particularly nozzle assemblies and nozzle tips
therefor.
BACKGROUND OF THE INVENTION
[0002] The state of the art includes various nozzles and tips for
hot runner injection molding systems. Hot-runner nozzles are
typically either a valve-gate style or a hot-tip style. In the
valve-gate style, a separate stem moves inside the nozzle and tip
acting as a valve to selectively start and stop the flow of resin
through the nozzle. In the hot-tip style, a small gate area at the
end of the tip freezes off to thereby stop the flow of resin
through the nozzle.
[0003] An injection molding system using a hot-tip style nozzle
typically has a cooled mold with a small circular gate opening in
which the tip of the nozzle is inserted. The tip is typically
conical with a tapered point or other suitable configuration. In
operation, the tapered point is positioned in the circular gate to
thereby form an annular opening through which molten plastic or
other material is then transferred from the nozzle to the mold.
When the mold is full, flow stops. In an ideal plastic molding
cycle, the mold is typically cooled so that the plastic injected
into it soon solidifies. As the liquid plastic in the mold cools it
shrinks, which continues to allow plastic from the nozzle to move
into the mold. This step is referred to as "packing". The nozzle is
typically heated so that the molten plastic contained within it
remains liquid. The hot plastic moving through the gate area during
packing keeps the gate area from freezing until all the plastic in
the part has solidified. Eventually the gate freezes, the mold is
opened, and the part is ejected, thereby breaking the small amount
of frozen plastic at the gate area.
[0004] If the mold is opened before the gate has frozen, the
plastic will string from the nozzle to the mold. This is known as a
"gate stringing" and is unacceptable because the Waiting a long
time for the gate to freeze is also unacceptable because it adds
time to the molding cycle, which is desired to be as short as
possible to optimize system productivity.
[0005] Many prior art nozzle tips function in essentially the same
way, using the high thermal conductivity of the tip insert to
conduct heat from the heated nozzle body to the gate area. The heat
from the nozzle tip opens the gate at the beginning of the
injection cycle and keeps it open during the injection process, and
cooling from the mold cools and eventually freezes the gate after
packing is complete. If the tip is not hot enough, the gate may not
open and injection will not occur, or the gate will freeze too soon
causing poor-quality parts. If too much heat is transferred to the
tip, the gate will not freeze, resulting in stringing gates.
Therefore, for any particular nozzle tip and resin there is an
operating temperature window between the minimum temperature needed
to get the gate open and keep it open as desired through the
molding process, and the maximum temperature at which parts can be
made without stringing gates. If the operating window is narrow, it
may be difficult for molds with multiple cavities to consistently
make good parts in all cavities because of the many variables
associated with the injection molding process. One factor is
assembly tolerance stack up that varies tip heights in the gate.
For a conical tip, variations in tip height cause variations in the
size of the annulus between the tip and the gate through which
molten plastic flows. Another factor is variation in temperature of
the resin from the nozzle to nozzle due to heat loss at various
portions in the hot runner, or from flow imbalance in the hot
runner. Furthermore, resins have melt flow characteristics and an
optimum temperature range for processing that determines what
processing parameters are used in the injection molding process.
The flow characteristic for a resin inherently varies from batch to
batch. To keep resin costs down and to preclude sorting resin by
batch, molders often purchase resins in large quantities with a
specification allowing a large range for flow characteristic. One
batch of resin may run adequately for a given set of processing
parameters, but the next batch, having a different flow
characteristic, may not produce good parts using exactly the same
process settings.
[0006] If the nozzle does not provide enough heat at the tip to
keep the gate from freezing before the part is fully injected and
packed, the part may have voids or other quality problems making it
unacceptable. Heat is applied to the nozzle body by well-known
techniques and is conducted to the nozzle tip. Thus, in the prior
art, the tip material is generally made of high-conductivity
material that promotes the flow of heat to the nozzle tip, such as
a beryllium-copper alloy. It is important that the nozzle tip
provide the right amount of heat at the gate area to keep the
plastic in a liquid state as it flows through the gate, but also
that it allows the plastic to freeze in a reasonable time when flow
has stopped.
[0007] The tip must also resist corrosion, sustain compressive
loads from injection pressures that may reach, e.g., from 26 ksi
(179 MPa) to 40 ksi, (275 MPa) or higher at temperatures that may
reach, e.g., 350.degree. C., and resist wear when used with molding
material such as plastics containing fillers, e.g., glass or other
particulate materials. Since tips can wear out, it is desirable
that they be easily replaceable. Thus, the nozzle tip must provide
sufficient strength and resilience to sustain repeated uses under
high temperature and pressure without failure. However, at these
high pressures, existing nozzle tips exhibit an unacceptable
failure rate. For example, beryllium-copper alloys are
precipitation hardenable, and thus, can provide relatively high
strength and wear-resistance, but low fatigue resistance.
Accordingly, a great need exists for a nozzle tip that can
adequately conduct heat, while possessing sufficient wear
resistance and strength, particularly fatigue or endurance
strength, to increase both the lifetime of the part and the maximum
operating pressure. It is also desirable that tips be easily
changed to process different materials. Other components of an
injection molding assembly are subjected to similarly high stresses
and temperatures, and thus, would also benefit from a component
with high thermal conductivity and high strength.
[0008] U.S. Pat. No. 6,220,850 discloses a mold gate insert for a
valve-gate style injection molding machine that is formed of two
portions of differing materials. The material for the first portion
is selected for its hardness and wear resistance, and
non-precipitation hardening materials such as H13 tool steel, 420
ESR tool steel, and Vespel are disclosed as suitable materials. The
material for the second portion is selected for its thermal
conductivity, and beryllium copper alloy BeCu25 is disclosed as a
suitable material. The first portion and second portion are joined
together by physical means, such as press-fitting or swaging.
[0009] U.S. Patent Application Publication No. 2006/0196626
discloses the use of maraging steel alloys in injection molding
machinery for providing better wear resistance and fatigue
strength.
[0010] U.S. Pat. No. 4,451,974 discloses a nozzle for a valve-gate
style injection molding machine that is formed of an outer
conductive portion and a corrosion-resistant inner liner which are
threaded together. The outer conductive portion is formed of a
beryllium-copper alloy and the inner liner is formed of stainless
steel.
[0011] U.S. Patent Application Publication No. 2005/0045746
discloses various components of a hot runner injection molding
system, having a first portion and a second portion formed of
different materials and fused together. The disclosure describes
that the identities of the materials can be chosen for such
material properties as thermal conductivity, wear resistance,
strength, and resiliency.
[0012] U.S. Pat. No. 6,609,902 discloses a nozzle tip assembly that
includes a nozzle tip retainer having high thermal conductivity,
which holds a nozzle tip insert having lower thermal conductivity
and high wear resistance. Materials disclosed for the conductive
retainer include copper alloys and beryllium-copper alloys, and
materials disclosed for the less conductive tip insert include
stainless steel, tool steel, and carbide.
[0013] U.S. Pat. No. 6,164,954 discloses an injection nozzle that
includes an inner portion formed of a material having high wear
resistance and excellent thermal conductivity and an outer portion
formed of a material having high pressure resistance and good
thermal conductivity. The inner portion and the outer portion are
joined together with a press-fit or interference fit to form the
nozzle.
[0014] The present composite component and assembly are provided to
address the problems discussed above and other problems, and to
provide advantages and aspects not provided by prior nozzle
assemblies of this type. A full discussion of the features and
advantages of the present invention is provided in the following
summary and detailed description, which proceeds with reference to
the accompanying drawings.
SUMMARY OF THE INVENTION
[0015] The present disclosure provides a nozzle assembly having a
nozzle housing, a nozzle tip, and a retainer. The nozzle housing
has a melt channel extending therethrough. The nozzle tip includes
a body having a bore extending therethrough. The body is formed of
a precipitation hardened, high thermal conductivity material and a
precipitation hardened, high strength material, which are
integrally joined together to form the body. The thermal
conductivity of the high thermal conductivity material is greater
than the thermal conductivity of the high strength material, and at
least one strength aspect of the high strength material has a value
greater than the corresponding value of the same strength aspect of
the high thermal conductivity material. The high thermal
conductivity material and the high strength material can be
precipitation hardened together under the same precipitation
hardening conditions to achieve an increase in the value of at
least one strength aspect of the high thermal conductivity material
relative to the unhardened condition and an increase in the value
of at least one strength aspect of the high strength material
relative to the unhardened condition. The retainer retains the
nozzle tip against the nozzle housing such that the bore
communicates with the melt channel.
[0016] According to one aspect, the high thermal conductivity
material and the high strength material can be precipitation
hardened together at approximately 450.degree. C. to achieve at
least a 96% strength increase of the high-strength material within
three hours.
[0017] According to another aspect, the high thermal conductivity
material has a thermal conductivity of at least approximately 80 W
m.sup.-1 K.sup.-1, and the precipitation hardened, high strength
material has an ultimate tensile strength of at least approximately
2000 MPa, a yield strength of at least approximately 1950 MPa, or
an endurance limit fatigue strength of at least approximately 850
MPa.
[0018] According to another aspect, the high thermal conductivity
material is a beryllium-copper alloy and the high strength material
is a maraging steel. In one example, the high thermal conductivity
material contains approximately 0.2-0.6% Be and 1.4-2.2% Ni, with
balance Cu, and the high strength material contains approximately
18.5% Ni, 7.5-12.0% Co, and 3.25-4.8% Mo, with balance Fe.
[0019] According to another aspect, the body further includes a
flange, and the retainer engages the flange to retain the nozzle
tip against the nozzle housing. The high thermal conductivity
material forms the entire bore, and the high strength material
forms at least a portion of the flange.
[0020] According to another aspect, the high thermal conductivity
material and the high-strength material are integrally joined
together by welding, such as by electron beam welding.
[0021] According to another aspect, the at least one increased
strength aspect of the high strength material and the at least one
increased strength aspect of the high thermal conductivity material
each includes at least one of ultimate tensile strength, yield
strength, and endurance limit fatigue strength.
[0022] Other features and advantages of the invention will be
apparent from the following specification taken in conjunction with
the following drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Certain exemplary embodiments of the present invention are
described below with reference to the accompanying drawings in
which:
[0024] FIG. 1 is a cross-sectional view of a portion of one
embodiment of an injection molding assembly, including a hot runner
assembly;
[0025] FIG. 2 is a cross-sectional view of one embodiment of a
nozzle assembly for an injection molding assembly;
[0026] FIG. 2A is a focused view of a portion of the nozzle
assembly of FIG. 2;
[0027] FIG. 3 is a cross-sectional view of another embodiment of a
nozzle assembly for an injection molding assembly;
[0028] FIG. 4 is a cross-sectional view of a further embodiment of
a nozzle assembly for an injection molding assembly;
[0029] FIG. 5 is a cross-sectional view of one embodiment of a
composite nozzle tip;
[0030] FIG. 6 is a cross-sectional view of a prior art nozzle
tip;
[0031] FIG. 7 is a cross-sectional view of one embodiment of a
composite retainer;
[0032] FIG. 8 is a cross-sectional view of one embodiment of a
composite retainer plate;
[0033] FIG. 9 is a cross-sectional view of a multi-probe nozzle
assembly incorporating the retainer plate of FIG. 8;
[0034] FIG. 10 is a perspective view of another embodiment of a
composite nozzle tip;
[0035] FIG. 11 is a cross-sectional view of the composite nozzle
tip of FIG. 10;
[0036] FIG. 12 is a cross-sectional view of a further embodiment of
a composite nozzle tip;
[0037] FIG. 13 is a cross-sectional view of one embodiment of a
portion of an injection molding assembly, including a hot runner
assembly;
[0038] FIG. 14 is a cross-sectional view of a sprue bushing of the
hot runner assembly of FIG. 13;
[0039] FIG. 15 is a cross-sectional view of a manifold bushing of
the hot runner assembly of FIG. 13;
[0040] FIG. 16 is a cross-sectional view of a nozzle assembly and a
gate insert of the hot runner assembly of FIG. 13;
[0041] FIG. 17 is a cross-sectional view of a mold cavity of the
hot runner assembly of FIG. 13, defined by a mold cavity insert and
a core insert;
[0042] FIG. 18 is a cross-sectional view of another embodiment of a
composite nozzle tip;
[0043] FIG. 19 is a cross-sectional view of a blank from which the
composite nozzle tip of FIG. 18 is manufactured;
[0044] FIG. 20 is a cross-sectional view of another embodiment of a
composite nozzle tip;
[0045] FIG. 21 is a cross-sectional view of a blank from which the
composite nozzle tip of FIG. 20 is manufactured;
[0046] FIG. 22 is a cross-sectional view of another embodiment of a
composite nozzle tip;
[0047] FIG. 23 is a cross-sectional view of a blank from which the
composite nozzle tip of FIG. 22 is manufactured;
[0048] FIG. 24 is a cross-sectional view of another embodiment of a
composite nozzle tip;
[0049] FIG. 25 is a cross-sectional view of a portion of a blank
from which the composite nozzle tip of FIG. 24 is manufactured;
[0050] FIG. 26 is a cross-sectional view of another embodiment of a
composite nozzle tip; and
[0051] FIG. 27 is a cross-sectional view of a portion of a blank
from which the composite nozzle tip of FIG. 26 is manufactured.
[0052] The same reference number may be used in the various
drawings to label the same, similar or generally corresponding
components, features, etc.
DETAILED DESCRIPTION
[0053] While this invention is susceptible of embodiments in many
different forms, there are shown in the drawings and will herein be
described in detail certain exemplary embodiments of the invention
with the understanding that the present disclosure is to be
considered as an exemplification of the principles of the invention
and is not intended to limit the broad aspect of the invention to
the embodiments illustrated.
[0054] Generally, a composite material component for an injection
molding assembly 10 is provided herein. The component includes a
first portion formed of a precipitation hardened, high thermal
conductivity material and a second portion formed of a
precipitation hardened, high strength material, and the high
thermal conductivity material and the high strength material are
unitized or integrally joined together, e.g., by welding or other
methods further described below. The thermal conductivity of the
high thermal conductivity material is greater than the thermal
conductivity of the high strength material. The strength of the
high-strength material is greater than the strength of the high
thermal conductivity material. The high thermal conductivity
material and the high strength material can be precipitation
hardened together under the same precipitation hardening conditions
after being joined together to form part of or the entire composite
component. Advantageously, through this precipitation hardening,
both materials can achieve greater strength as compared to
otherwise identical materials which have been annealed, but have
not been precipitation hardened. As described in more detail below,
many different composite components of the injection molding
assembly 10 may be produced through the principles disclosed
herein. In one embodiment, the component is a composite nozzle tip,
generally referred to using reference numeral 16, for use with the
injection molding assembly 10, as described further below.
[0055] Referring to FIG. 1, one embodiment of a hot runner system
11, which is a well-known component of an injection molding
assembly 10 of the hot-tip style, is shown. The hot runner system
11 has a melt channel 14 extending therethrough, in fluid
communication with an injection unit 13 adapted to contain a
pressurized, flowable material, in a well known manner. A plurality
of fasteners 55 rigidly affix a manifold plate 32 to a backing
plate 30. A sub-manifold 44 is located in a cavity 57 formed in
manifold plate 32. A spacer 56 is located between sub-manifold 44
and backing plate 30 to reduce thermal communication therebetween.
In the embodiment shown, the spacer 56 is rigidly affixed to the
sub-manifold 44 and is allowed to slide along a surface of the
backing plate 30 thereby allowing thermal expansion. However, the
spacer 56 could also be rigidly affixed to the backing plate 30 and
allowed to slide along a surface of the sub-manifold 44. An
insulator 42 is located between manifold plate 32 and sub-manifold
44 to maintain a space therebetween and reduce thermal
communication. In the embodiment shown, the insulator 42 is
inserted into a first hole located in sub-manifold 44 and extends
into a second hole located in manifold plate 32 such that it
inhibits relative motion between the sub-manifold 44 and the
manifold plate 32 in the area of a sealing member 45. A bridge
manifold 50 is located in a manifold cavity 53 formed in the
backing plate 30. A plunger 51, preferably comprised of a plunger
bushing 52 and a spring means 54, maintains a gap between bridge
manifold 50 and backing plate 30 to reduce thermal communication
therebetween. Heaters 43 supply heat to the components of the hot
runner assembly 11.
[0056] A first melt channel segment 48 and a second melt channel
segment 46 form portions of the melt channel 14 extending through
the hot runner assembly 11. The first and second melt channel
segments 48, 46 are located in a bridge manifold 50 and the
sub-manifold 44 respectively, and are in fluid communication with
each other. A sealing member 45 is inserted in a recess of the
sub-manifold 44 and is aligned with the first melt channel segment
48 and the second melt channel segment 46. In one embodiment, the
spring means 54 is comprised of a series of stacked Belleville
springs to create a resilient spacer to adjust to thermal expansion
of the various components. The spring means 54 can also be selected
from the group consisting of a compression spring and a resilient
material.
[0057] Nozzle assembly 40 has a nozzle melt channel segment 21
extending therethrough and forming a part of the melt channel 14.
The nozzle melt channel segment 21 is in fluid communication with
the second melt channel segment 46 for the communication of fluid
to a mold cavity 38. In the embodiment shown, the nozzle assembly
40 has a heater 41, as is well known in the art to maintain
material in the nozzle melt channel segment 21 in a flowable state.
The heater 41 may be selected from the group consisting of a
resistance heater, induction heater, heat pipe, thick film heater
and a thin film heater. In the embodiment shown, the nozzle
assembly 40 is located in the manifold plate 32 and extends through
a cavity plate 34 to a gate or the cavity 38. The cavity plate 34
is aligned with the manifold plate 32 by at least one alignment pin
58, as is well known in the art. A core plate 36 is located in
alignment with cavity plate 34 to form cavity 38 which defines the
shape of the molded article to be produced.
[0058] One embodiment of the nozzle assembly 40, which utilizes a
composite nozzle tip 16A in accordance with this disclosure and is
suitable for use in the assembly of FIG. 1, is illustrated in
greater detail in FIGS. 2 and 2A. As shown, the nozzle assembly 40
comprises an elongated nozzle housing 12 having the nozzle melt
channel segment 21 extending therethrough, forming part of the melt
channel 14. The composite nozzle tip 16A is installed at the
proximal end 18 of the nozzle housing 12 so that a tip channel
segment 22 formed in nozzle tip 16A is in fluid communication with
the melt channel 14 and has at least one outlet aperture 74 in
fluid communication with the tip channel 22. In certain exemplary
embodiments, nozzle tip 16A is retained at the proximal end 18 of
nozzle housing 12 by a tip retainer 24 having distal surface 28
(See FIG. 3) and shoulder 23, one or both of which bear against an
adjacent surface of the nozzle tip. Retainer 24 is removably
affixed to a proximal end 18 of the nozzle housing by threads 26 or
another connecting structure or feature. The tip retainer 24 is
preferably configured to receive and retain the nozzle tip 16A when
the tip retainer 24 is connected to the proximal end 18 of the
nozzle housing 12. In the embodiment shown, the nozzle housing 12
and tip retainer 24 are constructed, arranged, and threaded such
that the tip retainer 24 installs on external threads on the nozzle
housing 12. In this embodiment, the nozzle housing 12 and tip
retainer 24 are substantially cylindrical in cross section with
substantially equal outside diameters, so that a substantially
cylindrical external heater 41 can be installed over nozzle housing
12 and tip retainer 24. Heater 41 supplies heat to nozzle housing
12 and tip retainer 24 to keep the material in melt channel 14 and
tip channel 22 molten.
[0059] In another embodiment, shown in FIG. 3, the tip retainer 24
threads into internal threads in the nozzle housing. In this
embodiment, the nozzle housing 12 and tip retainer 24 are
configured with internal threads 26 in the nozzle housing 12 and
mating external threads on the tip retainer 24. The tip retainer 24
installs in the internal threads 26 to retain the nozzle tip 16B.
The tip retainer 24 has both a shoulder 23 and a distal surface 28
which engage and retain the nozzle tip 16B.
[0060] In a further embodiment, shown in FIG. 4, the nozzle
assembly 40 can be configured without a removable tip retainer 24.
In this embodiment, the tip retainer 24 is integrally joined with
the nozzle housing 12, such as by forming them of a single piece,
or by welding, brazing, soldering, and similar methods. When made
of a different material then that of the nozzle housing 12, the
retainer portion 24 may be welded or brazed with high temperature
brazing material to the nozzle housing 12. The nozzle tip 16E can
be attached to the tip retainer 24 by brazing with a relatively
low-temperature brazing material which would still allow nozzle tip
16E to be removed from tip retainer 24 by reheating the assembly to
a temperature high enough to melt the low-temperature brazing
material, but not so high as to melt the high temperature brazing
material. Alternatively, the nozzle housing 12 and tip retainer 24
could be one integral piece made of the same material. In another
example, the tip retainer 24 could have the tip 16E brazed or
welded to it, and have tip retainer 24 threadably engage the nozzle
housing 12. In still another example, the tip retainer 24 may be
removably affixed to the nozzle housing 12 by a low-temperature
brazed interface, and the tip retainer 24 may be configured to
mechanically retain the nozzle tip 16E in similar fashion to that
of the embodiment of FIG. 2. It must be recognized that, for the
embodiments requiring brazing, temperatures high enough to melt
even the low-temperature brazing material may be high enough to
undesirably degrade the material properties of the tip retainer
24.
[0061] In all the embodiments above, an optional nozzle seal 25 is
affixed to the proximal end of tip retainer 24, and has a flange 29
which contacts and seals against the mold (not shown). It should be
noted, that one of ordinary skill in the art is familiar with a
myriad of configurations for nozzle seals and the like that may
include a bubble area 27 (FIG. 2A) formed between flange 29 and
nozzle tip 16 where molten material is allowed to collect to
enhance thermal insulation of the injection nozzle 10 from the
mold. In certain exemplary embodiments, nozzle seal 25 is made of a
lower thermal conductivity material than tip retainer 24 to
minimize heat transfer between the retainer 24 and the mold (not
shown). Nozzle seal 25 in certain exemplary embodiments is
annularly spaced from the nozzle tip 16 to minimize the heat
transfer between nozzle seal 25 and nozzle tip 16. One suitable
material for nozzle seal 25 is a tool steel, which has a thermal
conductivity of around 14 W m.sup.-1 K.sup.-1. Nozzle seal 25 in
certain exemplary embodiments is fused to tip retainer 24 at
interface 23 by electron-beam welding, brazing, or other such
process. Alternatively, nozzle seal 25 may be made with a press fit
at interface 23, or nozzle seal 25 may threadably engage tip
retainer 24.
[0062] It is contemplated that all known configurations for nozzle
assemblies may be used in accordance with the disclosed component
and method. For example, although a nozzle tip 16 is disclosed with
reference to a hot-tip style injection molding assembly, the
principles disclosed herein can be used to provide a superior
nozzle tip for a valve-gate style injection molding assembly.
[0063] A composite nozzle tip 16 in accordance with certain
exemplary embodiments is illustrated in more detail in FIG. 5,
which is suitable for use as the nozzle tips 16A-16E shown in FIGS.
2-4. As shown in FIG. 5, nozzle tip 16 has a body 60 having a
connection member 62 adapted for connection to the injection
molding assembly 10 and a bore 64 extending through the body 60.
The body 60 is formed of materials including a precipitation
hardened, high thermal conductivity material 66 and a precipitation
hardened, high strength material 68, where the high thermal
conductivity material 66 and the high strength material 68 are
integrally joined together to form the body 60. In other words, the
body 60 includes a first portion 66 and a second portion 68
integrally joined together to form the body 60, where the first
portion 66 is formed of a precipitation hardened, high thermal
conductivity material and the second portion is 68 formed of a
precipitation hardened, high strength material. In general, the
thermal conductivity of the high thermal conductivity material 66
is greater than the thermal conductivity of the high strength
material 68, and the strength of the high strength material 68 is
greater than the strength of the high thermal conductivity material
66. In contrast, a prior art nozzle tip 19 is illustrated in FIG.
6, constructed of a single material.
[0064] As stated above, the first portion 66 and the second portion
68 are integrally joined to form the body 60 of the nozzle tip 16.
As used herein, integral joining is defined as including permanent
or semi-permanent technique of joining two or more materials
together, e.g., by integral structure, surface-to-surface joinder
or other interface between them to create a single or unitized
piece, as contrasted with mechanical joining techniques such as
using only threads, fasteners or friction/press fit connections.
Integral joining is found to provide advantageous performance the
disclosed injection molding components for withstanding the high
thermal and physical stresses and thermal and physical cycling
experienced by such components. Such mechanical joining techniques
can be used, however, in at least certain exemplary embodiments of
the composite nozzle tips or other composite components disclosed
here, in conjunction with (including as a part of) the aforesaid
permanent or semi-permanent joinder. A non-exhaustive list of
integral joining techniques includes: any of a large variety of
welding techniques, brazing, soldering, and forming of a single
piece, such as by molding or powder metallurgy. The variety of
welding techniques referred to includes, without limitation, gas
flame welding techniques; electric arc welding techniques; energy
beam welding techniques, such as laser welding, electron beam (EB)
welding, and laser-hybrid welding; resistance welding techniques,
such as spot welding, shot welding, seam welding, flash welding,
projection welding, and upset welding; and solid-state welding
techniques, such as forge welding, friction/mechanical welding,
ultrasound welding, explosion welding, co-extrusion welding, cold
welding, diffusion welding, diffusion bonding, high frequency
welding, hot pressure welding, induction welding, and roll welding.
In the embodiment shown in FIG. 5, the first and second portions
66,68 are joined using EB welding, creating a weld zone 67 between
the portions 66,68.
[0065] As shown in FIG. 5, the nozzle tip 16 is formed of two
pieces 69. The tip 16 shown includes a connection member 62 adapted
for connection to the injection molding assembly 10 and a bore 64
extending through the body 60. In the embodiment shown, the
connection member 62 is a flange 62 extending around the periphery
of the body 60. As shown in FIGS. 2-3, the tip 16 can be attached
to the nozzle assembly 40 by the retainer 24, which grips and
engages the flange 62. In other embodiments, the tip 16 may connect
to the nozzle assembly 40 in a different manner, such as in the
manner of the embodiment shown in FIG. 4 and described above. The
bore 64 is generally a cylindrical passage through the center of
the body 60 to form a tip channel segment 22, which is a portion of
the melt channel 14. The bore 64 is in communication with the
nozzle melt channel segment 21 through an inlet opening 70 at an
inlet end 72, and is also in communication with at least one outlet
aperture 74 at an outlet end 76. Accordingly, the flowable material
flows into the bore 64 through the inlet opening 70, through the
bore 64, and out of the bore 64 into the mold cavity 38 through the
outlet aperture 74. Thus, the flowable material can flow from the
injection unit 13 to the mold cavity 38.
[0066] In the embodiment illustrated in FIG. 5, the first portion
66, or high thermal conductivity material 66, forms the entire bore
64, as well as the outlet end 76 of the nozzle tip 16. It is
contemplated that the high strength material 68 can advantageously
be placed in positions where the most stress or force, e.g.,
tip-retaining force, is exerted on the nozzle tip 16 to absorb this
stress. Frequently, high stresses are concentrated at or around the
connection member 62, due to the forces necessary to seal the
nozzle tip 16 to the nozzle assembly 40. Thus, in the embodiment of
FIG. 5, the second portion 68, or high strength material 68, forms
the entire flange 62 to absorb this stress and also forms a shell
over the high thermal conductivity bore 64,66 for at least a
portion of the length of the bore 64 proximate the flange 62. In
other embodiments, the high strength material 68 may be positioned
around the bore 64 of the nozzle tip 16 and the high thermal
conductivity material 66 may be positioned around the outside of
the nozzle tip 16. In further embodiments, the inner and outer
peripheries of the nozzle tip 16 may be formed from the high
thermal conductivity material 66, and the high strength material 68
may form an inner "band" sandwiched between the two pieces of high
thermal conductivity material 66. Other embodiments are
contemplated where the high strength material 68 is positioned to
absorb stresses on the nozzle tip 16 and the high thermal
conductivity material 66 is positioned to conduct heat through the
nozzle tip 16. Thus, in other embodiments, the configuration,
placement, and proportions of the high thermal conductivity
material 66 and the high strength material 68 can vary. Further, it
is understood that the term "portion" is not necessarily considered
to be synonymous with "piece," and does not imply that the entire
portion 66,68 is continuous throughout the nozzle tip 16. The
pieces 69 referred to above are unitary pieces 69 which are used in
the construction of the nozzle tip 16. One or both of the first and
second portions 66,68 may be formed from multiple pieces, and the
composite nozzle tip 16 may contain two non-continuous areas of
high thermal conductivity material 66 and/or high strength material
68. For example, the flange 62 and the outlet end 76 may be formed
of high strength material 68, completely separated by a bridging
piece of high thermal conductivity material 66. In such an
embodiment, the nozzle tip 16 would be formed from three pieces,
and the second portion 68 would comprise two pieces.
[0067] The high thermal conductivity material of the composite
nozzle tips and other composite components disclosed here, e.g.,
for portions 66 in the illustrated nozzle tip embodiments, has a
higher thermal conductivity than the high strength material.
Thermal conductivity can be measured using standard ASTM E1530.
Additionally, the high thermal conductivity material is hardenable
by precipitation hardening, also known as aging or age hardening.
Certain copper alloys, for example, provide high thermal
conductivity and are precipitation hardenable to increase their
strength. In certain exemplary embodiments, the high thermal
conductivity material is a beryllium-copper alloy, such as an alloy
made per any of the ASTM C17000 series specifications. BeCu3 (ASTM
C17510), which contains approximately 0.2-0.6% Be and 1.4-2.2% Ni,
with balance Cu (approximately 98%) is one such beryllium-copper
alloy suitable for at least certain exemplary embodiments. BeCu25
(ASTM C17200), which contains approximately 1.8-2.0% Be, 0.2% min.
Co+Ni, 0.6% max. Co+Ni+Fe, and 0.1% max. Pb, with balance Cu
(approximately 97%), is another suitable beryllium-copper alloy.
BeCu3 and BeCu25 are precipitation hardenable, for example, by
aging as specified in ASTM Temper Code TF00. When used in at least
certain exemplary embodiments of the nozzle tips disclosed herein,
beryllium-copper alloys can provide the additional advantage of
having a high thermal expansion coefficient, which creates better
sealing of the nozzle tip 16. In certain embodiments another copper
alloy or other high thermal conductivity, precipitation hardenable
material may be used as the high conductivity material. It is
contemplated that the composite component may include more than one
high conductivity material. In certain exemplary embodiments, where
the high conductivity material is BeCu3, the high thermal
conductivity material has a thermal conductivity in the range of
from 80-260 W m.sup.-1 K.sup.-1. In certain embodiments, the high
thermal conductivity material has a thermal conductivity in the
range of from 100-240 W m.sup.-1 K.sup.-1. By comparison, in at
least certain such exemplary embodiments the high strength material
has a thermal conductivity in the range of from 15-60 W m.sup.-1
K.sup.-1.
[0068] The high strength material used in a composite nozzle tip or
other composite component in accordance with this disclosure, e.g.,
the material of portion 68 in the illustrated nozzle tip
embodiments, has a higher strength than the high conductivity
material of the component. Additionally, the high strength material
is hardenable by precipitation hardening. High strength materials
suitable for at least certain exemplary embodiments of the
composite nozzle tips and other composite components disclosed here
include, e.g., maraging steel alloys, which typically contain a
substantial amount of iron and nickel, along with cobalt and/or
titanium, provide high strength and are precipitation hardenable to
further increase their strength. In certain exemplary embodiments,
the high strength material is a maraging steel, such as an alloy
made per the ASTM A538 specifications, for example, VascoMax.RTM.
C300, which contains approximately 18.5% Ni, 9.0% Co, 4.8% Mo, 0.6%
Ti, 0.1% Al, 0.1% max. Si, 0.1% max. Mn, 0.03% max. C, 0.01% max.
S, 0.01% max. P, 0.01% Zr, and 0.003% B, with balance Fe
(approximately 67%). VascoMax.RTM. C300 is precipitation hardenable
by aging as described herein below. In other embodiments, another
maraging steel or other high strength, precipitation hardenable
material may be used as the high strength material, including
another of the VascoMax.RTM. series of maraging steel alloys from
Allegheny Technologies. Among the other available VascoMax.RTM.
alloys that can be used in at least certain exemplary embodiments
of the nozzle tips and other composite components disclosed here,
are VascoMax.RTM. C200, C250, and C350, which generally contain
approximately 18.5% Ni, 7.5-12.0% Co, and 3.25-4.8% Mo, with
balance Fe and various trace elements, and cobalt-free titanium
strengthened VascoMax.RTM. T200, T250, and T300, which generally
contain approximately 18.5% Ni, 0.7-1.85% Ti, and 3.0-4.0% Mo, with
balance Fe and various trace elements. It is contemplated that at
least certain exemplary embodiments of the composite nozzle tips
and other composite components disclosed here may include more than
one high strength material.
[0069] As defined herein, strength is measured in any one of
several ways. That is, the high strength material is stronger than
the high thermal conductivity material of the same component in at
least one strength aspect, and in certain exemplary embodiments is
stronger in more than one strength aspect. For example, strength
can be measured as ultimate tensile strength, which can be measured
using standards ASTM E8 and ASTM E21. In certain exemplary
embodiments, e.g., where the high strength material is one of the
VascoMax.RTM. series of alloys, the ultimate tensile strength of
the hardened high strength material at room temperature is at least
1400 MPa and up to at least 1500 MPa for VascoMax.RTM. C200, at
least 1800 MPa and up to at least 1950 MPa for VascoMax.RTM. C250,
at least 2000 MPa and up to at least 2200 MPa for VascoMax.RTM.
C300, at least 2350 MPa and up to at least 2450 MPa for
VascoMax.RTM. C350, at least 950 MPa and up to at least 1450 MPa
for VascoMax.RTM. T200, at least 1200 MPa and up to at least 1800
MPa for VascoMax.RTM. T250, and at least 1150 MPa and up to at
least 2050 MPa for VascoMax.RTM. T300. In certain other exemplary
embodiments, strength is measured as 0.2% offset yield strength
(referred to herein as simply "yield strength") using standards
ASTM E8 and ASTM E21. In certain exemplary embodiments, e.g., where
the high strength material is one of the VascoMax.RTM. series of
alloys, the yield strength of the hardened high strength material
at room temperature is at least 1350 MPa and up to at least 1450
MPa for VascoMax.RTM. C200, at least 1750 MPa and up to at least
1900 MPa for VascoMax.RTM. C250, at least 1950 MPa and up to at
least 2150 MPa for VascoMax.RTM. C300, at least 2300 MPa and up to
at least 2350 MPa for VascoMax.RTM. C350, at least 900 MPa and up
to at least 1400 MPa for VascoMax.RTM. T200, at least 1100 MPa and
up to at least 1750 MPa for VascoMax.RTM. T250, and at least 1050
MPa and up to at least 2000 MPa for VascoMax.RTM. T300. In certain
exemplary embodiments strength is measured as endurance limit
fatigue strength, which can be measured using standards ASTM E606
and ASTM E466. In certain exemplary embodiments, e.g., where the
high strength material is one of the VascoMax.RTM. series of
alloys, the endurance limit fatigue strength of the hardened high
strength material at room temperature is at least 750 MPa for
VascoMax.RTM. C200, C250, and C350, at least 850 MPa for
VascoMax.RTM. C300, at least 750 MPa for VascoMax.RTM. T200 and
T250, and at least 800 MPa for VascoMax.RTM. T300. By comparison,
in the annealed condition, VascoMax.RTM. C200 has an ultimate
tensile strength of 965 MPa and a yield strength of 689 MPa,
VascoMax.RTM. C250 has an ultimate tensile strength of 965 MPa and
a yield strength of 655 MPa, VascoMax.RTM. C300 has an ultimate
tensile strength of 1034 MPa and a yield strength of 758 MPa,
VascoMax.RTM. C350 has an ultimate tensile strength of 1138 MPa and
a yield strength of 827 MPa, VascoMax.RTM. T200 has an ultimate
tensile strength of 965 MPa and a yield strength of 689 MPa,
VascoMax.RTM. T250 has an ultimate tensile strength of 965 MPa and
a yield strength of 655 MPa, and VascoMax.RTM. T300 has an ultimate
tensile strength of 1034 MPa and a yield strength of 758 MPa.
[0070] As stated above, both the high conductivity material and the
high strength material of the composite nozzle tips and other
composite components disclosed here are precipitation hardenable to
increase their respective strengths. In certain exemplary
embodiments the high thermal conductivity material and the high
strength material are selected such that they can be precipitation
hardened under the same precipitation hardening conditions.
Precipitation hardening (also known as precipitation strengthening
or age hardening/strengthening) is a well-known technique in the
art of metallurgy for increasing the strength of a material.
However, only a select number of materials can be precipitation
hardened, including, for example, certain iron and copper alloys,
as well as many aluminum and titanium alloys. Precipitation
hardening is presently understood to rely on changes in solid
solubility with temperature to produce particles of second phase
within the metal matrix. These particles impede the movement of
dislocations (defects) in a crystal's lattice. Movement of
dislocations can allow the material to deform, so impeding the
movement of these dislocations hardens and strengthens the
material. The size and dispersion of these particles affects the
amount of strengthening achieved through precipitation hardening,
and the precipitation hardening conditions affect the size and
dispersion of the particles. Materials precipitation harden only
under certain conditions, including a certain temperature range.
The material to be hardened typically is brought to a specific
temperature, which is normally much greater than ambient
temperature and is known as the aging temperature. The material is
then held at the temperature for a predetermined time, known as the
aging time, which allows the precipitate particles to form.
Different materials having different compositions typically
precipitation harden at different temperatures and rates. Thus,
different materials often do not precipitation harden adequately
under the same conditions. For example, when two incompatible
materials are hardened together, one of the materials may overage,
while the other is not aged enough, resulting in one or both of the
materials obtaining less than desirable properties. Accordingly,
materials for various embodiments of the composite nozzle tips or
other composite components disclosed here should be selected in
accordance with the forgoing principles.
[0071] Precipitation hardening generally increases the value of at
least one strength aspect of the precipitation hardenable material
relative to the same material in an unhardened condition, as
described below, and can often increase the values of several
strength aspects. Those skilled in the art would understand that
the term "unhardened condition" refers to a material that has not
been significantly strengthened through growth and/or dispersion of
precipitates through an aging process, such as when the material is
annealed and cooled in such a manner that precipitates do not form
in significant concentration and size to significantly strengthen
the material. It is also understood that, in the unhardened
condition, the material may contain some precipitates and may
experience minor strengthening as a result.
[0072] As described herein, during processing, the pieces or
portions of the composite nozzle tips or other composite components
disclosed here, e.g., pieces 69 used to construct the component of
the illustrated nozzle tip embodiments, can be machined to the
correct shape and then welded together to create the finished
component or an intermediate product for the finished component.
Both machining and welding are more easily and effectively done
when the high strength material has been annealed prior to
processing. Annealing softens the material, making it more
machinable, and also relieves internal stresses in the materials,
making cracking incident to welding less likely. Selecting the high
thermal conductivity material and the high strength material such
that they can be machined, joined and then together precipitation
hardened under the same precipitation hardening conditions, is
advantageous because it allows the component to be hardened in the
assembled configuration. Thus, the pieces used to form the
component can be machined and welded (or otherwise joined, as
discussed above) while the high strength material is in the
annealed condition, and then the entire component can be
precipitation hardened after such assembly and joining. The high
thermal conductivity material can also be annealed prior to
machining, which is advantageous for certain materials. BeCu3 is
easier to machine in a pre-hardened condition, because the softness
of annealed BeCu3 can cause difficulties with machining.
Additionally, BeCu3 can be precipitation hardened in the
pre-hardened state without averaging, and thus, in some exemplary
embodiments, a BeCu3 high thermal conductivity material is
machined, assembled, and precipitation hardened starting from a
pre-hardened condition. However, BeCu3 can also be machined,
assembled, and hardened in the annealed condition. Other materials
experience greater advantages by annealing prior to processing. For
example, BeCu25 can overage if precipitation hardened in a
pre-hardened condition, and thus, annealing prior to processing is
advantageous for BeCu25.
[0073] When the materials are precipitation hardened together at
the same conditions, both materials can achieve greater strength as
compared to otherwise identical materials which have been annealed,
but have not been precipitation hardened. In certain exemplary
embodiments, both materials can exhibit at least 25% greater
strength after precipitation hardening, as compared to otherwise
identical materials which have been annealed, but have not been
precipitation hardened. In certain other exemplary embodiments,
both materials can exhibit at least 50% greater strength after
precipitation hardening, as compared to otherwise identical
materials which have been annealed, but have not been precipitation
hardened. In certain other exemplary embodiments embodiment, both
materials can exhibit at least 75% greater strength after
precipitation hardening, as compared to otherwise identical
materials which have been annealed, but have not been precipitation
hardened. In certain other exemplary embodiments, both materials
can exhibit at least 100% greater strength after precipitation
hardening, as compared to otherwise identical materials which have
been annealed, but have not been precipitation hardened. In further
exemplary embodiments, one of the materials may exhibit a higher
degree of strength increase than the other. For example, one
material may achieve a strength increase of 75% while the other
achieves a strength increase of 50%. As described above, the
increase in strength can be an increase in at least one of yield
strength, ultimate tensile strength, and endurance limit fatigue
strength.
[0074] As noted above, in certain exemplary embodiments, the high
conductivity material is a beryllium-copper alloy, such as BeCu3 or
BeCu25, and the high strength material is a maraging steel, such as
an alloy in the VascoMax.RTM. series. The optimum aging temperature
for the alloys in the VascoMax.RTM. series is approximately
450.degree. C. to 510.degree. C., and VascoMax.RTM. T-Series alloys
can be aged at approximately 315.degree. C. to 540.degree. C. By
comparison, the optimum aging temperature for BeCu3 is
approximately 480.degree. C., and the optimum aging temperature for
BeCu25 is approximately 260.degree. C. to 425.degree. C., and these
materials can be adequately precipitation hardened at temperatures
slightly outside the respective ranges. In one example, where the
high thermal conductivity material is BeCu3 or BeCu25 and the high
strength material is VascoMax.RTM. C300, both materials can be
precipitation hardened, e.g., by heating for three hours to a
temperature in the range of from approximately 315-540.degree. C.,
preferably in the range of from approximately 425-510.degree. C.,
and most preferably approximately 450.degree. C. It is understood
that the time and temperature for this aging may be adjusted as
desired.
[0075] The degree of precipitation hardening is described below by
way of an example. VascoMax.RTM. C300, which is a suitable high
strength material for at least certain exemplary embodiments, has a
yield strength of approximately 758 MPa and an ultimate tensile
strength of approximately 1034 MPa in the annealed condition. In
certain exemplary embodiments, the component, e.g., a nozzle tip
16, is formed from VascoMax.RTM. C300 and BeCu3, and the materials
then are aged at 450.degree. C. for three hours, resulting in the
VascoMax.RTM. C300 achieving a yield strength of 1999 MPa (an
increase of approximately 163%) and an ultimate tensile strength of
2027 MPa (an increase of approximately 96%), as well as an
endurance limit fatigue strength of 862 MPa. In comparison, BeCu3
has an ultimate tensile strength of around 320 MPa and a yield
strength of around 160 MPa in the annealed condition. When aged at
450.degree. C. for three hours, BeCu3 can obtain an ultimate
tensile strength of around 924 MPa (an increase of approximately
189%) and a yield strength of around 807 MPa (an increase of
approximately 404%), as well as an endurance limit fatigue strength
of around 340 MPa. When annealed at these same conditions, BeCu25
can obtain an ultimate tensile strength of around 1517 MPa, a yield
strength of around 1344 MPa, and no endurance limit for infinite
cycles. When precipitation hardened in the optimum range
(450-510.degree. C.), Vascomax.RTM. C300 can achieve a yield
strength of up to at least 2166 MPa (an increase of approximately
186%) and an ultimate tensile strength of up to at least 2215 MPa
(an increase of approximately 114%), with concurrent hardening also
of the beryllium-copper alloy high thermal conductivity
material.
[0076] In certain exemplary embodiments the high thermal
conductivity material and the high strength material are
precipitation hardened together at an aging temperature in the
range of from 450.degree. C. to 510.degree. C., for up to 6 hours,
to achieve at least a 96% yield strength increase, and up to a 195%
yield strength increase, of the high strength material. In certain
exemplary embodiments the high thermal conductivity material and
the high strength material are precipitation hardened together at
an aging temperature in the range of from 480.degree. C. to
510.degree. C., for up to 6 hours, to achieve at least a 104% yield
strength increase, and up to a 195% yield strength increase, of the
high strength material. In certain exemplary embodiments the high
thermal conductivity material and the high strength material are
precipitation hardened together at an aging temperature in the
range of from 315.degree. C. to 540.degree. C., for up to 6 hours,
to achieve at least a 36% yield strength increase, and up to a 195%
yield strength increase, of the high strength material. In certain
other exemplary embodiments the high thermal conductivity material
and the high strength material are precipitation hardened together
at an aging temperature in the range of from 425.degree. C. to
480.degree. C., for up to 6 hours, to achieve at least a 96% yield
strength increase, and up to a 195% yield strength increase, of the
high strength material. In comparison, BeCu3 can be hardened at
these conditions to achieve a yield strength increase of up to at
least 404%, and an ultimate tensile strength increase of up to at
least 189%.
[0077] It is understood that, while the high thermal conductivity
material and the high strength material in the finished component
may be precipitation hardened under specific conditions and exhibit
measurable properties, the above description is with regard to the
general properties of the materials selected, and not necessarily
in all embodiments with regard to the characteristics of the
finished product. In other words, the above description refers to
the ability of the selected materials to be precipitation hardened
to achieve the stated properties, and not necessarily in all
embodiments to whether the selected materials actually are
processed in this manner or achieve the stated properties. Further,
description of the high thermal conductivity material and the high
strength material of a composite component as being precipitation
hardenable together (or as being precipitation hardenable together
under certain specified conditions) is a description of the
precipitation hardening properties of the materials in the
unhardened state. Thus, even if the materials are already
precipitation hardened, they may be described here as being
precipitation hardenable together (or as being precipitation
hardenable together under certain specified conditions) if they
would be precipitation hardenable together if they were in the
unhardened condition. The claims below should be interpreted in
this manner as well, unless clearly stated otherwise.
[0078] In producing the component disclosed herein, a first portion
formed of a high thermal conductivity material 66 and a second
portion formed of a high strength material 68 must first be
provided. In one embodiment, the first and second portions 66,68
are machined to the proper shapes from bar stock. In the nozzle tip
16 shown in FIG. 5, the first portion 66 constitutes a first piece
69A and the second portion 68 constitutes a second piece 69B, which
are both machined to create the body 60 having the flange 62 and
the bore 64. As described above, annealing prior to machining
softens the material and increases the machineability thereof.
Accordingly, in one embodiment, at least one of the first portion
66 and the second portion 68 is annealed prior to machining.
VascoMax.RTM. C300 and other VascoMax.RTM.(alloys, which are
suitable high strength materials 68, can be purchased in
pre-annealed form. Generally, VascoMax.RTM. C300 can be annealed at
830.degree. C. for 1 hour per inch of thickness to relieve stresses
and soften the material.
[0079] In certain exemplary embodiments, the high thermal
conductivity material may not be annealed prior to processing, and
may instead be provided in a pre-hardened condition. In accordance
with the principles disclosed here, however, the high thermal
conductivity material still would have the material property of
being precipitation hardenable from an unhardened state to a
hardened state under conditions applicable to precipitation
hardening of the high strength material with which it is integral
in the component The pre-hardened high thermal conductivity
material is provided with increased strength relative to an
unhardened condition. However, it is preferable that the high
thermal conductivity material does not overage during precipitation
hardening of the nozzle tip 16. Accordingly, in some exemplary
embodiments, the high thermal conductivity material at least
substantially maintains this increased strength during the
precipitation hardening. It is understood that, in some
embodiments, the pre-hardened high thermal conductivity material
may suffer decreased strength during the aging process, yet still
substantially maintain the increased strength provided by the
pre-hardening. In one exemplary embodiment, the pre-hardened high
thermal conductivity material maintains at least 90% of the
increased strength relative to the unhardened condition. In another
exemplary embodiment, the pre-hardened high thermal conductivity
material maintains at least 75% of the increased strength relative
to the unhardened condition. In one exemplary embodiment, the
pre-hardened high thermal conductivity material maintains at least
50% of the increased strength relative to the unhardened condition.
In one exemplary embodiment, the pre-hardened high thermal
conductivity material maintains at least 25% of the increased
strength relative to the unhardened condition. It is also
understood that, in some embodiments, in substantially maintaining
the increased strength, the pre-hardened high thermal conductivity
material may achieve a further strength increase relative to both
the unhardened and pre-hardened conditions during the aging
process. BeCu3, which is a suitable high thermal conductivity
material 66, is typically pre-hardened prior to machining, as
stated above. The pre-hardening can include fully or near-fully
hardening the material, such as by aging at 450.degree. C. for
three hours, or partially hardening the material, for example, by
decreasing the aging time or adjusting the aging temperature.
Alternately, the BeCu3 can be annealed at the same conditions as
VascoMax.RTM. C300 to relieve stresses and soften the material. In
additional embodiments, the first and second portions 66,68 can be
formed in different ways, such as by molding, powder metallurgy, or
other techniques known in the art.
[0080] In certain exemplary embodiments, once the high thermal
conductivity material portion and the high strength material
portion are formed in the proper shapes, they are integrally joined
using one of the techniques described above. For the nozzle tip 16
shown in FIG. 5, the two pieces 69 can be press-fit together prior
to joining. In certain exemplary embodiments, the first and second
portions are joined using electron beam ("EB") welding. Annealing
prior to processing, as described above, also provides benefits in
welding the high thermal conductivity material and the high
strength material together, such as reducing or preventing cracking
caused by the heat and resultant stresses of welding. BeCu3, listed
above as a suitable high conductivity material for at least certain
exemplary embodiments, can benefit from annealing prior to welding,
but such annealing is not necessary. For VascoMax.RTM. C300 and
other VascoMax.RTM. (alloys, listed above as suitable high strength
materials for at least certain exemplary embodiments, annealing
prior to welding typically is important, because there is a
significant risk of cracking when welding VascoMax.RTM. C300 in a
hardened condition. Certain other integral joining techniques may
benefit from annealing prior to further processing as well.
[0081] Optionally, in at least certain exemplary embodiments the
composite nozzle tip or other composite component disclosed here
may be annealed again after the high thermal conductivity material
and the high strength material portions are joined. Some joining
techniques, such as welding, can leave residual stresses in and
around the heat-affected zone (HAZ) of the weld. Annealing can
relieve these stresses, producing a part having more uniform stress
distribution and a lower risk of cracking during use. This
post-joining anneal can be generally performed as described above
for the pre-joining anneal.
[0082] After joining the high thermal conductivity material
portion(s) and the high strength material portion(s) of the
component, they are precipitation hardened as described above. This
precipitation hardening strengthens the high strength material and
the high thermal conductivity material, providing beneficial
properties in the finished component. In embodiments where the high
thermal conductivity material is pre-hardened, the high strength
material is strengthened through the precipitation hardening, and
the high thermal conductivity material at least substantially
maintains its increased strength relative to the unhardened
condition.
[0083] After the component is precipitation hardened, it can be
finish-machined to achieve desired tolerances and further shaping
of the component, and/or to achieve a desired finish on the surface
of the component.
[0084] In certain exemplary embodiments the precipitation hardened
component optionally can then be partially or completely coated
with a coating (including surface treatments in the nature of a
coating), e.g., to improve resistance to wear and corrosion. One
such desirable coating for at least certain embodiments is titanium
nitride (TiN), which provides excellent resistance to wear and
corrosion. Since titanium nitride can present adhesion problems,
the component can be plated via electroless nickel plating (ENP),
which allows the titanium nitride to adhere well to the component.
After plating, the titanium nitride coating can be created using
known techniques. In certain exemplary embodiments, the titanium
nitride coating can be created by physical vapor deposition (PVD),
which provides an effective coating and operates at an acceptably
low temperature so the properties of the high thermal conductivity
material and the high strength material are not significantly
adversely affected. In certain other embodiments, other techniques
could be used, such as chemical vapor deposition (CVD).
[0085] The operation and benefits of at least certain exemplary
embodiments of the composite nozzle tips and other composite
components disclosed here are now described with reference to
composite nozzle tips such as nozzle tips 16, e.g., the embodiment
illustrated in FIG. 5, used in a hot runner system 11, such as that
shown in FIG. 1, and an injection molding nozzle assembly 40, as
shown in FIGS. 2 and 2A. Material to be molded, for example a
polymer, is melted and fed into the hot runner system 11. The
molten material flows through the hot runner system 11 via the melt
channel 14, and flows into and through the nozzle assembly 40. In
the nozzle assembly 40, the heater 41 directly heats the nozzle
housing 12 and the tip retainer 24, which transfer heat to the
nozzle tip 16 and the molten material in the melt channel 14 and
the tip channel 22. As discussed above, enough heat must be
supplied to the nozzle tip 16 to open the gate at the beginning of
the injection cycle and keep it open during the injection process.
The tip 16 must not be so hot that it does not allow the gate to
freeze after packing is complete. The high thermal conductivity
material of the nozzle tip 16 assists in controlling the heat of
the nozzle tip 16. The nozzle tip 16 is positioned at the gate of
the mold cavity 38, and the molten material is injected from the
nozzle tip 16 into the mold cavity 38. The mold cavity 38 is
typically cooled, which causes the material to freeze quickly. The
flow of material from the nozzle tip 16 stops when the gate is
cooled and freezes. The high thermal conductivity material of the
nozzle tip 16 also assists in controlled freezing of the gate
proximate the tip 16.
[0086] Suitable embodiments of composite nozzle tips and other
composite components in accordance with this disclosure can provide
beneficial results when incorporated into a hot runner system for
an injection molding assembly. For example, nozzle tip 16 provides
excellent thermal conductivity, enhancing its ability to open and
close the mold gate during injection molding operations. The
composite structure of the nozzle tip 16 also results in greater
strength relative to certain prior existing nozzle tips, and
provides an advantageous combination of strength and thermal
conductivity. For example, at least certain previous nozzle tips
could only be used at pressures of up to 26 ksi (179 MPa). Suitable
embodiments of the nozzle tip 16 disclosed above can be used at
pressures of 35-40 ksi (241-275 MPa). Additionally, selecting the
high thermal conductivity material and the high strength material
to be precipitation hardenable together facilitates manufacturing
of the multi-piece nozzle tip. In particular, the pieces 69 used to
form the tip 16 can be machined and joined in a softened, annealed
condition and then precipitation hardened after assembly.
[0087] While the composite component is described above by way of
example as a nozzle tip 16 for a hot runner assembly 11, other
components of an injection molding assembly can benefit from the
composite construction and processing method described herein. For
example, FIG. 7 shows a composite nozzle tip retainer 124, similar
in structure and function to the nozzle tip retainers 24 shown in
FIGS. 1-4 and described above. The retainer 124 has a body 60
having threads 26 adapted for connection to a nozzle assembly 40,
the body 60 comprised of a first portion formed of a high thermal
conductivity material 66 and a second portion formed of a high
strength material 68, which are integrally joined together as
described above. Like the composite nozzle tip 16 described above,
the composite retainer 124 illustrated in FIG. 7 is manufactured
from two pieces 69A, 69B, having one piece 69A constituting the
portion formed of high thermal conductivity material 66 and the
other piece 69B constituting the second portion formed of high
strength material 68, and can be manufactured using the methods
described above. Also like the nozzle tip 16, the retainer 124 can
be designed or arranged differently, including being manufactured
from a different number of pieces 69. In this arrangement, the
retainer 124 will benefit from enhanced thermal conductivity around
the nozzle tip and enhanced strength and greater insulative
properties near the mold gate 38.
[0088] In another example, FIG. 8 shows a composite retainer plate
91 for a multi-probe nozzle assembly 84 such as that illustrated in
FIG. 9. The multi-probe nozzle assembly 84 has a multi-probe nozzle
body 80 and a plurality of nozzle tips 82 retained against the
nozzle body 80 by a retainer plate 91. The retainer plate 91 has a
body 60 comprised of a first portion formed of a high thermal
conductivity material 66 and a second portion formed of a high
strength material 68, which are integrally joined together as
described above. Like the composite nozzle tip 16 described above,
the composite retainer plate 91 is manufactured from two pieces
69A, 69B, having one piece 69A constituting the first portion
formed of high thermal conductivity material 66 and the other piece
69B constituting the second portion formed of high strength
material 68, and can be manufactured using the methods described
above. Also like the nozzle tip 16, the retainer plate 91 can be
designed or arranged differently, including being manufactured from
a different number of pieces 69. In this arrangement, the retainer
plate 91 will benefit from enhanced thermal conductivity near the
nozzles 82 and enhanced strength in a sealing-ring configuration
around the exterior of the retainer plate 91.
[0089] Another embodiment of a nozzle tip 16C is illustrated in
FIGS. 10-11. The nozzle tip 16C has a body 60 comprised of a first
portion formed of a high thermal conductivity material 66 and a
second portion formed of a high strength material 68, which are
integrally joined together as described above. A weld zone 67 is
indicated between the portions 66,68 in FIG. 11. The nozzle tip 16C
has a body 60 comprised of a flange 62 and a bore 64, and also has
a substantial extension piece 65 below the outlet openings 74 of
the tip 16C. As illustrated in FIG. 11, the second portion formed
of the high strength material 68 comprises the entire bore 64 and
flange 62, as well as a portion of the extension piece 65, and the
first portion formed of the high thermal conductivity material 66
forms only the end of the extension piece 65. Like the composite
nozzle tip 16 described above, the nozzle tip 16C is manufactured
from two pieces 69A, 69B, having one piece 69A constituting the
portion formed of high thermal conductivity material 66 and the
other piece 69B constituting the portion formed of high strength
material 68, and can be manufactured using the methods described
above. Also like the nozzle tip 16, the nozzle tip 16C can be
designed or arranged differently, including being manufactured from
a different number of pieces 69. In this arrangement, the nozzle
tip 16C will benefit from enhanced thermal conductivity near the
mold gate and enhanced strength in the sealing region of the tip
16C.
[0090] A further embodiment of a nozzle tip 16D is illustrated in
FIG. 12. The nozzle tip 16D has a body 60 comprised of a first
portion formed of a high thermal conductivity material 66 and a
second portion formed of a high strength material 68, which are
integrally joined together as described above. The nozzle tip 16D
has a flange 62 and a bore 64. As illustrated in FIG. 12, the
second portion formed of the high strength material 68 comprises
the entire bore 64 and flange 62, and the first portion formed of
the high thermal conductivity material 66 forms only the very tip
of the nozzle tip 16D. Like the composite nozzle tip 16 described
above, the nozzle tip 16D is manufactured from two pieces 69A, 69B,
having one piece 69A constituting the portion formed of high
thermal conductivity material 66 and the other piece 69B
constituting the portion formed of high strength material 68, and
can be manufactured using the methods described above. Also like
the nozzle tip 16, the nozzle tip 16D can be designed or arranged
differently, including being manufactured from a different number
of pieces 69. In this arrangement, the nozzle tip 16D will benefit
from enhanced thermal conductivity near the mold gate and enhanced
strength in the sealing region of the tip 16D.
[0091] FIG. 18 illustrates another embodiment of a nozzle tip 16F.
The nozzle tip 16F has a body 60 comprised of a first portion
formed of a high thermal conductivity material 66 and a second
portion formed of a high strength material 68, which are integrally
joined together as described above. The nozzle tip 16F has a body
60 comprised of a flange 62 and a bore 64 that leads to two outlet
openings 74 near the end 76 of the tip 16F. As illustrated in FIG.
18, the first portion formed of the high thermal conductivity
material 66 surrounds the entire bore 64 of the tip 16F, and the
second portion formed of the high strength material 68 comprises
the flange 62 and forms a shell around the high thermal
conductivity material 66 extending substantially the entire length
of the tip 16F, nearly to the outlet end 76. Like the composite
nozzle tip 16 described above, the nozzle tip 16F is manufactured
from two pieces 69A, 69B, having one piece 69A constituting the
portion formed of high thermal conductivity material 66 and the
other piece 69B constituting the portion formed of high strength
material 68, and can be manufactured using the methods described
above. In the embodiment shown in FIG. 18, the two pieces 69A, 69B
may be integrally joined by welding only at an area proximate to
the outlet end 76, shown by weld zones 67. Because the pieces 69A,
69B are not joined at the inlet end 72, greater freedom for thermal
expansion at that end 72 is permitted. Also like the nozzle tip 16,
the nozzle tip 16F can be designed or arranged differently,
including being manufactured from a different number of pieces 69,
or by integrally joining in another manner. In this arrangement,
the nozzle tip 16F will benefit from enhanced thermal conductivity
near the mold gate and around the bore 64 and enhanced strength in
the sealing region of the tip 16F.
[0092] FIG. 19 illustrates a blank 90F used in manufacturing the
nozzle tip 16F shown in FIG. 18. The blank 90F is comprised of a
first piece 69A constituting the portion formed of high thermal
conductivity material 66 and a second piece 69B constituting the
portion formed of high strength material 68. As described above,
the pieces 69A, 69B are machined to desired shapes and dimensions
and are then integrally joined together, such as by EB welding, to
form the blank 90F shown in FIG. 19. This EB welding creates weld
zones 67 between the pieces 69A, 69B, as described above. The blank
90F is then finish machined to create the shape of the nozzle tip
16F shown in FIG. 18, including creating the bore 64 and outlet
openings 74 in the body 60.
[0093] FIG. 20 illustrates another embodiment of a nozzle tip 16G.
The nozzle tip 16G has a body 60 comprised of a first portion
formed of a high thermal conductivity material 66 and a second
portion formed of a high strength material 68, which are integrally
joined together as described above. The nozzle tip 16G has a body
60 comprised of a flange 62 and a bore 64 that leads to two outlet
openings 74 near the end 76 of the tip 16G. As illustrated in FIG.
20, the first portion formed of the high thermal conductivity
material 66 surrounds the entire bore 64 and forms the outlet end
76 of the tip 16G, and the second portion formed of the high
strength material 68 comprises the flange 62 and forms a shell
around the high thermal conductivity material 66 extending slightly
less than the entire length of the tip 16G. Like the composite
nozzle tip 16 described above, the nozzle tip 16G is manufactured
from two pieces 69A, 69B, having one piece 69A constituting the
portion formed of high thermal conductivity material 66 and the
other piece 69B constituting the portion formed of high strength
material 68, and can be manufactured using the methods described
above. In the embodiment shown in FIG. 20, the two pieces 69A, 69B
may be integrally joined by welding only at an area nearest the
outlet end 76, shown by weld zones 67. Because the pieces 69A, 69B
are not joined at the inlet end 72, greater freedom for thermal
expansion at that end 72 is permitted. Also like the nozzle tip 16,
the nozzle tip 16G can be designed or arranged differently,
including being manufactured from a different number of pieces 69,
or by integrally joining in another manner. In this arrangement,
the nozzle tip 16G will benefit from enhanced thermal conductivity
near the mold gate and around the bore 64 and enhanced strength in
the sealing region of the tip 16G.
[0094] FIG. 21 illustrates a blank 90G used in manufacturing the
nozzle tip 16F shown in FIG. 20. The blank 90G is comprised of a
first piece 69A constituting the portion formed of high thermal
conductivity material 66 and a second piece 69B constituting the
portion formed of high strength material 68. As described above,
the pieces 69A, 69B are machined to desired shapes and dimensions
and are then integrally joined together, such as by EB welding, to
form the blank 90G shown in FIG. 19. EB welding creates weld zones
67 between the pieces 69A, 69B. The blank 90G is then finish
machined to create the shape of the nozzle tip 16G shown in FIG.
20, including creating the bore 64 and outlet openings 74 in the
body 60.
[0095] FIG. 22 illustrates another embodiment of a nozzle tip 16H.
The nozzle tip 16H has a body 60 comprised of a first portion
formed of a high thermal conductivity material 66 and a second
portion formed of a high strength material 68, which are integrally
joined together as described above. A weld zone 67 is indicated
between the portions 66,68. The nozzle tip 16H has a body 60
comprised of a flange 62 and a bore 64 that leads to two outlet
openings 74 near the end 76 of the tip 16H. As illustrated in FIG.
22, the first portion formed of the high thermal conductivity
material 66 surrounds the entire bore 64 and forms the bulk of the
body 60 of the tip 16H, and the second portion formed of the high
strength material 68 comprises the flange 62 and forms a shell
around the high thermal conductivity material 66 extending slightly
away from the flange 62. Like the composite nozzle tip 16 described
above, the nozzle tip 16H is manufactured from two pieces 69A, 69B,
having one piece 69A constituting the portion formed of high
thermal conductivity material 66 and the other piece 69B
constituting the portion formed of high strength material 68, and
can be manufactured using the methods described above. Also like
the nozzle tip 16, the nozzle tip 16H can be designed or arranged
differently, including being manufactured from a different number
of pieces 69, or by integrally joining in another manner. In this
arrangement, the nozzle tip 16H will benefit from enhanced thermal
conductivity near the mold gate and around the bore 64 and enhanced
strength in the sealing region of the tip 16H.
[0096] FIG. 23 illustrates a blank 90H used in manufacturing the
nozzle tip 16H shown in FIG. 22. The blank 90H is comprised of a
first piece 69A constituting the portion formed of high thermal
conductivity material 66 and a second piece 69B constituting the
portion formed of high strength material 68. As described above,
the pieces 69A, 69B are machined to desired shapes and dimensions
and are then integrally joined together, such as by EB welding, to
form the blank 90H shown in FIG. 19. EB welding creates weld zones
67 between the pieces 69A, 69B. The blank 90H is then finish
machined to create the shape of the nozzle tip 16H shown in FIG.
22, including creating the bore 64 and outlet openings 74 in the
body 60.
[0097] FIG. 24 illustrates another embodiment of a nozzle tip 16I.
The nozzle tip 16I has a body 60 comprised of a first portion
formed of a high thermal conductivity material 66 and a second
portion formed of a high strength material 68, which are integrally
joined together as described above. A weld zone 67 is indicated
between the portions 66,68. The nozzle tip 16I has a body 60
comprised of a flange 62 and a bore 64 that leads to two outlet
openings 74 near the end 76 of the tip 16I. As illustrated in FIG.
24, the first portion formed of the high thermal conductivity
material 66 surrounds nearly the entire bore 64 and forms the bulk
of the body 60 of the tip 16I, and the second portion formed of the
high strength material 68 comprises the flange 62 and a cap on the
inlet end 72 of the tip 16I. In contrast to the embodiments
described above, the nozzle tip 16I is manufactured from three
pieces 69A, 69B, 69C having one piece 69A constituting the portion
formed of high thermal conductivity material 66 and two pieces 69B,
69C joining to form the portion formed of high strength material
68. One of the high strength material pieces 69B forms the flange
62 and the other high strength material piece 69C forms the cap on
the inlet end 72. The three-piece nozzle tip 16I can be
manufactured using the methods described above, except that three
pieces 69 will be joined together instead of two. Also, like the
nozzle tip 16, the nozzle tip 16I can be designed or arranged
differently, including being manufactured from a different number
of pieces 69, or by integrally joining in another manner. In this
arrangement, the nozzle tip 16I will benefit from enhanced thermal
conductivity near the mold gate and around the bore 64 and enhanced
strength in the sealing region of the tip 16I.
[0098] FIG. 25 illustrates a portion of a blank 90I used in
manufacturing the nozzle tip 16I shown in FIG. 24. The blank 90I is
comprised of a first piece 69A constituting the portion formed of
high thermal conductivity material 66 and a second piece 69B and a
third piece 69C constituting the portion formed of high strength
material 68. As described above, the pieces 69A, 69B, 69C are
machined to desired shapes and dimensions and are then assembled
and integrally joined together, such as by EB welding, to form the
blank 90I shown in FIG. 25. EB welding creates weld zones 67
between the pieces 69A, 69B, 69C. The blank 90I is then finish
machined to create the shape of the nozzle tip 16I shown in FIG.
25, including creating the bore 64 and outlet openings 74 in the
body 60.
[0099] FIG. 26 illustrates another embodiment of a nozzle tip 16J.
The nozzle tip 16J has a body 60 comprised of a first portion
formed of a high thermal conductivity material 66 and a second
portion formed of a high strength material 68, which are integrally
joined together as described above. A weld zone 67 is indicated
between the portions 66,68. The nozzle tip 16J has a body 60
comprised of a flange 62 and a bore 64 that leads to two outlet
openings 74 near the end 76 of the tip 16J. As illustrated in FIG.
26, the first portion formed of the high thermal conductivity
material 66 surrounds nearly the entire bore 64 and forms the bulk
of the body 60 of the tip 16J, and the second portion formed of the
high strength material 68 comprises the flange 62 and a cap on the
inlet end 72 of the tip 16J. In contrast to the embodiments
described above, and similarly to the embodiment of FIGS. 24-25,
the nozzle tip 16J is manufactured from three pieces 69A, 69B, 69C
having one piece 69A constituting the portion formed of high
thermal conductivity material 66 and two pieces 69B, 69C joining to
form the portion formed of high strength material 68. One of the
high strength material pieces 69B forms the flange 62 and the other
high strength material piece 69C forms the cap on the inlet end 72.
The three-piece nozzle tip 16J can be manufactured using the
methods described above, except that three pieces 69 will be joined
together instead of two. Also, like the nozzle tip 16, the nozzle
tip 16J can be designed or arranged differently, including being
manufactured from a different number of pieces 69, or by integrally
joining in another manner. In this arrangement, the nozzle tip 16J
will benefit from enhanced thermal conductivity near the mold gate
and around the bore 64 and enhanced strength in the sealing region
of the tip 16J.
[0100] FIG. 27 illustrates a portion of a blank 90J used in
manufacturing the nozzle tip 16J shown in FIG. 26. The blank 90J is
comprised of a first piece 69A constituting the portion formed of
high thermal conductivity material 66 and a second piece 69B and a
third piece 69C constituting the portion formed of high strength
material 68. As described above, the pieces 69A, 69B, 69C are
machined to desired shapes and dimensions and are then assembled
and integrally joined together, such as by EB welding, to form the
blank 90J shown in FIG. 27. EB welding creates weld zones 67
between the pieces 69A, 69B, 69C. The blank 90J is then finish
machined to create the shape of the nozzle tip 16J shown in FIG.
25, including creating the bore 64 and outlet openings 74 in the
body 60.
[0101] Still further components of an injection molding assembly 10
can be produced using the method and composite structure described
herein, incorporating a high thermal conductivity material 66 and a
high strength material 68 integrally joined together. In accordance
with the principles disclosed here, the high thermal conductivity
material and the high strength material are precipitation
hardenable from an unhardened state to a hardened state under the
same conditions, as described above. In other examples, the
component could be a sprue bushing, a manifold bushing, a sprue
bar, one of various components of a conveying system, a machine
nozzle, a mold cavity, or another component of the nozzle assembly
40. FIG. 13 illustrates an exemplary embodiment of a hot runner
assembly 111 for an injection molding assembly 110 that includes
both a hot-tip style nozzle assembly 140 and a valve-gate style
nozzle assembly 240. The hot runner assembly 111 includes a melt
channel 114 that flows through a sprue bushing 190 to a manifold
132 and then splits into a first melt channel 114A and a second
melt channel 114B. The first melt channel 114A flows from the
manifold 132 to the hot-tip nozzle assembly 140 and into a first
mold cavity 138. The second melt channel 114B flows through a
manifold bushing 192 and the valve-gate nozzle assembly 240 to
enter a second mold cavity 238 through a gate insert 298. Each mold
cavity 138, 238 is defined by a mold cavity insert 194, 294 and a
core insert 196, 296 lining the respective mold cavity 138, 238.
Each nozzle assembly 140, 240 has a nozzle housing 112, 212 that is
connected to a nozzle tip 116, 216. Various components of the hot
runner assembly 111 illustrated in FIG. 13 can be manufactured
according to the method and composite structure defined herein,
including the sprue bushing 190, the manifold bushing 192, the
nozzle housings 112, 212, the gate insert 298, the cavity inserts
194, 294, and the core inserts 196, 296, as described below. Of
course, the nozzle tips 116, 216 may also be manufactured in this
manner, as described herein.
[0102] FIG. 14 illustrates a sprue bushing 190 as shown in FIG. 13,
having a body 160A comprised of a first portion formed of a high
thermal conductivity material 66 and a second portion formed of a
high strength material 68, which are integrally joined together as
described above. In accordance with the principles disclosed here,
the high thermal conductivity material and the high strength
material are precipitation hardenable from an unhardened state to a
hardened state under the same conditions, as described above. The
high thermal conductivity material 66 is positioned proximate the
melt channel 114 for supplying heat thereto, and the high strength
material 68 is positioned in areas where greater structural
integrity is desirable. Like the composite nozzle tip 16 described
above, the sprue bushing 190 is manufactured from two pieces 69A,
69B, having one piece 69A constituting the portion formed of high
thermal conductivity material 66 and the other piece 69B
constituting the portion formed of high strength material 68, and
can be manufactured using the methods described above. Also like
the nozzle tip 16, the sprue bushing 190 can be designed or
arranged differently, including being manufactured from a different
number of pieces 69. In this arrangement, the sprue bushing 190
will benefit from enhanced thermal conductivity near the melt
channel 114 and enhanced strength in other regions.
[0103] FIG. 15 illustrates a manifold bushing 192 as shown in FIG.
13, having a body 160B comprised of a first portion formed of a
high thermal conductivity material 66 and a second portion formed
of a high strength material 68, which are integrally joined
together as described above. In accordance with the principles
disclosed here, the high thermal conductivity material and the high
strength material are precipitation hardenable from an unhardened
state to a hardened state under the same conditions, as described
above. The high thermal conductivity material 66 is positioned
proximate the melt channel 114 for supplying heat thereto, and the
high strength material 68 is positioned in areas where greater
structural integrity is desirable. Like the composite nozzle tip 16
described above, the manifold bushing 192 is manufactured from two
pieces 69A, 69B, having one piece 69A constituting the portion
formed of high thermal conductivity material 66 and the other piece
69B constituting the portion formed of high strength material 68,
and can be manufactured using the methods described above. Also
like the nozzle tip 16, the manifold bushing 192 can be designed or
arranged differently, including being manufactured from a different
number of pieces 69. In this arrangement, the manifold bushing 192
will benefit from enhanced thermal conductivity near the melt
channel 114 and enhanced strength in other regions.
[0104] FIG. 16 illustrates a nozzle assembly 240 as shown in FIG.
13, which includes a nozzle housing 212 having a body 160C
comprised of a first portion formed of a high thermal conductivity
material 66 and a second portion formed of a high strength material
68, which are integrally joined together as described above. In
accordance with the principles disclosed here, the high thermal
conductivity material and the high strength material are
precipitation hardenable from an unhardened state to a hardened
state under the same conditions, as described above. The high
thermal conductivity material 66 is positioned proximate the melt
channel 114 for supplying heat thereto, and the high strength
material 68 is positioned in areas where greater structural
integrity is desirable. Like the composite nozzle tip 16 described
above, the nozzle housing 212 is manufactured from two pieces 69A,
69B, having one piece 69A constituting the portion formed of high
thermal conductivity material 66 and the other piece 69B
constituting the portion formed of high strength material 68, and
can be manufactured using the methods described above. Also like
the nozzle tip 16, the nozzle housing 212 can be designed or
arranged differently, including being manufactured from a different
number of pieces 69. In this arrangement, the nozzle housing 212
will benefit from enhanced thermal conductivity near the melt
channel 114 and enhanced strength in other regions, including
sealing regions.
[0105] FIG. 16 also illustrates a gate insert 298 as shown in FIG.
13, having a body 160D comprised of a first portion formed of a
high thermal conductivity material 66 and a second portion formed
of a high strength material 68, which are integrally joined
together as described above. In accordance with the principles
disclosed here, the high thermal conductivity material and the high
strength material are precipitation hardenable from an unhardened
state to a hardened state under the same conditions, as described
above. The gate insert 298 has a passage 297 that permits the
nozzle tip 216 to access the mold cavity 238. The high thermal
conductivity material 66 is positioned around the passage 297,
proximate the nozzle tip 216 and the melt channel 114 for
conducting heat thereto and/or therefrom, and the high strength
material 68 is positioned in areas where greater structural
integrity is desirable. Like the composite nozzle tip 16 described
above, the gate insert 298 is manufactured from two pieces 69A,
69B, having one piece 69A constituting the portion formed of high
thermal conductivity material 66 and the other piece 69B
constituting the portion formed of high strength material 68, and
can be manufactured using the methods described above. Also like
the nozzle tip 16, the gate insert 298 can be designed or arranged
differently, including being manufactured from a different number
of pieces 69. In this arrangement, gate insert 298 will benefit
from enhanced thermal conductivity near the nozzle tip 216 and the
melt channel 114 and enhanced strength in other regions, including
sealing regions.
[0106] FIG. 17 illustrates a cavity insert 194 as shown in FIG. 13,
having a body 160E comprised of a first portion formed of a high
thermal conductivity material 66 and a second portion formed of a
high strength material 68, which are integrally joined together as
described above. In accordance with the principles disclosed here,
the high thermal conductivity material and the high strength
material are precipitation hardenable from an unhardened state to a
hardened state under the same conditions, as described above. The
cavity insert 194 is adapted to define the injection molding cavity
138. The high thermal conductivity material 66 is positioned
proximate the mold cavity 138 and the nozzle tip 116 for conducting
heat thereto and therefrom, and the high strength material 68 is
positioned in areas where greater structural integrity is
desirable. Like the composite nozzle tip 16 described above, the
cavity insert 194 is manufactured from two pieces 69A, 69B, having
one piece 69A constituting the portion formed of high thermal
conductivity material 66 and the other piece 69B constituting the
portion formed of high strength material 68, and can be
manufactured using the methods described above. Also like the
nozzle tip 16, the cavity insert 194 can be designed or arranged
differently, including being manufactured from a different number
of pieces 69. In this arrangement, the cavity insert 194 will
benefit from enhanced thermal conductivity near the mold cavity 138
and nozzle tip 116 and enhanced strength in other regions.
[0107] FIG. 17 also illustrates a core insert 196 as shown in FIG.
13, having a body 160F comprised of a first portion formed of a
high thermal conductivity material 66 and a second portion formed
of a high strength material 68, which are integrally joined
together as described above. In accordance with the principles
disclosed here, the high thermal conductivity material and the high
strength material are precipitation hardenable from an unhardened
state to a hardened state under the same conditions. The core
insert 196 is adapted to define the injection molding cavity 138,
in combination with the cavity insert 194. The high thermal
conductivity material 66 is positioned proximate the mold cavity
138 and the nozzle tip 116 for conducting heat thereto and
therefrom, and the high strength material 68 is positioned in areas
where greater structural integrity is desirable. Like the composite
nozzle tip 16 described above, the core insert 196 is manufactured
from two pieces 69A, 69B, having one piece 69A constituting the
portion formed of high thermal conductivity material 66 and the
other piece 69B constituting the portion formed of high strength
material 68, and can be manufactured using the methods described
above. Also like the nozzle tip 16, the core insert 196 can be
designed or arranged differently, including being manufactured from
a different number of pieces 69. In this arrangement, the core
insert 196 will benefit from enhanced thermal conductivity near the
mold cavity 138 and nozzle tip 116 and enhanced strength in other
regions.
[0108] Other components used as examples suitable for use with the
composite high thermal conductivity material 66 and high strength
material 68 described herein can be incorporated and used in ways
known in the art. The composite structure provides benefits similar
to those described herein, such as providing good thermal
conductivity in combination with enhanced strength where necessary
or advantageous.
[0109] Several alternative embodiments and examples have been
described and illustrated herein. A person of ordinary skill in the
art, given the benefit of this disclosure, will appreciate the
features of the individual embodiments, and all of the suitable
combinations and variations of the components. A person of ordinary
skill in the art, given the benefit of this disclosure, will
further appreciate that any of the embodiments can be provided in
any combination with the other embodiments disclosed herein. It is
understood that the invention may be embodied in other specific
forms without departing from the spirit or central characteristics
thereof. The present examples and embodiments, therefore, are to be
considered in all respects as illustrative and not restrictive, and
the invention is not to be limited to the details given herein. The
terms "first," "second," etc., as used herein, are intended for
illustrative purposes only, or for convenient reference, and do not
limit the embodiments in any way. Additionally, the term
"plurality," as used herein, indicates any number greater than one,
either disjunctively or conjunctively, as necessary. Accordingly,
while the specific embodiments have been illustrated and described,
numerous modifications come to mind without significantly departing
from the spirit of the invention and the scope of protection is
only limited by the scope of the accompanying claims.
* * * * *