U.S. patent application number 15/104868 was filed with the patent office on 2016-12-29 for method for producing a casting core and a casting core.
This patent application is currently assigned to Daimler AG. The applicant listed for this patent is Daimler AG. Invention is credited to Paul FICKEL, Reinhard HOLL, Hermann PFEIFER, Michael SCHEYDECKER, Karl WEISSKOPF.
Application Number | 20160375484 15/104868 |
Document ID | / |
Family ID | 52102638 |
Filed Date | 2016-12-29 |
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United States Patent
Application |
20160375484 |
Kind Code |
A1 |
FICKEL; Paul ; et
al. |
December 29, 2016 |
Method for Producing a Casting Core and a Casting Core
Abstract
A method for the production of a casting core is provided. The
method includes preparing a mold which has at least one cavity and
at least one filling opening which is fluidically connected to the
cavity, introducing a liquid, hardenable salt molding material into
the cavity via the filling opening, and at least partial hardening
of the salt molding material introduced into the cavity to form a
hollow body produced from hardened salt molding material, the
hollow body having at least one hollow space of the casting core
which is delimited by the hardened salt molding material. The
hollow space of the casting core is closed on all sides by means of
the salt molding material introduced into the cavity. A casting
core is also provided.
Inventors: |
FICKEL; Paul;
(Pfaffenhausen, DE) ; HOLL; Reinhard; (Lauingen,
DE) ; PFEIFER; Hermann; (Essingen, DE) ;
SCHEYDECKER; Michael; (Nersingen, DE) ; WEISSKOPF;
Karl; (Rudersberg, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Daimler AG |
Stuttgart |
|
DE |
|
|
Assignee: |
Daimler AG
Stuttgart
DE
|
Family ID: |
52102638 |
Appl. No.: |
15/104868 |
Filed: |
December 5, 2014 |
PCT Filed: |
December 5, 2014 |
PCT NO: |
PCT/EP2014/003268 |
371 Date: |
June 15, 2016 |
Current U.S.
Class: |
164/369 |
Current CPC
Class: |
B22C 1/00 20130101; B22C
21/14 20130101; B22C 9/105 20130101 |
International
Class: |
B22C 9/10 20060101
B22C009/10 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 17, 2013 |
DE |
10 2013 021 197.2 |
Claims
1.-9. (canceled)
10. A method for the production of a casting core, the method
comprising the steps of: preparing a mold which has at least one
cavity and at least one filling opening which is fluidically
connected to the cavity; introducing a liquid, hardenable salt
molding material into the cavity via the filling opening; and at
least partial hardening of the salt molding material introduced
into the cavity to form a hollow body produced from hardened salt
molding material, the hollow body having at least one hollow space
of the casting core which is delimited by the hardened salt molding
material, and wherein the hollow space of the casting core is
closed on all sides by means of the salt molding material
introduced into the cavity.
11. The method according to claim 10, wherein after the step of at
least partial hardening, a still liquid first part of the salt
molding material introduced into the cavity is led away from the
hollow space via the filling opening and the hollow space is closed
at least in the region of the filling opening by means of a still
liquid second part of the salt molding material introduced into the
cavity by hardening of the second part of the hollow space.
12. The method according to claim 11, wherein a cross section of
the filling opening is more than double the wall thickness of the
hardened salt molding material which delimits the hollow space.
13. The method according to claim 10, wherein after closing the
hollow space, the casting core is moved around at least one axis,
whereby a still liquid part of the salt molding material located in
the hollow space is spread along the hollow body and hardened.
14. The method according to claim 10, wherein at least one core
mounting protruding from the hollow body is produced in a casting
mold from the salt molding material and by means of the mold for
mounting the casting core.
15. The method according to claim 14, wherein the core mounting is
formed to be solid at least in a partial region.
16. The method according to claim 10, wherein the casting core is
cast to be near-net-shape with a tolerance in a range from 0.1 to
0.5 millimeters, and is removed from the mold.
17. The method according to claim 10, further comprising using of
the produced casting core in a die casting method.
18. The method according to claim 17, wherein the die casting
method is an aluminum die casting method.
19. The method according to claim 10, wherein the casting core is
for metal casting.
20. A casting core comprising: a hollow body formed of a salt
molding material, the hollow body having at least one hollow space
which is delimited by the hardened salt molding material, and
wherein the hollow space is closed on all sides by the hardened
salt molding material.
21. The casting core according to claim 20, wherein the casting
core is used in a die casting method.
22. The casting core according to claim 21, wherein the die casting
method is an aluminum die casting method.
23. The casting core according to claim 20, wherein the casting
core is for metal casting.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
[0001] The invention relates to a method for the production of a
casting core, in particular for metal casting, as well as a casting
core, in particular for metal casting.
[0002] In casting technology, it has been shown that hollow die
casting parts, in particular hollow aluminum die casting parts,
having low wall strengths with the aid of lost core setters often
cannot be automatically produced to be dimensionally stable, in
particular due to lacking core mounting and handling concepts. Such
hollow aluminum components are, however, advantageous in that they
are light and they are quick and cost-effective to produce.
[0003] It has been shown that the use of sand cores is not
expedient since they are not suitable with regard to strength,
surface quality and dimensional stability for the production of
thin-walled, complex components, in particular structural
components for vehicle construction. Furthermore, high pressures
should be observed when using casting cores in the die casting
method, with which high pressures the liquid casting material is
introduced into the die casting mold, in which at least one casting
core is located. These high pressures, which can be up to 800 bar,
subject the casting core to high loads during die casting which a
sand core cannot withstand.
[0004] A method for the production of a casting core, in particular
for metal casting, as well as such a casting core, can be taken as
known from DE 10 2012 022 102 A1. A mold is provided for the method
which has at least one cavity and at least one filling opening
which is fluidically connected to the cavity. A liquid, hardenable
salt molding material is introduced into the cavity via the filling
opening; the casting core is thus a cast salt core. The salt
molding material introduced into the cavity is at least partially
hardened, such that a hollow body produced from the hardened salt
molding material having at least one hollow space of the casting
core delimited by the hardened salt molding material results.
[0005] In this known method, the casting core still has one opening
after the hardening of the salt molding material in the region of
the filling opening, the opening leading on one side into the
hollow space and on the other side into the surroundings of the
casting core. In a further step, the casting core or its hollow
space is filled with a solid granulate or a solid powder, by means
of which the opening is closed. Alternatively, the hollow space is
filled with a fluid. The opening is closed by filling the hollow
space with the granulate or fluid such that no liquid casting
material can enter into the hollow space of the casting core during
the die casting method. However, filling the hollow space and the
closing of the opening caused by this represent an additional
process step which is usually required, however, in order to seal
the hollow space.
[0006] A suitable salt molding material for the production of a
lost casting core in a die casting method is, for example, known
from EP 2 647 451 A1.
[0007] Finally, DE 10 2011 105 389 A1 discloses a casting tool, in
particular for the production of a cylinder crankhouse of a
combustion engine. The casting tool includes a first part of a die
casting mold of the casting tool and a core arranged on the first
part, the core being positioned on the first part by a fixed
bearing. It is thereby provided that the core is positioned on the
first part by an additional floating bearing to balance thermal
expansions of the core.
[0008] The object of the present invention is therefore to create a
method and a casting core of the type cited above, by means of
which a particularly simple, quick and cost-effective production of
the casting core can be achieved.
[0009] In order to create a method for the production of a casting
core, by means of which a particularly simple, quick and
cost-effective production of the casting core can be achieved, it
is provided according to the invention that the hollow space of the
casting core is closed on all sides by means of the molding
material introduced into the cavity. By means of the method
according to the invention, it is thus possible to produce a
completely closed hollow casting core having a defined wall
strength by casting, wherein the hollow casting core, i.e., the
casting core, can be produced without separate sealing measures to
be sealed for die casting and, for example, can be cast around as a
lost core in a die casting tool, in particular in an aluminum die
casting tool without a liquid casting material, which is introduced
into the die casting tool, entering into the hollow space of the
casting core. Since the hollow space is closed on all sides, i.e.,
completely, by means of the salt molding material, the hollow space
of the casting core must not be filled with a material or liquid
which is different from the salt molding material. The time and
material requirements for the production of the casting core can
thereby be kept particularly low. Since the casting core is
produced with a large volume and hollowly as a cast salt core for
die casting, in particular for aluminum die casting, on one hand, a
large hollow space can be achieved in a casting component, in
particular in an aluminum casting component by means of the casting
core. On the other hand, the hollow, cast salt core has the
advantage that it can be produced with a low molding material
requirement. Furthermore, in comparison to a solid casting core,
only a small amount of salt must be washed out of the die casting
component after casting. A further advantage is that the core of
the cast die casting component can be removed in a particularly
simple manner since the casting core is soluble in water as a
result of it being produced from salt. The casting core can thereby
be washed out of the die casting component in a simple manner using
water after producing the die casting component.
[0010] Since the hollow space is completely closed, the hollow body
has a completely closed crust with a defined wall strength. A high
compressive strength of the core can be ensured by correspondingly
adjusting the wall thickness of the salt crust, such that the
casting core can, for example, also bear high pressures during die
casting without damage occurring. A further advantage of the
completely closed crust is that the casting core can be used
directly as a die casting core. This means that, after producing
the casting core, no further processing steps are required, in
particular, to close the hollow space. The only possible reworking
required consists in separating undesired or unnecessary casting
runners from the hollow body. Moreover, the casting core can be
cast to be near-net-shape, in particular with a tolerance in a
range from 0.1 to 0.5 millimeters and removed from the mold. This
tolerance range from 0.1 millimeters inclusive to 0.5 millimeters
inclusive thereby relates to the deviation of the end contour of
the cast casting core from an ideal contour, for example, according
to the design drawing of the casting core. This means that the
casting core can be used as a casting core in a casting mold, in
particular a die casting mold after its production without
subsequent surface treatments.
[0011] It has been shown to be furthermore advantageous when still
liquid salt molding material, i.e., a liquid molten material from
the salt molding material, and a high pressure are maintained
during cooling and during hardening of the salt molding material in
the hollow space. As a result, the danger of cracks arising in the
crust during cooling when producing the casting core by shrinkage
is kept particularly low. This embodiment is based on the knowledge
that salts have a very high thermal expansion. The thermal
expansion can be approximately twice as high as the thermal
expansion of aluminum. Fine hairline cracks arising during cooling
by shrinkage are uncritical at first. However, during die casting,
in particular during aluminum die casting, pressures of up to 800
bar act on the casting core, wherein hairline cracks represent
potential breaking points. However, the risk of cracks arising can
be kept low by holding liquid molten material in the hollow space
and by adjusting a high pressure in the hollow space during
hardening.
[0012] In the context of the method, the casting core is, for
example, moved by means of a gripper of a robot, preferably
three-dimensionally, in order to achieve an at least substantially
even wall strength of the hollow body. For this purpose, the mold,
by means of which the casting core is produced, can be moved.
Alternatively, it is possible to remove and move the casting core
out of the mold by means of a gripper.
[0013] In the context of the method, it can be provided that the
liquid salt molding material can be introduced into the mold and
held there for 10 seconds, at approximately 700 degrees Celsius and
approximately 50 degrees above the solidus temperature of the salt
molding material. The subsequent molding of the casting core lasts
for approximately 45 to 120 seconds. The molding preferably lasts
for a maximum of 120 seconds. It has been shown, in particular,
that in the event of a longer molding duration, the casting core
can crack due to shrinkage constraint. If the casting core or its
hollow body has a high wall strength, i.e., if the hollow body is
formed as a particularly thick shell, then the casting core has
particularly high heat isolation.
[0014] Hollow aluminum die casting components can be produced by
means of the casting core, wherein such hollow aluminum die casting
components are particularly light. The production of such aluminum
die casting components can thereby be achieved in a cost-effective
manner by means of the casting core.
[0015] Sand cores are usually used to produce hollow spaces in
aluminum components. However, these do not withstand the high
pressures during die casting. However, in order to be able to
produce particularly thin-walled components which are light and
thus are used in particular as structural components in vehicle
construction, die casting must be used. Salt cores are particularly
advantageous as casting cores for use in aluminum die casting since
they have a good, i.e., even, surface and high stability. However,
these salt cores are required to be able to be removed in a simple
manner from the produced aluminum die casting component and to be
able to be produced in a cost-effective manner.
[0016] It is thereby known to produce salt cores from pure sodium
chloride (NaCl), wherein these salt cores are produced by pressing
and baking. However, these salt cores only have a limited load
capacity, such that they can carry damage when used in a die
casting method.
[0017] A higher load capacity can be achieved with cast salt cores.
The method according to the invention now enables particularly
cost-effective production of a cast salt core since additional
sealing measures to close the hollow space can be avoided at least
in the region of the filling opening. For example, it is possible
to use a casting core produced according to the method according to
the invention for the production of crankcases, in particular
cylinder bridge cooling systems for crankcases. It is furthermore
conceivable to produce support elements such as, for example, a
cross member of a passenger car body by means of such a hollow cast
salt core.
[0018] Furthermore, the method according to the invention enables
the depiction of a highly productive, fully automated aluminum die
casting process for complex aluminum die casting components with
undercuts or hollow structures which, up until now, have only been
able to be produced by means of gravity casting. As a result of the
hollow space being closed at least in the region of the filling
opening by means of the salt molding material introduced into the
cavity, a fully automated production process can be achieved for
the production of such casting cores. At the same time, the
advantages of aluminum die casting remain intact over aluminum
gravity casting, sand and chill casting. Compared to gravity, sand
and chill casting, components are able to be produced considerably
more cheaply and with a lower wall thickness by aluminum die
casting. In particular, it is possible to produce wall thicknesses
in a range from 1.5 to 6 millimeters, in particular 2 millimeters.
Furthermore, a particularly high dimensional stability is able to
be created with tolerances of approximately 0.1 percent.
Furthermore, aluminum die casting components are able to be
adjusted geometrically in terms of stiffness by their hollow
structure with the aid of hollow salt casting cores and are
suitable for vacuum die casting. Such components are therefore able
to be heat treated for ductilization for crash-relevant structural
components. Furthermore, a salt core has the advantage that it is
soluble in water and purely organic, such that it is able to be
cored with no emissions and is completely recyclable.
[0019] In the course of the method according to the invention, it
is furthermore possible to shape the casting core in such a way
that the hollow body or the hollow space is completely closed,
near-net-shaped, reproducible, dimensionally stable and
sufficiently firm such that, for example, a robot can automatically
insert the produced casting core into a correspondingly shaped
aluminum die casting tool. Furthermore, wall thickness thickening
of mounting openings, ridges etc. in the aluminum die casting
component can be achieved in a simple manner by corresponding
design of the casting core.
[0020] The still liquid salt molding material is, for example, a
molten material consisting of a mixture of NaCl with
Na.sub.2CO.sub.3. The proportion of NaCl in the mixture is, for
example, in a range from 30 inclusive to 70 inclusive mass percent.
In particular, the proportion of NaCl in the mixture is 40 mass
percent. In other words, the mass percentage of NaCl in the mixture
is in a range from 30 percent inclusive to 70 percent inclusive. In
particular, the mass percentage of NaCl in the mixture is 70
percent. The radical is Na.sub.2CO.sub.3. This means that the mass
percentage of Na.sub.2CO.sub.3 is in a range from 30 inclusive to
70 inclusive percent, in particular 60 percent.
[0021] A casting core also belongs to the invention, in particular
for metal casting, wherein it is provided according to the
invention that the hollow space is closed on all sides by the
hardened salt molding material. Advantageous embodiments of the
method according to the invention are to be considered as
advantageous embodiments of the casting core according to the
invention and vice versa.
[0022] A further aspect of the invention relates to the use of a
casting core produced according to the method according to the
invention and/or a casting core according to the invention in a die
casting method, in particular in an aluminum die casting
method.
[0023] It has been shown to be particularly advantageous when, in
the context of the method, at least one core mounting protruding
from the hollow body for mounting the casting core in a casting
mold is produced from the salt molding material and by means of the
mold. The hollow body of the casting core forms the actual salt
core contour which is used to produce hollow spaces of casting
components. The core mounting protrudes from this actual salt core
contour, i.e., from the hollow body. This core mounting is used,
for example, in the context of a die casting method, in particular
in the context of an aluminum die casting method, to mount the
casting core on or in a die casting mold. The core mounting
produced in the previously described manner enables a highly
precise and automated positioning of the casting core in a die
casting tool, i.e., in the die casting mold.
[0024] It can thereby be provided that the core mounting is formed
to be solid at least in a partial region. It is thereby conceivable
that the core mounting is formed to be completely solid.
Alternatively, it is possible that the core mounting is hollow. As
a result of the solid or at least partially solid design, the core
mounting is particularly highly robust.
[0025] Simple accessibility into the hollow space, i.e., into the
interior of the casting core, can be enabled by a hollow or
partially solid core mounting, by means of which the casting core
can be removed from the produced casting component in a
particularly simple manner.
[0026] The core mounting can be implemented as a fixed bearing in a
dimensionally stable manner and using casting technology in order
to ensure high dimensional stability of casting components to be
produced by means of the casting core, in particular die casting
components. In other words, it is possible to depict a fixed
bearing by means of the core mounting, by means of which fixed
bearing the casting core is mounted on the casting mold.
[0027] Furthermore, it is possible to implement the core mounting
as a floating bearing in a dimensionally stable manner and using
casting technology in order to be able to balance different thermal
expansions of the casting core and the casting tool. In other
words, it is possible to depict a floating bearing by means of the
core mounting, by means of which floating bearing the casting core
is able to be mounted on the casting mold. The casting mold is
formed, for example, from aluminum. As already depicted, the salt
molding material has a considerably higher thermal expansion than
aluminum. Different thermal expansions of the casting core and the
casting mold can thereby occur when casting or producing a casting
component with the aid of the casting mold and the casting core.
Since the casting core is mounted on the casting mold by means of
at least one floating bearing, these different thermal expansions
can be compensated for as the casting core can be moved to a minor
degree relative to the casting tool.
[0028] Furthermore, it is possible for the core mounting to be used
without mechanical processing for receiving in metal casting tools,
in particular die casting tools and preferably aluminum die casting
tools. In other words, it is possible to produce not only the
hollow body, but also the core mounting, with high dimensional
stability and high surface qualities, such that the core mounting
can be used to directly mount the casting core on a casting mold.
Mechanical processing of the core mounting is not provided and not
required after its production.
[0029] Depending on the loading of the casting core during casting
of the casting component and/or depending on the processing
conditions for the casting core, the core mounting can be designed
to be hollow or solid. Such a core mounting can, for example, be
produced from an overflow feeder during mold filling. In the case
of the casting core, several such core mountings are produced from
respective overflow feeders during mold filling if the mold has
several overflows. Furthermore, it is possible to produce such a
core mounting on the sprue of the mold. Furthermore, it is possible
to produce corresponding core mountings by corresponding molding of
the mold, in particular the cavity.
[0030] Further advantages, features and details of the invention
arise from the following description of preferred exemplary
embodiments as well as with the aid of the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a schematic sectional view through a casting core
according to a first embodiment which has a hollow body formed of a
salt molding material having at least one hollow space which is
delimited by the hardened salt molding material, wherein the hollow
space is closed by the hardened salt molding material on all
sides;
[0032] FIG. 2 is a schematic sectional view through the casting
core according to a second embodiment;
[0033] FIG. 3 is a schematic and perspective top view of the
casting core according to a third embodiment;
[0034] FIG. 4 is a schematic and perspective top view of the
casting core divided into two parts according to FIG. 3;
[0035] FIG. 5 is a schematic and perspective top view of an
aluminum die casting component which is produced with the aid of
the casting core according to a fourth embodiment;
[0036] FIG. 6 is a schematic and perspective front view of the
casting core according to the fourth embodiment; and
[0037] FIG. 7 is a schematic and perspective rear view of the
casting core according to the fourth embodiment.
DETAILED DESCRIPTION OF THE DRAWINGS
[0038] FIG. 1 shows a casting core 10 for metal casting in a
schematic sectional view which can be used as a lost salt core in
an aluminum die casting method. The casting core 10 has a hollow
body 12 which is formed by a hardened salt crust (crust 14). The
salt crust 14 consists of a hardened salt molding material from
which the casting core 10 is produced.
[0039] It can be recognized from FIG. 1 that the casting core 10 or
the hollow body 12 has a hollow space 16 which is formed to be
completely closed, i.e., on all sides. Furthermore, the casting
core 10 has two core mountings 18, 20. In this case, the core
mountings 18, 20 protrude laterally from the hollow body 12 and
serve to mount the casting core 10 in the aluminum die casting tool
on the die casting mold. An optional, moveable slide 22 can also be
recognized from FIG. 1 and FIG. 2 which, for example, is used for
the production of the casting core 10.
[0040] In a method for the production of a casting core 10, the
salt molding material is firstly prepared in the form of a liquid
molten salt. The molten salt, for example, has a temperature from
30 to 80 degrees, in particular from 50 to 80 degrees, above the
solidus temperature. The molten salt consists, for example, of a
mixture of NaCl and Na.sub.2Co.sub.3. The molten salt is preferably
poured into a preferably heated mold, i.e., into a casting mold.
The mold is, for example, formed of steel. The mold is, for
example, formed as a permanent steel mold. The temperature of the
mold is preferably in a range from 250 degrees Celsius inclusive to
350 degrees Celsius inclusive. In particular, the temperature of
the mold is 300 degrees Celsius. Furthermore, it is preferably
provided that the casting core 10 is produced by gravity casting,
low pressure die casting or high pressure die casting.
[0041] The mold has, for example, two mold halves. Further dividers
of this can be implemented as slides, wherein, for example, the
feeders and casting runners provided for mold filling are located
in a parting plane of the casting core 10 formed as a salt casting
part without forming undercuts when molding the casting core
10.
[0042] The mold is filled with the molten salt without air
inclusion, if necessary vacuum assisted and completely including
the feeder and overflows. The mold for the production of the
casting core 10 has a cavity which is filled with the molten salt
via a filling opening leading into the cavity. The thermophysical
properties of the molten salt enable a crust-like, homogeneous
solidification of the molten salt across the whole surface of the
cavity or the mold starting from the mold in the direction of the
hollow space 16, whereby an even, high-strength solidification
layer results in the form of the crust 14. In other words, the
molten salt introduced into the cavity or the mold is cooled, for
example, for 30 to 180 seconds, whereby the firstly still liquid
salt molding material (molten salt) is hardened from the edge,
i.e., from the mold inwards. The firm hollow body 12 is thereby
formed by peripheral shell formation. In the later state arranged
in the aluminum die casting tool, the casting core 10, in
particular the hollow body 12, is cast around with the firstly
liquid casting material such that a hollow space of an aluminum die
casting component is produced.
[0043] The salt mixture has a low thermal conductivity which
reduces heat dissipation from the still liquid molten salt located
in the hollow space 16 into the comparatively colder casting mold
with the increasing thickness of the crust 14, whereby the molten
salt can be kept in liquid form for longer in the interior of the
casting core 10, i.e., in the hollow space 16. The thickness of the
crust 14, i.e., the wall thickness of the hollow body 12, is
determined by the resting time of the molten salt in the casting
mold.
[0044] In order to produce highly loaded core mounting points of
the casting core 10 during the subsequent aluminum die casting
method when producing the casting core 10 in a simple, highly
dimensionally stable, reproducible and cost-effective manner, the
casting system of the mold is used outside the hollow body 12
depicting the actual salt core contour as a core mounting 18 or 20.
The core mountings 18, 20 can thereby be filled to be at least
almost solid, such that they have a particularly high load
capacity, in particular in comparison to the remaining contour of
the casting core 10, since the remaining contour is only formed by
the crust 14.
[0045] The core mounting 18 is, for example, formed on the outlet
feeder of the casting mold and sized in such a way that the first
cut on the casting core 10 is solidified to be completely solid
after crust formation has been completed. The isolation effect of
the crust 14 keeps the molten salt in liquid form in the interior
of the casting core 10 formed by the crust 14. The crust formation
is slowed down logarithmically by the resting time of the molten
salt in the casting core 10.
[0046] It is preferably provided that the cross section of the
feeder on the outlet of the casting mold is sized in such a way
that the peripheral shell formation completely freezes the first
cut and seals the casting core 10 and forms the core mounting
18.
[0047] Furthermore, it is preferably provided that the cross
section of the feeder on the inlet, i.e., on the inlet opening, is
more than double the thickness of the crust 14, such that excess,
still liquid molten salt can be led away from the hollow space 16
via the filling opening, for example can be poured out, wherein
afterwards, the cut surface freezes such that the hollow space 16
is sealed for die casting to form the core mounting 20. Further
core mountings can optionally be produced in the molding direction
of the aluminum die casting part in accordance with requirements
for strength and dimensional stability, such as for example the
core mounting 18. Removing the casting core 10 from the mold and
inserting the casting core 10 into the aluminum die casting tool
takes place, for example, by means of a robot, wherein the robot is
able to grip the casting core 10, for example, on the core
mountings 18, 20. Finally, the casting core 10 is inserted or put
into the aluminum die casting tool.
[0048] In other words, it can be provided that a still liquid first
part of the salt molding material introduced into the cavity of the
mold is led away from the hollow space 16 via the filling opening
and the hollow space 16 is closed at least in the region of the
filling opening by means of a still liquid second part of the salt
molding material introduced into the cavity and located in the
hollow space 16 by hardening this second part. The excess molten
salt can therefore be poured out of the mold either before or, in a
time-controlled manner, after de-mold the salt core by means of a
firstly still remaining opening.
[0049] The still liquid salt molding material introduced into the
cavity is used to close the cavity 16, forming a core mounting at
the same time. This means that no processes following the
production of the casting core 10 are required to close the hollow
space 16. In fact, the hollow space 16 can be closed at least in
the region of the filling opening with the aid of the salt molding
material which has already been introduced into the cavity.
[0050] Alternatively, it is possible that only the quantity of
molten salt required for forming the crust 14 and the core
mountings 18, 20 is filled into the cavity and the filling opening
is designed with a suitably created narrowing which enables the hot
molten salt to be poured in, prevents post feeding by freezing the
molten material at the narrow point and closes the filling opening.
By moving the casting core 10, wherein the casting core 10 can
still be located in the mold or already de-molded from the mold,
the wall thickness can developed, for example, in the region of the
core mountings 18, 20 in addition to the crust formation without
the molten salt being able to escape from the hollow space 16.
[0051] In other words, it is possible to move the casting core 10
around at least one axis, in particular around at least two axes
which run perpendicularly to each other or around three axes which
run perpendicularly to one another and thus three-dimensionally,
while still liquid molten salt is located in the hollow space 16,
whereby the still liquid molten salt located in the hollow space 16
is moved along walls of the casting core 10 delimited by the hollow
space.
[0052] The mechanically fixed crust 14 enables the molding of the
casting core 10 from the casting mold before shrinkage of the salt
molding material by cooling leads to damage to the casting core 10
on regions which are critical for shrinkage such as ridges or wall
strength cracks. With the aid of the residual melt which is still
located in the core, mechanically more highly loaded regions or
regions having lower crust formation inclination such as, for
example, ridge peaks, can be thickened locally by means of
suitable, three-dimensional movements of the casting core 10
outside the casting mold next to the core mountings 18, 20, even in
the subsequent aluminum die casting process, such that the casting
core 10 can thereby be stiffened.
[0053] FIG. 2 shows the casting core 10 according to a second
embodiment. It can be recognized from FIG. 2 that the casting core
10 according to the second embodiment differs from the casting core
10 according to the first embodiment in particular by the design of
the core mountings 18, 20.
[0054] FIG. 3 shows the casting core 10 according to a third
embodiment. It can be recognized from FIG. 3 that the casting core
10 according to the third embodiment has ridges 24 which extend
into the interior of the casting core 10, i.e., into the hollow
space 16. This is particularly recognizable from FIG. 4, in which
the casting core 10 according to the third embodiment is depicted
in two parts. For example, the crust 14 is 8 millimeters thick. The
left core mounting 20 is formed by a closed overflow, whereas the
right core mounting 18 is formed by a closed, partially hollow
sprue.
[0055] FIGS. 5 to 7 show the casting core 10 according to a fourth
embodiment. Furthermore, an aluminum die casting component
generally referred to with 26 is depicted by FIG. 5, the aluminum
die casting component being produced by means of the casting core
10 according to the fourth embodiment.
* * * * *