U.S. patent application number 11/726448 was filed with the patent office on 2007-07-19 for tool and method for its manufacture.
Invention is credited to Bengt Berg, Christer Svensson.
Application Number | 20070163742 11/726448 |
Document ID | / |
Family ID | 20285960 |
Filed Date | 2007-07-19 |
United States Patent
Application |
20070163742 |
Kind Code |
A1 |
Berg; Bengt ; et
al. |
July 19, 2007 |
Tool and method for its manufacture
Abstract
A method is disclosed for manufacturing a tool or a part thereof
for carrying out operations such as pressing, cutting, hemming and
the like, and in which the tool is given different material
properties in different parts of the tool, wherein the tool is cast
to one united piece, the casting material with at least two
different material properties being supplied, one to each of the
different parts of the tool, and at least one of the casting
materials being supplied in liquid form.
Inventors: |
Berg; Bengt; (Olofstrom,
SE) ; Svensson; Christer; (Jamshog, SE) |
Correspondence
Address: |
BACHMAN & LAPOINTE, P.C.
900 CHAPEL STREET
SUITE 1201
NEW HAVEN
CT
06510
US
|
Family ID: |
20285960 |
Appl. No.: |
11/726448 |
Filed: |
March 21, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10495396 |
Jun 11, 2004 |
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PCT/SE02/02064 |
Nov 12, 2002 |
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11726448 |
Mar 21, 2007 |
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Current U.S.
Class: |
164/96 ; 164/93;
164/95 |
Current CPC
Class: |
B21D 37/01 20130101;
Y10T 83/9309 20150401; B21D 37/20 20130101; B21D 37/205 20130101;
B22D 19/06 20130101; B22D 19/16 20130101 |
Class at
Publication: |
164/096 ;
164/093; 164/095 |
International
Class: |
B22D 19/16 20060101
B22D019/16 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 13, 2001 |
SE |
0103769-6 |
Claims
1-4. (canceled)
5. A method of manufacturing a tool or a part thereof for carrying
out operations such as pressing, cutting, hemming and the like, and
in which the tool is given different material properties in
different parts of the tool, characterised in that the tool is cast
to one united piece, the casting material with at least two
different material properties being supplied, one to each of the
different parts of the tool, and at least one of the casting
materials being supplied in liquid form.
6. The method as claimed in claim 5, characterised in that, in the
casting operation of the tool, casting materials of different
compositions are kept separate and discrete from one another.
7. The method as claimed in claim 5, characterised in that, in the
casting of the tool, casting materials of different compositions
are intermingled in a zone between parts of the tool, where the
material composition differs.
8. The method as claimed in claim 5, characterised in that at least
one of the tool parts is at treated.
9. The method as claimed in claim 5, characterised in that at least
one of the tool parts is provided with a surface coating.
Description
TECHNICAL FIELD
[0001] The present invention relates to a tool or a part thereof
for carrying out operations such as pressing, cutting, hemming and
the like and includes at least a first and a second tool part with
different functions in the tool, for example a tool body amid an
functional part disposed thereon in order, alone or together with
some other additional functional part, or additional tool, to carry
out the operation, the first-and the second parts possessing
different material properties.
[0002] The present invention also relates to a method for
manufacturing a tool or a part thereof, for carrying out operations
such as pressing, cutting, hemming and the like, and entails that
the tool is given different material properties in different parts
of the tool.
BACKGROUND ART
[0003] In the manufacture of a tool for the above-outlined purpose,
it has previously been the practice to separately manufacture a
tool body which subsequently, ill the example of a cutting tool, is
provided with one or more cutters. The manufacture of the tool body
may be put into effect by casting or by welding on the basis of
suitably dimensioned sheet material of appropriately adapted
material composition
[0004] In the case of a cast tool body, this often requires heat
treatment after the casting, whereafter machining is put into
effect in order to obtain the requisite seats, guide pins and bolt
holes for securing the cutters, but also in order to make possible
securing of the tool body in a machine.
[0005] Correspondingly, in the alternative of welding of the tool
body, extensive machining is required in order to be able to secure
one or more cutters on the tool body and in the correct position,
and in order to be able to secure the tool in a machine.
[0006] In the manufacture of the functional part or parts, in the
above-disclosed example the cutters, which are intended for
carrying out the. operations for which the tool has been designed,
the point of departure has previously often been rod or bar
material in which event the functional parts, in this example the
cutters, are machined to the correct configuration, provided with
apertures and anchorage bolts, guide pins and the like. This is
often followed by a heat treatment, whereafter further machining
such as, for example, grinding, is put into effect
[0007] To manufacture a tool in the above-outlined maimer is
extremely time-consuning and such manufacture is, as a result,
often determinative of the time consumption required in the new
manufacture of different products.
[0008] It is also previously known in the art, in the manufacture
of tools by welding, flash welding and similar methods, to apply a
material of a different composition, for example to a tool body so
that a functional part is formed thereon. By such means, a tool
will be obtained which consists of a single material piece, but in
which the material composition in different parts thereof
differs.
[0009] Also in this alternative, extensive machining is required,
for example in the form of joint preparation in welding and
after-treatment of a weld before additional welding material can be
applied When the material application is completed, further
machining is required, possibly also heat treatment and subsequent
grinding before the tool is ready to be made operational.
[0010] When a tool has become obsolescent, for example because the
part which is produced in the tool has itself become obsolete, or
because the tool has quite simply become worn out the entire tool
is scrapped, even though the tool body could very well be re-used.
This naturally entails a waste of material, time and money.
Problem Structure
[0011] The present invention has for its object to obviate the
drawbacks inherent in the prior art technology. Principally, the
present invention has for its object to shorten the production time
for a tool, but also to minimise the need of machining in the
manufacture of the tool and to male possible the retro-construction
of an obsolescent tool.
[0012] Concerning the tool, the present invention has for its
object to design the tool or a part thereof such that different
parts of the tool display different material compositions adapted
so as to impart to the different parts their intended material
properties.
[0013] Concerning the method, the present invention has for its
object to propose a method for the manufacture of a tool or a part
thereof in which different parts of the tool may be given different
material compositions and, consequently, different material
properties.
Solution
[0014] The objects forming the basis of the present invention will
be attained concerning the tool is this is characterised in that
the first and the second tool parts are cast in one united piece
and that they possess different material compositions.
[0015] The objects forming the basis of the present invention will
be attained concerning the method if this is characterised in that
the tool is cast in one united piece, the casting material of at
least two different material compositions being supplied to the
different parts of the tool and at least the one casting material
being supplied in liquid form.
BRIEF DESCRIPTION OF TEE ACCOMPANYING DRAWINGS
[0016] The present invention will now be described in greater
detail hereinbelow, with reference to the accompanying Drawings. In
the accompanying Drawings:
[0017] FIG. 1 is a cross section through a part of a tool, in this
case a cutting tool;
[0018] FIG. 2 is a partial cross section, on a larger scale,
through a part marked by means of the arrow A of the tool of FIG.
1; and
[0019] FIG. 3 is a cross section through a mould for manufacturing
a tool according to the present invention,
DESCRIPTION OF PREFERRED EMBODIMENT
[0020] In FIG. 1, reference numeral 1 relates to a machine bed or
foundation on which the tool 2 is secured by means of a bolt union
3.
[0021] The tool illustrated ill FIG. 1 by way of example is a
cutting tool which is in two parts and consists therefore of two
tool parts, a lower tool part 2 and an upper tool part 4. The tool
parts 2 and 4 are, however, in this context considered as separate
tools.
[0022] A tool may be thought of as being composed of a plurality of
different components, for example a tool body and a functional part
d the illustrated example, the functional part would consist of a
cutter which is intended to carrying out the processing operation
together with a corresponding functional part on the upper tool
4.
[0023] In FIG. 1, the tool 2 includes a tool body 5 which has a
lower mounting plate 6 for securing the tool on the tool table or
bed 1. Further, the tool body 5 includes an upper part 7 which, in
the illustrated embodiment, has rigidification ribs 17. The upper
part 7 is connected to the anchorage plate 6 by the intermediary of
a wall portion 8.
[0024] The tool 2 illustrated in FIG. 1 has a functional part 9
which is intended to realise the cutting operation proper and which
is supported by and is of one piece manufacture with the tool body
5. The functional part 9 has an edge 10, a flank or rake 11 and a
surface 12 on which the workpiece is supported during a cutting
operation.
[0025] Correspondingly, the upper tool 4 has a functional part 13
with an edge 14, a flank or rake 15 and a surface 16 for abutment
against the workpiece.
[0026] When the tool is in operation, the workpiece rests on the
tool 2, in particular on its upwardly facing surface 12, and
extends more or less outside the edge 10 in a direction to the
right in FIG. 1. in one working stroke, the upper,tool 4 moves
according to the arrow B so far down that the edge 14 passes down
to or slightly past the edge 10. Thus, during the working
operation, it is both of the functional parts 9 and 13 that realise
the working operation, in this case the cutting operation.
[0027] It will readily be perceived that the two edges 10 and 14,
as well a surrounding parts of the tools, must display superior
mechanical strength, both toughness and hardness, as well as in
addition an ability to produce relatively sharp edges. This is a
requirement which the tool body 5 by no means needs to satisfy but,
as regards the tool body proper, it is properties such as, for
example, vibration damping and slight outward flexing which are
more important than those properties that are required for carrying
out the wL g operation itself For this reason, both of the
functional parts 9 and 13 possess totally different material
properties than does the tool body 5.
[0028] In actual fact, different material properties could be
achieved in a tool which, in its entirety, consists of one and the
same material, but in which different parts of the tool are treated
in different ways, for example by heat treatment. However, this
implies a limitation in those differences in material properties
that may be attained and, on the other hand, unnecessary costs
since probably one material which is appropriate for one functional
part may be considered as overqualified in a tool body.
[0029] According to the present invention, those parts of a tool
which, because of different functional requirements, possess
different material properties, also have a different composition of
the material lying behind the different material properties.
[0030] In the manufacture of a tool according to the present
invention, this is cast from at least two different casting
materials of different material compositions into one united piece.
The term casting is taken to signify that a liquid carrying
material is supplied into a mould where the cast material is
allowed or caused to harden into a casting whose form is defined by
the form of the mould cavity which is enclosed in the mould The
casting operation may be put into effect such that a clear and
sharp interface between the different casting materials is
achieved, or alternatively the casting operation may be put into
effect so that a certain intermingling of the two casting materials
takes place in an interface zone.
[0031] In the casting operation so that a sharply defined interface
occurs, the first cast part of the tool is allowed to harden so far
that no intermingling of the casting materials occurs.
Alternatively, use may be made of a tool part which is cast in a
separate process or which has been recovered and recycled from at
old, obsolete tool and which, in the heated state (600-750.degree.
C.) is inserted in a mould where an additional tool part is cast
or
[0032] In the casting so that an interface zone is formed between
the tool parts, the hardening and cooling of the first cast tool
part is allowed to continued only so far that a limited
intermingling of the cast materials can take place or that a
certain remelt of the already cast tool part can take place. The
positive cooling or rest cooling of the cast material which was
cast first may also be put into effect in a directed fashion, so
that a hardening zone migrates through the casting and finally
arrives at that side of the tool part where the additional
casting-on is to take place.
[0033] In casting according to the present invention, sand foundry
casting is often employed where the mould cavity at the beginning
of the casting operation is filled by a template or model which is
broken down and vaporised on the supply of the hot and liquid
casting material. The model can, for example, be produced from
expanded polystyrene. The material from the model floats up on the
casting material and is accumulated uppermost on it where it may
cause local deterioration in quality in the casting material. For
this reason, the mould is oriented in such a manner and the tool
parts are cast in such a sequence that the local deterioration in
quality will have as slight consequences as possible. In
particular, it is to be ensured that the local deterioration in
quality of the casting material is located at a distance from the
functional surface of the functional parts, i.e. that surface on
the tool which carries out the functional proper of the tool.
[0034] FIG. 2, which shows a partial magnification of the
functional part 9 and thereby the area A of the tool 2 in the
proximity of the edge 10, shows a dotted area 18 and a dashed area
19 where the two areas 18 and 19 display different material
compositions. In FIG. 2, the interface between the two areas 18 and
19 is clearly marked and can, in a practical version, amount to an
extremely thin interface layer or strata between the two areas.
[0035] However, if a more continuous transition between the areas
18 and 19 is desirable, it is possible in the manufacture of the
tool, to intermingle, in an interface zone between the areas 18 and
19, both of the different materials from the areas 18 and 19.
[0036] FIG. 2 further shows a third area 20 which, in the Drawing,
is marked by ringlets. This third area 20 is thereby intended to
have yet another, third material composition and consequentially
different material properties than those possessed by the
functional parts in the areas 18 and 19. For example, the area 20
marked by the ringlets may consist of a relatively cheap material
which is employed for the greater part of the tool body 5.
[0037] In order to ensure that at least the functional part 9
possesses accurately Controllable material properties, use is made
of a casting material in granulate form and of high purity, as well
as an analysis of small tolerances.
[0038] Those parts 9 and 13 of the tool which carry out the working
operation proper, the functional parts, should possibly undergo,
after the casting operation, a minor machining operation to the
intended tolerances and grinding finish Possibly, these parts may
also be heat treated so that the material properties will be those
intended in the end product. Correspondingly, the functional parts
may be provided with a coating of a material comprising yet a
further different composition.
[0039] FIG. 3 shows a vertical cross section through one example of
a mould which may be employed for the production of a tool
according to the present invention. In the Figure, the tool is
shown as ready-cast in the inverted state and it will be apparent
that the tool has an anchorage plate 6, side walls 8 and an upper
region 7. The previously named parts of the tool may be considered
as a tool body which, for example, may be cast in a material of
relatively low quality,
[0040] In its upper region (that turned to ice downwards in the
Figure), the tool has a functional part 9 which is cast from a
material possessing different composition than the tool body and
which has those properties that are needed in the functional
surface 21 of the tool, i.e. that surface which produces the
forming function of the tool.
[0041] It will further be apparent from the Drawing that there is
an interface zone between the fictional part 9 and the tool body
where,the two cast materials meet one another.
[0042] Before the casting of the tool according to FIG. 3, it may
be assumed that the mould cavity of the mould was filled by a model
or template consisting of expanded polystyrene. In the casting, the
material for forming the functional part 9 is first cast from the
ladle 22 down into the gate 23 of the mould. In this instance, the
hot and molten casting material will vaporise and break down Cat
part of the model which is in contact with the casting material.
This material thus finds no difficulty in penetrating through the
model and in arriving at the lower surface of the mould where the
functional surface 21. of the tool is formed. The degradation
products from the model float upwards on the casting material and,
as a result, may possibly bring about a local deterioration in the
quality therein.
[0043] When the functional part 9 has been cast and allowed to
harden wholly or partly, depending on the desired interface zone
between the functional part and the tool body, the material for
forming the tool body is supplied via the gate 23. It this
instance, remaining parts of the model will be broken down and
vaporised as well as float upwards in the mould. The local
deterioration of the material quality which the material of the
model per se may possibly cause will, as a result, arrive uppermost
in the mould, i.e. in the anchorage plate 6 of the tool where any
possible deterioration in quality will have as slight consequences
as possible.
[0044] The present invention also embodies the possibility that an
existing but obsolescent tool may at least partly be recycled and
reused. In this instance, the existing tool is cleaned, whereafter
its functional part is removed, e.g. by being milled or ground off.
A fully usable tool body will remain, which is to be provided with
a new functional part.
[0045] The functional part may be realised in that a block of
expanded polystyrene is secured to the processed tool body,
whereafter a template or model for the functional part is formed by
the blocks Thereafter, a mould is produced which on the one hand
encloses a mould cavity for the new functional part and on the
other hand at least a part of the old tool body, the tool body
being located uppermost and the mould cavity lowermost The mould
has a gate whose lower end discharges in the interice zone between
the tool body and the mould cavity. Possibly, the model or template
may be left in place in the mould cavity.
[0046] On casting of the new functional part, if the model is still
in place in the mould cavity, it will be vaporised and the residue
will float up on the casting material. This implies that any
possibly negative effect on the casting material which may be
caused by the residual products from the model will be located a
distance from the working surface of the functional part and, more
precisely, m an interface zone between the old tool body and the
new functional part
[0047] On casting a new functional part on an old tool body, it is
crucial that the tool body be heated to a temperature suitable for
casting on, often of the order of magnitude of 650-700.degree. C.,
As a result, the mould is provided with a heating device.
Alternatively, the tool body may be provided with a heating device
or be pre-heated beforehand.
[0048] Once the casting of the new functional part is finished, the
tool is removed from the mould and the functional part cleaned and
sand blasted Thereafter, possible later heat treatment and
fine-adjustment of the working surface way be put into effect.
* * * * *