U.S. patent application number 11/916001 was filed with the patent office on 2008-11-20 for process for producing an object having at least two moving parts.
This patent application is currently assigned to FRAUNHOFER-GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG E.V.. Invention is credited to Frank Ansorge, Kathrin Badstubner, Julian Beck.
Application Number | 20080282527 11/916001 |
Document ID | / |
Family ID | 36991114 |
Filed Date | 2008-11-20 |
United States Patent
Application |
20080282527 |
Kind Code |
A1 |
Beck; Julian ; et
al. |
November 20, 2008 |
Process for Producing an Object Having at Least Two Moving
Parts
Abstract
A process for producing an object having at least two component
parts (3, 4) which can move relative to one another is proposed.
This involves preparing geometrical data of the entire object for a
rapid prototyping process, with a predetermined minimum spacing
between the moving parts being taken into consideration. According
to the predetermined geometrical data, a first material as support
material and a second material as material for the component parts
are applied in layers, the support material filling gaps including
those constituting the minimum spacing between the respective
material for the component parts. Following completion of the
layered construction, the support material is removed.
Inventors: |
Beck; Julian; (Adleberg,
DE) ; Badstubner; Kathrin; (Gauting, DE) ;
Ansorge; Frank; (Munchen, DE) |
Correspondence
Address: |
BARNES & THORNBURG LLP
11 SOUTH MERIDIAN
INDIANAPOLIS
IN
46204
US
|
Assignee: |
FRAUNHOFER-GESELLSCHAFT ZUR
FORDERUNG DER ANGEWANDTEN FORSCHUNG E.V.
|
Family ID: |
36991114 |
Appl. No.: |
11/916001 |
Filed: |
June 2, 2006 |
PCT Filed: |
June 2, 2006 |
PCT NO: |
PCT/EP2006/005599 |
371 Date: |
May 6, 2008 |
Current U.S.
Class: |
29/428 |
Current CPC
Class: |
B29L 2015/003 20130101;
B21D 39/03 20130101; Y10T 29/49826 20150115; B29C 64/40 20170801;
B29C 64/112 20170801 |
Class at
Publication: |
29/428 |
International
Class: |
B21D 39/03 20060101
B21D039/03 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 3, 2005 |
DE |
10 2005 025 664.3 |
May 15, 2006 |
DE |
10 2006 023 369.7 |
Claims
1. A method for manufacturing an object with at least two
components which are movable relative to one another, wherein
geometry data is set up from the whole object for a rapid
prototyping method, wherein a predefined minimal distance between
the moving components is taken into account, wherein a first
material as a support material and a second material as a component
material are deposited in a layered manner according to the
predefined geometry data, wherein the support material fills out
gaps including those with the minimal distance between the
respective component material, and wherein the support material is
removed after the completion of the layered construction.
2. A method according to claim 1, wherein the minimal distance
between the components is determined such that while taking account
of the characteristics of the support material, this may be led
away between the components, on its removal out of the respective
region.
3. A method according to claim 1 wherein at least one molecular
layer of the support material is provided as a minimal distance,
depending in the characteristics of the support material
4. A method according to claim 1 wherein a minimal distance between
the moving parts of larger than 0.1 mm is provided.
5. A method according to claim 1 wherein the support material is
selected such that it may be separated on account of at least one
of its physical and chemical properties which are different with
respect to the component material.
6. A method according to claim 1 wherein the support material has a
lower melting point than the component material, and wherein the
support material is led away by way of increasing the temperature
beyond its melting point.
7. A method according to claim 1 wherein the support material is
wax which has a melting point in the range of 60 to 70.degree..
8. A method according to claim 1 wherein the component material and
the support material are deposited by way of one of printing,
dispensing, and screen printing.
9. A method according to claim 1 wherein the component material and
support material are deposited in a layered manner onto a platform
by way of at least one application apparatus which is controlled
depending on the geometry data, and are subsequently cured.
10. A method according to claim 1 wherein additional geometric
measures are made at at least one of on the components, in the
components, and between the components, which simplify at least one
of a release and flowing away of the support material.
11. A method according to claim 10, wherein the additional
geometric measures are openings, channels or grooves.
12. A method according to claim 11, wherein the opening is
dimensioned such that it has a diameter of at least 1 mm.
13. A method according to claim 1 wherein a structure enclosing a
cavity is selected as one of the at least two movable components,
and a component accommodated in the cavity in a movable manner is
selected as the other component, wherein at least one opening is
provided in the outer structure for the flowing away of the support
material.
14. A method according to claim 1 for manufacturing a gear with at
least two cogs.
15. A gear manufactured according to claim 1 wherein the components
are cogs and shafts.
Description
[0001] The invention relates to a method for manufacturing an
object with at least two components which are movable relative to
one another.
[0002] Rapid prototyping technology is known for manufacturing
prototypes or models or other components, which may also be
designed in a complex manner, and by way of this technology these
objects may be manufactured according to STL (standard
transformation language) data, set up previously in a CAD-program.
One application possibility falling under rapid prototyping
technology is the multi-jet modelling method. This method is a
generative manufacturing method and permits the manufacture of
patterns, prototypes or subjects from shapeless material without
the application of special tools.
[0003] The deposition of the material is carried out with the help
of a print head via a multitude of individual nozzles. In this
manner, high-quality models for e.g. primal shapes which are true
to detail, may be prepared in a cost-effective manner and within
the shortest of times for subsequent processes, such as vacuum
casting for example.
[0004] Thereby, the model is constructed on a component platform.
Basically, the model is manufactured in a layered manner on the
basis of the contour data computed for each construction plane from
the STL data set. Firstly, a special support geometry is plotted
for the unambiguous setting of the construction layers to be
manufactured on the construction platform. The component material
is subsequently deposited in the width of the print head, wherein
the print head is guided by way of a computer-controlled travel
mechanism. Thereafter, the construction platform is displaced by a
print head width, when the model is larger than the width of the
print head. The support material with regard to the layered
construction is set such that overhanging structures of the
component material which are provided in the layers deposited
later, are supported by the layers of the support material which
lie thereunder. After construction of the whole layer, the
construction platform is lowered by a layer thickness, and the
print heads follow this. The component material is thermoplastic
and is melted and deposited through the nozzles of the print head
in the form of droplets, and subsequently cured by UV-light. The
additionally deposited support structure is melted away in a
furnace after the printing.
[0005] As already stated, a wax-like thermoplastic is applied as a
component material, for example an acrylic photopolymer, which
holds together wax constituents in an acrylate base structure. The
wax constituents have a melting point of approx. 65.degree. C., and
in combination with the acrylate, the models may however be
subjected to a temperature of approx. 80.degree. C. The material
for the support geometry is likewise a wax, and is melted away in
the heat furnace at approx. 70.degree. C.
[0006] The advantages of the described method, when compared to
other rapid prototyping systems, particularly lie in the high
resolution of the models. Layer thicknesses of 800 DPI (corresponds
to approx. 32 .mu.m) may be achieved in the z-direction, and layers
with a resolution of 656 DPI may be printed in the x- and
y-direction. Until now, the method has been used to produce
components, wherein each component was manufactured individually
according to the above method and then assembled for multi-part
objects. With a gear, e.g. each cog had to be printed, melted-off
and placed on the shaft individually. Since the gear was assembled
together at a later point in time, it was also necessary to use
suitable geometries for this. E.g. with the construction of a shaft
with the CAD-program, one had to provide open geometries in order
to subsequently be able to assembled the cogs.
[0007] It is therefore the object of the invention to provide an
object with several moving parts according to the rapid prototyping
method, with which the object as a whole may be manufactured with
less effort with regard to time, and with simplified
geometries.
[0008] According to the invention, this object is achieved by the
features of the main claim.
[0009] It is possible to manufacture the object with all parts in a
direct manner, by way of the fact that geometry data is set up from
the whole object with its moving, and, as the case may be,
stationary components, for a rapid prototyping method, whereon a
predefined minimal distance between the moving parts is taken into
account, and that, in a layered manner according to the defined
geometry data, a first material is deposited as a support material,
and a second material as a component material, wherein the support
material fills gaps including those with the minimal distance and
that the support material is removed after completion of the
layered construction. Thus, the additional assembly and the time
effort which this entails are done away with. Moreover, one does
not need to take any geometry into account or to provide this,
which would permit the disassembly or assembly of the object at a
later point in time. A greater stability is simultaneously
achieved.
[0010] Advantageous further formations and improvements are
possible by way of the features provided in the dependent
claims.
[0011] The minimal distance between the moving components is
dependent on the characteristics of the support material, on the
size of the moving parts and/or on the possibilities of deposition.
Whilst taking into account the characteristics of the support
material, it is envisaged for this to be able to be led away with
its removal from the region between the components. The minimal
distance is a molecular layer, given a relatively low viscosity and
a high resolution on depositing the support material.
Advantageously, a minimal distance of greater than 0.1 mm is
provided, depending on the characteristics of the support material,
in particular with support wax, and on the size of the components
movable to one another.
[0012] The support material is separated on account of its physical
and/or chemical characteristics, which are different to the
component material.
[0013] For structures which may be moved to one another, and which
likewise are manufactured by way of a component material in the
density range of approx. 1.01 g/cm.sup.3 (at 25.degree. C.) and in
the viscosity range of 12 to 14 mPas (at 80.degree. C.), it is
likewise necessary on account of the resolution, to maintain a
distance of at least 100 to 130 .mu.m between the individual
components, in order to ensure the mobility. For this, the surfaces
lying parallel to one another and which are to be movable to one
another, should not be greater than 30 mm.sup.2. If this is indeed
the case, then the viscosity of the support material is an
additional determining factor, since this is prevented from flowing
away by the acting capillary forces. For this reason, a distance of
two surfaces lying parallel opposite one another of at least 0.3 mm
is necessary for a support material of the viscosity range of about
10 to 12 mPas (at 80.degree. C.) and of the density range of
approx. 0.91 g/cm.sup.3.
[0014] If material must flow away through a hole, i.e. from the
inside of a cavity to the outside, then the diameter of this
opening on account of the viscosity (region: viscosity region of
about 10 to 12 mPas at 80.degree. C.) of the support material must
be at least 1 mm.
[0015] It is particularly advantageous for the support material to
be selected such that it has a lower melting point that the
component material, by which means the support material may be led
away in a simple manner by way of increasing the temperature beyond
the melting point. Other support materials are also conceivable,
which may be separated from the component material by way of
etching, plasma treatments, different solubilities in reagents, or
subjection to a radiation. The component material layers and
support material layers may be deposited in a different manner,
e.g. by way of printing, by way of dispersing, by way of screen
printing and likewise. Advantageously, the different layers of
component material and support material are deposited through a
printing head via nozzles, which is controlled depending on the
geometry data. The method for the construction of the object by way
of printing head thus permits a simple manufacture.
[0016] In an advantageous embodiment example, additional
geometrical measures are taken on, in or between the components,
such as channels, grooves or holes, which simplify a release and/or
flowing-away of the support material.
[0017] For example, it is now possible to manufacture an object
with a component, which has a structure enclosing a cavity, e.g. a
ball, wherein a further component, e.g. a further ball is received
in this structure, e.g. the first mentioned ball in a moving
manner. With a manufacturing process of two different balls which
takes its course in a separate manner, it is no longer possible to
integrate these afterwards. An assembly is superfluous with the
help of the method according to the invention. It is merely
necessary to provide one or more smaller holes in the outer ball,
in order with this, to permit the draining of the support material,
e.g. of the support wax. Here too, the diameter is dependent on the
characteristics of the support material, and with support wax a
diameter of 1 mm is already adequate for these holes.
[0018] It is now possible to manufacture more complex objects which
have moving parts, with a print procedure. By way of this, it is
further possible to manufacture components which may be applied
beyond the stage of an illustrational pattern, also as functional
prototypes. For example, these prototypes may be used directly in
mechanical, electronic or mechatronic assemblies of a machine. This
has hitherto only been possible to a limited extent, since the
characteristics of the component manufactured of wax only permit
this to be used in a very limited field of application. Future or
other materials may expand this restricted field of application.
These may for example be eclectically and/or thermally conductive
plastics (e.g. by way of metallic fillers) or other types of
plastics or metals, which for example have an improved modulus of
elasticity, and improved bending modulus, an increased bending
strength, a lower extension at break, a greater tensile strength
and/or an increased application temperature.
[0019] An object with moving parts is represented in the drawing
and its method for manufacturing is explained in more detail in the
following description. There are shown in
[0020] FIG. 1: a plan view of a gear,
[0021] FIG. 2: a perspective view in a taken-apart condition of the
gear, according to FIG. 1,
[0022] FIG. 3: a perspective view of the gear according to FIG. 1
and
[0023] FIG. 4: a view of the gear according to FIG. 1 seen from
below.
[0024] The gear which is to be manufactured with the method
according to the invention, and is represented in the FIGS. 1, 3
and 4, comprises a membered-like base plate 1, on which stationary
shafts 2 for cogs 3 connected to it are provided.
[0025] The cogs 3 and shafts 2 are shown separately from one
another in FIG. 2 for a better understanding, although they are
manufactured in the assembled condition. Furthermore, a smaller
drive cog 4 is provided, which comprises a shaft stub 5 which is
firmly connected to it, which engages through a recess 6 in the
base plate 1 and which may be connected to an electric motor which
is not represented.
[0026] A distance or play is provided between the cogs 3, 4 and the
shafts 2, as well as between the shaft stub 5 and the recess 6.
[0027] The cogs 3 are held on the shafts 2 by way of a bar 7,
whereas the drive cog 4 is fixed in the recess by way of a flange
8.
[0028] A distance between the cog 3 and the base plate 1 is
specified at 9, with is to be kept to during manufacture, so that
the support wax which is used with this, may flow away. Such a
distance is always provided if two moving parts lie opposite one
another, as is the case with the distance mentioned above, between
the cogs 3 and shafts or the cog 4 with the shaft stub 5 and the
base plate and recess 6, or flange 8 and the base plate 1.
Additionally, holes 10 as geometries supporting the flowing-away of
the support wax are incorporated in the base plate 1 around the
recess 6, as well as also in the drive cog 4.
[0029] The cogs 3 have a diameter of approx. 3 cm and the drive cog
4 a diameter of approx. 1 cm in the embodiment example. In such a
case, the distance 9 and the respective distances mentioned above
are to be dimensioned to at least 0.1 to 0.13 mm. This distance
increases to at least 0.3 mm if the surfaces lying parallel
opposite to one another are larger than 30 mm.sup.2, i.e. if
support wax of an area of greater than 30 mm.sup.2 must be melted
away. The holes 10 must have a diameter of at least 1 mm, in order
to permit the support wax to flow away.
[0030] The components of the gear have firstly been drawn
individually in a design program, and subsequently assembled with
this program into an assembly. On assembly with the design program,
care was taken that the mentioned minimal distances of the parts to
one another were adhered to, so that the support wax may correctly
flow away during the melting procedure in the heating furnace. The
CAD-drawing is a digital plane picture of the later gear which is
represented in the FIGS. 1 to 4, and is present as an STL-file.
[0031] As has been specified above, a base structure of support
material, such as support wax, is deposited on a construction
platform, whereupon the various layers are deposited with a printer
to which the STL-file is supplied, in the different materials, the
component material and the support material. The construction
platform and the printer thereby may be displaced relative to one
another in a three-dimensional manner.
[0032] Gaps or distances as previously computed, are provided
between the respective component regions of each layer, and these
are filled out with the support material, wherein the different
materials are deposited in a geometrically correct manner with the
printing procedure of the layer. After the finished construction in
the 3D-printer, which encompasses the gear with the support
material lying therebetween, this support material, as the case may
be, is cured, and subsequently melted away in an furnace. A gear
with moving cogs remains after the melting away.
* * * * *