U.S. patent application number 14/467225 was filed with the patent office on 2015-02-26 for apparatus and method for manufacturing three-dimensional objects.
The applicant listed for this patent is FIT FRUTH INNOVATIVE TECHNOLOGIEN GMBH. Invention is credited to CARL FRUTH.
Application Number | 20150054200 14/467225 |
Document ID | / |
Family ID | 51357703 |
Filed Date | 2015-02-26 |
United States Patent
Application |
20150054200 |
Kind Code |
A1 |
FRUTH; CARL |
February 26, 2015 |
APPARATUS AND METHOD FOR MANUFACTURING THREE-DIMENSIONAL
OBJECTS
Abstract
An apparatus and a method manufacture three-dimensional objects
by selective solidification of a build material applied in layers.
In order to improve the manufacturing process and in particular to
optimize heat input, a heating element is provided that has at
least two functional openings. One of the at least two functional
openings serves as a material pass-through and another of the at
least two functional openings serving simultaneously as a radiation
pass-through.
Inventors: |
FRUTH; CARL; (PARSBERG,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FIT FRUTH INNOVATIVE TECHNOLOGIEN GMBH |
PARSBERG |
|
DE |
|
|
Family ID: |
51357703 |
Appl. No.: |
14/467225 |
Filed: |
August 25, 2014 |
Current U.S.
Class: |
264/405 ;
425/150 |
Current CPC
Class: |
B29C 64/30 20170801;
B22F 2003/1056 20130101; B29C 64/393 20170801; B22F 3/1055
20130101; B29K 2105/251 20130101; B28B 1/001 20130101; B22F
2003/1057 20130101; B29C 64/364 20170801; B29C 64/295 20170801;
B33Y 10/00 20141201; B33Y 50/02 20141201; B29C 64/153 20170801;
B29C 64/40 20170801; Y02P 10/295 20151101; B28B 17/0081 20130101;
Y02P 10/25 20151101; B33Y 30/00 20141201 |
Class at
Publication: |
264/405 ;
425/150 |
International
Class: |
B29C 67/00 20060101
B29C067/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 23, 2013 |
DE |
102013109162.8 |
Claims
1. An apparatus for manufacturing three-dimensional objects by
selective solidification of a build material applied in layers, the
apparatus comprising: a build platform, disposed in an X-Y plane,
on which at least one three-dimensional object is generated in
layers; a heating element, at least partly overlapping said build
platform, for inputting thermal energy into the build material,
said heating element having at least two simultaneously usable
functional openings formed therein, wherein one of said at least
two functional openings being a material pass-through and another
of said at least two functional openings being a radiation
pass-through; and a drive device for generating a relative motion
in an X-Y direction between said build platform and said heating
element.
2. The apparatus according to claim 1, wherein said heating element
constantly at least partly overlaps said build platform.
3. The apparatus according to claim 1, wherein said heating element
and said build platform can be caused to overlap one another
completely.
4. The apparatus according to claim 1, wherein said heating element
is of a substantially plate-shaped configuration.
5. The apparatus according to claim 1, wherein said heating element
is disposed above said build platform and either is spaced away
from a topmost build layer or touches the topmost build layer.
6. The apparatus according to claim 1, further comprising a process
chamber, said build platform is disposed inside said process
chamber that is closed in an operating state, and said heating
element serving as a demarcating wall of said process chamber.
7. The apparatus according to claim 1, wherein said heating element
contains regions capable of different temperature control.
8. The apparatus according to claim 1, wherein a shape of said
functional openings is modifiable.
9. The apparatus according to claim 1, further comprising an
additional heat source embodied to furnish the thermal energy,
wherein one of said at least two functional openings is embodied
simultaneously or exclusively as a heating opening for additional
input of the thermal energy.
10. A method for manufacturing three-dimensional objects by
selective solidification of a build material applied in layers,
which comprises the steps of: generating at least one
three-dimensional object, in layers, on a build platform disposed
in an X-Y plane; inputting thermal energy into the build material
via a heating element at least partly overlapping the build
platform, wherein the heating element, using at least two
functional openings, allowing the build material and radiation
energy to pass through simultaneously; and generating, via a drive
device, a relative motion in an X and/or Y direction between the
build platform and the heating element.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority, under 35 U.S.C.
.sctn.119, of German application DE 10 2013 109 162.8, filed Aug.
23, 2013; the prior application is herewith incorporated by
reference in its entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The invention relates to an apparatus and a method for
manufacturing three-dimensional objects by selective solidification
of a build material applied in layers.
[0003] A large number of apparatuses and methods for manufacturing
three-dimensional objects by selective solidification of a build
material applied in layers are known from the existing art. Laser
sintering or selective mask sintering, for example, may be recited
here. Systems with which a layer manufacturing method of this kind
can be carried out are also referred to as "rapid prototyping"
systems. These layer manufacturing methods serve to manufacture
components built up in layers from a solidifiable material such as
resin, plastic, metal, or ceramic, and are used, for example, to
produce engineering prototypes. Using an additive production
method, three-dimensional objects can be manufactured directly from
CAD data.
[0004] In a layer manufacturing method of this kind, the objects
are built up in layers, i.e. layers of a build material are applied
successively over one another. Before application of the respective
next layers, the locations in the respective layers which
correspond to the object to be manufactured are selectively
solidified. Solidification is accomplished, for example, by local
heating of a usually powdered layering of raw material using a
radiation source. An exactly defined object structure of any kind
can be generated by controlled introduction of radiation in a
suitable fashion into the desired regions. The layer thickness is
also adjustable. A method of this kind is usable in particular for
the manufacture of three-dimensional bodies by successively
generating multiple thin, individually configured layers.
[0005] The build material to be solidified is typically preheated
to a temperature that is below the processing temperature. The
processing temperature is then attained with the aid of an
additional energy input.
[0006] In a laser sintering process, for example, a plastic
material is preheated to a temperature below the sintering
temperature. The energy introduced by the laser then contributes
only the differential quantity of heat for fusing the powder
particles.
[0007] Preheating is accomplished in many cases by heating the
build platform. With this heating "from below," however, the
preheating heat flow decreases as the component height increases,
due to losses and the increasing volume of the powder charge.
[0008] Other methods also result in an undesired irregular
temperature distribution in the build material. This also applies
in particular to those methods in which preheating is accomplished
by heat delivery "from above." Here devices that can be
intermittently heated are placed above the build layer. Complex
systems for controlling the heat curve, and other laborious
actions, are used in an attempt to achieve a uniform temperature
distribution in the build material to be preheated.
SUMMARY OF THE INVENTION
[0009] An object of the present invention is to improve the
manufacturing process, in particular to optimize heat input.
[0010] The invention proposes no longer pursuing the cycle-timed
manufacturing procedure known from the existing art, in which,
within one clock cycle, after an application of a material first a
preheating action and then a selective solidification action occur
before another material application is performed in a subsequent
new clock cycle. The invention instead proposes a continuous
manufacturing process in which application of the build material,
preheating, and selective solidification occur simultaneously by
local heating of the build material, specifically at different
sites on the same objects to be manufactured or also on different
objects simultaneously if multiple objects are being manufactured
on the build platform.
[0011] The apparatus according to the present invention encompasses
a build platform, arranged in an X-Y plane, on which at least one
three-dimensional object is generated in layers. A heating element
is provided which at least partly overlaps the build platform, for
inputting thermal energy into the build material. The apparatus
further has a drive device for generating a relative motion in an
X-Y direction between the build platform and the heating element.
The heating element contains at least two simultaneously usable
functional openings, one of the at least two functional openings
being embodied as a material pass-through and another of the at
least two functional openings being embodied as a radiation
pass-through.
[0012] The method according to the present invention
correspondingly encompasses the steps of: generating the at least
one three-dimensional object, in layers, on a build platform
arranged in an X-Y plane; inputting thermal energy into the build
material with the aid of a heating element at least partly
overlapping the build platform; generating a relative motion in an
X and/or Y direction between the build platform and the heating
element by means of a drive device; and simultaneously causing the
build material and the radiation energy to pass through the heating
element using at least two functional openings.
[0013] A fundamental idea of the invention is the use of a heating
element that serves to preheat the build material and is notable
for functional openings that serve as a material pass-through and
radiation pass-through, therefore as a coating opening for the
application of the build material and as an exposure opening for
local heating of the build material. When a heating element of this
kind is moved in suitable fashion relative to the build platform,
the application of the build material, the preheating, and the
selective solidification can occur simultaneously, i.e.
non-cycle-timed, uninterrupted manufacture of the at least one
object. In other words, the object or objects is built up
continuously, the build rate being determined by the relative
motion between the build platform and heating element. The
geometric arrangement of the object regions located in the various
manufacturing process phases, in particular the spacing of the
object regions from one another, is determined by the arrangement
of the functional openings in the heating element, in particular by
the spacing of the functional openings from one another.
[0014] For example, in a first object region the build material in
the form of a freshly applied powder charge is being preheated by
the heating element, while in a second object region arranged
behind the first object region in the motion direction, a layer n
currently being solidified with the aid of radiation energy
penetrating through an exposure opening. At the same time, in a
third object region that is located behind the second object region
in the motion direction, post-heating of the build layer n, just
previously solidified there, is being performed by the heating
element, while in a fourth object region located behind the third
object region, further build material for a subsequent layer n+1,
introduced through a coating opening, is being applied onto the
layer n that is already present. The object regions can be regions
of one object or regions of different objects if multiple objects
are arranged on the build platform.
[0015] Heat delivery for preheating is accomplished "from above,"
so that the disadvantages of heat delivery via the build platform
do not occur. At the same time, heat delivery is preferably
accomplished not only intermittently, i.e. not only when the
heating element is located (as in the existing art) above the build
layer for a short time, but instead constantly, this being made
possible by the novel continuous working mode. Optimization of heat
input is thereby achieved in simple fashion. At the same time, the
manufacturing process as a whole is improved.
[0016] At the same time, the present invention allows elimination
of the need for a uniform temperature distribution. Because the
manufacturing method has made different degrees of progress at
different sites, different temperatures at different sites can be
advantageous. For example, in one region a preheating temperature
can be advantageous in order to prepare the build material for
imminent local heating; in an adjacent region, on the other hand, a
post-heating temperature can be present, as is advantageous for
achieving certain properties of the already solidified layer, for
example in order to prevent warping.
[0017] Because the heating element is constantly available, a
defined inhomogeneous temperature distribution of this kind can be
implemented in particularly simple fashion. In an advantageous
embodiment of the invention, the heating element contains multiple
regions capable of different temperature control. This is achieved,
for example, with the aid of multiple mutually independently
operable heating modules.
[0018] An additional heat source for furnishing thermal energy can
also be provided, in particular in the form of a radiation source
arranged above the heating element. In this case at least one of
the functional openings is embodied as a heating opening for
additional input of thermal energy. The heating opening can be a
functional opening that already performs another function; for
example, a radiation pass-through already serving as an exposure
opening can serve at the same time as a heating opening.
[0019] An embodiment of the invention in which the heating element
is of substantially plate-shaped configuration has proven to be
particularly advantageous for the transfer of heating energy to the
build material. The plate-like shape of the heating element
simultaneously makes possible a particularly simple embodiment of
the functional openings. Advantageously, the heating element and
build platform are embodied in such a way that they overlap one
another over the largest possible area, preferably completely, or
can be caused during the manufacturing process to overlap one
another over as large an area as possible, preferably
completely.
[0020] In a preferred embodiment of the invention, the heating
element is arranged above the build platform. In a variant, the
heating element is spaced away from the respectively topmost build
layer. Heating is accomplished by thermal radiation. In an
alternative variant, the heating element touches the topmost build
layer. Heating is then accomplished by thermal conduction.
[0021] If the build platform is located inside a process chamber
that is closed in the operating state, the heating element can then
serve as a demarcating wall of the process chamber. In other words,
in this case the process chamber is closed off by the heating
element. The heating element is then a part of the process
chamber.
[0022] The coating opening is always an actual opening in the sense
of a material perforation. For the exposure opening, however, the
heating element need not necessarily be perforated. The exposure
opening can also be embodied as a region of suitable material, in
the basic body of the heating element, which is suitable for the
passage of radiation.
[0023] In a preferred embodiment of the invention, radiation energy
is introduced through the exposure opening but the opening is not
completely illuminated. Instead, a targeted irradiation of the
build material arranged below the opening occurs, within the
boundaries of the opening. The radiation can derive from one or
more radiation sources. For example, for local heating of the build
material one or more laser beams can execute a linear
back-and-forth motion inside the functional opening within the
window furnished by the functional opening, or the laser beams are
guided in defined fashion inside the window on a nonlinear
trajectory, in each case as a function of the structure to be
generated. The radiation is guided with the aid of a suitable
control system. The build material, previously preheated to a
temperature below the processing temperature, becomes locally
heated further. The processing temperature is reached with the aid
of this additional energy input.
[0024] In a simple variant of the invention, the arrangement and
size of the functional openings is unmodifiable. It has proven
advantageous, for example, to use strip-shaped functional openings
that lie parallel to one another. The functional openings are
advantageously arranged in the heating element perpendicularly to
the direction of relative motion, for example perpendicularly to
the X direction or Y direction. Alternatively, it is possible for
the functional openings to be arranged obliquely, i.e. at an angle
to the motion direction. It is advantageous in the context of the
present invention that the shape, arrangement, and size of the
functional openings can be adapted to the special aspects of the
method. Instead of strip-shaped or slit-shaped functional openings,
for example, orifice-shaped functional openings or functional
openings of any other shape can also be provided for for all or for
individual functions.
[0025] In an alternative variant, the shape, arrangement, and/or
size of the functional openings is modifiable. For example, it can
be advantageous to embody the size of the exposure opening
modifiably, in particular when the functional opening serves as an
aperture stop, i.e. to demarcate the cross section of the
introduced radiation. It can likewise be advantageous to embody the
size of the coating opening modifiably, in particular when the
shape and/or size of the opening directly determine the application
location or volume of build material applied for each unit time. A
modification of the functional openings can also be accomplished in
particular during runtime, i.e. while the manufacturing process is
in progress. Additional suitable drive and control devices are then
to be provided for this as applicable.
[0026] It is not only heat input into the build material that is
improved with the present invention. In addition, thanks to a
suitable interaction of the arrangement and size of the functional
openings and the relative motion between the heating element and
build platform, and the manner in which radiation for local
solidification of the build material is furnished and/or guided,
the manufacturing process can also be carried out particularly
efficiently.
[0027] This purpose is served by a central control system for the
manufacturing process using a data model for description of the
object to be manufactured with the aid of the layer building
method. The control system encompasses all relevant operations of
the manufacturing process that proceeds simultaneously at multiple
sites in different manufacturing phases, i.e. manufacturing
processes that have made different degrees of progress. In other
words, control always occurs in accordance with the actual progress
of the manufacturing process, using for this purpose sensor data of
suitable sensors, in particular temperature sensors. The control
system encompasses in particular control of the heating of the
heating element, here optionally the defined control of individual
temperature regions. The control system also encompasses control of
the drive device for the relative motions between the heating
element and the build platform, and control of the furnishing
and/or application device for furnishing and/or applying the build
material, and control of the guided radiation source(s) for local
heating of the build material and, if applicable, control of the
additional radiation source for controlling the temperature of the
build material, as well as also, if applicable, control of the
functional openings of modifiable arrangement and/or size.
[0028] All calculation operations necessary in connection with
control of the layer manufacturing system and with execution of the
method according to the present invention are performed by one or
more data processing units that are embodied for carrying out the
operations. Each of these data processing units preferably has a
number of functional modules, each functional module being embodied
to carry out a specific function or a number of specific functions
in accordance with the method described. The functional modules can
be hardware modules or software modules. In other words, insofar as
it relates to the data processing unit the invention can be
realized either in the form of computer hardware or in the form of
computer software, or in a combination of hardware and software. If
the invention is realized in the form of software, i.e. as a
computer program product, all the functions described are
implemented by computer program instructions when the computer
program is executed on a computer having a processor. The computer
program instructions are realized in any programming language in a
manner that is known per se, and can be furnished to the computer
in any form, for example in the form of data packets that are
transferred via a computer network, or in the form of a computer
program product stored in a diskette, a CD-ROM, or another data
medium.
[0029] Other features which are considered as characteristic for
the invention are set forth in the appended claims.
[0030] Although the invention is illustrated and described herein
as embodied in an apparatus and a method for manufacturing
three-dimensional objects, it is nevertheless not intended to be
limited to the details shown, since various modifications and
structural changes may be made therein without departing from the
spirit of the invention and within the scope and range of
equivalents of the claims.
[0031] The construction and method of operation of the invention,
however, together with additional objects and advantages thereof
will be best understood from the following description of specific
embodiments when read in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0032] FIG. 1 is a schematic diagram of an apparatus according to
the invention having a highly simplified process chamber depicted
in section;
[0033] FIG. 2 is a schematic plan view of a heating element
disposed above a build platform; and
[0034] FIGS. 3A-3E are simplified sectioned depictions of layers of
an object to be built up, in different manufacturing phases.
DETAILED DESCRIPTION OF THE INVENTION
[0035] All the figures show the invention not to scale, merely
schematically, and only with its essential constituents. Identical
reference characters correspond to elements having an identical or
comparable function.
[0036] Referring now to the figures of the drawings in detail and
first, particularly to FIGS. 1 and 2 thereof, there is shown an
apparatus 1 for laser sintering, more specifically an apparatus for
manufacturing at least one three-dimensional object by selective
solidification of a build material applied in layers. The invention
is not, however, limit to this specific method. The invention is
also applicable to other additive production methods, for example
laser melting, mask sintering, drop on powder/drop on bed,
stereolithography, and the like.
[0037] An orthogonal coordinate system (X, Y, Z) is utilized in the
description of the invention.
[0038] The apparatus 1 for laser sintering encompasses a build
platform 2, disposed in an X-Y plane, on which a three-dimensional
object 3 is generated in layers in known fashion. A build material
4 that is suitable is a plastic powder. After production of a layer
n, in order to produce a new layer n+1 the build platform 2 having
the already created and hardened layers is displaced downward over
a specific travel length. This purpose is served by a drive device
5 for generating a relative motion in a Z direction, i.e.
perpendicularly to the build plane, between the build platform 2
and a heating element 6 described later in further detail. The
drive device 5 is, for example, an electric motor.
[0039] Between solidification of a layer n and application of new
build material 4 for a subsequent layer n+1, provision can be made
to remove excess build material 4 from the build platform 2. In
this case a device suitable for this is provided, for example in
the form of a non-illustrated wiping blade or the like, which
advantageously is connected to or interacts with the heating
element 6.
[0040] The apparatus 1 encompasses at least one radiation source 7
that furnishes radiation energy for local heating of the build
material 4 in order to selectively solidify the latter. The at
least one radiation source 7 is, for example, a laser that delivers
a laser beam 8 in a guided fashion.
[0041] The apparatus 1 furthermore encompasses at least one
furnishing and/or application device 9 with which the build
material 4 is furnished and/or is applied onto the build platform 2
or onto a build layer that is already present. The furnishing
and/or application device 9 is, for example, a device for applying
a powder charge. The furnishing and/or application device 9 is
connected to a corresponding control system 10 that controls the
application of material.
[0042] The apparatus 1 further encompasses the heating element 6
(already mentioned above) for introducing thermal energy into build
material 4, which element constantly at least partly overlaps the
build platform 2 during the manufacturing process. The heating
element 6 is of a substantially plate-shaped configuration. It is
arranged above the build platform 2, being spaced away from the
respectively topmost build layer. The spacing is typically between
100 .mu.m and 10 mm. The heating of the build material 4 is
accomplished by thermal radiation 11 delivered by the heating
element 6, as depicted symbolically in FIGS. 1 and 3.
[0043] The build platform 2 is located inside a process chamber 12,
closed in the operating state, that is merely schematically
indicated in FIG. 1. The heating element 6 serves here as a
demarcation wall of the process chamber 12. More precisely, the
heating element 6 is embodied as part of an upper cover 13 of the
process chamber 12.
[0044] The apparatus 1 further encompasses a drive device 15 for
generating a relative motion between the build platform 2 and the
heating element 6 in the X and/or Y direction, i.e. in a layer
direction. The drive device 15 is, for example, an electric motor.
The two drive devices 5, 15 are connected to corresponding drive
control systems 16, 17.
[0045] In the exemplifying embodiment described here, the drive
device 15 moves the build platform 2 relative to the stationary
heating element 6. The principal motion direction is the X
direction. In the simplest case, the motion of the build platform 2
is limited to this principal motion direction. If necessary or
advantageous for the manufacturing process, the motion in the X
direction can be overlaid by a motion of the build platform 2 in
the Y direction.
[0046] The heating element 6 contains at least two, in the example
depicted in FIG. 1 three simultaneously usable functional openings
18, 19, 20 spaced apart from one another. The functional openings
18, 19, 20 are slit-shaped or strip-shaped, elongated rectangular,
and lie parallel to one another and perpendicular to the principal
motion direction, here the X direction. One of the functional
openings is embodied as a material pass-through 18 and another of
the functional openings as a radiation pass-through 19. During the
production of the object 3, both the build material 4 and radiation
energy, here in the form of the laser beam 8, are allowed to pass
simultaneously through functional openings 18, 19.
[0047] Expressed differently, the one functional opening is
embodied as a coating opening 18 for the application of the build
material 4 onto the build platform 2 or onto a build layer that is
already present, and the other functional opening is embodied as an
exposure opening 19 for simultaneous introduction of the radiation
energy of the at least one radiation source 7 into the applied
build material 4 in order to solidify the build material 4.
[0048] Radiation energy for local heating of the build material 4
is introduced by guiding the laser beam 8 through the exposure
opening 19 on a defined path. The laser beam 8 is guided with the
aid of a suitable drive and a control device 21.
[0049] The heating element 6 contains multiple heating modules 23,
to which control can be applied mutually independently and which
are arranged between or next to functional openings 18, 19, 20. All
the heating modules 23 of the heating element 6 are connected to a
heating control system 24. The working principle of the heating
modules 23 is based, for example, on the principle of electrical
induction. Other suitable functioning modes for the heating modules
are likewise possible.
[0050] In the example illustrated in FIG. 1, the apparatus 1 also
encompasses an additional heat source in the form of a radiation
source 25, arranged above the heating element 6, for furnishing
thermal energy. The additional radiation source 25 is, for example,
an infrared radiator that delivers infrared radiation 26. A
suitable control system 27 is provided for this radiation source as
well. The additional radiation source 25 has associated with it a
dedicated functional opening 20 that thus serves as a heating
opening.
[0051] A central control system 28 is responsible for controlled
execution of the manufacturing method. The control system 28
encompasses for this purpose all the relevant control sub-systems
10, 16, 17, 21, 24, 27.
[0052] Various phases of manufacture will be described below with
reference to FIGS. 3A-3E. What is used here is a heating element
6', different from heating element 6 shown in FIGS. 1 and 2, which
possesses three functional openings, namely two coating openings
18, 18' and one exposure opening 19 arranged between the coating
openings 18, 18'.
[0053] In FIG. 3A, the build platform 2, driven by the drive device
15, moves through in the X direction beneath first coating opening
18 of the heating element 6. The build material 4 for a layer n
becomes deposited onto the build platform 2.
[0054] In FIG. 3B, the build platform 2 moves farther in the X
direction. The build material 4 that was applied shortly beforehand
becomes preheated, by the heating module 23 arranged between the
first coating opening 18 and the exposure opening 19 in the basic
body of the heating element 6, to a temperature below the sintering
temperature. At the same time, in an adjacent object region
preheated just previously, additional thermal energy is introduced
with the aid of laser beam 8 through the exposure opening 19, with
the result that the powder particles fuse.
[0055] In FIG. 3C, the build platform 2 moves farther in the X
direction. Before the build platform 2 reaches the second coating
opening 18', it is moved a requisite travel distance downward in
the Z direction, driven by the drive device 5. The build material 4
for a further layer n+1 is applied through second coating opening
18'. This object region had just previously been heated again by a
further heating module 23' arranged between the exposure opening 19
and the second coating opening 18'.
[0056] In FIG. 3D, the build platform 2 has reached its one
reversal point. Layers n and n+1 have been generated. Because there
is no longer an exposure opening 19 located above the build
platform 2, at this moment laser irradiation is no longer taking
place. The application of the build material 4 also occurs only as
long as at least one of the two coating openings 18, 18' is
arranged above the build platform 2.
[0057] In FIG. 3E, the build platform 2 moves through beneath the
heating element 6 in the X direction, oppositely to the first
motion. With the aid of the second coating opening 18', a new
application of material for the next layer n+2 has already
occurred, as has preheating with the aid of a third heating module
23''. The build platform 2, driven by the drive device 5, has
previously been moved down again a necessary distance in the Z
direction. A local irradiation with the laser beam 8 occurs through
the exposure opening 19 in order to solidify the structure to be
generated. First the heating module 23 serves for post-heating.
Upon a further motion of the build platform 2, an application of
material for layer n+3 will occur shortly through the first coating
opening 18.
[0058] All features presented in the specification, the claims
below, and the drawings can be essential to the invention both
individually and in any combination with one another.
[0059] The following is a summary list of reference numerals and
the corresponding structure used in the above description of the
invention: [0060] 1 Apparatus for laser sintering [0061] 2 Build
platform [0062] 3 Object [0063] 4 Build material [0064] 5 Drive
direction (Z) [0065] 6 Heating element [0066] 7 Radiation source,
laser [0067] 8 Laser beam [0068] 9 Furnishing/application device
[0069] 10 Control system for material application [0070] 11 Thermal
radiation [0071] 12 Process chamber [0072] 13 Cover [0073] 14
(unassigned) [0074] 15 Drive device (X/Y) [0075] 16 Drive control
system (Z) [0076] 17 Drive control system (X/Y) [0077] 18
Functional opening, material pass-through, coating opening [0078]
19 Functional opening, radiation pass-through, exposure opening
[0079] 20 Functional opening, heating opening [0080] 21 Drive and
control device for laser [0081] 22 (unassigned) [0082] 23 Heating
module [0083] 24 Heating control system [0084] 25 Radiation source,
IR radiator [0085] 26 Infrared radiation [0086] 27 Control system
for additional heating [0087] 28 Central control system
* * * * *