U.S. patent application number 10/902934 was filed with the patent office on 2005-01-06 for apparatus for forming a three-dimensional product.
This patent application is currently assigned to MINOLTA CO., LTD.. Invention is credited to Kubo, Naoki, Tochimoto, Shigeaki.
Application Number | 20050001356 10/902934 |
Document ID | / |
Family ID | 26544590 |
Filed Date | 2005-01-06 |
United States Patent
Application |
20050001356 |
Kind Code |
A1 |
Tochimoto, Shigeaki ; et
al. |
January 6, 2005 |
Apparatus for forming a three-dimensional product
Abstract
In a 3D product forming apparatus, a nozzle head includes
nozzles that respectively jet binders colored in yellow, magenta,
cyan, and a nozzle that jets a binder colored in white. A powder
layer can be formed on a product forming stage, and the binders are
jetted onto the formed powder layer from the nozzle head. At a
predetermined region in the powder layer, the powder is bound by
the binders. The binders are jetted each time when a powder layer
is laminated in forming a plurality of successively laminated
powder layers, thereby to form a 3D product on the product forming
stage. This allows the product to be colored as well in the product
forming process. As a result, 3D products colored in various colors
can be created in a short time and at a low cost.
Inventors: |
Tochimoto, Shigeaki; (Osaka,
JP) ; Kubo, Naoki; (Nishinomiya-Shi, JP) |
Correspondence
Address: |
McDermott Will & Emery LLP
600 13th Street, N.W.
Washington
DC
20005-3096
US
|
Assignee: |
MINOLTA CO., LTD.
Osaka
JP
|
Family ID: |
26544590 |
Appl. No.: |
10/902934 |
Filed: |
August 2, 2004 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10902934 |
Aug 2, 2004 |
|
|
|
09662150 |
Sep 14, 2000 |
|
|
|
6799959 |
|
|
|
|
Current U.S.
Class: |
264/308 ;
425/130 |
Current CPC
Class: |
B29C 64/165 20170801;
B29K 2995/0021 20130101; B29C 37/0003 20130101; B29C 41/12
20130101; B29C 64/35 20170801 |
Class at
Publication: |
264/308 ;
425/130 |
International
Class: |
B29C 031/08 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 14, 1999 |
JP |
P11-260394 |
May 24, 2000 |
JP |
P2000-153394 |
Claims
What is claimed is:
1. An apparatus for forming a three-dimensional product by applying
binder to powder material to form bound bodies successively, said
bound bodies corresponding to sectional data blocks which are
produced by slicing an original object with parallel planes, said
apparatus comprising: a layer forming mechanism for forming a layer
of said powder material; an applying head for applying plural kinds
of materials to said layer, said plural kinds of materials
including at least one kind of binder; and a controller for
controlling said applying head to apply said plural kinds of
materials selectively to a predetermined region on said layer.
2. The apparatus of claim 1, wherein said applying head applies one
material included in said plural kinds of materials after another
material, and said another material becomes stable faster than said
one material after applied to said layer.
3. The apparatus of claim 1, wherein said applying head applies
binder and ink.
4. The apparatus of claim 3, wherein said applying head applies
said binder after said ink.
5. The apparatus of claim 1, wherein said applying head applies a
plurality of binders to said predetermined region, said plurality
of binders have different colors from one another.
6. The apparatus of claim 5, wherein said plurality of binders
include three binders which are colored with three primary colors,
respectively.
7. The apparatus of claim 5, wherein said plurality of binders
include a binder colored with white.
8. The apparatus of claim 5, wherein said plurality of binders
include a binder which is colorless and transparent, or milky
white.
9. The apparatus of claim 5, wherein said plurality of binders
include a colorless and transparent binder and a binder colored
with a color which is different from a color of said power
material.
10. The apparatus of claim 5, wherein said predetermined region is
include a coloring region and a non-coloring region, and said
powder material is bound with said plurality of binders selectively
in said coloring region and with one of said plurality of binders
in said non-coloring region.
11. The apparatus of claim 10, wherein said coloring region
includes a region which appears on surface of said
three-dimensional product.
12. The apparatus of claim 10, further comprising: a plurality of
tanks for containing said plurality of binders and supplying said
plurality of binders to said applying head; and detectors for
detecting amount of rest of said plurality of binders in said
plurality of tanks, wherein a binder which is remaining
comparatively more in one of said plurality of tanks is applied to
said non-coloring region.
13. The apparatus of claim 1, wherein said applying head applies a
plurality of binders which give different senses of mass from one
another to said three-dimensional product.
14. The apparatus of claim 5, wherein said applying head comprises
a plurality of nozzles which jet said plurality of binders,
respectively.
15. The apparatus of claim 1, wherein said powder material is
white.
16. The apparatus of claim 15, wherein said powder material is made
of white pigment.
17. The apparatus of claim 15, wherein said powder material is
mixed with powder of white pigment.
18. The apparatus of claim 17, wherein particle size of said powder
of white pigment is smaller than particle size of said powder
material.
19. The apparatus of claim 15, wherein said powder material
contains white pigment.
20. The apparatus of claim 15, wherein said powder material
includes white pigment, and said white pigment is titanium
oxide.
21. The apparatus of claim 1, wherein said powder material is
colorless and transparent.
22. The apparatus of claim 1, wherein amount of said at least one
kind of binder applied to said predetermined region is constant per
unit area of main surface on said layer of said powder
material.
23. The apparatus of claim 1, wherein said layer forming mechanism
comprises: powder supplier for forming a left-side heap and a
right-side heap of said powder material on left and right sides of
a space where said three-dimensional product is formed; and a
left-side powder spreading member and a right-side powder spreading
member provided on left and right sides of said applying head,
respectively, in case of moving said applying head from left to
right, said right-side powder spreading member spreads said
left-side heap to right direction to form a layer of said powder
material, and in case of moving said applying head from right to
left, said left-side powder spreading member spreads said
right-side heap to left direction to form a layer of said powder
material.
24. The apparatus of claim 23, wherein said right-side powder
spreading member and said left-side powder spreading member move up
and down alternately, and while one powder spreading member is
forming a layer of said powder material, another spreading member
retreats upward.
25. A method of forming a three-dimensional product by applying
binder to powder material to form bound bodies successively, said
bound bodies corresponding to sectional data blocks which are
produced by slicing an original object with parallel planes, said
method comprising the steps of: a) forming a layer of said powder
material; b) applying plural kinds of materials selectively to a
predetermined region on said layer, said plural kinds of materials
including at least one kind of binder; and c) repeating said steps
a) and b).
26. An apparatus for forming a three-dimensional product by
applying binder to powder material, said three-dimensional product
corresponding to an original object, said apparatus comprising: a
layer forming mechanism for forming layers of powder material
successively, said powder material having thermo plasticity; an
applying head for applying material including binder to each layer
after said layer forming mechanism formed said each layer to form
bound bodies successively, said bound bodies corresponding to
sections which are sliced off from said original object with
parallel planes; and a heater for heating a three-dimensional
product formed by said layer forming mechanism and said applying
head.
27. The apparatus of claim 26, wherein said heater comprises a lamp
for applying light to said three-dimensional product.
28. A method of forming a three-dimensional product by applying
binder to powder material, said three-dimensional product
corresponding to an original object, said method comprising the
steps of: a) forming a layer of powder material which has thermo
plasticity; b) applying material including binder to said layer and
forming a bound body corresponding to a section of said original
object; c) repeating said steps a) and b), to thereby laminate
bound bodies and form a three-dimensional product, said bound
bodies corresponding to sections which are sliced off from said
original object with parallel planes; and d) heating said
three-dimensional product.
29. The method of claim 28, wherein light is applied to said
three-dimensional product in said step d).
30. The method of claim 28, wherein said powder material is made of
thermoplastic resin.
31. The method of claim 30, wherein said powder material is toner
for electrophotography.
32. The method of claim 28, wherein said powder material is
colorless and transparent, or white.
Description
[0001] This application is based on applications Nos.
11-260394(1999) and 2000-153394 filed in Japan, the contents of
which are hereby incorporated by reference. BACKGROUND OF THE
INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a technique about forming a
three-dimensional (3D ) product, and more particularly to a
technique for forming a 3D product by imparting a binding material
to bind powder.
[0004] 2. Description of the Background Art
[0005] Hitherto, a technique is known in which a product being a 3D
model of a 3D original object is created by successively binding,
with a binding material, thin powder layers corresponding to
respective cross sections obtained by cutting the 3D original
object with a plurality of parallel planes.
[0006] Such a technique can be utilized for making a component
sample called rapid prototyping and is disclosed, for example, in
Japanese Patent No. 2729110. Specific procedures for forming a 3D
product will be described hereafter.
[0007] First, a thin powder layer is spread uniformly on a flat
surface by a blade mechanism. Next, a nozzle head is allowed to
scan a predetermined region on the powder layer to jet a binder
(binding material). The powder material on a region where the
binder has been jetted is brought into a joined state and is
further bound with a lower layer that has already been formed.
Then, until the whole product is completed, powder layers are
successively laminated on upper parts and the step of jetting the
binder is repeated. Finally, the region to which the binder has not
adhered is separated by dropping it in taking out the product from
the forming apparatus because the powder in that region is
individually in an independent state, namely in a mutually
non-bound state. The above completes a desired 3D product.
[0008] However, by the above-mentioned technique, only a product in
which the whole has a single property (sense of mass, color) can be
obtained. If the product must be colored, the coloring must be
carried out manually in the subsequent step, thereby requiring time
and costs. Further, by manual coloring, it is generally difficult
to draw with certainty a desired pattern and others at a
predetermined position of the 3D product.
[0009] On the other hand, the 3D product immediately after the
formation may have a small strength because the product is formed
only by a binding force generated by the binder, so that the
product may be broken depending on how the product is handled with.
Conventionally, therefore, the strength has been enhanced by
allowing a wax or the like to penetrate through gaps among powder
particles of the 3D product after the formation. In reality,
however, such a step requires labor and time.
SUMMARY OF THE INVENTION
[0010] The present invention is directed to an apparatus for
forming a three-dimensional product by applying binder to powder
material to form bound bodies successively, the bound bodies
corresponding to sectional data blocks which are produced by
slicing an original object with parallel planes.
[0011] According to the present invention, the apparatus comprises:
a layer forming mechanism for forming a layer of the powder
material; an applying head for applying plural kinds of materials
to the layer, the plural kinds of materials including at least one
kind of binder; and a controller for controlling the applying head
to apply the plural kinds of materials selectively to a
predetermined region on the layer.
[0012] Since the apparatus of the present invention can give
various properties to three-dimensional products during the process
of forming the three-dimensional products, three-dimensional
products having various properties can be formed in a short time
and at a low cost.
[0013] In an aspect of the present invention, the applying head
applies binder and ink.
[0014] In another aspect of the present invention, the applying
head applies a plurality of binders to the predetermined region,
the plurality of binders have different colors from one
another.
[0015] Preferably, the powder material is white.
[0016] The apparatus of the present invention can form
three-dimensional products colored in various modes.
[0017] In another aspect of the present invention, the applying
head applies a plurality of binders which give different senses of
mass from one another to the three-dimensional product.
[0018] The apparatus of the present invention can form
three-dimensional products having various senses of mass in a short
time and at a low cost.
[0019] The present invention is also directed to another apparatus
for forming a three-dimensional product by applying binder to
powder material, the three-dimensional product corresponding to an
object.
[0020] According to the present invention, the apparatus comprises:
a layer forming mechanism for forming layers of powder material
successively, the powder material having thermo plasticity; an
applying head for applying material including binder to each layer
after the layer forming mechanism formed the each layer to form
bound bodies successively, the bound bodies corresponding to
sections which are sliced off from the original object with
parallel planes; and heater for heating a three-dimensional product
formed by the layer forming mechanism and the applying head.
[0021] The apparatus of the present invention can easily enhance
the strength of the three-dimensional products.
[0022] The present invention is also directed to a method of
forming a three-dimensional product.
[0023] These and other objects, features, aspects, and advantages
of the present invention will become more apparent from the
following detailed description of the present invention when taken
in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a schematic view illustrating a 3D product forming
apparatus according to the first embodiment;
[0025] FIG. 2 is a flowchart for describing an overall operation of
the 3D product forming apparatus;
[0026] FIG. 3A is a view showing an example of model data, FIG. 3B
is a view showing an example of a cross-section body, and FIG. 3C
is a view showing an example of cross-section data;
[0027] FIG. 4A is a view showing an example of model data, FIG. 4B
is a view showing an example of a cross-section body, and FIG. 4C
is a view showing an example of cross-section data (configuration
data);
[0028] FIGS. 5A to 5C are conceptual views for describing the
operation of the 3D product forming apparatus;
[0029] FIG. 6A is a cross-section view illustrating a 3D product
obtained in the first embodiment, and FIG. 6B is a partial enlarged
view;
[0030] FIG. 7 is a view illustrating an example of gray scale
(density scale) representation for cyan color;
[0031] FIG. 8 is a view illustrating an example of representation
in which the color changes from faint cyan to faint yellow;
[0032] FIGS. 9A and 9B are views illustrating an example of
coloring;
[0033] FIG. 10 is a schematic view illustrating a 3D product
forming apparatus according to the second embodiment;
[0034] FIG. 11 is a view illustrating a partial cross section of a
tank part;
[0035] FIG. 12 is a flowchart for describing an overall operation
of the 3D product forming apparatus;
[0036] FIG. 13 is a schematic view illustrating a 3D product
forming apparatus according to the third embodiment;
[0037] FIG. 14 is a flowchart for describing an overall operation
of the 3D product forming apparatus;
[0038] FIGS. 15A to 15D are conceptual views for describing the
operation of the 3D product forming apparatus;
[0039] FIG. 16 is a schematic view illustrating a 3D product
forming apparatus according to the fourth embodiment;
[0040] FIG. 17 is a flowchart showing a flow of ink and binder
jetting operations in the fourth embodiment;
[0041] FIG. 18 is a flowchart showing a flow of processes after the
formation of a product is completed;
[0042] FIG. 19 is a view showing an example of an internal
construction of a fixing apparatus;
[0043] FIG. 20 is a view showing another example of an internal
construction of a fixing apparatus;
[0044] FIG. 21 is a view illustrating a part of a 3D product
forming apparatus having a fixing part; and
[0045] FIGS. 22 to 24 are views illustrating how the 3D product
forming apparatus shown in FIG. 21 operates.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0046] 1. First Preferred Embodiment
[0047] 1-1. Construction of Principal Part of 3D Product Forming
Apparatus FIG. 1 is a schematic view showing a 3D product forming
apparatus 100 according to the first embodiment. Here, in FIG. 1,
XYZ directions determined for the sake of explanation are shown
with arrows.
[0048] The 3D product forming apparatus 100 comprises a controlling
part 10 as well as a binder applying part 20, a product forming
part 30, a powder supplying part 40, a powder spreading part 50,
and an infrared lamp 60, which are electrically connected with the
controlling part 10, respectively.
[0049] The controlling part 10 includes a computer 11 and a drive
controlling part 12 electrically connected with the computer
11.
[0050] The computer 11 is a general desk-top type computer or the
like which is constructed to include a CPU, a memory, and others in
the inside thereof. This computer 11 turns the 3D shape of an
original object into data as model data, and outputs cross-section
data, which is obtained by slicing the product into thin
cross-section bodies of many parallel layers, to the drive
controlling part 12.
[0051] The drive controlling part 12 functions as controlling means
for respectively driving the binder applying part 20, the product
forming part 30, the powder supplying part 40, and the powder
spreading part 50. Upon obtaining the cross section data from the
computer 11, the drive controlling part 12 collectively controls
the operations of successively forming a powder bound body (bound
layer) for each layer of the powder material in the product forming
part 30 by giving driving instructions to each of the
aforementioned parts on the basis of the cross section data.
[0052] The binder applying part 20 includes a tank part 21 for
accommodating a liquid binder (a general adhesive may be used), a
nozzle head 22 for jetting the binder in the tank part 21, an
XY-direction moving part 23 for moving the nozzle head 22 in a
horizontal XY-plane, and a driving part 24 for driving the
XY-direction moving part 23.
[0053] The tank part 21 includes a plurality of tanks (four tanks
in this example) 21a to 21d for accommodating binders of mutually
different colors. Specifically, the tanks 21a to 21d accommodate
binders (hereafter referred to as colored binders) colored in three
primary colors of Y (yellow), M (magenta), C (cyan), and W (white),
respectively. Here, it is preferable to use colored binders whose
colors do not change even if the binders are bound with the powder,
and whose colors do not change or fade even after a long time
passes.
[0054] The nozzle head 22 is fixed to a lower part of the
XY-direction moving part 23, and is integral with the XY-direction
moving part 23 to be freely movable in the XY-plane. Further, the
nozzle head 22 includes the same number of jetting nozzles 22a to
22d as the tanks 21a to 21d of the tank part 21. The jetting
nozzles 22a to 22d are connected to the tanks 21a to 21d,
respectively, with four tubes 25. Each of the nozzles 22a to 22d is
a nozzle that jets (erupts) each binder as minute liquid drops, for
example, by an ink jet system or the like. The jetting of the
binder by each of the jetting nozzles 22a to 22d is individually
controlled by the drive controlling part 12, and the binder jetted
from each of the jetting nozzles 22a to 22d adheres to a powder
layer of the product forming part 30 disposed at a place opposite
to the nozzle head 22.
[0055] The XY-direction moving part 23 includes a moving part main
body 23a and a guide rail 23b. The moving part main body 23a is
capable of reciprocal movement in the X-direction along the guide
rail 23b, and is capable of reciprocal movement in the Y-direction.
Therefore, the XY-direction moving part 23 makes the nozzle head 22
capable of moving in a plane defined by the X-axis and the Y-axis.
In other words, on the basis of the driving instructions from the
drive controlling part 12, the nozzle head 22 can be allowed to
move to an arbitrary position within a drive range in the
plane.
[0056] The product forming part 30 includes a product forming main
body 31 having a recessed part at the center thereof, a product
forming stage 32 disposed in the inside of the recessed part of the
product forming main body 31, a Z-direction moving part 33 for
moving the product forming stage 32 in the Z-direction, and a
driving part 34 for driving the Z-direction moving part 33.
[0057] The product forming main body 31 serves to provide a work
area for creating a 3D product. Further, the product forming main
body 31 has, at an upper portion thereof, a provisional powder
placing part 31b for temporarily holding the powder supplied from
the powder supplying part 40.
[0058] The product forming stage 32 has a rectangular shape in an
XY-cross section, and its side surface is in contact with a
vertical inner wall 31 a of the recessed part in the product
forming main body 31. A three-dimensional space WK having a
rectangular parallelopiped shape, which is formed by the product
forming stage 32 and the vertical inner wall 31a of the product
forming main body 31, defines a base space for forming a 3D
product. Namely, the binders jetted from the jetting nozzles 22a to
22d create the 3D product by joining the powder on the product
forming stage 32.
[0059] The Z-direction moving part 33 has a supporting rod 33a that
is linked to the product forming stage 32. Movement of the
supporting rod 33a in a vertical direction caused by the driving
part 34 allows Z-direction movement of the product forming stage 32
linked to the supporting rod 33a.
[0060] The powder supplying part 40 includes a tank part 41, a
shutting plate 42 disposed at an outlet of the tank part 41, and a
driving part 43 for sliding the shutting plate 42 by instructions
from the drive controlling part 12.
[0061] The tank part 41 accommodates a white powder. This powder
serves as a material in forming a 3D product, and may be, for
example, a (cellulose)-starch powder, a gypsum powder, a resin
powder, or the like.
[0062] The shutting plate 42 is adapted to be capable of sliding in
the horizontal direction (X-direction), and performs or stops the
supply of the powder, which is accommodated in the tank part 41, to
the provisional powder placing part 31b of the product forming part
30.
[0063] The powder diffusing part 50 includes a blade 51, a guide
rail 52 for regulating the operation of the blade 51, and a driving
part 53 for moving the blade 51.
[0064] The blade 51 is long in the Y-direction and has an edge-like
shape whose lower tip end is sharp. The blade 51 has a length in
the Y-direction such that the length can cover the width in the
Y-direction in the three-dimensional space WK. Here, a vibration
mechanism for giving a minute vibration to the blade may be added
so that the blade 51 can smoothly diffuse the powder.
[0065] The driving part 53 has a vertical driving part 53a for
moving the blade 51 up and down in the vertical direction
(Z-direction) and a horizontal driving part 53b for reciprocating
the blade 51 in the horizontal direction (X-direction). The
vertical driving part 53a and the horizontal driving part 53b being
driven on the basis of instructions from the drive controlling part
12 allow movement of the blade 51 in the X-direction and in the
Z-direction.
[0066] The infrared lamp 60 is disposed for promoting the binding
of the powder to which the binder is applied, by evaporating the
moisture or solvent contained in the binder. The infrared lamp 60
is turned on and off by instructions from the drive controlling
part 12. Further, if the product forming apparatus is constructed
to use a thermosetting binder, the infrared lamp 60 functions as
means for setting (hardening) the binder.
[0067] 1-2. Operation of 3D Product Forming Apparatus
[0068] FIG. 2 is a flowchart for describing an overall operation of
the 3D product forming apparatus 100. Hereafter, the basic
operations of the apparatus 100 will be described with reference to
FIG. 2.
[0069] In step S1, the computer 11 creates model data that
represent the 3D original object whose surface has been subjected
to color patterning and others. As the model data that constitutes
a basis for forming a 3D product, one can make use of a
three-dimensional color model data that is created by a general
three-dimensional CAD modeling software. Further, it is possible to
utilize data and texture of a three-dimensional configuration
measured by a 3D configuration input device.
[0070] In some model data, color information is imparted only to
the surface of a 3D model, while in other model data, color
information is imparted to the inside of the model as well. Even in
the latter case, it is possible to use only the color information
on the model surface in forming a 3D product, or alternatively it
is possible to use the color information on the inside of the model
as well. For example, in forming a 3D product such as a human body
model, it may be desired to color each internal organ with a
different color. In such a case, the color information on the
inside of the model is utilized.
[0071] In step S2, cross-section data for each cross section is
created which is obtained by slicing the 3D original object in a
horizontal direction from the above-mentioned model data. The model
data is sliced at a pitch corresponding to the thickness of one
powder layer of lamination to produce cross-section bodies, and the
configuration data and the color data that show a region where the
cross section exists are created as cross-section data. Here, the
slicing pitch may be made changeable within a predetermined range
(range of thickness that can bind the powder).
[0072] FIGS. 3A to 3C are views showing how an example of
cross-section data is created in step S2. Referring to FIGS. 3A and
3B, a cross-section body including color information is cut out
from the model data, and divided into many small parts in a
lattice-like configuration. This is treated in the same manner as a
bit map of a two-dimensional image, and is converted into bit map
information for each color, as illustrated in FIG. 3C. This bit map
information is information in which gray scale and others are taken
into account. Referring to FIG. 3C, the configuration data is a
data that indicates a region where the cross section exits, and Y
data, C data, M data, and W data correspond to the color data.
[0073] Here, in this embodiment, since the color of the powder is
white, white parts need not be colored. However, in order to form a
3D product, binders are required, so that the white binder is
applied to these parts in this embodiment, and W data is imparted
to these parts. Also, if the inside of the 3D model has no color
information, the W data is imparted also to the parts corresponding
to the inside of the 3D model. Thus, if an OR (logical sum) of the
YCMW data is taken, the entire surface of the cross section is
filled.
[0074] FIGS. 4A to 4C are views showing how an example of
cross-section data is created in step S2 in the same manner as in
FIGS. 3A to 3C. Here, in FIG. 4C, illustration of the color data is
omitted, and the configuration data is illustrated only for a
region where the cross section exists. In FIG. 4C, the parts that
do not contribute to the 3D product formation in the model data,
i.e. the parts corresponding to the inner regions that do not
appear to the outside, are deleted from the configuration data as
the parts that do not need to be formed. Thus, in the parts that do
not need to be formed, the operation of binding the powder with the
binders is not carried out, thereby saving the binders.
[0075] In step S3, information on the lamination thickness of the
powder in forming a 3D product of the 3D original object (i.e.
slice pitch in creating the cross section data) and on the number
of laminates (the number of cross section data sets) is input from
the computer 11 to the drive controlling part 12.
[0076] In the next step S4 and thereafter, the drive controlling
part 12 controls each part to perform the operations. FIGS. 5A to
5C are conceptual views for describing these operations. Hereafter,
the descriptions will be made with reference to FIGS. 5A to 5C.
[0077] In step S4, the product forming stage 32 is lowered by a
predetermined distance in the direction of arrow DN illustrated in
FIG. 5A by the Z-direction moving part 33 and held in order to form
a bound body of the N-th powder layer (N=1, 2, . . . ) on the
product forming stage 32. The distance for lowering is a distance
corresponding to the above-mentioned laminate thickness input from
the computer 11. This forms a space SP for forming one new powder
layer on the powder layers that have been laminated on the product
forming stage 32 and completed the necessary binding. However, in
the case of N=1, it corresponds to the first layer, so that the
space SP is formed immediately above the upper surface of the
product forming stage 32.
[0078] In step S5, a powder is supplied which serves as the
material for forming the 3D product. In this step, the shutting
plate 42 of the powder supplying part 40 is slid from the closed
position, as shown in FIG. 5A, to allow the powder in the tank 41
to fall at a predetermined amount onto the provisional powder
placing part 31b of the product forming main body 31. This
predetermined amount is set to be a little larger than the volume
of the above-mentioned space SP (the amount of the powder needed
for forming the product). After the supply of the predetermined
amount of powder is completed, the shutting plate 42 returns to the
closed position, and stops the supply of the powder.
[0079] In step S6, a thin layer of the powder supplied in the step
S5 is formed. Here, as illustrated in FIGS. 5A and 5B, the powder
deposited on the provisional powder placing part 31b is conveyed
(transported) to the space SP on the product forming stage 32 by
the blade 51 moving in the X-direction, thereby to form a thin
uniform powder layer. At this time, the lower tip end of the blade
51 is moved along the uppermost surface 31c of the product forming
main body 31. This allows precise formation of the thin powder
layer having a predetermined thickness. Here, the residual powder
is collected and can be used again. After the powder layer is
formed, the blade 51 is separated from the uppermost surface 31c by
the vertical driving part 53a (See FIG. 1), and is allowed to pass
above the powder layer by the horizontal driving part 53b to return
to the initial position.
[0080] In step S7, the nozzle head 22 is moved in the XY-plane, as
shown in FIG. 5C, by driving the XY-direction moving part 23 in
accordance with the configuration data and the color data prepared
in the step S2. At this time, the scanning time is shortened by
allowing the nozzle head 22 to scan only the region where the
configuration data exists. While the nozzle head 22 is moving, each
of the jetting nozzles 22a to 22d is suitably allowed to jet a
colored binder on the basis of the color data. This creates a bound
body 81 of the powder. Here, the powder 82 to which the binders
have not been applied is kept in an individually independent
state.
[0081] In this step, in jetting the binders to the parts
corresponding to the surface parts of the 3D product, control is
made to selectively jet the colored binders of Y, M, C, and W on
the basis of the color data derived from the 3D original object.
This makes it possible to form a colored product during the process
of forming the 3D product. On the other hand, the parts of the 3D
product that need not be colored (non-coloring region) are formed
by jetting the W-colored binder that does not hinder the colored
state of the colored parts.
[0082] Further, in order to ensure the strength of the 3D product
by uniformizing the spread of the binders adhering to the powder
layer, it is preferable to uniformly apply the same amount of the
powders per unit area to the parts to be formed. For example, the
same amount of the binders can be applied uniformly per unit area
if the product obtained by multiplying the moving speed of each of
the nozzles 22a to 22d by the XY-direction moving part 23 with the
amount of the binder (for example, the number of liquid drops of
the binder) jetted from each of the nozzles 22a to 22d per unit
period of time is made constant.
[0083] After the jetting of the binders is completed, the operation
of jetting the binders is stopped, and the XY-direction moving part
23 is driven to allow the nozzle head 22 to return to the initial
position.
[0084] In step S8, the powder having the binders adhering thereto
is dried for joining. Here, radiation from the infrared lamp 60 is
carried out from above the thinly extended powder layer. This
allows quick drying of the binders adhering to the powder. Here, in
the case of binders that are quickly hardened by natural drying,
the radiation by the infrared lamp 60 is not particularly needed.
When the drying is completed, the formation of a cross section body
for one layer of the 3D product is completed.
[0085] When the formation of one layer is ended, the procedure goes
to the step S9, where the drive controlling part 12 judges, on the
basis of the number of laminates input in the step S3, whether the
process of lamination for the number of laminates has been
completed or not (i.e. whether the formation of the 3D product has
been completed or not). If the judgement is "NO", the process from
the step S4 is repeated, whereas if the judgement is "YES", the
forming operation is ended. When the formation of the 3D product is
completed, the powder to which the binders have not been applied is
separated to take out the bound body (3D product) of the powder
bound by the binders. Here, the unbound powder may be collected and
used again as the material.
[0086] If the procedure returns to the step S4, an operation is
carried out to form a new powder bound body of the (N+1)-th layer
on the upper side of the N-th layer. By repeating these operations
for the number of laminates, the colored bound bodies are
successively laminated layer by layer on the stage 32, whereby a 3D
product of the 3D original object is finally formed on the product
forming stage 32.
[0087] The 3D product 91 obtained in this manner is shown in FIGS.
6A and 6B. FIG. 6A shows a cross section of the 3D product 91, and
FIG. 6B shows an enlarged representation of the A part in FIG. 6A.
Referring to FIG. 6B, the region 91a near the surface side of the
3D product 91 is colored with a single color or a plurality of
colors by the binder of W, M, C, and W, as illustrated in hatches,
and the region 91b in the inside of the 3D product 91 is formed
with a colored binder of W. In other words, the colored region in
FIG. 6B is formed by selectively jetting the colored binders from
the jetting nozzles 22a to 22d in accordance with the color data,
whereas the inside region, which does not need coloring, is formed
by jetting the white binder from the jetting nozzle 22d for the
purpose of simply joining the powder.
[0088] By using such a coloring mechanism, various coloring is made
possible. For example, among the colored regions in FIG. 6A,
[0089] the region 911 can be colored in thin yellow by a
predetermined arrangement of dots in yellow Y and white W,
[0090] the region 912 can be colored in green by arrangement of
dots in cyan C and yellow Y, and
[0091] the region 913 can be colored in stripes by alternate
arrangement of magenta M sections and white W sections in
bands.
[0092] Further, one 3D product itself may be colored with a single
color (for example, yellow), while another 3D product may be
colored in a different color.
[0093] In other words, in the present invention, capability of
various coloring includes two meanings: increase of the degree of
freedom in coloring for one 3D product, and capability of changing
the color for each of various 3D products.
[0094] Therefore, by adopting a construction such as the 3D product
forming apparatus 100 in this embodiment and selectively imparting
a plurality of colors in accordance with the color information,
various coloring can be performed in the process of forming a 3D
product, and a colored product can be created in a short time and
at a low cost without resorting to manual labor.
[0095] Referring to FIG. 6B, the colored region is not limited to
the surface of the 3D product 91 alone but extends to a little
inside region. Generally, since the regions that need coloring are
limited typically to the surface of the product, it is sufficient
to perform coloring with a colored binder on only the part of the
product appearing on the surface. However, in the case of a product
having a overhung part or an underhung part, the parts that are not
colored appear on the surface of the product unless the inside of
the outermost layer of the cross section bodies of adjacent upper
and lower layers is colored.
[0096] Furthermore, strictly coloring only the surface needs a
highly precise control of the amount of the movement of the nozzle
head 22 and the jetting timing of the binders, so that it is
preferable to ensure an offset of the color information in the
cross section data by a predetermined width to the inside.
Furthermore, by forming a colored region to the inside for a
predetermined amount as illustrated in FIG. 6B, it is possible to
prevent the white color of the binder for the inside from being
exposed even if scratches or the like are generated in the surface
of the 3D product 91.
[0097] The binder for use in joining the powder in the inside
region of the product need not be white, so that a natural binder
(colorless and transparent, milky white) that is not colored may be
used.
[0098] Further, it is preferable that a binder of a specific color
for joining the inside is stored in the tank part 21 in a larger
amount than the binders of the other colors. Also, even the inside
region of the 3D product can be colored in different colors so as
to classify the internal structures. It is effective to color also
the inside region of the 3D product if the 3D product is cut after
forming the product, and the cross-section structures are shown as
a cut model.
[0099] If a system of CAD/CAM/CAE is introduced to the computer 11
in the 3D product forming apparatus 100 in this embodiment, it is
possible to increase the speed in forming the product and quality
improvement of design can be promoted.
[0100] 1-3. Specific Modes of Coloring
[0101] Next, coloring in the process of forming a 3D product in
this embodiment will be described.
[0102] In this embodiment, binders are used for binding the powder
serving as a material for forming the 3D product, and the 3D
product is colored during the process of forming the 3D product by
jetting the colored binders of the four colors of Y, M, C, and W.
In a microscopic view, the particles of the colored binders smaller
than the powder particles adhere to the peripheries of the powder
particles and fill the gap between the powder particles, whereby
the coloring is performed.
[0103] Among the jetting nozzles 22a to 22d, the jetting nozzles
22a to 22c jet the colored binders of the color components of Y, M,
C that can represent different color components by mixing the
fundamental colors, while the jetting nozzle 22d jets the colored
binder of white. A mixed color or a gray scale (density scale) of
colors can be represented as an area gray scale in the 3D product
by an assembly of the dot arrangements of the minute liquid drops
of the binders jetted from the nozzles 22a to 22d.
[0104] Generally, it is sufficient to mix three primary colors of
Y, M, C in order to color the product; however, in order to
represent the depth of color (gray scale), it is effective to jet
and mix a white binder in addition to the binders of the three
primary colors. Since letters and images are printed on a sheet of
white paper with ink, toner, or the like in a general printer or
the like, the white ink is not necessary if the white color of the
paper serving as the base material is utilized, and the depth of
each color component can be represented fundamentally by using the
three colors of Y, M, C. However, in the case where the color of
the powder serving as the material for forming the 3D product is
not white, it is especially effective to use the white binder.
[0105] In other words, although a dark color can be represented by
mixing the color components of Y, M, C, the white color cannot be
represented thereby, so that by preparing a binder of faint color
such as white for binding the powder, and using the white binder
also in coloring the surface, a suitable coloring can be carried
out on the 3D product 91.
[0106] Hereafter, descriptions will be made on an example of a mode
of jetting the colored binders in the case of representing the
depth in coloring the 3D product 91 in this manner.
[0107] FIG. 7 is a view illustrating an example of gray scale
representation for cyan. When the drive controlling part 12
performs a predetermined gray scale conversion, a multi-valued gray
scale data contained in the cross section data is converted into
two-value (binary) data for each fundamental dot region (the
smallest rectangle in FIG. 7). The fundamental dot region is the
smallest unit to which a selected one of the four kinds of the
colored binders is applied, and the two-value data serves as
information for controlling ON/OFF of each of the jetting nozzles
22a to 22d.
[0108] FIG. 7 illustrates a fundamental assembly region by a
2.times.2 matrix arrangement of fundamental dot regions. By
changing the jetting pattern of the binders of color components to
the fundamental dot region for coloring, gray scale representation
or mixed color representation is made possible. In the case of
representing a faint cyan, cyan is jetted to one fundamental dot
region in the 2.times.2 matrix arrangement, and white is jetted to
the other fundamental dot regions. Further, in the case of
representing a deep cyan, cyan is jetted to the whole of the
fundamental assembly region. Thus, by changing the jetting ratio of
the cyan binder and the white binder to the fundamental assembly
region, the gray scale change from faint cyan to deep cyan can be
suitably represented.
[0109] In the example of FIG. 7, for the sake of explanation, the
fundamental assembly region for coloring generated by gray scale
conversion is constructed with four fundamental dot regions;
however, it is not limited thereto. For example, if the cross
section data has 256 gray scales and is to be converted into
2-value (binary) data for controlling ON/OFF without decreasing the
gray scale, the fundamental assembly region is constructed with an
assembly of 256 fundamental dot regions.
[0110] Next, FIG. 8 is a view showing an example of representation
in which the color changes from faint cyan to faint yellow. The
left end of FIG. 8 is a jetting pattern of C and W in representing
faint cyan, and the right end is a jetting pattern of Y and W in
representing faint yellow. In changing the color from faint cyan to
faint yellow through a mixed color of cyan and yellow, such a color
change can be represented by gradually changing the ratio of
jetting C, Y, and W into the fundamental assembly region, as shown
in FIG. 8.
[0111] Even in such a case, as already described, the colored
binders of C, Y, and W are preferably jetted in the same amount per
unit area in order to ensure the strength of the 3D product.
[0112] FIGS. 9A and 9B show that a plurality of the aforesaid
fundamental assembly regions for coloring are assembled. FIG. 9A
shows a jetting pattern of C and W, and FIG. 9B specifically shows
a coloring mode represented by the jetting pattern of FIG. 9A. As
shown in FIGS. 9A and 9B, the 3D product 91 can be colored in the
product forming process by the drive controlling part 12
controlling the jetting pattern.
[0113] Thus, in this embodiment, the colored binders of Y, M, C,
and W are used for joining and coloring in forming a colored part
of the 3D product 91, and the white binder is used for joining the
inside in forming the inside of the 3D product 91, whereby the
coloring can be made in accordance with the 3D original object
during the product forming process.
[0114] Here, the colored binders jetted from the jetting nozzles
22a to 22c may be respectively colored with other color components
(for example, R (red), G (green), B (blue), and others); however,
by using and mixing the binders colored in the three primary colors
of Y, M, and C, it produces an effect that the 3D product 91 can be
colored in all the color components such as intermediate
colors.
[0115] Further, the binder jetted from the jetting nozzle 22d that
functions only for joining the powder is not limited to white
alone, and may be a binder having a cream color or the like.
However, a white binder is preferably used for joining in order to
vividly represent the white color or gray scale of the 3D original
object in the 3D product 91.
[0116] Furthermore, if black is to be represented on the surface
side of the 3D product 91, the black color can be represented by
jetting the three primary colors of Y, M, and C; however, in order
to reproduce vivid black color, a nozzle for jetting a binder
colored in black may be separately provided.
[0117] Also, binders of two or more colors may be jetted
simultaneously from the jetting nozzles, or alternatively binders
of different colors may be jetted with a time interval.
[0118] In this embodiment, the powder serving as a material of the
3D product is a white powder. In the case of printers, images are
printed on white paper sheets, so that colored inks are applied
only on portions to be colored, and gray scale representation of
color is made by a balance with the underlying white color. In the
same manner, in this embodiment, color generation can be improved
by using white powder as the underlying powder.
[0119] If the powder material has a ground color instead of being
colorless and transparent, it is sufficient that the colorless and
transparent binder is applied to a region which is to have the same
color as the ground color of the powder material. Further, if the
color corresponding to the ground color of the powder material is
to be thinned, the colorless and transparent binders and the white
binders may be arranged in dots at a predetermined ratio. For this
reason, if a colorless and transparent binder is included in a
plurality of binders, it is preferable to prepare a binder having a
color different from the ground color rather than preparing a
binder of the same color as the ground color, whereby the width of
color representation is all the more widened.
[0120] 1-4. Specific Embodiment of White Powder Material
[0121] Next, a specific example of the powder material in the case
of white powder will be described. As already described, the white
powder for use may be starch powder, gypsum powder, or the like.
However, in order to more suitably realize the color representation
of the colored 3D product, it is preferable to produce the white
powder with the use of a white pigment. In other words, by
performing coloring with YMCK (black) on a white powder that uses a
white pigment, the color of the 3D product can be made more vivid
and a suitable multi-gray-scale representation can be realized. If
a white powder is used, a colorless and transparent binder is
imparted to the white portion of the 3D product.
[0122] As the powder that uses a white pigment, powder made from
white pigment itself, mixture of starch powder or gypsum powder
with white pigment, resin powder such as polyethylene containing
white pigment, and others can be utilized.
[0123] If a white pigment is to be mixed with a principal
product-forming material powder (main product-forming particles)
such as starch powder or gypsum powder, the particle size of the
white pigment is preferably smaller than the particle size of the
3D product forming material powder. This allows the surface of the
3D product forming material powder to be covered with the fine
particles of the white pigment when these two are mixed, thereby
improving the color generation of white in the powder material. As
a result, color reproducibility and gray scale reproducibility of
the 3D product are improved.
[0124] Further, in the case of allowing white pigment to be
contained in resin powder, a suitable white powder material can be
obtained by dispersing white pigment in a hot-melted resin for
mixing in the process of producing the resin powder (white pigment
may be kneaded therein) to make the resin colored in white,
followed by forming it into powder. On the other hand, if a
thermoplastic resin powder is to be used as a principal 3D product
forming material powder, only the surface of the resin powder can
be suitably turned into white by allowing the white pigment to be
adsorbed around the powder particles in a state in which the resin
powder is heated and softened.
[0125] Specific examples of white pigment for use include basic
lead carbonate (2PbCO.sub.3Pb(OH).sub.2, so-called silver white),
zinc oxide (ZnO, so-called zinc white), titanium oxide (TiO.sub.2,
so-called titanium white), strontium titanate (SrTiO.sub.3,
so-called titanium strontium white), and others.
[0126] Here, as compared with other white pigments, titanium oxide
has a smaller specific weight, has a larger refractive index, and
is more stable both chemically and physically, so that it has a
larger hiding power and coloring power as a pigment, and is
excellent in the durability against acid, alkali, and other
environments. Therefore, it is preferable to use titanium oxide as
the white pigment. Needless to say, other white pigments may be
used in accordance with the type of the powder material and the
binder components (those other than the enumerated white pigments
may be used).
[0127] 1-5. Other Examples of Powder Material
[0128] As another example of the powder material described above, a
biodegradable resin powder may be used. By utilizing the
biodegradable resin powder, the 3D product can be decomposed into
water, carbon dioxide, and others owing to microorganisms in nature
by burying the product in earth after the fabricated 3D product
becomes unnecessary. As a result, wastes can be suitably
discarded.
[0129] The biodegradable resins are classified into "those
utilizing natural substances", "those produced by microorganisms",
and "those chemically synthesized".
[0130] Those utilizing natural substances are, for example, mixture
of natural polymer such as cellulose or starch with plastics,
chemically modified natural polymers, and others. For example,
"EVACORN" manufactured by Nippon Corn Starch Co., Ltd., "MATABY"
manufactured by Novamont Co., Ltd. in Italy, and others may be
mentioned.
[0131] Biodegradable resins produced by microorganisms are produced
by utilizing a property of microorganisms that store aliphatic
polyesters in the cells thereof. For example, "BIOPOLE"
manufactured by Monsanto Co., Ltd. in the United States, "BIOGREEN"
manufactured by Mitsubishi Gas Chemical Co., Ltd., and others may
be mentioned.
[0132] Those chemically synthesized are, for example,
polycaprolactone, polylactic acid, polyvinyl alcohol, and others,
and are produced by polymerization reaction or fermentation method.
For example, "REISIA" manufactured by Mitsui Chemical Co., Ltd.,
"CELLGREEN" manufactured by Daicel Chemical Industry Co., Ltd.,
"ECOPLAY" manufactured by Cargill Co., Ltd. in the United States,
and others may be mentioned.
[0133] Here, if biodegradable plastics are to be utilized, they
have good compatibility with various adhesives such as produced
from vinyl acetate, urea, acryl, or urethane, because their main
source materials are natural materials such as starch or cellulose,
so that they can improve the fixation strength of the 3D
product.
[0134] 2. Second Preferred Embodiment
[0135] 2-1. Construction of essential parts of the 3D product
forming apparatus
[0136] The construction of the 3D product forming apparatus of the
second embodiment is similar to the 3D product forming apparatus
100 of the first embodiment; however, each tank is provided with a
sensor for sensing the amount of the remaining colored binder.
[0137] FIG. 10 is a schematic view of a 3D product forming
apparatus 100A according to the second embodiment of the present
invention. In the 3D product forming apparatus 100A of the second
embodiment, a cable 26 is provided for transmitting a signal from
the sensors of the tank part 21A to the drive controlling part
12.
[0138] FIG. 11 is a view showing a partial cross section of the
tank part 21A. Sensors 25a to 25d corresponding to the tanks 21Aa
to 21Ad are disposed at a lower portion of the tank part 21A. The
sensors 25a to 25d sense the amounts of the remaining binders in
the tanks 21Aa to 21Ad. The sensors 25a to 25d calculate the
remaining amounts by sensing the head pressure of the binders
accommodated in the tanks 21Aa to 21Ad (the pressure generated at
the lower portion of the tank in correspondence with the amount of
the binder). Here, as the sensors, one or a plurality of level
switches may be vertically disposed in each of the tanks 21Aa to
21Ad. In this case, the construction thereof can be comparatively
simplified as compared with the above-mentioned system of sensing
the head pressure, although the amount of the remaining binder
cannot be sensed continuously.
[0139] 2-2. Operation of the 3D Product Forming Apparatus
[0140] FIG. 12 is a flowchart for describing the overall operation
of the 3D product forming apparatus 100A. This flowchart is similar
to the flowchart shown in FIG. 2; however, operations pertaining to
the above-mentioned sensing and control of the amount of the
remaining binders are mainly added. Hereafter, the operations
different from the flowchart shown in FIG. 2 will be described.
Here, the steps S11 to S13, S16 to S18, S20, and S22 correspond to
steps S1 to S3, S4 to S6, S8, and S9 of FIG. 2, respectively.
[0141] In step S12, a cross section data for each cross section
obtained by slicing the 3D original object is prepared from the
model data in the same manner as in step S2 of FIG. 2. The data are
decomposed to the region to be colored, which appears on the
surface of the 3D product and hence needs coloring, and the region
that does not need coloring, which corresponds to the inside of the
3D product.
[0142] In step S14, a joining binder used only for joining the
powder is selected from the four colored binders for the region of
the 3D product that does not need coloring. In this case, a
specific color, for example, a white binder, may be selected as a
default.
[0143] Also, the number of powder layers is set as the interval for
sensing the amount of the remaining binders in the tanks 21Aa to
21Ad. Since the thickness of one powder layer is small, there will
not be a conspicuous difference in the amount of the consumed
binders for one powder layer. Therefore, the sensing is facilitated
by making the amounts of the remaining binders definite from the
accumulated consumption of the binders for n powder layers.
[0144] In step S15, 0 (zero) is set as an initial value for
counting the number of deposited powder layers that are
successively formed on the product forming stage 32.
[0145] In steps S19a and S19b, which correspond to the step S7 of
FIG. 2, different binders are used for the region to be colored
(coloring region) and the region that does not need coloring
(non-coloring region) in the cross section data prepared in the
step S12. In other words, each colored binder is jetted to the
powder layer for the region to be colored, whereas only the
selected joining binder is jetted to the region that does not need
coloring.
[0146] In step S21, the number i of the deposited layers is
incremented by one because one layer of the powder bound body has
been formed by drying the binder in step S20.
[0147] In step S22, if the formation of the 3D product is not
completed yet, the procedure goes to the step S23.
[0148] In step S23, the drive controlling part 12 judges whether
the remainder of the number i of deposited layers as divided by n
is zero or not (i.e. whether the number i of the deposited layers
is a multiple of n or not). If the remainder is zero, the procedure
goes to step S24, whereas if the remainder is not zero, the
procedure goes to step S16.
[0149] In step S24, the sensors 25a to 25d sense the amounts of the
remaining binders in the tanks 21Aa to 21Ad. Then, the binder that
is remaining in the largest amount, i.e. the binder that has been
least frequently used, is selected as the next binder for joining.
For example, in the case shown in FIG. 11, the binder in the tank
21Ab is selected as the next binder for joining because the tank
21Ab accommodates the largest remaining amount of the binder.
[0150] Here, the sensors 25a to 25d may issue an alarm to the
operator to prompt the replenishment of the tanks 21Aa to 21Ad with
the binders if the amount of the remaining binders becomes
small.
[0151] Through the operations described above, the colored binder
that is least frequently used can be preferentially used for
joining the inside region that is not related to coloring, whereby
the amount of consumption of the colored binders can be made
uniform. This makes it possible to effectively utilize the colored
binders, and can extend the time interval for replenishing the
tanks 21Aa to 21d with the binders.
[0152] Further, in the case where only one level switch is disposed
in each of the tanks 21Aa to 21Ad, the most preferential binder in
a predetermined preferential order (for example, the order of WYMC)
can be selected as a binder for joining among the binders that
remain in an amount above a predetermined standard level.
[0153] In any case, the binder that is remaining in a comparatively
large amount is used as the next binder for joining.
[0154] 3. Third Preferred Embodiment
[0155] 3-1. Construction of Essential Part of the 3D Product
Forming Apparatus
[0156] The construction of the 3D product forming apparatus of the
third embodiment is similar to the 3D product forming apparatus 100
of the first embodiment, except that two blades are provided.
[0157] FIG. 13 is a schematic view showing a 3D product forming
apparatus 100B according to the third embodiment. Two blades 51Ba
and 51Bb are disposed on both sides of the XY-direction moving part
23B. The left blade 51Ba and the right blade 51Bb are
mirror-symmetric with respect to the YZ-plane.
[0158] The driving part 24B for driving the XY-direction moving
part 23B serves to drive the above-mentioned two blades
independently in the up-and-down direction (Z-direction). On the
basis of instructions from the drive controlling part 12, the
movement of the nozzle head 22 in the XY-plane and the ascending
and descending movement of the blades 51Ba and 51Bb in the
up-and-down direction are made possible. Here, with respect to the
movement of the XY-direction moving part 23B, the right direction
of the paper sheet (the direction of increasing X) is referred to
as the forward direction, and the left direction of the paper sheet
(the direction of decreasing X) is referred to as the backward
direction.
[0159] Further, the 3D product forming apparatus 100B includes two
powder supplying parts 40Ba and 40Bb. In accordance therewith, the
upper work area of the product forming main body 31B is extended as
compared with the 3D product forming apparatus 100 of the first
embodiment in order to ensure the provisional powder placing parts
31Ba and 31Bb for depositing the powder from the powder supplying
parts 40Ba and 40Bb.
[0160] 3-2. Operation of the 3D Product Forming Apparatus
[0161] FIG. 14 is a flowchart for describing an overall operation
of the 3D product forming apparatus 100B. This flowchart is similar
to the flowchart shown in FIG. 2; however, operations pertaining to
the above-mentioned two kinds of blades 51Ba and 51Bb are mainly
added. Hereafter, the operations different from the flowchart shown
in FIG. 2 will be described. Here, the steps S31 to S34, S38, and
S39 correspond to steps S1 to S4, S8, and S9 of FIG. 2,
respectively.
[0162] In step S35, it judges whether the layer to be deposited
next is an odd-numbered layer or not (i.e. whether the number of
deposited powder layers will be odd or not). Here, if the number is
odd, the procedure goes to the step S36a, whereas if the number is
even, the procedure goes to the step S36b. The overall operation of
the 3D product forming apparatus 100B in the subsequent steps will
be described with reference to FIGS. 15A to 15D.
[0163] In step S36a, the powder is supplied from the powder
supplying part 40Ba on the starting point side in the forward
direction, i.e. on the left side, as shown in FIG. 15A, thereby to
form a heap Ma of the powder material on the left side.
[0164] In step S37a, the colored binder is jetted by the nozzle
head while forming a thin powder layer in the forward direction.
Here, first, the XY-direction moving part 23Ba is moved to the
starting point of the forward direction, and the lower tip end of
the right blade 51Bb is lowered to be in contact with the uppermost
surface 31Bc of the provisional powder placing part 31Ba. Then, as
shown in FIG. 15B, the XY-moving part 23Ba is moved in the forward
direction to spread the heap Ma of the powder with the right blade
51Bb, thereby to form a powder layer. Further, the binders are
jetted from the nozzle head 22 located behind the right blade 51Bb
in the moving direction. During these operations, the left blade
51Ba is in an upward, stand-by position, thereby to prevent the
left blade 51Ba from disturbing the surface of the powder layer
after being applied the binders.
[0165] On the other hand, in step S36b, the powder is supplied from
the powder supplying part 40Bb on the starting point side in the
backward direction, i.e. on the right side, as shown in FIG. 15C,
thereby to form a heap Mb of the powder material on the right
side.
[0166] In step S37b, the colored binder is jetted by the nozzle
head while forming a thin powder layer in the backward direction.
Here, first, the XY-direction moving part 23Ba is moved to the
starting point of the backward direction, and the lower tip end of
the left blade 51Ba is lowered to be in contact with the uppermost
surface 31Bc of the provisional powder placing part 31Bb. Then, as
shown in FIG. 15D, the XY-moving part 23Ba is moved in the backward
direction to spread the heap Mb of the powder with the left blade
51Ba, thereby to form a powder layer. Further, the binders are
jetted from the nozzle head 22 located behind the left blade 51Ba
in the moving direction. During these operations, the right blade
51Bb is in an upward, stand-by position, thereby to prevent the
right blade 51Bb from disturbing the surface of the powder layer
after the binders are applied thereto.
[0167] By the operations described above, the reciprocal movement
of the nozzle head 22 and the blades 51Ba and 51Bb in the
X-direction can be utilized without loss, whereby the time for
returning the blade and the time for returning the nozzle head will
be unnecessary. This can shorten the time for forming a thin powder
layer and the time for applying the binders to the powder layer. As
a result, the 3D product can be formed more quickly. Moreover,
since the blades 51Ba and 51Bb on both sides are ascended and
descended in a complementary manner, disturbance of the product
with the blade can be especially effectively prevented.
[0168] 4. Fourth Preferred Embodiment
[0169] FIG. 16 is a view showing a construction of a 3D product
forming apparatus 100C according to the fourth embodiment of the
present invention. In the 3D product forming apparatus 100C
according to the fourth embodiment, the ink and the binders are
jetted separately, and the construction is different from the one
shown in FIG. 1, the only difference lying in that the moving part
main body 23a includes a nozzle head 221 for ink and a nozzle head
222 for binders, and the tank part 21 includes a tank 211 for ink
and a tank 212 for binders. Here, in FIG. 16, only the principal
constructions are denoted with reference numerals similar to those
of the first embodiment.
[0170] The tank 211 and the nozzle head 221 for ink are separated
for each color of the ink (for example, each color of CMYK). The
ink corresponding to the black color (K) is used in the case where
one wishes to vividly generate the black color, and if the powder
material is not in vivid white, ink of white color (W) may be
further used.
[0171] The operation of the 3D product forming apparatus 100C
according to the fourth embodiment is basically the same as that of
the first embodiment, and is similar to the flow of the operations
in FIG. 2. However, the operation of step S7 is different in that
the ink and the binders are jetted separately. FIG. 17 is a
flowchart showing the flow of operations of the step S7 in the
fourth embodiment.
[0172] When one thin powder layer is formed (FIG. 2: steps S4 to
S6), first, the ink is jetted from the nozzle head 221 for ink in
accordance with the color data generated in the step S2 (step S71).
The jetting of the ink is carried out selectively in accordance
with the color to be imparted in the same manner as the jetting of
the colored binders in the first embodiment. Subsequently, a
colorless and transparent binder is jetted from the nozzle head 222
for binders in accordance with the configuration data (step
S72).
[0173] By these operations, ink is applied to the region to be
colored of each layer exemplified in FIG. 6A, and a colorless and
transparent binder is applied to the region to be colored and the
region that does not need coloring, i.e. the region corresponding
to one cross section of the 3D product. Here, after the ink is
applied, the binders are applied by jetting the ink and the binders
in parallel while moving the moving part main body 23a to the right
side (the nozzle head 221 side) in FIG. 16.
[0174] Thereafter, the binders are dried (FIG. 2: step S8), thereby
to complete the formation of the powder bound body 81 in one powder
layer in the same manner as in the first embodiment.
[0175] Then, by repeating the steps S4 to S8, the 3D product is
created in the space WK where the formation of 3D products is
carried out (step S9).
[0176] In the 3D product forming apparatus 100C, the ink is jetted
before the binders are jetted. This is due to two reasons. One
reason is to prevent blurring of the ink caused by jetting the ink
immediately after the binders are jetted. Generally, the period of
time required from jetting ink until the ink is dried and stably
fixed is shorter than the period of time required from jetting the
binders until the binders are dried (or hardened) and brought into
a stable state. For example, a fast-drying ink is provided in many
cases as an ink for printers of ink jet type that print on a paper
sheet.
[0177] For this reason, if the ink is jetted immediately after the
binders are jetted, the ink is imparted onto the binders before the
binders are stabilized, thereby blurring and mixing the colors. As
a result, the reproducibility or the resolution of colors is
deteriorated, thereby failing to provide a 3D product in a desired
colored state. Further, by mixing of the binders with ink, the area
where the powders are bound with each other will be widened,
thereby deteriorating the configuration precision.
[0178] Needless to say, one can consider a system in which the ink
is jetted after waiting for a while till the binders are dried or
hardened. In this case, however, the period of time required in
forming a powder bound body for one layer will be long. Referring
to FIG. 16, in the case where the nozzle head 221 for ink and the
nozzle head 222 for binders are fixed to the moving part main body
23a, the ink and the binders can be successively applied to the
powder layer by simultaneously jetting the ink and the binders
while moving the moving part main body 23a to the right side
(nozzle head 221 side) shown in FIG. 16. In other words, applying
the ink and the binders is completed simply by passing the moving
part main body 23a only once over an arbitrary region on the powder
layer.
[0179] However, if the binders are to be applied to the powder
layer before the ink, the ink must be applied after the binders are
applied to the powder layer once and then the binders are dried and
hardened. In this case, the moving part main body 23a must be
passed twice over an arbitrary region on the powder layer. As a
result, the period of time required in forming a powder bound body
for one layer will be long. Here, even if the nozzle head 221 for
ink and the nozzle head 222 for binders are independently movable,
the ink and the binders can be applied while simultaneously moving
the two nozzle heads 221 and 222 by jetting the ink first, whereby
the 3D product can be formed more quickly than in the case of
jetting the binders first.
[0180] Also, even in the case of individually jetting different
inks, the inks can be quickly applied while preventing the blurring
of the colors by jetting a quick-drying ink first and then jetting
the non-quick-drying ink later, in the same manner as in the
above-mentioned relationship of the ink and the binders.
[0181] Thus, a suitably colored (or suitably configured) 3D product
can be created quickly by applying a material that requires a
shorter period of time for stabilization after application (i.e.
material that is more quickly dried or hardened) first in applying
plural kinds of materials (plural kinds of inks or plural kinds of
binders) to a powder layer.
[0182] The other reason for applying the ink first and then
applying the binders later is that, if the binders are applied
first and the ink is applied after the binders are stabilized, the
ink does not penetrate into the powder layer, thereby making it
difficult to perform suitable coloring. In this case, the ink
adheres only to the surface of the stabilized binders and the
inside of the powder layer is not colored. As a result, when the
completed 3D product is cut, the coloring in the cross section will
be unsuitable. Here, the jetting of the binder is not limited to
the mode in which the binder is jetted from one nozzle to one
region on the powder layer, but may be a mode in which the binders
are constructed with plural kinds of materials and the materials
constituting the binders are jetted from plural nozzles to one
region on the powder layer, as in the case of a two-liquid type
adhesive of an epoxy system or an adhesive imparted with a
hardening promoting agent.
[0183] As described above, in the 3D product forming apparatus 100C
according to the fourth embodiment, a 3D product in which the color
and the configuration thereof are suitably reproduced can be formed
quickly by applying the ink, which is a material that requires a
shorter period of time for stabilization after being applied to the
powder layer, before the binders are applied.
[0184] 5. Fifth Preferred Embodiment
[0185] In the above-mentioned embodiments, a material having a
different color is supplied from each nozzle. However, it is
possible to adopt a construction in which plural kinds of materials
(binding agents) that each provide a different sense of mass
(including feel of surface and hardness) of the product are jetted
from the respective nozzles irrespective of the colors.
[0186] Among these, examples of a plurality of binding agents
having different senses of mass are:
[0187] (1) a combination of a binder having a luster and a binder
having no luster,
[0188] (2) a combination of a binder visually having a particulate
property and a binder that is visually smooth,
[0189] (3) a combination of a binder comparatively having
transparency and a non-transparent binder,
[0190] (4) a combination of a binder being imparted with a metal
luster and a binder having no metal luster,
[0191] and composite combinations thereof.
[0192] Further, with respect to hardness, an elastic material may
be used as well instead of simply using plural kinds of materials
having different hardnesses. This makes it possible to integrally
form a 3D product partially having elasticity by using a binder
having elasticity on the gripping part in creating a proto-product
of a product having a rubber attached to the gripping part thereof,
with a 3D product forming apparatus.
[0193] As described above, a more complex product can be suitably
fabricated by applying plural kinds of materials that affect not
only the color but also the sense of mass, to the powder layer.
[0194] 6. Sixth Preferred Embodiment
[0195] Next, a case in which a thermoplastic material is used as
the powder material for forming a 3D product will be described.
Here, utilization of a thermoplastic material is possible in any of
the aforementioned embodiments 1 to 5, and a 3D product formed with
a thermoplastic powder material can be produced by repeating the
steps of forming a powder layer and applying the binders. Further,
in the following descriptions, the descriptions will be made by
suitably attaching reference numerals used in the previous
embodiments.
[0196] If a thermoplastic powder material is used, the powder
particles can be bonded to each other to improve the strength of
the 3D product by heating the 3D product that has completed the
formation.
[0197] FIG. 18 is a flowchart that shows a flow of post-processes
after the formation (for example, after the forming operations
shown in FIGS. 2, 12, and 14 are carried out) in the case of
utilizing a thermoplastic powder material. When the bonding of the
powder layers with the binders is completed up to the final powder
layer, the 3D product is left to stand until the strength of the
binders is enhanced to such a degree that the 3D product can be
taken out. When the strength of the binders is sufficiently
enhanced, the 3D product is taken out by the operator from the
powder in the space WK where the formation of 3D products is
carried out, and the unnecessary powder adhering around the 3D
product is removed (step S101). At this time, the powder adhering
to the surroundings or intricate portions of the 3D product is
removed by giving vibration or giving high speed air stream to the
3D product.
[0198] Subsequently, the 3D product is transported to a fixing
apparatus, where the 3D product is heated above the temperature at
which the thermoplastic material is softened, thereby fixing the
powder (this refers to a process of enhancing the binding strength
of the powders with each other) (steps S102, S103). Through this
process, the strength of the 3D product can be easily improved.
[0199] FIG. 19 is a view showing a construction of a fixing
apparatus 71. The inside of the fixing apparatus 71 shown in FIG.
19 is a space where a heating treatment is carried out, and is
equipped with a lamp 711 for radiating a flash light to the 3D
product 91 transported into the fixing apparatus 71. As the lamp
711, a lamp emitting light that can be easily transformed into heat
energy, such as an infrared lamp, a xenon lamp, or a halogen lamp,
is used.
[0200] When the light from the lamp 711 is radiated to the 3D
product 91, the thermoplastic powder material absorbs light energy
on the surface of the 3D product 91, whereby the temperature rises.
As a result, the powders are bound (or welded) with each other on
the surface of the 3D product 91. Thereafter, the lamp 711 is
deenergized (turned off) to harden and bind the powder firmly on
the surface, thereby improving the strength of the 3D product 91.
If a lamp is used for heating the 3D product 91, fixation of the 3D
product 91 can be easily carried out simply by controlling the
energization of the lamp.
[0201] FIG. 20 is a view showing another construction of a fixing
apparatus 71. The inside of the fixing apparatus 71 shown in FIG.
20 is a space where a heating treatment is carried out, and the
inside space is equipped with a heater 721 and a fan 723. Electric
power is supplied to the heater 721 by a power source 722. In other
words, the fixing apparatus 71 is a so-called oven, where the 3D
product 91 is heated by heating air in the inside space. Also, in
the case of the fixing apparatus 71 shown in FIG. 20, the heating
is controlled so as to allow the powders on the surface of the 3D
product 91 to be bound (or welded) with each other, and thereafter
the heating is stopped (or cooling is carried out) to harden the
thermoplastic resin, whereby the strength of the 3D product 91 is
enhanced. Here, in performing the heating treatment, pressurization
may also be carried out.
[0202] FIG. 21 is a view exemplifying a manner in which the
construction of automatically performing the fixation of the 3D
product is added to the 3D product forming apparatus according to
the first embodiment. Here, in FIG. 21, since the upper part of the
3D product forming apparatus 100D is similar to that of the first
embodiment, illustration thereof is suitably omitted.
[0203] In the 3D product forming apparatus 100D, a fixing part 70
is disposed on a lateral side of the product forming part 30, and a
part of the side wall of the product forming part main body 31
(tubular portion) is made into a movable side wall 311. The movable
side wall 311 is connected to a cylinder via a shaft 312, and is
movable in the horizontal direction by driving the cylinder.
Further, a porous plate 321 such as a metal net is disposed on the
product forming stage 32.
[0204] The inside of the fixing part 70 is equipped with a lamp 731
for radiating a flash light to the 3D product and a fan 732 for
removing the unnecessary powder adhering to the 3D product. A guide
roller 733 for guiding the 3D product is disposed at a lower part
of the inside of the fixing part 70, and the guide roller 733 is
linked to a guide roller 734 on the outside of the fixing part
70.
[0205] When the whole of the 3D product 91 is formed in the same
manner as in the first embodiment in the space WK where 3D products
are formed, the product forming stage 32 descends from the state
shown in FIG. 21 by a supporting rod 33a as shown in FIG. 22, and
the 3D product 91 stops at a position where it is surrounded by the
moving side walls 311. Then, the moving side walls 311 are pushed
by the shaft 312 as shown in FIG. 23 to move to the fixing part 70.
This allows the 3D product 91 and the surrounding powder to be
transported to the inside of the fixing part 70 together with the
porous plate 321 while being guided by the guide roller 733.
[0206] When the 3D product 91 and the surrounding powder are
transported to the fixing part 70, the surrounding powder drops
downward from the pores of the porous plate 321. Further, the fan
732 removes the powder adhering to the 3D product 91. Here, in
order to suitably remove the unnecessary powder, the guide roller
733 and the moving side walls 311 may be vibrated.
[0207] When the removal of the unnecessary powder is completed, the
lamp 731 is energized and controlled to fix the thermoplastic
powder constituting the surface of the 3D product as described
before. In other words, after the powder is softened and bound, the
powder is cooled and hardened. This enhances the strength of the 3D
product. After the fixing step is completed, the movable side walls
311 move further as shown in FIG. 24, whereby the 3D product 91 is
transported onto the guide roller 734 together with the porous
plate 321.
[0208] When the completed 3D product 91 is taken out from the
movable side walls 311, the movable side walls 311 return to the
product forming part 30 together with the porous plate 321, and the
procedure returns to the first stage of creating a 3D product.
[0209] Here, the fixing part 70 may be an oven type shown in FIG.
20, and the product forming part 30 and the fixing part 70 may be
separate. If the 3D product 91 is to be transported automatically
from the product forming part 30 to the fixing part 70, any other
mechanism may be adopted. Further, the technique of forming a 3D
product with the use of a thermoplastic powder material and
enhancing the strength of the 3D product by heating can be utilized
in any mode in which 3D products are formed with powder.
[0210] Next, the thermoplastic material to be used as the powder
material will be described. As the thermoplastic material, a resin
(such as thermoplastic plastic or thermoplastic rubber) or a metal
is adopted. Needless to say, other materials may be used if they
have thermoplasticity. Here, the color generation of the 3D product
can be improved by using a white powder, and the color of the
powder can be prevented from being an obstacle to coloring by using
a colorless and transparent powder. In other words, by using a
white powder or a colorless and transparent powder, a suitable
color reproduction can be realized. This applies to the first to
fourth embodiments as well.
[0211] As the thermoplastic resin, there are many kinds such as
polyolefin, polystyrene, ABS, polyvinyl chloride, methacrylic
resin, polyacrylate, acrylic rubber, polyester-based thermoplastic
elastomer, polyurethane elastomer, styrene-based thermoplastic
elastomer, isoprene-based thermoplastic elastomer, olefin-based
thermoplastic elastomer, polycarbonate, polyester, and polyimide.
Also, by utilizing thermoplastic rubbers or elastomers, a 3D
product having elasticity can be produced.
[0212] As the thermoplastic metal, a low-melting-point solder, a
U-alloy (Bi--Pb--Sn--Cd--In alloy), and others can be used.
[0213] Here, in the case of utilizing a thermoplastic resin, the
powder can be easily turned into white, and also a suitable
coloring can be easily carried out.
[0214] Here, a general-purpose toner for electrophotography such as
used in a copier or a printer of electronic printing type can be
utilized as the thermoplastic material. The toner for electronic
printing (hereafter referred to as "toner") contains a
thermoplastic resin as a major component, is easily available, and
has a uniform particle size, so that the toner is a suitable
material for forming a 3D product with powder.
[0215] The toner is constructed mainly with a resin, an internal
additive added to the inside of the particles, and an external
additive added to the outside of the particles. Generally, the
resin occupying 95% as a component of the toner, is polyester or
styrene acryl. Further, an organic metal compound as an internal
additive of the resin powder, a pigment such as carbon, an organic
metal compound as an electric charge controlling agent, and wax
such as polyethylene, polypropylene, and natural wax as a lubricant
are dispersed in several percents in the resin powder. Further,
silicon oxide, titanium oxide, strontium oxide, calcium stearate,
or the like is fixed in several percents on the surface of the
particles as an external additive.
[0216] Further, the adhesive to be contained in the binders in the
case of using a toner may be, for example, a polyester-based
adhesive, an acrylic-resin-based adhesive, a cyanoacrylate-based
adhesive, and others, and can be jetted in an ink jet type if it is
an adhesive of an aqueous emulsion type. As the technique for
fixing the toner, the above-mentioned flash system (lamp system) or
an oven system can be utilized.
[0217] As described above, by using toner as a powder material, the
thermoplastic powder is available easily and at a low cost.
[0218] 7. Modified Examples
[0219] For coloring, three primary colors of light consisting of R
(red), G (green), and B (blue) may be used.
[0220] For colored binders, it is not essential that the binders
are provided in four kinds of colors, and they may be provided in
five kinds of colors consisting of three primary colors, a white
color, and a colorless and transparent color, or may be provided in
six kinds of colors.
[0221] For a jetting nozzle, it is possible to adopt a construction
in which the binders of different colors accommodated in the tanks
are mixed before being jetted and are then jetted.
[0222] For the color of the powder, it is not essential that the
powder is white, and may be colored in blue or yellow, or may be
colorless and transparent such as in glass powder.
[0223] For formation of the powder layer, it is not essential to
use a blade, and it is possible to use a roller or the like.
[0224] In the third embodiment, the blades on both sides are
represented as "right and left"; however, the relationship is
relative, and even in the case of an apparatus in which the blade
and others are moved in the forward and backward directions to
spread the powder, the moving direction is the left-and-right
direction when the apparatus is turned by 90.degree.. Therefore,
without loss of generality, the moving direction can be called
"right-and-left" direction.
[0225] In the third embodiment, the blade on the side of forming a
powder layer is lowered and the other blade is raised in forming
the powder layer effectively by using two blades; however, the
other blade need not be raised if a condition is satisfied such
that the other blade does not affect the powder layer because of
the property of the powder material or the property of the binder
material.
[0226] In the aforesaid embodiments, the nozzle head is allowed to
scan only the region where the configuration data exist; however,
it is possible to adopt a construction in which the movement of the
nozzle head performs raster scan of the whole work area of the
product forming part main body. In this case, the configuration
data is not necessary, and a construction is adopted such that only
the coloring data is prepared as the cross section data (i.e. the
coloring data serves as the configuration data as well).
[0227] In the aforesaid first to third embodiments, each color is
allowed to have a binder function; however, one (preferably white)
of the plurality of colors may be provided in a binder, and the
other colors may be provided in ink that does not have a binder
function. In other words, it is sufficient that at least one kind
of a binder (a binding agent or a material that contains a binding
agent) applied to the powder layer exists, and the fourth
embodiment is an example in which one kind of a colorless and
transparent binder is used.
[0228] While the invention has been shown and described in detail,
the foregoing description is in all aspects illustrative and not
restrictive. It is therefore understood that numerous other
modifications and variations can be devised without departing from
the scope of the invention.
* * * * *