JP6724974B2 - Sinter modeling method, liquid binder, and sinter model - Google Patents

Description

The present invention relates to a sintering modeling method, a liquid binder used in sintering modeling, and a sintering model.

One of the modeling methods for forming a three-dimensional solid model (model) is a layered modeling method. Examples of the layered modeling method include an optical modeling method in which a photocurable resin is laminated and selectively cured by a laser to form each layer of a cross section of a modeled object, and a powder material is laminated and selectively welded and solidified by a laser. Powder sintering method to form each layer, melt material deposition method to form each layer by heating and extruding a thermoplastic material from a nozzle and depositing, sheet material such as paper cut into a model cross-sectional shape and laminated A sheet stacking method of forming by bonding is proposed.

Patent Document 1 discloses the following three-dimensional printing technology (method for manufacturing a three-dimensional structure).
First, a powder material containing ceramic, metal, etc. is deposited in layers. A binder material that binds the powder materials together is then applied to selected areas of the layer of powder material. Then, the binder material that has penetrated into the voids between the powder materials joins the powder materials to each other to form a modeled object corresponding to the two-dimensional cross-sectional layer of the three-dimensional modeled object. By alternately repeating the deposition of the powder material and the application of the binder material, the two-dimensional cross-sectional layers are laminated to form (model) a modeled article having a three-dimensional structure.

JP-A-6-218712

However, the method for manufacturing a three-dimensional structure of Patent Document 1 is to bond the powder materials to each other by the binder material applied to the powder material (modeling material), and for example, selectively irradiate a laser. The method of solidifying the modeling material, that is, the form in which the modeling material is bound is different from the method of welding and solidifying the metal material (modeling material). The strength of the obtained three-dimensional structure greatly differs depending on the binding form of this structure material. Generally, the molding method of joining powder materials with a binder material as in Patent Document 1 is inferior in strength to the method of welding and solidifying a metal material. Therefore, it has been considered to increase the strength of the three-dimensional structure by using a ceramic or metal material as the powder material and introducing a sintering process in order to improve the binding between the powder materials. However, according to this method, the material that joins the powder materials is removed (degreased) by thermal decomposition and the powder materials are sintered, so that the dimensional shrinkage of the three-dimensional structure becomes large and the shape change occurs. There was a problem that it was easy. That is, when the three-dimensional structure manufactured by the method for manufacturing the three-dimensional structure of Patent Document 1 is sintered to increase its strength, it is difficult to maintain the dimensions of the base, and the strength is higher and higher. There is a problem that it is not possible to stably form a fine three-dimensional structure.

The present invention has been made to solve at least a part of the problems described above, and can be realized as the following application examples or modes.

Application Example 1 A sintering modeling method according to this application example includes a modeling layer forming step of forming a modeling layer using a sintering modeling material containing a first inorganic particle, and a desired region of the modeling layer. A step of applying a liquid binder containing second inorganic particles, a step of curing the applied liquid binder to form a modeling cross-section layer, and a step of not applying the liquid binder of the modeling layer The method is characterized by including a step of removing a region and a step of heating and sintering the shaped cross-section layer.

The sintering modeling method of this application example includes a modeling layer forming step of forming a modeling layer using a sintering modeling material containing the first inorganic particles, and a second layer containing the second inorganic particles in a desired region of the modeling layer. And a step of curing the applied liquid binder to form a shaped cross-section layer. By including these steps, the shaped cross-sectional layer can further contain the second inorganic particles in addition to the first inorganic particles. The method also includes a step of removing a region of the shaping layer to which the liquid binder is not applied, and a step of heating the laminated shaping cross-section layers to perform a sintering treatment. By including these steps, the three-dimensional modeled object is modeled by the laminated modeled cross-section layers, and the strength can be increased by performing the sintering process.

According to this application example, since the modeling cross-section layer further contains the second inorganic particles in addition to the first inorganic particles, the density (volume filling) of the inorganic particles (first and second inorganic particles) is further increased. It is possible to obtain a three-dimensional structure having a high rate. As a result, the dimensional change (shrinkage) of the three-dimensional modeled product when the sintering process is performed is further suppressed, and the three-dimensional modeled product with higher dimensional accuracy can be modeled.

Application Example 2 In the sintering modeling method according to the above application example, in the step of performing the sintering treatment, the second inorganic particles are lower than a sintering start temperature at which the first inorganic particles start sintering. The method is characterized by including a heating step of fusing the first inorganic particles at a temperature.

According to this application example, in the step of performing the sintering treatment, the second inorganic particles are fused to the first inorganic particles at a temperature lower than the sintering start temperature at which the first inorganic particles start sintering. This allows the second inorganic particles to function as a binder that binds the first inorganic particles together. As a result, the dimensional change (shrinkage) of the three-dimensional modeled product when the sintering process is performed is further suppressed, and the three-dimensional modeled product with higher dimensional accuracy can be modeled.

Application Example 3 In the sintering modeling method according to the above application example, the sintering modeling material includes a thermoplastic binder that binds the first inorganic particles to each other, and the modeling layer forming step includes the sintering. It is characterized in that the molding material is heated to a temperature equal to or higher than the melting point of the thermoplastic binder.

According to this application example, the sintering modeling material includes the thermoplastic binder that binds the first inorganic particles to each other. The modeling layer forming step is performed by heating the sintering modeling material to a temperature equal to or higher than the melting point of the thermoplastic binder. By heating the sinter-molding material to a temperature above the melting point of the thermoplastic binder, the fluidity of the sinter-molding material is increased, making it possible to spread the sinter-molding material more easily and with higher dimensional accuracy. It becomes possible to form a modeling layer. Further, in the heating step for proceeding the sintering treatment, the thermoplastic binder contributes to the binding of the first inorganic particles until the thermoplastic binder is thermally decomposed (until degreasing is completed). According to this application example, as a result of these, it is possible to form a three-dimensional object with higher dimensional accuracy.

Application Example 4 In the sintering modeling method according to the above application example, the ratio of the weight of the first inorganic particles and the weight of the second inorganic particles included in the modeling cross-section layer is 400:1 to 3: It is characterized in that it is in the range of 1.

According to this application example, the ratio of the weight of the first inorganic particles and the weight of the second inorganic particles included in the modeling cross-section layer is in the range of 400:1 to 3:1. Can be molded using as a main material. In addition, the second inorganic particles applied to the main material makes it possible to obtain a three-dimensional structure having a higher density of inorganic particles. As a result, the dimensional change (shrinkage) of the three-dimensional modeled product when the sintering process is performed is further suppressed, and the three-dimensional modeled product with higher dimensional accuracy can be modeled.

Application Example 5 In the sintering and shaping method according to the above application example, the ratio of the average particle diameter of the first inorganic particles to the average particle diameter of the second inorganic particles is in the range of 50,000:1 to 10:1. Is characterized in that

According to this application example, since the ratio of the average particle diameter of the first inorganic particles and the average particle diameter of the second inorganic particles is in the range of 50,000:1 to 10:1, the first inorganic particles are mainly used. It can be shaped as a material, and the second inorganic particles to be applied easily penetrate between the main material (first inorganic particles) together with the liquid binder. As a result, it is possible to form a modeling cross-section layer in which the density of the inorganic particles is increased more uniformly, and it is possible to obtain a three-dimensional structure in which the density of the inorganic particles is increased more uniformly. As a result, the dimensional change (shrinkage) of the three-dimensional modeled product when the sintering process is performed is further suppressed, and the three-dimensional modeled product with higher dimensional accuracy can be modeled.

Application Example 6 In the sintering and shaping method according to the above application example, the second inorganic particles have an average particle diameter of 0.001 μm or more and 10 μm or less.

According to this application example, the average particle diameter of the second inorganic particles is 0.001 μm or more and 10 μm or less. That is, since the second inorganic particles are inorganic particles having a size of nano-particle level (10 to 10,000 nm), the liquid binder is applied to a desired region of the sintered molding material containing the first inorganic particles. In this case, the voids of the first inorganic particles can easily enter. That is, the density of the inorganic particles (first and second inorganic particles) can be increased more uniformly, and a three-dimensional structure having a more uniform density of the inorganic particles can be obtained. In addition, since the second inorganic particles are inorganic particles having a size of a nanoparticle level, the sintering start temperature of the three-dimensional structure can be lowered by adding the second inorganic particles. That is, because the size effect of the second inorganic particles causes the sintering of the second inorganic particles and the first inorganic particles to start at a lower temperature, for example, the first inorganic particles and the second inorganic particles When the same metal is used, the sintering can be started at a lower temperature than the sintering start temperature in the case of only the first inorganic particles. As a result, it is possible to suppress a dimensional change (for example, a dimensional change due to thermal decomposition (degreasing) of the binder material included in the sintering and shaping material) from a lower temperature in the heating step for the sintering process. The dimensional change (shrinkage) of the three-dimensional model is further suppressed, and the three-dimensional model having higher dimensional accuracy can be modeled.

Application Example 7 In the sintering and shaping method according to the above application example, the first inorganic particles and the second inorganic particles are ceramic particles or metal particles.

According to this application example, since the first inorganic particles and the second inorganic particles are ceramic particles or metal particles, it is possible to perform a sintering process on the three-dimensional structure whose main material is these. As a result, a stronger three-dimensional structure can be obtained.

Application Example 8 The liquid binder according to this application example includes a step of applying the liquid binder to a desired region of the sintered molding material containing the first inorganic particles, and curing the applied liquid binder. The method is used for manufacturing a three-dimensional structure including the step, and includes the second inorganic particles.

The liquid binder of this application example is a liquid binder used for manufacturing a three-dimensional structure, and is applied to a desired region of the sintered modeling material containing the first inorganic particles, and the applied region is cured. As a result, a region forming the three-dimensional structure is formed. In addition, the liquid binder contains second inorganic particles. That is, according to the liquid binder of this application example, in addition to the first inorganic particles, the second region can further include the second inorganic particles in a desired region for forming the three-dimensional structure. As a result, it is possible to obtain a three-dimensional structure having a higher density of inorganic particles.

Application Example 9 In the liquid binder according to the application example described above, the average particle diameter of the second inorganic particles is 0.001 μm or more and 10 μm or less.

According to this application example, the average particle diameter of the second inorganic particles contained in the liquid binder is 0.001 μm or more and 10 μm or less. That is, since the second inorganic particles are inorganic particles having a size of a nanoparticle level, when the liquid binder is applied to a desired region of the sintered molding material containing the first inorganic particles, It can easily enter the voids of the inorganic particles. That is, the density of the inorganic particles (first and second inorganic particles) can be increased more uniformly, and a three-dimensional structure having a more uniform density of the inorganic particles can be obtained.

Application Example 10 In the liquid binder according to the application example described above, the second inorganic particles are ceramic particles or metal particles.

According to this application example, for example, when the first inorganic particles are the same ceramic particles as the second inorganic particles, or when the first inorganic particles are the same metal particles as the second inorganic particles. In the above, it is possible to perform a sintering treatment of a three-dimensional modeled product using these as main materials, and as a result, a stronger three-dimensional modeled product can be obtained.

Application Example 11 The sintered shaped article according to this application example is characterized by being shaped by the sintering shaping method described in any one of Application Examples 1 to 7.

The sinter-molded article manufactured by the sinter-molding method described in the above application example has a three-dimensional shape with a higher dimensional accuracy in which the dimensional change (shrinkage) of the three-dimensional model when the sintering treatment is performed is further suppressed It is provided as a model.

Application Example 12 The sintered shaped article according to this application example is characterized by being molded using the liquid binder described in any one of Application Examples 8 to 10.

The sintered shaped article shaped using the liquid binder described in the above application example is provided as a three-dimensional shaped article with higher dimensional accuracy.

Application Example 13 The sintered shaped article according to this application example is included in the first inorganic particles that are contained in advance in the laminated sintering modeling material and the liquid binder that is applied to the laminated sintering modeling material. And a second inorganic particle.

According to this application example, the sinter-molded article includes the first inorganic particles contained in advance in the sinter-molded material to be laminated, and the second inorganic particles contained in the liquid binder applied to the sinter-molded material to be laminated. And particles. That is, since the sintered shaped article is configured to include the second inorganic particles in addition to the first inorganic particles, it is more inorganic than the sintered shaped article configured to include only the first inorganic particles. It is possible to obtain a sintered shaped article having a high particle packing rate.

Conceptual diagram showing the state of the sintered molding material at room temperature Schematic diagram explaining the sintering modeling device Conceptual diagram of the liquid binder according to the first embodiment A conceptual diagram showing a state in which a liquid binder is applied to a desired region of the modeling layer Conceptual diagram comparing the heat treatment process of degreasing and sintering with conventional technology

Embodiments embodying the present invention will be described below with reference to the drawings. The following is an embodiment of the present invention and does not limit the present invention. In addition, in each of the following drawings, the scale may be different from the actual scale in order to make the description easy to understand.

(Embodiment 1)
As the first embodiment, it is used for a sintering modeling material in a layered modeling, a sintering modeling apparatus, a “sintering modeling method”, and a sintering modeling as one method for modeling a three-dimensional solid model (sintered modeling). The "liquid binder" and the "sintered shaped article" shaped by these are described.
As a method of additive manufacturing, a liquid binder is selectively applied by an inkjet method to a thin layer composed of a sintering modeling material to form a cross-sectional shape of a three-dimensional structure, and a portion to which the liquid binder is applied is applied. A method of forming a three-dimensional structure by laminating one after another while curing is used.
Hereinafter, each will be specifically described.

<Sintered molding material>
FIG. 1 is a conceptual diagram showing a state of the sintered molding material 1 at room temperature (15 to 25° C.).
Sintering modeling material 1 is a material (main material) used when modeling a three-dimensional solid model (sintering modeling object) by the additive manufacturing method. That is, each layer, that is, a layer for forming each cross-sectional shape of the sintered shaped article (hereinafter referred to as a shaping layer) is formed.
The sintered molding material 1 is composed of a powder material 2 made of powder “first inorganic particles”, a binder material 3 as a “thermoplastic binder”, and the like.

The powder material 2 is a main constituent material of a sintered shaped article formed by using the sintered shaping material 1.
The powder material 2 is configured as an aggregate of the inorganic particles 2a as the "first inorganic particles". Metal particles or ceramic particles can be used as the inorganic particles 2a. The inorganic particles 2a have a substantially spherical shape with an average particle diameter of 0.1 μm or more and 30 μm or less. The average particle diameter is more preferably 1 μm or more and 15 μm or less. Moreover, it is more preferable that the shape is closer to a true sphere. This improves the controllability of the shape of the sintered shaped article, particularly the shape controllability of the sides and corners that define the outer shape of the sintered shaped article.

The particle size of the inorganic particles 2a is preferably equal to or less than the average thickness of the modeling layer formed by the sintering modeling material 1, and more preferably ½ or less of the average thickness of the modeling layer. .. As a result, the density (volume filling rate) of the inorganic particles 2a in the modeling layer can be improved, and the mechanical strength of the sintered model can be improved.

Moreover, it is preferable that the powder material 2 contains the inorganic particles 2a having different particle diameters within the above-mentioned particle diameter range. The distribution of the particle size of the inorganic particles 2a may be a distribution close to a Gaussian distribution (normal distribution), or a distribution having the maximum value of the particle size distribution on the maximum diameter side or the minimum diameter side. Dispersion).

When the particle size of the inorganic particles 2a is a single value, the volume filling rate by the inorganic particles 2a when forming the sintered shaped article exceeds 69.8% which is the theoretical value at the time of close packing. In reality, the filling rate is about 50 to 60%. On the other hand, if the powder material 2 contains the inorganic particles 2a having different particle diameters (the particle diameters are distributed over a range), for example, the inorganic particles 2a having relatively large particle diameters may be mixed with each other. The volume filling rate is improved by arranging the inorganic particles 2a having a relatively small particle size in the formed voids. Thereby, the mechanical strength of the sintered shaped article can be improved. In this way, specifically, it is preferable that the volume filling rate is about 70%.

As the powder material 2 (inorganic particles 2a), stainless alloy powder is used as a suitable example. The powder material 2 is not limited to the stainless alloy powder, and for example, copper, bronze (Cu/Sn), brass (Cu/Zn), tin, lead, gold, silver, platinum, palladium, iridium, titanium. , Powders of tantalum, iron, carbonyl iron, etc., metal alloy powders of titanium alloy, cobalt alloy, aluminum alloy, magnesium alloy, iron alloy, nickel alloy, chromium alloy, silicon alloy, zirconium alloy, gold alloy, etc. It may be a magnetic alloy powder containing Fe/Ni, Fe/Si, Fe/Al, Fe/Si/Al, Fe/Co, Fe/Co/V or the like, or an intermetallic compound powder such as titanium aluminum. In the case of ceramic powder, alumina powder, zirconia powder, etc. may be used.

The binder material 3 is a thermoplastic polymer compound, and when the powder material 2 and the binder material 3 are mixed in the sintering molding material 1 to disperse the inorganic particles 2a substantially uniformly, the inorganic particles 2a are bound to each other. Have the function to As shown in FIG. 1, when the powder material 2 and the binder material 3 are mixed so as to be dispersed substantially uniformly, the binder material 3 binds the inorganic particles 2a as, for example, flake-shaped binder flakes 3a. There is.

As the binder material 3, for example, as a suitable example, polycaprolactone diol having a melting point of 55° C. to 58° C. and a thermal decomposition starting temperature of about 200° C. is used.
The binder material 3 is not limited to polycaprolactone diol, and a material having solid thermoplasticity at room temperature and having a thermal decomposition starting temperature of 50° C. or higher and lower than the sintering temperature of the inorganic particles 2a is used. For example, ethylene vinyl acetate copolymer having a melting point of 50 to 100° C. and a thermal decomposition starting temperature of about 250° C., polyethylene having a melting point of about 120° C. and a thermal decomposition starting temperature of about 400° C., and the like may be used.
At room temperature, each is a solid such as wax, petrolatum, and flakes, and melts above the melting point to become a liquid.

The higher the filling rate of the inorganic particles 2a constituting the powder material 2 in the sintered shaped article, the higher the accuracy of the shape of the sintered shaped article. Therefore, in order to enhance the accuracy of the shape of the sintered shaped article, the volume occupied by the binder material 3 is smaller than the voids of the densely packed inorganic particles 2a so that the inorganic particles 2a are densely packed. Such a blending ratio is preferable. Therefore, the volume ratio of the powder material 2 to the binder material 3 is preferably in the range of 7:3 to 9:1.

The sintered molding material 1 may contain a solvent. As the solvent, an aqueous solvent containing a non-organic solvent such as water and an aqueous solution of an inorganic salt is preferable. It is more preferable to use water as the aqueous solvent. By including the solvent in the sinter-molding material 1, it is possible to more easily obtain a paste-form sinter-molding material in which the powder material 2 is uniformly dispersed. Further, the solvent makes it easier to spread the paste-shaped sintered molding material, so that the molding layer can be formed thinner.

<Sintering modeling device>
FIG. 2 is a schematic diagram for explaining the sintering modeling apparatus 100.
In FIG. 2, the Z-axis direction is the vertical direction, the -Z direction is the vertical direction, the Y-axis direction is the front-back direction, the +Y direction is the front direction, the X-axis direction is the left-right direction, the +X direction is the left direction, and the XY plane is The surface is parallel to the plane on which the sintering modeling apparatus 100 is installed.

The sinter modeling apparatus 100 is an apparatus that uses the sinter modeling material 1 to model a three-dimensional solid model (sinter model) by a layered modeling method.
The sintering and shaping apparatus 100 controls the material supply unit 10, the heating unit 20, the spreading unit 30, the shaping unit 40, the drawing unit 50, the curing unit 60, the revealing unit 70, the degreasing and sintering unit 80, and each. A unit (not shown) and the like are provided.

The material supply unit 10 is a unit that supplies the housed sintered modeling material 1 to the heating unit 20, and includes a hopper 11 as shown in FIG. 2, for example. The hopper 11 supplies the sintering molding material 1 housed therein to the heating unit 20 through the material discharge port 12 located above the heating unit 20.
Note that the material supply unit 10 is not limited to this configuration, and includes, for example, a loading unit that loads and heats the cartridge containing the sintering and shaping material 1, and the loaded cartridge has a temperature equal to or higher than the melting point of the binder material 3. A configuration (not shown) in which the sintered modeling material 1 is made fluid by heating and is supplied to the heating unit 20 may be used.

The heating unit 20 includes a hot plate 21 that heats and maintains the sintering modeling material 1 at a temperature equal to or higher than the melting point of the binder material 3. The sintering molding material 1 supplied from the material supply unit 10 becomes a fluid molding material 4 having fluidity by melting the binder material 3 on the hot plate 21.

The spreading section 30 includes a squeegee 31.
The squeegee 31 is an elongated plate-like member that is provided so as to be movable in the X-axis direction and that extends in the Y-axis direction. The squeegee 31 moves the fluid molding material 4 so as to rub it in the -X direction on the XY plane. As a result, the flowable molding material 4 can be spread thinly.
The spreading unit 30 spreads the fluid modeling material 4 on the stage 41 included in the modeling unit 40 to form the modeling layer 5.
The method of thinly spreading the fluid modeling material 4 is not limited to the method of spreading with the squeegee 31. For example, a method of pressing and spreading with air, a method of rotating a stage equipped with a heating unit and spreading with a centrifugal force, and the like may be used.

The modeling unit 40 includes a stage 41 and a stage elevating mechanism 42 that elevates and lowers the stage 41 in the Z-axis direction. The stage 41 constitutes an XY plane on which the fluid molding material 4 is spread by the squeegee 31 at an initial position located in the same plane (same height) as the hot plate 21.

The stage 41 is maintained at room temperature (for example, room temperature), and the fluidity modeling material 4 spread on the stage 41 loses fluidity when the temperature is lower than the melting point, and a new modeling is performed on the modeling layer 5 previously formed. Stacked as layer 5. The spreadable flowable molding material 4 may be left to stand until it is below the melting point, or may be cooled. As a cooling method, a method of blowing normal temperature or cooled air to the modeling layer 5 using a fan or a method of bringing a cooling plate into contact with the modeling layer 5 is possible.

The stage elevating mechanism 42 lowers the stage 41 according to the layer thickness of the modeling layer 5 that is spread and formed on the stage 41. When the stage 41 descends, the surface of the modeling layer 5 comes to be located in the same plane (same height) as the hot plate 21, and the squeegee 31 spreads the fluid modeling material 4 again to model it. An XY plane is formed which is laminated as layer 5.

The drawing unit 50 includes an ejection head 51, a cartridge loading unit 52, a carriage 53, a carriage moving mechanism 54 (configuration diagram omitted), and the like.
The ejection head 51 includes a nozzle (not shown) that ejects the liquid binder 8 onto the modeling layer 5 on the stage 41 by an inkjet method.
The cartridge loading unit 52 loads an ink cartridge containing the liquid binder 8 and supplies the liquid binder 8 to the ejection head 51.
The carriage 53 has an ejection head 51 and a cartridge loading unit 52 (that is, an ink cartridge) mounted thereon, and is moved on the upper surface of the stage 41 by a carriage moving mechanism 54.
The carriage moving mechanism 54 has an X-Y axis linear transfer mechanism, and moves (scans) the carriage 53 on the XY plane.

Under the control of the control unit, the drawing unit 50 forms a desired image (image reflecting the cross-sectional shape of the sintered shaped object) on the modeling layer 5 spread on the stage 41 by the liquid binder 8. Specifically, the control unit has pre-input image information of each cross-sectional layer forming the sintered shaped article, and according to the image information, the position to move the ejection head 51 and the liquid binder 8 are set. The ejection timing is controlled, and the liquid binder 8 is applied to each corresponding modeling layer 5.

The curing unit 60 includes a liquid binder curing mechanism 61 that cures the liquid binder 8 applied to the modeling layer 5 to form the modeling cross-section layer 6. For example, when a material containing an ultraviolet curable resin is used for the liquid binder 8, the liquid binder curing mechanism 61 is configured by an ultraviolet irradiator, and, for example, the liquid binder 8 contains a thermosetting resin. When a material is used, the liquid binder curing mechanism 61 is composed of a heating device.

The exposed portion 70 is a portion that exposes the molded article 7 by removing the region (non-molded portion 5b) of the modeling layer 5 to which the liquid binder 8 is not applied, and is arranged on the −X side of the modeling portion 40. Has been done. The exposed portion 70 is provided with an unnecessary portion removing device (not shown) such as a cutting knife or a rotating brush, and with respect to the modeled object (laminated product of the modeling layer 5) transferred from the modeling section 40 by the transfer mechanism 43. Perform appearance processing.
The revealing process may be a method of rinsing and removing the non-shaped part 5b by rinsing with water when the binder material 3 is water-soluble, so that it is configured to include a rinsing tank as an unnecessary part removing means. May be.

The degreasing and sintering part 80 is a part for degreasing and sintering the modeled object 7 (the laminated modeling cross-section layer 6) from which the non-modeling part 5b has been removed, and is arranged on the −X side of the exposed part 70. ing. The degreasing and sintering unit 80 includes a degreasing and sintering furnace 81, a heater 82, a degreasing gas supply facility 83, an exhaust facility 84, and the like, and with respect to the modeled object 7 that is transported from the revealing unit 70 by the transport mechanism 43. Degreasing and sintering treatment is performed.

The sintering modeling apparatus 100 has been described by taking the configuration in which the revealing section 70 and the degreasing and sintering section 80 are continuously provided from the modeling section 40 as an example, but the configuration is not limited to this. For example, the exposed portion 70 and the degreasing and sintering portion 80, or the exposing portion 70 and the degreasing and sintering portion 80 may be configured separately.

<Liquid binder>
FIG. 3 is a conceptual diagram of the liquid binder 8 as the “liquid binder” according to the first embodiment.
The liquid binder 8 is characterized in that the liquid portion 9 in the liquid state contains inorganic particles 8a as "second inorganic particles". Further, the liquid portion 9 contains a curing agent 8b.

As the inorganic particles 8a, metal particles or ceramic particles can be used as in the case of the inorganic particles 2a. As a suitable example, stainless alloy powder is used as in the case of the inorganic particles 2a. The inorganic particles 8a are not limited to stainless alloys, and include, for example, copper, bronze (Cu/Sn), brass (Cu/Zn), tin, lead, gold, silver, platinum, palladium, iridium, titanium, Tantalum, iron, carbonyl iron, etc., metal alloys such as titanium alloy, cobalt alloy, aluminum alloy, magnesium alloy, iron alloy, nickel alloy, chromium alloy, silicon alloy, zirconium alloy, gold alloy, Fe/Ni, It may be a magnetic alloy containing Fe/Si, Fe/Al, Fe/Si/Al, Fe/Co, Fe/Co/V, or an intermetallic compound such as titanium aluminum. Further, in the case of ceramic, alumina, zirconia or the like may be used.

The inorganic particles 8a have a substantially spherical shape with an average particle diameter of 0.001 μm or more and 10 μm or less. The average particle diameter of the inorganic particles 8a is more preferably 0.001 μm or more and 5 μm or less, and the closer to a true spherical shape, the more preferable. The ratio of the average particle size of the inorganic particles 2a and the average particle size of the inorganic particles 8a is in the range of 50,000:1 to 10:1. This allows the inorganic particles 8a to easily enter the voids of the inorganic particles 2a. That is, the density of the inorganic particles (the inorganic particles 2a and the inorganic particles 8a) can be increased more uniformly, and a three-dimensional structure having the inorganic particles more uniformly increased in density can be obtained.

As the curing agent 8b, an ultraviolet curable resin (ultraviolet polymerizable compound) is used as a suitable example, but the curing agent 8b is not limited to this and may be, for example, a thermoplastic resin, a thermosetting resin, or a light in the visible light range. Visible light curable resin (light curable resin in a narrow sense) that cures, various light curable resins such as infrared curable resin, X-ray curable resin, etc., and one or more kinds selected from these are combined. It may be configured.

The liquid binder 8 (liquid part 9) is, for example, a dispersant, a surfactant, a polymerization initiator, a polymerization accelerator, a solvent, a penetration accelerator, a wetting agent (humectant), a fixing agent, a fungicide, It may contain components such as an antiseptic, an antioxidant, an ultraviolet absorber, a chelating agent, a pH adjusting agent, a thickener, an anti-agglomeration agent, and an antifoaming agent.

<Sintering modeling method>
Next, the “sintering modeling method” for modeling the “sintering model” using the sintering modeling apparatus 100 using the above-described sintering modeling material 1 and the liquid binder 8 will be described.
The sintering modeling method according to the present embodiment includes the following steps.
(1) Forming layer forming step of forming the forming layer 5 using the sintering forming material 1 containing the inorganic particles 2a (2) Applying the liquid binder 8 containing the inorganic particles 8a to a desired region of the forming layer 5 Step (3) Step of curing the applied liquid binder 8 to form the modeling cross-section layer (4) Step of removing a region of the modeling layer 5 to which the liquid binder 8 is not applied (5) Lamination Step of heating the shaped cross-section layer 6 and sintering treatment

Hereinafter, description will be made in order with reference to FIG.
In addition, from the step after the sintering modeling material 1 is supplied to the sintering modeling apparatus 100 to the step of performing the sintering process of the molded article 7, the control is performed by the control unit included in the sintering modeling apparatus 100.

First, the sintering modeling material 1 including the inorganic particles 2a and the binder material 3 is prepared and filled in the material supply unit 10 (hopper 11). The respective ratios are appropriately determined according to the molding specifications of the sintered molded product such as the particle size of the inorganic particles 2a, the particle size distribution, the volume filling rate of the inorganic particles 2a, and the layer thickness of the modeling layer 5 formed by spreading. It is desirable to set. Specifically, for example, the volume filling rate of the inorganic particles 2a is set to about 70%. Further, it is preferable that the respective dispersions are uniform.

Further, the liquid binder 8 including the inorganic particles 8a and the curing agent 8b is prepared, filled in the ink cartridge, and set in the cartridge loading portion 52.
As a suitable example, inorganic particles made of the same material as the inorganic particles 2a are used as the inorganic particles 8a, but the present invention is not limited to this. The amount of the inorganic particles 8a contained in the liquid binder 8 is such that the ratio of the weight of the inorganic particles 2a contained in the formed modeling cross-section layer 6 to the weight of the inorganic particles 8a is in the range of 400:1 to 3:1. Adjust so that Specifically, as a preferred example, the ratio of the weight of the inorganic particles 2a and the weight of the inorganic particles 8a to the inorganic particles 2a adjusted to have a volume filling rate of about 70% in the sintered molding material 1. Is adjusted to be 9.5:1, and the content of the inorganic particles 8a is adjusted.
As the curing agent 8b, a UV curable resin is used as a suitable example.

Next, the sintering molding material 1 is supplied from the material supply unit 10 to the heating unit 20 (hot plate 21). The amount of the sintering modeling material 1 supplied to the heating unit 20 at one time is controlled to be an amount corresponding to the amount of one modeling layer 5.
The heating unit 20 heats the sintering molding material 1 to a temperature equal to or higher than the melting point of the binder material 3 by the hot plate 21 and melts the binder material 3 to form the fluid molding material 4.

Next, the flowable molding material 4 is spread on the stage 41 by the spreading part 30. Specifically, the squeegee 31 brought into contact with the +X side of the fluidity-based sintered modeling material 1 (fluidic modeling material 4) is moved in the −X direction to be pushed to the surface of the stage 41.

The stage 41 is maintained at room temperature (for example, room temperature), and the fluid modeling material 4 spread on the stage 41 is cooled to room temperature. When the fluidity modeling material 4 is cooled to room temperature, the binder material 3 is solidified, the modeling layer 5 is formed, and the modeling layer forming step is completed.
The layer thickness of the modeling layer 5 is controlled by the specification of spreading by the squeegee 31. Specifically, the layer thickness of the modeling layer 5 is the size of the gap between the lower end of the squeegee 31 and the XY plane (for example, the surface of the stage 41 at the initial position), the moving speed of the squeegee 31, and the fluid modeling material 4. Since it changes depending on the viscosity of the above, it is desirable to appropriately set the thickness so as to obtain a desired thickness.

Next, the drawing unit 50 applies the liquid binder 8 containing the inorganic particles 8 a to a desired region of the modeling layer 5 formed on the stage 41, and forms a desired image with the liquid binder 8. Specifically, the liquid binder 8 is ejected while moving the ejection head 51 in accordance with the image information of each cross-sectional layer that constitutes the sintered shaped object that is input to the control unit in advance, and the sintered shaped object is The liquid binder 8 is applied to the position corresponding to the cross-sectional shape.

FIG. 4 is a conceptual diagram showing a state in which the liquid binder 8 is applied to a desired region of the modeling layer 5 by the sintering modeling apparatus 100.
The binder material 3 that has been dispersed in the form of flakes in FIG. 1 is once melted and solidified to increase the volume filling rate of the inorganic particles 2a, and to cover the surface of the inorganic particles 2a so that the entire modeling layer 5 is substantially covered. Evenly distributed. As shown in FIG. 4, the liquid binder 8 selectively applied to a desired position permeates the region containing the inorganic particles 2a and the binder material 3 (the void portion of the inorganic particles 2a covered with the binder material 3). Then, the modeling portion 5a is formed. In addition, the inorganic particles 8a having a smaller particle size than the inorganic particles 2a enter into the gaps between the inorganic particles 2a as the liquid binder 8 (the liquid portion 9) penetrates into the modeling layer 5.

Next, the curing section 60 cures the liquid binder 8 applied to the modeling layer 5 to form the modeling cross-section layer 6. Specifically, since the liquid binder 8 containing an ultraviolet curable resin is used as a suitable example, after the carriage 53 is evacuated from the stage 41, an ultraviolet irradiator (liquid binder curing mechanism 61) is used. The modeling layer 5a is cured by irradiating the modeling layer 5 with ultraviolet rays to cure the liquid binder 8 applied to the modeling layer 5.
The liquid binder 8 is preferably cured to such an extent that the curing is not completed in order to maintain the bonding strength at the interface with the liquid binder 8 applied to the modeling layer 5 to be laminated next.

Next, the stage elevating mechanism 42 lowers the stage 41 according to the layer thickness of the modeling layer 5 formed by being spread on the stage 41. When the stage 41 descends, the surface of the modeling layer 5 comes to be located in the same plane as the hot plate 21, and the fluid modeling material 4 is spread again by the squeegee 31 and laminated as the modeling layer 5. An XY plane is constructed.

After that, the steps from the step of supplying the sintering modeling material 1 from the material supply unit 10 to the heating unit 20 to the above steps are repeated to stack the modeling layer 5. That is, the second and subsequent modeling layers 5 are stacked on the previously formed modeling layer 5.
Alternatively, the step of forming the modeling layer 5 by spreading the fluid modeling material 4 may be performed at a place other than the stage 41, and the modeling layer 5 may be sequentially transferred to the stage 41 to be laminated.

When the stacking of the modeling layer 5 reaches the height corresponding to the modeling of the modeled article 7 and the stacking is completed, the modeled layer 40 is taken out, and the modeled article 7 is exposed. Specifically, the transporting mechanism 43 transports the modeled object (laminated product of the modeling layer 5) from the modeling section 40 to the revealing section 70, and the non-modeling section 5b to which the liquid binder 8 is not applied by the unnecessary portion removing means. Then, the molded article 7 (laminated modeling cross-section layer 6) is exposed.

Next, the modeled object 7 that has been exposed is transferred to the degreasing and sintering unit 80, where it is degreased. Specifically, first, the molded article 7 is transported from the exposed portion 70 to the inside of the degreasing and sintering furnace 81 by the transport mechanism 43, and the molded article 7 is degreased. Degreasing is performed for the purpose of thermally decomposing and removing the binder material 3 and the applied and cured liquid binder 8 (curing agent 8b). In the degreasing step, heat treatment is performed at a temperature range in which debinding of the binder material 3 starts (in a preferred example, a temperature (300° C.) exceeding the thermal decomposition start temperature (about 200° C.) of polycaprolactone diol), and the binder material 3 And degreasing of the liquid binder 8 (curing agent 8b) is promoted. Decomposition components generated by thermal decomposition of the binder material 3 and the liquid binder 8 (curing agent 8b) are discharged from the exhaust equipment 84 by the degreasing gas supplied from the degreasing gas supply equipment 83.

Next, the degreased shaped article 7 is sintered. Specifically, the temperature is further gradually increased to a temperature higher than the temperature at which the degreasing treatment is performed, and the heat treatment is performed at a temperature at which the inorganic particles 2a are sintered. As a preferred example, for example, when a stainless alloy powder is used for the inorganic particles 2a, the heating temperature is gradually raised to 1300° C. at which the stainless alloy is sintered. By completing the sintering of the inorganic particles 2a and the inorganic particles 8a, a desired sintered shaped article can be obtained.

In the heating step of gradually increasing the heating temperature, the temperature of the inorganic particles 8a is lower than the sintering start temperature at which the inorganic particles 2a start to be sintered (the sintering start temperature in the case of sintering only the inorganic particles 2a). In (1), it can be fused to the inorganic particles 2a). This is due to the size effect (melting point decrease) in which the sintering start temperature can be lowered by adding the inorganic particles 8a, because the inorganic particles 8a are the inorganic particles having a size of the nanoparticle level.

FIG. 5 is a conceptual diagram comparing a heat treatment process of degreasing and sintering with a conventional technique (when the liquid binder 8 does not include the inorganic particles 8a). It is shown that the way in which the main materials (inorganic particles) forming the sintered shaped article are bound changes according to the transition of the heat treatment temperature.
The main material (inorganic particles 2a) is supported by the binder material and the applied and cured liquid binder, but in the degreasing step (zone A shown in FIG. 5), the binder material and the applied and cured liquid binder are Since it is gradually decomposed by heating, the force for binding the main material (inorganic particles 2a) gradually weakens. This is the same both in the prior art and in this embodiment.

While the degreasing is completed, the heating temperature is gradually increased, and the heat treatment is continued until the sintering is completed (zones B and C shown in FIG. 5), the state of supporting the main material (inorganic particles) is Different from the prior art.
In the conventional technique, the force for binding the main material (inorganic particles 2a) is extremely small in the range (zone B shown in FIG. 5) from the completion of degreasing to the start of sintering of the inorganic particles. Therefore, the dimensional change of the modeled article 7 is likely to occur together with the effect that the volume filling rate of the inorganic particles is lower than that of the present embodiment (because only the inorganic particles 2a are included).
On the other hand, in the present embodiment, the fusion of the inorganic particles 8a and the inorganic particles 2a starts in the same zone B, and the volume filling rate of the inorganic particles is higher than that of the conventional technique (inorganic particles Since the inorganic particles 8a enter the voids 2a), the dimensional change of the molded article 7 is unlikely to occur.

Further, the fusion of the inorganic particles 8a and the inorganic particles 2a may start during the degreasing step (in this case, the fusion start temperature is the thermal decomposition start of the binder material 3 and the liquid binder 8 (curing agent 8b)). Low temperature). By doing so, before the binder material 3 and the liquid binder 8 (curing agent 8b) are degreased and the force for binding the main material (inorganic particles 2a) is minimized, the melting of the inorganic particles 8a and the inorganic particles 2a is performed. Since the wearing starts, the dimensional change of the molded article 7 is unlikely to occur. Further, fusion with the inorganic particles 2a may start after the degreasing step is completed. (In this case, the fusion start temperature is the low thermal decomposition start temperature of the binder material 3 and the liquid binder 8 (curing agent 8b)). By doing so, since the inorganic particles 2a are mixed in the voids of the main material (inorganic particles 2a) and the main material (inorganic particles 2a), the binder material 3 and the liquid binder 8 (curing agent 8b) are mixed. Even if degreased, the main material (inorganic particles 2a) is hard to move, and the dimensional change of the molded article 7 is hard to occur.

As described above, according to the sintering modeling method, the liquid binder used for sintering modeling, and the sintering model according to the present embodiment, the following effects can be obtained.
The sintering modeling method of the present embodiment includes a modeling layer forming step of forming the modeling layer 5 using the sintering modeling material 1 containing the inorganic particles 2a, and the inorganic particles 8a included in a desired region of the modeling layer 5. The method includes a step of applying the liquid binder 8 and a step of curing the applied liquid binder 8 to form the modeling cross-section layer 6. By including these steps, the modeling cross-section layer 6 can further include the inorganic particles 8a in addition to the inorganic particles 2a. Further, the method includes a step of removing a region of the modeling layer 5 to which the liquid binder 8 is not applied, and a step of heating the stacked modeling cross-section layers 6 and performing a sintering process. By including these steps, a three-dimensional model (sintered model) is modeled by the laminated model cross-section layers 6, and the strength can be increased by performing a sintering process.

Moreover, since the modeling cross-section layer 6 further includes the inorganic particles 8a in addition to the inorganic particles 2a, a sintered modeled product having a higher density (volume filling rate) of the inorganic particles can be obtained. As a result, the dimensional change (shrinkage) of the sintered shaped article when the sintering process is performed is further suppressed, and the sintered shaped article with higher dimensional accuracy can be formed.

Further, the inorganic particles 8a function as a binder for binding the inorganic particles 2a to each other by fusing the inorganic particles 2a to the inorganic particles 2a at a temperature lower than the sintering start temperature at which the inorganic particles 2a start sintering. Can be made. As a result, the dimensional change (shrinkage) of the sintered shaped article when the sintering process is performed is further suppressed, and the sintered shaped article with higher dimensional accuracy can be formed.

In addition, the sintering modeling material 1 includes a thermoplastic binder material 3 that binds the inorganic particles 2 a to each other. In the modeling layer forming step, the sintering modeling material 1 is heated to a temperature equal to or higher than the melting point of the binder material 3. Then do. Since the fluidity of the sintered molding material 1 is increased by heating the sintered molding material 1 to a temperature equal to or higher than the melting point of the binder material 3, the sintered molding material 1 can be spread more easily, and the size can be further increased. It becomes possible to form the modeling layer 5 with high accuracy. In addition, in the heating step that advances the sintering process, the binder material 3 contributes to the binding of the inorganic particles 2a until the binder material 3 is thermally decomposed (until degreasing is completed). According to the present embodiment, as a result of these, it is possible to form a sintered shaped article with higher dimensional accuracy.

Moreover, since the ratio of the weight of the inorganic particles 2a and the weight of the inorganic particles 8a included in the modeling cross-section layer 6 is in the range of 400:1 to 3:1, it is possible to mold the inorganic particles 2a as the main material. Further, by the inorganic particles 8a added to the main material, it is possible to obtain a sintered shaped article having a higher density of inorganic particles. As a result, the dimensional change (shrinkage) of the sintered shaped article when the sintering process is performed is further suppressed, and the sintered shaped article with higher dimensional accuracy can be formed.

Moreover, since the ratio of the average particle diameter of the inorganic particles 2a and the average particle diameter of the inorganic particles 8a is in the range of 50,000:1 to 10:1, the inorganic particles 2a can be molded using the main material as a main material, and imparting The inorganic particles 8a to be formed easily penetrate between the liquid binder 8 and the main material (inorganic particles 2a). As a result, it is possible to form the shaped cross-section layer 6 in which the density of the inorganic particles is increased more uniformly, and it is possible to obtain the sintered shaped article in which the density of the inorganic particles is increased more uniformly. As a result, the dimensional change (shrinkage) of the sintered shaped article when the sintering process is performed is further suppressed, and the sintered shaped article with higher dimensional accuracy can be formed.

The average particle diameter of the inorganic particles 8a is 0.001 μm or more and 10 μm or less. That is, when the liquid binder 8 is applied to a desired region of the sintered molding material 1 containing the inorganic particles 2a, since the inorganic particles 8a are inorganic particles having a size of a nanoparticle level (10 to 10,000 nm). In addition, it can easily enter the voids of the inorganic particles 2a. That is, the density of the inorganic particles can be increased more uniformly, and a sintered shaped article with the density of the inorganic particles increased more uniformly can be obtained. Further, since the inorganic particles 8a are inorganic particles having a size of nano-particle level, the sintering start temperature of the sintered shaped article can be lowered by adding the inorganic particles 8a. That is, because of the size effect of the inorganic particles 8a, the sintering of the inorganic particles 8a and the inorganic particles 2a is started at a lower temperature. For example, when the inorganic particles 2a and the inorganic particles 8a are the same metal, Sintering can be started at a lower temperature than the sintering start temperature in the case of only particles 2a. As a result, it is possible to suppress a dimensional change (for example, a dimensional change due to thermal decomposition (degreasing) of the binder material 3 included in the sintering modeling material 1) in a heating step for the sintering process from a lower temperature. Therefore, the dimensional change (shrinkage) of the sintered shaped article is further suppressed, and the sintered shaped article with higher dimensional accuracy can be formed.

Further, since the inorganic particles 2a and the inorganic particles 8a are ceramic particles or metal particles, it is possible to perform a sintering process on the sintered molded product of the main material, and as a result, a stronger sintered molded product can be obtained. You can get things.

The liquid binder 8 of the present embodiment is a liquid binder 8 used for manufacturing a sintered shaped article, and is applied to a desired area of the sintered molding material 1 containing the inorganic particles 2a, and the applied area is cured. By doing so, a region constituting the sintered shaped article is formed. Further, the liquid binder 8 contains inorganic particles 8a. That is, according to the liquid binder 8 of the present embodiment, in addition to the inorganic particles 2a, the inorganic particles 8a can be further included in a desired region for forming the sintered shaped article. As a result, it is possible to obtain a sintered shaped article having a higher density of inorganic particles.

The average particle size of the inorganic particles 8a contained in the liquid binder 8 is 0.001 μm or more and 10 μm or less. That is, since the inorganic particles 8a are inorganic particles having a size of a nanoparticle level, when the liquid binder 8 is applied to a desired region of the sintered molding material 1 containing the inorganic particles 2a, the inorganic particles 2a are It can easily enter the void. That is, the density of the inorganic particles (the inorganic particles 2a and the inorganic particles 8a) can be increased more uniformly, and a sintered shaped article in which the density of the inorganic particles is increased more uniformly can be obtained.

Further, for example, when the inorganic particles 2a contained in the sintered molding material 1 are ceramic particles similar to the inorganic particles 8a contained in the liquid binder 8, or the inorganic particles 2a contained in the sintered molding material 1 are liquid. In the case of the same metal particles as the inorganic particles 8a contained in the binder 8, it is possible to perform a sintering process of a sintered shaped product using these as a main material, and as a result, a stronger solid shaped molded product can be obtained. Obtainable.

The sinter modeled by the sinter modeling method described above, that is, the sinter modeled using the liquid binder 8 is included in the sinter model material 1 to be laminated in advance. A sintered molded article including the inorganic particles 2a and the inorganic particles 8a contained in the liquid binder 8 applied to the laminated sintered modeling material 1 is a sintered product obtained by performing a sintering process. The dimensional change (shrinkage) of the modeled object is further suppressed, and it is provided as a sintered modeled object with higher dimensional accuracy.

DESCRIPTION OF SYMBOLS 1... Sintered modeling material, 2... Powder material, 2a... Inorganic particle, 3... Binder material, 3a... Binder flake, 4... Fluid modeling material, 5... Modeling layer, 5a... Modeling part, 5b... Non-modeling part, 6... Modeling cross-section layer, 7... Modeling object, 8... Liquid binder, 8a... Inorganic particles, 8b... Curing agent, 9... Liquid part, 10... Material supply part, 11... Hopper, 12... Material discharge port, 20... Heating part, 21... Hot plate, 30... Spreading part, 31... Squeegee, 40... Modeling part, 41... Stage, 42... Stage elevating mechanism, 43... Conveying mechanism, 50... Drawing part, 51... Ejecting head, 52... Cartridge loading section, 53... Carriage, 54... Carriage moving mechanism, 60... Curing section, 61... Liquid binder curing mechanism, 70... Exposing section, 80... Degreasing and sintering section, 81... Degreasing and sintering furnace, 82... Heating Heater, 83... Degreasing gas supply equipment, 84... Exhaust equipment, 100... Sinter molding device.

Claims (3)

A material supply unit for supplying a sintering molding material containing the first inorganic particles onto the stage;
A spreading portion that spreads the sintered molding material to form a molding layer,
A drawing unit for applying a thermoplastic resin containing second inorganic particles to a desired region of the modeling layer;
An exposed portion for removing a region to which the thermoplastic resin of the shaping layer is not applied,
Degreasing the thermoplastic resin from the modeling layer, a degreasing and sintering unit that heats and sintering the modeling layer,
A control unit for controlling the degreasing and sintering unit,
The sintering start temperature of the second inorganic particles is equal to or higher than the thermal decomposition start temperature of the thermoplastic resin and is equal to or lower than the sintering start temperature of the first inorganic particles,
In the control unit, the degreasing and sintering unit heats the modeling layer at a temperature that is equal to or higher than a sintering start temperature of the second inorganic particles and is equal to or lower than a sintering start temperature of the first inorganic particles, and the heat treatment is performed. A first control for fusing the second inorganic particles to the first inorganic particles before the force for binding the first inorganic particles to the minimum by degreasing the plastic resin;
The sintering modeling apparatus, wherein the degreasing and sintering unit executes a second control of heating the modeling layer at a temperature equal to or higher than a sintering start temperature of the first inorganic particles. The degreasing and sintering unit includes a degreasing and sintering furnace, a heater, a degreasing gas supply facility, and an exhaust facility,
The sintering modeling apparatus according to claim 1, wherein the exhaust facility discharges a decomposition component generated by thermal decomposition of the thermoplastic resin by a degreasing gas. The modeling part including the stage, the exposed part, and the degreasing and sintering part are continuously provided in the order of the modeling part, the revealing part, and the degreasing and sintering part. The described sintering modeling apparatus.

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