JP7528586B2 - 3D modeling apparatus and 3D modeling method - Google Patents

Description

The present invention relates to a three-dimensional modeling device and a three-dimensional modeling method.

In recent years, the creation of three-dimensional objects has been utilized in a variety of fields.

For example, Patent Document 1 discloses a configuration in which excess molding material on the forward direction side of a flattening member that flattens a modeling layer made of molding material is sucked up and reused.

However, the configuration of Patent Document 1 requires a means for sucking out excess molding material, which can make the device complicated.

The present invention aims to create shapes while reusing excess molding materials using simple means.

In order to solve the above-mentioned problems, a three-dimensional modeling device that forms a three-dimensional object on a modeling table has a flying unit that shoots powder-like modeling material and causes it to land on a first region on the modeling table, a heating unit that heats the modeling material in a second region within the first region, and a support formation unit that forms a support for the modeling material in the second region around the second region using surplus modeling material, wherein the support formation unit has a region determination unit that determines the first region, and a moving unit that moves the surplus modeling material in the second region around the second region, wherein the moving unit moves the surplus modeling material in the second region in a predetermined direction, and the region determination unit determines the first region in accordance with the predetermined direction .

The present invention allows for easy modeling while reusing excess modeling material.

1 is a diagram illustrating an example of the overall configuration of a three-dimensional object forming apparatus according to a first embodiment. FIG. 4 illustrates an example of a functional configuration of a control unit. FIG. 4 is a flowchart showing an example of an overall operation of the three-dimensional object forming apparatus according to the first embodiment. 5A and 5B are diagrams showing an example of the operation of a flattening mechanism, in which FIG. 5A shows an example of the operation of a flattening roller, and FIG. 5B shows an example of the operation of a flattening blade. 1A and 1B are diagrams of examples of the first and second regions, where (a) is a diagram of the first region, (b) is a cross-sectional view taken along the line A-A in (a), (c) is a diagram of the second region, and (d) is a cross-sectional view taken along the line B-B in (c). 5A to 5F are diagrams illustrating an example of a modeling operation by the three-dimensional modeling apparatus according to the first embodiment, in which FIG. FIG. 2 is a cross-sectional view illustrating the angle of repose. 1A and 1B are diagrams of various examples of determining the first region, where (a) is a diagram of the first example, (b) is a cross-sectional view taken along the line CC of (a), (c) is a diagram of the second example, (d) is a cross-sectional view taken along the line D-D of (c), (e) is a diagram of the third example, and (f) is a cross-sectional view taken along the line E-E of (e). FIG. 13 is a diagram of a fourth determination example of the first region. FIG. 13 is a diagram illustrating an example of the overall configuration of a three-dimensional object forming apparatus according to a second embodiment. 5A and 5B are diagrams showing examples of the operation of the flattening roller, in which FIG. 5A is a diagram of a first example, and FIG. 5B is a diagram of a second example. 5A and 5B are diagrams illustrating an example of a peripheral configuration of a flattening roller. FIG. 11 is a flowchart showing an example of the operation of the three-dimensional object forming apparatus according to the second embodiment.

Below, an embodiment of the present invention will be described with reference to the drawings. Note that in each drawing, the same components are given the same reference numerals, and duplicated explanations will be omitted as appropriate. Furthermore, the embodiment shown below is an example of a three-dimensional modeling device for embodying the technical concept of the present invention, and the present invention is not limited to the embodiment shown below.

The dimensions, materials, shapes, relative positions, etc. of the components described below are intended to be illustrative and not to limit the scope of the present invention unless otherwise specified. In addition, the sizes and positional relationships of the components shown in the drawings may be exaggerated for clarity of explanation.

The three-dimensional modeling apparatus according to the embodiment is a three-dimensional modeling apparatus that models a three-dimensional object on a modeling table.

In this embodiment, the modeling material is ejected and lands on a first region on the modeling table, the modeling material in a second region within the first region is heated, and a support for supporting the modeling material in the second region is formed around the second region using surplus modeling material. The surplus modeling material generated by planarizing the modeling layer surface is reused as a support simultaneously (in parallel) with the planarization of the modeling layer surface, making it possible to model while reusing the surplus modeling material using a simple method. Here, surplus modeling material refers to modeling material that is not used as a model that constitutes a three-dimensional object.

In the embodiment, a structure that is in the process of being modeled is simply referred to as a modeled object, and a structure that has been completed is referred to as a three-dimensional object to distinguish between the two.

[First embodiment]
First, a three-dimensional object forming apparatus 100 according to the first embodiment will be described.

<Overall configuration example of 3D object formation apparatus 100>
The overall configuration of a three-dimensional object forming apparatus 100 will be described with reference to Fig. 1. Fig. 1 is a diagram illustrating an example of the overall configuration of the three-dimensional object forming apparatus 100.

As shown in FIG. 1, the three-dimensional modeling device 100 has a carrier belt 111, a modeling material supply unit 112, a flattening roller 113, a flying laser 115, a melting laser 116, a cleaning blade 117, and a collection case 118. It also has a modeling stage 301, a heater 302, and a control unit 400.

The three-dimensional modeling device 100 shoots the powdered modeling material 201 carried by the carrier belt 111 by irradiating it with the flying laser light 115a from the flying laser 115, causing it to land on the model 200 and form a modeling layer. The modeling layer is then heated, melted, and solidified to perform the modeling.

The modeling stage 301 is an example of a modeling table on which a three-dimensional object is modeled. The modeling stage 301 can move back and forth in the y-axis direction, and can also move up and down in the z-axis direction in increments of, for example, 0.1 mm for the modeling thickness. A heater 302 is provided below the modeling stage 301 (on the negative z-axis side), and the modeling stage 301 is configured to be temperature controllable in accordance with the modeling material 201.

The carrier belt 111 is an endless belt-like member capable of rotating while carrying the molding material 201. The carrier belt 111 is disposed above the molding stage 301 (on the positive z-axis side) and is supported by being wound around support rollers 133, 134, and 135.

At least one of the support rollers 133, 134, and 135 is a drive roller connected to a drive source such as a motor. As the drive roller rotates, the carrier belt 111 runs in a circular motion along the running direction 110 indicated by the arrow. The support rollers 133, 134, and 135 other than the drive roller are driven rollers, and rotate in response to the rotation of the carrier belt 111.

The carrier belt 111 can be made of, for example, a PET (Poly Ethylene Terephthalate) film, but is not limited to this and can also be made of a resin such as a polyimide film or a glass film.

In this embodiment, the support belt 111 supports the modeling material 201 mainly by van der Waals forces. If the resistance of the modeling material 201 is high, it can be supported by electrostatic adhesion alone.

The forming material supply unit 112 has a carrier roller 121, a supply roller 122, and a regulating blade 123, and supplies the forming material 201 stored in the forming material supply unit 112 to the carrier belt 111. The forming material supply unit 112 is arranged around the carrier belt 111.

The supply roller 122 is a roller that supplies the modeling material 201 stored in the modeling material supply unit 112 to the carrying roller 121. The carrying roller 121 is a roller that carries the modeling material 201 on its circumferential surface and transfers it to the carrier belt 111. The regulating blade 123 rubs the modeling material 201 carried on the circumferential surface of the carrying roller 121 to break up the agglomerations of the modeling material 201, thereby forming a thin layer of the modeling material 201 on the circumferential surface of the carrying roller 121.

The forming material supply unit 112 can supply the forming material 201 to the carrier belt 111 by contacting the forming material 201 on the peripheral surface of the carrier roller 121 with the carrier belt 111.

The molding material 201 should be appropriately selected depending on the desired three-dimensional object. In the case of resin, examples include amorphous resins such as PC (polycarbonate), ABS (acrylonitrile butadiene styrene), and PEI (polyetherimide), and crystalline resins such as PA12 (polyamide 12), PBT (polybutylene terephthalate), PSU (polysulfone), PA66 (polyamide 66), PET (polyethylene terephthalate), LCP (liquid crystal polymer), PEEK (polyether ether ketone), POM (polyacetal), PSF (polysulfone), PA6 (polyamide 6), and PPS (polyphenylene sulfide).

In addition to resin, the molding material 201 can be made of various materials such as metal, ceramic, and liquid.

The flying laser 115 is an example of a flying unit that is disposed inside the carrier belt 111 and irradiates the carrier belt 111 from the inside with a pulsed flying laser light 115a, causing the modeling material 201 carried by the carrier belt 111 to fly and land on a first area on the modeling stage 301. Here, the first area is an area where the flying modeling material 201 is to land, and is a predetermined area.

Although not shown in FIG. 1, the flight laser 115 has an optical scanning unit such as a galvanometer mirror. The optical scanning unit scans the flight laser light 115a in the x-axis direction by changing the angle of the mirror that reflects the flight laser light 115a. The flight laser 115 can selectively irradiate the flight laser light 115a to a predetermined position in the x-axis direction while changing the irradiation position of the flight laser light 115a using the optical scanning unit.

When the modeling material 201 is irradiated with the flying laser light 115a, the adhesive force of the modeling material 201 is released and the modeling material falls downward (negative direction of the z-axis). A previously known document (Flying phenomenon of single polymeric microparticles caused by laser pulses, Fukumoto et al. 1997) presumes that the flying mechanism occurs when the laser causes local expansion and the center of gravity moves instantaneously.

Laser transfer LIFT (Laser Induced Forward Transfer) described in US006025110A etc. is a method of non-contact transfer of foil-like or liquid material adhered to a carrier by laser irradiation. The material is locally heated and vaporized, and flies from the surface of the carrier belt 111 along the irradiation direction of the flying laser light 115a.

Pulse laser light can impart high energy instantaneously, and unlike CW (Continuous Wave) laser light, it can be made to fly without heating and melting the entire material, making it suitable as a laser light for flying the modeling material 201.

There are no particular limitations on the laser light source for the flight laser 115, and any laser capable of pulse oscillation from picoseconds to microseconds can be used. Solid-state lasers include YAG lasers and titanium sapphire lasers. Gas lasers include argon lasers, helium neon lasers, and carbon dioxide lasers. Semiconductor lasers are also preferable because they are small in size. The wavelength of the laser can be selected as appropriate, but is preferably 300 nm or more and 11 μm or less.

The modeling material 201 is sent flying by the flying laser light 115a, and a modeling layer is formed on the modeling stage 301 or the model 200 by accumulating the modeling material 201.

The flattening roller 113 is an example of a flattening mechanism that flattens the surface (the surface on the positive z-axis direction side) of the modeling layer formed by the modeling material 201 in the second region. The flattening roller 113 is disposed above the modeling stage 301.

The surface of the model 200 is in a state where the modeling material 201 flown by the flying laser light 115a has accumulated to form a modeling layer, but due to variations in flight, etc., the surface of the modeling layer may become uneven and not flat. The flattening roller 113 presses and moves excess modeling material above a predetermined height, scraping off the surface of the modeling layer to make it flat. The flattening roller 113 is fixed at a predetermined position, and as the modeling stage 301 moves in the positive y-axis direction, the excess modeling material is pressed against the flattening roller 113 and moves relatively in the negative y-axis direction.

The flattening roller 113 is included in a support forming section 114 that forms a support for supporting the molding material 201 in the second region around the second region using excess molding material. The flattening roller 113 is also an example of a moving section that moves the excess molding material in the second region around the second region. The flattening roller 113 can move the excess molding material on the surface of the molding layer formed by the molding material 201 in the second region around the second region.

The melting laser 116 is an example of a heating unit that heats the modeling material in the second region within the first region. The melting laser 116 does not need to actively use pulsed light, and a continuous wave laser is suitable. The melting laser 116 heats the surface of the model 200 being modeled on the modeling stage 301 to create a molten state. It is sufficient that the surface is brought into a molten state by the energy of one or more energy imparting means, and in addition to heating by laser, convection, lamp, induction heating, dielectric heating, etc. can also be applied.

The surface of the molded object 200 may be the surface of the molded object 200 for each modeling layer, or the surface of the molded object 200 for each of multiple modeling layers, such as two or three layers. Also, it may be a part of each layer or the entirety. In other words, it is important that a part of the outermost layer is included.

The irradiation positions of the melting laser light 116a from the melting laser 116 and the flying laser light 115a from the flying laser 115 can be adjusted, and the adjustment positions can be switched depending on the material type, modeling speed, etc. If the distance between the two is large, the modeling time will be long, so it is desirable for the distance to be close.

The cleaning blade 117 is disposed around the carrier belt 111 downstream in the running direction of the carrier belt 111 from the area where the model 200 is formed, and removes the modeling material 201 remaining on the carrier belt 111. The modeling material 201 scraped off by the cleaning blade 117 is collected in a collection case 118.

The control unit 400 is configured with electric circuits and realizes various functions described below in FIG. 2. Some of the functions can be realized by software (CPU; Central Processing Unit), and can also be realized by multiple circuits or multiple pieces of software. There are no particular restrictions on the placement location of the control unit 400, and it can be selected as appropriate.

<Example of functional configuration of control unit 400>
Next, the functional configuration of the control unit 400 will be described with reference to Fig. 2. Fig. 2 is a block diagram for explaining an example of the functional configuration of the control unit 400. Note that Fig. 2 shows only the main elements in the functional configuration of the control unit 400 for ease of understanding. As shown in Fig. 2, the control unit 400 has a region determination unit 401, a stage control unit 402, and a laser control unit 403.

Here, the modeling material 201 that is jetted by the jetting laser light 115a lands on the modeling stage 301 or on the modeled object 200, but the landing position may vary. Therefore, it is preferable to determine the first area that corresponds to the landing area of the modeling material 201 taking this landing variation into account.

When the landing variation is smaller than the required modeling accuracy, the second region, which is the region heated by the melting laser 116, and the first region may be the same region. However, when the landing variation is larger than the required modeling accuracy, it is preferable to make the first region larger than the second region in order to reduce the effect of the landing variation.

On the other hand, if the first region is made larger than the second region, surplus modeling material is generated around the second region that is not used as a part of the three-dimensional object. In the embodiment, this surplus modeling material around the second region is reused as a support for supporting the modeling material 201 in the object 200.

For example, without a support, the forming material 201 newly deposited on the object 200 tends to fall off the edge of the object 200 and move from the target position. The support prevents the forming material 201 from falling by supporting the forming material 201. In addition, if the object 200 includes an overhanging portion (protruding portion), the support also has the function of supporting the overhanging portion.

In the embodiment, the excess modeling material moved to the periphery of the second region by the flattening roller 113 (see FIG. 1) is also reused as a support. At this time, the flattening roller 113 moves the excess modeling material toward one of the four surrounding regions around the second region, so there may be a large amount of excess modeling material only in that surrounding region.

Therefore, in the embodiment, the area of the surrounding area on all four sides of the second region to which the excess molding material is moved is made smaller in advance compared to the other three surrounding areas, so that the amount of excess molding material is reduced. This makes it possible to equalize the amount of excess molding material in the surrounding areas on all four sides of the second region when the excess molding material is moved by the flattening roller 113.

As described above, the area determination unit 401 determines the first area based on the required modeling accuracy, the amount of excess modeling material required to function as a support, and the direction in which the excess modeling material is moved by the flattening roller 113. Then, information on the determined first area is provided to the stage control unit 402 and the laser control unit 403.

Here, the region determination unit 401 corresponds to the region determination unit included in the support formation unit 114 (see FIG. 1) that determines the first region. In other words, in this embodiment, the support formation unit 114 is configured to include the flattening roller 113 and the region determination unit 401.

The stage control unit 402 controls the modeling stage 301 based on the information of the first region, and the laser control unit 403 controls the irradiation of the flight laser light 115a by the flight laser 115. This makes it possible to fly the modeling material 201 and land the modeling material 201 in the first region.

<Operation Example of 3D Modeling Apparatus 100>
Next, the operation of the three-dimensional object forming apparatus 100 will be described.

(Overall operation example)
First, the overall operation of the 3D modeling apparatus 100 will be described with reference to Fig. 3. Fig. 3 is a flow chart for explaining an example of the overall operation of the 3D modeling apparatus 100. The description will also refer to the configuration diagram of Fig. 1 as necessary.

In step S31, the flying laser 115 irradiates the carrier belt 111 with the flying laser light 115a, causing the modeling material 201 carried by the carrier belt 111 to fly. The flying modeling material 201 lands on the modeling stage 301 or the modeled object 200, and a modeling layer is formed in the first region.

Next, in step S32, the modeling stage 301 moves in the positive direction of the y-axis, and the flattening roller 113 presses against the surface of the modeling layer to relatively move the excess modeling material in the negative direction of the y-axis. This flattens the surface of the modeling layer.

Next, in step S33, the melting laser 116 irradiates the melting laser light 116a to heat the second region within the first region. The modeling material 201 in the second region is melted by heating and is fixed onto the modeling stage 301 or the modeled object 200.

Next, in step S34, the three-dimensional modeling device 100 determines whether the model 200 has reached a predetermined height.

If it is determined in step S34 that the threshold has been reached (Yes in step S34), the operation ends. On the other hand, if it is determined that the threshold has not been reached (No in step S34), the operation returns to step S31, and the processing from step S31 onwards is repeated.

In this way, a three-dimensional object can be created.

(Example of operation of the flattening mechanism)
Next, the operation of the flattening mechanism will be described with reference to Fig. 4. Fig. 4 is a diagram for explaining an example of the operation of the flattening mechanism, in which (a) is a diagram showing an example of the operation of the flattening roller 113, and (b) is a diagram showing an example of the operation of the flattening blade.

As shown in FIG. 4(a), the flattening roller 113 contacts the surface on the positive z-axis side of the modeling layer 202 formed by the modeling material that has landed on the modeling stage 301 or the model 200 at a predetermined height relative to the modeling stage 301.

By moving the modeling stage 301 in the positive y-axis direction, the excess modeling material 203 on the surface of the modeling layer 202 can be moved relatively in the negative y-axis direction, so as to scrape off the surface of the modeling layer 202.

The rotation axis of the flattening roller 113 is fixed, and at the point where it contacts the modeling layer 202, it rotates in a rotation direction 113' that is opposite to the movement direction (positive y-axis direction) of the modeling stage 301, thereby moving the excess modeling material 203.

The surface region of the model 200 in FIG. 4(a) corresponds to the second region, which is the region heated by the melting laser light. The excess modeling material 203 is moved by the flattening roller 113 to the peripheral region of the second region on the negative y-axis side of the model 200.

In this embodiment, the rotation axis of the flattening roller 113 is fixed, but the rotation axis of the flattening roller 113 can be movable in the y-axis direction. The rotation direction 113' of the flattening roller 113 may be rotated in the same direction as the movement direction of the modeling stage 301 at the point where the flattening roller 113 contacts the modeling layer 202.

As shown in FIG. 4(b), a flattening blade 113a can also be used as the flattening mechanism. The flattening blade 113a is a plate-like member having a tapered shape, and is fixed to the modeling stage 301 at a predetermined angle with respect to the direction of movement (positive y-axis direction).

As the modeling stage 301 moves, it is pressed against the surface of the modeling layer 202, and the excess modeling material 203 on the surface of the modeling layer 202 is moved relatively in the negative y-axis direction, so that it can be scraped off the surface of the modeling layer 202. The movement of the excess modeling material 203 is the same as that described in FIG. 4(a), so a duplicated description will be omitted.

(An example of the first region and the second region)
Next, the first region and the second region in the modeling layer will be described with reference to Fig. 5. Fig. 5 is a diagram illustrating an example of the first region and the second region, in which (a) is a diagram showing the first region, (b) is a cross-sectional view taken along the line A-A in (a), (c) is a diagram showing the second region, and (d) is a cross-sectional view taken along the line B-B in (c).

As shown in Figures 5(a) and (b), the first region 202' is equal to the region in which the modeling layer 202 is formed by the modeling material that has landed on the modeling stage 301. The first region 202' is determined by the region determination unit 401 based on the required modeling accuracy, the amount of excess modeling material required to function as a support, and the direction in which the excess modeling material is moved by the flattening roller 113.

As shown in Figures 5(c) and (d), the second region 200' corresponds to the region in the modeling layer 202 that is heated by the melting laser light. The region heated by the melting laser light constitutes the modeled object 200 after melting and solidifying due to heating, so the second region 200' and the region of the modeled object 200 are substantially the same region.

The modeling layer 202 melts when heated by the melting laser light, eliminating any gaps between the modeling materials that make up the modeling layer 202, causing it to shrink and become smaller in height (length in the z-axis direction) compared to the unheated area.

There is excess modeling material in the area surrounding the second region 200' in the modeling layer 202, but when the next modeling layer 202 is formed on the model 200 (on the positive z-axis side), this functions as a support 204 that prevents modeling material located at the edge of the modeling layer 202 from falling off the modeling layer, for example by rolling off the layer. The supports 204 are formed in the peripheral areas on all four sides of the model 200, and prevent modeling material from falling off each of the four edges.

(Example of Modeling Operation by Three-Dimensional Modeling Apparatus 100)
Next, a modeling operation by the three-dimensional modeling apparatus 100 will be described with reference to Fig. 6. Fig. 6 is a diagram for explaining an example of the modeling operation by the three-dimensional modeling apparatus 100, and Figs. 6(a) to 6(f) are diagrams for explaining a series of operations. Figs. 6(a) to 6(c) show the modeling operation of the first modeling layer, and Figs. 6(d) to 6(f) show the modeling operation of the second modeling layer.

As shown in FIG. 6(a), after the modeling layer 202 is formed, the surface of the modeling layer 202 (the surface on the positive z-axis side) is flattened by a flattening roller.

Next, as shown in FIG. 6(b), the excess modeling material on the surface of the modeling layer 202 moved by the flattening roller is moved along a moving direction 203a (an example of a predetermined direction) toward the negative y-axis side of the second region 200'. The support 204 is formed by this moved excess modeling material and the excess modeling material 203 (FIG. 6(a)) of the surrounding region that is provided in advance on the positive y-axis side of the second region 200'.

Here, the excess molding material 203 provided in the four peripheral regions of the second region 200' each functions as a support 204, but in the peripheral region on the negative y-axis side of the four peripheral regions, the excess molding material on the surface of the modeling layer 202 is moved by the flattening roller. Therefore, if an equal amount of excess molding material 203 is provided in advance in the four peripheral regions, the amount of excess molding material may be greater only in the peripheral region on the negative y-axis side.

Therefore, as shown in FIG. 6(a), the width Y2 of the peripheral region on the negative y-axis side is smaller than the width Y1 of the peripheral region on the other side of the negative y-axis (Y2<Y1). In other words, the width Y2 of the peripheral region on the negative y-axis side is determined based on the direction in which the excess molding material is moved by the flattening roller, and the width of the first region 202' is also determined.

This ensures that when the flattening roller removes excess modeling material from the surface of the modeling layer 202, the amount of excess modeling material in the surrounding areas on all four sides is even.

Next, as shown in FIG. 6(c), the second region 200' is heated, melted, and solidified to form the object 200 from the first modeling layer.

Next, as shown in FIG. 6(d), a second modeling layer 202 is formed on the model 200, and as shown in FIG. 6(e), the surface of the second modeling layer 202 is flattened by a flattening roller, and a support 204 is formed in the peripheral region of the second region 200'. Note that the interface 204a (indicated by a thick line) in FIG. 6(d) is the interface between the support 204 and the second modeling layer.

Then, as shown in FIG. 6(f), the second region 200' is heated, melted, and solidified to form the object 200 from the first and second modeling layers.

The operations shown in Figures 6(d) to (f) are repeated to form and shape each modeling layer.

Here, since there is variation in the landing of the modeling material as it flies, the height of the modeling layer 202 may vary, resulting in reduced modeling accuracy.

To avoid this, it is possible to adjust the area and height (thickness) of the modeling layer 202 according to the variation in the height of the modeling layer 202 estimated based on the shape of the three-dimensional object, but if the variation becomes large, it may become difficult to make the adjustment.

In contrast, in this embodiment, the modeling layer is flattened by a flattening roller before being heated by the melting laser light, so that the surface of the modeling layer is always flattened before heating, and modeling precision can be maintained.

<Examples of determining the first area>
Next, various examples of how the first region is determined by the region determining unit 401 (see FIG. 2) will be described with reference to FIGS.

The support formed from the surplus modeling material may collapse if it becomes too tall as the model is being created. When it collapses, it is preferable to allow it to collapse while maintaining the angle of repose according to the properties of the modeling material that makes up the support and the deposition conditions. Here, the angle of repose refers to the angle between the slope of the mountain of modeling material being formed and the horizontal plane to prevent collapse and maintain stability when the modeling material is dropped from a certain height and deposited.

Figure 7 is a diagram explaining such an angle of repose, and is a cross-sectional view of the model 200 and the support 204. The angle between the inclined surface of the support 204 and the horizontal plane in Figure 7 corresponds to the angle of repose θ.

As shown in FIG. 7, it is preferable that the sides of the model 200 are supported by the supports 204 up to the height of the top surface. Since the excess modeling material that is moved when flattening the modeling layer also constitutes the supports 204, it is preferable that the first region for the target model is determined taking into account the angle of repose and the amount of excess modeling material.

Here, FIG. 8 is a diagram explaining an example of determining the first region, where (a) is a diagram showing the first example, (b) is a cross-sectional view taken along the arrows C-C of (a), (c) is a diagram showing a second example, (d) is a cross-sectional view taken along the arrows D-D of (c), (e) is a diagram showing a third example, and (f) is a cross-sectional view taken along the arrows E-E of (e). Also, FIG. 9 is a diagram showing a fourth example of determining the first region.

As shown in Figure 8(a), the target dimensions of the object are width X0 in the x-axis direction, width Y0 in the y-axis direction, and height Z0 in the z-axis direction, the difference in width between the first and second regions in the x-axis direction is X1+X2, and the difference in width between the first and second regions in the y-axis direction is Y1+Y2. Also, as shown in Figure 8(f), the target difference in the y-axis direction between the support 204 on the top surface (positive z-axis direction) side and the object 200 is Y4, and the bottom surface (positive z-axis direction) side is Y3.

As shown in Figures 8(c) and (d), the excess molding material 203 is moved toward the negative y-axis side to function as supporting powder that supports the surface of the model 200 on the negative y-axis side, but by making the width Y2 smaller than the width Y1, the amount of molding material used can be reduced.

The difference Y4 is preferably determined taking into consideration the variation in landing of the molding material. For example, a value of about 0.1 to 1 mm is preferable. The angle of repose θ is roughly calculated by the following formula.
θ=tan ^-1 {Z0/(Y3-Y4)}

Assuming that the volume of the surplus molding material is preserved between the side view of FIG. 8( d ) and the side view of FIG. 8( f ), the width Y1 is roughly a value calculated by the following formula.
Y1=√{(Y3 ² +Y3・Y4+Y4 ² )/3}
Similarly, the lengths X1 and X2 may be such that X1=X2=Y1.

Furthermore, during planarization, the thickness of the molding material removed from the surface (positive z-axis side) of the molding layer 202 is δZ (see FIG. 4(a)), the number of layers is N, α = N δZ/Z0, and the ratio of the height before and after the powder layer is heated and melted is β (based on the height after heating). Similarly, assuming that the volume of excess molding material is preserved between the side views of FIG. 8(b) and FIG. 8(d), the width Y2 can be calculated by the following formula.
Y2=(-α)・Y0/(α+β)+Y1・{2/(α+β)-1}

If width Y2 is less than 0, this means that there is too much excess molding material compared to the amount needed for the support, so Y2 = 0 should be set.

In this embodiment, the example shows the case where planarization is performed for each modeling layer, but if M modeling layers are formed and planarization is performed each time they are heated, the calculation can be made as α = N δZ/(M Z0).

In particular, since the support does not lose height due to heating or melting, excess molding material on the support increases, and the amount of support tends to be more than necessary. Therefore, during modeling, it is preferable to combine a layer in which the area in FIG. 8(a) becomes the first area 202' with a layer in which the area narrowed to a slightly wider area than the second area 200' becomes the first area 202' as shown in FIG. 9.

The widths X5 and Y5 in FIG. 9 are preferably determined taking into consideration the landing variation, similar to the width Y4. For example, a width of about 0.1 to 1 mm is suitable.

If the ratio of the number of layers that form the first region as shown in FIG. 8A to the total number of layers is γ, and the number of layers that form the region as shown in FIG. 9 is 1-γ, then the width Y2 can be calculated by the following formula.
Y2=(-α)・Y0/{(α+β)・γ}+{2/{(α+β)・γ}-1}・Y1

The width Y5 is very small, so it is ignored in this calculation. It is preferable that γ>1/(α+β) so that the height of the support is not insufficient. If the calculation yields Y2<0, then Y2=0 should be used.

We have explained how to estimate each parameter above, but as variations will occur due to factors such as collapse of the modeling layers, it is advisable to use values with some margin of error.

<Functions and Effects of the 3D Modeling Apparatus 100>
As described above, in this embodiment, the molding material is ejected and lands on a first region on the modeling table, the molding material in a second region within the first region is heated, and a support body for supporting the molding material in the second region is formed around the second region using surplus molding material.

For example, the first region that encompasses the second region is determined based on the required modeling accuracy or the amount of excess modeling material required to function as a support, and the excess modeling material is used to form a support around the second region.

Alternatively, the excess molding material is moved around the second region by a moving part such as a flattening roller, so that the excess molding material forms a support around the second region.

In order to reuse the surplus modeling material as a modeling material, a means for recovering the surplus modeling material is required, which may result in a complicated device.

By reusing the excess modeling material as a support at the same time (in parallel) as the flattening of the modeling layer, modeling can be performed while reusing the excess modeling material in a simple manner. Furthermore, by reusing the excess modeling material, waste of modeling material can be reduced.

In addition, in this embodiment, the first region is determined according to a predetermined direction (movement direction 203a) in which the surplus modeling material is moved by the moving unit. More specifically, the first region is determined such that the amount of surplus modeling material in the surrounding region in the predetermined direction among the four surrounding regions of the second region is less than the amount of surplus modeling material in the surrounding region in a direction other than the predetermined direction. This makes it possible to equalize the amount of surplus modeling material in the surrounding regions on all four sides of the second region, and to obtain the effect of the support body evenly.

In addition, this embodiment has a flattening mechanism that flattens the surface of the modeling layer, and flattens the modeling layer with a flattening roller before heating with the melting laser light. This ensures that the surface of the modeling layer is flattened before heating, and modeling precision can be maintained.

[Second embodiment]
Next, a three-dimensional object forming apparatus 100a according to a second embodiment will be described. Note that the same components as those described in the embodiment will be given the same part numbers, and duplicated descriptions will be omitted as appropriate.

<Overall configuration example of 3D object formation apparatus 100a>
10 is a diagram illustrating an example of the overall configuration of the 3D object forming apparatus 100a. As illustrated in FIG. 10, the 3D object forming apparatus 100a includes a carrier film 111a, a feed roll 111A, a take-up roll 111B, a forming material supply unit 112a, a flattening roller 113b, and a reflector 119.

The carrier film 111a is a film-like carrier that is disposed above the modeling stage 301 (on the positive z-axis side) and carries and transports the modeling material 201. The carrier film 111a is supported by multiple rollers including a pay-out roll 111A and a take-up roll 111B. The carrier film 111a can be a resin film containing polyimide, polycarbonate, polyvinylidene fluoride, etc.

By being wound from the pay-out roll 111A onto the take-up roll 111B, the carrier film 111a travels along the travel direction 110, and the supported modeling material 201 is transported above the modeling object 200 to be modeled on the modeling stage 301.

The forming material supply unit 112a is disposed around the carrier film 111a and supplies the forming material 201 to the surface of the carrier film 111a. The forming material supply unit 112a has a mesh roller 121a into which the forming material 201 is supplied and which rotates in the direction of the arrow, and a blade 123a which rubs the forming material 201 within the mesh roller 121a. The forming material supply unit 112a rubs the forming material 201 with the blade 123a to break up the agglomerations, allowing it to pass through the mesh roller 121a and forming a thin layer of the forming material 201 on the peripheral surface of the carrier film 111a.

The mesh openings of the mesh roller 121a are preferably 20 to 30% larger than the average particle size of the shaping material 201. A woven metal wire can be used, but a flat mesh made by electroforming or the like is more preferable. The contact method of the blade 123a can be selected as appropriate, either by trailing or by other contact methods such as a counter. The shaping material 201 can become clogged in the mesh openings, but clogging can be eliminated by contacting the mesh roller from the outer periphery with a brush made of fibers thinner than the openings.

The reflector 119 can deflect the melting laser light 116a. A reflector mirror made of a dielectric multilayer film can be used as the reflector 119.

The flattening roller 113b is configured to be able to move back and forth in the y-axis direction. Here, FIG. 11 is a diagram explaining an example of the operation of the flattening roller 113b, where (a) is a diagram showing a first example, and (b) is a diagram showing a second example.

In the example shown in FIG. 11(a), the flattening roller 113b is arranged so that the roller axis is aligned along the x-axis direction. After the formation of the modeling layer 202 by the flying of the modeling material is completed, the modeling stage 301 is moved in a moving direction 113d along the positive direction of the y-axis, and the modeling layer 202 is moved to a position where it does not interfere with the carrier film 111a or the irradiation position of the melting laser light, and then stopped.

Next, the modeling stage 301 is raised in the z-axis direction so that the distance between the modeling stage 301 and the flattening roller 113b in the z-axis direction becomes a predetermined value. In this state, the flattening roller 113b is moved in the negative z-axis direction and brought into contact with the surface of the modeling layer 202 to smooth out and flatten it. After flattening is complete, the modeling stage 301 is lowered to a predetermined height in the z-axis direction, and the modeling stage 301 is moved in the negative y-axis direction. After that, heating is performed using a melting laser.

In the example shown in FIG. 11(b), the flattening roller 113b is arranged so that the roller axis of the flattening roller 113b is inclined with respect to the moving direction 113d of the modeling stage 301 in the xy plane, which is a plane including the modeling layer 202. In this way, the excess modeling material can be moved not only in the y-axis direction but also in the x-axis direction.

It is more preferable to switch the direction of movement of the flattening roller 113b during flattening for each layer, as this can eliminate bias in the destination of the excess modeling material. Furthermore, if flattening is performed once after forming multiple modeling layers rather than flattening each layer, the modeling time can be shortened because flattening is not performed for each layer. Furthermore, the formation of the modeling layer 202 and the heating and melting of the modeling layer 202 can be repeated multiple times, and then flattening can be performed after the modeling layer 202 is formed. This can further shorten the modeling time.

In addition, a scraper or other configuration can be provided around the flattening roller 113b. Figure 12 is a diagram illustrating an example of the configuration around the flattening roller 113b. As shown in Figure 12, a scraper 140 and a surplus collection case 141 are provided around the flattening roller 113b.

The scraper 140 is provided at a predetermined cleaning position of the flattening roller 113b, and cleans the surface of the flattening roller 113b by scraping and removing excess molding material adhering to the surface of the flattening roller 113b that has been moved to the cleaning position.

The surplus collection case 141 is a case for collecting the surplus molding material removed by the scraper 140.

<Example of Modeling Operation by Three-Dimensional Modeling Apparatus 100a>
FIG. 13 is a flowchart illustrating an example of a modeling operation performed by the three-dimensional modeling apparatus 100a.

First, in step S131, the flying laser 115 irradiates the carrier film 111a with the flying laser light 115a, causing the modeling material 201 carried by the carrier film 111a to fly. The flying modeling material 201 lands on the modeling stage 301 or the modeled object 200, and a modeling layer is formed in the first region.

Next, in step S132, the three-dimensional modeling device 100a determines whether the number of modeling layers has reached the number of layers to be flattened.

If it is determined in step S132 that the limit has been reached (Yes in step S132), the operation proceeds to step S133. On the other hand, if it is determined that the limit has not been reached (No in step S132), the operation proceeds to step S134.

Next, in step S133, the modeling stage 301 moves in the positive y-axis direction and stops after reaching a position where flattening is performed. The flattening roller 113b then moves along the movement direction 113d, pressing against the surface of the modeling layer to move the excess modeling material. This causes the surface of the modeling layer to be flattened.

Next, in step S134, the melting laser 116 irradiates the melting laser light 116a to heat the second region within the first region on the surface of the modeling layer. The modeling material 201 in the second region is melted by heating and is fixed onto the modeling stage 301 or the modeled object 200.

Next, in step S135, the three-dimensional modeling device 100 determines whether the model 200 has reached a predetermined height.

If it is determined in step S135 that the threshold has been reached (Yes in step S135), the operation ends. On the other hand, if it is determined that the threshold has not been reached (No in step S135), the operation returns to step S131, and the processing from step S131 onwards is repeated.

In this way, a three-dimensional object can be created.

Although the preferred embodiments and examples of the present invention have been described in detail above, the present invention is not limited to these embodiments and examples, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

The embodiment can be applied to various modeling methods as long as the device is capable of stacking modeling layers, which are thin layers formed from a modeling material, to create a model.

In addition, all the numbers such as ordinal numbers and quantities used above are merely examples to specifically explain the technology of the present invention, and the present invention is not limited to the exemplified numbers. In addition, the connections between the components are merely examples to specifically explain the technology of the present invention, and the connections that realize the functions of the present invention are not limited to these.

The embodiment also includes a three-dimensional modeling method. For example, the three-dimensional modeling method is a three-dimensional modeling method using a three-dimensional modeling device that models a three-dimensional object on a modeling table, and includes the steps of: flying modeling material to land on a first region on the modeling table; heating the modeling material in a second region within the first region; and forming a support for supporting the modeling material in the second region around the second region using surplus modeling material. This three-dimensional modeling method can achieve the same effects as the three-dimensional modeling device described above.

100 Three-dimensional object forming apparatus 111 Support belt 111a Support film 111A Pay-out roll 111B Take-up roll 112 Forming material supply unit 113 Flattening roller (an example of a moving part, an example of a flattening mechanism)
114 Support forming section 115 Laser for flying (an example of a flying section)
115a: Laser light for flying 116: Laser for melting (an example of a heating unit)
Reference Signs: 116a: melting laser beam 117: cleaning blade 118: collection case 119: reflector 140: scraper 141: surplus collection case 200: model 200': second region 201: modeling material 202: modeling layer 202': first region 203: surplus modeling material 204: support 301: modeling stage 302: heater 400: control unit 401: region determination unit 402: stage control unit 403: laser control unit θ: angle of repose

Patent No. 6380948

Claims (6)

A three-dimensional modeling apparatus that forms a three-dimensional object on a modeling table, comprising:
a flying unit that shoots a powder-like molding material and makes it land on a first region on the molding table;
a heating section that heats the shaping material in a second region within the first region;
a support forming unit that forms a support that supports the molding material in the second region around the second region using surplus molding material ,
The support forming section includes:
A region determining unit that determines the first region;
a moving unit that moves the surplus molding material in the second region to a periphery of the second region,
the moving unit moves the surplus molding material in the second area in a predetermined direction,
The region determining unit determines the first region according to the predetermined direction.
3D modeling device. 2. The three-dimensional modeling apparatus according to claim 1, wherein the region determination unit determines the first region such that an amount of surplus modeling material in the surrounding region of the second region in the specified direction is less than an amount of surplus modeling material in the surrounding region in a direction other than the specified direction. The three-dimensional object forming apparatus according to claim 1 , wherein the moving unit includes a flattening mechanism that flattens a surface of a modeling layer formed by the modeling material in the second region. The three-dimensional object fabrication apparatus according to claim 3 , wherein the planarization mechanism planarizes a surface of the modeling layer before the heating by the heating unit. The three-dimensional object forming apparatus according to claim 3 or 4 , wherein the planarization mechanism planarizes the surface of the object forming layer each time a plurality of object forming layers are stacked. A three-dimensional object forming method using a three-dimensional object forming apparatus for forming a three-dimensional object on a forming table, comprising the steps of:
a step of flying a powder-like modeling material by a flying unit to land on a first region on the modeling table;
heating the shaping material in a second region within the first region by a heating unit;
forming , by a support-forming unit, a support that supports the molding material in the second region, around the second region using surplus molding material ;
The support forming section includes:
A region determining unit determines the first region;
a moving unit moving the surplus molding material in the second region to a periphery of the second region;
the moving unit moves the surplus molding material in the second region in a predetermined direction,
The region determining unit determines the first region according to the predetermined direction.
Three-dimensional modeling method.

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