Patent Description:
In the related art, production methods for producing a three-dimensional shaped article by stacking layers have been performed. Among these, a production method in which a three-dimensional shaped article is produced while supporting a constituent layer which corresponds to a constituent region of a three-dimensional shaped article when forming the constituent layer has been disclosed.

For example, <CIT> (Patent Document <NUM>) discloses a production method in which a cycle including formation of a layer from a powder material and ejection of a binder onto a portion which corresponds to a constituent region of a three-dimensional shaped article (that is, a constituent layer) is performed a plurality of times, whereby a three-dimensional shaped article is produced while supporting the constituent layer by the powder material in a portion other than the portion which corresponds to the constituent region.

A three-dimensional shaped article can be constituted by any of various materials, and for example, the shape of a three-dimensional shaped article is formed from a metal, a ceramic, or the like, and after completion of the shape of the three-dimensional shaped article, the article is sintered in some cases. Among these, there is a case where the constituent layer of a three-dimensional shaped article is sintered by collectively heating the constituent layer and a support layer thereof. In such a case, the support layer plays a role in supporting the constituent layer during sintering, and also in order to facilitate the release of the support layer from the constituent layer after sintering, a support layer which has a small change in shape accompanying the sintering of the constituent layer and also is not melted or sintered accompanying the sintering of the constituent layer is generally used.

However, in the case where such a support layer is formed, in the production method of the related art in which a three-dimensional shaped article is produced while supporting the constituent layer of the three-dimensional shaped article when the constituent layer is formed, the change in the shape of the support layer does not follow the change in the volume (shrinkage) accompanying the sintering of the constituent layer, and therefore, the constituent layer is distorted (that is, the sintered body of the three-dimensional shaped article is deformed) in some cases. That is, a three-dimensional shaped article with high accuracy cannot be produced due to the distortion of the constituent layer in some cases.

<CIT> relates to an article that is produced using free-form fabrication having a binder matrix and particles that can be supported during a temperature processing, such as burn-out of the binder matrix, with a support composition to maintain geometry and/or alleviate changes in geometry of the article. The support composition can take a variety of forms such as foams, two phase materials, plastic powders, carbon powders, etc. The support material is sacrificed during the thermal processing, such as through decomposition. Such a decomposition can occur when the support composition evolves into a carbonaceous structure. The support composition can also oxidize to a gas, melt, or vaporize, among other types of sacrificial action.

<CIT> relates to a method for printing and supporting a three-dimensional object. The method of printing can include dispensing a first interface material for the construction of the three-dimensional object, dispensing a second interface material to form a support structure for supporting the three-dimensional object, and dispensing a third interface material which may be used to separate the support structure from the <NUM>-D object.

An advantage of some aspects of the invention is to produce a three-dimensional shaped article with high accuracy.

A three-dimensional shaped article production method according to a first aspect of the invention is a three-dimensional shaped article production method as defined in claim <NUM>.

According to this aspect of the invention, the support layer is configured such that as compared with the volume decrement during the sintering step of an internal space in the constituent layer, the volume decrement during the sintering step of the support layer which supports the constituent layer in the space is larger. That is, the shape of the support layer changes in response to the volume change (shrinkage) during the sintering of the constituent layer, and therefore, the support layer does not hinder the shrinkage during the sintering of the constituent layer. Due to this, the deformation of the sintered body of the three-dimensional shaped article can be suppressed, and thus, the three-dimensional shaped article with high accuracy can be produced.

Incidentally, the "volume decrement during the sintering step of an internal space in the constituent layer" refers to a volume decrement based on the constituent material of the constituent layer, and refers to a volume decrement after the sintering step of the space in the case where the support layer is not present in the space.

Further, the "internal space in the constituent layer" refers to an internal space whose volume decreases when the overall shape is isotropically shrunk such as an internal space having a bottomed or bottomless cylindrical shape or an internal space having a cup-like shape such that an opening portion is larger or smaller than a bottom portion.

According to the aspect of the invention, at least a portion of the support layer which supports the constituent layer in the space includes a first support material whose volume change during the sintering step is relatively large and a second support material whose volume change during the sintering step is relatively small. Due to this, the shape of the support layer changes in response to the volume change (shrinkage) during the sintering of the constituent layer effectively by the first support material whose volume change is relatively large, and the constituent layer during sintering can be supported efficiently by the second support material whose volume change is relatively small.

Incidentally, the "first support material whose volume change is relatively large and the second support material whose volume change is relatively small" are not particularly limited with respect to the difference thereof or the absolute amount thereof as long as the volume change ratio (shrinkage ratio) of the first support material whose volume change is large is larger than the volume change ratio (shrinkage ratio) of the second support material whose volume change is small, and also includes a case where there is substantially no volume change ratio (shrinkage ratio) in the second support material whose volume change is small.

Preferably, at least a portion of the support layer which supports the constituent layer in the space is structurally changed during the sintering step.

Due to this, by the structural change, the shape of the support layer changes in response to the volume change (shrinkage) during the sintering of the constituent layer, and therefore, the hindrance of the support layer to shrinkage during the sintering of the constituent layer can be effectively suppressed.

Incidentally, the "structural change during the sintering step" includes, for example, a configuration in which a portion of the support layer forming material is decomposed and removed, and other than this, a configuration in which the structure of the support layer formed by a honeycomb structure, a truss structure, a lattice structure, or the like is collapsed during the sintering step, and the like.

Preferably, at least a portion of the support layer which supports the constituent layer in the space is powdered during the sintering step.

Due to this, after the sintering step, the sintered body of the three-dimensional shaped article can be easily taken out from the support layer (the support layer can be easily removed from the sintered body of the three-dimensional shaped article).

Preferably, at least a portion of the support layer which supports the constituent layer in the space is volatilized during the sintering step.

Due to this, by performing a step of removing a gas containing the volatilized component during the sintering step or after the sintering step, the support layer can be easily removed from the sintered body of the three-dimensional shaped article.

Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, wherein like numbers reference like elements.

Hereinafter, embodiments according to the invention will be described with reference to the accompanying drawings.

<FIG> are schematic configuration views showing a configuration of a three-dimensional shaped article production apparatus according to an embodiment of the invention.

Here, the three-dimensional shaped article production apparatus according to this embodiment includes two material supply sections (head bases) and two solidification sections. Among these, <FIG> are views showing only one material supply section (a material supply section which supplies a constituent material (a material containing a powder constituting a three-dimensional shaped article, a solvent, and a binder)). <FIG> are views of the same apparatus showing another material supply section (a material supply section which supplies a support layer forming material for forming a support layer that supports a three-dimensional shaped article when the three-dimensional shaped article is formed) and two solidification sections (a curing section using an electromagnetic wave for curing the support layer forming material and a heating section using a laser for sintering the support layer forming material).

The "three-dimensional shaping" as used herein refers to the formation of a so-called "three-dimensional shaped article", and also includes, for example, the formation of a shape with a thickness even if the shape is a plate shape or a so-called two-dimensional shape. Further, the "supporting" as used herein includes supporting from the lower side, and in addition thereto, also includes supporting from the lateral side, and in some cases, supporting from the upper side.

A three-dimensional shaped article production apparatus <NUM> (hereinafter referred to as "forming apparatus <NUM>") shown in <FIG> includes a base <NUM> and a stage <NUM> which is provided movably in the X, Y, and Z directions shown in the drawing or drivably in the direction of rotation about the Z axis by a drive device <NUM> as a drive unit provided for the base <NUM>.

Then, as shown in <FIG>, the forming apparatus <NUM> includes a head base support section <NUM>, one end of which is fixed to the base <NUM>, and to the other end of which, a head base <NUM> that holds a plurality of head units <NUM> each including a constituent material ejection section <NUM> that ejects a constituent material is held and fixed.

Further, as shown in <FIG>, the forming apparatus <NUM> includes a head base support section <NUM>, one end of which is fixed to the base <NUM>, and to the other end of which, a head base <NUM> that holds a plurality of head units <NUM> each including a support layer forming material ejection section <NUM> that ejects a material for forming a support layer that supports a three-dimensional shaped article is held and fixed.

Here, the head base <NUM> and the head base <NUM> are provided in parallel in the XY plane.

The constituent material ejection section <NUM> and the support layer forming material ejection section <NUM> have the same configuration. However, the configuration is not limited thereto.

On the stage <NUM>, layers <NUM>, <NUM>, and <NUM> are formed in the process for forming a three-dimensional shaped article <NUM>. In the formation of the three-dimensional shaped article <NUM>, thermal energy is applied by a laser or the like, and therefore, in order to protect the stage <NUM> from heat, by using a sample plate <NUM> having heat resistance, the three-dimensional shaped article <NUM> may be formed on the sample plate <NUM>. The sample plate <NUM> of this embodiment is made of a metal so that it is sturdy and is easily produced. However, as the sample plate <NUM>, for example, by using a ceramic plate, high heat resistance can be obtained, and also the reactivity with the constituent material of the three-dimensional shaped article to be melted (or which may be sintered) is low, and thus, alteration of the three-dimensional shaped article <NUM> can be prevented. Incidentally, in <FIG> and <FIG>, for the sake of convenience of explanation, three layers: the layers <NUM>, <NUM>, and <NUM> are shown as examples, however, the layers (up to the layer 50n in <FIG> and <FIG>) are stacked until the desired shape of the three-dimensional shaped article <NUM> is obtained.

Here, the layers <NUM>, <NUM>, <NUM>,. , and 50n are each constituted by a support layer <NUM> formed from the support layer forming material ejected from the support layer forming material ejection section <NUM> and a constituent layer <NUM> formed from the constituent material ejected from the constituent material ejection section <NUM>.

<FIG> is an enlarged conceptual view of a portion C showing the head base <NUM> shown in <FIG>. As shown in <FIG>, the head base <NUM> holds a plurality of head units <NUM>. Although a detailed description will be given later, each head unit <NUM> is configured such that the constituent material ejection section <NUM> included in a constituent material supply device <NUM> is held by a holding jig 1400a. The constituent material ejection section <NUM> includes an ejection nozzle 1230a and an ejection drive section 1230b that allows the constituent material to be ejected from the ejection nozzle 1230a by a material supply controller <NUM>.

<FIG> is an enlarged conceptual view of a portion C' showing the head base <NUM> shown in <FIG>. As shown in <FIG>, the head base <NUM> holds a plurality of head units <NUM>. Each head unit <NUM> is configured such that the support layer forming material ejection section <NUM> included in a support layer forming material supply device <NUM> is held by a holding jig 1900a. The support layer forming material ejection section <NUM> includes an ejection nozzle 1730a and an ejection drive section 1730b that allows the support layer forming material to be ejected from the ejection nozzle 1730a by the material supply controller <NUM>. Further, the head base <NUM> is provided with an electromagnetic wave irradiation section <NUM> for curing the support layer forming material in the case where a material which can be cured by an electromagnetic wave (such as an ultraviolet ray) is used as the support layer forming material. In addition, in the case where a material which can be dissolved in a solvent is used as a binder to be contained in the support layer forming material, the head base <NUM> may be provided with an electromagnetic wave (infrared ray) irradiation section <NUM> for removing the solvent and curing the support layer forming material (binding with the binder). Further, in the case where a material which can be sintered is used as the support layer forming material, a laser irradiation section <NUM> for sintering the support layer forming material and a galvanometer mirror <NUM> which determines the position of the laser light from the laser irradiation section <NUM> are provided on the upper side of the stage <NUM>.

As shown in <FIG>, the constituent material ejection section <NUM> is connected to a constituent material supply unit <NUM> which houses a constituent material made to correspond to each head unit <NUM> held by the head base <NUM> through a supply tube <NUM>. Then, a given constituent material is supplied to the constituent material ejection section <NUM> from the constituent material supply unit <NUM>. In the constituent material supply unit <NUM>, the constituent material of the three-dimensional shaped article <NUM> to be shaped by the forming apparatus <NUM> according to this embodiment is housed in a constituent material housing section 1210a, and each individual constituent material housing section 1210a is connected to each (or a corresponding one or more) individual constituent material ejection section(s) <NUM> through the supply tube <NUM>. In this manner, by including the individual constituent material housing sections 1210a, a plurality of different types of materials can be supplied from the head base <NUM>.

As shown in <FIG>, the support layer forming material ejection section <NUM> is connected to a support layer forming material supply unit <NUM> which houses a support layer forming material made to correspond to each head unit <NUM> held by the head base <NUM> through a supply tube <NUM>. Then, a given support layer forming material is supplied to the support layer forming material ejection section <NUM> from the support layer forming material supply unit <NUM>. In the support layer forming material supply unit <NUM>, the support layer forming material constituting a support layer when shaping the three-dimensional shaped article <NUM> is housed in a support layer forming material housing section 1710a, and each individual support layer forming material housing section 1710a is connected to each (or a corresponding one or more) individual support layer forming material ejection section(s) <NUM> through the supply tube <NUM>. In this manner, by including the individual support layer forming material housing sections 1710a, a plurality of different types of support layer forming materials can be supplied from the head base <NUM>.

As the constituent material and the support layer forming material, for example, a simple substance powder of magnesium (Mg), iron (Fe), cobalt (Co), chromium (Cr), aluminum (Al), titanium (Ti), copper, (Cu), or nickel (Ni), or a mixed powder of an alloy containing at least one metal among these (a maraging steel, stainless steel, cobalt-chrome-molybdenum, a titanium alloy, a nickel alloy, an aluminum alloy, a cobalt alloy, or a cobalt-chromium alloy) or the like is prepared as a mixed material or the like in the form of a slurry (or a paste) containing a solvent and a binder.

It is also possible to use general purpose engineering plastics such as polyamide, polyacetal, polycarbonate, modified polyphenylene ether, polybutylene terephthalate, and polyethylene terephthalate. In addition thereto, it is also possible to use engineering plastics such as polysulfone, polyethersulfone, polyphenylene sulfide, polyarylate, polyimide, polyamideimide, polyetherimide, and polyether ether ketone.

In this manner, the constituent material and the support layer forming material are not particularly limited, and a metal other than the above-mentioned metals, a ceramic, a resin, or the like can also be used. Further, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, or the like can be preferably used.

Examples of the solvent include water; (poly)alkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether; acetate esters such as ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, and iso-butyl acetate; aromatic hydrocarbons such as benzene, toluene, and xylene; ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, ethyl n-butyl ketone, diisopropyl ketone, and acetyl acetone; alcohols such as ethanol, propanol, and butanol; tetra-alkyl ammonium acetates; sulfoxide-based solvents such as dimethyl sulfoxide and diethyl sulfoxide; pyridine-based solvents such as pyridine, γ-picoline, and <NUM>,<NUM>-lutidine; and ionic liquids such as tetra-alkyl ammonium acetate (for example, tetra-butyl ammonium acetate, etc.), and one type or two or more types in combination selected from these can be used.

As the binder, for example, an acrylic resin, an epoxy resin, a silicone resin, a cellulosic resin, or another synthetic resin, or PLA (polylactic acid), PA (polyamide), PPS (polyphenylene sulfide), or another thermoplastic resin can be used. Further, a UV curable resin which is polymerized by irradiation with an ultraviolet ray may be used as the binder.

The forming apparatus <NUM> includes a control unit <NUM> as a control device which controls the stage <NUM>, the constituent material ejection section <NUM> included in the constituent material supply device <NUM>, and the support layer forming material ejection section <NUM> included in the support layer forming material supply device <NUM> based on the data for shaping a three-dimensional shaped article to be output from a data output device such as, for example, a personal computer (not shown). The control unit <NUM> includes a control section (not shown) which controls the stage <NUM> and the constituent material ejection section <NUM> so that these members are driven and operated in cooperation with each other, and also controls the stage <NUM> and the support layer forming material ejection section <NUM> so that these members are driven and operated in cooperation with each other.

The stage <NUM> provided movably for the base <NUM>, and a signal for controlling the start and stop of movement, the direction of movement, the amount of movement, the speed of movement, or the like of the stage <NUM> is generated in a stage controller <NUM> based on a control signal from the control unit <NUM> and sent to the drive device <NUM> included in the base <NUM>, and the stage <NUM> moves in the X, Y, or Z direction shown in the drawing. In the constituent material ejection section <NUM> included in the head unit <NUM>, a signal for controlling the amount of the material ejected from the ejection nozzle 1230a by the ejection drive section 1230b included in the constituent material ejection section <NUM> or the like is generated in the material supply controller <NUM> based on a control signal from the control unit <NUM>, and a predetermined amount of the constituent material is ejected from the ejection nozzle 1230a based on the generated signal.

In the same manner, in the support layer forming material ejection section <NUM> included in the head unit <NUM>, a signal for controlling the amount of the material ejected from the ejection nozzle 1730a by the ejection drive section 1730b included in the support layer forming material ejection section <NUM> or the like is generated in the material supply controller <NUM> based on a control signal from the control unit <NUM>, and a predetermined amount of the support layer forming material is ejected from the ejection nozzle 1730a based on the generated signal.

Next, the head unit <NUM> will be described in further detail. The head unit <NUM> has the same configuration as that of the head unit <NUM>, and therefore, a detailed description of the configuration of the head unit <NUM> will be omitted.

<FIG> show one example of the holding form of a plurality of head units <NUM> and the constituent material ejection sections <NUM> held by the head base <NUM>, and among these, <FIG> are external views of the head base <NUM> viewed from the direction of the arrow D shown in <FIG>.

As shown in <FIG>, a plurality of head units <NUM> are held by the head base <NUM> through a fixing unit (not shown). Further, as shown in <FIG>, in the head base <NUM> of the forming apparatus <NUM> according to this embodiment, the head units <NUM> are included such that the following <NUM> units: a head unit <NUM> in the first row from the lower side in the drawing, a head unit <NUM> in the second row, a head unit <NUM> in the third row, and a head unit <NUM> in the fourth row are arranged in a staggered manner (alternately). Then, as shown in <FIG>, while moving the stage <NUM> in the X direction with respect to the head base <NUM>, the constituent material is ejected from each head unit <NUM>, whereby constituent layer constituting parts <NUM> (constituent layer constituting parts 50a, 50b, 50c, and 50d) are formed. The procedure for forming the constituent layer constituting parts <NUM> will be described later.

Incidentally, although not shown in the drawing, the constituent material ejection sections <NUM> included in the respective head units <NUM> to <NUM> are configured to be connected to the constituent material supply unit <NUM> through the ejection drive section 1230b with the supply tube <NUM>.

As shown in <FIG>, the constituent material ejection section <NUM> ejects a material M which is the constituent material of the three-dimensional shaped article from the ejection nozzle 1230a onto the sample plate <NUM> placed on the stage <NUM>. In the head unit <NUM>, an ejection form in which the material M is ejected in the form of a liquid droplet is illustrated, and in the head unit <NUM>, an ejection form in which the material M is supplied in the form of a continuous body is illustrated. The ejection form of the material M may be in the form of either a liquid droplet or a continuous body, however, in this embodiment, a case where a form in which the material M is ejected in the form of a liquid droplet is adopted will be described.

The material M ejected in the form of a liquid droplet from the ejection nozzle 1230a flies substantially in the direction of gravity and lands on the sample plate <NUM>. The stage <NUM> moves, and by the material M landing on the sample plate <NUM>, the constituent layer constituting parts <NUM> are formed. An assembly of the constituent layer constituting parts <NUM> is formed as the constituent layer <NUM> (see <FIG>) of the three-dimensional shaped article <NUM> formed on the sample plate <NUM>.

Next, the procedure for forming the constituent layer constituting parts <NUM> will be described with reference to <FIG>.

<FIG> are plan views conceptually illustrating the relationship between the arrangement of head units <NUM> of this embodiment and the form of formation of the constituent layer constituting parts <NUM>. <FIG> are side views conceptually illustrating the form of formation of the constituent layer constituting parts <NUM>.

First, when the stage <NUM> moves in the +X direction, the material M is ejected in the form of a liquid droplet from the plurality of ejection nozzles 1230a, and the material M is placed at a predetermined position on the sample plate <NUM>, and therefore, the constituent layer constituting parts <NUM> are formed.

More specifically, first, as shown in <FIG>, while moving the stage <NUM> in the +X direction, the material M is placed at predetermined positions at regular intervals on the sample plate <NUM> from the plurality of ejection nozzles 1230a.

Subsequently, as shown in <FIG>, while moving the stage <NUM> in the -X direction shown in <FIG>, the material M is newly placed so as to fill the gap between the materials M placed at regular intervals.

However, a configuration in which while moving the stage <NUM> in the +X direction, the materials M are ejected from the plurality of ejection nozzles 1230a so that the materials M overlap with each other (so as not to form a gap) at predetermined positions on the sample plate <NUM> (not a configuration in which the constituent layer constituting parts <NUM> are formed by the reciprocation of the stage <NUM> in the X direction, but a configuration in which the constituent layer constituting parts <NUM> are formed by only one way movement of the stage <NUM> in the X direction) may be adopted.

By forming the constituent layer constituting parts <NUM> as described above, the constituent layer constituting parts <NUM> (the constituent layer constituting parts 50a, 50b, 50c, and 50d) for one line (of the first line in the Y direction) in the X direction of the respective head units <NUM>, <NUM>, <NUM>, and <NUM> as shown in <FIG> are formed.

Subsequently, in order to form constituent layer constituting parts <NUM>' (constituent layer constituting parts 50a', 50b', 50c', and 50d') of the second line in the Y direction of the respective head units <NUM>, <NUM>, <NUM>, and <NUM>, the head base <NUM> is moved in the -Y direction. As for the amount of movement, when the pitch between the nozzles is represented by P, the head base <NUM> is moved in the -Y direction by a distance of P/n (n represents a natural number). In this embodiment, a description will be given by assuming that n is <NUM>.

By performing the same operation as described above as shown in <FIG>, the constituent layer constituting parts <NUM>' (constituent layer constituting parts 50a', 50b', 50c', and 50d') of the second line in the Y direction as shown in <FIG> are formed.

Subsequently, in order to form constituent layer constituting parts <NUM>" (constituent layer constituting parts 50a", 50b", 50c", and 50d") of the third line in the Y direction of the respective head units <NUM>, <NUM>, <NUM>, and <NUM>, the head base <NUM> is moved in the - Y direction. As for the amount of movement, the head base <NUM> is moved in the -Y direction by a distance of P/<NUM>.

Then, by performing the same operation as described above as shown in <FIG>, the constituent layer constituting parts <NUM>" (constituent layer constituting parts 50a", 50b", 50c", and 50d") of the third line in the Y direction as shown in <FIG> are formed, and thus, the constituent layer <NUM> can be obtained.

Further, as for the material M ejected from the constituent material ejection section <NUM>, from any one unit or two or more units of the head units <NUM>, <NUM>, <NUM>, and <NUM>, a constituent material different from the other head units can also be ejected and supplied. Therefore, by using the forming apparatus <NUM> according to this embodiment, a three-dimensional shaped article formed from different materials can also be obtained.

Incidentally, in the layer <NUM> as the first layer, by ejecting the support layer forming material from the support layer forming material ejection section <NUM> before, during or after forming the constituent layer <NUM> as described above, the support layer <NUM> can be formed in the same manner as described above. Then, also when forming the layers <NUM>, <NUM>,. , and 50n by being stacked on the layer <NUM>, the constituent layer <NUM> and the support layer <NUM> can be formed in the same manner as described above. The support layer <NUM> can be cured using the electromagnetic wave irradiation section <NUM>, or sintered using the laser irradiation section <NUM> and the galvanometer mirror <NUM>, or the like according to the type of the support layer forming material.

The number and arrangement of the head units <NUM> and <NUM> included in the forming apparatus <NUM> according to this embodiment described above are not limited to the above-mentioned number and arrangement. <FIG> schematically show examples of other arrangement of the head units <NUM> placed in the head base <NUM>.

<FIG> shows a form in which a plurality of head units <NUM> are arranged in parallel in the X-axis direction in the head base <NUM>. <FIG> shows a form in which the head units <NUM> are arranged in a lattice pattern in the head base <NUM>. The number of the head units to be arranged is not limited to the examples shown in <FIG> in either case.

Next, one embodiment of a three-dimensional shaped article production method to be performed using the above-mentioned forming apparatus <NUM> according to this embodiment will be described.

<FIG> are schematic views showing one example of a three-dimensional shaped article production process to be performed using the forming apparatus <NUM>. <FIG> show the three-dimensional shaped article production process in side view, and <FIG> show the three-dimensional shaped article production process in plan view. Further, 7E and 7F correspond to 7C and 7D, respectively.

First, <FIG> shows a state where the support layer <NUM> in the layer <NUM> as the first layer is formed on the sample plate <NUM> using the support layer forming material ejection section <NUM>. In this embodiment, as the support layer forming material, a material containing ceramic particles and a UV curable resin as the binder is used. As the support layer forming material, a material containing ceramic particles, a solvent, and a binder may be used.

Here, <FIG> shows a state where the support layer forming material is ejected from the support layer forming material ejection section <NUM> and also an electromagnetic wave is irradiated onto the support layer forming material from the electromagnetic wave irradiation section <NUM>.

Subsequently, <FIG> shows a state where the constituent layer <NUM> in the layer <NUM> as the first layer is formed on the sample plate <NUM> using the constituent material ejection section <NUM>. In this embodiment, as the constituent material, a material containing metal particles is used.

Then, by repeating the formation of the support layer <NUM> shown in <FIG> and the formation of the constituent layer <NUM> shown in <FIG>, a stacked body of the three-dimensional shaped article is formed as shown in <FIG>.

Here, as shown in <FIG>, the stacked body of the three-dimensional shaped article of this embodiment has a bottomless cylindrical shape, and a portion surrounded by the constituent layer <NUM> forms a space S (to be exact, a space S surrounded by the constituent layer <NUM> from at least two directions).

Then, finally, the stacked body of the three-dimensional shaped article formed as shown in <FIG> is heated in a high-temperature chamber (heating chamber) provided separately from the forming apparatus <NUM> according to this embodiment (the constituent layer <NUM> is sintered into a sintered part <NUM>'). Here, <FIG> show a state where the stacked body of the three-dimensional shaped article is sintered.

In <FIG>, in the sintered part <NUM>', the metal particles are sintered, and in the support layer <NUM>' after heating, the binder and the like are thermally decomposed and then volatilized and removed, and therefore, due to the ceramic particles, the layer is turned into particles (a powder).

Here, as apparent from the comparison between <FIG>, and between <FIG>, when the constituent layer <NUM> is sintered, the volume decreases.

To describe the volume decrease (volume shrinkage), when the length in one direction after sintering is represented by L, the length in the one direction before sintering is represented by L<NUM>, the packing density of the particles before sintering is represented by A, and the sintering density is represented by B, the relationship of these factors is represented by the following formula <NUM>.

That is, the constituent layer <NUM> is shrunk such that the length L in one direction after sintering is represented as follows: (L<NUM><NUM> × (A/B))<NUM>/<NUM>.

In the following Table <NUM>, specific examples of the volume shrinkage ratio calculated from the packing density of the metal particles in the constituent material and the sintering density are shown.

In this manner, the stacked body of the three-dimensional shaped article is shrunk by sintering, and therefore, in the case where the volume shrinkage ratio of the support layer <NUM> in the space S is lower than the shrinkage ratio of the stacked body of the three-dimensional shaped article after sintering, the stacked body (constituent layer <NUM>) of the three-dimensional shaped article is distorted. Due to this, in this embodiment, the components of the support layer forming material and the formulation thereof are determined so that the volume shrinkage ratio of the support layer <NUM> in the space S is higher than the shrinkage ratio of the stacked body of the three-dimensional shaped article after sintering.

Next, one example of the three-dimensional shaped article production method to be performed using the above-mentioned forming apparatus <NUM> (an example corresponding to <FIG>) will be described with reference to a flowchart.

Here, <FIG> is a flowchart of the three-dimensional shaped article production method according to this embodiment.

As shown in <FIG>, in the three-dimensional shaped article production method according to this embodiment, first, in Step S110, the data of the three-dimensional shaped article is acquired. More specifically, the data representing the shape of the three-dimensional shaped article is acquired from, for example, an application program or the like executed by a personal computer.

Subsequently, in Step S120, data for each layer are created. More specifically, in the data representing the shape of the three-dimensional shaped article, the three-dimensional shaped article is sliced according to the shaping resolution in the Z direction, and bitmap data (cross-sectional data) are created for each cross section.

At this time, the bitmap data to be created are data discriminated between the three-dimensional shaped article formation region (constituent layer <NUM>) and the three-dimensional shaped article non-formation region (support layer <NUM>).

Subsequently, in Step S130, it is determined whether the data of the layer to be formed are the data for forming the three-dimensional shaped article non-formation region (support layer <NUM>) or the data for forming the three-dimensional shaped article formation region (constituent layer <NUM>). This determination is performed by the control section included in the control unit <NUM>.

In this step, in the case where the data is determined to be the data for forming the support layer <NUM>, the process proceeds to Step S140, and in the case where the data is determined to be the data for forming the constituent layer <NUM>, the process proceeds to Step S150.

In Step S140, by ejecting the support layer forming material from the support layer forming material ejection section <NUM> based on the data for forming the support layer <NUM>, the support layer forming material is supplied.

Then, when the support layer forming material is ejected in Step S140, an electromagnetic wave (ultraviolet ray) is irradiated (energy is applied) from the electromagnetic wave irradiation section <NUM> in Step S160, whereby the ejected liquid droplet (the support layer <NUM>) is solidified.

On the other hand, in Step S150, by ejecting the constituent material from the constituent material ejection section <NUM>, the constituent material is supplied.

Then, the process from Step S130 to Step S170 is repeated until it is determined in Step S170 that the formation of the stacked body of the three-dimensional shaped article based on the bitmap data corresponding to the respective layers created in Step S120 is completed.

Then, the stacked body of the three-dimensional shaped article formed in the above steps is heated in a high-temperature chamber (not shown) in Step S180. More specifically, the three-dimensional shaped article formation region (constituent layer <NUM>) is sintered, and the resin component and the like of the surrounding support layer <NUM> are decomposed and removed, whereby the support layer <NUM> is turned into particles with the ceramic particles. Here, the volume shrinkage ratio of the support layer <NUM>' after heating is higher than the volume shrinkage ratio of the constituent layer <NUM> (sintered part <NUM>') after heating (the volume of the support layer <NUM>' after heating corresponding to the space S is smaller than the volume of the sintered part <NUM>').

Then, accompanying the completion of Step S180, the three-dimensional shaped article production method of this embodiment is completed.

Specific examples of the shape of the three-dimensional shaped article configured as described above will be described.

<FIG> are schematic exploded side views showing the specific examples, and among these, <FIG> shows a shape in which two flat plates extending in the X direction are joined in one side, and therefore, slopes are formed. <FIG> shows a shape in which two bottomless cylinders are overlapped with each other. <FIG> shows a shape which is a bottomed cylindrical shape and has portions with different inner diameters. Further, <FIG> shows a shape in which a tunnel P corresponding to a pipe is formed in the shape of <FIG> shows a dome-like shape. The region outside and at the bottom of the cylinder in 9B, under the stepped portion, could also be considered to be a space. Also in the tunnel P, the support layer <NUM> is formed such that the volume shrinkage ratio of the support layer <NUM> in the space S in the tunnel P is higher than the shrinkage ratio of the stacked body of the three-dimensional shaped article.

As described above, the three-dimensional shaped article production method of this embodiment is a three-dimensional shaped article production method for producing a three-dimensional shaped article by stacking layers to form a stacked body.

Then, the method includes the constituent layer formation step (corresponding to Step S150) of forming the constituent layer <NUM> which corresponds to the constituent region of the three-dimensional shaped article, the support layer formation step (corresponding to Step S140) of forming the support layer <NUM> which is in contact with the constituent layer <NUM> and supports the constituent layer <NUM>, and the sintering step (corresponding to Step S180) of sintering the constituent layer <NUM>.

Here, the support layer <NUM> is configured such that as compared with the volume decrement accompanying the sintering step of a space S surrounded by the constituent layer from at least two directions, the volume decrement accompanying the sintering step of the support layer <NUM> which supports the constituent layer <NUM> in the space S is larger. That is, the volume decrement of the support layer <NUM> is larger than that of the space S.

That is, the support layer <NUM> is configured such that the shape of the support layer <NUM> changes in response to the volume change (shrinkage) accompanying the sintering of the constituent layer <NUM>, and therefore, the support layer <NUM> does not hinder the shrinkage accompanying the sintering of the constituent layer <NUM>. Due to this, the deformation of the sintered body (sintered part <NUM>') of the three-dimensional shaped article can be suppressed, and thus, the three-dimensional shaped article with high accuracy can be produced.

Incidentally, the "volume decrement accompanying the sintering step of a space S surrounded by the constituent layer <NUM>" refers to a volume decrement based on the constituent material of the constituent layer <NUM>, and refers to a volume decrement, after the sintering step, of the space S in the case where the support layer <NUM> is not present in the space S.

Further, the "space S surrounded by the constituent layer <NUM> from at least two directions" refers to, for example, an internal space whose volume decreases when the overall shape is isotropically shrunk such as an internal space (space S) having a bottomed or bottomless cylindrical shape (for example, corresponding to <FIG>) or an internal space having a cup-like shape (for example, corresponding to <FIG>) such that an opening portion is larger or smaller than a bottom portion.

In the embodiment of the three-dimensional shaped article production method shown in <FIG>, the support layer <NUM> is structurally changed (partially turned into the form of particles from a cured state by decomposing and removing a portion) accompanying the sintering step in the entire portion which supports the constituent layer <NUM> in the space S.

When the support layer <NUM> is configured such that at least a portion which supports the constituent layer <NUM> in the space S is structurally changed accompanying the sintering step, by the structural change, the shape of the support layer <NUM> changes in response to the volume change (shrinkage) accompanying the sintering of the constituent layer <NUM>, and therefore, the hindrance of the support layer <NUM> to shrinkage accompanying the sintering of the constituent layer <NUM> can be effectively suppressed.

Incidentally, the "structural change accompanying the sintering step" includes a configuration in which a portion of the support layer forming material is decomposed and removed and is turned into the form of particles as described above, and other than this, a configuration in which the structure of the support layer formed by, for example, a honeycomb structure, a truss structure, a lattice structure, or the like is collapsed accompanying the sintering step, the support layer forming material is melted and the shape of the support layer is changed before and after the melting, and the like.

Hereinafter, an embodiment of the three-dimensional shaped article production method in which a portion of the support layer <NUM> which supports the constituent layer <NUM> in the space S is structurally changed accompanying the sintering step will be described.

<FIG> are schematic views showing one example of the three-dimensional shaped article production process according to the invention. <FIG> show the three-dimensional shaped article production process in side view.

In this embodiment, as the support layer forming material, the following two materials: a first material 300a, which is composed of a resin component and the like, and in which all the components are decomposed and removed (volatilized) in the sintering step, and a second material 300b containing ceramic particles are used.

First, <FIG> shows a state where the support layer <NUM> in the layer <NUM> as the first layer is formed on the sample plate <NUM> using the support layer forming material ejection section <NUM>. In this embodiment, the first material 300a and the second material 300b are alternately disposed.

Here, <FIG> shows a state where the support layer forming materials (the first material 300a and the second material 300b) are ejected from the support layer forming material ejection section <NUM> and also a laser is irradiated onto the second material 300b from the laser irradiation section <NUM>, whereby the second material 300b is sintered.

Here, as shown in <FIG>, the stacked body of the three-dimensional shaped article of this embodiment has a cup-like shape (a state where a cup is inverted), and a portion surrounded by the constituent layer <NUM> forms a space S.

Then, finally, the stacked body of the three-dimensional shaped article formed as shown in <FIG> is heated in a high-temperature chamber (heating chamber) provided separately from the forming apparatus <NUM> according to this embodiment (the constituent layer <NUM> is sintered into a sintered part <NUM>'). Here, <FIG> shows a state where the stacked body of the three-dimensional shaped article is sintered.

In <FIG>, in the sintered part <NUM>', the metal particles are sintered, and in the support layer <NUM>' after heating, a portion 300a' corresponding to the first material 300a is decomposed and removed, and therefore disappears, and in a portion 300b' corresponding to the second material 300b, a sintered ceramic is left. That is, the first material 300a which is a portion of the support layer <NUM> is structurally changed, and the second material 300b which is a portion of the support layer <NUM> is not structurally changed.

Here, as apparent from the comparison of <FIG>, when the constituent layer <NUM> is sintered, the volume decreases. On the other hand, in a portion corresponding to the space S, a portion corresponding to the first material 300a is decomposed and removed, and therefore disappears, and therefore, the support layer <NUM> is configured such that the volume shrinkage ratio of the support layer <NUM> in the space S is higher than the shrinkage ratio of the stacked body of the three-dimensional shaped article.

In other words, in the three-dimensional shaped article production method, the support layer <NUM> is configured such that at least a portion which supports the constituent layer <NUM> in the space S includes a region (corresponding to the first material 300a) whose volume change accompanying the sintering step is relatively large and a region (corresponding to the second material 300b) whose volume change accompanying the sintering step is relatively small. Due to this, the shape of the support layer changes in response to the volume change (shrinkage) accompanying the sintering of the constituent layer effectively by the region whose volume change is relatively large, and the constituent layer during sintering can be supported efficiently by the region whose volume change is relatively small.

Incidentally, the "region whose volume change is relatively large and the region whose volume change is relatively small" are not particularly limited with respect to the difference thereof or the absolute amount thereof as long as the volume change ratio (shrinkage ratio) of the region whose volume change is large is larger than the volume change ratio (shrinkage ratio) of the region whose volume change is small, and also includes, for example, a case where there is substantially no volume change ratio (shrinkage ratio) in the region whose volume change is small as in the case of the portion 300b' corresponding to the second material 300b.

On the other hand, in the three-dimensional shaped article production method shown in <FIG>, at least a portion of the support layer <NUM> which supports the constituent layer <NUM> in the space S is powdered (turned into a powder or particles) accompanying the sintering step. Due to this, after the sintering step, the sintered body of the three-dimensional shaped article can be easily taken out from the support layer <NUM> (the support layer can be easily removed from the sintered body of the three-dimensional shaped article).

Further, in either of the three-dimensional shaped article production method shown in <FIG> and the three-dimensional shaped article production method shown in <FIG>, at least a portion of the support layer <NUM> which supports the constituent layer <NUM> in the space S is volatilized accompanying the sintering step. Due to this, by performing a step of removing a gas containing the volatilized component during the sintering step or after the sintering step, the support layer <NUM> can be easily removed from the sintered body of the three-dimensional shaped article. In the case where there is a space closed by the constituent layer <NUM>, the gas containing the volatilized component may be removed through the space among the particles in the process of sintering the particles contained in the constituent layer <NUM>. Further, in the case where a three-dimensional shaped article in which at least a portion is porous is shaped, the gas containing the volatilized component may be removed through the space among the sintered particles after the sintering step.

Claim 1:
A three-dimensional shaped article production method for producing a three-dimensional shaped article by stacking layers (<NUM>-50n) to form a stacked body (<NUM>), comprising:
a constituent layer formation step (S140) of forming a constituent layer (<NUM>) which corresponds to a constituent region of the three-dimensional shaped article by ejecting a constituent material;
a support layer formation step (S150) of forming a support layer (<NUM>) which is in contact with the constituent layer and supports the constituent layer, by ejecting a support layer forming material;
an energy applying step (S160) of applying energy to solidify the support layer (<NUM>);
repeating the constituent layer formation step, the support layer formation step and the energy applying step a plurality of times to form the stacked body; and
a sintering step (S180) of sintering the constituent layers in the stacked body, wherein
the support layer is configured such that as compared with the volume decrement during the sintering step of an internal space (S) in the constituent layer, the volume decrement during the sintering step of the support layer which supports the constituent layer in the space is larger,
characterised in that the support layer (<NUM>) is configured such that at least a portion which supports the constituent layer (<NUM>) in the space (S) includes:
a first support material (300a) whose volume change during the sintering step is relatively large compared to the volume change of a second support material during the sintering step, the second support material also being included in the portion which supports the constituent layer in the space, and
the second support material (300b) whose volume change during the sintering step is relatively small,
wherein the support layer (<NUM>) includes a region comprising the first support material (300a) and a region comprising the second support material (300b), the region comprising the second support material having a relatively small volume change during the sintering step compared to the volume change during the sintering step of the region comprising the first support material.