JP2005074988A - Photo-fabrication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photo-fabrication device capable of smoothly shaping which can maintain an uncured fluid material in uniform and preferable viscosity by properly stirring in advance the uncured fluid material when the material is left standing in a container for a long period of time, and can remove foreign matter or the like liable to be an obstacle for the photo-fabrication. <P>SOLUTION: The device sucks the fluid material 1 using a cylindrical stirring device 10 from a storage container 20 housing the material 1, stirs it and discharges it. In this structure, the stirring means is the rotation of a screw, and the stirred fluid material 1 is discharged from a discharge port 5 to the vicinity of the surface level of the storage container 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

Detailed Description of the Invention

The present invention relates to an optical modeling apparatus for modeling a three-dimensional object (three-dimensional object) using a photocurable fluid material, and in particular, contains a fluid material mixed with different materials in a container and the liquid surface side thereof. It is related with the apparatus made to carry out exposure hardening by.

  Conventionally, an uncured photo-curing resin is selectively exposed to form a hardened layer of a predetermined shape, and the hardened layer is sequentially laminated to enable one-piece modeling of complicated objects and assemblies. An optical modeling apparatus is known, and in this optical modeling apparatus, it is required to form a cured layer of each layer to be laminated with high accuracy and speed.

  As this type of stereolithography apparatus, there is one described in Patent Document 1, for example. In this apparatus, an elevating platform is disposed in a container containing an uncured photocurable resin liquid, and the liquid surface of the photocurable resin is selectively exposed by laser scanning to perform the above-described liquid surface measurement. After the photo-curing resin in the vicinity is cured to a predetermined shape on the platform, the cured layer is submerged with the platform to a depth exceeding one layer, and an uncured photo-curing resin liquid is automatically laminated on the platform, Next, the next uncured material layer can be formed relatively quickly by raising the platform to a position separating the stacking pitch amount (layer thickness of the layer to be stacked) from the free liquid level.

  By the way, this kind of stereolithography device is suitable for prototyping complex parts with low cost and in a short time, so in recent years, in addition to speeding up modeling work and further improving modeling accuracy Therefore, it is required that the shaped solid can be used for a wider range of applications. Specifically, parts that are exposed to high temperatures, such as automotive exhaust manifold prototypes, and plastic molds that are exposed to high temperatures and pressures are now required. .

  However, the photo-curing fluid material that can meet such demands has a high viscosity. As described above, the platform is submerged in an uncured liquid, and an uncured resin layer is automatically formed thereon (on the lower cured layer). In this method, it is impossible to rapidly spread one layer of uncured fluid material having a high viscosity on the platform. From the viewpoint of ensuring safety, it is preferable that the photocurable resin has a low odor and low volatility, but the above-described method requires a photocurable resin having a sufficiently low viscosity. Become.

  Therefore, as described in Patent Document 2, a dip coating method in which an uncured photocurable resin is forcibly supplied onto the lower cured layer is employed, and a high-viscosity photocurable resin material is used. Proposals have been made that have made it possible to achieve higher speed and higher layer thickness, and are attracting attention. This device contains an uncured photo-curable resin that can be cured by predetermined light and forms a free liquid surface of the resin, and moves into the container so as to move in a direction substantially perpendicular to the free liquid surface. A movable platform that is substantially parallel to the free liquid surface provided, a dipper that pumps uncured photocurable resin from the container and supplies it to the movable platform, and a direction perpendicular to the moving direction of the movable platform. It is provided with a scraper (doctor knife) that is provided so as to be movable and flattens the surface portion of the photocurable resin on the movable platform. Then, with the platform placed at a position lower than the free liquid surface by the stacking pitch amount, uncured photocurable resin is pumped up by the dipper and supplied onto the movable platform, and the surface portion of this photocurable resin is placed on the free liquid. It is flattened by a scraper that moves along the surface to quickly and uniformly form an uncured photocurable resin layer with a predetermined layer thickness in the vicinity of the free liquid surface on the platform. By repeating the step of selectively exposing and laminating and curing the photocurable resin, a three-dimensional shape of a required shape is formed.

  Further, even in such an improved optical modeling apparatus, when using a photo-curing fluid material having a higher viscosity, a non-shrinkable fine particle material or an equivalent whisker-like substance is uncured. Due to the difference in specific gravity between the material to be mixed and the photo-curing resin, if the mixed fluid material is left for a long time, the mixed state of the mixed substance and the photo-curing resin is not good. The problem of becoming uniform or separating the two was inevitable.

  Therefore, for example, if the stereolithography apparatus is left for a long time while the fluid material is contained in a container, the fluidity of the fluid material is partially impaired, so that an excessive lifting load is applied to the movable platform or the fluid material is included in the fluid material. Due to the shortage of the non-shrinkable fine particle material or the like to be obtained, the problem that the required cured layer properties cannot be obtained easily occurs.

  Therefore, in Patent Document 3, when an uncured fluid material is left in the container for a long time, a movable platform having a large area is reciprocated below the free liquid surface of the fluid material in the container. It is proposed to stir the uncured fluid material.

  According to Patent Document 4, a drastic improvement is attempted so as to regenerate a semi-solid formed from a reinforcing agent and a fluid material. A laser beam based on a storage container 2 for storing the photocurable resin of the fluid material 1, a table that is partially immersed in the storage container 2 and capable of moving up and down in the depth direction, and cross-sectional data obtained by slicing a three-dimensional shape. And a means for forming a cured layer on the table by irradiating the surface portion of the photocurable resin of the flowable material 1 with a predetermined amount of descent of the table and a laser beam based on the corresponding cross-sectional data. In the optical modeling apparatus for forming a laminated cured layer on the table by sequentially repeating the irradiation, a suction port 4 is provided in at least a part of the photocurable resin of the fluid material 1, and the suction port 4 A circulation path is formed between the surface of the fluidic material 1 and a stirring means for forcibly stirring the photocurable resin of the fluidic material 1, and the photocurable resin of the fluidic material 1 Move Characterized in that a transfer discharging means to discharge into the surface portion is disposed in said circulation line.

  In this structure, the flowable material 1 is sucked into the stirring means from the suction port 4 of the storage container 20 by operating the transfer and discharge means of the photocurable resin of the flowable material 1. This agitating means agitates the photocurable resin of the fluid material 1 with a torque by forced agitation and redisperses it. The re-dispersed photocurable resin is discharged to the surface portion of the storage container 20 by the pressure of stirring by the transfer and discharge means.

  That is, in Patent Document 4, an opening is provided in a container of uncured fluid material, a circulation pipe is formed between the opening and the surface of the resin, and the photocurable resin is forcibly stirred. Propose to let you. In addition, when the semi-solid material composed of the reinforcing material and the photo-curing resin is aggregated at the bottom of the container, a specific transfer / discharge means is activated to collect and re-disperse from the opening of the resin tank to the stirring means. Proposing at the same time.

      Japanese Examined Patent Publication No. 2-48422       Japanese Examined Patent Publication No. 7-10666       Japanese Patent Laid-Open No. 9-201875       JP-A-9-323362

Problems to be solved by the invention

  However, the method of Patent Document 3 is effective only when the apparatus does not perform modeling work, and particularly when modeling a large model or the like, since it cannot be stirred for a long time, the uncured flow It was not possible to completely prevent re-aggregation of the functional material. In addition, when using a photo-curing fluid material with higher viscosity, it is necessary to mix a non-shrinkable fine particle material or an equivalent whisker-like substance with an uncured photo-curing resin. Due to the difference in specific gravity between the material to be cured and the photo-curing resin, there is also a problem that when the mixed fluid material is left for a long time, the mixed state of the mixed substance and the photo-curing resin becomes non-uniform or both are separated. It was.

  On the other hand, in the method proposed in Patent Document 4, the working part that provides the specific stirring means and the working part that provides the specific transfer and discharge means must be installed below the free liquid surface of the resin. In order to propagate the power from the power source, it is necessary to seal the resin so that the resin does not leak out of the container. There has been a problem that the above-described reinforcing agent enters the gap between the seals and the movable part cannot be operated, or that the action of the valve stops due to adhesion to a check valve or the like. In practice, it has been difficult to stably operate the drawings proposed for a long time.

  In addition, these modeling resins cause foreign matter such as modeling scraps to float when modeling operations are repeated, which hinders the next modeling operation and deteriorates the surface properties of the resulting modeled object. Sometimes it was interrupted.

  Therefore, in order to solve the above-described problem, the present invention provides an uncured fluid material that is appropriately agitated beforehand when the uncured fluid material is left in the container for a long time. It is an object of the present invention to provide an optical modeling apparatus capable of maintaining a uniform and good viscosity and capable of smooth modeling capable of removing foreign matters in a resin that may cause an optical modeling obstacle.

Means for solving the problem

  The present invention according to claim 1, which solves the above-mentioned problems, selectively exposes the fluid material 1 to form a cured layer of the fluid material 1, and sequentially laminates the cured layers to form a three-dimensional object. In the optical modeling method to model, this fluid material 1 is sucked in from the storage container 20 which accommodates this fluid material 1 using the cylindrical stirring apparatus 10, and is stirred and discharged. In this structure, the stirring means is rotation of a screw, and the stirred fluid material 1 is discharged from the discharge port 5 to the vicinity of the surface portion of the storage container 20.

  Invention of Claim 2 is invention of Claim 1, Comprising: It is comprised from the conveyance screw 3 and the cylindrical outer shell 7, This cylindrical outer shell 7 makes the outer shell of the conveyance screw 3 50% of the length of the shaft 6. The flowable material 1 can be circulated by covering the above. That is, in this structure, the above numerical limitation is appropriate in the comparison of the length of the cylindrical outer shell 7 and the shaft 6, thereby smoothing. The fluid material 1 can be circulated by suction and discharge.

  Invention of Claim 3 is invention of Claim 1, Comprising: It connects in the upper part of the shaft 6 with the motor 2 and the coupling 11, and by rotating the conveyance screw 3, this unhardened flow in the said container is carried out. When the material 1 is agitated, smooth torque transmission is possible.

  The invention of claim 4 is the invention according to claims 1 to 3, wherein the stirring device 10 is provided with a lattice-like frame and / or a net at the suction port 4 and / or the discharge port 5, When circulating the flowable material 1, the “foreign matter” floating on the flowable material 1 is filtered out by the lattice-like frame and / or the net, so that the “foreign matter” flows from the suction port 4. do not do.

  The invention of claim 5 is the invention of claims 1 to 4, characterized in that the opening of the suction port 4 is formed in a mortar shape at the bottom of the storage container 2. Thereby, the fluid material 1 is smoothly sucked into the suction port 4.

  Embodiments of an optical modeling apparatus according to the present invention will be described below with reference to the drawings. Note that, in each embodiment, the same parts are associated with the same reference numerals.

  (Embodiment 1) FIG. 1-a, FIG. 1-b, FIG. 1-c, and FIG. 2 show Embodiment 1 of the present invention. The uncured flowable material 1 has, for example, an average particle diameter 3 having substantial non-shrinkage within a predetermined temperature range as a reinforcing material for a liquid photo-curing resin (for example, a polymerizable vinyl compound or epoxy compound). It is a paste-like composition (for example, a viscosity of 5,000 to 100,000 cps) in which solid fine particles of about 70 μm, preferably about 10 to 60 μm are blended in an amount of 5 to 70% by volume, preferably 10 to 55% by volume, The fine particles are treated with a known silane coupling agent to increase the mechanical strength after curing. Alternatively, the uncured flowable material uses whiskers having a diameter of 0.3 to 1 μm and a length of 10 to 70 μm and an aspect ratio of 10 to 100 instead of the fine particles (in this case, liquid photocuring) The whisker may be blended in an amount of 5 to 30% by volume.

  Examples of the solid fine particles that can be preferably used include inorganic solid fine particles such as glass beads, talc fine particles, and silicon oxide fine particles; cross-linked polystyrene fine particles, cross-linked polymethacrylate fine particles, polyethylene fine particles, and polypropylene fine particles. These solid fine particles may be used alone, in combination of two or more, or in combination with whiskers.

  Examples of whiskers that can be preferably used include whiskers made of aluminum borate compounds, magnesium hydroxide sulfate compounds, aluminum oxides, titanium oxide compounds, silicon oxide compounds, and the like. It may be used, two or more kinds may be used in combination, or the above-described solid fine particles may be used in combination. The material of the reinforcing material is not particularly limited.

  1A, FIG. 1B, FIG. 1C, and FIG. 1D show the entire cylinder stirring apparatus 10. A blade is fixed to the shaft 6 in a spiral shape to form a conveying screw 3 (common name: lead screw blade). Although the preferred shape is depicted schematically in FIG. 4A, the illustration of the screw used in FIGS. 1 to 3 to be described later is more simplified (FIG. 4B) is synonymous with this. . A cylindrical outer shell 7 of a cylindrical stirring device covers 50% or more of the length of the shaft 6 and has a mechanism for rotating the conveying screw 3 by the power of the motor 2. A discharge port 5 is provided above the cylindrical stirring device 10, that is, above the cylindrical outer shell 7. On the other hand, a suction port 4 for the outer shell 1 is provided below the cylindrical stirring device 4. In this embodiment, the shape and movement state of the conveying screw 3 and the power for operating the conveying screw 3 are not limited.

  When the outer shell 1 of the cylindrical stirring device covers the conveying screw 3, the clearance between the blade of the conveying screw 3 and the outer shell 1 when viewed from a vertical section with respect to the shaft 6 is preferably 0.1 to 5 mm. . If it is 2 mm or more, the resin transfer efficiency is lowered, and if it is 0.1 mm or less, foreign matter and precipitates are easily clogged in the gap and the like, which adversely affects the rotation. There is also concern about heat generation due to friction. More preferably, 0.3 to 3 mm is preferable.

  The outer shell 1 of the cylindrical stirring device may substantially cover 100% or more of the length of the shaft 6, and when it exceeds 100%, it can be bent in any direction depending on the shape of the container provided ( FIG. 1-c).

  FIG. 1B shows a case where a coupling 11 is mounted between the motor 2 and the conveying screw 3, and maintenance is facilitated in the case of a component failure or the like.

  FIG. 1-d shows the upper part of the container required for actual work during installation and modeling work in the optical modeling machine by transmitting power between the motor 2 and the shaft 6 through a combination 8 of pulley and belt or gear. It was devised in consideration of not occupying the space.

  Further, the suction port 4 and the discharge port 5 can be provided with a foreign matter removing mechanism 9 that can filter solid foreign matter floating in the fluid material 1 from the outside. Specifically, it is a grid-like frame and / or net having many gaps and / or holes of 0.1 to 5 mm. If the diameter is smaller than 0.1 mm, the resin circulation is obstructed, and foreign matters larger than 5 mm enter between the conveying screw and the outer shell, thereby hindering activation. It is preferably 0.3 to 3 mm, and more preferably a lattice frame and / or net having a gap and / or hole of 0.5 to 3 mm.

  In FIG. 2, the resin container 20 in which the cylindrical stirring apparatus 10 is provided is shown. The arrow a indicates the direction in which the fluid material 1 circulates by starting the cylindrical stirring device 10.

  Next, the operation of this embodiment will be described. When the operation of the apparatus is started in the state of FIG. 2, in the cylindrical stirring apparatus 10, the conveying screw 3 is rotated by the power of the motor 2, and the photocurable resin advances in the direction of the arrow a, and flows by this strong rotational force. The material 1 is sucked up from the suction port 4 in the direction of arrow a, and this resin is stirred and discharged from the discharge port 5 in the direction of arrow a.

  Further, in order to obtain the suction force due to the rotation of the conveying screw 3, it is not necessary to cover the entire length of the shaft 6 with the cylindrical outer shell 1, but the pumping force by the suction force from the suction port 2 by covering at least 50% or more. Increases from the case where the cylinder 1 is 50% or less, so that the photocurable resin dispersed inside the cylindrical stirring device 10 is discharged near the liquid surface of the fluid material 1 so as to spring out from the discharge port 5. Is done.

  The discharged resin is preferably discharged below the free liquid level of the flowable material 1. By doing so, it is possible to suppress the disturbance and undulation of the liquid level, and it is possible to continue the agitation even during the optical modeling that requires a very stable liquid level.

  The cylindrical stirring apparatus 10 can be removed as necessary, and the mechanism can be used independently of the resin container of the optical modeling machine. For example, in a single stereolithography machine, when switching from a photocurable resin containing a reinforcing agent to a photocurable resin containing no reinforcing agent, the storage container containing the reinforcing agent removed and removed is used. It is possible to perform a treatment so that a uniform state can always be maintained even during a period of attachment and non-use.

(Embodiment 2) FIG. 3 shows Embodiment 2 of the present invention. In these drawings, an arrow “a” is a circulation path of the fluid material 1, and the cylindrical agitator 10 is connected to this path “a”.
In this embodiment, an opening 22 is formed at the bottom of the resin storage container 20, and the suction port 4 of the cylindrical stirring device 10 is connected to the bottom opening 22. The bottom opening 22 is wide on the upper side of the resin storage container 20, and has a mortar-shaped cross section that gradually becomes thinner toward the suction port 4. In this case, the bottom opening 22 may be a cone, a pyramid, a semi-ellipse, or the like as long as the top of the resin storage container 20 is wide and narrows toward the suction port 4.

  In such an embodiment, the fluid material 1 can be collected in a concentrated manner at the suction port 4 without stagnation.

  The configuration 23 is a control device for the motor 2 that circulates the flowable material 1 in the modeling container 1 in a predetermined direction, and the number of rotations of the motor can be arbitrarily controlled according to the characteristics (viscosity, etc.) of the resin. . Moreover, this control apparatus 23 is connected with the computer 21 of the optical modeling apparatus, and can also control a rotation speed according to the motion of the modeling apparatus. For example, a more uniform flow can be achieved by reducing the number of revolutions during laser irradiation in the exposure process in order to minimize the disturbance of the liquid level or by increasing the number of revolutions during the movement of the modeling plate 24. The state of the conductive material 1 can be maintained.

  Therefore, in the resin storage container 20, a substance having a specific gravity larger than that of the photocurable resin such as non-shrinkable fine particle material or whisker can be sufficiently uniformly dispersed in the photocurable resin to obtain a desired mixed state. Even when the apparatus is allowed to stand for a long time with the flowable material 1 containing the reinforcing agent in the resin storage container 20, the mixed state of the flowable material 1 can be obtained by operating only the cylindrical stirring device 10 independently. Can be avoided, and the flowability of the flowable material is partially impaired, so that an excessive lifting load is applied to the modeling plate 24 or is included in the flowable material 1. There is no shortage of fine particle material or the like, and the required cured layer properties cannot be obtained.

The invention's effect

The present invention can stir and circulate the resin even during stereolithography, which has been difficult in the past, particularly during the exposure process, and thereby sufficiently stir the uncured fluid material. As a result, even when the apparatus is left for a long time with the flowable material in the container, the flowability of the flowable material is partially impaired, and an excessive lifting load is applied to the movable platform. It is possible to prevent the required cured layer properties from being obtained due to a shortage of substances to be included.
In addition, “foreign substances” floating in the flowable resin during this circulation can be filtered out by the lattice frame and / or net, and the production of stereolithography products with excellent quality, especially surface properties, can be continued stably. I can do it.

It is sectional drawing of Embodiment 1 of this invention. It is sectional drawing of another example of Embodiment 1 of this invention. It is sectional drawing of another example of Embodiment 1 of this invention. It is sectional drawing of another example of Embodiment 1 of this invention. It is sectional drawing which shows the action | operation of Embodiment 1 of this invention. It is sectional drawing of Embodiment 2 of this invention. It is the definition about the screw used for the description regarding the conveyance screw 3 of this invention, and FIGS.

Explanation of symbols

1. Flowable material Motor 3. 3. Conveying screw Inlet 5 Discharge port 6. Shaft 7 Cylindrical shell 8. 8. Combination of pulley and belt or gear Foreign matter removal mechanism 10. Cylindrical agitator 11. Coupling 20. Resin storage container 21. Computer of stereolithography apparatus 22. Bottom opening 23. Control device for motor 2 24. Modeling plate

Claims (5)

In a stereolithography method for forming a three-dimensional object by sequentially exposing the fluid material 1 to form a cured layer of the fluid material 1 and sequentially stacking the cured layers, the fluid material 1 is accommodated. An optical modeling apparatus characterized by sucking the fluid material 1 from a storage container 20 using a cylindrical stirring device 10 and stirring and discharging the fluid material 1. The agitator 10 includes a conveying screw 3, a shaft 6, and a cylindrical outer shell 7. The cylindrical outer shell 7 is configured by covering the outer shell of the conveying screw 3 with 50% or more of the length of the shaft 6. The optical modeling apparatus according to claim 1, wherein the fluid material 1 can be circulated. The stirring device 10 is connected to the upper portion of the shaft 6 by a motor 2 and a coupling 11 and rotates the transport screw 3 to stir the uncured fluid material 1 in the storage container 20. The optical modeling apparatus according to claim 1 and 2. The stirring device 10 is provided with a lattice-like frame and / or net at the inlet of the suction port 4 and / or the discharge port 5, and floats on the fluid material 1 when circulating the fluid material 1. The stereolithography apparatus according to claim 1, wherein the “foreign matter” is filtered out by the grid-like frame and / or the net. The stereolithography apparatus according to claim 1, wherein an opening of the suction port 4 has a mortar shape at the bottom of the storage container 20.

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