JP4246220B2 - Stereolithography equipment - Google Patents

Description

  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, an uncured fluid material is contained in a container and exposed and cured on the liquid surface side. It is related with the apparatus made to make it.

  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, for example, there is an apparatus described in Patent Document 1 (Japanese Patent Publication No. 2-48422). 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 to a depth exceeding one layer together with the platform, 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 automobile exhaust manifold prototypes, and plastic molding 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 (Japanese Patent Publication No. 7-10666), a dip coating method in which an uncured photo-curable resin is forcibly supplied onto the lower cured layer is employed, and a high viscosity is obtained. Proposals have been made that can achieve high speed and high layer thickness while using a photo-curable resin material, and attract 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.
Japanese Examined Patent Publication No. 2-48422 Japanese Examined Patent Publication No. 7-10666

  However, even in such an optical modeling apparatus, when using a photo-curing fluid material having a higher viscosity, a non-shrinkable fine particle material or a whisker-like substance equivalent thereto 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 the 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, the present invention can maintain the uncured fluid material at a uniform and good viscosity by appropriately stirring the material when the uncured fluid material is left in the container for a long time. An object is to provide an optical modeling apparatus.

In order to achieve the above object, the invention according to claim 1 selects on the liquid surface side a flowable material containing a photocurable resin and a substance having a specific gravity greater than that of the photocurable resin, contained in a modeling container. Is a photolithographic apparatus for forming an object by sequentially exposing to form a hardened layer in a predetermined shape and laminating the hardened layers sequentially, and having a specific gravity higher than that of the photocurable resin in a non-uniform flowable material The flowable material in the modeling container is passed through a material circulation passage provided in the modeling container so as to be evenly dispersed from the bottom surface side of the modeling container to the liquid surface side. and circulation means for flowing circulated by pump, so that the flowable material to flow circulation when working to shape the object is stopped, characterized in that a control means for controlling operation of said circulation means Ru der things to

In addition, as described in claim 2, the material circulation passages may be further spaced apart in the horizontal direction.

Furthermore, as described in claim 3, a plurality of holes may be formed in the material circulation passage.

According to the first aspect of the present invention, since the uncured fluid material separated in the container is flowed and circulated through the upper and lower material circulation passages by the pump of the circulation means and stirred in a uniform mixed state. Even if the device is left in the container for a long period of time, the fluidity of the fluid material is partially impaired and an excessive lifting load is applied to the movable platform, or a substance that should be included in the fluid material It is possible to prevent the required cured layer properties from being obtained due to shortage. Furthermore, since the control means for controlling the operation of the circulation means is provided so that the flowable material flows and circulates when the work for modeling the object is stopped, the flowable material in the container is appropriately stirred by circulation. Can do.

According to invention of Claim 2, since a fluid material can be made to flow also in the direction which turns around a vertical axis, a uniform mixed state can be obtained.

According to the third aspect of the present invention, since the flowable material flows in and out of the plurality of holes formed in the material circulation passage, a more uniform mixed state can be obtained.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
[First Embodiment]
FIG. 1 shows an example of a preferred embodiment.

  A modeling container 52 having a predetermined capacity shown in this figure is detachably supported by an apparatus main body (support) (not shown) equipped with a control unit and the like which will be described later, and L is a predetermined light accommodated in the modeling container 52. It is a fluid material containing a curable resin (for example, a UV curable resin). A horizontal free liquid level L of the fluid material 10 is formed on the upper part of the modeling container 52. The uncured flowable material is, for example, a liquid photocurable resin (for example, a polymerizable vinyl compound or an epoxy compound) having an average particle diameter of 3 to 70 μm having substantial non-shrinkage within a predetermined temperature range, Preferably, it is a paste-like composition (for example, the viscosity is 5,000 cps to 100,000 cps) in which fine particles (for example, glass beads or resin beads) of 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 fluid material is a whisker 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, a liquid photocurable resin) 5 to 30% by volume of this whisker).

  Further, the modeling container 52 keeps the height of the free liquid level L of the uncured material 10 at a constant height from the bottom surface of the modeling container 52 by a known liquid level adjusting means (not shown). Is provided with a movable platform 53 having an upper surface portion substantially parallel to the free liquid level L.

  The platform 53 is guided and supported so as to be movable up and down by a known lifting mechanism (not shown guide support means) so as to move in a vertical direction substantially orthogonal to the free liquid level. This guide support mechanism is controlled by a control unit 80. As a result, the platform 53 descends step by step with a predetermined descending pitch amount (predetermined moving amount) corresponding to the thickness of the hardened layer described later, and ascends to the vicinity of the initial position upon completion of modeling. .

  Further, a laser beam scanning device 60 (exposure means) is provided above the platform 53. The scanning device 60, for example, condenses the laser light emitted from the laser light source on the surface portion of the uncured material layer on the platform 53 while deflecting the laser light via a reflection optical system (not shown), and the light is preliminarily determined on the platform 53. Scanning is performed in both the main and sub scanning directions (horizontal direction) within the region.

The drawing pattern by the light from the optical scanning device 60 corresponds to the shape of each layer when the three-dimensional object to be formed is a laminated body of the hardened layer 13, and the scanning is a control stored in the apparatus main body 1. Controlled by unit 80. When a part of the fluid material 10 is cured from the free liquid surface to a predetermined depth by being exposed to light (selective exposure) scanned by the optical scanning device 60, the part of the material is cured to have a predetermined layer thickness. At the same time the layer is formed, it is laminated on the underlying cured layer.

Control unit 80, for example, is connected to the three-dimensional CAD (computer aided design) system (not shown), based on the modeling data of the three-dimensional CAD system or al, Ya elevating mechanism for moving the movable platform 53 The molding control for controlling the operation of the laser beam scanning device 60 and the motor for moving the dipper and the scraper for material supply (not shown) can be executed.

  In addition, the control unit 80 performs agitation control for operating the elevating mechanism in a state where the operation of the optical scanning device 60 is stopped. During this agitation control, the control unit 80 is movable with a stroke sufficiently larger than the descending pitch. The platform 53 can be reciprocated under the free liquid level, and the uncured fluid material 10 in the modeling container 52 can be stirred by the movable platform 53. The speed of the movable platform 53 during the reciprocating movement should be sufficiently larger than that during modeling, but may be relatively low when a sufficient reciprocating stroke is set and a stirring member as shown in FIG. 2 is provided. .

  The raising / lowering driving means controlled by the control unit 80 constitutes a first platform moving means for moving the movable platform 53 in units of the descending pitch (predetermined movement amount corresponding to the thickness of the hardened layer) and is movable. The second platform moving means is configured to reciprocate the platform 53 with a stroke larger than the descending pitch below the free liquid level L while the operation of the optical scanning device 60 (exposure means) and material supply means such as a dipper (not shown) is stopped. is doing. Therefore, when the movable platform 53 reciprocates up and down by the lifting mechanism as the second platform moving means, the fluid material 10 in the modeling container 52 may be stirred by the movable platform 53 having a large area. it can. In this case, when the operation stop time of the material supply means and the optical scanning device 60 (the time in which the device is left in a state where the molding is not performed) exceeds a predetermined time, for example, 5 hours, the control unit 80 controls the lifting mechanism. Agitation control to be operated as the second platform moving means is started. The stirring control time can be appropriately set according to the characteristics of the fluid material 10, the required modeling accuracy, the modeling speed, and the like.

  Further, in the present embodiment, a plurality of modeling containers 52 are provided and exchangeable, and the modeling work is performed using the modeling container 52 attached to the apparatus main body 1, while the lifting mechanism in the modeling container 52 removed from the apparatus main body is provided. It may be operated as the second platform moving means so that the modeling work and the stirring work of the fluid material to be used next can be executed in parallel.

  That is, the modeling container 52 may be removed from the apparatus main body and stirred on a dedicated stirring station. In this case, the agitation station has a drive power source (not shown) that drives the lifting mechanism.

  In that case, the elevating mechanism housed in the modeling container 52 is a motor or the like on the apparatus body side (elevating drive source of the first platform moving means) and an elevating drive source (external elevating drive source) in the stirring station. It functions as a guide support mechanism that can be driven by either.

  In the apparatus configured as described above, the control unit 80 operates the drive of the lifting mechanism, the motor that moves the material supply means such as the dipper and the scraper, and the optical scanning device 60 based on the modeling data from the three-dimensional CAD system. First, the dipper, which has been submerged below the free liquid level L at a position away from the platform 53, rises to a predetermined height while moving in synchronization with the movement of the scraper in the horizontal direction. Next, both the dipper and the scraper move horizontally to form an uncured material layer having a predetermined layer thickness from the uncured material 10 supplied on the platform 53. Next, the light from the optical scanning device 60 is condensed on the surface portion of the uncured material layer and scanned in both the main and sub scanning directions within a predetermined area on the platform 53 to form one cured layer. At the same time, this is laminated on the lower layer.

  When such a modeling operation is completed and the modeling object is taken out, the optical modeling apparatus is stopped until the next operation starts. In the apparatus of the present embodiment, in this stopped state, the uncured fluid material 10 can be agitated using, for example, the movable platform 53, that is, the movable platform 53 having a large area in the modeling container 52 is free liquid. By moving under the surface L, a substance having a specific gravity larger than that of the photocurable resin such as non-shrinkable fine particle material or whisker is sufficiently evenly dispersed in the photocurable resin to obtain a desired mixed state. Although it is possible, the material circulation means as described below is constructed, and stirring is performed thereby.

In FIG. 1, 71 is a pump that circulates the fluid material 10 in the modeling container 52 in a predetermined direction, 72 and 73 are spaced apart in the vertical direction and penetrate the wall on the right side of the modeling container 52 in FIG. These are upper and lower pipes that form a material circulation passage.
These pumps 71 and pipes 72 and 73 constitute material circulating means for circulating the fluid material 10 in the container 52 in a predetermined direction as shown by arrows in FIG. Yes.
The operation of the elevating mechanism drive source, the optical scanning device 60, the pump 71 and the like is controlled by a control unit (control means) 80.

In the state where the modeling work is finished, the modeling object is taken out, and the optical modeling apparatus is stopped until the next work starts, the uncured fluid material 10 may be stirred using the movable platform 53 as described above. However, in this embodiment, the fluid material 10 separated in the vertical direction in the container 52 due to the difference in specific gravity is circulated in the predetermined direction by the material circulation means and stirred. That is, as shown by the curved and folded arrows in FIG. 1, the fluid material 10 is caused to flow in the left direction in FIG. By sucking the fluid material 10, the fluid material 10 is flowed to the upper side (liquid surface side) and the pipe 72 side to the right in FIG. Stirring is performed by flow circulation so as to disperse from the side to the upper side (liquid level side).
Therefore, in the modeling container 52, 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 evenly dispersed in the photocurable resin to obtain a desired mixed state. Even when the apparatus is left for a long time with the fluid material 10 in the container 52, the mixing state of the above-mentioned fine particle material and the like mixed with the fluid material 10 and the photo-curing resin is not uniform or both Can be avoided, the fluidity of the flowable material is partially impaired, an excessive lifting load is applied to the movable platform, and there is a shortage of particulate material that should be included in the flowable material. The cured layer properties of can not be obtained.

  As shown in the plan view of FIG. 2, the upper and lower pipes 72 and 73 may be arranged so as to be shifted in the horizontal direction, and the fluid material 10 in the container 52 is also caused to flow in the direction of turning around the vertical axis. be able to. Other than this, the pipe 72 or 73 extends in the horizontal direction in the container 52 to form a plurality of holes in one or both of them, or the member directs the flow to the inner wall (for example, the bottom wall) of the container 52 It is possible to obtain a uniform mixed state as appropriate.

It is the schematic block diagram which shows an example of preferable embodiment of the optical modeling apparatus which concerns on this invention. It is a plane sectional view of the device shown in FIG.

Explanation of symbols

10 Flowable material (uncured mixed material including photo-curing resin)
52 Molding container
53 Mobile platform
60 Optical scanning device (exposure means)
71 Pump (circulation means)
72, 73 pipe (circulation means, material circulation passage)
80 Control unit (control means, lift control means)
L Free liquid level (Free surface)

Claims (3)

A fluid material containing a photocurable resin and a substance having a specific gravity greater than that of the photocurable resin contained in a modeling container is selectively exposed on the liquid surface side to form a cured layer in a predetermined shape, An optical modeling apparatus that models an object by sequentially laminating the cured layers,
The molding container is provided spaced apart in the vertical direction so that a substance having a specific gravity greater than that of the photocurable resin in the non-uniform flowable material is evenly dispersed from the bottom surface side of the modeling container to the liquid surface side. Circulating means for circulating the fluid material in the modeling container by a pump through the material circulation passage ;
Control means for controlling the operation of the circulation means so as to flow and circulate the flowable material when the operation of modeling the object is stopped;
An optical modeling apparatus characterized by comprising: The stereolithography apparatus according to claim 1, wherein the material circulation passage is further provided to be separated in the horizontal direction . The stereolithography apparatus according to claim 1 , wherein a plurality of holes are formed in the material circulation passage .

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