JPH07304104A - Method and apparatus for forming optically shaped product - Google Patents

Abstract

PURPOSE:To form a shaped product excellent in shape accuracy and quality. CONSTITUTION:The position of the surface 13 of a cured layer and the position of the liquid level 12 of a photosetting resin 2 are detected by a non-contact displacement sensor 16 and the liquid thickness of a layer cured next is detected. Laser power is automatically changed corresponding to a difference in liquid thickness to cure the photosetting resin 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a photofabricated product using a photocurable resin, and in particular, it is possible to obtain a highly accurate photofabricated product by controlling laser irradiation conditions by the liquid thickness. The present invention relates to a stereolithography method and a stereolithography apparatus capable of performing the stereolithography.

[0002]

2. Description of the Related Art FIG. 6 is a schematic block diagram showing a conventional stereolithography apparatus. In the figure, reference numeral 1 is a tank containing a photocurable resin 2, and a molding table 4 which is operated to be moved up and down by a drive device 3 is provided in the tank 1. Above the tank 1, there is provided a laser light scanning device 7 which scans the laser light 6 excited by the laser light excitation device 5 according to scanning data and guides the laser light 6 into the tank 1. Below the laser beam scanning device 7, the laser beam 8 guided into the tank 1 is exposed to the liquid surface 12 of the photocurable resin 2.
A condenser lens 9 for converging light is provided above. The driving device 3 and the laser light scanning device 7 include:
Create elevator drive data and scanning data based on the cross-sectional shape data of the product to be modeled C
The AD data processing device 10 is connected. When a product is produced by the above-mentioned optical modeling apparatus, the molding table 4 is positioned on the liquid surface 12 of the photocurable resin 2, and the scanning device 7 produced by the CAD data processing device 10 causes the laser light 6 from the laser light excitation device 5 to be emitted. Is scanned, and the scanned laser beam 8 is condensed on the liquid surface 12 by the condenser lens 9 to cure the photocurable resin 2 on the molding table 4 in accordance with the sectional shape of the product. After the curing of the resin for this cross-sectional shape is completed, the molding table 4 is slightly lowered by the driving device 3 according to the elevator driving data, a liquid thickness is provided on the hardening layer, and the laser thickness is set according to the scanning data according to the scanning data. The light 8 is scanned (irradiated), and a cured layer having a new sectional shape is continuously formed on the cured sectional shape. Then, the descending of the molding table 4 and the scanning of the laser beam 8 are repeatedly performed, and the stereolithography product 1 having a desired cross-sectional shape is obtained.
1 is produced.

In the fabrication of the above-mentioned stereolithography product 11, the shape accuracy of the stereolithography product 11 in the Z direction is determined by the amount of movement of the molding table 4, but the thickness of the photocurable layer depends on the fabrication shape, temperature, etc. Because it is greatly affected, variations occur, and stereolithography product 1
The quality of 1 becomes worse.

Therefore, in order to accurately control the thickness of the photo-cured layer to be formed, the photo-cured layer for detection is photo-cured simultaneously with the formation of the cured layer of the photo-molded article 11 on the upper surface of the molding table 4 beside the photo-molded article 11. By forming the layer 14, detecting the surface position of the photocurable layer 14 for detection by the position detection device 15, and performing the molding while supplying the photocurable resin 2, a molded article having excellent shape accuracy and quality can be obtained. A method for obtaining the same has been devised and disclosed in Japanese Patent Laid-Open No. 2-175134.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In Japanese Patent Publication No. 134, the surface position of the photocurable layer for detection 14 is detected, and the liquid thickness is controlled based on the detected value, that is, the amount of movement for lowering the molding table 4 is controlled. However, although the liquid thickness can be adjusted for modeling, the larger the number of photo-curing layers, the larger the cumulative error in the Z direction of the modeled product. Further, the position of the liquid surface 12 of the photocurable resin 2 varies depending on various conditions such as the volume and temperature of the shaped product, and it is difficult to maintain a constant value.

The present invention has been made in view of the above problems of the prior art. The surface positions of the photocurable layer and the photocurable resin liquid are accurately detected, and the laser irradiation condition is automatically determined by the value of the liquid thickness. It is an object of the present invention to provide a method and an apparatus for forming a stereolithography product, which can perform stable modeling by changing, and obtain a fabrication product with excellent shape accuracy and quality.

[0007]

In order to solve the above-mentioned problems, the method for forming a stereolithography product according to claim 1 of the present invention is based on data of all cross-sectional shapes of products designed by a computer-aided design system. According to the data of the one cross-section shape, the photocurable resin stored in the tank by scanning the laser light is cured to the one cross-section shape, and then the photocurability is obtained according to the data of the cross-section shape closest to the one cross-section shape. In the method for forming a stereolithography product of the above-mentioned product by successively forming a resin-cured cross-sectional shape on the resin cured to the above-mentioned one cross-sectional shape, the surface position of the cured layer and the photocurability The laser light irradiation condition of each layer is automatically controlled by detecting the liquid thickness from the surface position of the resin liquid.

According to a second aspect of the present invention, there is provided a molding apparatus for a stereolithography product, comprising: a tank containing a photocurable resin liquid; a molding table that can be raised and lowered in the tank; and a photocurable resin liquid from above the tank. In the apparatus for forming a stereolithography product having a light irradiation mechanism for irradiating a laser beam to the, a detection mechanism for detecting the surface position of the photocurable layer and the surface of the photocurable resin liquid is provided, and A control device for controlling the optimum irradiation condition of the laser light based on the detection signal is provided and configured.

[0009]

According to the structure of the above-mentioned claim 1, by detecting the surface position of the cured cured layer and the surface position of the photocurable resin liquid, the liquid thickness of the photocurable resin to be cured next is determined,
The laser irradiation conditions are automatically controlled based on the value of the liquid thickness, and the shape accuracy of the stereolithography product is improved.

According to the second aspect of the invention, the detection mechanism accurately detects the surface position of the photocurable layer and the liquid level of the photocurable resin, and then cures the liquid of the photocurable resin. Detect thickness. The control device automatically changes the laser light irradiation condition to the photocurable resin according to the detected value of the liquid thickness by the detection mechanism.

[0011]

[Embodiment 1] FIG. 1 is a schematic configuration diagram showing Embodiment 1 of an apparatus for forming a stereolithography product according to the present invention. The same components as those of the forming apparatus shown in FIG. 6 are designated by the same reference numerals and the description thereof will be omitted. In the figure, 16 is a non-contact displacement sensor for detecting the height of the position of the upper surface 13 of the stereolithography product 11 and the position of the liquid surface 12 of the photocurable resin 2. The non-contact displacement sensor 16 generates a high-frequency electric field to detect a change in capacitance according to the distance between the surface to be measured (the upper surface 13 and the liquid surface 12) and the non-contact displacement sensor 16, and detects this change. It is designed to measure displacement by replacing it with voltage change. 17 is
The non-contact displacement sensor 16 is a drive device that enables the non-contact displacement sensor 16 to move horizontally in order to detect the position height of the upper surface 13 of the stereolithography product 11 and the position of the liquid surface 12 of the photocurable resin 2. . The drive device 17 has a structure that can be moved so as to avoid it from above the tank 1.

Non-contact displacement sensor 16 and drive unit 17
Are controlled by the computer of the CAD data processing device 10. The computer of the CAD data processing device 10 incorporates a program for setting irradiation conditions of laser light based on a detection value detected by the non-contact displacement sensor 16. Further, the laser light scanning device 7 is provided with a mechanism for automatically changing the laser power according to a signal from the CAD data processing device 10.

Next, an embodiment of a method of forming a stereolithographic product using the forming apparatus having the above-mentioned structure will be described with reference to FIGS. 1 and 2. In the present embodiment, a sensor in which the reference distance between the non-contact displacement sensor 16 and the liquid surface 12 is 10 mm and the measurement range is 5 mm is used.

First, as a setup, the position of the liquid surface 12 of the photocurable resin 2 is detected by the non-contact displacement sensor 16, and then the molding table 4 is raised from the liquid surface 12 by about 2 to 3 mm.
The position of the upper surface 4a of the molding table 4 is detected. At this time, the molding table 4
Since the photocurable resin 2 is attached to the upper surface 4a of the above, it is wiped off well with a hand or the like. Then, the molding table 4 is lowered by the difference between the values detected on the liquid surface 12 and the upper surface 4a. As a result, the liquid surface 12 of the photocurable resin 2 and the upper surface 4a of the molding table 4 coincide with each other, and the preparation for molding is completed (see FIG. 2A).

Next, the molding table 4 is lowered by the driving device 3 by the pitch P of the hardened layer formed on the upper surface 4a of the molding table 4 (see FIG. 2B).

While scanning the laser light 6 excited by the laser light exciting device 5 in accordance with the scanning data, the laser light scanning device 7 irradiates the photocurable resin 2 on the molding table 4 with the laser light 8 to cause the molding table 4 to move. A hardened layer 11a for one layer is formed on the upper surface 4. In this embodiment, the pitch amount is P
= 0.1 mm, and the laser power is initially set to 10 mW. Then, the surface 13 of the hardened layer 11a is detected by the non-contact displacement sensor 16 (see FIG. 2C).

After the position of the surface 13 of the hardened layer 11a is detected, the molding table 4 is driven by the drive unit 3 for one pitch P (0.1 m).
m) After descending and waiting for the liquid surface 12 of the photocurable resin 2 to become smooth, the liquid surface 12 is detected (see FIG. 2D).

The detection signal is sent to the computer of the CAD data processor 10, and the liquid thickness H on the hardened layer 11 is detected from the values of the surface 13 and the liquid surface 12 of the hardened layer 11a (FIG. 2 (e)). )reference). Then, with this liquid thickness H, a laser power set value signal is instructed to the laser light scanning device 7, and the laser light 8 is irradiated based on this instruction.
At this time, the liquid thickness H and the laser power have the relationship shown in FIG. In this embodiment, the liquid thickness H is 0.15 mm. In this case, the laser power is automatically set to 12 to 13 mW as shown in FIG. Hereinafter, the same process operation is repeated, and the next cured layer is sequentially laminated on the pre-cured layer to finally form the desired stereolithographic article 11.

(Effect) According to this embodiment, in each cured layer,
Laser light irradiation can be controlled under optimum conditions according to the thickness of the liquid to be cured. As a result, the dimensional accuracy in the Z direction was 0.1 to 0.2 mm in the related art, but in the present embodiment, it is possible to form an optical modeling product with a high accuracy of 0.05 mm or less.

[0020]

[Second Embodiment] The molding apparatus of the present invention has the same basic structure as the molding apparatus of the first embodiment, so that the illustration is omitted and the following description will be made with reference to FIG. It ’s
The difference is that the laser beam scanning device 7 is provided with a mechanism capable of automatically changing the scanning speed of the laser beam in accordance with the signal from the CAD data processing device 10.

An embodiment of a method for forming a stereolithography product using the molding apparatus for a stereolithography product according to this embodiment will be described with reference to FIGS. 1 and 2. In this embodiment, the pitch amount is set to 0.1 mm and the laser scanning speed is initially set to 1300 mm / s. Similar to the first embodiment, the surface 13 of the hardened layer 11a and the liquid surface 12 of the photocurable resin 2 are detected. The detection signal is CAD
The data is sent to the computer of the data processing device 10, and the surface 13
Based on the value of the liquid surface 12 (liquid thickness H), a laser scanning speed set value signal is commanded to the laser light scanning device 7, and the laser light 8 is emitted. At this time, the liquid thickness H and the laser scanning speed have the relationship shown in FIG. In this embodiment, the liquid thickness H is 0.15 mm. In this case, the laser scan speed is set to 800 mm / s to 1200 mm / s. Hereinafter, the same process operation is repeated, and the next cured layer is sequentially laminated on the pre-cured layer to finally form the desired stereolithographic article 11.

(Effect) According to this embodiment, in each cured layer,
The scanning speed of the laser beam can be controlled to the optimum condition according to the thickness of the liquid to be cured. As a result, conventionally, Z
Although the dimensional accuracy in the direction was 0.1 to 0.2 mm, this embodiment can provide an inexpensive stereolithography product with a high accuracy of 0.05 mm or less.

[0023]

[Embodiment 3] The molding apparatus of the present invention has the same basic structure as that of the molding apparatus of Embodiment 1. Therefore, the illustration is omitted and the following description will be made with reference to FIG. It ’s
The difference is that the laser beam scanning device 7 is provided with a mechanism capable of automatically varying the power of the laser beam and the scan speed in parallel according to the signal from the CAD data processing device 10.

An embodiment of a method for forming a stereolithography product using the molding apparatus for a stereolithography product according to this embodiment will be described with reference to FIGS. 1 and 2. In this embodiment, the pitch amount is 0.1 mm, the laser power is 10 mW, and the laser scanning speed is 1300.
The initial setting is mm / s. Similar to the first embodiment, the surface 13 of the hardened layer 11a and the liquid surface 12 of the photocurable resin 2 are detected. The detection signal is sent to the computer of the CAD data processing device 10, and based on the values (liquid thickness H) of the surface 13 and the liquid surface 12, the laser light and the laser scanning speed set value signals are instructed to the laser light scanning device 7. The laser light 8 is emitted. At this time, the liquid thickness H and the laser power / laser scan speed have the relationship shown in FIG. In this embodiment, the liquid thickness H is 0.15 mm. In this case, the laser power is 11 to 12 mW and the laser scan speed is 900.
It is set to mm / s to 1200 mm / s. Hereinafter, the same process operation is repeated, and the next cured layer is sequentially laminated on the pre-cured layer to finally form the desired stereolithographic article 11.

(Effect) According to the present embodiment, in each cured layer,
The power of the laser beam and the scanning speed can be controlled under optimum conditions according to the thickness of the liquid to be cured. As a result, the modeling speed is further increased as compared with the second embodiment, and it is possible to provide a highly accurate and inexpensive optical modeling product.

The present invention can be configured as follows for the purpose of providing a method and an apparatus for forming a stereolithography product capable of obtaining a fabrication product excellent in shape accuracy and quality. After the data of the entire cross-sectional shape of the product designed by the computer-aided design system, the laser light is scanned according to the data of the one-sectional shape, and the photocurable resin housed in the tank is cured to the above-mentioned one-sectional shape. , By sequentially forming a cross-sectional shape obtained by curing the photo-curable resin according to the data of the cross-sectional shape closest to the one cross-sectional shape on the resin cured to the one cross-sectional shape, thereby producing a stereolithography product of the product. In the method of forming, from the surface position of the cured cured layer and the liquid surface position of the photocurable resin, the irradiation conditions of the laser light of each layer by detecting the liquid thickness of the layer to be cured next, per unit area A method for forming a stereolithography product, which is characterized by automatically controlling the irradiation amount. The method for forming a stereolithography product, characterized in that any one of laser power, scan speed, or laser power / scan speed is controlled as the irradiation condition of the laser light.

According to each of the above-mentioned constitutions, by detecting the surface position of the cured cured layer and the surface position of the photocurable resin liquid, the liquid thickness of the photocurable resin to be cured next is obtained, and this liquid thickness is obtained. The laser irradiation conditions are automatically controlled based on the value of, and the shape accuracy of the stereolithography product is improved.

In an apparatus for forming an optical molding product, which is equipped with a tank containing a photo-curable resin liquid, a molding table which can be raised and lowered in the tank, and a light irradiation mechanism for irradiating the liquid surface with laser light from above the tank. , A non-contact displacement sensor as a detection mechanism for detecting the surface position of the photocurable layer and the liquid level of the photocurable resin,
An apparatus for forming a stereolithography product, comprising a control device for controlling an optimum irradiation condition of laser light based on a detection signal from the non-contact displacement sensor. The detection mechanism is
An apparatus for forming a stereolithographic product, characterized by using a non-contact displacement meter for detecting a change in electrostatic capacity, a laser-based detection sensor, or a level meter using a capillary tube.

According to each of the above structures, the detection mechanism accurately detects the surface position of the photocurable layer and the liquid level of the photocurable resin, and detects the liquid thickness of the photocurable resin to be cured next. . The control device automatically changes the laser light irradiation condition to the photocurable resin according to the detected value of the liquid thickness by the detection mechanism.

[0030]

As described above, according to the method for forming a stereolithography product of the first aspect of the present invention, the liquid thickness can be accurately known by detecting the surface position of the hardened layer and the liquid surface position. It is possible to control the laser light irradiation conditions based on the liquid thickness. Therefore, when a plurality of photo-cured layers are laminated to form a stereolithography product, the stereolithography product is modeled under appropriate laser light irradiation conditions, so that a high-precision stereolithography product with stable quality performance can be obtained. Further, according to the optical-molded article manufacturing apparatus of claim 2, the liquid thickness is detected by the detection mechanism, and the irradiation condition of the laser light is controlled based on the detection signal, so that the irradiation condition of the proper laser light is obtained. Since the molding is performed, it is possible to obtain a highly accurate optical modeling product with stable quality performance.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of an apparatus for forming a stereolithography product according to the present invention.

FIG. 2 is a schematic process drawing showing each embodiment of the method for molding a stereolithography product according to the present invention.

FIG. 3 is a diagram showing the relationship between liquid thickness and laser power.

FIG. 4 is a diagram showing a relationship between liquid thickness and laser scanning speed.

FIG. 5 is a diagram showing the relationship between liquid thickness and laser power / laser scan speed.

FIG. 6 is a schematic configuration diagram showing a conventional stereolithography apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tank 2 Photocurable resin 3 Driving device 4 Molding table 10 CAD data processing device 11 Optical modeling product 12 Liquid level 13 Surface 16 Non-contact displacement sensor 17 Driving device

Claims (2)

[Claims] 1. From the data of the entire cross-sectional shape of a product designed by a computer-aided design system, the laser light is scanned according to the data of the single cross-sectional shape, and the photo-curable resin contained in the tank is cut into the one cross-section. After being cured into a shape, the above-mentioned product is formed by successively forming the cross-sectional shape obtained by curing the photocurable resin according to the data of the cross-sectional shape closest to the one cross-sectional shape on the resin cured into the one cross-sectional shape. In the method for forming a stereolithography product, the irradiation conditions of the laser light of each layer are detected by detecting the liquid thickness of the layer to be cured next from the surface position of the cured layer and the liquid surface position of the photocurable resin. A method for forming a stereolithography product, which is characterized by automatic control. 2. Forming of a stereolithography product comprising a tank containing a photocurable resin liquid, a molding table movable up and down in the tank, and a light irradiation mechanism for irradiating the liquid surface with laser light from above the tank. The device is provided with a detection mechanism for detecting the surface position of the photocurable layer and the liquid surface of the photocurable resin, and a control device for controlling the optimum irradiation condition of the laser light based on the detection signal from the detection mechanism. An apparatus for forming a stereolithography product, which is characterized in that