JP3207484B2 - Stereolithography apparatus and stereolithography method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical shaping apparatus and an optical shaping method, and more particularly to an optical shaping apparatus in which an optical scanning area is enlarged by devising a reflection optical system and an optical shaping method using the same. .

[0002]

2. Description of the Related Art In recent years, an optical shaping apparatus for shaping a three-dimensional object (three-dimensional object) by applying a plate making technique has been developed. This apparatus exposes an uncured photocurable resin (hereinafter, also referred to as an uncured resin liquid) to form a cured layer, and sequentially laminates the cured layers into a three-dimensional object.
By creating data of the cross-sectional shape of each layer using an electronic computer, etc., and selectively exposing the uncured resin liquid based on the data, complicated three-dimensional shapes such as templates and models at the time of product development Objects can be shaped.

An example of this type of stereolithography apparatus is disclosed in Japanese Patent Application Laid-Open No. 3-227222. In this apparatus, a laser beam was scanned on the liquid surface of the molding tank containing the uncured resin liquid to cure the uncured resin liquid near the liquid surface into a predetermined shape, and the cured layer was submerged in the molding tank. rear,
The next cross-sectional layer is laminated and adhered thereon. The laser beam scanning device (scanning device)
Is, for example, a first reflecting mirror that rotates while reflecting laser light from a laser light source and scans the laser light in a first scanning direction, and rotates while reflecting light from the first reflecting mirror. And a second reflecting mirror that scans the laser beam in a second scanning direction orthogonal to the first scanning direction. Each of the reflecting mirrors corresponds to a shaping pattern of each hardened layer by a scanning motor. The drive is controlled.

[0004]

However, in such a conventional stereolithography apparatus and stereolithography method, the light from the light source is reflected by the first and second reflecting mirrors and the second reflecting mirror is formed. From the second reflecting mirror to the surface of the photo-curing resin when the user wants to enlarge the size of the three-dimensional object that can be formed by enlarging the light scanning area. There has been no other choice but to increase the distance or increase the scanning rotation angle of the second reflecting mirror. For this reason, there has been a problem in that the resolution is reduced due to an increase in the size of the apparatus or the light quantity is insufficient, or there is a problem that the focusing is not performed near the maximum deflection angle of the second reflecting mirror and the modeling accuracy is reduced.

Accordingly, the present invention is to increase the distance from the second reflecting mirror to the photocurable resin liquid surface by making the light projecting paths from the second reflecting mirror to the photocurable resin liquid surface parallel. The scanning area is expanded without any
It is an object of the present invention to provide a high-precision optical shaping apparatus, and further to ensure the strength of the formed object.

[0006]

In order to achieve the above-mentioned object, the invention according to the first aspect of the present invention provides a photo-curing device that scans light from a light source with a reflecting optical system having a first reflecting mirror and a second reflecting mirror. In an optical shaping apparatus for forming a three-dimensional object by forming a cured layer of a resin and sequentially laminating and integrating the cured layers, in a stereolithography apparatus, a predetermined distance is symmetrical with respect to a rotation center axis of a second reflecting mirror. The third reflecting mirror and the fourth reflecting mirror are provided as fixed reflecting mirrors, and the light reflected by the second reflecting mirror is reflected by any of the third reflecting mirror and the fourth reflecting mirror. The scanning in the second scanning direction is performed, and a plurality of sets of third and fourth reflecting mirrors are juxtaposed in the second scanning direction. At the same time, the light projecting path from the light source to the third and fourth reflecting mirrors of each set is switched. It is characterized in the provision of the switch means.

Further, according to a third aspect of the present invention, there is provided a stereolithography method wherein when a next cured layer is laminated on an already formed lower cured layer, the second reflecting mirror for scanning light is used. The moving range is changed to a range different from that when the lower hardened layer is formed, and the optical scanning area using the third reflecting mirror and the optical scanning area using the fourth reflecting mirror form the lower hardened layer. The position is shifted in the second scanning direction from the position at the time of the movement.

[0008]

According to the first aspect of the present invention, the third reflecting mirror and the fourth reflecting mirror provided as fixed reflecting mirrors are symmetrical to each other with respect to the rotation center axis of the second reflecting mirror and are separated from each other by a predetermined distance. The light reflected by the second reflecting mirror is provided at an interval, and is reflected by an arbitrary fixed reflecting mirror among the third reflecting mirror and the fourth reflecting mirror. Accordingly, a path for projecting light from the second reflecting mirror to the liquid surface of the photocurable resin via the third reflecting mirror, and a light beam from the second reflecting mirror to the surface of the photocurable resin via the fourth reflecting mirror. The path is parallel to the path, and the scanning area is enlarged without increasing the distance from the second reflecting mirror to the surface of the photocurable resin.

According to the second aspect of the present invention, the light projecting path from the light source to each set of the third and fourth reflecting mirrors arranged in parallel in the second scanning direction is switched by the switching means.
Therefore, a very long three-dimensional object can be formed with a simple configuration. According to the third aspect of the present invention, when forming the upper and lower cured layers to be laminated, the rotation ranges of the second reflecting mirror are changed so as to be different from each other, and the light scanning area using the third reflecting mirror and the fourth reflecting mirror are changed. The optical scanning region using the mirror is shifted in the second scanning direction from the position where the lower cured layer was formed. Therefore, the strength of the molded object is ensured by shifting the position of the joint between the cured layer on the third reflecting mirror side and the cured layer on the fourth reflecting mirror side between the upper and lower cured layers.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 to FIG. 3 are views showing an embodiment of the optical shaping apparatus according to the present invention. First, the configuration will be described. In FIGS. 1 and 2, reference numeral 11 denotes a shaping tank, in which an uncured resin liquid 13 of a predetermined photocurable resin is stored. This photocurable resin has a property of being cured by, for example, light in an infrared region (may be light in an ultraviolet region or visible light). Reference numeral 12 denotes a plate-shaped molding shelf arranged in the molding tank 11, and the molding shelf is
Numeral 12 is supported by elevating drive means 14 so as to be able to move up and down. The elevation drive means 14 has, for example, a servo motor and a ball screw mechanism (not shown), and positions the modeling shelf 12 below the liquid level of the uncured resin liquid 13 and, if necessary, a predetermined amount (for a cured layer q to be described later). (An amount corresponding to the thickness).

A laser beam scanning device 15 is provided above the modeling tank 11. The laser beam scanning device 15 includes an optical system 17 for shaping a laser beam 100 emitted from a laser light source 16 and a reflection optical system 20 described later. And deflects the laser beam 100 (modeling tank 1
The light 100 is condensed on the liquid surface of the uncured resin liquid 13 while being projected toward the first scanning direction (X direction in FIG. 2).
And a second scanning direction orthogonal thereto (Y direction in FIG. 2)
Is to be scanned. The laser light 100 emitted from the laser light source 16 is light suitable for the properties of the photo-curable resin 13, for example, light in an infrared region (light in an ultraviolet region or visible light or the like). Further, the drawing pattern by the optical scanning of the laser light scanning device 15 is such that the modeled object is formed by a plurality of cured layers q.
When a three-dimensional object that is a laminate of (each layer pattern shape may be the same or different) corresponds to each shape of the cured layer q, the uncured resin liquid in the modeling tank 11
The uncured resin liquid 13 between the liquid surface 13 and the modeling shelf 12 is selectively exposed and cured in accordance with the drawing pattern, thereby forming a cured layer q having a required shape. And the hardened layer q is
When the lowermost layer is formed, it is adhered to the image shelf 12, and the hardened layer q above it is sequentially laminated on the lower hardened layer q by the lowering of the modeling shelf 12 and the above-described exposure operation.

Reference numeral 18 denotes a lifting drive means 14, a laser beam scanning device
15 and a laser light source 16. The control device 18 includes a known three-dimensional CAD (computer aided desig).
n) System 19 is connected. This control device 18
Based on the cross-sectional shape data transmitted from the dimensional CAD system 19, data for drawing (exposure) by the laser light scanning device 15 and the laser light source 16 or data for driving the modeling shelf 12 up and down is created, and the up and down driving is performed. The means 14, the laser light scanning device 15, and the laser light source 16 are controlled. More specifically, the three-dimensional CAD system 19 can create data of a plurality of cross-sectional shapes at minute intervals with respect to the designed three-dimensional object. The pattern data is transmitted to the controller 18 as the thickness data of the hardened layer q. Further, the control device 18 generates a scanning drive signal for driving the laser beam scanning device 15 in both the X and Y scanning directions and a drive signal for the laser light source 16 from the transmitted drawing pattern data, and corresponds to the layer thickness data. Driving signals for the elevation driving means 14 are generated, and these driving signals are outputted to the elevation driving means 14, the laser beam scanning device 15 and the laser light source 16 at a predetermined timing.

FIG. 2 is a diagram showing a specific configuration of the laser beam scanning device 15. As shown in FIGS.
The reflecting optical system 20 of the laser beam scanning device 15 is a first reflecting mirror.
21 and a second reflecting mirror 22. First reflector 21
Is only rotated a predetermined angle range in the reflected while around the rotation center axis C ₁ of the laser beam 100 that is shaped by the emitted optical system 17 from the laser light source 16, the laser beam is scanned 100 in the X direction of the figure Things. The second reflecting mirror 22 is a first reflecting mirror.
Only rotated a predetermined angle range with a laser beam 100 (reflected beam) further reflected while around the rotational axis C ₂ of the 21, a reflecting mirror for scanning in a direction perpendicular to the laser beam 100 with the X direction. The first reflecting mirror 21 and the second reflecting mirror 22 are connected to motors 23 and 24 such as servo motors so that the rotation center axes C ₁ and C ₂ are orthogonal to each other.

On the other hand, in the vicinity of the second reflecting mirror 22, the third reflecting mirror 25 and the fourth reflecting mirror 25 are arranged symmetrically with respect to the rotation center axis C2 of the _second reflecting mirror 22 and at a predetermined distance. Reflector
26 is fixedly provided. The third reflecting mirror 25 and the fourth reflecting mirror 26 are fixed reflecting mirrors whose reflecting surfaces are located on the second reflecting mirror 22 side, and the liquid of the uncured resin liquid 13 is separated so that the lower ends thereof are separated from each other. The laser beam 100 is inclined with respect to the surface, and reflects the laser beam 100 from the second reflecting mirror 22 toward the modeling tank 11. Further, the motor 24 for driving the second reflecting mirror 22 receives the driving signal from the control device 18 and rotates the second reflecting mirror 22 in an angle range corresponding to the scanning of the laser light 100 in the Y direction. When the drive signal is received from the control device 18, the second reflecting mirror 22 is rotated by 90 degrees in the direction of the arrow as shown in FIG. The optical path is switched from either the third reflecting mirror 25 side or the fourth reflecting mirror 26 side to the other side (see FIG. 2). That is, in this embodiment, the laser light 100 reflected by the second reflecting mirror 22 is reflected by any of the third reflecting mirror 25 and the fourth reflecting mirror 26, and the uncured resin The scanning area 30A on one side in the Y direction or the scanning area 30B on the other side on the liquid surface of the liquid 13 is reached, and the scanning of the double width in the Y direction is continuously performed by the scanning rotation of the second reflecting mirror 22. To be able to do it.

Next, the operation will be described. First, three-dimensional CA
When a three-dimensional object is designed by the D system 19,
The dimensional CAD system 19 creates a plurality of cross-sectional shape data and the like of the object at minute intervals, and transmits the data to the control device 18 as drawing pattern and layer thickness data of the plurality of hardened layers q during modeling. You. Next, the control device 18 generates a scanning drive signal in both the X and Y scanning directions of the laser beam scanning device 15 and a driving signal of the laser light source 16 from the transmitted drawing pattern data, and corresponds to the layer thickness data. Driving signals for the elevation driving means 14 are generated, and these driving signals are generated at predetermined timing by the elevation driving means 14, the laser light scanning device 15, and the laser light source 16.
Is output to

In this state, the laser light 100 emitted continuously or intermittently in response to the drive signal from the laser light source 16 is deflected by the laser light scanning device 15 and projected onto the modeling tank 11. The light is focused on the liquid surface of the uncured resin liquid 13 and further scanned in the X and Y directions. Therefore, the uncured resin liquid is scanned by the optical scanning of the laser beam scanning device 15.
Selective exposure of a predetermined drawing pattern is performed on the liquid surface of 13,
The uncured resin liquid 13 between the liquid level of the uncured resin liquid 13 in the modeling tank 11 and the modeling shelf 12 cures to a cured layer q having a required shape. When the hardened layer q is the lowermost layer, the hardened layer q is adhered to the image shelf 12 simultaneously with hardening.

When the drawing pattern straddles the scanning area 30A on one side in the Y direction and the scanning area 30B on the other side, first, the exposure operation is performed for all or a part of the drawing pattern in the area 30A or 30B on one side. Is performed, and then all or part of the drawing pattern is exposed in the other region 30B or 30A. Note that this area switching is performed once or more times for each cured layer q.

Specifically, after the exposure operation in one area 30A or 30B is performed, the second reflecting mirror 22 is driven by the motor 24, and the uncured resin liquid 13 in the modeling tank 11 is removed. On the liquid surface, a scanning area 30A on one side in the Y direction using the third reflecting mirror 25 and a scanning area 30B on the other side in the Y direction using the fourth reflecting mirror 26 are switched. Both regions 30A at the time of switching, since the scanning point in 30B are located symmetrically with respect to the center line C _3, a scan rotation angle of the second reflecting mirror 22 at the time of scanning by appropriately setting the center line C _3, two scanning regions 30A and 30B extending from the vicinity to one side and the other side in the Y direction can be continuously formed, and the reflection and reflection after the second reflection mirror 22 can be formed.
The scanning area can be enlarged with a simple configuration in which the light projecting paths are arranged in parallel on one side and the other side in the Y direction.

When the exposure operation is completed and a hardened layer q having a predetermined shape is formed on the modeling shelf 12, the elevation driving means 14
, The modeling shelf 12 is lowered by the thickness of the hardened layer q,
The operation for forming the next cured layer q is started in the same manner as described above. Then, the same operation is repeated until the uppermost hardened layer q, and the upper hardened layer q is sequentially laminated on the lower hardened layer q, whereby a three-dimensional object including a plurality of hardened layers q is formed. You.

As described above, in the present embodiment, the second reflecting mirror 22
From the second reflecting mirror 22 through the fourth reflecting mirror 26 to the light projecting path for irradiating the liquid surface (scanning surface) of the uncured resin liquid 13 with the laser light 100 through the third reflecting mirror 25 Laser light 10 on scanning surface
A light projecting path for irradiating 0 is provided in parallel. Therefore, even if the distance from the second reflecting mirror 22 to the scanning surface is not increased, the scanning area is doubled in the Y direction, the size that can be formed is large, and the compact and high-precision optical shaping apparatus is provided. can do.

By the way, when modeling with the optical shaping apparatus of the present embodiment, it is necessary to process well the joints between the cured layers on the exposure regions 30A and 30B (portion A in FIG. 1). FIG.
FIG. 2 is a view for explaining an embodiment of the stereolithography method of the present invention which can meet the problem. In the figure, the exposure regions 30A, hardened layer formed on the 30B qa, seam 33 of qb each other, the two curing layers vertically adjacent to each have different position in the Y direction, from above the center line C ₃ There are a plurality of hardened layers q having seams 33 at the off positions.

[0022] Referring to molding method seam portion in this example, for example, already formed the lower layer over the following hardened layer q ₁ (the upper layer) when stacking the cured layer q _2, to scan the laser beam 100 the range of rotation (scan rotation) of the second reflecting mirror 22 is changed to a different range than when forming the hardened layer q ₁ of the lower layer for a light scanning region 30A using the third reflection mirror 25 The light scanning area 30B using the fourth reflecting mirror 26 and the lower cured layer q
Position when forming a ₁ (symmetrical positions with respect to the center line C ₃₎
To the right in the figure. Specifically, for example, the scanning rotation range of the second reflecting mirror 22 can be changed between the upper and lower layers based on the pulse output of the encoder 24a attached to the motor 24. Therefore, the position of the joint 33 of the left and right cured layers qa and qb is shifted between the vertically adjacent cured layers q ₁ and q ₂ .

It is desirable to take in a very small amount of uncured resin liquid while leaving a slight gap between the cured layers qa and qb of each layer. Then, further when stacking the cured layer q ₃ of the upper layer, changed to a different range than when the scanning rotation range of the second reflecting mirror 22 to form a lower layer of the hardened layer q _2, the third reflecting mirror 25 from the position at which the optical scanning area 30B using the light scanning region 30A and the fourth reflecting mirror 26 to form a cured layer q ₁ of the lower layer to shift to the left in the drawing using. Thereafter, the position of the seam 33 between the hardened layers qa and qb of each layer is alternately shifted left and right by the same adjustment of the scanning area, so that the seam 33 is discontinuous in the three-dimensional object.

As described above, in the present embodiment, when forming the cured layer q, the rotation range of the second reflecting mirror 22 is appropriately changed, and the light scanning area 30A using the third reflecting mirror 25 and the fourth reflecting mirror 25 are used. Mirror 26
Is shifted in the second scanning direction from the position where the lower hardened layer q is formed, so that the hardened layer qa on the third reflecting mirror 25 side and the light scanning area on the fourth reflecting mirror 26 side Hardened layer q
The seams 33 with “b” are alternately shifted. Therefore, the strength of the formed three-dimensional object despite having the seam is sufficiently ensured.

FIG. 4 is a view showing another embodiment of the optical shaping apparatus according to the present invention. In the present embodiment, the same reference numerals are given to the same or equivalent components as those in the above-described example, and the duplicate description will be omitted. As shown in FIG. 4, in the present embodiment, a plurality of sets of the third reflecting mirror 25 and the fourth reflecting mirror 26 (hereinafter, also referred to as fixed reflecting mirrors 25 and 26) are provided in the second scanning direction. In this example, two sets of reflective optical systems 40 are arranged side by side. The reflection optical system 40 can be realized by juxtaposing the reflection optical systems 20 of the laser beam scanning device 15 in the second scanning direction as they are, but there is room for simplifying the configuration of the device. Therefore, in this embodiment, a third light source (not shown) is used.
The light projecting path to each pair of the fourth reflecting mirrors 25 and 26 is switched to an arbitrary path by an appropriate switching means.

The switching means is means for making the light source or / and the first reflecting mirror 21 movable in the Y direction so as to share a light-projecting path on the light source side with respect to a plurality of sets of fixed reflecting mirrors 25 and 26; Alternatively, an appropriate reflecting mirror is arranged on the light projecting path from the light source, and the reflecting mirror is rotated or moved in the Y direction to thereby fix the reflecting mirror.
This is a means for switching the light projection path to each set of 25 and 26. In the case of a movable type, at least one of the members from the light source to the second reflecting mirror 22 can be moved. In the case where the light projecting path is switched using a reflecting mirror, it is conceivable to arrange a light source at a position distant from each set of the fixed reflecting mirrors 25 and 26. The seam portion A ₁ of the cured layer
1 to ₃ are processed in the same manner as in the part A of FIG.

With this arrangement, it is possible to easily form a very long three-dimensional object in the Y direction by using a laser beam scanning device having a simple structure, and in particular, switching means for moving or rotating the reflecting mirror. Is provided, a laser beam scanning device having a simpler configuration can be realized.

[0028]

According to the first aspect of the present invention, the light reflected by the second reflecting mirror is reflected by any one of the third reflecting mirror and the fourth reflecting mirror to form the second reflecting mirror. The light projecting paths from the first to the light curing resin liquid surface are arranged in parallel, so that the distance from the second reflecting mirror to the light curing resin liquid surface and the scanning rotation angle of the second reflecting mirror are increased. Without doing
The scanning area can be doubled in the second scanning direction. As a result, it is possible to provide an optical shaping apparatus having a large size that can be formed, a small size, and high modeling accuracy.

According to the second aspect of the present invention, the third and the fourth are provided.
Since the light projecting path from the light source to each set of the reflecting mirrors is switched by the switching means, an extremely long three-dimensional object can be formed with a simple configuration. According to the invention described in claim 3, the joint between the cured layer on the third reflecting mirror side and the cured layer on the fourth reflecting mirror side is the second between the upper and lower cured layers.
, The intensity of the three-dimensional object to be formed can be sufficiently secured.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of an optical shaping apparatus according to the present invention.

FIGS. 2A and 2B are configuration diagrams of a reflection optical system according to an embodiment. FIG. 2A is a front view of the reflection optical system, and FIG.

FIG. 3 is an enlarged cross-sectional view of a main part of the molded object for explaining an embodiment of the optical molding method according to the present invention.

FIG. 4 is a configuration diagram of a reflection optical system showing another embodiment of the optical shaping apparatus according to the present invention.

[Explanation of symbols]

 11 Modeling tank 13 Uncured resin liquid (uncured photocurable resin) 15 Laser beam scanning device 16 Laser light source 18 Controller 19 Three-dimensional CAD system 20, 40 Reflective optical system 21 First reflecting mirror 22 Second reflecting mirror 23, 24 Motor 25 Third reflector 26 Fourth reflector 30A, 30B Light scanning area 33 Seam 100 Laser beam q Cured layer

Claims (3)

(57) [Claims] 1. A rotatable first reflector (21) for reflecting light (100) from a light source (16) and scanning in a first scanning direction, and light from the first reflector (21). A reflecting optical system (20) having a rotatable second reflecting mirror (22) for reflecting in the second scanning direction orthogonal to the first scanning direction by reflecting (100); By the system (20), the light (100) from the light source (16)
Are scanned in the first and second scanning directions, and the uncured photocurable resin (1
3) selectively exposing to form a cured layer (q) of the photocurable resin, and sequentially laminating and unifying the cured layers (q) to form a three-dimensional object; A third reflecting mirror (25) and a fourth reflecting mirror (26) are provided as fixed reflecting mirrors so as to be symmetrical with respect to the rotation center axis (C ₂ ) of the reflecting mirror (22) and at a predetermined distance. The second scanning by reflecting the reflected light (100) of the second reflecting mirror (25) to an arbitrary fixed reflecting mirror among the third reflecting mirror (25) and the fourth reflecting mirror (26); An optical shaping apparatus characterized by performing scanning in a direction. 2. A plurality of sets of said third and fourth reflecting mirrors (25, 26) are arranged in parallel in said second scanning direction, and said set of third and fourth reflections from said light source (16). 2. An optical shaping apparatus according to claim 1, further comprising switching means for switching a light projecting path to said mirror. 3. A stereolithography method using the stereolithography apparatus according to claim 1, wherein when laminating the next cured layer (q) on the already formed lower cured layer (q), The rotation range of the second reflection mirror (22) for scanning the light (100) from the reflection mirror (21) is changed to a range different from that when the lower hardened layer (q) is formed, and 3 reflectors (25)
Is shifted in the second scanning direction from the position where the lower hardened layer (q) is formed, between the optical scanning area (30A) using the third reflective mirror (26) and the optical scanning area (30B) using the fourth reflecting mirror (26). A stereolithography method characterized in that: