JP4519275B2 - Stereolithography apparatus and stereolithography method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical modeling apparatus and an optical modeling method for creating a mask, subjecting a photocurable resin to surface exposure according to a mask pattern, and performing optical modeling.
[0002]
[Prior art]
In general, an optical modeling apparatus that includes a control unit such as a three-dimensional CAD that outputs data related to optical modeling, and performs optical modeling by exposing a photocurable resin with a laser beam such as a semiconductor laser according to data from the control unit. It has been known.
[0003]
Since this type of resin takes a long time to expose and cure a single layer of resin, in recent years, a mask has been created for the purpose of high-speed modeling, and a photocurable resin is surface-exposed with a UV lamp in accordance with this mask pattern. Has been proposed.
[0004]
This surface exposure apparatus forms a mask using an electrostatic toner on a light transmissive member, superimposes it on an uncured resin layer, and irradiates ultraviolet light through the mask to apply the photocurable resin at once. Surface exposure is performed.
[0005]
[Problems to be solved by the invention]
However, in the conventional configuration, since the mask is overlaid on the uncured resin layer and the ultraviolet light is irradiated through the mask, the light must be parallel light.
[0006]
In order to produce this parallel light, the use of a grid has been proposed in the past. However, when this grid is used, the amount of light is reduced by about 10%, and there is a problem that the curing time becomes about 10 times longer.
[0007]
Further, if the output of the light source is increased, the curing time can be shortened. However, in this case, there is a problem that the power used increases and the running cost increases.
[0008]
As this light source, a mercury lamp, a metal halide lamp, an ultraviolet fluorescent lamp or the like is generally used. When this light source is used, the light source is always turned on, and exposure and shading control are performed using a shutter. Is called.
[0009]
However, since the amount of heat generated by the light source is large and the ambient temperature of the apparatus is significantly increased, a cooling device is required, and in particular, the heat causes deformation of the shutter, resulting in malfunction. is there.
[0010]
Further, in the conventional configuration, when the photo-curing resin is subjected to the collective surface exposure, distortion due to the curing shrinkage of the photo-curing resin is generated, and the modeling accuracy is lower than that of the linear exposure with the laser light. There is a problem.
[0011]
Therefore, the object of the present invention is to solve the problems of the prior art, to perform surface exposure with a simple configuration without using a grid or the like, to suppress the heat generation amount of the light source, and to form An object of the present invention is to provide an optical modeling apparatus and an optical modeling method in which accuracy does not decrease.
[0012]
[Means for Solving the Problems]
  According to the first aspect of the present invention, a mask to be subjected to surface exposure is created according to data for one layer relating to modeling, an uncured resin layer of a photocurable resin is surface exposed through the mask, and this surface exposure operation is performed. In an optical modeling apparatus that performs optical modeling by repeating,Exposure light source, lens,Arrange the Fresnel lens, the created mask, the projection lens, and the uncured resin layer in this order.The light from the exposure light source is spread over the entire area of the mask by the lens.Forming an optical system, exposing the uncured resin layer of the photocurable resin through the mask using the optical system, and the mask includes a plurality of mask patterns;Irradiate the light of the exposure light source each time each mask pattern is created on the mask,Surface exposure is performed in accordance with the data for one layer in a plurality of times using a plurality of mask patterns.
[0020]
  Claim2The described invention is claimed.1In the description, the mask is formed of a liquid crystal element, and the plurality of mask patterns are sequentially formed by controlling the liquid crystal element.
[0021]
  Claim3The described invention is claimed.1 or 2The exposure light source is a strobe.
[0023]
  Claim4The described invention creates a mask to be subjected to surface exposure according to the data for one layer relating to the optical modeling, exposes the uncured resin layer of the photocurable resin through the mask, and repeats this surface exposure operation. An optical modeling method for optical modeling withExposure light source, lens,Arrange the Fresnel lens, the created mask, the projection lens, and the uncured resin layer in this order.The light of the exposure light source is spread over the entire area of the mask by the lens, and the uncured resin layer of the photocurable resin is projected and exposed through the mask.Forming an optical system, wherein the mask includes a plurality of mask patterns;Irradiate the light of the exposure light source each time each mask pattern is created on the mask,Surface exposure is performed in accordance with the data for one layer in a plurality of times using a plurality of mask patterns.
[0024]
  Claim5The described invention is claimed.3In the description, the mask is formed of a liquid crystal element, and the plurality of mask patterns are sequentially formed by controlling the liquid crystal element.
[0025]
  Claim6The described invention is claimed.4 or 5The exposure light source is a strobe.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0027]
In FIG. 1, reference numeral 1 denotes an optical modeling apparatus. This stereolithography apparatus 1 includes a modeling stage A arranged at the lower stage of the apparatus, a mask creation stage B arranged at the upper stage of the apparatus, and a supply stage of a photocurable resin arranged on the left side of the modeling stage A in the drawing. C.
[0028]
This stereolithography apparatus 1 is provided with a control means (not shown) composed of a three-dimensional CAD or the like. In the mask creation stage B in the upper stage of the apparatus, a mask is created on the light transmissive member (glass) according to the data for one layer relating to the optical shaping from the control means. In addition, the supply stage C includes a unit D for resin supply, and the unit D moves to the modeling stage A to apply one layer of photocurable resin on the modeling object located there, An uncured resin layer is formed.
[0029]
The modeling stage A and the mask creation stage B (exposure stage F, which will be described later) are separated from each other by a predetermined distance, and the uncured resin layer at the lower stage of the apparatus is surface-exposed through the mask using the optical system of the projector which will be described later. Stereolithography is performed.
[0030]
The modeling stage A includes a modeling table 3 as shown in FIG. The modeling table 3 is connected to a foundation 5 by superposing two substantially X-shaped expansion / contraction links 4, and an output shaft of a servo motor 6 is connected to the expansion / contraction link 4. And the expansion link 4 is contracted by the drive of the servo motor 6, and the modeling table 3 is configured to be lowered and controlled every one minute.
[0031]
A stainless steel plate is affixed to the upper surface of the modeling table 3, and a first-layer uncured resin layer described later is directly applied to the upper surface.
[0032]
On the modeling table 3, a model is optically modeled. As an optical modeling procedure, first, the unit D located on the supply stage C is driven, and an uncured resin layer for one layer is formed on the modeling table 3 (or modeled object).
[0033]
This unit D is connected to the timing belt 7. The timing belt 7 is stretched between a pair of sprockets 8 and 9, and another timing belt 10 is stretched on one sprocket 9, and this timing belt 10 is stretched on a sprocket 12 of a drive motor 11. ing.
[0034]
Accordingly, by rotating the drive motor 11 forward and backward, the unit D is moved left and right in the drawing along the timing belt 7.
[0035]
The unit D stores a photocurable resin and has a resin supply dipper 14 for supplying the resin at the time of layer formation, a coating blade 15 for leveling the liquid level of the applied resin, and light transmittance. A peeling / sticking roller 16 is provided for peeling the polyester film 17 from the resin layer or sticking it to the resin layer. The polyester film 17 is stretched from one end 3a to the other end 3b with the modeling table 3 interposed therebetween. A roller 19 with a torque limiter is installed outside the one end 3 a of the modeling table 3, and one end 17 a of the film 17 is wound around the roller 19. The other end 17 b of the film 17 passes through the roller 21, the peeling and tensioning roller 16, and the roller 22, and is then wound around the roller 23 a of the film stretching motor 23. A tension roller 24 is connected to a rod of the air cylinder 25 and is urged in a direction to apply tension to the film 17.
[0036]
Next, the operation of the unit D will be described.
[0037]
When the upper right drive motor 11 in FIG. 2 is driven to rotate forward, the unit D is transferred along the timing belt 7 from the position shown in FIG. 2 to the position shown in FIG.
[0038]
In this transfer process, first, the film 17 is peeled from the resin layer while the film 17 is pressed by the peeling / tensioning roller 16. In this way, the film 17 is peeled off while being held down by the sticking roller 16, so that the resin layer stuck to the film 17 is not peeled off from the modeling table 3 together. When the film 17 is peeled off, some resin may stick to the lower surface of the film 17. This resin is removed by the blade 20 provided in the unit D.
[0039]
At the same time as the film 17 is peeled off, new resin is supplied from the resin supply dipper 14 on the modeled object, and a new uncured resin layer is formed.
[0040]
When the unit D is transferred by the timing belt 7 and reaches the right end in the figure, the modeling table 3 is lowered by the thickness of one resin layer.
[0041]
Next, the drive motor 11 is driven to rotate in the reverse direction, and the unit D is returned along the timing belt 7 from the position shown in FIG. In this reverse transfer process, first, the coating blade 15 removes excess resin, flattens the level of the resin liquid surface, and then the film 17 is pressed while being pressed by the peeling / stretching roller 16. It is pasted. According to this, the resin liquid level is held at a predetermined height, and after the film 17 is attached, the resin is held at that position.
[0042]
In short, the film 17 is stretched to hold the resin. Therefore, as long as the function is maintained, it is not limited to the film 17, and may be, for example, a sheet having light transmittance.
[0043]
In the above process, the film 17 is damaged. For example, when the thickness of the resin forming layer on the modeling table 3 is thin, the film 17 contacts the corner of the modeling table 3 and is damaged thereby. Therefore, when the film 17 is damaged, the re-covering motor 23 located at the left end in FIG. 2 is driven, and the film 17 wound around the roller 19 with a torque limiter is fed out. Be changed.
[0044]
In the movement range of the unit D, the resin supplied from the resin supply dipper 14 may droop.
[0045]
In order to collect this resin, tanks 27, 28, and 29 are installed so as to cover almost the entire area below the moving range of unit D, and the resin collected in these tanks 27, 28, and 29 is collected in return tank 30. Is done. Resin is stored in the return tank 30, and the resin is supplied to the resin supply dipper 14 through a supply system (not shown) as necessary.
[0046]
In the modeling stage A, when the film 17 is stretched on the uncured resin layer, the pressing glass 108 (FIG. 1) is closely attached and disposed thereon.
[0047]
As shown in FIG. 1, the mask creation stage B includes a mask creation unit 41, and a mask using toner is created on the light transmissive member (glass) 31 using the mask creation unit 41.
[0048]
The mask creating means 41 includes a demagnetizing head 42, a toner scraper 43, a charging head 44, and a developing device 45. The charging head 44 is controlled according to data for one layer output from a control means (not shown). . The mask creating means 41 is placed on a gantry 46, and the gantry 46 is hinged to a fixed portion of the apparatus by a pin 46a. The mask creating means 41 can be moved up and down with the pin 46a as a fulcrum. . The toner scraper 43 is covered with a cover 47, and a toner suction hose 48 is connected to the cover 47.
[0049]
It is desirable to mix silicon oxide, aluminum oxide, titanium oxide or the like as the UV absorbing material in the toner here. The UV absorption rate is 10% or more, preferably 30% or more, more preferably 50% or more.
[0050]
For the measurement of the mask creation stage B, a light transmissive member standby stage E is provided, and the glass 31 reciprocates between the light transmissive member standby stage E, the mask creation stage B, and the exposure table F in that order. .
[0051]
That is, between the light transmitting member standby stage E, the mask making stage B, and the exposure table F, a pair of rotationally driven belts 33 extend in two rows. The belt 33 is stretched between pulleys 34 and 35, and a pulley 37 a of a drive motor 37 is connected to one pulley 35 via a belt 36.
[0052]
A protrusion (not shown) on the lower surface of the glass 31 is hooked on the belt 33. Therefore, when the drive motor 37 is rotated forward and backward, the belt 33 moves in the forward and reverse directions, whereby the glass 31 is moved to each direction. Reciprocate between stages.
[0053]
A single actuating bar 38 is installed across the above stages E, B, and F. Stoppers 39 and 40 are fixed to both ends of the operation bar 38. When the glass 31 enters the light transmissive member standby stage E and comes into contact with the stopper 40 (as shown in FIG. 1), it is pushed by the glass 31 and the operating bar 38 moves to the right in the drawing. . Then, the cam member 51 fixed in the middle of the operation bar 38 moves to the right in the drawing together with the operation bar 38, and the mask creating means 41 is moved by the inclined cam surface 51a of the cam member 51. The base 46 is flipped up in the direction of the arrow X with the pin 46a as a fulcrum.
[0054]
On the other hand, when the glass 31 enters the exposure stage F and comes into contact with the stopper 39, it is pushed by the glass 31 and the operating bar 38 moves to the left (in the direction of arrow Z) in the drawing. Then, the cam member 51 fixed in the middle of the actuating bar 38 moves to the left in the figure together with the actuating bar 38, and the mask creating means is moved along the inclined cam surface 51 a of the cam member 51. 41 descends with the mount 46 in the direction of arrow Y to the mask creation position with the pin 46a as a fulcrum.
[0055]
Next, an operation for creating a mask on the glass 31 will be described.
[0056]
This mask is created in the process in which the glass 31 is sent from the exposure stage F to the light transmitting member standby stage E side. In this case, as described above, the mask creation means 41 is lowered to the mask creation position.
[0057]
When the glass 31 enters the mask making stage B, first, the surface of the glass 31 is demagnetized by the demagnetizing head 42 and the toner for the previous time is removed by the toner scraper 43. Next, the charging head 44 is controlled according to the data for one layer output from the control means (not shown), and the surface of the glass 31 is charged according to the data for that one layer. Then, after the toner is put on the developing unit 45 and a mask is formed on the glass surface, it is sent to the light transmitting member standby stage E.
[0058]
When the glass 31 is sent to the light transmissive member standby stage E, the mask creating means 41 is flipped up as described above, and a gap is formed below it. When the glass 31 on which the mask is created is sent from the transparent member standby stage E to the exposure stage F, it is sent through the gap. When the glass 31 is sent to the exposure stage F and comes into contact with the stopper 39, as described above, the mask creating means 41 is lowered to the mask creating position and stands by there.
[0059]
Above the exposure stage F, as shown in FIG. 1, an exposure device (lighting fixture) 53 for exposing the photocurable resin to the surface through the mask of the glass 31 is provided. The exposure device 53 contains a light source such as a mercury lamp, a metal halide lamp, or an ultraviolet fluorescent lamp.
[0060]
The light from the exposure device 53 passes through the glass 31 and travels inside the fixed cover member 54 extending below the exposure stage F, and the shutter 99, the project lens 101 described later, and the fixed hood telescopic hood 55. Then, the light curable resin is surface-exposed through the pressing glass 108.
[0061]
As shown in FIG. 4, the hood 55 is suspended by a wire 56, and the wire 56 is connected to a winding pulley 58 through a fixed pulley 57. A belt 59 is hung on the winding pulley 58, and the belt 59 is hung on a pulley 61 fixed to the output shaft of the motor 60.
[0062]
In this embodiment, the hood 55 can be moved up and down as shown in FIGS. 4 and 5 by rotating the motor 60 forward and backward.
[0063]
When the hood 55 descends and the hood 55 covers the pressing glass 108 and the resin as shown in FIG. 5, the hood 55 and the pressing glass 108 are positioned on the modeling stage A as described later. 4 to 5, reference numeral 63 denotes a guide post.
[0064]
With reference to FIG. 4, a pair of cylinders 71 and 72 are disposed under the modeling table 3. A horizontal bar 73 is connected to the rods of the cylinders 71 and 72, and a pair of operation rods 74 and 75 extending vertically upward are connected to both ends of the horizontal bar 73 so as to be rotatable about the axis. A sleeve 76 is fixed to the outer periphery of each operation rod 74, 75, and a lead groove 76 a is formed on the outer periphery of the sleeve 76. The lead groove 76a extends in a spiral shape, and a pin 77 fixed to the fixing member 78 is fitted into the lead groove 76a.
[0065]
The pressing glass 108 is held by the guide rail 67 and is carried onto the modeling table 3 from the direction of the arrow X shown in FIG. When the pressing glass 108 is stacked on the film 17, the modeling table 3 is controlled to be lowered by one layer, and then the hood 55 is lowered as shown in FIG.
[0066]
When the lower end 55a of the hood 55 comes into contact with the pressing glass 108, as shown in FIG. 5, the rods of the cylinders 71 and 72 are extended, the horizontal bar 73 is pushed down, and the pair of operation rods 74 and 75 are integrally formed. Descent.
[0067]
In the descending process, the operating rods 74 and 75 rotate around the axis along the shape of the lead groove 76a, and the stators 74a and 75a at the upper ends of the operating rods 74 and 75 are positioned as shown in FIGS. The projections 103 of the stators 74a and 75a push down the lower end 55b of the hood 55 and fix it.
[0068]
When one layer of optical modeling at the modeling stage A is completed, the glass 31 is sent to the mask creation stage B as described above.
[0069]
In this embodiment, as shown in FIG. 6, the light transmissive member 31 and the uncured resin layer 96 are arranged at a predetermined distance L1, and the uncured resin layer 96 of the photocurable resin is projected and exposed through the mask. An optical system 90 is provided. The optical system 90 includes a reflecting mirror 91, a metal halide lamp (lighting fixture) 92, a lens 93 for spreading light from the metal halide lamp 92 over the entire area of the glass 31, a Fresnel lens 94, the glass 31, and a shutter. 99, the projection lens 101, and the uncured resin layer 96 are arranged in this order. As described above, the uncured resin layer 96 is a resin layer made of a photocurable resin that is sequentially formed on the modeling table 3. Note that the Fresnel lens 94 can be omitted.
[0070]
The procedure of stereolithography using this apparatus will be described. First, referring to FIG. 1, a toner mask is formed on a glass 31 according to data from a control means (not shown) by three-dimensional CAD, and this glass 31 is exposed to an exposure stage. While being carried into F, an uncured resin layer 96 is formed on the modeling table 3.
[0071]
Referring to FIG. 6, metal halide lamp 92 is always on. Light from the metal halide lamp 92 enters the lens 93 and is spread by the lens 93 over the entire area of the Fresnel lens 94 and the glass 31. The Fresnel lens 94 improves the light collection efficiency.
[0072]
Next, when the shutter 99 is opened, the light from the metal halide lamp 92 enters the projection lens (focusing means) 101, and focusing is performed through the projection lens 101. The uncured resin layer 96 is exposed by the light transmitted through the portion. The above-described exposure operation is repeated to perform stereolithography.
[0073]
In this embodiment, unlike the conventional configuration, a grid for generating parallel light is not required, so that the amount of light reaching the uncured resin layer 96 is not reduced, and the curing time is shortened.
[0074]
FIG. 7 shows another embodiment of the optical system.
[0075]
In this embodiment, the optically transparent member 31 and the uncured resin layer 96 are arranged with a predetermined distance L2 apart from each other, and an optical system 80 for projecting and exposing the uncured resin layer 96 of the photocurable resin through the mask is provided. . The optical system 80 includes a reflecting mirror 81, a metal halide lamp (lighting fixture) 82, a lens 83 for spreading light from the metal halide lamp 82, a shutter 89, a Fresnel lens 84, a glass 31, and an uncured material. The resin layers 96 are arranged in this order.
[0076]
As described above, the uncured resin layer 96 is a resin layer made of a photocurable resin that is sequentially formed on the modeling table 3.
[0077]
The metal halide lamp 82 is always lit. The light from the metal halide lamp 82 enters the lens 83 when the shutter 89 is opened, and is spread over the entire area of the Fresnel lens 84 by the lens 83. The Fresnel lens 84 forms parallel light, and the parallel light passing through the Fresnel lens 84 exposes the uncured resin layer 96 through the mask of the glass 31.
[0078]
These lenses 83 and 84 constitute a member for forming parallel light. However, the present invention is not limited to this structure. For example, it is obvious that parallel light may be formed by a combination of mirrors or the like.
[0079]
In this embodiment, unlike the conventional configuration, a grid for generating parallel light is not required, so that the amount of light reaching the uncured resin layer 96 is not reduced, and the curing time is shortened.
[0080]
Next, data correction performed at the time of mask creation will be described.
[0081]
When performing projection exposure using the above optical system, as shown in FIG. 8a, for example, if it is desired to obtain a regular square, and projection exposure is performed with the data as it is, distortion occurs as shown in FIG. The peripheral shape is distorted.
[0082]
Therefore, if the data used when creating the mask is corrected in advance by curving the four sides as shown in FIG. 8c, projection exposure is performed based on the corrected data, as shown in FIG. 8d. The original regular square shape is obtained on the uncured resin layer 96.
[0083]
This will be described according to the processing flow of FIG. 9. First, contour shape data corresponding to FIG. 8a is obtained (S1), and coordinates (X1, Y1) (X2, Y2) are calculated from this data (S2). The correction values (X1 ′, Y1 ′) (X2 ′, Y2 ′) shown in FIG. 8b, which are stored in the correction position database in advance, are assigned to the calculated coordinates (S3), and the correction shape data shown in FIG. (X1 ″, Y1 ″) (X2 ″, Y2 ″) is obtained (S4).
[0084]
Next, it is checked whether or not there is another data (S5). As long as there is another data, S1 to S4 are repeated, and when there is no more data, the portion surrounded by the outline is painted ( S6). By performing projection exposure based on the corrected data thus obtained, an original regular square shape is obtained on the uncured resin layer 96, as shown in FIG. 8d.
[0085]
FIG. 10 shows a processing flow according to another embodiment. The processing shown in FIG. 9 obtains the contour shape and fills the inside of the frame surrounded by these to obtain data, whereas in the present embodiment, processing is performed using a bitmap. Shape data corresponding to FIG. 8a is obtained from point cloud data (S11), and coordinates (X1, Y1) (X2, Y2) are calculated from this data (S12). The correction values (X1 ′, Y1 ′) (X2 ′, Y2 ′) shown in FIG. 8b, which are stored in the correction position database in advance, are assigned to the calculated coordinates (S13), and the correction shape data shown in FIG. 8c. (X1 ″, Y1 ″) (X2 ″, Y2 ″) is obtained (S14).
[0086]
Next, it is checked whether or not there is another data (S15), and S11 to S14 are repeated until there is no more data.
[0087]
According to this, although the steps of S11 to S14 require processing time for the point group, projection exposure is performed based on the corrected data obtained in this way, as in the above embodiment. As shown in FIG. 8 d, a regular square shape can be obtained on the uncured resin layer 96.
[0088]
FIG. 11 shows another embodiment.
[0089]
This embodiment is different from the apparatus shown in FIG. 6 in that the light source 192 is composed of a strobe. The second difference is that a mask made of a light transmissive member is composed of a liquid crystal mask 131. However, when the liquid crystal mask 131 is used, the mask 131 is fixed on the exposure table F, unlike the one shown in FIG.
[0090]
In FIG. 11, a mask 131 and an uncured resin layer 96 are arranged with a predetermined distance L1 therebetween, and an optical system 90 for projecting and exposing the uncured resin layer 96 of a photocurable resin through the mask is provided. The optical system 90 includes a reflecting mirror 91, a strobe light source (lighting fixture) 92, a lens 93 for spreading light from the strobe light source 92 over the entire area of the glass 31, a Fresnel lens 94, a mask 131, and a projection. The lens 101 and the uncured resin layer 96 are arranged in this order.
[0091]
In this case, the shutter used in FIG. 6 becomes unnecessary. 192A is a charging / discharging device, and 123 is a control device for controlling the liquid crystal mask. The uncured resin layer 96 is a resin layer made of a photocurable resin that is sequentially formed on the modeling table 3. Note that the Fresnel lens 94 can be omitted.
[0092]
In this embodiment, since the strobe light source 192 is used, a shutter is not necessary and the amount of heat generated by the light source 192 is suppressed. Accordingly, a very large cooling device is not necessary, and naturally, problems such as a malfunction of the shutter due to deformation of the shutter are solved. Further, since the heat generation amount of the light source 192 is reduced, the thermal effect on the uncured resin layer 96 is eliminated.
[0093]
Although illustration is omitted, it is needless to say that the strobe light source and the liquid crystal mask can be adopted for the apparatus corresponding to FIG.
[0094]
In the present embodiment, as shown in FIG. 11, a control device 123 connected to the liquid crystal mask 131 is provided. The control device 123 includes a three-dimensional CAD and the like, and outputs cross-sectional data for one layer obtained by thinly slicing a three-dimensional model to be formed, for example, in the horizontal direction, and creates a mask based on the output data.
[0095]
When the control device 123 operates, a predetermined voltage according to data for one layer is applied to the liquid crystal elements constituting the mask 131.
[0096]
In FIG. 12, for example, the liquid crystal element constituting the mask 131 has a plurality of electrodes (not shown) extending in the X direction and the Y direction. Formed at the intersection.
[0097]
In the present embodiment, when the data for one layer is cross-sectional data representing a rectangle of length L1 and width L2 in FIG. 12, it is divided into two times according to the two types of mask patterns shown in FIGS. 12a and 12b. Then, the resin is cured according to the cross-sectional data representing the rectangle. In FIG. 12, diagonal lines indicate a portion 100 that blocks light, and white portions indicate a portion 200 that transmits light.
[0098]
That is, the control device 123 operates and the voltages applied to the plurality of electrodes are controlled. First, as shown in FIG. 12A, a central portion 200 is formed to transmit light, and light is shielded around it. A portion 100 is formed.
[0099]
In this state, the strobe light source 192 is turned on. Then, light reaches the uncured resin layer 96 in the central portion through the light transmitting portion 200, and the uncured resin layer 96 corresponding to the portion 200 is cured.
[0100]
Next, the control device 123 operates, and as shown in FIG. 12b, a portion 100 that shields light is formed at the central portion, and a portion 200 that transmits light is formed around it. In this state, the strobe light source 192 is turned on. Then, light reaches the uncured resin layer 96 in the peripheral portion through the light transmitting portion 200, and the uncured resin layer 96 corresponding to the portion 200 is cured.
[0101]
When the light transmission parts 200 shown in FIGS. 12a and 12b are overlapped, the exposure range according to the cross-sectional data representing the rectangles L1 and L2 coincides.
[0102]
In the above configuration, when the uncured resin layer 96 is cured according to the cross-sectional data representing the rectangles L1 and L2, the surface exposure is performed in two steps according to the two types of mask patterns shown in FIGS. 12a and 12b. Compared with the case where the uncured resin layer 96 according to the cross-sectional data representing the rectangles L1 and L2 is subjected to surface exposure at a time, generation of distortion due to curing shrinkage of the photocurable resin is suppressed.
[0103]
Therefore, for example, the modeling accuracy can be maintained to the same extent as that of the conventional one exposed with laser light.
[0104]
Various mask patterns are proposed. For example, as shown in FIGS. 13a and 13b, when an exposure range is set according to cross-sectional data representing rectangles of length L1 and width L2, the mask pattern includes a portion 100 that blocks light and a portion that transmits light. 200 is formed in a checkered pattern. In the mask patterns shown in FIGS. 14A and 14B, a light shielding portion 100 and a light transmitting portion 200 are formed in a strip pattern. In these cases as well, when the light transmission portions 200 shown in the drawings are overlapped, the exposure range conforms to the cross-sectional data representing the rectangle.
[0105]
When the mask patterns shown in FIGS. 15a to 15c are used, the surface exposure is performed in three steps. In FIG. 15a, first, exposure is performed using the cross-shaped light transmission portion 200, and in FIG. 15b, exposure is performed using the light transmission portion 200 having a shape excluding the four corners among the remaining portions. Exposure is performed using the light transmitting portions 200 at the four corners.
[0106]
When the mask patterns shown in FIGS. 16a to 16d are used, the surface exposure is divided into four times. In this case, in FIG. 16a, first, exposure is performed using the light transmission portion 200 having a central rectangular shape, and in FIG. 16b and thereafter, the light transmission portion 200 in which the rectangular shape is gradually expanded is used except for the already exposed portion. To expose. When the mask patterns shown in FIGS. 17a to 17d are used, the surface exposure is divided into four times, and when the patterns shown in FIGS. 18a to 18h are used, the surface exposure is divided into eight times, and FIGS. When the pattern shown in FIG. 19c is used, the surface exposure is divided into three times.
[0107]
In any case, when the light transmission portions 200 shown in each figure are overlaid, the exposure range conforms to the cross-sectional data representing the rectangle.
[0108]
When the mask patterns shown in FIGS. 20a to 20d are used, the surface exposure is performed four times. In this case, when the light transmissive portions 200 shown in FIGS. 20a and 20b are overlapped, the exposure range according to the cross-sectional data representing the rectangle is matched, and when the light transmissive portions 200 shown in FIGS. This coincides with the exposure range according to the cross-sectional data representing. According to this, since the original exposure range is exposed twice, one exposure time is set to half the exposure time.
[0109]
12 to 19, for example, if the exposure time using each mask pattern is set to 3 to 5 seconds, the exposure time using each mask pattern in FIG. 20 is 1.5 to 2.5 seconds. Set to
[0110]
In any embodiment, when the uncured resin layer 96 is cured according to the cross-sectional data representing the rectangles L1 and L2, the surface is divided partially or stepwise according to a plurality of types of mask patterns. Since the exposure is performed, the occurrence of distortion due to curing shrinkage of the photocurable resin is suppressed as compared with the case where the uncured resin layer 96 according to the cross-sectional data representing the rectangles L1 and L2 is exposed at a time.
[0111]
Therefore, as described above, the modeling accuracy can be maintained to the same extent as the conventional one that is exposed with laser light.
[0112]
FIG. 21 shows a flow of creating the mask pattern.
[0113]
S1 to S3 are procedures for creating the cross-sectional data for one layer. Data from a three-dimensional CAD or the like is read (S1), and this data is sliced to create the cross-sectional data (S2). And the data regarding a support (member which supports a molded article during modeling) is provided to this cross-sectional data (S3).
[0114]
Next, it is determined whether or not the number of layers of the modeled object (model) has been completed (S4). If not, the model and support fill data (cross-sectional data for one layer) is calculated and stored. (S5). Next, when the first mask pattern (for example, FIG. 12a) is used, a fill pattern is calculated and stored (S6), and a logical product of the model and support and the mask pattern is calculated to create a mask. Perform (S7) and expose (S8).
[0115]
Further, it is determined whether or not the mask pattern has been completed (S9). If it has not been completed, the process proceeds to S6, and the fill pattern when the second mask pattern (for example, FIG. 12b) is used is determined. Based on this calculation, a mask is created based on this, and exposure is performed (S8).
[0116]
When the mask pattern is completed in S9, the process proceeds to S4 to create a mask for the next layer and execute exposure.
[0117]
When these processes proceed and the number of model stacks is completed in S4, the process proceeds to S10 and the optical modeling is completed.
[0118]
According to the present embodiment, the surface exposure is performed in a plurality of times and partially or stepwise, so that the occurrence of distortion due to the curing shrinkage of the photocurable resin as compared with the conventional case where the surface exposure is performed at once. Can be suppressed.
[0119]
As mentioned above, although this invention was demonstrated based on one Embodiment, it is clear that this invention is not limited to this.
[0120]
For example, in the above-described embodiment, the optical modeling in which the modeled object is stacked and modeled up and down has been described. However, when the modeled object is enlarged, the model is stacked in the horizontal direction and optically modeled without being stacked up and down. Is possible. In this case, it goes without saying that the optical system is also arranged in the horizontal direction.
[0121]
【The invention's effect】
According to the present invention, light energy can be made to reach the resin exposure surface efficiently, accurately, and inexpensively. Moreover, the calorific value of a light source can be suppressed and modeling accuracy can be improved.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of an optical modeling apparatus according to the present invention.
FIG. 2 is a front view showing a modeling stage.
FIG. 3 is a front view showing movement of a unit.
FIG. 4 is a front view showing positioning on a modeling stage.
FIG. 5 is a front view of the lighting device with the hood lowered.
FIG. 6 is a perspective view showing an optical system.
FIG. 7 is a perspective view showing another embodiment of the optical system.
FIG. 8 is a diagram illustrating data correction.
FIG. 9 is a flowchart of an embodiment.
FIG. 10 is a flowchart of another embodiment.
FIG. 11 is a view corresponding to FIG. 6 showing another embodiment.
FIGS. 12A and 12B are diagrams showing mask patterns, respectively.
FIGS. 13A and 13B are diagrams showing mask patterns, respectively.
FIGS. 14A and 14B are diagrams showing mask patterns, respectively.
FIGS. 15A to 15C are diagrams showing mask patterns, respectively.
16A to 16D are diagrams showing mask patterns, respectively.
FIGS. 17A to 17D are diagrams showing mask patterns, respectively. FIGS.
18A to 18H are diagrams showing mask patterns, respectively.
19A to 19C are diagrams showing mask patterns, respectively.
20A to 20D are diagrams showing mask patterns, respectively.
FIG. 21 is a flowchart showing a mask creation procedure;
[Explanation of symbols]
1 Stereolithography equipment
3 Modeling table
14 Resin supply dipper
31 glass
41 Mask making means
53 Exposure equipment
80,90 optical system
81,91 Reflector
82,92 Metal halide lamps (lighting fixtures)
84,94 Fresnel lens
96 Uncured resin layer
89,99 Shutter
101 Projection lens
131 LCD mask
123 Controller
192 Strobe light source
192A Charge / Discharge Device

Claims (6)

The light to be subjected to optical modeling by creating a mask for surface exposure according to the data for one layer related to optical modeling, surface-exposing the uncured resin layer of the photocurable resin through this mask, and repeating this surface exposure operation In modeling equipment,
An exposure light source, a lens, a Fresnel lens, the created mask, a projection lens, and the uncured resin layer are arranged in this order, and an optical system that spreads the light of the exposure light source over the entire area of the mask is formed by the lens,
Exposing the uncured resin layer of the photocurable resin through the mask using this optical system,
The mask includes a plurality of mask patterns, and each time the mask pattern is formed on the mask, the light from the exposure light source is irradiated, and the plurality of mask patterns are used to divide the mask into a plurality of times and follow the data for the one layer. An optical modeling apparatus that performs surface exposure.   The stereolithography apparatus according to claim 1, wherein the mask includes a liquid crystal element, and the plurality of mask patterns are sequentially formed by controlling the liquid crystal element.   The stereolithography apparatus according to claim 1, wherein the exposure light source is a strobe. The light to be subjected to optical modeling by creating a mask for surface exposure according to the data for one layer related to optical modeling, surface-exposing the uncured resin layer of the photocurable resin through this mask, and repeating this surface exposure operation A modeling method,
An exposure light source, a lens, a Fresnel lens, the created mask, a projection lens, and the uncured resin layer are arranged in this order, and the light from the exposure light source is spread over the entire area of the mask by the lens, and photocured through the mask. Forming an optical system that projects and exposes an uncured resin layer of a functional resin ,
The mask includes a plurality of mask patterns, and each time the mask pattern is formed on the mask, the light from the exposure light source is irradiated, and the plurality of mask patterns are used to divide the mask into a plurality of times and follow the data for the one layer. An optical modeling method characterized by performing surface exposure.   5. The stereolithography method according to claim 4, wherein the mask is composed of a liquid crystal element, and the plurality of mask patterns are sequentially formed by controlling the liquid crystal element.   6. The stereolithography method according to claim 4, wherein the exposure light source is a strobe.

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