JPH0976353A - Optical shaping apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform highly precise shaping under the optimum shaping condition from the deformation or shrink stress of a photo-setting resin by using laser beam of smoothed intensity distribution and measuring the deformation or shrink stress generated when the photo-setting resin is cured within a real time. SOLUTION: A photo-setting resin is irradiated with laser beam and the deformation quantity and shrink stress of the linear cured substance thereof are detected by a deformation sensor 41 and a stress sensor 42 and it is evaluated and judged whether the shape error of the linear cured substance is within a tolerance value range on the basis of shaping data from these deformation quantity and shrink stress by a shaping condition judging means 67. As the result of evaluation and judgment, when the shape error is within the tolerance value range, shaping is executed by a shaping control means 68 and, when the shape error exceeds the tolerance value range, at least a shaping condition composed of the intensity of laser beam is altered by a shaping control means 68 to execute shaping.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocurable resin which is scanned with light, for example, a laser beam to cure the photocurable resin layer by layer, and the cured portions are laminated to form a three-dimensional shape. The present invention relates to a modeling device.

[0002]

2. Description of the Related Art Such a stereolithography apparatus uses a laser oscillator or a lamp as a light source and controls scanning of a laser beam or the like for irradiating a photocurable resin with an orthogonal plotter or a galvano mirror, and photocurable layer by layer. The resin is being cured.

The laser beam output from the laser oscillator is controlled in scanning position and is applied to the photocurable resin through the focus stop mechanism.

FIG. 23 is a block diagram of an orthogonal type stereolithography apparatus.

A resin container 1 stores a photocurable resin 2 such as an ultraviolet curable resin. In this resin container 1,
An elevator 3 is provided.

[0006] By the lifting operation of the elevator 3, the modeling base 4 is lowered by a distance corresponding to the thickness of the cured portion of one layer of the photocurable resin 2 when performing optical modeling.

Further, the laser oscillator 5 mainly oscillates laser using argon or He-Cd as a medium.
This is provided on the orthogonal plotter 6.

This orthogonal plotter 6 includes a laser oscillator 5
It has a function of irradiating the photocurable resin 2 with a laser beam output from the mirror 7 and controlling the scanning of the laser beam with respect to the photocurable resin 2.

With such a structure, the molding base 4 is arranged near the surface of the photocurable resin 2 by controlling the elevation of the elevator 3, and the laser beam output from the laser oscillator 5 is emitted by the orthogonal plotter 6. The surface of the curable resin 2 is scanned.

In this way, the laser beam is applied to the photocurable resin 2
When the laser beam is scanned, the photocurable resin 2 in the portion irradiated with the laser beam is cured, and this is formed as the cured portion 4a of the first layer.

Subsequently, the molding base 4 is lowered by the elevation control of the elevator 3, and the laser beam output from the oscillator 5 is scanned on the surface of the photocurable resin 2 by the orthogonal plotter 6, whereby the second layer is formed. The hardened part 4b is formed.

Thereafter, similarly, the modeling base 4 descends and the operation of scanning the surface of the photocurable resin 2 with the laser beam is repeated, and a desired three-dimensional shape is modeled.

FIG. 24 is a block diagram of a galvanometer mirror type optical modeling apparatus. The same parts as those in FIG. 23 are designated by the same reference numerals.

The laser beam output from the laser oscillator 5 is reflected by each of the mirrors 8 and 9 and sent to the galvano mirror 10, and the galvano mirror 10 causes the photocurable resin 2 to pass through.
Is to be scanned on the surface of.

With such a configuration, the molding base 4 is arranged near the surface of the photo-curable resin 2 by the elevation control of the elevator 3, and the laser beam output from the laser oscillator 5 is photo-cured by the galvano mirror 10. The surface of the resinous resin 2 is two-dimensionally scanned to form the cured portion 4a of the first layer.

Subsequently, the molding base 4 is lowered by the elevation control of the elevator 3, the laser beam output from the oscillator 5 is scanned on the surface of the photocurable resin 2 by the galvanometer mirror 10, and the cured portion of the second layer. 4b is formed.

Thereafter, similarly, the modeling base 4 descends and the operation of scanning the surface of the photocurable resin 2 with the laser beam is repeated, and a desired three-dimensional shape is modeled.

On the other hand, in the stereolithography apparatus, in order to perform high-precision stereolithography, molding conditions are set based on prior tests, experience, etc., and all molding is performed based on this.

The intensity of the laser beam applied to the photocurable resin 2 at the point of action is measured by a photosensor or the like,
By managing this, the output fluctuation of the laser oscillator 5 and the change of the loss of the optical system are dealt with.

Further, the deformation and shrinkage stress generated when the photocurable resin 2 is cured by irradiation with a laser beam are measured. This measurement is performed by an indirect method such as exposing and curing a photo-curable resin thinly applied on a thin sheet and measuring the deformation of the sheet at this time.

However, mainly argon or He-C
Since the laser beam output from the laser oscillator 5 having d as a medium is directly used for modeling, the two-dimensional intensity distribution of the laser beam with which the photocurable resin 2 is irradiated corresponds to the Gaussian distribution as shown in FIG. It will be done.

Since the photocurable resin 2 is scanned with the laser beam having the intensity distribution of the Gaussian distribution, the laser beams are applied so as to overlap each other as shown in FIG.

The following problems occur due to such a method of stereolithography.

(A) Since the laser beams are overlapped, the degree of curing of the photocurable resin 2 becomes uneven.

(B) An uncured portion remains.

(C) Strain is generated due to the non-uniform degree of hardening.

(D) Strain causes shape deformation.

On the other hand, in order to perform high-precision stereolithography, the intensity of the laser beam applied to the photocurable resin 2 at the point of action is measured by a photosensor or the like, which is managed and controlled. However, it is not possible to deal with changes in the curing characteristics based on the intensity distribution of the laser beam and the characteristics of the photocurable resin 2.

Further, although the deformation and contraction stress generated when the photocurable resin 2 is cured by the irradiation of the laser beam is indirectly measured using a thin sheet, these deformation and contraction stress are measured in real time. Not something to do.

[0030]

As described above, since the intensity distribution of the laser beam has a Gaussian distribution, there is a problem that the degree of curing of the photocurable resin 2 becomes uneven.

Further, it is impossible to measure in real time the deformation and shrinkage stress that occur when the photocurable resin 2 is cured.

Therefore, an object of the present invention is to provide an optical modeling apparatus capable of smoothing the intensity distribution of a laser beam and performing highly accurate modeling.

It is another object of the present invention to provide an optical molding apparatus capable of measuring in real time deformation and shrinkage stress that occur when the photocurable resin is cured.

Further, the present invention provides an optical modeling apparatus capable of measuring the deformation and shrinkage stress generated when the photocurable resin is cured in real time, and performing highly accurate modeling from these deformation and shrinkage stress under optimum modeling conditions. The purpose is to provide.

Further, according to the present invention, a laser beam having a smoothed intensity distribution is used, and the deformation or shrinkage stress generated when the photocurable resin is cured is measured in real time, and the optimum deformation or shrinkage stress is determined from these. It is an object of the present invention to provide an optical modeling apparatus that can perform highly accurate modeling under modeling conditions.

[0036]

According to a first aspect of the present invention, a photocurable resin is scanned with light to cure the photocurable resin, and the cured portions are laminated to form a three-dimensional shape. In the modeling apparatus, an optical modeling apparatus provided with a smoothing optical system that smoothes the intensity of light scanning a photocurable resin.

In such a stereolithography apparatus, since light having a smoothed intensity is scanned by the photocurable resin, overlapping of the light can be minimized and the degree of curing of the photocurable resin is uniform. Becomes

According to the second aspect of the present invention, in the optical molding apparatus for scanning the photo-curable resin with light to cure the photo-curable resin and stacking the cured parts to form a three-dimensional shape, A sensor that detects at least one of the deformation amount and the contraction stress in the cured portion of the resin, and the light based on the modeling data including at least the modeling accuracy preset from at least one of the deformation amount and the contraction stress detected by the sensor. An optical modeling apparatus including a modeling condition determining unit that determines whether or not a shape error of a cured portion of a curable resin is within an allowable value.

In such an optical molding apparatus, the photocurable resin is irradiated with light to detect at least one of the deformation amount and the contraction stress in the cured portion by the sensor, and the molding is performed based on the deformation amount or the contraction stress. Based on the data, it is evaluated whether the shape error of the cured portion of the photocurable resin is within the allowable value.

According to a third aspect of the present invention, the photo-curable resin is scanned by light to cure the photo-curable resin, and the cured portion is laminated to form a three-dimensional shape. A sensor that detects at least one of the deformation amount and the contraction stress in the cured portion of the resin, and the light based on the modeling data including at least the modeling accuracy preset from at least one of the deformation amount and the contraction stress detected by the sensor. The molding condition determining means for evaluating whether or not the shape error of the cured portion of the curable resin is within the allowable value, and the shape error of the cured portion of the photocurable resin is within the allowable value by this molding condition determining means. Modeling control means for performing modeling and changing the modeling conditions consisting of at least light intensity to perform modeling when the shape error of the cured portion of the photocurable resin exceeds the allowable value. It was an optical shaping apparatus.

In such an optical molding apparatus, the photocurable resin is irradiated with light to detect at least one of the deformation amount and the contraction stress in the cured portion by the sensor, and the molding is performed based on the deformation amount or the contraction stress. Based on the data, it is evaluated whether the shape error of the cured part of the photocurable resin is within the allowable value.As a result of this evaluation judgment, the shape error of the cured part of the photocurable resin is within the allowable value. For example, the molding is performed, and if the shape error of the cured portion of the photocurable resin exceeds the allowable value, the molding condition including at least the light intensity is changed to perform the modeling.

According to a fourth aspect of the present invention, in the optical molding apparatus for scanning a photo-curable resin with light to cure the photo-curable resin and stacking the cured parts to form a three-dimensional shape, A smoothing optical system that smoothes the intensity of the light scanning the resin, a sensor that detects at least one of the deformation amount and contraction stress in the cured portion of the photocurable resin, and the deformation amount or contraction detected by this sensor. Based on at least one of the preset modeling data from at least one of the stress, the molding condition determining means for evaluating whether or not the shape error of the cured portion of the photocurable resin is within the allowable value, and this molding condition determining means. If the shape error of the cured part of the photo-curable resin is within the allowable value, molding is performed, and if the shape error of the cured part of the photo-curable resin exceeds the allowable value, the molding conditions that consist of at least light intensity are set. A shaping control means for performing a shaped further to an optical shaping apparatus equipped with.

In such an optical modeling apparatus, light having a smoothed intensity distribution is applied to the photocurable resin, and at least one of the amount of deformation and shrinkage stress in the cured portion is detected by a sensor, and this deformation is performed. Based on the modeling data from the amount or shrinkage stress, it is evaluated whether the shape error of the cured portion of the photocurable resin is within the allowable value.As a result of this evaluation judgment, if the shape error is within the allowable value, When the modeling is performed, and if the shape error exceeds the allowable value, the modeling condition including at least the light intensity is changed to perform the modeling.

According to a fifth aspect, the smoothing optical system in the stereolithography apparatus according to the first or fourth aspect is formed by a kaleidoscope for smoothing light having an intensity distribution of Gaussian distribution.

According to a sixth aspect, the smoothing optical system in the stereolithography apparatus according to the first or fourth aspect is a kaleidoscope for smoothing light having a Gaussian distribution intensity distribution, and an output of the kaleidoscope. And a slit plate having a desired shape arranged on the end side.

According to a seventh aspect, the smoothing optical system in the stereolithography apparatus according to the first or fourth aspect includes a branching optical system for branching the light scanning the photocurable resin into a plurality of beams, and the branching optical system. Arranged on each optical path of each branched light, set on each light path of each light branched by the branch optical system, and a light shielding plate that sets the passage area of these lights, and set the intensity of these lights arbitrarily And a photosynthetic optical system that combines the light beams that have passed through the light-shielding plate and the filter into a light beam having a smoothed intensity distribution.

According to an eighth aspect of the present invention, in the stereolithography apparatus according to the second, third or fourth aspect, the deformation amount of the cured portion of the photocurable resin is detected by a deformation sensor to pull the cured portion of the photocurable resin. The force is detected by the stress sensor, and thereby the deformation information and the stress state of the cured portion of the photocurable resin are obtained.

According to the ninth aspect, the modeling condition determining means in the optical modeling apparatus according to the second, third or fourth aspect is characterized in that the deformation amount and the stress and the modeling accuracy obtained at least based on a basic modeling experiment or experience. The shape error of the cured portion of the photo-curable resin is within the allowable value based on the modeling data from at least one of the deformation amount and the contraction stress detected by the sensor, which holds the modeling data having the function or knowledge indicating the relationship of Whether or not is evaluated and judged.

According to the tenth aspect of the present invention, in the optical molding apparatus for scanning a photocurable resin with light to cure the photocurable resin and stacking the cured parts to form a three-dimensional shape, A sensor for detecting at least one of a deformation amount and a contraction stress in a cured portion of the resin, and at least a surface cured product from the deformation amount or the contraction stress detected by the sensor when the photocurable resin is planarly scanned with light. A deformation amount calculating means for obtaining a deformation amount, and a shape error of a cured portion of the photocurable resin is within an allowable value based on modeling data including at least modeling accuracy preset from the deformation amount calculated by the deformation amount calculating means. If the shape error of the cured portion of the photo-curable resin is within the allowable value by the molding condition determination means for evaluating whether or not A shaping control means for shape errors of the cured portion of the resin is carried out molding by changing the molding condition consisting of the intensity of at least a light if exceeds the allowable value, an optical shaping apparatus equipped with.

In such an optical modeling apparatus, the photocurable resin is irradiated with light to detect at least one of the deformation amount and the contraction stress in the cured portion by the sensor, and the detected deformation amount or contraction. At least the amount of deformation of the surface-cured product is obtained from the stress. Then, based on the modeling data from the deformation amount or the contraction stress, it is evaluated whether or not the shape error of the cured portion of the photocurable resin is within the allowable value, and as a result of this evaluation judgment, the shape error is the allowable value. If it is within the range, the modeling is performed, and if the shape error exceeds the allowable value, the modeling condition including at least the light intensity is changed to perform the modeling.

[0051]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. The same parts as those in FIG. 24 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a block diagram of the stereolithography apparatus.

A smoothing optical system 20 is arranged on the optical path of the light beam output from the laser oscillator 5.

This smoothing optical system 20 is composed of a photocurable resin 2
It has a function of smoothing the intensity of a laser beam having a Gaussian intensity distribution that scans to zero.

The smoothing optical system 20 uses a kaleidoscope optical system as shown in FIG. 3, for example.

In this kaleidoscope optical system, an entrance lens 21, a kaleidoscope 22 and an imaging lens 23 are arranged on the same optical axis.

In this kaleidoscope optical system, the shape of the intensity distribution of the laser beam can be arbitrarily set by changing the design of the kaleidoscope 22.

The shape of the laser beam output from this kaleidoscope optical system is shaped into a desired shape such as a circle as shown in FIG. 4 or an elliptical shape, a rectangular shape, a triangular shape or the like as shown in FIG.

The shape of the laser beam is shaped by changing the shape of the kaleidoscope 22 and disposing a slit plate having a desired shape on the output end side of the kaleidoscope optical system.

The smoothing optical system 20 is not limited to the kaleidoscope optical system and may have another structure.

FIG. 5 shows another configuration example of the smoothing optical system 20. A half mirror 25 and a mirror 26 as a branch optical system are arranged on one branch optical path of the half mirror 24.

On the other branch optical path of these half mirrors 24 and 25 and on the reflected optical path of the mirror 26, as shown in FIG.
As shown in (d), light-shielding plates 27 to 29 for setting laser beam passage areas and filters 30 to 32 for arbitrarily changing the intensity of the laser beam are arranged.

Half mirrors 33, 34 and a mirror 35 as a photosynthesis optical system are arranged on the optical path of the laser beam passing through these filters 30-32.

With such a smoothing optical system 20, when a laser beam is incident, this laser beam is split into two directions by the half mirror 24, and one of the laser beams reaches the half mirror 25 and Is further branched into two directions, and one of the laser beams reaches the mirror 26.

The laser beams branched to the other by the half mirrors 24 and 25 and the laser beam reflected by the mirror 26 respectively pass through the light shielding plates 27 to 29 to define the light passage areas. Filter 30 ~
By passing through 32, the intensity distribution changes.

The laser beams transmitted through these filters 30 to 32 are reflected by the half mirrors 33 and 34 and the mirror 3.
5 and smoothed with a desired intensity distribution.

There is also a method in which the intensity distribution of the laser beam has an arbitrary distribution. For example, when the laser path bends as shown in FIG. 7, the power required for curing differs between the inside and the outside. Therefore, if the intensity distribution shown in the right side of the figure is given, the curing becomes uniform.

In such a curved portion, since the moving distance of the inner laser beam and the moving distance of the outer laser beam are different, the intensity of the outer laser beam becomes high.

On the other hand, the deformation sensor 4 is attached to the detection head 40.
1, a stress sensor 42 and a fixed block 43 are provided.

A fixed block 43 is provided in the central portion of the detection head 40 as shown in the configuration view from above in FIG. 8, and the fixed block 43 is separated from the fixed block 43 by a distance of about 100 mm on both sides. A deformation sensor 41 and a stress sensor 42 are provided.

As shown in FIG. 9, the deformation sensor 41, the stress sensor 42, and the fixed block 43 are inclined at a predetermined angle with respect to the surface of the photocurable resin 2, and the deformation sensor 4
1 and the respective detection ends 44 and 45 of the stress sensor 42 and the fixed end 46 of the fixed block 43 are set to be slightly dipped from the surface of the photocurable resin 2.

The deformation sensor 41 and the stress sensor 4 are also included.
The shape and orientation of each of the detection ends 44, 45 and the fixed end 46 of the fixed block 43 are fixed on the scanning line of the laser beam.

Of these, the deformation sensor 41 is designed to have the rigidity as small as possible, and is stretched by the linear hardened material 47 formed by one scanning of the laser beam between the fixed end 46 and the detection end 44 of the fixed block 43. Almost no power,
It has a function to detect only the amount of deformation.

FIG. 10 is a specific structural diagram of the deformation sensor 41. FIG. 10A is a view seen from above and FIG. 10B is a side view.

The deformation sensor 41 is made of a metal material such as aluminum, and is a thin plate-shaped movable block 4 provided with a detection end 44 having a notch 44a.
8 and a fixed block 49 are two thin plates 5 parallel to each other.
It has a structure in which 0 and 51 are connected.

The thin plates 50 and 51 are designed to have a thickness of about 0.3 mm, a width of about 5 mm, and a length of about 75 mm, and have a rigidity of about 44 mN / mm.

Further, the fixed block 49 and the thin plates 50, 51
Strain gauges 52 and 53 are provided between and, and the amount of deformation is detected by these strain gauges 52 and 53.

The stress sensor 42 is designed so that the rigidity thereof is maximized, and the stress sensor 42 has a fixed end 46 and a detection end 4 of the fixed block 43.
Since the linear hardened material 47 formed by one scanning of the laser beam with respect to 5 hardly deforms, it has a function of detecting only the pulling force.

FIG. 11 is a concrete structural view of the stress sensor 42. FIG. 11 (a) is a view from above and FIG. 11 (b) is a side view.

The stress sensor 42 is made of, for example, a metal material such as aluminum, and is a thin plate-shaped movable block 5 provided with a detection end 45 having a notch 45a.
4 and the fixed block 55 are two thin plates 5 parallel to each other.
The structure is such that they are connected by 6, 57.

The thin plates 56, 57 are designed to have a thickness of about 0.3 mm, a width of about 5 mm, a length of about 10 mm, and a rigidity of about 18 N / mm.

Further, the fixed block 55 and the thin plates 56 and 57.
Strain gauges 58 and 59 are provided between and, and the amount of stress is detected by these strain gauges 58 and 59.

These deformation sensor 41 and stress sensor 42
The detection head 40 provided with is provided in the drive mechanism 60, and is driven by the drive mechanism 60 to move forward and backward and move up and down with respect to the resin container 1.

A cured material removing tool 61 is arranged above the deformation sensor 41 and the stress sensor 42, and the deformation sensor 41 is lowered by descending the cured material removing tool 61.
Also, the linear cured material 47 attached to the stress sensor 42 is removed.

A computer 66 is connected to the deformation sensor 41 and the stress sensor 42 via strain amplifiers 62 and 63 and A / D converters 64 and 65, respectively. Accordingly, the deformation amount detected by the deformation sensor 41 and the stress detected by the stress sensor 42 are sent to the computer 66 as deformation information D and stress information F, respectively.

The computer 66 stores the deformation information D and the stress information F in an internal memory, and evaluates and determines the linear condition cured material 47.
7 and each function of the modeling control means 68 for setting the molding conditions.

That is, a storage device 69 is connected to the computer 66, and in this storage device 69, a shape database 70, a deformation database 71 and a molding condition / deformation
A stress database 72 is formed.

Among them, the shape database 70 stores a plurality of shapes to be formed. The shape to be shaped is
For example, as shown in FIGS. 12 (a) to 12 (c), there are a box, a cantilever, a U-shape, and the like. These shapes are deformations peculiar to the shape when the photocurable resin 2 is irradiated with a laser beam and cured. Occurs.

In the deformation database 71, the relational expression or data between the deformation and the stress obtained based on the basic modeling experiment and experience, and the accuracy of the modeled object, that is, as shown in FIG. The relationship between the deformation information D detected for the line-shaped cured product and the surface-cured product that are modeled when the light is irradiated, the warpage deformation amount Ds with respect to the stress information F, and the contraction deformation amount Dc is stored for each modeling shape. ing.

For example, the warp deformation Ds of the cantilever which is one of the modeling shapes shown in FIG. 12 (b) is Ds = f (F, L) = K ₂ · L · F ^1/2 (1) It is represented by a formula. Where F is stress, L
(L ₁ , L ₂ , L ₃ , ...) Is the length of the cantilever.

The shrinkage deformation Dc of the cube having the same shape is expressed by the relational expression of Dc = f (D) = K ₁ .Dl (2). Here, D is a transformation.

The modeling conditions / deformation / stress database 72 stores modeling conditions found based on basic modeling experiments and experience, that is, relational expressions of laser beam intensity and its scanning speed with deformation and stress. For example, the laser intensity with respect to the laser scanning speed of the linear cured product, the deformation of the planar cured product with respect to the scanning interval, and the like are stored.

Therefore, the modeling condition judging means 67 inputs the deformation information D detected by the deformation sensor 41 or the stress information F detected by the stress sensor 42, and the deformation database is formed from these deformation information D and stress information F. The warp deformation amount D is calculated by using the above relational expressions (1) and (2) stored in 71.
s, the shrinkage deformation amount Dc, and the warp deformation amount Ds and the shrinkage deformation amount Dc have a function of evaluating and determining whether or not the shape error of the cured portion of the photocurable resin 2 is within the allowable value. .

The modeling control means 68 is a modeling condition determination means 6
If the shape error of the cured portion of the photocurable resin 2 is within the allowable value according to 7, modeling is performed, and if the shape error of the cured portion of the photocurable resin 2 exceeds the allowable value, molding conditions, deformation, stress It has a function of changing the modeling conditions such as the laser beam intensity stored in the database 72 and performing the modeling.

The modeling control means 68 has a function of setting the modeling conditions of the changed laser beam intensity and its scanning speed for the laser oscillator 5 and the galvanometer mirror 10.

Next, the operation of the apparatus configured as described above will be described with reference to the flow chart of modeling shown in FIG.

Before irradiating the photocurable resin 2 with a laser beam to perform optical modeling, the amount of deformation and the amount of stress that directly determine the precision of the modeled object are detected.

That is, by the movement of the detection head 40, the deformation sensor 41, the stress sensor 42, and the detection ends 44a and 45a of the fixed block 43 and the fixed end 46 are immersed in the photocurable resin 2 as shown in FIG. And these detection ends 44
The shape and posture are adjusted so that the upper end line connecting the a and 45a and the fixed end 46 becomes equal to the liquid surface of the photocurable resin 2.

The deformation sensor 41 and the stress sensor 4 are also included.
Each of the detection ends 44a and 45a of the fixed block 43 and the fixed end 46 of the fixed block 43 is arranged on the scanning line of the laser beam.

The positions where the deformation sensor 41, the stress sensor 42, and the fixed block 43 are arranged are different from the positions where the optical molding is actually performed.

When a laser beam of intensity W is output from the laser oscillator 5, the laser beam is scanned by the galvanometer mirror 10 to detect the deformation sensor 41, the stress sensor 42, and the fixed ends of the fixed block 43. The photo-curable resin 2 is scanned once at a scanning speed V so as to intersect with 46.

A linear shaped cured product 47 having a length of 100 mm, for example, is formed by one scan of this laser beam.

As the linear cured product 47 is cured and shrunk, the tensile force generated in the linear cured product 47 is
Each of the detection ends 44a of the deformation sensor 41 and the stress sensor 42,
It acts on 45a.

Of these, the deformation sensor 41 has the rigidity made as small as possible, and therefore, the linear hardened material 47 formed between the fixed end 46 and the detection end 44 of the fixed block 43 has almost no tensile force. Only the amount of deformation is detected.

That is, when a force acts on the detection end 44a and the movable block 48 is displaced in the detection direction, each thin plate 50,
Deformation occurs at 51. At this time, the surface strain generated in each thin plate 50, 51 is detected by each strain gauge 52, 53.

Further, since the stress sensor 42 is made as rigid as possible, the linear hardened material 47 formed between the fixed end 46 and the detection end 45 of the fixed block 43 is hardly deformed and is pulled. Detect only force.

That is, when a force acts on the detection end 45a and the movable block 54 is displaced in the detection direction, each thin plate 56,
Deformation occurs at 57. At this time, the surface strain generated in each thin plate 56, 57 is detected by each strain gauge 58, 59.

The deformation amount detected by the deformation sensor 41 and the stress amount detected by the stress sensor 42 are the strain amplifiers 62 and 63 and the A / D converter 6, respectively.
Deformation information D and stress information F are sent to the computer 66 via the Nos. 4 and 65.

The computer 66, in step # 1, prints a shaping database 70 for carrying out stereolithography.
Then, the deformation information D detected by the deformation sensor 41 and the stress information F detected by the stress sensor 42 are input.

In step # 2, # 3 to step # 4, the shaping condition determining means 67 of the computer 66 determines, for example, the warp deformation Ds of the cantilever and the contraction deformation Dc of the cube, which are one of the shaping shapes, from the deformation database 71. The relational expressions (1) and (2) to be obtained are searched, and the deformation information D and the stress information F are substituted into these relational expressions (1) and (2) to obtain the warp deformation Ds of the cantilever and the contraction deformation Dc of the cube.

Next, the modeling condition judging means 67 determines in step #
In 5, it is evaluated whether or not the warp deformation amount Ds and the contraction deformation amount Dc are within the allowable values of the shape error of the cured portion of the photocurable resin 2.

If the shaping condition determination means 67 determines that the shape error of the linear-shaped cured product 47 is within the allowable value, the shaping control means 68 determines in step # 6 that the shaping conditions of the laser beam intensity and its scanning speed are appropriate. It is judged that there is such a judgment, and the laser oscillator 5 and the galvanometer mirror 10 are instructed to perform modeling.

However, if the shape error of the line-shaped cured product 47 exceeds the allowable value, the molding control means 68 moves to steps # 7 to # 9 and is stored in the molding condition / deformation / stress database 72. Change the molding conditions such as laser beam intensity.

Then, the shaping control means 68 sets the shaping conditions of the changed laser beam intensity and its scanning speed for the laser oscillator 5 and the galvanometer mirror 10.

When the shaping conditions of the laser beam intensity and the scanning speed thereof are set in this way, the actual shaping is carried out.

First, the molding base 4 is placed near the surface of the photocurable resin 2 by controlling the elevator 3 to move up and down.

When a laser beam is output from the laser oscillator 5, the laser beam passes through a smoothing optical system 20 using a kaleidoscope 22 as shown in FIG. Smoothed.

The smoothing optical system 20 using the kaleidoscope 22 collects the laser beam on the kaleidoscope 22 by the incident lens 21 when the laser beam enters as shown in FIG. This kaleidoscope 22
In, the incident laser beam is repeatedly reflected in the kaleidoscope, and as a result, the intensity distribution of the output laser beam is smoothed. Then, the laser beam output from the kaleidoscope 22 is sent to the galvanometer mirror 10 through the imaging lens 23.

In the smoothing optical system 20, the shape of the intensity distribution of the laser beam can be arbitrarily set by changing the design of the kaleidoscope 22, for example.

By arranging a slit plate having a desired shape on the output end side of the kaleidoscope optical system, the shape of the laser beam is a circle as shown in FIG. It is shaped into a desired shape such as a rectangle or a triangle.

The smoothing optical system 20 is not limited to the kaleidoscope optical system, and as shown in FIG.
Alternatively, the optical fiber 36 may be curved, as shown in FIG.

For example, in the smoothing optical system 20 using the half mirror 24 and the like shown in FIG. 5, when the laser beam is incident on the half mirror 24, this laser beam is split into two directions, and one of the laser beams is split. The beam is incident on the half mirror 25, where it is further branched into two directions, and one of the laser beams is sent to the mirror 26.

The laser beam branched to the other side by the half mirror 24 passes through the light shielding plate 27 and the filter 30 and reaches the half mirror 33.

At the same time, the other laser beam branched by the half mirror 25 passes through the light blocking plate 28 and the filter 31 to reach the half mirror 34, and the laser beam reflected by the mirror 26 passes through the light blocking plate 29 and the filter 32. It passes through and reaches the mirror 35.

Then, the half mirror 34 and the mirror 26
The laser beams reflected by the
Where each of the previously branched laser beams is combined.

The laser beam thus synthesized passes through the light shielding plates 27 to 29 and the filters 30 to 32, and is thus smoothed with a desired intensity distribution.

If the optical fiber 36 is curved as shown in FIG. 7, the moving distance of the laser beam inside the curved portion is different from the moving distance of the outer laser beam.
The intensity of the outer laser beam is increased. This makes it possible to obtain a laser beam smoothed with a desired intensity distribution.

The laser beam whose intensity distribution has been smoothed by the smoothing optical system 20 in this way is transmitted by the galvanometer mirror 10.
Thus, the surface of the photocurable resin 2 is scanned, and the cured portion of the first layer is formed.

Subsequently, the molding base 4 is lowered by the elevation control of the elevator 3, and the laser beam output from the laser oscillator 5 is moved by the galvano mirror 10 to the photocurable resin 2.
The surface of is scanned and the cured portion of the second layer is formed.

Thereafter, similarly, the modeling base 4 descends and the operation of scanning the surface of the photocurable resin 2 with the laser beam is repeated, and a desired three-dimensional shape is modeled.

As described above, in the first embodiment, the laser beam having the intensity distribution of the Gaussian distribution output from the laser oscillator 5 is transmitted through the smoothing optical system 20 using the kaleidoscope 22 or the like. Since the light-curable resin 2 is smoothed by the above and scanned, the intensity distribution of the laser beam can be smoothed, and high-precision modeling can be performed.

That is, the degree of curing in the XY plane in the cured product of the photocurable resin 2 can be made uniform, and the overlap of the laser beam scans during modeling can be minimized.

Further, since the laser beam can be formed into a rectangular shape such as a rectangle or a triangle as shown in FIG. 4, the energy given to the photocurable resin 2 per unit area can be made uniform.

In this way, the degree of curing is made uniform, and the overlap of the laser beam scans during modeling can be minimized.
In addition, since the energy applied to the photocurable resin 2 can be made uniform, the accuracy of the three-dimensional structure can be increased.

On the other hand, the photocurable resin 2 is irradiated with a laser beam to detect the amount of deformation or shrinkage stress in the linear-shaped cured product 47, and the linear-shaped cured product 47 is calculated from the amount of deformation or shrinkage stress based on modeling data. If the shape error of the linear shape cured product 47 is within the allowable value, the molding is carried out.
Moreover, when the shape error of the linear-shaped cured product 47 exceeds the allowable value, the molding conditions are changed to perform the molding. From these deformations and shrinkage stresses, highly accurate modeling can be performed under optimal modeling conditions.

That is, the laser beam photocurable resin 2
Photocurable resin 2 due to fluctuations in laser beam intensity, changes in laser beam intensity distribution, temperature changes, etc.
Even if there is a change in the characteristics, the optimum molding conditions can be guaranteed and high-precision three-dimensional molding can be performed.

Further, the curing / shrinking phenomenon of the photocurable resin 2 can be measured in real time, the curing / shrinking phenomenon of the photocurable resin 2 can be clarified, and the stress and deformation occurring in the cured product can be calculated.

Therefore, it is possible to measure the deformation and shrinkage stress that occur when the photocurable resin 2 is hardened in real time by using the laser beam having the smoothed intensity distribution, and the optimum molding conditions can be obtained from these deformation and shrinkage stress. Highly accurate modeling is possible.

Here, the measurement result of the contraction force generated when the both ends of the linear cured product 47 formed when the laser beam is linearly scanned once will be described.

In this measurement, a stress sensor 42 having an output of 1.88 μst / mm and a rigidity of 18.5 mN / mm is used.

In this measuring method, the shrinkage force generated in the linear shaped cured product 47 having a length of 100 mm is measured by the stress sensor 42, and the modeling conditions are that the curing depth is 0.4 mm and 0.5.
mm, 0.6 mm, 0.7 mm, laser intensity 110 m
W, 235 mW, 465 mW.

FIG. 14 is a diagram showing the relationship between the hardening depth and the shrinking force after the hardening is completed.

No change in shrinkage force due to the difference in laser intensity is observed up to the hardening depth of 0.6 mm. Curing depth 0.
At 7 mm, the contraction force is large when the laser intensity is 465 mW. This is considered to be a change in the cross-sectional area of the linear cured product 47.

Therefore, it is understood that the shrinkage force of the linear cured product 47 monotonically increases with the curing depth.

The present invention is not limited to the above-mentioned one embodiment, but may be modified as follows.

For example, in smoothing the laser beam intensity distribution, not only the laser oscillator 5 but also a UV lamp may be used as the light source.

It is also applicable to a collective exposure apparatus.

On the other hand, for the judgment evaluation of shrinkage of the photocurable resin 2, for example, in the above-mentioned one embodiment, the linear-shaped cured product 4 is used.
Although the deformation and stress generated in 7 are detected, the present invention is not limited to this, and the deformation and stress generated in the cured surface shape are detected to evaluate whether the shape error of the cured surface shape is within the allowable value. You may.

In this case, conditions such as a laser beam scanning pattern and a scanning interval are added to the modeling conditions.

When the deformation sensor 41 and the stress sensor 42 are used, the deformation and stress on one side of the surface-shaped cured material are detected one-dimensionally. If a biaxial stress sensor provided with, for example, two sets of parallel thin plates that are orthogonal to each other is prepared, it is possible to detect a two-dimensional stress. The same method can be applied to the deformation sensor.

Here, the measurement result of the shrinkage deformation of the surface-shaped cured product formed when the laser beam is scanned will be described.

In this measurement, as shown in FIG. 15, two deformation sensors 41a and 41b are arranged at intervals of 100 mm, for example, and the shrinkage deformation of the square surface-shaped cured product 80 is measured.

These deformation sensors 41a and 41b have outputs of 155 μst / mm and 151 μst / mm, respectively, and rigidity 2
A material having a performance of 8.8 mN / mm and 33.5 mN / mm is used.

Then, the two deformation sensors 41a and 4a are arranged such that both ends of one side of the surface-shaped cured product 80 are separated by 100 mm.
1b from the start of laser scanning, for example, 1
The outputs of the deformation sensors 41a and 41b for 60 seconds are recorded.

The scanning patterns of the laser beam are as follows: single scan shown in FIGS. 16 (a) and 16 (b) (scanning the laser beam in one direction) and cross scan shown in FIGS. 16 (c) and 16 (d). There are four patterns (scanning in two directions orthogonal to each other), and shrinkage in two directions is evaluated for these scanning patterns.

The molding conditions are such that the deformation sensors 41a and 41b have a performance of 0.2 in the case of single scan.
5 mm, hatch spacing 0.127 mm, 0.152 mm,
It is 0.178 mm and 0.203 mm.

In the case of cross scan, the curing depth is 0.
25mm, hatch spacing 0.203mm, 0.228m
m, 0.254mm, 0.279mm, 0.305m
m, 0.330 mm.

In such a measurement, the deformation amount in the laser scanning direction (first time in the case of cross scanning) is Dx, and the deformation amount in the direction orthogonal thereto is Dy.

FIG. 17 to FIG. 19 are examples of measurement results,
Figure 17 shows a single scan with a hatch spacing of 0.203m
m, FIG. 18 and FIG. 19 are cross scans and hatch intervals are 0.203 mm and 0.279 mm.

It is confirmed that most of the deformation in the cross scan is caused by the second scan as shown in FIGS. 17 and 18.

FIG. 20 is a diagram showing the relationship between the hatch interval and the final deformation.

In the case of single scan, the deformation amount Dy is D
less than x. The reason for this is presumed that the shrinkage generated during the scanning of the laser beam does not affect the deformation of the already hardened portion and the deformation of the entire planar hardened material which is alleviated by the inflow of the uncured resin.

In the case of cross scan, the hatch interval is 0.
When it is 25 mm or more, the deformation amount Dy becomes smaller than Dx. This is because the line-shaped cured product has a width of 0.25 mm or less, and thus the adjacent line-shaped cured products are separated in the first scan at this hatch interval.

FIG. 21 is a graph showing the relationship between the laser irradiation energy density and the deformation after completion of curing. The shrinkage deformation of the surface-shaped cured product tends to be proportional to the laser irradiation density. It can be seen that the deformation of the surface-shaped cured product 80 is almost proportional to the laser irradiation density.

The shrinkage evaluation of the photocurable resin 2 may be modified as follows.

Instead of the deformation sensor 41, a Teflon marker is floated at a detection point on the liquid surface of the photocurable resin 2 so as not to adversely affect the photocurable resin 2, and its behavior is C
Deformation of the cured product due to curing / shrinkage may be detected by capturing an image with a DD camera or the like.

Further, in the above-described one embodiment, the deformation and stress of the photocurable resin 2 are detected for each layer of the cured product, but empirically the laser intensity and the temperature of the photocurable resin 2 are short. If it is clear that it does not change with time, it is not always necessary to detect the deformation of the photocurable resin 2 for each layer.

For example, a procedure in which the deformation and stress of the photocurable resin 2 are detected once immediately after the start of modeling and thereafter the detection for confirmation is performed hourly is sufficient.

Further, in the above-mentioned one embodiment, the deformation sensor 41 and the stress sensor 42 which are ideally designed independently detect the deformation and stress of the linear hardened material 47. It is not easy to realize an ideal deformation sensor 41, that is, a deformation sensor having almost zero rigidity due to design restrictions.

Even in such a case, the deformation can be detected with sufficient accuracy by compensating the deformation by the following procedure.

For example, the net deformation amount increment ΔX in a certain minute time is calculated from the equation ΔX = (Kp (t) + Ks) / Kp (t) × ΔXe (3).

Here, Kp (t) acts on the deformation sensor 41 calculated from the stress amount detected by the stress sensor 42, the deformation amount detected by the deformation sensor 41, and the deformation amount and the rigidity of the deformation sensor 41. Calculated from the stress.
Further, Ks is the rigidity of the deformation sensor 41, and ΔXe is the increment of the output of the deformation sensor 41.

By adding this net deformation amount increment ΔX from the curing start point to time t, the net deformation amount Δ at time t is obtained.
X (t) is required.

Further, as shown in FIG. 22, the galvano mirror 1
The collimator lens 81 may be arranged on the optical path of the laser beam scanned by 0 to adjust the optical path of the scanned laser beam.

[0175]

As described in detail above, claim 1 of the present invention,
According to 5, 6, and 7, it is possible to provide an optical modeling apparatus capable of smoothing the intensity distribution of the laser beam and performing highly accurate modeling.

According to claims 2, 8 and 9 of the present invention,
It is possible to provide a stereolithography apparatus capable of measuring the deformation and shrinkage stress generated when the photocurable resin is cured in real time.

According to claims 3, 8 and 9 of the present invention,
It is possible to provide a stereolithography apparatus capable of measuring deformation and shrinkage stress generated when the photocurable resin is cured in real time and performing high-precision molding under the optimum molding conditions from the deformation and shrinkage stress.

According to claims 4, 8, 9, and 10 of the present invention, the deformation and shrinkage stress generated when the photocurable resin is cured are used in real time by using a laser beam having a smoothed intensity distribution. It is possible to provide an optical modeling apparatus that can perform high-precision modeling under optimal modeling conditions based on the deformation and shrinkage stress measured by the above.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of an optical modeling apparatus according to the present invention.

FIG. 2 is a functional block diagram of the device.

FIG. 3 is a configuration diagram of a smoothing optical system formed by a kaleidoscope.

FIG. 4 is a diagram showing a shape of a laser beam.

FIG. 5 is a configuration diagram of a smoothing optical system formed of a half mirror or the like.

FIG. 6 is a diagram showing an intensity distribution of a laser beam.

FIG. 7 is a configuration diagram of a smoothing optical system using a curved portion of an optical fiber.

FIG. 8 is a configuration diagram of the stereolithography apparatus viewed from above.

FIG. 9 is a layout view of a deformation and stress sensor.

FIG. 10 is a configuration diagram of a deformation sensor.

FIG. 11 is a configuration diagram of a stress sensor.

FIG. 12 is a diagram showing a modification of a modeled object.

FIG. 13 is a flow chart of modeling.

FIG. 14 is a diagram showing a result of real-time measurement of shrinkage stress of a linear cured product.

FIG. 15 is an arrangement view of two deformation sensors used for measuring shrinkage deformation of a surface-shaped cured product.

FIG. 16 is a diagram showing a scanning pattern.

FIG. 17 is a diagram showing an example of a result of measurement of shrinkage deformation of a surface-shaped cured product in a single scan.

FIG. 18 is a diagram showing an example of a result of measurement of shrinkage deformation of a surface-shaped cured product by a cross scan.

FIG. 19 is a diagram showing an example of a result of measurement of shrinkage deformation of a surface-shaped cured product by cross scan.

FIG. 20 is a diagram showing a relationship between a hatch interval and deformation of a surface-shaped cured product.

FIG. 21 is a diagram showing a relationship between laser irradiation density and deformation of a surface-shaped cured product.

FIG. 22 is a configuration diagram of an optical modeling apparatus using an optical system for adjusting an optical path.

FIG. 23 is a configuration diagram of a stereolithography device using a conventional orthogonal plotter.

FIG. 24 is a configuration diagram of a stereolithography apparatus using a conventional galvano mirror.

FIG. 25 is a diagram showing an intensity distribution of a laser beam.

FIG. 26 is a diagram showing scanning with a laser beam in modeling.

[Explanation of symbols]

1 ... Resin container, 2 ... Photocurable resin, 3 ... Elevator, 4
… Modeling base, 5… Laser oscillator, 10… Galvano mirror, 20… Smoothing optical system, 22… Kaleidoscope, 2
4, 25 ... Half mirror, 27-29 ... Shading plate, 30-
32 ... Filter, 40 ... Detection head, 41 ... Deformation sensor, 42 ... Stress sensor, 43 ... Fixed block, 47 ... Linear shaped cured product, 60 ... Drive mechanism, 66 ... Computer, 6
7 ... Modeling condition determination means, 68 ... Modeling control means, 69 ... Storage device, 70 ... Shape database, 71 ... Deformation database, 72 ... Modeling condition / deformation / stress database.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Ito 33, Shinisogo-cho, Isogo-ku, Yokohama, Kanagawa Prefecture

Claims (10)

[Claims] 1. A stereolithography apparatus for scanning light on a photocurable resin to cure the photocurable resin, and stacking the cured portions to form a three-dimensional shape, wherein the photocurable resin is scanned. An optical modeling apparatus, comprising: a smoothing optical system that smoothes the intensity of light to be generated. 2. A stereolithography apparatus for scanning a photocurable resin with light to cure the photocurable resin and stacking the cured portions to form a three-dimensional shape, wherein the photocurable resin is cured. The sensor for detecting at least one of the deformation amount and the contraction stress in the formed portion, and the photocurability based on the modeling data including at least the modeling accuracy preset from at least one of the deformation amount and the contraction stress detected by the sensor. An optical modeling apparatus, comprising: a modeling condition determining unit that evaluates whether or not a shape error of a cured portion of the resin is within an allowable value. 3. An optical modeling apparatus that scans a photocurable resin with light to cure the photocurable resin, and laminates the cured parts to form a three-dimensional shape, wherein the photocurable resin is cured. The sensor for detecting at least one of the deformation amount and the contraction stress in the formed portion, and the photocurability based on the modeling data including at least the modeling accuracy preset from at least one of the deformation amount and the contraction stress detected by the sensor. If the shape error of the cured portion of the photocurable resin is within the allowable value, the molding condition determination means for evaluating whether or not the shape error of the cured portion of the resin is within the allowable value. Modeling control means for carrying out modeling and changing the modeling condition consisting of at least the intensity of light to carry out modeling when the shape error of the cured portion of the photocurable resin exceeds an allowable value. An optical modeling apparatus, comprising: 4. An optical modeling apparatus that scans a photo-curable resin with light to cure the photo-curable resin and laminates the cured parts to form a three-dimensional shape. The photo-curable resin is scanned. A smoothing optical system that smoothes the intensity of light, a sensor that detects at least one of the deformation amount and the contraction stress in the cured portion of the photocurable resin, and the deformation amount or the contraction stress that is detected by the sensor. Modeling condition determining means for evaluating whether or not a shape error of a cured portion of the photocurable resin is within an allowable value based on modeling data including at least modeling accuracy preset from at least one of the modeling conditions; If the shape error of the cured portion of the photocurable resin is within the allowable value by the determination means, then modeling is performed, and at least if the shape error of the cured portion of the photocurable resin exceeds the allowable value. Optical shaping apparatus for a molding control means for performing shaping by changing the molding condition consisting of the intensity of the serial light, characterized by comprising a. 5. The stereolithography apparatus according to claim 1, wherein the smoothing optical system is formed by a kaleidoscope that smoothes light having a Gaussian distribution intensity distribution. 6. The smoothing optical system includes a kaleidoscope that smoothes light having an intensity distribution of a Gaussian distribution, and a slit plate having a desired shape arranged on the output end side of the kaleidoscope. The stereolithography apparatus according to claim 1 or 4, characterized in that 7. The smoothing optical system is disposed on each optical path of each light branched by the branching optical system and a branching optical system for branching the light scanning the photocurable resin into a plurality of beams. A light-shielding plate that sets a light passage area, a filter that is arranged on each optical path of each light branched by the branching optical system, and that arbitrarily sets the intensity of these lights, and a light-shielding plate and each filter that has passed through the filter. The photolithography apparatus according to claim 1 or 4, further comprising: a photosynthesis optical system that combines light to obtain light whose intensity distribution is smoothed. 8. The sensor includes a deformation sensor that detects a deformation amount of a cured portion of the photocurable resin, and a stress sensor that detects a tensile force at a cured portion of the photocurable resin. The optical modeling apparatus according to claim 2, wherein each of the detection ends of the sensor and the stress sensor is arranged on the scanning line of the light. 9. The modeling condition determination means retains modeling data having a function or knowledge representing a relationship between a deformation amount and a stress and a modeled object accuracy obtained based on at least a basic modeling experiment or experience, and the sensor is provided. It is evaluated whether or not the shape error of the cured portion of the photocurable resin is within an allowable value based on the modeling data from at least one of the deformation amount and the contraction stress detected by The stereolithography apparatus according to 2, 3, or 4. 10. A stereolithography apparatus for scanning a photocurable resin with light to cure the photocurable resin and stacking the cured portions to form a three-dimensional shape, wherein the photocurable resin is cured. A sensor for detecting at least one of the deformation amount or the contraction stress in the portion, and at least the surface-cured product from the deformation amount or the contraction stress detected by the sensor when the photocurable resin is planarly scanned with the light. A deformation amount calculation unit that obtains a deformation amount, and a shape error of a cured portion of the photocurable resin is an allowable value based on modeling data including at least modeling precision preset from the deformation amount calculated by the deformation amount calculation unit. If the shape error of the cured portion of the photocurable resin is within the allowable value by the molding condition judging means for judging whether or not it is inside And a shaping control means for performing shaping by changing a shaping condition including at least the intensity of the light when the shape error of the cured portion of the photocurable resin exceeds an allowable value. Modeling equipment.