JPH11221861A - Formation of three-dimensional shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a three-dimensional shape by which thickness of a photocuring layer can be accurately set. SOLUTION: A liquid storage tank 10 is equipped with a liquid level control means which consists of a drainage port 18 for discharging photocuring resin liquid 20 exceeding a standard liquid level Lo a valve plate 70 and its driving mechanism 72 or the like. In a process for sinking a forming base 30, the forming base 30 is once sunk deeper (to ΔX) than the depth position (t) corresponding to thickness of the aimed photocuring layer 50. Thereafter, the forming base 30 is returned to depth position (t) corresponding to thickness of the aimed photocuring layer 50 and also discharge of resin liquid 20 due to the liquid level control means is stopped in the interval of this process. After the above- mentioned process is finished, discharge of resin liquid 20 is performed by the liquid level control means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a three-dimensional shape, and more particularly to a method of manufacturing a three-dimensional three-dimensional article by using a photocurable resin which is cured by light irradiation. Things.

[0002]

2. Description of the Related Art A method of forming a three-dimensional shape by using a photo-curable resin is a conventional mechanical processing method or the like by precisely controlling light irradiation using a laser beam irradiation device or a computer. Research and development have been promoted as a method capable of easily forming a fine and accurate three-dimensional shape that cannot be realized by the method described in Japanese Patent Application Laid-Open No. Sho 62-35.
A method disclosed in Japanese Patent Application Laid-Open No. 966, and Japanese Patent Application Laid-Open No. 61-114817 is known.

FIG. 4 shows an example of a conventional method for forming a three-dimensional shape. In a storage tank 1 in which a photo-curable resin liquid 2 is stored, a molding table 3 which can be moved up and down directly below the liquid level is placed. By submerging and irradiating a laser beam 4 radiated from a laser irradiating device to the liquid surface, the resin liquid 2 having a certain thickness existing between the liquid surface and the molding table 3 is light-cured to form a light-cured layer 5. Let it form. By scanning the laser beam 4 in the plane direction, the shape pattern of the photocurable layer 5 can be freely drawn. When one photo-cured layer 5 is formed, the molding table 3 is further sunk, and the photo-cured layer 5 is covered with a new resin liquid 2 having a constant thickness, and then irradiated with the laser beam 4 in the same manner as described above. I do. In this method, the laser beam 4 is irradiated always in the same liquid surface position or the reference liquid level L _0. The thickness t of the photocurable layer 5 formed at a certain stage is determined by the descending distance ΔX of the molding table 3 lowered at the immediately preceding stage. By repeating such a process, a plurality of photocurable layers 5 are stacked on the molding table 3 to form a desired three-dimensional shape. In order to improve the dimensional accuracy and shape accuracy of the three-dimensional shape manufactured by this method, it is necessary to form the thickness t of the photocurable layer 5 at each stage as thinly and accurately as possible.

In the method described above, the storage tank 1
The resin table 2 having a certain thickness is supplied on the photo-cured layer 5 formed earlier by gradually sinking the molding table 3 in the inside, but while the molding table 3 is fixed, There is also a method of supplying the resin liquid 2 having a certain thickness on the photocurable layer 5 by additionally supplying a new resin liquid 2 to the liquid storage tank 1. In this case, the reference liquid level L to be irradiated with the laser beam 4
_{Since 0} gradually increases, the focal position of the laser beam 4 also needs to be changed stepwise. However, in place of changing the focal position of the laser beam 4, stepwise lower the overall fluid storage bath 1, a method to make the reference liquid level L ₀ unchanged.

[0005] In the method of forming such a three-dimensional shape, wherein the reference liquid level L ₀ fluctuates, the error and variation in the thickness of the photocurable layer to form a dark each stage, photocuring of multiple layers There is a problem that the three-dimensional shape formed by stacking layers has a direct effect on the shape accuracy and dimensional accuracy. In order to keep the liquid level of the photocurable resin liquid constant, Japanese Patent Application Laid-Open
No. 27 proposes a method as disclosed.
In this method, as shown in FIG. 5, a drain port 1a for regulating the liquid level is provided on the wall surface of the liquid storage tank 1, and the resin liquid is extended to a height exceeding the drain port 1a. be supplied to 2, excess resin liquid 2 so flows out from the liquid discharge port 1a, the liquid level L ₀ of the resin solution 2 in reservoir 1 is always that is kept constant.

[0006]

However, even with the above method, the liquid level may not be kept constant. This is because in the conventional method of forming a three-dimensional shape, the molding table 3
During the movement, the molding table 3 is once immersed in the resin liquid 2 deeper than the predetermined descent distance ΔX, and then the molding table 3 is raised and returned to the predetermined descent distance ΔX. is there. The operation of the molding table 3 as described above is performed by the molding table 3
Is temporarily immersed deeply in the resin solution 2 to form the photocurable layer 5.
This is because the resin liquid 2 can easily flow into the upper part of the substrate and the resin liquid 2 having a sufficient thickness can be quickly supplied onto the photocurable layer 5.

Therefore, as shown in FIG.
Is lowered to a depth slightly larger than the distance ΔX corresponding to the thickness t of the photocurable layer 5, that is, by a distance ΔX + α, the arm 3a of the molding table 3 is inserted into the resin liquid 2 and pushes the resin liquid 2. only exception, since the liquid level L is increased, the resin liquid 2 present between the elevated liquid level L and the original liquid level L ₀ is flows out from all liquid discharge port 1a.

Thereafter, as shown in FIG. 7, when the molding table 3 is raised and positioned at a distance of ΔX from the reference liquid level L _0, that is, the lower end of the drain port 1 a, the arm portion 3 a of the molding table 3 Is partially withdrawn from the resin liquid 2, and the sixth
The arm portion 3 inserted in the resin liquid 2 is different from the state shown in the figure.
The volume of a, that is, the amount of the resin liquid 2 that has been pushed away by the arm portion 3a is reduced. Then, only became small amount of resin liquid 2 which is aside pushed by the arm portions 3a, lower the liquid surface of the resin liquid 2, the actual than the reference liquid level L ₀ of Kanto to the position of the drain port 1a The liquid level L drops.

The difference ΔL between the liquid level L and the reference liquid level L ₀ is
The cross-sectional area S ₁ of the eighth arm portion 3a of the forming table 3 shown in FIG., From the cross-sectional area S ₁ excluding liquid resin 2 of liquid surface area S ₂ Prefecture of is calculated by the following equation. ΔL = α · (S ₁ / S ₁ ) (1) If S ₁ is negligibly small compared to S ₂ , the value of ΔL can be neglected, but in fact, ΔL is quite large and light This greatly affects the thickness of the hardened layer 5 and the dimensional accuracy of the three-dimensional shape. In particular, when a high-precision three-dimensional shape is to be manufactured, a serious error occurs.

As described above, in the conventional method for forming a three-dimensional shape, it is difficult to accurately set the thickness of the resin liquid to be cured by irradiating light, that is, the thickness of the photocurable layer. Since an error or variation occurs in the thickness, there is a problem that the dimensional accuracy and the shape accuracy of the three-dimensional shape to be manufactured are deteriorated. Accordingly, an object of the present invention is to provide a method for forming a three-dimensional shape capable of accurately setting the thickness of a photocurable layer by solving the above-mentioned problems of the conventional technology.

[0011]

According to the present invention, there is provided a method for forming a three-dimensional shape, which comprises:
In a method of irradiating light to the liquid surface at each step to form a photocurable layer having a predetermined shape, and forming a desired three-dimensional shape by stacking a plurality of photocurable layers on a molding table. In the process of sinking the molding table, a liquid level regulating means for discharging the photocurable resin liquid exceeding the reference liquid level is used, and the molding table is temporarily moved from the depth position corresponding to the thickness of the intended photocurable layer. After being immersed deeply, return to the depth position corresponding to the thickness of the target photo-cured layer, and during the above-mentioned step, the discharge of the resin liquid by the liquid level regulating means is stopped, and after the above-mentioned step, the liquid The resin liquid is discharged by the surface regulating means.

The method of irradiating the photocurable resin liquid with light and the method of supplying the photocurable resin liquid on the photocurable layer can be the same as the method of forming a normal three-dimensional shape. In order to supply the photocurable resin liquid onto the photocurable layer, a method in which the molding table is submerged in a liquid storage tank stepwise is adopted. The method of using a laser beam as the light for forming the photocurable layer is a method that can quickly form a photocurable layer having a fine shape, but can also be used to irradiate a beam of ordinary light energy. . The beam light is applied through an optical system such as a lens, a mirror, and a prism so as to focus on the liquid surface of the photocurable resin liquid or near the liquid surface. The position where this light beam concentrates most is called the condensing position. At this time, the beam spot diameter of the irradiation light on the liquid surface becomes smallest when the focus is on the liquid surface, that is, when the light condensing position is set on the liquid surface. The smaller the beam spot diameter, the higher the density of the irradiated light energy, and the more the photocurable resin liquid is cured. In addition, the smaller the beam spot diameter, the smaller the area of the photocurable resin liquid that cures at the same time, and a finer pattern can be formed. In consideration of the above, the focal point of the irradiation light, that is, the condensing position is set so that the beam spot diameter on the liquid surface is in an appropriate state. In order to specifically change the beam spot diameter, a method of changing the position of a lens or a mirror in the above-described optical system can be easily and accurately performed. Means can be adopted. As a means for changing the position of the lens or the mirror, the same mechanism or device as that employed in an optical system in a normal laser irradiation device or the like is used.

As the liquid level regulating means, various liquid level regulating means employed for maintaining a constant liquid level in an ordinary liquid handling apparatus can be used. For example, on the wall surface of the storage tank, if a drain port or a drain weir that can be freely opened is provided at a position corresponding to the reference liquid level, while these drain ports and the like are open, All resin liquid exceeding the reference liquid level is discharged,
When the drain port or the like is closed, it becomes possible to store the resin liquid to a liquid level higher than the reference level.

Then, after one photo-cured layer is formed,
The molding table is immersed in the resin liquid to a depth corresponding to the thickness of the next light-cured layer. In this step, the molding table is temporarily immersed deeper than the depth. A resin liquid is supplied from the surroundings above the deeply sunk molding table, and after a sufficient amount of resin liquid is covered above the molding table, the molding table is raised to correspond to the thickness of the photocurable layer. Return to the depth position. During such lowering and raising of the molding table, the liquid level regulating means does not function, so that the resin liquid is not discharged, and the liquid level is allowed to be higher than the reference liquid level. So that After the lowering and raising of the molding table is completed, the liquid level regulating means is operated to discharge the resin liquid exceeding the reference liquid level.

[0015]

[Action] Conventionally, in order to maintain the liquid level of the liquid storage tank constant,
When the method of providing a drainage port is adopted, when the molding table is once deeply immersed and then raised and returned to a predetermined depth position, part of the required resin liquid is discharged. The present invention solves the problem that the liquid surface position fluctuates.

That is, in the step of lowering and raising the molding table, the liquid level regulating means such as the liquid discharge port is not operated so that the resin liquid is not discharged even if the liquid level rises above the reference liquid level. After the molding table has finished moving to a predetermined depth, the liquid level regulating means is activated to discharge the resin liquid exceeding the reference liquid level. As a result, even when the arm portion supporting the molding table pushes down the resin liquid when the molding table descends and the liquid level rises, the resin liquid is not discharged. Then, after the molding table is disposed at a predetermined depth position, if excess resin liquid exceeding the reference liquid level is discharged, a constant liquid level position, that is, the reference liquid level is always used in the step of irradiating the resin liquid with light. Will be maintained. As a result, the thickness of the resin liquid to be irradiated with light, that is, the thickness of the photocurable layer is accurately set.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows the entire structure of a three-dimensional shape forming apparatus, and a liquid storage tank 10 is shown.
Contains a photo-curable resin liquid 20, and a molding table 30 is submerged in the resin liquid 20. A plurality of photocurable layers 50 are stacked on the upper surface of the molding table 30. Molding table 30
Is connected to a drive mechanism installed outside the liquid storage tank 10 via the arm 32. As the driving mechanism, the same structure as that of the conventional example shown in FIG. 4 can be adopted. The operation of the drive mechanism is electrically controlled by a control device including an electronic circuit and the like.

Above the liquid storage tank 10, a laser beam irradiating device having an optical system 41 including a mirror and a condenser lens serving as a scanning mechanism and a lens group constituting a beam expander for adjusting a spot diameter is installed. And storage tank 1
A laser beam 40 is irradiated on the liquid surface of the zero. As the configuration of the optical system, the same configuration as the conventional example of FIG. 4 can be adopted.

As a liquid level regulating means, a drain port 18 is provided on one wall surface of the liquid storage tank 10. The outer surface of the drain port 18 is closed by a valve plate 70, and the valve plate 70 is moved up and down by a driving mechanism 72 such as a cylinder. As the valve plate 70 moves up and down, the drain port 18 is released or closed. The operation of the above device will be described. First, as shown in FIG.
Is closed, the molding table 30 is lowered. Molding table 3
The amount of decrease ΔX of 0 is the amount of the photocured layer 50 to be formed next.
Is set slightly larger than the depth corresponding to the thickness t. That is, the descending amount ΔX = t + α. Then, the liquid level of the resin liquid 20 rises as much as the arm 32 of the molding table 30 is inserted and pushed away. However, since the drain port 18 is closed, the resin liquid 20 is not discharged, and is maintained at the liquid level L higher than the reference liquid level L ₀ .

Next, by raising the forming table 30, to place the reference level L ₀ to the depth corresponding to the thickness t of the photocurable layer 50. At this time, the arm 3
2 is pulled up above the resin liquid 20, the volume of the arm 32 pushing the resin liquid 20 is reduced, and as a result,
The liquid level drops slightly. However, even at this stage, the reference liquid level L
_The liquid level L exists at a position higher than ₀ . After the movement of the forming table 30 has been completed, as shown in FIG. 3, when opening the drain port 18 by opening the valve plate 70, all the resin liquid 20 existing at a position higher than the reference liquid level L ₀ is drainage is exhausted from the mouth 18, the liquid level surely coincides with the reference liquid level L _0.

Thereafter, as shown in FIG.
If the irradiation to the liquid level of the laser beam 40, the laser beam 40 is well irradiated on the liquid surface which is the reference liquid level L _0, the thickness of the photocurable layer 50 formed is also set correctly. In the above embodiment, at liquid discharge port 18 and the valve plate 70 and also forms the liquid level regulating means, if adjusted liquid level in two stages of a position higher than a reference liquid level L _0, of the various structures weir Or a partition plate, a valve mechanism, or another liquid level control mechanism.

[0022]

According to the above-described method for forming a three-dimensional shape according to the present invention, by controlling the operation of the liquid level regulating means, the molding table is once sunk deeper than a predetermined depth position. Even if the method of raising the liquid level to the predetermined depth position is applied, the liquid surface position does not shift from the reference liquid surface, and the liquid surface position can be surely adjusted to the reference liquid surface.

As a result, the thickness of the photo-cured layer to be formed can be accurately set, and as a result, the dimensional accuracy and three-dimensional shape of the three-dimensional shape can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an embodiment of the present invention and illustrating a first step.

FIG. 2 is a sectional view showing a step subsequent to FIG.

FIG. 3 is a sectional view showing a step subsequent to FIG. 2;

FIG. 4 is a diagram showing a structure of a conventional example.

FIG. 5 is a sectional view showing the structure of another conventional example.

FIG. 6 is a sectional view showing an operation state.

FIG. 7 is a sectional view showing a state next to FIG. 6;

FIG. 8 is a cross-sectional view for explaining the effect of the arm portion of the molding table.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Storage tank 18 Drainage port 20 Photocurable resin liquid 30 Molding table 32 Arm part 40 Laser beam 50 Photocurable layer 70 Valve plate L ₀ Reference liquid level L Liquid level

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[Procedure amendment]

[Submission date] January 25, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

Thereafter, as shown in FIG. 7, when the molding table 3 is raised and positioned at a distance of ΔX from the reference liquid level L _0, that is, the lower end of the drain port 1 a, the arm portion 3 a of the molding table 3 Is partially withdrawn from the resin liquid 2, and the sixth
The arm portion 3 inserted in the resin liquid 2 is different from the state shown in the figure.
The volume of a, that is, the amount of the resin liquid 2 that has been pushed away by the arm portion 3a is reduced. Then, only became small amount of resin liquid 2 which is aside pushed by the arm portions 3a, lower the liquid surface of the resin liquid 2, the actual than the reference liquid level L ₀ of the person to the position of the drain port 1a The liquid level L drops.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

The difference ΔL between the liquid level L and the reference liquid level L ₀ is
The cross-sectional area S ₁ of the eighth arm portion 3a of the forming table 3 shown in FIG., From the cross-sectional area S ₁ excluding liquid resin 2 of liquid surface area S ₂ Prefecture of is calculated by the following equation. ΔL = α · (S ₁ / S ₂ ) (1) If S ₁ is negligibly small compared to S ₂ , the value of ΔL can be neglected. This greatly affects the thickness of the hardened layer 5 and the dimensional accuracy of the three-dimensional shape. In particular, when a high-precision three-dimensional shape is to be manufactured, a serious error occurs.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

[0011]

According to the present invention, there is provided a method for forming a three-dimensional shape, which comprises:
In the method of irradiating light to the liquid surface at each step to form a predetermined shape of the photocurable layer to form a desired three-dimensional shape by stacking a plurality of layers of the photocurable layer on the forming table, the storage tank , Bei liquid level regulating means for discharging the photocurable resin liquid exceeding the reference liquid level Eteoki, in the step of submerging the forming table, than a depth position corresponding to the thickness of the photocurable layer to temporarily object forming table After being immersed deeply, return to the depth position corresponding to the thickness of the target photo-cured layer, and during the above-mentioned step, the discharge of the resin liquid by the liquid level regulating means is stopped, and after the above-mentioned step, the liquid The resin liquid is discharged by the surface regulating means.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

As the liquid level regulating means, various liquid level regulating means employed for maintaining a constant liquid level in an ordinary liquid handling apparatus can be used. For example, the wall of the reservoir, if provided Open closed freely drain port and drainage weir like a position corresponding to the reference liquid level, while these drainage mouth, etc. is opened , All the resin liquid exceeding the reference liquid level is discharged,
When the drain port or the like is closed, it becomes possible to store the resin liquid to a liquid level higher than the reference level.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

[0023] As a result, the accurately set the thickness of the photocurable layer to be formed can thus dimensional accuracy of the three-dimensional shape, to improve the shape accuracy <br/> degree.

Claims (2)

[Claims] 1. A molding table is immersed stepwise in a liquid storage tank of a photocurable resin liquid, and a light-cured layer is formed by irradiating light to a liquid surface in each step, and a light-cured layer is formed on the molding table. A method of forming a desired three-dimensional shape by stacking a plurality of cured layers, wherein a liquid level regulating means for discharging a photocurable resin liquid exceeding a reference liquid level is provided in a liquid storage tank, and a step of sinking a molding table Then, after the molding table is once sunk deeper than the depth position corresponding to the thickness of the target light-cured layer, and returned to the depth position corresponding to the thickness of the target light-cured layer, A method for forming a three-dimensional shape, wherein the discharge of the resin liquid by the liquid level regulating means is stopped, and the resin liquid is discharged by the liquid level regulating means after the above step is completed. 2. The three-dimensional apparatus according to claim 1, wherein said liquid level regulating means comprises a drain port provided on a wall surface of the liquid storage tank, and a valve plate for selectively opening and closing the drain port. Forming method.