JP5326140B2 - Stereolithography equipment - Google Patents

Description

  The present invention relates to an optical modeling technique for optically producing a three-dimensional model by irradiating light to a liquid photocurable resin and photocuring it. In particular, the liquid level of the photocurable resin is adjusted to a predetermined position. Related to technology.

  2. Description of the Related Art In recent years, there has been known an optical modeling apparatus that manufactures a three-dimensional model by curing a photocurable resin based on data input to a three-dimensional CAD. This stereolithography technology is a model for verifying the appearance design in the middle of design, a model for checking the functionality of parts, a resin mold for producing molds, and a base model for producing molds. It attracts attention because it can easily manufacture complex three-dimensional objects such as.

  Generally, a method using a modeling liquid tank is employed for manufacturing a three-dimensional modeled object by an optical modeling apparatus. The procedure is as follows. After the liquid photocurable resin is put into the modeling liquid tank, firstly, a laser beam controlled by a computer is irradiated so that a desired pattern is obtained on the liquid surface of the modeling liquid tank. A photocured layer is formed by curing. Next, secondly, the photocuring layer is moved downward in the modeling liquid tank so that the photocurable resin flows on the photocuring layer, and an uncured photocurable resin layer is formed on the photocuring layer. Form. Third, the uncured photocurable resin is irradiated with laser light to form a photocured layer. Then, the first to third steps are repeated until a three-dimensional object having a predetermined shape and size is obtained to manufacture the three-dimensional object.

  In an optical modeling apparatus using a modeling liquid tank, in order to obtain a high-quality three-dimensional modeled object, it is necessary to always keep the liquid level of the modeling liquid tank constant during modeling. Therefore, in a conventional optical modeling apparatus, a predetermined volume of a block can be moved up and down with respect to a modeling liquid tank containing a photocurable resin, and the amount of block sinking into the photocurable resin is controlled, thereby providing a liquid. The height of the surface is maintained at a predetermined position. In addition to this, there is known an optical modeling apparatus that maintains the height of the liquid level at a predetermined position by moving the modeling liquid tank up and down.

However, when the block is moved up and down in the modeling liquid tank, it is necessary to provide a space for storing the block in the modeling liquid tank, the shape of the modeling liquid tank becomes complicated, and the modeling liquid is equivalent to the space for storing the block. The tank volume increases. When the volume of the modeling liquid tank increases, there is a problem that the cost increases because the amount of the photocurable resin increases accordingly.
Moreover, when the modeling liquid tank itself is moved up and down, the combined weight of the modeling liquid tank and the photocurable resin reaches several hundred kg (for example, 500 kg), so it is very difficult and efficient to control this weight with high accuracy. Not right.

  In addition to these conventional technologies, a liquid container is fixedly placed in a modeling liquid tank so that it can expand or contract, and liquid or gas is supplied to the container to increase or decrease the volume of the container. An optical modeling apparatus in which the height of a surface is maintained at a predetermined position has been proposed (see, for example, Patent Document 1). According to this stereolithography apparatus, since a movable mechanism for moving the block or the modeling liquid tank up and down is unnecessary, there is an advantage that the apparatus cost can be suppressed and the apparatus can be simplified.

JP 2000-52436 A

However, when the container is fixedly arranged in the modeling liquid tank, there are the following problems.
That is, when cleaning the modeling liquid tank for replacement of the photocurable resin or the like, if the container is fixed to the modeling liquid tank, it is troublesome to clean the fixed part. There is a problem that the conductive resin tends to remain.
Furthermore, the space directly above the container in the modeling liquid tank limits the height of the three-dimensional modeled object that can be manufactured due to the presence of this container, so depending on the height of the three-dimensional modeled object There is a problem that the space directly above the container becomes a dead space.

  The present invention has been made in view of the above-described circumstances, and it is possible to easily adjust the liquid level of the modeling liquid tank, and it is easy to clean the modeling liquid tank, and less space is wasted in the modeling liquid tank. An object of the present invention is to provide a stereolithography apparatus that can be used.

  In order to achieve the above object, the present invention forms a photocured layer by irradiating light onto a liquid photocurable resin that has entered a modeling liquid tank, and repeatedly forms the photocured layer by irradiating the light. Then, in the stereolithography apparatus for manufacturing a three-dimensional model, one or a plurality of balloons are placed in the modeling liquid tank, and a fixed regulating member that covers the balloon and regulates the floating is provided, or The balloon is provided with a weight for restricting ascent, and the liquid level of the modeling liquid tank is adjusted by inflating or reducing the balloon under the regulating member or on the floor surface of the modeling liquid tank. And

  Moreover, the present invention is characterized in that in the above-mentioned optical modeling apparatus, there is provided adjusting means for adjusting a fixed position of the regulating member to a plurality of depth positions of the modeling liquid tank.

  Further, the present invention is characterized in that, in the above-described stereolithography apparatus, a penetrating portion is formed in the restricting member so as to allow bubbles that have entered the lower side to escape upward.

According to the present invention, since the balloon placed in the modeling liquid tank is configured to be restricted by a fixed regulating member that covers the balloon or the weight, the balloon is easily taken out when the modeling liquid tank is washed. Can be cleaned easily.
In the modeling liquid tank, since the balloon is disposed under the regulating member or on the floor surface of the modeling liquid tank, the space above the balloon can be used as a modeling space. Less wasted space.

It is a figure which shows the external appearance structure of the optical modeling apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the structure for a modeling liquid tank and a liquid level adjustment. It is a figure which shows the fixed position adjustment of a control board. It is a figure which shows the relationship between the air supply / discharge time to a balloon, and the amount of vertical movements of a liquid level, (A) shows the relationship between air supply time and a liquid level rise amount, (B) shows air exhaust time and liquid level. The relationship with the surface descent amount is shown. It is a figure which shows the experimental result of the time which liquid level adjustment requires, (A) shows the experimental result of liquid level adjustment using a balloon, (B) shows the experimental result of the conventional liquid level adjustment using a block. . It is a figure which shows the structure for the modeling liquid tank and liquid level adjustment which concern on 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a diagram showing an external configuration of an optical modeling apparatus 100 according to the present embodiment.
As shown in this figure, the optical modeling apparatus 100 is roughly divided to irradiate the modeling liquid tank 10 filled with the liquid photocurable resin 2 (FIG. 2) and the light from above with respect to the photocurable resin 2. The light irradiation device 20 is provided. Inside the modeling liquid tank 10, the modeling table 11 is disposed so as to be moved up and down by the lifting mechanism 25.
As shown in FIG. 2, the modeling table 11 is disposed at a position that is lowered by a predetermined distance d from the liquid surface 12 of the liquid photocurable resin 2 that has entered the modeling liquid tank 10 when a three-dimensional model is manufactured. Then, on the surface of the modeling table 11, a liquid photocurable resin layer corresponding to one layer of the three-dimensional modeled object, that is, an uncured photocurable resin layer is formed.

When the optical modeling apparatus 100 manufactures a three-dimensional modeled object, the light irradiation device 20 controlled by a control computer (not shown) irradiates the liquid surface 12 of the modeling liquid tank 10 with light, so that the photocurable resin. The layer is photocured to form a photocured layer corresponding to one layer of the three-dimensional structure. Thereafter, the modeling table 11 is further lowered by a predetermined distance d to form an uncured photocurable resin layer for one layer on the upper surface of the previously formed photocured layer. By irradiating the liquid surface with light, a new photocured layer for one layer is newly formed on the previously formed photocured layer. When each photocured layer is formed, each photocured layer is formed in a predetermined pattern by the light irradiation device 20 irradiating the liquid surface with a predetermined pattern of light based on the modeling data of the three-dimensional object to be manufactured. The desired three-dimensional model is manufactured by laminating and forming such photocured layers. The modeling data is generated based on CAD data of each slice body when a three-dimensional model is sliced into a plurality of pieces.
During the modeling operation of the three-dimensional modeled object, the liquid level is adjusted so that the liquid level 12 of the modeling liquid tank 10 is positioned substantially at the reference liquid level. This liquid level adjustment will be described next.

FIG. 2 is a diagram schematically illustrating a configuration for liquid level adjustment of the modeling liquid tank 10.
The modeling liquid tank 10 has a substantially rectangular box shape, and is filled with a liquid photocurable resin 2. In addition, a balloon 30 that expands or contracts by supplying or discharging air is placed in the modeling liquid tank 10, and a regulating plate 31 is fixed as a regulating member that regulates the rising of the balloon 30. As the balloon 30 expands or contracts, the liquid level 12 of the modeling liquid tank 10 is adjusted.

The balloon 30 is a sealed bag body made of, for example, a resin film such as LLEDPE (linear low density polyethylene), and is not easily ruptured, for example, about 130 μm to 250 μm. The thickness is not so high.
Further, the balloon 30 is disposed in the approximate center of the modeling liquid tank 10 as viewed from above, and the time for the wave of the liquid surface 12 generated by the expansion or contraction of the balloon 30 to be settled is shortened. That is, even when the balloon 30 is inflated or contracted and the liquid level 12 is adjusted, the liquid level 12 quickly settles, so that the manufacturing time of the three-dimensional structure can be shortened.
If the balloon 30 is formed in a sheet shape that extends along the floor surface 10A of the modeling liquid tank 10, the time until the liquid level is stabilized can be further shortened. Moreover, since the height can be suppressed by making the balloon 30 into a sheet shape, the modeling liquid tank 10 can be made compact.

The restriction plate 31 is a plate member that is placed between the inner side surfaces on both sides of the modeling liquid tank 10, and has rigidity that resists the buoyancy of the balloon 30. For example, an aluminum plate having a thickness of about 5 mm can be used as the regulation plate 31.
Further, in the regulation plate 31, through holes 32 having a diameter of about 10 mm are formed in a lattice shape at a pitch of about 400 mm as penetrating portions penetrating the front and back surfaces. By providing these through holes 32, when the liquid photocurable resin 2 is put into the modeling liquid tank 10, the air that has entered the lower side of the regulation plate 31 can be quickly released to the upper side without accumulating. . Thus, since air does not accumulate under the regulation plate 31, the air accumulated in the regulation plate 31 does not float during manufacturing of the three-dimensional model and the production quality is not impaired.

  The fixing structure of the restriction plate 31 to the modeling liquid tank 10 will be described. On the inner surface of the modeling liquid tank 10, a pair of upper and lower restriction plate clamping members 33A and 33B that are positioned and fixed so as to sandwich the front and back of the restriction plate 31 are provided. Is provided. Since the restricting plate clamping members 33A and 33B sandwich the restricting plate 31, the vertical movement of the restricting plate 31 is restricted, and no play occurs when the balloon 30 is inflated or contracted. 12 disturbances are prevented.

  Here, when the regulation plate 31 is fixed in the modeling liquid tank 10, the effective depth of the modeling liquid tank 10 is defined by the fixing position of the regulation plate 31, and the height of the three-dimensional modeled object that can be modeled is limited. Will be. Therefore, the pair of regulating plate clamping members 33A and 33B are provided at a plurality of positions (three locations in the illustrated example) along the depth direction on the inner side surface of the modeling liquid tank 10, and the fixing position of the regulating plate 31 is fixed. Can be adjusted in multiple stages. Thereby, as shown in FIG. 3, the effective depth L of the modeling liquid tank 10 can be changed according to the height of the target three-dimensional molded item. Moreover, it is not necessary to manufacture the modeling liquid tank 10 according to each depth L separately.

  At this time, as shown in FIG. 3C and FIG. 3B, the three-dimensional modeling is performed on the lower side of the regulation plate 31 as the regulation plate 31 is fixed at a shallow position and the effective depth L is reduced. Unnecessary space that cannot be used for manufacturing space increases. Therefore, by increasing the number of balloons 30 according to the volume under the restriction plate 31 and arranging them in an overlapping manner, the volume of the balloon 30 occupying the volume under the restriction plate 31 is increased. The capacity of the photocurable resin 2 to be filled can be suppressed. In addition, in the modeling liquid tank 10 of this embodiment, since there is no useless space for arranging blocks and containers, the photocurable resin 2 can be used up more than before. Furthermore, when exchanging the photocurable resin 2, it can be exchanged after it has been used up, so the exchanging operation becomes easy. Note that a plurality of balloons 30 may be arranged side by side under the restriction plate 31 and a useless space under the restriction plate 31 may be filled with the balloon 30.

  As shown in FIG. 1, the optical modeling apparatus 100 includes a computer 50 as a configuration for controlling expansion and contraction of the balloon 30, and as shown in FIG. 2, a liquid level sensor 40, a pump 41, A supply solenoid valve 42, a discharge solenoid valve 43, and a pressure gauge 44 are provided.

The liquid level sensor 40 detects the position of the liquid level 12 and outputs it to the computer 50. As the liquid level sensor 40, an optical sensor using a red semiconductor laser is used. In the present embodiment, the liquid level sensor 40 having a resolution of 2 μm is used to adjust the height of the liquid level 12 with an accuracy of an allowable value (for example, ± 8 μm) with respect to the reference liquid level. .
The pump 41 is driven by the control of the computer 50 and sends air into the hose 45 connected to the balloon 30. As this pump 41, an electromagnetic air pump having a predetermined air volume per unit time (for example, 18 liters / min) is used.

The supply solenoid valve 42 is provided in the middle of the hose 45, opens under the control of the computer 50, opens when the pump 41 is driven, allows air to flow from the pump 41 to the balloon 30, and closes when the pump 41 stops. Thus, the outflow of air from the balloon 30 is blocked.
The discharge electromagnetic valve 43 is provided in the middle of a branch path 45A branched from the hose 45 and opened at the end, and is opened by the control of the computer 50 to discharge the air in the balloon 30.
The pressure gauge 44 is provided in the middle of the hose 45, detects the internal pressure of the balloon 30, and outputs it to the computer 50.

When a plurality of balloons 30 are placed in the modeling liquid tank 10, the hose 45 is branched and connected to each balloon 30, and the electromagnetic for selectively feeding the air supplied by the pump 41 to any one of the balloons 30. A valve may be provided in the branch path of each balloon 30.
In addition, a pump 41, a supply solenoid valve 42, a discharge solenoid valve 43, and a pressure gauge 44 are provided for each balloon 30 so that the expansion and contraction of each balloon 30 can be controlled independently of each other. The accuracy of surface adjustment can also be increased.

The computer 50 includes an analog-to-digital converter 51 that converts detection signals of the liquid level sensor 40 and the pressure gauge 44 into digital signals, and a pump 41, an electromagnetic for supply based on the detection results of the liquid level sensor 40 and the pressure gauge 44. And an I / O control unit 52 that controls each of the valve 42 and the discharge electromagnetic valve 43.
More specifically, when the I / O control unit 52 detects that the liquid level 12 has moved from the reference liquid level by an allowable value (for example, ± 8 μm) or more based on the detection result of the liquid level sensor 40, the liquid level 12. In order to keep the movement within the allowable value, the pump 41 is driven to open the supply solenoid valve 42 to inflate the balloon 30, or the discharge solenoid valve 43 is opened to shrink the balloon 30.

FIG. 4 is a diagram showing the relationship between the air supply / discharge time to the balloon 30 and the vertical movement amount of the liquid surface 12, and FIG. 4 (A) shows the relationship between the air supply time and the liquid level rise amount. 4 (B) shows the relationship between the air exhaust time and the liquid level lowering amount. The values shown in the figure are experimental values obtained under conditions of a room temperature of 23 ° C., a humidity of 45%, and a balloon pressure of 4 Pa.
As shown in the figure, there is a correlation between the air supply / discharge time to the balloon 30 and the amount of vertical movement of the liquid surface 12, and the liquid surface 12 is controlled by controlling the air supply / discharge time in ms units. It can be seen that can be controlled in units of μm.

The relationship between the air supply / discharge time and the amount of vertical movement of the liquid level 12 shown in FIG. 4 is converted into data and input in advance to the computer 50. When the computer 50 adjusts the liquid level 12, the air supply / discharge time during which the movement of the liquid level 12 is within an allowable value (for example, ± 8 μm) with respect to the reference liquid level is set based on the relationship shown in FIG. Then, the supply solenoid valve 42 / discharge solenoid valve 43 is opened for the air supply / discharge time to supply / discharge air to the balloon 30.
Next, the computer 50 determines whether or not the liquid level 12 has moved to a position within an allowable value from the reference liquid level based on the detection result of the liquid level sensor 40. If the liquid level 12 is within the allowable value from the reference liquid level, the computer 50 ends the liquid level adjustment operation. If the liquid level 12 is not within the allowable value from the reference liquid level, the computer 50 again determines the air supply / discharge time based on the relationship shown in FIG. 4, and similarly supplies / discharges air to the balloon 30. This operation is repeated until the liquid level 12 is within the allowable value from the reference liquid level.

  The computer 50 monitors the pressure of the balloon 30 with the pressure gauge 44 while supplying air to the balloon 30, and the pressure of the balloon 30 reaches a predetermined maximum pressure even before the air supply time is reached. Sometimes stop supplying air. When a plurality of balloons 30 are contained in the modeling liquid tank 10, the liquid level is adjusted by supplying air to the other balloons 30 that have not reached the predetermined maximum pressure.

FIG. 5 is a diagram showing experimental results of the time required for liquid level adjustment, FIG. 5 (A) shows the experimental results of liquid level adjustment of the present embodiment using the balloon 30, and FIG. 5 (B) is a block diagram. The experimental result of the conventional liquid level adjustment using is shown. This experimental result shows that the liquid level adjustment process for moving the liquid level 12 at a distance of ± 8 μm or more from the reference liquid level within ± 8 μm from the reference liquid level is performed about 1200 times, and the liquid level adjustment time required for each liquid level adjustment process Are plotted.
As shown in this figure, when the balloon 30 is used for liquid level adjustment, the average liquid level adjustment time is shortened compared to the case where a conventional block is used. Further, when the balloon 30 is used, the liquid level adjustment is completed within approximately 5 seconds, whereas when the conventional block is used, the liquid level adjustment may require 5 seconds to 10 seconds or more. Become more. In this way, the time required for three-dimensional object modeling can be shortened by shortening the liquid level adjustment time.

  Considering the reason why the liquid level adjustment time is shortened when the balloon 30 is used, when using a block, the block is usually moved up and down at the corner of the modeling liquid tank 10 so as not to disturb the modeling. When the balloon 30 is used, the volume of the balloon 30 increases or decreases in the center of the modeling liquid tank 10 while the wave generated on the liquid surface 12 during the vertical movement becomes non-uniform and the time until stabilization becomes long. Therefore, it is presumed that the waves generated on the liquid surface 12 are relatively uniform and the time until stabilization is shortened.

According to this embodiment described above, the following effects can be obtained.
That is, in the present embodiment, the balloon 30 is placed in the modeling liquid tank 10, and a fixed regulation plate 31 that covers the balloon 30 and regulates the floating is provided in the modeling liquid tank 10. The balloon 30 is expanded or contracted below to adjust the liquid level 12 of the modeling liquid tank 10.
According to this configuration, since the balloon 30 placed in the modeling liquid tank 10 is pressed by the fixed regulating plate 31 to restrict the rising, the regulating plate 31 is removed when the modeling liquid tank 10 is washed. Since the balloon 30 can be easily taken out, the washing operation of the modeling liquid tank 10 becomes easy.
Moreover, since the balloon 30 is arrange | positioned under the control board 31 in the modeling liquid tank 10, the space above the balloon 30 can be used for a modeling space, and there is little useless space in the modeling liquid tank 10 it can. Furthermore, since the amount of the photocurable resin filled in this useless space is reduced by the volume of the balloon 30, the amount of the photocurable resin that is wasted can be suppressed.

Further, in the present embodiment, the restriction plate clamping members 33 </ b> A and 33 </ b> B are provided at a plurality of locations along the depth direction of the modeling liquid tank 10, and the fixing position of the restriction plate 31 is set to the plurality of depth positions of the modeling liquid tank 10. Adjustable.
Thereby, the effective depth L of the modeling liquid tank 10 can be varied according to the height of the target three-dimensional modeled object, and it is not necessary to individually manufacture the modeling liquid tank 10 according to each depth L. . Furthermore, by disposing one or a plurality of balloons 30 so as to fill a useless space under the regulation plate 31, it is possible to suppress the amount of wasted photocurable resin.

  Further, in the present embodiment, since a large number of through holes 32 that allow the air bubbles that have entered the lower side to escape upward are formed in the surface in the regulating plate 31, air does not accumulate under the regulating plate 31. During the manufacturing process, the air accumulated on the regulation plate 31 does not float and the manufacturing quality is not impaired.

In the present embodiment, the following modifications are possible.
Although the plate-like restriction plate 31 is used as a restriction member that covers the balloon 30 and restricts flying, the present invention is not limited to this. That is, a mesh-like member having rigidity that can withstand the buoyancy of the balloon 30 may be used as the restricting member, or the restricting member may be configured by assembling a plurality of rod-like members in parallel or in a lattice shape.

  The adjustment means that enables the fixing position of the restriction plate 31 to be adjusted to a plurality of depth positions is realized by providing restriction plate clamping members 33A and 33B at a plurality of locations along the depth direction of the modeling liquid tank 10, respectively. However, it is not limited to this. That is, the fixing position of the restriction plate 31 may be adjusted steplessly by coupling the restriction plate 31 to a ball screw attached so as to extend in the depth direction of the modeling liquid tank 10.

[Second Embodiment]
FIG. 6 is a diagram illustrating a configuration of an optical modeling apparatus 200 according to the second embodiment. In addition, in the same figure, about the member similar to the optical modeling apparatus 100 of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.
As shown in this figure, in the present embodiment, the configuration is different in that the rising of the balloon 30 is not restricted by the restriction plate 31 in the modeling liquid tank 10 but is restricted by using a weight 35. The weight 35 is sealed in the bag in advance when the balloon 30 is manufactured, and is provided in a weight that resists the buoyancy of the balloon 30. The weight 35 may be tightly tied to the balloon 30 with a string or the like.

According to the present embodiment, similarly to the effect of the first embodiment, the balloon 30 can be easily taken out when the modeling liquid tank 10 is cleaned, so that the cleaning operation of the modeling liquid tank 10 is facilitated.
Moreover, since the balloon 30 is arrange | positioned on the floor surface 10A in the modeling liquid tank 10, the space on the balloon 30 can be used for a modeling space, and the useless space in the modeling liquid tank 10 can be reduced. .
In particular, according to the present embodiment, since the balloon 30 is positioned on the floor surface 10A, the depth from the liquid surface 12 to the balloon 30 can be increased.

The above-described embodiments merely show one aspect of the present invention, and can be arbitrarily modified and applied within the scope of the gist of the present invention.
For example, in each embodiment, the volume is changed by supplying air to the balloon 30. However, the present invention is not limited to this, and the volume may be changed by supplying a liquid.
The balloon 30 may be made of any material as long as the volume of the balloon 30 is variable in the liquid photocurable resin 2 in accordance with the supply / discharge of gas or / and liquid. Further, the shape of the balloon 30 is not limited to a sheet shape, and an arbitrary shape such as a rectangular parallelepiped shape or a spherical shape can be adopted.

2 photocurable resin 10 modeling liquid tank 10A floor 12 liquid level 30 balloon 31 regulating plate (regulating member)
32 Through hole (penetrating part)
33A, 33B Restricting plate clamping member (adjusting means)
40 Liquid Level Sensor 41 Pump 42 Electromagnetic Valve for Supply 43 Solenoid Valve for Discharge 44 Pressure Gauge 50 Computer 100, 200 Stereolithography Device

Claims (3)

In an optical modeling apparatus for manufacturing a three-dimensional model by irradiating a liquid photocurable resin in a modeling liquid tank with light to form a photocured layer, and repeatedly forming the photocured layer by irradiating the light. ,
Put one or more balloons in the modeling liquid tank, and provide a fixed restricting member that covers the balloon and restricts the floating, or a weight that restricts the rising of the balloon,
An optical modeling apparatus characterized by adjusting the liquid level of the modeling liquid tank by inflating or reducing the balloon under the regulating member or on the floor surface of the modeling liquid tank.   The optical modeling apparatus according to claim 1, further comprising an adjusting unit that adjusts a fixed position of the regulating member to a plurality of depth positions of the modeling liquid tank.   3. The stereolithography apparatus according to claim 1, wherein a penetrating portion is formed in the restricting member so as to allow bubbles that have entered the lower side to escape upward. 4.

Images