JPH01320114A - Molding method and device for radiation-cured resin - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method and apparatus for molding a molded article (such as a Fresnel lens) using a radiation-cured resin, such as an ultraviolet-cured resin, and particularly relates to a method and apparatus for molding a molded article (such as a Fresnel lens) using a radiation-cured resin, such as an ultraviolet-cured resin. The aim is to improve the accuracy of transfer of the surface to the molded product. The present invention relates to a method and apparatus for molding radiation-cured resin.

[Prior Art] Conventionally, the following three methods are known as methods for molding a Fresnel lens using this type of radiation-curable resin, such as an ultraviolet-curable resin.

Part 1. FIG. 10, which is described in Japanese Unexamined Patent Publication No. 177215/1982, is a schematic diagram showing a first example of a conventional molding apparatus for molding a Fresnel lens using an ultraviolet curable resin.

A cavity 37 is formed by an upper mold 35 on which a substrate 36 made of a transparent resin plate such as acrylic resin is mounted, and a lower mold 31 in which a cavity surface 32 is engraved in a shape opposite to that of the Fresnel lens surface. Then, the exhaust port 3 is removed by a vacuum pump.
While vacuuming the inside of the cavity 37 from 4, open the injection port 3.
When an ultraviolet curable resin is filled into the cavity 37 from 3, the resin is irradiated with ultraviolet rays from the ultraviolet irradiation device 38 and cured, and the cured prism portion is polymerized and adhered to the substrate 36 to form a Fresnel lens. Ru.

Part 2. FIG. 11, which is described in Japanese Unexamined Patent Publication No. 61-248708, is a schematic view showing a second example of a conventional molding apparatus for molding a Fresnel lens using an ultraviolet curable resin.

This is done by creating a gap of several meters between the mold 39a (the upper surface of which is carved in the opposite shape to the Fresnel lens surface) inside the mold body 39 and the acrylic resin substrate 36.
The substrate 36 is set in the mold body 39. Then, the valve 40 is opened and the gap is filled with ultraviolet curing resin. When the valve 40 is closed, the valve 41 is opened, and the resin is sucked by the suction force of the vacuum pump 42, a part of it is discharged into the trap 43, and the substrate 36 is moved into the mold 39a by its elasticity.
approach the Fresnel lens molding surface. In this state, mold 3
9a toward the cavity portion 44 side, the substrate 36 is returned to a flat surface, and the resin is irradiated with ultraviolet rays to be cured.
6 and polymerize and adhere.

If this molded product is released from the mold 39a, a desired Fresnel lens can be obtained.

Part 3. FIG. 12, which is described in Japanese Unexamined Patent Publication No. 61-248707, is a schematic view showing a third example of a conventional molding apparatus for molding a Fresnel lens using an ultraviolet curable resin.

A gap is provided between a plastic substrate 36 and a mold 39A on which a molding surface having a shape opposite to that of the Fresnel lens surface is formed, the back surface of the substrate 36 is supported by a reinforcing plate 45, and the gap is vacuumed. state. When this vacuum pressure is lower than that of the vacuum tank 46, the ultraviolet curing resin 47 in the vacuum tank 46 is filled into the gap. In this state, by irradiating the resin with ultraviolet rays from the ultraviolet irradiation device 38 and curing it, a desired Fresnel lens is molded.

[Problems to be Solved by the Invention] The above-mentioned conventional technology takes into consideration the fact that "sink marks" occur in the molded product due to curing shrinkage when the radiation-cured resin is cured, and that the transfer accuracy of the cavity surface to the molded product is poor. was not done. this is.

In optical components such as Fresnel lenses, this has caused deterioration in the optical performance of the optical components.

The present invention solves the problems of the prior art described above, and solves the problem of shrinkage caused by curing shrinkage when radiation-cured resin is cured.
The object of the present invention is to provide a method for molding a radiation-cured resin, which can prevent the above-mentioned problems and mold a molded product with excellent transfer accuracy, and a molding device that can be used directly to carry out this method.

[Means for Solving the Problems] In order to solve the above problems, the method for molding a radiation-cured resin according to the present invention has a structure including a thin base plate that transmits radiation;
A radiation-curable resin is filled into the cavity formed by the cavity surface of a mold whose cavity surface is engraved into a predetermined shape, and the resin is cured by irradiating radiation from the thin base plate side. ．． In the method of molding a desired molded product, the thin base plate is made of an elastic thin base plate, a sealed space is formed on the side opposite to the cavity of the thin base plate, and the volume of the cavity is reduced by vacuum suctioning the inside of this sealed space. The thin base plate is deformed in a direction opposite to the cavity so that the radiation cured resin expands by an amount equal to the amount of curing shrinkage filled into the cavity, and after filling the expanded cavity with the resin, the vacuum suction is applied. It was designed to be canceled.

In addition, the structure of the radiation-curable resin molding apparatus according to the present invention is such that the radiation-curable resin molding apparatus is configured such that the mold is inserted into a cavity formed by a thin base plate that transmits radiation and the cavity surface of a mold whose cavity surface is engraved into a predetermined shape. A radiation-curable resin is filled through a gate provided in the base plate, and the resin is irradiated with radiation from the thin base plate side to cure the resin, thereby forming a desired molded product, and mounting this molded product in the mold. In a molding device in which the mold is released by an ejector pin, the base thin plate is made into a base thin plate having a uniform elasticity, a sealed space is formed with this base thin plate on the side opposite to the cavity of the base thin plate, and the inside of the space is evacuated. The molding auxiliary device is equipped with a molding auxiliary device that can face the base thin plate and transmit radiation, a holding member that holds the plate material, and a vacuum suction device that can vacuum the inside of the sealed space. It is designed to have an exhaust port that allows air flow.

More details are as follows.

(1) Deform the thin base plate in advance using the elasticity of the thin plate so that the volume of the cavity increases by the amount of curing shrinkage of the radiation-cured resin, and after filling the resin, open the resin inlet and resin outlet. is shut off to prevent the cavity internal pressure from escaping, and then the force that was deforming the base thin plate is released. In this state, the above object is achieved by irradiating the resin with radiation such as ultraviolet rays.

(2) After filling the radiation-cured resin and releasing the force that was deforming the thin base plate, apply suction force (pressure greater than atmospheric pressure) to the thin base plate so that the cavity space becomes smaller than before. It would be even better if it were added and its size was controlled.

(3) It is even better to hold the thin base plate in the mold by inserting an O-ring or the like instead of the end face of the thin plate so that the surface of the O-ring is used to suction and hold the thin base plate to the mold.

(4) While holding down the outer periphery of the base thin plate to prevent air from escaping outside the mold, insert 1 between the outer periphery and the molded product.
It is even better if high pressure air is injected from a clearance provided around the countersunk ejector pin.

(5), the gate is in the radiation direction of the radiation.

It is even better if the gate is tapered in the drawing direction.

(6) The radiation-cured resin alone is vacuum degassed in advance,
It is even better if the mold is tilted 30" to 90 degrees and the resin is injected from below. At this time, in order to increase the resin injection speed, the inside of the mold should be slightly negative pressure. However, the pressure must not be higher than the vacuum degassing.And when curing the resin, it is better to return it to a horizontal position.

[Function] The respective functions of the means (1) to (6) described in the previous section are described below in correspondence with the relevant items.

(1) After filling the cavity with resin, the thin base plate, which had been deformed toward the side opposite to the cavity so that the volume of the cavity increases by the amount of curing shrinkage of the radiation-cured resin, closes the resin injection port and resin discharge port. In the disconnected state, the force that caused the deformation is released. The force is released on the base plate itself.

Due to its elasticity, a force that tries to return to its original state acts, and the filled resin is pressed down by this force, creating a positive pressure. In this state, the recording resin is irradiated with radiation such as ultraviolet rays to harden the resin. As the curing progresses, the resin shrinks, but the deformation of the thin base plate becomes smaller by the amount of curing shrinkage and returns to its original state, so that no defective transfer of the cavity surface to the molded product or "sink mark" occurs.

(2) After releasing the force that was causing the deformation of the thin base plate, when gravity is applied to the thin base plate in a direction that reduces the volume of the cavity, the pressure of the filled resin increases. If radiation such as ultraviolet rays is irradiated in this state, the resin shrinks not toward the radial center of the cavity but toward the outer periphery in the plate thickness direction and radial direction. Therefore, it is due to curing shrinkage towards the radial center. It is possible to eliminate the resin from sticking to the unevenness of the cavity surface, making it easier to release the molded product (especially in the case of a Fresnel lens).

(3) Since the base thin plate is suction-held to the mold by the O-ring on its surface, there is no restraint from the mold, unlike when the base thin plate is held at the end face of the thin plate.

Therefore, even if there are variations in the dimensions of the thin base plate, it will not interfere with attachment to the mold, and there will be no resin leakage or air leakage.

(4) The high-pressure air led from around the rainbow lid pin with zero plate enters between the uneven cavity and the hardened resin, and the high-pressure air may also escape from the outer periphery of the thin base plate to the outside of the mold. Therefore, the molded product can be reliably and easily released from the mold.

Further, during mold release, the thin base plate does not warp significantly and the mold release direction is perpendicular to the mold surface, so the mold can be released without damaging the surface of the molded product.

(5) The gate, which is tapered in the extraction gradient direction with respect to the radiation irradiation direction, has a hardening depth that differs depending on the radiation irradiation intensity and irradiation time, and there is a gap between the hardened part and the unhardened part. You can create boundaries. Therefore, the gate will not be undercut during demolding. Further, since the cured resin is smoothly released from the mold, there is no possibility that the cured resin will be injected during the first resin injection and cause a molded product to be defective.

(6) When resin is injected into the cavity, air caught in the resin at the tip of the flow of resin moves upwards of the tilted mold, that is, in the direction of the flow of resin. Therefore, the air will not remain in the cavity and will not form voids in the molded product. Furthermore, by returning the mold horizontally during curing, it is possible to eliminate the deviation of the resin due to gravity and to uniformly cure the resin.

[Example] The present invention will be described below with reference to an example in which a Fresnel lens used as a screen for a rear projection television is molded.

FIG. 1 is a cross-sectional view showing an example of a molding apparatus used to carry out the radiation-cured resin molding method of the present invention, and FIG.
FIG. 3 is a detailed cross-sectional view showing the vicinity of the countersunk ejector pin in FIG. 1, and FIG. 3 is a detailed cross-sectional view showing the vicinity of the tapered gate in FIG.

FIG. 4 is a schematic diagram showing a state in which the molding device according to FIG. 1 is attached to a press device.

First, the outline of this molding apparatus will be explained using FIGS. 1 to 3.

This molding device has a thin base plate that transmits ultraviolet rays and a cavity surface 1a having a predetermined shape (opposite shape to the Fresnel lens surface).
The cavity surface 1a of the Fresnel mold insert piece 1 engraved in
An ultraviolet curing resin is filled into the cavity 3 formed by the above through a gate provided in the lower mold 8 equipped with the Fresnel mold entry piece 1, and the resin is irradiated with ultraviolet rays from the thin base plate side to harden the resin. By curing, the cured prism portion and the thin base plate are integrally polymerized and bonded to form a desired molded product, and this molded product is released by an ejector pin attached to the lower mold 8, A Fresnel lens is obtained, and the base thin plate is made of an elastic base thin plate 2 (details will be described later).
on the anti-cavity side of.

A sealed space 16 is formed with this base thin plate 2, and the space 16
An upper mold 7 relating to a molding auxiliary device capable of creating a vacuum inside is mounted, and this upper mold 7 faces the thin base plate 2,
It has a plate material 4 (described in detail later) that transmits ultraviolet rays, a holding member 7a that holds the plate material 4, and an exhaust port 5 that can vacuum the inside of the closed space 16. serves as an air supply port through which a preset gas pressure can be introduced into the sealed space 16, and furthermore, the thin base plate 2 and the upper mold 7. Between the lower mold 8
A ring 6 is inserted, the gate is made into a tapered gate 9 having a taper in the direction of the ejection gradient, and the ejector pin is formed with a dish portion 12b having a taper in the direction of the ejection gradient at the tip of the shaft portion 12a. The plated ejector pin 12 is provided with a clearance 20 around the plated ejector pin 12, which communicates with an air pressure supply source (not shown).

This will be explained in detail below.

In the lower mold 8, a Fresnel mold insert piece 1 formed with a shape opposite to the Fresnel lens surface of a predetermined shape is attached to a vacuum exhaust port 1 for mold adsorption.
It is vacuum-adsorbed by vacuum suction from 1. A resin injection port 14 for injecting an ultraviolet curable resin is provided on one side of the lower mold 8, and communicates with the cavity 3 from the tapered gate 9 via a valve 10 in the middle. The second tapered gate 9, as shown in detail in FIG.
-1 and the uncured portion 9-2 can be separated at the boundary without undercutting, and has a taper angle in the same direction as the ultraviolet irradiation direction 13-1 and the mold release direction 12-1. That is, it has a taper in the direction of the extraction gradient, and the ultraviolet curing resin can be injected from below.

Further, on the other side of the lower mold 8, a discharge port 15 for overflowing the resin is provided via a valve 10 in the middle.

The plate material 4 is attached to the upper die 7, and the plate material 4 is made of glass (quartz or blue plate glass) that transmits ultraviolet rays. Moreover, between the upper mold 7 and the lower mold 8,
A thin base plate 2 is held via an O-ring 6. This base thin plate 2 is a transparent acrylic plate, and since its dimensions are large, 950 m x 750 m or more in a normal Fresnel lens, an extruded material is used in consideration of cost. The dimensional accuracy of its flatness is about ±0.5 mm, and the dimensional accuracy of the thickness direction is about ±0.inn. If such a thin base plate 2 is held in a normal manner, there is a risk of resin leakage or air leakage, so the flat part of the thin base plate 2 is tightly held by an O-ring 6 outside the cavity 3. The outer periphery is not fixed. In addition, dimensional variations in the thickness direction can be absorbed by the stroke of the press device, etc.

Above the plate material 4 of the upper mold 7, an ultraviolet irradiation device 13 for irradiating ultraviolet rays is attached to a swinging device (not shown) so that the entire area of the cavity 3 can be irradiated.

The dimensions of the cavity 3 do not directly affect the performance of the Fresnel lens, but in order to reduce the amount of ultraviolet curing resin used, it is best to make it as thin as possible without causing any problems during mold release. 0.3 including h (details later)
[The width was set in the range of 11 to 0.8 inches.

Between the thin base plate 2 and the plate material 4, the thin base plate 2 is deformed in advance in the direction opposite to the cavity so that an extra amount of resin can be filled into the cavity 3 by the amount of curing shrinkage of the ultraviolet curing resin. A closed space 16 is provided for this, and an exhaust port 5 for vacuum suction is connected to this closed space 16.

The ejector pin 12 with a plate used for releasing the molded product from the Fresnel mold insert 1 has a tapered plate part 12b at the tip of the shaft part L2a. A clearance 20 is provided between the shaft portion 12a and the shaft hole, and this clearance 20 communicates with the high pressure air supply port 21. Further, this clearance 20 is cut off from the outside air by an O-ring 24.

Moreover, as shown in FIG. 4, this molding device is held by a press device 25 in the vertical direction [the state shown in FIG. 4(a)] and the horizontal direction [the state shown in FIG. 4(b)]. It is now possible to do so.

By using the molding apparatus configured as described above, the present invention
A first example of a method for molding a radiation-cured resin will be described.

5 to 7 are for explaining the first embodiment of the molding method using the molding apparatus shown in FIG. 1, and FIG. FIG. 6 is a sectional view of a main part showing the operation of the ejector pin with one plate, and FIG. 7 is a sectional view.

FIG. 8, which is a sectional view showing a completed state of mold release, is a schematic diagram showing a Fresnel lens as a molded product. In each figure, the first
Parts with the same numbers as those in the figures are the same.

The press device 25 converts this molding device into the shape shown in FIG. 4(a).
), hold it vertically as shown.

By evacuating the sealed space 16 from the exhaust port 5 using a vacuum pump (not shown) in advance, the thin base plate 2 is lifted by a predetermined dimension and deformed toward the side opposite to the cavity (the state shown in FIG. 5). This amount of deformation is a value determined from the relationship between the curing shrinkage rate of the ultraviolet curable resin and the molding thickness of the resin. In this state, the valve 10 of the resin discharge port 15 and the valve 1o of the resin injection port 14 are opened, and a predetermined amount of acrylic resin is filled into the cavity 3 from the resin injection port 14 (the fourth
．． 5 injection direction 26). During resin filling, although some air is drawn in at the tip of the resin flow, there is no problem because the resin containing air at the tip overflows upward from the discharge port 15. After all the cavities 3 are filled with resin in this way, the single valve 10 is closed to prevent the resin from leaking.

Next, the vacuum pump that was drawing vacuum from the exhaust port 5 is stopped, and the inside of the sealed space 16 is returned to normal pressure.

The press device 25 is operated to return the molding device to the horizontal position [the state shown in FIG. 4(b)]. Irradiate ultraviolet rays with an irradiation energy of 500 mJ/aJ from the ultraviolet irradiation device 13,
The resin in the cavity 3 begins to harden. First, since the inside of the sealed space 16 was returned to normal pressure, the thin base plate 2, which had been deformed toward the side opposite to the cavity, is subjected to a force to return to its original plane due to its own elasticity. On the other hand, the resin cured by ultraviolet irradiation undergoes curing shrinkage, and along with this curing shrinkage, the deformation of the base thin plate 2 is recovered, and when the resin is completely cured, it becomes flat. When completely cured, the resin within the tapered gate 9 is divided into a cured portion 9-1 and an uncured portion 9-2, with a boundary formed between the two, as shown in FIG.

After opening the mold, the molded product is released by the ejector pin 12 with a plate. To explain this using FIG. 6, after moving the ejector pin 12 with a plate slightly upward, the high pressure air supplied from the high pressure air supply port 21 in the direction of the arrow is as follows.
It enters between the cured resin 22 and the Fresnel mold insert piece 1,
The molded product formed by the thin base plate 2 and the cured resin 22 (this is the prism part 18) being polymerized and bonded together is lifted up.

On the other hand, since the thin base plate 2 is compressed by the upper mold 7 and the lower mold 8 via the O-ring 6, the high-pressure air does not leak outside and flows sequentially toward the center of the molded product. The molded product is released from the mold. During this mold release, the thin base plate 2 is restrained at its outer edge, so that deformation is small. Therefore, the molded product is released from the mold in a direction substantially perpendicular to the Fresnel mold piece 1 over the entire Fresnel lens surface. The state when this template is completed is shown in FIG.

The Fresnel lens 27 molded in this way is the eighth
The details are shown in the figure [(a) is a plan view, (b)
The figure is a side view], size approximately 95011NIIX750mm
It has a thickness of approximately 3 mm, and is formed by polymerizing and bonding the thin body plate 2 and the prism portion 18 (details will be described later) together. The surface 17 of the prism section]8 has a height h,
Approximately 0.2'mn at the outer periphery.

0III in the center! Each prism is formed concentrically with a pitch of about 0.1 m, and the prism angle is about 60° at the outer periphery and 0° at the center.

According to the embodiment described above, there is a first-order effect.

(D) Since the cavity 3 is filled with the amount of curing shrinkage when the ultraviolet curable resin is cured by ultraviolet irradiation, "sinkage" of the molded product due to curing shrinkage and Fresnel mold insertion piece 1 transfer defects can be eliminated.

◎, thin base plate 2 and upper mold 7. Since the O-ring 6 is inserted between the lower mold 8 and the thin base plate 2 having a large area, it is possible to eliminate resin leakage and air leakage caused by variations in the dimensions of the thin base plate 2. can.

Clearance 2 around ejector pin 12 with 00 plate
Since the mold is released using high pressure air introduced into the Fresnel mold, the piece 1 inserted into the Fresnel mold can be removed without deforming the molded product.
The mold can be released in the vertical direction. Therefore, it is possible to eliminate resin residue on the cavity surface 1a having minute irregularities and to release the mold with high precision.

'-For p and m type, the part 9-1 cured by ultraviolet rays and the uncured part 9-2 can be separated without creating an undercut 1, which prevents undercut trouble during mold release and enables continuous molding. Make it.

■ Improved yield of molded products as molded product voids caused by air entrainment during resin injection are eliminated.

This improves the precision of molded products.

Next, a second embodiment of the method of molding a radiation-cured resin according to the present invention will be described with reference to FIG.

FIG. 9 is a schematic diagram showing the resin flow within the cavity for explaining a second embodiment of the molding method using the molding apparatus according to FIG. 1.

In the first embodiment, after filling the resin into the cavity 3, the vacuum suction of the vacuum pump connected to the exhaust port 5 was stopped to return the inside of the sealed space 16 to normal pressure. After stopping the vacuum pump, turn on the pressure regulator (not shown)
through a preset gas pressure, e.g. high pressure air,
The air is introduced into the closed space 16 through the exhaust port 5 (which also serves as an air supply port), and the inside of the space 16 is made into a positive pressure, which is maintained until the resin hardening is completed.

This will be explained using FIG. 9. FIG. 9(a) shows the case where the inside of the sealed space 16 is returned to normal pressure as in the first embodiment, and in this case, the thin base plate 2 No pressure is applied to. On the other hand, Figures (b) and (c) show the case of this embodiment in which the inside of the sealed space 16 is made positive pressure, and in both cases, pressure is applied to the base thin plate 2, and as a result, the inside of the cavity 3 The molten resin 23 is pressed.

Looking at this in detail, in the case shown in the figures (,), when the molten resin 23 hardens, it contracts toward the radial center of the cavity. The shape of the minute irregularities on the cavity surface 1a is
Since the rising portion is inclined toward the outer periphery, the resin moving toward the center in the radial direction may excessively move toward the rising portion, increasing the mold release force required to release the molded product. There is. On the other hand, (b), (
c) In the case shown in the figure, by creating a positive pressure in the sealed space, the molten resin 23 moves toward the radial outer periphery of the cavity and in the plate thickness direction, causing the resin to stick to the cavity surface.
can be prevented, and as a result, the mold release force can be reduced.

According to the second embodiment described above, in addition to the effects of the first embodiment described above, positive pressure is applied (or its magnitude is adjusted) in the closed space, so that the resin hardens. The direction of contraction is the thickness direction and the outer circumferential direction of the Fresnel lens, which has the advantage that the mold release force can be reduced and the transferability is further improved.

In addition, although each of the above-mentioned embodiments has been described with respect to molding a Fresnel lens, the present invention is also applicable to a lenticular lens,
It can be applied to the molding of optical discs, gratings, and other molded products made by integrally polymerizing and bonding a radiation-curable resin onto a thin base plate.

Furthermore, in each of the above Examples, a transparent acrylic plate was used as the thin base plate, but styrene, acrylic styrene polymer,
Any material may be used as long as it is made of transparent and elastic plastic such as polycarbonate or polymethylpentene.

Furthermore, in each of the above embodiments, a molded article is molded using acrylic resin, but it is not limited to ultraviolet curing resin such as acrylic resin, but also radiation curing resin such as γ-ray curing resin and X-ray curing resin. Needless to say, it can also be applied to molding using.

[Effects of the Invention] As explained in detail above, according to the present invention, it is possible to prevent "sink marks" caused by curing shrinkage when a radiation-cured resin is cured, and to mold a molded product with excellent transfer accuracy. can. A method of molding radiation-cured resins and a molding apparatus that can be used directly to carry out the method can be provided.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of a molding apparatus used to carry out the radiation-cured resin molding method of the present invention, and FIG.
FIG. 3 is a detailed cross-sectional view showing the vicinity of the dished ejector pin in FIG. 1, and FIG. 3 is a detailed cross-sectional view showing the vicinity of the tapered gate in FIG. FIG. 4 is a schematic diagram showing a state in which the molding device according to FIG. 1 is attached to a press device, and FIGS. 5 to 7 are a first embodiment of a molding method using the molding device according to FIG. 1. 5 is a cross-sectional view showing a state in which the thin base plate is deformed toward the side opposite to the cavity, FIG. 6 is a cross-sectional view of a main part showing the operation of the ejector pin with a plate, and FIG. 8 is a schematic diagram showing a Fresnel lens as a molded product, and FIG. 9 is a second implementation of the molding method using the molding apparatus according to FIG. 1. Schematic diagrams 10 to 12 showing the resin flow in the cavity for explaining an example are as follows:
FIG. 3 is a schematic diagram showing first to third examples of a conventional molding apparatus for molding a Fresnel lens using an ultraviolet curable resin. 1...Fresnel mold insert piece, 1a...cavity surface,
2... Base thin plate, 3... Cavity, 4... Plate material, 5... Exhaust port, 6... O-ring, 7... Upper mold,
7a... Holding member, 8... Lower die, 9... Tapered gate, 12... Ejector pin with plate, 12a...
・Shaft part, 12b...Dish part, 16...Closed space, 20
···clearance.

Claims (1)

[Claims] 1. A radiation-curable resin is filled into a cavity formed by a radiation-transmitting thin base plate and the cavity surface of a mold in which the cavity surface is engraved into a predetermined shape, and the substrate is injected into the resin. In a method of molding a desired molded product by curing the resin by irradiating radiation from the thin plate side, the thin base plate is made into a thin base plate having elasticity, and a sealed space is formed on the opposite side of the base plate to the cavity. , By vacuum suctioning the inside of this sealed space, the thin base plate is deformed to the side opposite to the cavity so that the volume of the cavity is expanded by an amount equal to the amount of curing shrinkage of the radiation-cured resin filled into the cavity, and this After filling the resin into the huge cavity,
A method for molding a radiation-cured resin, the method comprising releasing the vacuum suction. 2. The method for molding a radiation-cured resin according to claim 1, wherein the sealed space is maintained at a positive pressure from the time when the vacuum suction in the sealed space is released until the resin hardening is completed. . 3. A claim characterized in that when filling the radiation-curable resin into the cavity, the cavity is held at an angle of 30° to 90° with respect to the horizontal, and after filling, the cavity is held horizontally. 1. The method for molding a radiation-cured resin according to 1. 4. Fill a radiation-curable resin through a gate provided in the mold into a cavity formed by a thin base plate that transmits radiation and the cavity surface of a mold whose cavity surface is engraved into a predetermined shape. In a molding apparatus, a desired molded product is molded by curing the resin by irradiating radiation from the side of the base thin plate, and the molded product is released from the mold by an ejector pin attached to the mold. The thin plate is made into a thin base plate having elasticity, and a molding auxiliary device that can form a sealed space with this thin base plate on the side opposite to the cavity of the thin base plate and create a vacuum inside the space is attached to the thin base plate. The device is characterized in that it has a plate material that faces the thin base plate and is transparent to radiation, a holding member that holds the plate material, and an exhaust port that can vacuum the inside of the sealed space. , radiation curing resin molding equipment. 5. The radiation-curable resin molding apparatus according to claim 4, wherein the molding auxiliary device is provided with an air supply port through which a preset gas pressure can be introduced into the closed space. 6. The radiation-curable resin molding apparatus according to claim 4, wherein an O-ring is inserted between the thin base plate and the mold. 7. The radiation-curable resin molding apparatus according to claim 4, wherein the gate is a tapered gate having a taper in the draft direction. 8. A claim characterized in that the ejector pin is a countersunk ejector pin in which a countersunk portion having a taper in the extraction gradient direction is formed at the tip of the shaft portion, and a clearance is provided around the ejector pin that communicates with an air pressure supply source. Item 4. The radiation-curable resin molding apparatus according to item 4.