JP3785725B2 - Plastic lens manufacturing method and manufacturing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a manufacturing method and a manufacturing apparatus for molding a plastic product such as a plastic lens, and more particularly to a manufacturing method and a manufacturing apparatus suitable for a molding mold configured by assembling a plurality of molds with a tape or the like. .
[0002]
[Prior art]
As a plastic lens manufacturing method, a so-called tape molding method using an adhesive tape is known. In this method, a molding mold 5 as shown in FIGS. 1 and 2 is used. The molding mold 5 has two glass molds 1 and 2 each having a lens molding surface 1a and 2a as one surface, and the molding surfaces 1a and 2a facing each other at a predetermined interval. The two glass molds 1 and 2 are fixed and held so as to straddle the outer peripheral surfaces 1b and 2b of the molds 1 and 2 and the adhesive tape 3 is adhesively wound around the entire outer surfaces 1b and 2b of both glass molds. Formed. Then, a plastic lens raw material liquid that is polymerized and cured is injected into a space (cavity) 4 formed between the two glass molds 1 and 2, and is subjected to a treatment such as heating to be polymerized and cured. Molded.
[0003]
As a method for injecting a plastic lens raw material liquid (stock solution) into such a lens mold 5, a method of making an opening by partially peeling the adhesive tape 3 wound around the peripheral surfaces of the two glass molds 1 and 2. There is. In this method, a plastic lens is manufactured by the following process.
[0004]
1. The lens mold 5 formed by adhesively winding the adhesive tape 3 prepared in advance is manually peeled off a part of the adhesive tape 3 from the joining portion to form an opening.
[0005]
2. The tank filled with the plastic lens raw material solution and the injection pipe are connected via a filtration device or the like, and the tip of the injection pipe is put into the opening.
[0006]
3. The raw solution is injected into the cavity 4 using a device that injects the raw material solution into the lens mold 5 by means such as a pump or pumping.
[0007]
4). After the stock solution is filled in the cavity 4, the part from which the adhesive tape 3 has been peeled off is attached again to seal the cavity 4.
[0008]
5. Cure the stock solution.
[0009]
In addition, there is a method of injecting the stock solution by inserting the tip portion of the injection tube having a sharp tip through the adhesive tape 3 of the lens mold 5 and inserting it. Then, after filling the cavity 4 with the stock solution, a method is used in which the injection tube is pulled out, and the insertion port of the injected injection tube is attached with another adhesive tape or is closed by applying an adhesive.
[0010]
[Problems to be solved by the invention]
Conventionally, a series of operations for peeling off the adhesive tape 3 as described above, inserting an injection tube, and filling a resin is performed manually. If an operator touches this undiluted solution, the skin may be irritated, and if the stimulating odor of the undiluted solution is sniffed, it may make you feel unwell. For this reason, work is carried out using a drafter in a shut-off environment complete with facilities such as ventilation, or work is carried out with protective equipment such as glasses, a mask, and gloves. Therefore, the working efficiency is very poor, and this is one of the major factors that cannot reduce the manufacturing cost of plastic lenses. For this reason, it is an urgent task to automate the process of injecting the stock solution, and various automation methods and devices are being studied.
[0011]
Therefore, in the present invention, when automating the process of injecting the stock solution into the mold 5 in which the glass molds 1 and 2 are fixed with the adhesive tape 3 and the cavity 4 is formed, a product having a stable shape and good quality can be manufactured. An object of the present invention is to provide a plastic product manufacturing method and manufacturing apparatus. In molding molds in which multiple glass molds are fixed with adhesive tape, the adhesive tape often curves inward between the glass molds. When automated, the shape of the adhesive tape is corrected manually or curved adhesive The process of injecting the stock solution to make up the shape of the tape cannot be taken. Therefore, the stock solution cannot be completely filled in the molding mold, causing bubbles to be generated, or a product in the shape of the molding mold cannot be obtained, resulting in a failure in the subsequent manufacturing process. Is concerned. Therefore, in the present invention, in particular, when using a molding mold such as a mold for plastic lenses in which a mold is connected by a tape to form a cavity for injecting the stock solution, the stock solution due to the distortion of the tape is used. It aims at providing the manufacturing method and manufacturing apparatus which can prevent a filling defect.
[0012]
[Means for Solving the Problems]
For this reason, in the plastic product manufacturing method of the present invention, the injection solution is filled in the cavity without gaps by providing an injection hole in the vicinity of the wall-shaped mold that is prone to defective filling of the stock solution instead of the central portion of the tape. I can do it. That is, it is formed of a plurality of wall portions, and a mold for molding is formed by closing a cavity having an end width greater than 7 mm between the plurality of wall portions with a tape, and an injection hole is formed in the tape to inject a plastic stock solution to form. The plastic product manufacturing method of the present invention is characterized in that the injection hole is provided on at least one wall side of the wall portion rather than the center of the end width between the plurality of wall portions of the tape. In this way, since the stock solution can be injected into the cavity without gaps even if the tape is distorted or bent by injecting the stock solution from the wall side, it becomes possible to automate the process of injecting the stock solution, The working environment can be improved and the manufacturing cost can be reduced.
[0014]
In particular, the plastic product is a plastic lens, and the plurality of wall portions forming the molding mold are a first wall portion that defines the eyeball side surface of the plastic lens and a second wall portion that defines the object side surface. In the first step, the wall side of the first wall portion is more than the center of the end width between the first wall portion and the second wall portion of the tape in the first step. It is desirable to provide an injection hole in. Since the first wall portion has a convex surface protruding into the cavity, an injection hole is formed in the vicinity of the first wall portion so that the stock solution flows into the cavity while flowing along the convex surface. Accordingly, it is possible to manufacture a high-quality plastic lens without generating bubbles in the cavity.
[0015]
Further, by providing a step of measuring the distance between the first and second wall portions closed with the tape, the width of the cavity is automatically measured, so that the position for opening the injection hole is not mistaken. In addition, since it is not necessary to introduce the data of the molding mold from the outside, the manufacturing cost of the plastic product manufacturing apparatus can be reduced.
[0016]
Such a manufacturing method includes a mold holding device for supporting a molding mold formed by a plurality of wall portions and having a cavity in which an end width between the plurality of wall portions is larger than 7 mm, and a plurality of wall portions of the tape. It can be employed in a plastic product manufacturing apparatus having a drilling device capable of forming an injection hole for injecting a plastic stock solution into at least one wall side of the wall portion from the center of the end width therebetween. Further, in the plastic lens molding mold manufacturing apparatus, as described above, the injection hole extends from the center of the end width between the first wall portion and the second wall portion of the tape to the wall side of the first wall portion. Further, it is desirable to provide a measuring device that measures the distance between the first and second wall portions, so that malfunction can be prevented and the manufacturing cost of the manufacturing apparatus can be reduced.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 3 shows a planar arrangement of a plastic lens manufacturing apparatus 10 that automatically performs a process of injecting a plastic lens raw material liquid (raw solution) into a plastic lens molding mold. The molding mold 5 formed in advance so as to obtain a predetermined curvature, lens thickness, etc. with the configuration shown in FIGS. 1 and 2 is sequentially fed by the conveyor belt 9 in a horizontal state with the convex surface up. It will be. These molding molds 5 are simultaneously gripped (chucked) two by two by the mold supply device 11 and transferred to the measuring station 20. As will be described in detail later, in the measurement station 20, the molding mold 5 is set up vertically, the dial gauge is brought into contact with the outer peripheral surfaces 1b and 2b of the glass mold at the apex of the molding mold 5, and the tape 3 is put in this state. Move to cross. Then, the end width of the cavity 4 (the dimension corresponding to the edge thickness of the lens) 8 is calculated between the glass molds 1 and 2, depending on the position at which the tip of the dial gauge changes vertically when moving. In the manufacturing apparatus 10 of this example, the injection position of the stock solution is determined by the end width 8, and the injection pattern of the stock solution is further determined. Next, in the measuring station 20, the molding mold 5 is turned 180 ° in a vertically standing state, and an injection hole is opened from below. Thereafter, the molding mold 5 is set in a state in which it is turned 180 ° again and the injection hole faces upward.
[0018]
The molding mold 5 in which the injection hole is formed is transferred from the measuring station 20 to the transfer chuck 12a. The transfer chuck 20 is reciprocated linearly by the transfer belt 12. The transfer chuck 12 a moves the molding mold 5 from the measuring station 20 toward the injection station 50, and the molding mold 5 is held by the chuck 61 of the injection station 50. FIG. 4 shows an outline of an injection station 50 for injecting a plastic lens stock solution into the molding mold 5. In the injection station 50 of this example, a pressurized stock solution is supplied from a pressurized plastic lens raw material supply device housed in the lower part of the manufacturing apparatus 10 via a raw solution supply pipe 51, and the discharge amount of the raw material 59 is reduced. It is connected to a pin valve 52 to be controlled. A pulse motor 53 for changing the injection pattern is installed above the pin valve 52, and the flow rate and time of the stock solution injected into the cavity 4 of the molding mold 5 from the injection needle 54 provided at the tip of the pin valve 52 can be controlled. It is like that. The excess stock solution overflowing from the molding mold at the end when the stock mold 5 is filled with the stock solution is sucked by the suction nozzle 55 for vacuum suction and stored in the pressure-resistant bottle 56 connected to the vacuum generator 57. A capacitance sensor 58 that senses the presence or absence of the stock solution is provided between the piping connecting the suction nozzle 55 and the pressure bottle 56, and when the stock solution overflowed by the suction nozzle 55 is sucked, the pin valve 52 is turned off. The injection of the stock solution can be stopped automatically.
[0019]
The molding mold 5 into which the stock solution has been injected at the injection station 50 is rotated 180 ° horizontally by the rotary transfer means 60 while being held by the chuck 61 and moved to the sealing station 70. In the sealing station 70, a UV curable resin is applied to the injection port formed in the molding mold 5, and the UV resin is further cured by irradiation with ultraviolet rays. The molding mold 5 in which the injection port is sealed in this way is removed from the rotary transfer means 60. Then, it is placed in a horizontal state by the reversing chuck 15 and placed on a transfer device 90 for transfer to the pallet. The conveying device 90 is a robot for palletizing the molding mold 5 in which the stock solution is sealed onto a dedicated pallet 91 for thermal polymerization. Therefore, the manufacturing apparatus 10 of the present example can completely perform the process of injecting the stock solution into the supplied molding mold 5 and storing it in the dedicated pallet 91 by an unmanned operation.
[0020]
Below, the structure and process of the measurement station 20 of the manufacturing apparatus 10 of this example are demonstrated in more detail. As shown in FIG. 5, in the measurement station 20, the end width 8 of the molding mold 5 held in the vertical state by the chuck 29 is measured by the dial gauge 21. For this purpose, first, the tip 22 of the dial gauge 21 is set in contact with the outer peripheral surface 1b of the glass mold 1 defining the surface on the eyeball side, and the height is stored as the original position. Next, the dial gauge 21 is moved toward the outer peripheral surface 2 b of the glass mold 2 that defines the object-side surface so as to cross the adhesive tape 3. In this process, first, the place where the tip 22 of the dial gauge has dropped by about 0.1 mm is detected and stored as the boundary with the glass mold 1, that is, the starting point of the cavity 4. Further, the dial gauge 21 is moved in the direction of the glass mold 2, and the place where the tip 22 of the dial gauge is in the original position is detected and stored as the boundary with the glass mold 2, that is, the end point of the cavity 5. If the coordinates of the start point and the end point are known, the distance between them can also be known, so that the cavity end width 8 can be measured.
[0021]
In the manufacturing apparatus of this example, the injection pattern of the stock solution is determined by the end width (edge thickness) 8 thus measured, and the position of the injection hole is also determined. Accordingly, the manufacturing apparatus of this example can automatically perform the subsequent processing only by receiving the molding mold 5, and can perform work without acquiring design data of the molding mold 5. it can. Therefore, since it is not necessary to exchange design data and data for forming the molding mold 5, the configuration can be simplified, and the manufacturing cost of the manufacturing apparatus can be reduced. Further, since the subsequent processing can be managed with only the end width 8 for each of the supplied molding molds 5, the control system of the manufacturing apparatus can be simplified, and malfunction can be prevented. Therefore, it is possible to provide a manufacturing apparatus that can process at high speed and has high reliability.
[0022]
As shown in FIG. 6, the molding mold 5 whose end width 8 is measured is swung in the vertical direction so that the measured portion faces downward by 180 ° while being held by the chuck 29. Is formed. The perforating unit 25 can move in a direction along the end width 8 and is injected with compressed air heated to about 200 ° C. by an air heater at a predetermined position for about 0.1 to 1 second. 7 can be processed. The pressure of the compressed air and the air blowing time can be changed depending on the type of the adhesive tape and the processing area of the inlet. For example, a metal nozzle 26 with an inner diameter of 3 mm is attached to the tip of the perforation unit 25 and 2 to 4 kgf / compressed air is used, and the spraying time can be set to about 0.2 seconds.
[0023]
FIG. 7 shows a process of processing the injection hole 7 in the tape 3 using a flowchart. First, in step 31, the end width 8 is measured using the dial gauge 21. Next, the end width 8 measured in step 32 is determined. If the end width 8 exceeds 7 mm, the injection hole 7 is placed at a position 3 mm which is the minimum distance L from the inside of the glass mold 1 on the eyeball side in step 33. Is provided. On the other hand, if the end width is 7 mm or less, the injection hole 7 is provided at the center of the end width 8 in step 34. In the manufacturing apparatus 10 of this example, when the end width 8 is measured by the dial gauge 21, data of a reference point (measurement start point) inside the glass mold 1 is obtained. A hole is opened from the lower side at a position measured by the dial gauge 21 by rotating 180 °. Accordingly, the punching unit 25 moves accurately to a position away from the inside of the glass mold 1 by the minimum distance L based on the reference point measured by the dial gauge 21 or a predetermined punching position in the center of the tape 3. The injection hole 7 can be opened.
[0024]
FIG. 8 shows a state in which the stock solution 59 is injected into the cavity 4 from the injection hole 7 provided in the molding mold 5. The injection hole 7 is formed at a position close to the glass mold 1, that is, the glass mold defining the eyeball side surface when the end width 8 has a certain degree by the above process. Since the inner surface 1a of the glass mold 1 defines the surface on the eyeball side, it often has a convex shape that protrudes toward the inside of the cavity 4. Therefore, the injected stock solution 59 flows gently along the inner surface 1a of the glass mold 1. Therefore, the undiluted solution becomes turbulent during the injection and bubbles are generated in the undiluted solution 5, or the undiluted solution 5 is directly discharged to the tape 3 on the side opposite to the injection hole 7 and the tape 3 and the glass mold are discharged. It is possible to prevent troubles such as a gap between 1 and 2 and the stock solution 5 leaking out.
[0025]
FIG. 9 shows a state when the filling of the stock solution 59 into the cavity 4 is completed. As shown in FIG. 9A, the adhesive tape 3 wound around the outer peripheral surfaces 1b and 2b of the glass molds 1 and 2 is thin and has almost no rigidity. For this reason, in the vicinity of the outer peripheral surfaces 1b and 2b of the glass mold, the shape is almost the same as that of the glass mold. However, in the middle portion of the glass molds 1 and 2, that is, in the vicinity of the center of the end width 8, It is easy to generate. In most cases, as shown in FIG. 9, the tape 3 is curved so as to protrude toward the cavity 4, and the center portion of the end width 8 is recessed. Therefore, when the injection hole 7 is provided in the center portion of the end width 8 as shown in FIG. 9B, when the stock solution 59 overflows from the injection hole 7 and the injection is stopped, the portion in the vicinity of the glass molds 1 and 2 39 is not filled with the stock solution 59, and large bubbles are generated. If the lens is manufactured by sealing with UV curable resin in this state, the bubble moves to the center of the cavity 4 when the molding mold 5 is repositioned from the vertical state to the horizontal state, and a spherical surface as designed is obtained. It will not be possible. Although the resin may be polymerized in the vertical state, in this case, since there are large bubbles at the end (edge) of the lens, the shape of the lens does not become circular. Therefore, it becomes a hindrance in operations such as chucking the lens or taking out the center of the lens, and it becomes impossible to manufacture a high-quality spectacle lens with high accuracy.
[0026]
On the other hand, as shown in FIG. 9A, when the injection hole 7 is set in the vicinity of the first glass mold 1, an acute angle space above the cavity 4 formed by the glass molds 1 and 2 and the tape 3. The stock solution can be filled up to Therefore, defects such as air bubbles that directly affect the performance of the lens can be prevented in advance, and the edge of the lens is chipped, which hinders subsequent processing such as the center of the lens being unknown by the machine. Defects can also be prevented.
[0027]
Thus, it is desirable that the position of the injection hole is close to the glass mold, and further, it is desirable to provide the injection hole 7 in the vicinity of the glass mold 1 forming the eyeball side surface. However, if the injection hole 7 is too close to the glass mold 1 or 2, the injection needle 54 inserted from the injection hole 7 at the injection station 50 may collide with the inner surface 1 a of the glass mold 1. There is a possibility of damaging 1a. Therefore, in this example, the minimum distance L between the glass mold 1 and the injection hole 7 is set to 3 mm, and when the end width 8 is sufficient, the position of the injection hole 7 is determined regardless of the value of the end width 8. I can do it. If the end width 8 of the mold 5 is short, the minimum distance L from the glass mold 1 or the glass mold 2 may not be ensured. In this example, as shown in step 32 of FIG. 7, this corresponds to a case where the end width 8 having a margin of about 1 mm with respect to twice the minimum distance L is 7 mm or less. In contrast, the injection hole 7 is provided at the farthest distance from both the glass molds 1 and 2, that is, at the center of the end width 8. Of course, the minimum distance of 3 mm and the distance of 7 mm for ensuring the minimum distance are merely examples, and are determined in consideration of the thickness of the injection needle, the shape of the glass mold, and the penetration depth of the injection needle. be able to.
[0028]
In this way, when the stock solution injection hole 7 is opened in the molding mold 5 in which the glass walls 1 and 2 are connected by the tape 3, bubbles are generated as described above by opening as close as possible to the glass wall 1. It is possible to reliably mold an excellent plastic lens having no shape defect. Therefore, the injection process of the stock solution can be automated to mass-produce plastic lenses having sufficient performance without the operator having to check the state of bubbles one by one. Furthermore, by setting the minimum distance between the glass wall and the injection hole, the possibility of damaging the glass mold can be eliminated even if the injection process is automated. In addition, when the minimum distance cannot be secured, a process of providing an injection hole in the center of the tape 3 automatically sets the position of the injection hole for the molding mold 5 of any end width. It becomes possible to do.
[0029]
In this example, the present invention has been described in detail on the basis of a plastic lens manufacturing apparatus. However, in the tape molding method in which the wall portion and the wall portion of the mold are closed with tape to form a mold space (cavity), This applies not only to plastic lenses, but also to other products. By using the manufacturing method and manufacturing equipment that provide injection holes as disclosed above, problems such as the generation of bubbles and chipping of edges are prevented in advance. And it becomes possible to manufacture a product with good quality.
[0030]
【The invention's effect】
As described above, by using the manufacturing method and manufacturing apparatus of the present invention, the tape may be bent inward like a mold for molding a plastic lens in which a glass mold is closed with an adhesive tape. The injection process of the plastic stock solution can be automated even for the molding mold. For example, by forming an injection hole at a position separated from the glass mold on the eyeball side by a minimum distance, it is possible to prevent the production of a plastic product in which bubbles are generated or the shape is chipped. For this reason, according to the present invention, it is possible to completely automate the process of injecting the stock solution into the mold, and it is possible to automatically produce a high-quality plastic product free from bubbles and chipping. Therefore, according to the present invention, productivity can be increased, the manufacturing cost of plastic products can be reduced, and the manufacturing time can be shortened. In addition, by completely automating the injection process, it is possible to avoid problems in the working environment such as odors and gases of the plastic raw material liquid, reducing the cost of environmental measures, and reducing the labor of workers. can do.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an appearance of a plastic lens molding mold using a tape molding method.
2 is a cross-sectional view showing a configuration of a molding mold shown in FIG.
FIG. 3 is a plan view showing an outline of a plastic lens manufacturing apparatus according to the present invention.
4 is a diagram showing a schematic configuration of an injection station of the manufacturing apparatus shown in FIG. 3;
FIG. 5 is a diagram schematically showing how the cavity end width is measured at the measurement station of the manufacturing apparatus shown in FIG. 3;
6 is a view schematically showing a state in which an injection hole is opened at a measurement station of the manufacturing apparatus shown in FIG. 3. FIG.
7 is a flowchart showing a process for making an injection hole of the manufacturing apparatus shown in FIG. 3;
8 is a view showing a state when the injection of the stock solution is started from the injection hole in the manufacturing apparatus shown in FIG. 3;
9 is a view showing a state when filling of the stock solution is completed in the manufacturing apparatus shown in FIG. 3, and FIG. 9 (a) shows a case where an injection hole is provided near the glass mold, and FIG. ) Indicates a case provided in the center of the tape.
[Explanation of symbols]
1, 2 ·· Glass mold 1a, 2a ·· Molding surface 1b, 2b ·· Glass mold outer peripheral surface 4 ·· Cavity (space filled with stock solution)
5. Molding mold 7 Injection hole 8 End width (edge thickness)
10. ・ Manufacturing equipment 20 ・ ・ Measurement station 25 ・ ・ Drilling unit 29 ・ ・ Chuck 50 of measurement station ・ ・ Injection station 61 ・ ・ Chuck 70 of rotary ・ ・ Sealing station

Claims (2)

An end between the first wall and the second wall is formed by a first wall that defines an eyeball side surface of the plastic lens and a second wall that defines an object side surface. A molding mold is formed by closing a cavity having a width of more than 7 mm with a tape, and the wall side of the first wall portion is closer to the center of the end width between the first wall portion and the second wall portion of the tape. In the method of manufacturing a plastic lens, in which an injection hole is opened and a plastic stock solution is injected and molded,
Before the injection hole is provided in the tape, the distance between the first and second wall portions closed with the tape is measured. An end between the first wall and the second wall is formed by a first wall that defines an eyeball side surface of the plastic lens and a second wall that defines an object side surface. A mold holding device for supporting a molding mold in which a cavity having a width larger than 7 mm is covered with a tape;
A plastic having a punching device capable of forming an injection hole for injecting a plastic stock solution into the wall side of the first wall portion rather than the center of the end width between the first wall portion and the second wall portion of the tape. In the lens manufacturing equipment,
An apparatus for manufacturing a plastic lens, comprising: a measuring device for measuring an interval between the first and second wall portions.

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