JP2010208080A - Molding method and molding apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molding method and a molding apparatus suppressing defects in molding. <P>SOLUTION: When a first mold 10 and a second mold 20 are relatively moved to open and at the same time, a core 30 is shifted into a drawn state of being drawn to the second mold 20, air is caused to flow into a space between the core 30 and a molded optical element OE from the outside through a gap between an opening 20a and the core 30. That is, since one face molded by an optical face transfer face 10a and a flange part transfer face 10b in the optical element OE, and the other face molded by a optical transfer face 30a and a flange part transfer face 20b simultaneously come into contact with air and cooled, the cooling states of both faces become equal, thereby allowing highly precise molding. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a molding method and a molding apparatus, and more particularly to a molding method and a molding apparatus suitable for injection molding of an optical element.

  When an optical element is formed by resin injection molding, there is an advantage that optical elements having a highly accurate shape can be mass-produced. Here, the molded product in which the resin is solidified in a pair of molds that are clamped often sticks to one mold at the time of mold release, and some contrivance may be required to peel it off from the mold. . On the other hand, in Patent Document 1, after the mold release, the molded product attached to the mold is peeled off by pushing the vicinity of the gate of the molded product using an eject pin.

JP 2008-165019 A

  However, since the area near the gate of the molded product is generally small, it is necessary to use a thin eject pin, and if the adhesive force between the molded product and the mold is high, the vicinity of the gate may be broken by extrusion of the eject pin. As a result, the quality of the molded product may be deteriorated. In addition, the eject pin must be formed with high accuracy, which may increase the cost.

  On the other hand, a technique for taking out a molded product by providing a movable core with respect to a mold and protruding the core with respect to the mold after mold release has been developed. However, according to such a technique, when the core is protruded from the mold, the surface of the molded product (for example, the optical surface of the optical element) is pressed by the core. There is a possibility that the surface may be deformed by the pressing, and thereby it becomes impossible to obtain desired optical characteristics and the like. In addition, after molding, one mold remains attached to the resin when the mold is opened, so that the cooling state is not uniform on both sides, and it is difficult to obtain optical characteristics as designed in, for example, an optical element. is there.

  The present invention has been made in view of the problems of the prior art, and an object of the present invention is to provide a molding method and a molding apparatus that can suppress problems during molding.

The molding method according to claim 1 includes a first mold having a first molding transfer surface, and a second molding transfer surface facing the first molding transfer surface. A molding apparatus having a second mold relatively movable with respect to the core and a core that forms at least a part of the second molding transfer surface and is relatively movable with respect to the second mold is used. In the molding method
Injecting a resin between the first molding transfer surface and the second molding transfer surface after clamping the first mold and the second mold; and
Moving the first mold and the second mold in a direction away from each other after the resin has solidified,
Before or at the same time as moving the first mold and the second mold relatively away from each other, the core is moved relative to the second mold in a direction away from the first mold. It is characterized by.

  According to the present invention, the core is moved away from the first mold with respect to the second mold before the first mold and the second mold are moved relative to each other. Therefore, the remainder of the second molding transfer surface is separated from the solidified resin, thereby reducing the adhesive strength with the mold, so that the solidified resin can be easily taken out from the second mold. Become. According to the present invention, the first mold and the second mold are relatively moved in a direction away from each other, and at the same time, the core is moved with respect to the second mold. Since the one surface of the solidified resin is separated from the first transfer molding surface, the other surface of the solidified resin is separated from the rest of the second molding transfer surface. The difference in the cooling state on both sides is reduced as compared with the conventional case, whereby high-precision molding can be performed.

  According to a second aspect of the present invention, in the molding method according to the first aspect, the molding device includes an eject pin that can be protruded with respect to the second mold, and the core with respect to the second mold. Since the eject pin is protruded toward the solidified resin after or simultaneously with the movement of the mold away from the first mold, the molded product can be more easily removed from the mold using the eject pin. Can be peeled off.

  According to a third aspect of the present invention, there is provided the molding method according to the first aspect, wherein the core is solidified when the core is moved in a direction away from the first mold with respect to the second mold. Since air is introduced between the molded resin and the molded resin, the molded product can be taken out of the mold more easily.

The molding apparatus according to claim 4 is:
A first mold with a first molding transfer surface;
A second mold that includes an opening and a part of the second molding transfer surface facing the first molding transfer surface, and is movable relative to the first mold;
A core that forms the remainder of the second mold transfer surface and is disposed within the opening of the second mold and is movable relative to the second mold;
The second mold is provided with a vent for communicating the opening and the outside. The vent is shielded when the core is in the molding position, but the core is more than the molding position. Is also opened when moved to the retracted position side away from the first mold.

  According to the present invention, the second mold is provided with a vent for communicating the opening and the outside, and the vent is shielded when the core is in the molding position. Since the core is opened when the core moves to the retracted position side farther from the first mold than the molding position, the resin leaks out of the cavity during molding because the vent is shielded. Can be effectively suppressed. On the other hand, after the molding, when the core is moved in the direction away from the first mold with respect to the second mold, air is introduced from the outside through the opened vent to solidify. The core can be easily peeled off from the resin, and the solidified resin can be effectively cooled by the external cold air flowing in through the vent.

  ADVANTAGE OF THE INVENTION According to this invention, the shaping | molding method and shaping | molding apparatus which can suppress the malfunction at the time of shaping | molding can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a process of molding a lens as an optical element using a molding apparatus. The molding apparatus includes a first mold 10, a second mold 20, and a core 30.

  The first mold 10 has an optical surface transfer surface 10a and a flange portion transfer surface 10b. The second mold 20 has a cylindrical opening 20a formed at the center and a flange part transfer surface 20b facing the flange part transfer surface 10b of the first mold 10 around the opening 20a. A cylindrical core 30 is slidably disposed in the cylindrical opening 20a. The core 30 has an optical surface transfer surface 30 a facing the optical surface transfer surface 10 a of the first mold 10. The optical surface transfer surface 20a of the first mold 10 and the flange portion transfer surface 10b constitute a first molding transfer surface. The optical surface transfer surface 30a of the core 30 and the flange portion transfer surface 20b of the second die 20 are formed. And constitutes a second molding transfer surface. The curvature of the optical surface transfer surface 30a of the core 30 is preferably larger than that of the optical surface transfer surface 10a of the first mold 10.

  The first mold 10 is fixed, and the second mold 20 can be moved relative to the first mold 10 in the optical axis direction (left-right direction in FIG. 1) by a hydraulic cylinder (not shown) or the like. The core 30 is supported by the ball guide BG and can move in the optical axis direction with high accuracy with respect to the second mold 20.

  The second mold 20 has a pair of small openings 20c and 20c on both sides of the opening 20a. Eject pins 21 and 21 are disposed in the small openings 20c and 20c opened on the flange transfer surface 20b, and protrude from the flange transfer surface 20b by a hydraulic cylinder (not shown) or in the small openings 20c and 20c. It is configured to be pulled into.

(First molding method)
Next, a first molding method of the optical element will be described. First, the first mold 10 is set so as to face the second mold 20. In such an initial state, the core 30 is at the molding position of the second mold 20 (position shown in FIG. 1A), and the eject pins 21 and 21 are drawn into the small openings 20c and 20c. Thereafter, as shown in FIG. 1A, the first mold 10 is relatively approached and brought into close contact with the second mold 20, and the mold is clamped with a predetermined holding pressure.

  Further, by heating the first mold 10 and the second mold 20 with a heater (not shown), the optical surface transfer surfaces 10a and 30a at the time of mold clamping are heated to a predetermined temperature, and then the nozzle (not shown) gates. Resin is supplied in a state of being pressurized to an arbitrary pressure via GT.

  Next, after the molten resin is solidified in a state where the shapes of the optical surface transfer surfaces 10a and 30a and the flange portion transfer surfaces 10b and 20b are transferred, the mold temperature is lowered to cool and solidify the resin.

  Thereafter, in FIG. 1B, the core 30 is drawn into the second mold 20 before the mold is opened by relatively moving the first mold 10 and the second mold 20. Move to position. At this time, the optical element OE is supported by the flange portion transfer surface 20b of the second mold 20 regardless of the adhesive force between the optical surface transfer surface 30a of the core 30 and the molded optical element OE. The core 30 stays at that position without following the core 30, and the core 30 and the optical element OE can be efficiently separated. Furthermore, since air flows from the outside into the space between the core 30 and the molded optical element OE through the gap between the opening 20a and the core 30, the pull-in of the core 30 is hindered. There is no. By the above, compared with the case where the core 30 is extruded to the 1st type | mold 10 side, there is no possibility that the core 30 may deform | transform the optical surface of the optical element OE, and more highly accurate shaping | molding can be performed.

  In such a state, the molded optical element OE is almost in a state where only its flange portion is attached to the flange portion transfer surface 20b of the second mold 20, and it can be said that the adhesive force is weak. Therefore, as shown in FIG. 1 (c), when the eject pins 21 and 21 are projected from the small openings 20c and 20c, the tip presses the flange portion other than the optical surface of the optical element OE. The optical element OE can be easily peeled off from the second mold 20 by force. Compared with the normal pin extrusion method and core extrusion method, this method can disperse the force for releasing the optical surface and the force for taking out the molded product. Can be removed. The eject pins 21 and 21 may protrude at the same time as the mold opening of the first mold 10. Further, the operator may take out the optical element OE with tweezers or the like without using the eject pin.

(Second molding method)
Next, a second molding method of the optical element will be described. In contrast to the molding method described above, as shown in FIG. 1B, the first mold 10 and the second mold 20 are moved relatively to perform mold opening, and at the same time, the core 30 is moved to the second mold. The only difference is that the mold 20 is moved to the retracted position. At this time, air flows from the outside into the space between the core 30 and the molded optical element OE through the gap between the opening 20 a and the core 30. That is, one surface formed by the optical surface transfer surface 10a and the flange portion transfer surface 10b and the other surface formed by the optical surface transfer surface 30a and the flange portion transfer surface 20b in the optical element OE are simultaneously exposed to air. Since it is touched and cooled, the difference in the cooling state on both sides is reduced as compared with the conventional case, whereby high-precision molding can be performed.

  FIG. 2 is a schematic cross-sectional view of a molding apparatus according to a modification. The molding apparatus according to the modified example is different from the molding apparatus of FIG. 1 in that a vent 20d communicating with the opening 20a is formed on the side wall of the second mold 20. Since the other configuration is common, the description thereof is omitted.

  The vent 20 d is shielded by the outer peripheral surface of the core 30 when the core 30 is in the molding position (dotted line) with respect to the second mold 20, but the core 30 is molded with respect to the second mold 20. Immediately after starting to move from the position to the retracted position (solid line), it is provided at a position communicating with the space between the core 30 and the molded optical element OE. The vent 20d is preferably arranged with a phase different from that of the small openings 20c and 20c (for example, 90 degrees around the optical axis).

  According to the present modification, the vent 20d is shielded by the core 30 at the molding position during molding, so that it is possible to effectively prevent the resin from leaking from the cavity side via the vent 20d. On the other hand, when the core 30 is moved to the retracted state with respect to the second mold 20 before or simultaneously with the relative movement of the first mold 10 and the second mold 20 to perform mold opening. The air vent 20d is opened, so that air flows into the space between the core 30 and the molded optical element OE from the outside through the air vent 20d, so that the core 30 is pulled in more quickly. be able to.

  According to the present invention, it is possible to provide a molding method and a molding apparatus that can suppress problems during molding, but the object of molding is not limited to optical elements, and various products are targeted.

It is a figure which shows the process of shape | molding the lens as an optical element using a shaping | molding apparatus. It is a schematic sectional drawing of the shaping | molding apparatus concerning a modification.

DESCRIPTION OF SYMBOLS 10 1st type | mold 10a Optical surface transfer surface 10b Flange part transfer surface 20 2nd type | mold 20a Optical surface transfer surface 20a Opening 20b Flange part transfer surface 20c Small opening 20d Vent 21 Eject pin 30 Core 30a Optical surface transfer surface BG Ball Guide GT Gate OE Optical element

Claims (4)

A first mold having a first molding transfer surface and a part of a second molding transfer surface opposite to the first molding transfer surface and movable relative to the first mold. In a molding method using a molding apparatus having a second mold and a core that forms the remainder of the second molding transfer surface and is movable relative to the second mold,
Injecting a resin between the first molding transfer surface and the second molding transfer surface after clamping the first mold and the second mold; and
Moving the first mold and the second mold in a direction away from each other after the resin has solidified,
Before or at the same time as moving the first mold and the second mold relatively away from each other, the core is moved relative to the second mold in a direction away from the first mold. A molding method characterized by the above.   The molding apparatus has an eject pin that can be protruded with respect to the second mold, and after or simultaneously with moving the core away from the first mold with respect to the second mold, The molding method according to claim 1, wherein the eject pin protrudes toward the solidified resin.   The air is introduced between the core and the solidified resin when the core is moved away from the first mold with respect to the second mold. 2. The molding method according to 2. A first mold with a first molding transfer surface;
A second mold that includes an opening and a part of the second molding transfer surface facing the first molding transfer surface, and is movable relative to the first mold;
A core that forms the remainder of the second mold transfer surface and is disposed within the opening of the second mold and is movable relative to the second mold;
The second mold is provided with a vent for communicating the opening and the outside. The vent is shielded when the core is in the molding position, but the core is more than the molding position. The molding apparatus is also configured to open when moved to the retracted position side away from the first mold.

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