JPS61125824A - Extruding compression forming metallic mold - Google Patents

Abstract

PURPOSE:To improve the surface precision per capacity by a method wherein a pressurizing means respectively and independently pressurizing and controlling each movable mold is provided in addition to another pressurizing means pressu rizing multiple and movable molds evenly to supply pressurizing power required for molding. CONSTITUTION:When forming process is started, fixed molds 1 and movable molds 2 are closed to form two cavities 5. Firstly molten resin is extruded from a forming machine to fill both cavities 5 with the resin through a spool 10, a runner 12 and a gate 13. Secondary a pressurizing cylinder 7 and both fine adjustment pressurizing cylinders 16 are supplied with hydraulic power to pressurize the resin inside both cavities 5. At this time, the pressurizing cylinder 7 may supply the pressurizing power required for molding process while the fine adjustment pressurizing cylinders 16 may supply the pressurizing power required for the precision improvement.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an injection compression molding mold suitable for molding precision parts such as plastic lenses that require high precision in units of optical wavelengths.

[Background of the invention]

Injection molding, which is known as a type of plastic molding method, uses resin that has been melted and kneaded in a molding machine to be injected into a space inside a mold (
In this method, the resin is poured under high pressure into a cavity (hereinafter referred to as a cavity) and cooled over time within the cavity, but due to the nature of the resin, it always shrinks during cooling, so high precision in units of optical wavelengths such as plastic lenses etc. It is not suitable as a molding method for the required precision parts, and therefore, injection compression molding is generally adopted as a molding method for precision parts.

This injection compression molding method is basically the same as the above-mentioned injection molding method, but it is equipped with a pressurizing device such as a hydraulic cylinder in the mold, and the molten resin injected into the cavity is pressurized. Pressure is applied by a device to correct the shrinkage of the resin as described above, and is known as a method for molding precision parts such as plastic lenses, as described in, for example, Japanese Patent Laid-Open No. 57-187252.

FIG. 3 is a sectional view showing a conventional example of such an injection compression mold. In the figure, 1 is a fixed type, 2 is a movable type, 3 and 5 are fixed pieces fixed in the fixed type 1, and 4.4' are movable pieces fitted in the movable type 2 so as to be able to slide freely. Both input pieces 5.4 and 3.4 form a cavity 5.5'. 6 is a pressure plate that supports both movable Ikomashimas 4';
Reference numeral 7 denotes a pressure cylinder disposed at the rear of the pressure plate 6, and the pressure from the pressure cylinder 7 is applied to both cavities 5 and 5' via the pressure plate 6 and the movable insert piece 4.4'. Evenly transmitted. Reference numeral 8.9 denotes an extrusion plate that supports the pressure cylinder 7 and is integrally fixed thereto, and the suppression plates 8 and 9 are constructed so that a pressing force from a molding machine (not shown, the same applies hereinafter) acts on the suppression plates 8 and 9. ing.

10 is a sprue that guides resin from the molding machine (not shown, the same applies hereinafter) to both cavities 5.5', 11 is a sprue bush forming the outer periphery of the sprue 10, 12° 13 is a sprue 1
0 and cavity 5.5')
, 14 and 15 are mold mounting plates for attaching the main parts of these molds to the molding machine.

The operation of the injection compression mold constructed in this manner is as follows.

When molding begins, the fixed mold 1 and the movable mold 2 are first closed to form a cavity 5.5'. Next, the molten resin is injected into the molding machine 1, and the sprue 10 and runner 12 are injected.
1. When both cavities 5.5 are filled with resin through the gate 13, hydraulic pressure is then applied to the pressure cylinder 7 to pressurize the resin in both cavities 5, 5'.

After applying a pressing force of K to both cavities 5 and 5' for a certain period of time, the pressing force of the pressurizing cylinder 7 is removed, and the fixed mold 1 and the movable mold 2 are opened. Finally, move the extrusion plate 8 to the molding machine.
, 9 is applied with an extrusion force, and this force causes the extrusion plate 8.9
When the pressure cylinder 7, pressure plate 6, and both movable insert pieces 4.4 move forward, the resin, that is, the molded product, in both cavities 5.5' is pushed out. When the molded product is taken out in this manner, the fixed mold 1 and the movable mold 2 are closed again, and the above-described operation is repeated.

According to this conventional example, shrinkage of the resin in the cavity 5.5' can be corrected by the pressure applied from the pressure cylinder 7, so when molding a plastic lens, for example, the shape of the lens surface can be adjusted by changing the shape of the lens surface. It can be transferred as something similar to i5. However, both cavities are 5.5
Since the pressing force applied to each cavity 5, 5' is uniform, it is difficult to respond delicately to temperature changes in each cavity 5, 5'.

In other words, in the case of a large number of molded products (in which multiple molded products are molded at one time with one mold), the ambient temperature of each cavity differs slightly depending on its position), and the filling force of resin for each cavity varies. There is a slight difference in the sliding resistance of each movable insert piece, but the conventional example above cannot cope with the conditions of each cavity, and therefore the precision of each molded product varies. It has the disadvantage of causing

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an injection compression molding mold that can eliminate the drawbacks of the prior art described above and improve the accuracy of each molded product in a large number of molded products.

[Summary of the invention]

In order to achieve this object, the present invention provides a pressurizing means that can press each movable insert piece independently, in addition to a pressurizing means that applies pressure uniformly to each movable insert piece, and the former % in that it was possible to obtain the pressing force necessary for shaping by the means, and to obtain the fine pressing force necessary for improving the precision by the latter pressurizing means.
There are signs.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an injection compression mold according to an embodiment of the present invention, in which 16.15' is a pressure cylinder for fine adjustment;
7 is a regulator, and parts corresponding to those in FIG. 3 are given the same reference numerals.

The pressure cylinders 16 and 16' for fine adjustment are disposed between the pressure plate 6 and both movable insert pieces 4 and 4', and are fixed to the pressure plate 6 side. These fine adjustment pressure cylinders 16.16 are configured to be individually controlled by regulators 17, and the pressure from both fine adjustment pressure cylinders 16.16' is applied to both movable input pieces 4.4'. 5. Through both cavities. ,5'
transmitted to. In addition, fine adjustment pressure cylinders 16, 16
The pressurizing force from the pressurizing cylinder 7, which is placed behind the cavity 5, 5', is applied to both cavities 5, 5' and
C is transmitted. The other configurations are basically the same as the conventional injection compression mold described above.

In the injection compression molding metal 11 configured as described above, when molding is started, the fixed mold 1 and the movable mold 2 are closed to form the cavities 5, 5. Next, the molten resin is injected from the molding machine and placed on the sprue 10° runner 12. After the resin is filled into both cavities 5.5' through the gate 13, the pressure cylinder 7 and both fine adjustment pressure cylinders 16 are then filled.
, 16' are applied with hydraulic pressure, and the resin in both cavities 5, 5 is pressurized.

At this time, the pressurizing force necessary for shaping is generated by the pressurizing cylinder 7, and the fine pressurizing force necessary for improving precision is generated by the fine adjustment cylinders 16 and 16'. When the pressure is 50~1001/-, the pressurizing force of both fine adjustment pressure cylinders 16 and 16' is (L5~10Kg
/+l, which is smaller than the former. In this way, several pressurized cylinders 7.16 or 16 in one cavity.
' is provided because the pressurizing forces of the respective pressurizing cylinders cannot cover each other's pressure ranges, and as in this embodiment, the pressurizing cylinder 7 and the fine adjustment pressurizing cylinder 16,
By sharing the pressure range with K and 16', the pressing force necessary for shaping the resin in the cavity 5.5' and the minute pressing force necessary for improving accuracy can be obtained at the same time.

After the pressure applied to both cavities 5 and 5' is applied for a certain period of time in this way, the pressure applied to the pressure cylinder 7 and the fine adjustment pressure cylinders 16 and 16' is removed, and the fixed mold 1 and the movable mold 2 will be held. Finally, move the extrusion plate 8.9 to the molding machine.
An extrusion force is applied to the extrusion plate 8.9, the pressure cylinder 7, the pressure plate 6, and the pressure cylinder 16 for both fine adjustments.
, 16' and both movable insert pieces 4.4' move forward, the resin or molded product in both cavities 5.5' is pushed out. When the molded product is taken out in this manner, the fixed mold 1 and the movable mold 2 are closed again, and the above-described operation is repeated.

For example, when a plastic lens is molded using this embodiment, the surface precision can be improved from the conventional five interference fringes (1.5 μm) to two interference fringes (16 μm).
1. FIG. 2 is a sectional view of an injection compression molding die according to another embodiment of the present invention, and parts corresponding to those in FIG. 1 are given the same reference numerals. In the figure, 18.18'' is a pressure sensor that detects the pressure inside each cavity 5.5', and 19 is a pressure sensor 1' for these pressure sensors.
This is a controller that controls the pressure of the fine adjustment pressure cylinders 16 and 16', respectively, based on the measured values from the pressure cylinders 8 and 18'.

This embodiment differs from the first embodiment in that the resin pressure inside each cavity 5.5' is measured by each pressure sensor 1B, 1.
8' K is detected, and based on these detected values, 16'
By setting the O pressurizing force to an appropriate value, it is possible to further improve accuracy. At the same time, the variation in pressure force can be suppressed to within α5/-1.
In addition, it is possible to prevent internal cracks and surface peeling due to the application of excessive pressure, and the yield can be improved to 99 or more, which was limited to about 95 in the conventional technology.

In each of the above embodiments, an injection compression molding mold for molding two or more molds has been described, but it goes without saying that the present invention can be applied to molding for two or more molds.

In addition, the present invention is not limited to molding a large number of pieces of the same shape.
It can also be applied to molding of irregularly shaped parts whose shapes do not differ significantly.

〔Effect of the invention〕

As explained above, according to the present invention, in addition to the pressurizing means that uniformly pressurizes a plurality of movable inserting pieces to generate the pressing force necessary for shaping, each movable inserting piece is independently applied. Since a pressurizing means that can control the pressure is provided, the surface precision of each cavity can be improved.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of an injection compression mold according to an embodiment of the present invention, and Figure 2 is a cross-sectional view of an injection pressure network configuration according to another embodiment of the present invention.
FIG. 3 is a cross-sectional view of a conventional injection compression mold. 1...Fixed type 2...Movable type 3.3'...Fixed insert piece 4.4'...Movable insert piece 5.5... ... Cavity 6 ... Pressure plate 7 ... Pressure cylinder 8.9 ... Suppression plate 10 ... Sprue 11 ... Sprue bush 12...Runner 13...Gate 14.15...Mold mounting plate 16, 16'...Pressure cylinder for fine adjustment 17.
...Adjuster 18, 18'...Pressure sensor 19...
・Controller

Claims (1)

[Claims] It is equipped with a plurality of cavities, a plurality of movable insert pieces that can be moved back and forth corresponding to each cavity, and a pressurizing means for uniformly pressurizing each of these movable insert pieces, and the molten resin injected into each cavity is In an injection compression molding mold that pressurizes and shapes with an inserting piece, between the pressurizing means and each movable inserting piece,
An injection compression molding mold characterized by being provided with another pressurizing means that can independently control each movable inserting piece.