JP2000176944A - Method for producing plastic molded product and mold for molding plastic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mold a plastic molded product with high accuracy by making the adhesion strength with a resin of a cavity surface other than the molding surface of a movable core higher than that of the molding surface of the movable core. SOLUTION: A mold 1 for molding plastic has the cavity demarcated by a transfer surface 2, a molding surface other than the transfer surface and the molding surfaces 6 and 7 of movable cores 4, 5 and, at a time of molding, a molten resin is injected and charged in the cavity and, when the resin is cooled, the molding surfaces 6 and 7 of the movable cores 4 and 5 are moved in the direction separated from the resin to generate gaps between the molding surfaces 6 and 7 of the movable cores 4 and 5 and the cavity surface of a molded product but the adhesion strength with the resin of the cavity surface other than the molding surfaces 6 and 7 of the movable cores 4 and 5 is made relatively higher than that of the molding surfaces 6 and 7 of the movable cores 4 and 5 and the gaps are properly formed to form a highly accurate molded product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a plastic molded product and a mold for plastic molding, and more particularly, to a laser type digital copying machine, an optical scanning system of a laser printer or a facsimile machine, and a video camera. The present invention relates to a method of manufacturing a plastic molded product applied to an optical device, an optical disk, and the like, and a plastic molding die.

[0002]

2. Description of the Related Art An optical element such as a rectangular lens or a mirror having a function of forming an image of a laser beam and various corrections is used in an optical writing unit such as a digital copying machine, a printer and a facsimile machine of a laser system. I have.

In recent years, these optical elements have been changed from glass to plastic by injection molding due to a demand for reduction of manufacturing cost. The transfer surface shape has not only a spherical shape but also a complicated aspherical shape.

[0004] In the case of a lens, a lens having a thick lens shape having a large lens pressure and an uneven lens thickness in the longitudinal direction is often used.

[0005] Such a plastic molded product has a low production cost, is capable of moving an insert forming a transfer surface arranged in a mold or an injection molding method suitable for mass production, and is filled in the mold. Injection compression molding, which is a method for ensuring pressure accuracy by advancing the movable insert in response to volume shrinkage caused by cooling of the resin, to secure shape accuracy is used.

In these molding methods, it is generally desirable that the resin pressure and the resin temperature in the mold become uniform when the resin is cooled and solidified, in order to secure a desired shape accuracy in a molded product. .

[0007]

However, such a plastic molding method has heretofore had the following problems.

When a plastic molded product is manufactured by an injection molding method or an injection compression molding method, a resin pressure and a resin temperature in a mold are injected and filled in a mold by heating and melting, and then cooled and solidified. It is important that uniformity is obtained in order to secure desired shape accuracy.However, when molding a lens, if the lens has an uneven thickness having a thick portion and a thin portion in the lens thickness, the lens thickness may be reduced. The cooling rate of the filled resin differs due to deviation in each part in the longitudinal direction,
Due to the difference in volume shrinkage, shape accuracy deteriorates,
There is a problem that sink occurs at a thick lens. In addition, when the lens thickness is large, the shrinkage is likely to occur because the volume shrinkage is large in the cooling process of the resin,
If the injection pressure is increased in order to prevent the occurrence of sink marks, that is, if the filling amount of the resin is increased, the internal strain increases, which may adversely affect the optical performance.

When a plastic molded product is manufactured by the injection compression molding method, it is possible to mold the injection molding at a lower injection pressure than in the injection molding method. As a result, a difference occurs in the volume shrinkage, and the movable insert cannot follow the volume shrinkage of the resin, so that a uniform pressure cannot be applied. As a result, there is a problem that sink marks occur on a part of the transfer surface, and the shape accuracy cannot be ensured.

[0010] Such a problem is caused by separating the cavity piece (movable insert) from the resin when the mold is filled with the molten resin and then cooled to a temperature lower than the softening temperature, whereby the gap between the cavity wall surface and the resin is reduced. A gap is defined, and the shrinkage caused by cooling is absorbed by the movement of the resin in the portion facing the gap, so that the resin facing the gap is preferentially shrunk to prevent sink marks on the transfer surface. be able to.

However, when the resin is separated from the movable nest, the adhesive force between the movable nest and the resin is large, and a surface where it is desired not to generate a gap due to a peeling force generated when the resin is separated from the movable nest, for example, This causes a problem that the transfer surface is peeled off, sink marks are generated, and the entire shape of the molded product is deformed. As a result, there arises a new problem that the precision of the molded product is reduced.

Therefore, the invention according to claim 1 is a mold having at least one or more transfer surfaces and a molding surface of a movable insert movably provided as a cavity surface defining a cavity having a predetermined volume. When the molten resin filled in the cavity is cooled below the softening temperature, the cavity surface other than the molding surface of the movable insert is moved in a direction away from the resin to forcibly form a gap with the resin. By making the adhesive force between at least one cavity surface and the resin stronger than the adhesive force between the resin and the molding surface of the movable insert forming the void, the resin can be cooled when the resin is cooled. To prevent the shape from being deformed by being pulled by, forming a gap at the intended position, preventing sinking of the plastic molded product, and improving the shape precision of the plastic molded product. And its object is to provide a method of manufacturing a plastic article that.

According to a second aspect of the present invention, there is provided a mold cavity having at least one or more transfer surfaces and a movable insert molding surface movably provided as a cavity surface defining a cavity having a predetermined volume. When the molten resin filled in is cooled to the softening temperature or lower, the cavity surface other than the molding surface of the movable insert that moves in a direction away from the resin and forcibly forms a gap with the resin is formed. By making the adhesive strength between the resin and the cavity surface at the position facing the molding surface of the movable insert forming the gap stronger than the adhesive force between the molding surface of the movable insert forming the gap and the resin. Even when the cross-sectional area of the molding surface of the nest is large, it is possible to prevent the resin from being pulled by the movable nest when the resin is cooled and deforming the shape.
It is an object of the present invention to provide a method of manufacturing a plastic molded product that forms a void at an intended position to prevent sink of the plastic molded product and improve the shape accuracy of the plastic molded product.

According to a third aspect of the present invention, there is provided a mold cavity having at least one or more transfer surfaces and a movable insert molding surface movably provided as a cavity surface defining a cavity having a predetermined volume. When the molten resin filled in is cooled to the softening temperature or lower, the cavity surface other than the molding surface of the movable insert that moves in a direction away from the resin and forcibly forms a gap with the resin is formed. By making the adhesive force between at least one cavity surface and the resin stronger than the adhesive force between the molding surface of the movable insert forming the gap and the resin, the resin is pulled by the movable insert during cooling of the resin. A plastic mold that can prevent the plastic molded product from being deformed and form a void at the intended position, prevent sinking of the plastic molded product, and improve the shape accuracy of the plastic molded product. And its object is to provide a tick mold.

According to a fourth aspect of the present invention, there is provided a mold cavity having at least one or more transfer surfaces and a movable insert molding surface movably provided as a cavity surface defining a cavity having a predetermined volume. When the molten resin filled in is cooled to the softening temperature or lower, the cavity surface other than the molding surface of the movable insert that moves in a direction away from the resin and forcibly forms a gap with the resin is formed. By making the adhesive strength between the resin and the cavity surface at the position facing the molding surface of the movable insert forming the gap stronger than the adhesive force between the molding surface of the movable insert forming the gap and the resin. Even when the cross-sectional area of the molding surface of the nest is large, it is possible to prevent the resin from being pulled by the movable nest when the resin is cooled and deforming the shape.
It is an object of the present invention to provide a plastic molding die capable of forming a void at an intended position to prevent sink of a plastic molded product and improve the shape accuracy of the plastic molded product.

According to a fifth aspect of the present invention, by forming minute irregularities on the cavity surface for improving the adhesion, the adhesion is improved, and the anchor effect of the cavity surface for improving the adhesion is increased. Another object of the present invention is to provide a method of manufacturing a plastic molded product and a metal mold for plastic molding that can improve the adhesion at a low cost and improve the precision of the plastic molded product.

According to a sixth aspect of the present invention, the temperature of the cavity surface for improving the adhesive force is higher than the temperature of the molding surface of the movable insert forming the gap, thereby improving the adhesive force. It is an object of the present invention to provide a method for manufacturing a plastic molded product and a metal mold for plastic molding capable of appropriately and inexpensively improving the adhesion and improving the precision of the plastic molded product without performing any treatment.

According to a seventh aspect of the present invention, the molding surface of the movable insert forming the void is subjected to a surface treatment for reducing the adhesive force with the resin, so that the other cavity surface defining the cavity is brought into close contact with the resin. A plastic molded product capable of appropriately and inexpensively improving the adhesion and improving the accuracy of the plastic molded product by making the force relatively stronger than the adhesive force of the movable insert to the resin on the molding surface. It is an object of the present invention to provide a method of manufacturing a plastic molding die.

According to an eighth aspect of the present invention, the transfer surface is a cavity surface having a stronger adhesive force with the resin than with the resin with respect to the molding surface of the movable insert forming the gap. An object of the present invention is to provide a method for manufacturing a plastic molded product and a metal mold for plastic molding that can suppress generation of sink marks on a transfer surface and improve transfer accuracy.

According to a ninth aspect of the present invention, the reference surface for fixing the plastic molded product to another part is determined to have a smaller adhesive force between the resin and the molding surface of the movable insert forming the gap than the resin. A method of manufacturing a plastic molded product capable of suppressing the occurrence of sink marks on a cavity surface serving as a reference surface, and fixing a plastic molded product to another part with high precision by using a cavity surface that is strengthened. It is intended to provide a mold for plastic molding.

[0021]

According to a first aspect of the present invention, there is provided a method for manufacturing a plastic molded article, wherein a cavity surface defining a cavity having a predetermined volume is provided so as to be movable with at least one or more transfer surfaces. Filling the cavity of a mold having a movable insert molding surface with a molten resin heated to a softening temperature or higher, transferring the transfer surface to a molded product by a resin pressure of the molten resin, and transferring the resin. When cooling below the softening temperature, at least one or more of the movable inserts are moved in a direction away from the resin to forcibly form a gap between the resin and the molding surface of the movable insert. A method of manufacturing a plastic molded product, wherein at least one or more of the cavity surfaces other than the molding surface of the movable insert forming the gap is provided with a predetermined adhesion improving method. Ri, adhesion between the resin, by being stronger than the adhesion strength between the resin and the molding surface of the movable insert which forms the air gap, have achieved the above objects.

According to the above configuration, as a cavity surface defining a cavity having a predetermined volume, at least one or more transfer surfaces and a molding surface of a movable insert movably provided in a mold cavity. When cooling the filled molten resin to a temperature lower than the softening temperature, at least the cavity surface other than the molding surface of the movable nest that moves in a direction away from the resin and forcibly forms a gap with the resin. Since the adhesive force between one or more cavity surfaces and the resin is made stronger than the adhesive force between the molding surface of the movable insert forming the gap and the resin,
The resin is prevented from being deformed by being pulled by the movable nest during cooling of the resin, a gap can be formed at an intended position, and the occurrence of sink in a plastic molded product can be prevented. Shape accuracy of a plastic molded product can be improved.

According to a second aspect of the present invention, there is provided a method for manufacturing a plastic molded product, wherein at least one or more transfer surfaces and a molding surface of a movable insert movably provided as a cavity surface defining a cavity having a predetermined volume. Filling the molten resin heated above the softening temperature into the cavity of the mold having,
Transferring the transfer surface to the molded product by the resin pressure of the molten resin, when cooling the resin to a softening temperature or less, by moving at least one or more of the movable inserts in a direction away from the resin, A method of manufacturing a plastic molded product in which a gap is forcibly formed between the resin and the molding surface of the movable nest, wherein the cavity surface other than the molding surface of the movable nest forming the gap is formed. The cavity surface at a position facing the molding surface of the movable nest forming the gap, the adhesive force with the resin, the molding surface of the movable nest forming the void is formed by a predetermined adhesion enhancement method. The above object is achieved by making the adhesive strength between the resin and the resin stronger.

According to the above construction, as a cavity surface that defines a cavity having a predetermined volume, the cavity surface of the mold having at least one or more transfer surfaces and a movable nest forming surface movably provided. When the filled molten resin is cooled to a temperature lower than the softening temperature, the cavity is formed in a cavity surface other than the molding surface of the movable nest, which is moved in a direction away from the resin to forcibly form a cavity with the resin. The adhesive force between the resin and the cavity surface at the position facing the molding surface of the movable nest forming the resin is made stronger than the adhesive force between the molding surface of the movable nest forming the void and the resin. Even when the cross-sectional area of the molding surface is large, the resin can be prevented from being deformed by being pulled by the movable nest during cooling of the resin, and a void can be formed at an intended position. Prevents sinking Rukoto it is, it is possible to improve the shape accuracy of the plastic molding.

According to a third aspect of the present invention, there is provided a plastic molding die, wherein at least one or more transfer surfaces and a movable insert molding surface movably provided as a cavity surface defining a cavity having a predetermined volume. When the cavity is filled with a molten resin heated to a softening temperature or higher, the transfer surface is transferred to a molded product by the resin pressure of the molten resin, and when the resin is cooled to a softening temperature or lower. A plastic molding die for moving at least one or more of the movable inserts in a direction away from the resin to forcibly form a gap between the resin and a molding surface of the movable insert. Among the cavity surfaces other than the molding surface of the movable insert forming the gap, at least one or more cavity surfaces have an adhesion force with the resin by a predetermined adhesion force improving method. By being stronger than the adhesion strength of the molding surface of the movable insert which forms a gap between said resin, it has achieved the above objects.

According to the above construction, as a cavity surface defining a cavity having a predetermined volume, the cavity surface of the mold having at least one or more transfer surfaces and a movable insert molding surface movably provided. When cooling the filled molten resin to a temperature lower than the softening temperature, at least the cavity surface other than the molding surface of the movable nest that moves in a direction away from the resin and forcibly forms a gap with the resin. Since the adhesive force between one or more cavity surfaces and the resin is made stronger than the adhesive force between the molding surface of the movable insert forming the gap and the resin,
The resin is prevented from being deformed by being pulled by the movable nest during cooling of the resin, a gap can be formed at an intended position, and the occurrence of sink in a plastic molded product can be prevented. Shape accuracy of a plastic molded product can be improved.

According to a fourth aspect of the present invention, there is provided a plastic molding die having at least one or more transfer surfaces and a movable insert molding surface movably provided as a cavity surface defining a cavity having a predetermined volume. When the cavity is filled with a molten resin heated to a softening temperature or higher, the transfer surface is transferred to a molded product by the resin pressure of the molten resin, and when the resin is cooled to a softening temperature or lower. A plastic molding die for moving at least one or more of the movable inserts in a direction away from the resin to forcibly form a gap between the resin and a molding surface of the movable insert. The cavity surface at a position facing the molding surface of the movable nest forming the gap among the cavity surfaces other than the molding surface of the movable nest forming the gap is provided with a predetermined adhesion improving method. More, adhesion between the resin, by being stronger than the adhesion strength between the resin and the molding surface of the movable insert which forms the air gap, have achieved the above objects.

According to the above configuration, as a cavity surface defining a cavity having a predetermined volume, the cavity surface of the mold having at least one or more transfer surfaces and a movable insert molding surface movably provided. When the filled molten resin is cooled to a temperature lower than the softening temperature, the cavity is formed in a cavity surface other than the molding surface of the movable nest, which is moved in a direction away from the resin to forcibly form a cavity with the resin. The adhesive force between the resin and the cavity surface at the position facing the molding surface of the movable nest forming the resin is made stronger than the adhesive force between the molding surface of the movable nest forming the void and the resin. Even when the cross-sectional area of the molding surface is large, the resin can be prevented from being deformed by being pulled by the movable nest during cooling of the resin, and a void can be formed at an intended position. Prevents sinking Rukoto it is, it is possible to improve the shape accuracy of the plastic molding.

In each of the above cases, for example, as set forth in claim 5, the method for improving the adhesion is to improve the adhesion by forming minute irregularities on the cavity surface for improving the adhesion. There may be.

According to the above-described structure, minute irregularities are formed on the cavity surface for improving the adhesive force to improve the adhesive force. Therefore, the anchor effect of the cavity surface for improving the adhesive force is increased, thereby making it simple and inexpensive. The adhesion can be improved, and the accuracy of the plastic molded product can be improved.

Further, for example, as described in claim 6, in the method for improving the adhesion, the temperature of the cavity surface for improving the adhesion is made higher than the temperature of the molding surface of the movable insert forming the gap. May be increased to improve the adhesion.

According to the above construction, the temperature of the cavity surface for improving the adhesion is made higher than the temperature of the molding surface of the movable insert forming the gap, thereby improving the adhesion. Without this, the adhesion can be improved appropriately and inexpensively, and the accuracy of the plastic molded product can be improved.

Further, for example, as described in claim 7, in the method for improving the adhesion, the molding surface of the movable insert forming the gap is subjected to a surface treatment for reducing the adhesion to the resin. Alternatively, the adhesive force of the other cavity surface defining the cavity with the resin may be made relatively stronger than the adhesive force of the molding surface of the movable insert with the resin.

According to the above construction, the molding surface of the movable insert forming the gap is subjected to a surface treatment for reducing the adhesive force with the resin, so that the adhesive force with the resin on the other cavity surface defining the cavity is reduced. Since the adhesive strength of the movable insert to the molding surface is relatively stronger than the adhesive strength, the adhesive strength can be appropriately and inexpensively improved, and the accuracy of the plastic molded product can be improved.

Further, for example, as described in claim 8, the cavity having a stronger adhesive force with the resin than the resin with the molding surface of the movable insert forming the gap and the resin. The surface may be the transfer surface.

According to the above configuration, the transfer surface is a cavity surface having a stronger adhesive force with the resin than with the resin with the molding surface of the movable insert forming the gap.
The occurrence of sink marks on the transfer surface can be suppressed, and the transfer accuracy can be improved.

Further, for example, as described in claim 9, the cavity having a stronger adhesive force with the resin than the adhesive force between the molding surface of the movable insert forming the gap and the resin. The surface may be a reference surface when fixing the plastic molded product to another component.

According to the above configuration, the reference surface when fixing the plastic molded product to another part has a stronger adhesive force with the resin than the adhesive force with the molding surface of the movable insert forming the gap. Since the cavity surface is formed, sinks can be prevented from occurring on the cavity surface serving as the reference surface, and the plastic molded product can be fixed to other parts with high accuracy.

[0039]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. It should be noted that the embodiments described below are preferred embodiments of the present invention, and therefore, various technically preferable limitations are added. However, the scope of the present invention is not limited to the following description. The embodiments are not limited to these embodiments unless otherwise specified.

FIGS. 1 to 3 are views showing a first embodiment of a method for producing a plastic molded product and a plastic molding die according to the present invention.

FIG. 1 is a front sectional view of a main part of a plastic molding die 1 to which a first embodiment of a method for producing a plastic molded product and a plastic molding die according to the present invention is applied.

In FIG. 1, a plastic molding die 1 is shown.
In the figure, a cavity 8 is defined by a transfer surface 2, a molding surface 3 other than the transfer surface 2 and a cavity surface such as molding surfaces 6, 7 of two movable inserts 4, 5;
A gate for injecting and filling the molten resin material is formed in the gate.

The transfer surface 2 transfers a predetermined mirror surface to the molded product, and the movable inserts 4 and 5 have pressure controllers 9 and 10 for moving the movable inserts 4 and 5 in the direction of the cavity 8 and in the opposite direction.
Are connected. The molding surface 3 which is a cavity surface other than the molding surfaces 6 and 7 of the movable inserts 4 and 5 has an adhesion strength (adhesion force) between the molding surface 3 and the resin 11 (see FIG. 2) filled in the cavity 8. Are formed so as to be relatively stronger than the adhesion strength between the molding surfaces 6 and 7 of the movable inserts 4 and 5 and the resin 11. It should be noted that the surface of the movable inserts 4 and 5 whose adhesion strength to the resin 11 is stronger than that of the molding surfaces 6 and 7 is not limited to the molding surface 3 and may be, for example, the transfer surface 2. , At least one of the movable inserts 4 and 5 other than the molding surfaces 6 and 7
It suffices that the cavity surface of the surface has relatively higher adhesive strength with the resin 11 than the molding surfaces 6 and 7 of the movable inserts 4 and 5.

As a method of increasing the adhesion strength of the cavity 11 other than the molding surfaces 6 and 7 of the movable inserts 4 and 5 to the resin 11, for example, a method of forming irregularities on the cavity surface to increase the anchor effect is available. is there. This method, for example,
A physical method such as sandblasting, a method using a chemical corrosion action such as etching, or the like can be used.

As a method of increasing the adhesion strength of the cavity 11 other than the molding surfaces 6 and 7 of the movable inserts 4 and 5 to the resin 11, if other conditions such as members and roughness are the same, Taking advantage of the fact that the higher the surface temperature, the higher the adhesion strength between the resin 11 and the cavity surface, the temperature of the cavity surface other than the molding surfaces 6 and 7 of the movable inserts 4 and 6 is increased.
6 may be higher than the molding surfaces 6 and 7 to enhance the adhesion strength with the resin 11. This has been confirmed by experiments by the present applicant.

Further, the adhesion strength of the molding surfaces 6 and 7 of the movable inserts 4 and 5 to the resin 11 is determined by the molding surfaces 6 and 7 of the movable inserts 4 and 5.
The adhesive strength between the molding surfaces 6 and 7 of the movable inserts 4 and 5 is made weaker than the adhesive strength of the cavity 11 other than the cavity surface to the resin 11 and the molding surface of the movable insert 4 and 5 is reduced. The adhesion strength between the resin 6 and the resin 7 may be relatively higher than the adhesion strength. In this case, as a method of weakening the adhesion strength of the molding surfaces 6 and 7 of the movable nests 4 and 5, the molding surfaces 6 and 7 of the movable nests 4 and 5 are surface-treated with a material having a low adhesion strength with the resin 11. For example, TiN (titanium nitride), TiCN (titanium cyanide), W2 C (tungsten carbide), Teflon-based resin, or the like may be used to form the movable surfaces 4, 5 with molding surfaces 6, 7. Surface treatment method can be used.

The adhesive strength of the cavity 11 other than the molding surfaces 6, 7 of the movable inserts 4, 5 with the resin 11 is determined.
The method of forming irregularities on the cavity surface, the method of applying a temperature difference, and the method of performing surface treatment as a method of relatively increasing the adhesion strength of the molding surfaces 6 and 7 with the resin 11 of 5 are as follows.
The cavities other than the molding surfaces 6 and 7 of the movable inserts 4 and 5 may be used more reliably by using them alone or by using any two or more methods in combination. The surface of the movable inserts 4 and 5 can have a stronger adhesive strength to the resin 11 than the molding surfaces 6 and 7 of the movable inserts 4 and 5.

Next, the operation of the present embodiment will be described. The plastic molding die 1 has a cavity 8 defined by a transfer surface 2, a molding surface 3 other than the transfer surface, and molding surfaces 6 and 7 of two movable inserts 4 and 5. To mold a plastic molded product using the mold 1, first, the movable inserts 4, 5 are arranged at predetermined positions, and the pressure controllers 9, 10 are connected to each other, so that the molten material is melted in the cavity 8. The resin 11 is injection-filled. At this time, cavity 8
A pressure equal to or higher than the maximum resin pressure generated in the inside is applied to the movable inserts 4 and 5 by the pressure controllers 9 and 10, and the movable inserts 4 and 5 are fixed so as not to move by the injection pressure and transferred to the molded product. The surface 2 is transferred.

Subsequently, as shown in FIG.
Cooling and solidification of the resin 11 injected and filled in the resin progresses,
When the pressure of 1 decreases to a predetermined pressure, the molding surfaces 6 and 7 of the movable inserts 4 and 5 are moved in a direction away from the resin 11 (the direction indicated by the arrow in FIG. 2) to form the movable inserts 4 and 5. An air gap 12 is forced between the surfaces 6, 7 and the cavity surface of the part.

At this time, the adhesive strength of the cavity 11 other than the molding surfaces 6 and 7 of the movable inserts 4 and 5 of the plastic molding die 1 to the resin 11 is equal to that of the molding surfaces 6 and 7 of the movable inserts 4 and 5. Since the adhesive strength with the resin 11 is relatively stronger, the molding surfaces 6 and 7 of the movable inserts 4 and 5 and the cavity surface of the molded product 11 (hereinafter, the resin 11 is also referred to as a molded product house 11). The gap 12 is appropriately generated between the first and the second.

The resin 11 in the portion facing the gap 12 becomes easier to move than the portion facing the other cavity surface, and the shrinkage caused by cooling can be absorbed, and the transfer accuracy of the transfer surface 2 can be improved.

However, the molding surfaces 6, 7 of the movable inserts 4, 5
If the adhesive strength between the resin and the resin 11 is stronger than that of the other cavity surface, when the movable inserts 4 and 5 are moved in a direction away from the resin 11, as shown in FIG. Alternatively, in FIG. 3, the movable nest 5 is pulled by the movable nest 5 to form a gap 12 between the molding surfaces 6 and 7 of the movable nests 4 and 5 pulled by the resin 11 and the resin 11. Therefore, the resin 11 on the transfer surface 2 is peeled off. As a result, there arises a problem that the shape of the entire molded product 11 is deformed and a highly accurate molded product 11 cannot be produced.

However, as described above, the plastic molding die 1 of the present embodiment is different from the resin 11 on the cavity surface other than the molding surfaces 6 and 7 of the movable inserts 4 and 5 of the plastic molding die 1. The adhesion strength of the movable inserts 4, 5
Since the adhesive strength between the resin 7 and the resin 11 is relatively stronger, the resin 11 is fixed in the cavity 8 to prevent the resin 11 from being deformed by being pulled by the movable inserts 4 and 5. The gap 12 can be appropriately formed between the molding surfaces 6, 7 of the movable inserts 4, 5 and the cavity surface of the molded product. As a result, the shrinkage caused by cooling can be absorbed, and the transfer accuracy of the transfer surface 2 can be improved.
A highly accurate molded product 11 can be manufactured.

FIGS. 4 and 5 are views showing a second embodiment of the method for producing a plastic molded product and the plastic molding die of the present invention. FIG. 4 shows the production of the plastic molded product of the present invention. Method and Second of Plastic Mold
It is principal part sectional drawing of the metal mold | die 20 for plastic molding to which Embodiment of this invention was applied.

In FIG. 4, the plastic molding die 2
0 is the transfer surface 21, and the molding surfaces 22, 23 other than the transfer surface 21.
A cavity 26 is defined by the molding surface 25 of the single movable insert 24, and a gate (not shown) for injecting and filling a molten resin material into the cavity 26 is formed.

The transfer surface 21 transfers a predetermined mirror surface to the molded product, and the movable insert 24 is
A pressure control device 27 for moving in the direction and in the opposite direction is connected. The molding surfaces 22 and 23 which are cavity surfaces other than the molding surface 25 of the movable nest 24, particularly the molding surface 22 at a position facing the molding surface 25 of the movable nest 24 are the molding surfaces 2.
The adhesive strength (adhesion force) between the resin mold 28 and the resin 28 filled in the cavity 26 is formed to be relatively stronger than the adhesive strength between the molding surface 25 of the movable insert 24 and the resin 28. I have. The molding surfaces 22 and 23 other than the molding surface 25 of the movable nest 24 are made of resin 2 more than the molding surface 25 of the movable nest 24.
The method of increasing the adhesion strength to the contact member 8 is the same as the method of the first embodiment.

In the plastic molding die 20, the molding surface 22 which is a cavity surface facing the molding surface 25 of the movable insert 24 is a fixed surface, and at least the adhesion strength of the molding surface 22 to the resin 28. Is stronger than the adhesive strength between the molding surface 25 of the movable insert 24 and the resin 28.

The plastic molding die 2 of the present embodiment.
0 indicates that the molding surface 22 which is the cavity surface facing the molding surface 25 of the movable insert 24 is a fixed surface,
At least the adhesion strength of the molding surface 22 to the resin 28 is
Since the molding surface 25 of the movable nest 24 is stronger than the adhesive strength with the resin 28, even if the area of the molding surface 25 of the movable nest 24 is large, the molding surface 25 of the movable nest 24 can be appropriately adjusted.
A gap 29 is generated between the molded product 28 and the resin 28.
Accuracy can be improved.

That is, in the case of the plastic molding die 1 of the first embodiment, when the area of the molding surfaces 6 and 7 of the movable inserts 4 and 5 is large, as shown in FIG.
The cavity surface in the direction orthogonal to the molding surfaces 6 and 7 of the movable inserts 4 and 5, for example, the resin 11 on the transfer surface 2 or the molding surface 3
The molding strength of the movable inserts 4, 5 and the molding surface 6, 7 and the resin 1
5, the center of the molding surfaces 6 and 7 of the movable nests 4 and 5, and in FIG. 5, the center of the molding surface 7 of the movable nest 5 as shown in FIG. The resin 11 is pulled and deformed, and the gaps 12 are formed on the molding surfaces 6 and 7 of the movable inserts 4 and 5.
Is not formed, and the accuracy of the molded product may be deteriorated.

However, in the plastic molding die 20 of the present embodiment, as shown in FIG. 4, the molding surface 22 which is the cavity surface facing the molding surface 25 of the movable insert 24 serves as a fixed surface. In addition, at least the adhesive strength of the molding surface 22 to the resin 28 is greater than the adhesive strength of the molding surface 25 of the movable insert 24 to the resin 28. Therefore,
Even when the molding surface 25 of the movable nest 24 is large, the direction in which the molding surface 25 of the movable nest 24 is separated from the resin 28 (FIG. 4).
(In the direction indicated by the arrow in FIG. 3), a gap 29 is appropriately formed between the molding surface 25 of the movable insert 24 and the cavity surface of the molded product 28, and the molded product 28 is It can be prevented from being deformed by being pulled by the surface 25. As a result, the transfer accuracy of the resin molded product 28 can be improved.

In each of the above-described embodiments, the cavity surface which makes the adhesive strength to the resin 11 or 28 stronger than the molding surfaces 6 and 7 of the movable inserts 4 and 5 and the molding surface 25 of the movable insert 24 is used. When the transfer surface 2 and the transfer surface 21 are used, the adhesion strength between the transfer surface 2 and the resin 11 and the adhesion strength between the transfer surface 21 and the resin 28 are increased, and the occurrence of sink marks on the transfer surfaces 2 and 21 is suppressed. And a highly accurate transfer surface can be obtained.

Further, the cavity surfaces which make the adhesive strength with the resin 11, 28 stronger than the molding surfaces 6, 7 of the movable nests 4, 5 and the molding surface 25 of the movable nest 24, are formed in the other parts of the molded products 11, 28. When the reference surface is used as a reference surface at the time of fixing to the component, the adhesion strength between the cavity surface serving as the reference surface and the resin 11 or 28 is increased, and the occurrence of sink marks on the cavity surface serving as the reference surface can be suppressed. High transfer accuracy can be obtained. Therefore, the molded products 11 and 28 can be fixed to other parts with high positional accuracy.

Although the invention made by the inventor has been specifically described based on the preferred embodiments, the invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the invention. It goes without saying that it is possible.

[0064]

According to the method of manufacturing a plastic molded product according to the first aspect of the present invention, a movable insert movably provided with at least one or more transfer surfaces as a cavity surface defining a cavity having a predetermined volume. When the molten resin filled in the cavity of the mold having the molding surface of the child is cooled below the softening temperature, the molten resin is moved in a direction away from the resin to forcibly form a gap with the resin. Among the cavity surfaces other than the molding surface of the nest, the adhesive force between at least one cavity surface and the resin is made stronger than the adhesion force between the molding surface of the movable nest forming the void and the resin. The resin can be prevented from being deformed by being pulled by the movable nest at the time of cooling, a gap can be formed at an intended position, and the occurrence of sink of a plastic molded product can be prevented, It is possible to improve the shape accuracy of the plastic molded article.

According to the method of manufacturing a plastic molded product according to the second aspect, a molding surface of a movable insert movably provided with at least one or more transfer surfaces as a cavity surface defining a cavity having a predetermined volume. When the molten resin filled in the cavity of the mold having the following is cooled to a softening temperature or lower, the movable insert is moved in a direction away from the resin to forcibly form a gap with the resin. Of the cavity surfaces other than the surface, the adhesive force between the resin and the cavity surface at the position facing the molding surface of the movable nest forming the gap is determined by the adhesive force between the molding surface of the movable nest forming the void and the resin. To prevent the resin from being pulled by the movable nest while the resin cools and deforming the shape, creating a gap at the intended position even when the molding area of the movable nest is large. Can be It is possible to prevent the occurrence of shrinkage of the stick molded article, it is possible to improve the shape accuracy of the plastic molding.

According to the third aspect of the present invention, as a plastic molding die, a movable surface is formed so as to be movable with at least one or more transfer surfaces as a cavity surface defining a cavity having a predetermined volume. When the molten resin filled in the cavity of the mold having a surface is cooled to a softening temperature or lower, the movable insert is moved in a direction away from the resin to forcibly form a gap with the resin. Of the cavity surfaces other than the molding surface, the adhesive force between at least one or more cavity surfaces and the resin is made stronger than the adhesive force between the molding surface of the movable nest forming the voids and the resin, so that the resin is cooled. The resin is prevented from being deformed by being pulled by the movable nest, a gap can be formed at an intended position, and the occurrence of sink in a plastic molded product can be prevented. It is possible to improve the shape accuracy of the click moldings.

According to the fourth aspect of the present invention, at least one or more transfer surfaces are movably provided as a cavity surface defining a cavity having a predetermined volume. When the molten resin filled in the cavity of the mold having a surface is cooled to a softening temperature or lower, the movable insert is moved in a direction away from the resin to forcibly form a gap with the resin. Among the cavity surfaces other than the molding surface, the adhesive force between the resin and the cavity surface at a position facing the molding surface of the movable nest forming the gap, and the adhesion force between the molding surface of the movable nest forming the gap and the resin. Even if the cross-sectional area of the molding surface of the movable insert is large, it is possible to prevent the resin from being pulled by the movable insert when the resin cools and deforming the shape, and to create a gap at the intended position. Can be formed It is possible to prevent the occurrence of shrinkage of the stick molded article, it is possible to improve the shape accuracy of the plastic molding.

According to the method for manufacturing a plastic molded product and the mold for plastic molding according to the fifth aspect, the adhesion is improved by forming minute irregularities on the cavity surface for improving the adhesion, thereby improving the adhesion. By increasing the anchor effect of the cavity surface to be formed, the adhesion can be improved simply and inexpensively, and the precision of the plastic molded product can be improved.

According to the method for manufacturing a plastic molded product and the mold for plastic molding according to the sixth aspect, the temperature of the cavity surface for improving the adhesion is set higher than the temperature of the molding surface of the movable insert forming the gap. As a result, the adhesion is improved, so that the adhesion can be appropriately and inexpensively improved without performing treatment on the cavity surface, and the precision of the plastic molded product can be improved.

According to the method for manufacturing a plastic molded product and the mold for plastic molding according to the seventh aspect, the molding surface of the movable insert forming the void is subjected to a surface treatment for reducing the adhesive force with the resin, and the cavity is formed. Since the adhesive force with the resin of the other cavity surface defining the cavity is relatively stronger than the adhesive force with the resin of the molding surface of the movable insert, the adhesive force can be appropriately and inexpensively improved. In addition, the accuracy of a plastic molded product can be improved.

According to the method for manufacturing a plastic molded product and the mold for plastic molding according to the eighth aspect, the transfer surface is
Since the cavity surface is formed so that the adhesive force with the resin is stronger than the adhesive force between the molding surface of the movable insert forming the gap and the resin, it is possible to suppress the occurrence of sink marks on the transfer surface. Accuracy can be improved.

According to the method for manufacturing a plastic molded product and the metal mold for plastic molding according to the ninth aspect, the reference surface when fixing the plastic molded product to another component is used as the molding surface of the movable insert forming the gap. Because the cavity surface has a stronger adhesive force with the resin than the adhesive force with the resin, it is possible to suppress the occurrence of sink marks on the cavity surface serving as the reference surface, and to use plastic molded products as other parts. It can be fixed with high precision.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a main part of a plastic molding die to which a first embodiment of a method for producing a plastic molded product and a plastic molding die according to a first embodiment of the present invention is applied.

FIG. 2 is a front sectional view of a main part in a state where a movable insert is moved in a direction away from the cavity after the cavity of the plastic molding die of FIG. 1 is filled with resin.

FIG. 3 is a diagram showing a case where resin is not applied to the movable insert when the cavity surface other than the molding surface of the movable insert of the plastic molding die in FIG. The principal part sectional view which shows the state which was pulled.

FIG. 4 is a front sectional view of a main part of a plastic molding die to which a second embodiment of the method for producing a plastic molded product and the plastic molding die according to the present invention is applied.

FIG. 5 is a front cross-sectional view of a main part of the plastic molding die of FIG. 1 in a case where the molding surface of the movable nest is large and the resin is pulled on the molding surface of the movable nest.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plastic molding die 2 Transfer surface 3 Molding surface 4, 5 Movable insert 6, 7 Molding surface 8 Cavity 9, 10 Pressure control device 11 Resin (molded product) 12 Air gap 20 Plastic molding die 21 Transfer surface 22, Reference Signs List 23 molding surface 24 movable insert 25 molding surface 26 cavity 27 pressure control device 28 resin (molded product) 29 void

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kiyotaka Sawada 1-3-6 Nakamagome, Ota-ku, Tokyo Stock inside Ricoh Company (72) Inventor Hidenobu Kishi 1-3-6 Nakamagome, Ota-ku, Tokyo Stock In Ricoh Company (72) Inventor Katsuyuki Okubo 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Company (reference) 4F202 AH73 AH79 AM32 CA11 CB01 CK07 CK15 CK18 CK43 CN05

Claims (9)

[Claims] 1. A mold having at least one or more transfer surfaces and a movable nest forming surface movably provided as a cavity surface defining a cavity having a predetermined volume. Filling the heated molten resin to transfer the transfer surface to the molded product by the resin pressure of the molten resin, when cooling the resin below the softening temperature,
A method of manufacturing a plastic molded product, wherein at least one of the movable inserts is moved in a direction away from the resin to forcibly form a gap between the resin and a molding surface of the movable insert. Among the cavity surfaces other than the molding surface of the movable insert forming the gap, at least one or more cavity surfaces have an adhesion force with the resin by a predetermined adhesion strength improvement method, and the cavity has a gap. A method of manufacturing a plastic molded product, wherein the adhesive strength between a molding surface of the movable insert to be formed and the resin is made stronger. 2. A mold having at least one or more transfer surfaces and a movable nest forming surface movably provided as a cavity surface defining a cavity having a predetermined volume. Filling the heated molten resin to transfer the transfer surface to the molded product by the resin pressure of the molten resin, when cooling the resin below the softening temperature,
A method of manufacturing a plastic molded product, wherein at least one of the movable inserts is moved in a direction away from the resin to forcibly form a gap between the resin and a molding surface of the movable insert. Of the cavity surfaces other than the molding surface of the movable nest forming the gap, the cavity surface at a position facing the molding surface of the movable nest forming the gap is formed by a predetermined adhesion improving method. A method of manufacturing a plastic molded product, wherein the adhesive force with the resin is made stronger than the adhesive force between the molding surface of the movable insert forming the gap and the resin. 3. A cavity surface defining a cavity having a predetermined volume, the cavity surface having at least one or more transfer surfaces and a movable nest forming surface provided movably, and having a softening temperature within the cavity. Filled with heated molten resin,
Transferring the transfer surface to the molded product by the resin pressure of the molten resin, when cooling the resin to a softening temperature or less, by moving at least one or more of the movable inserts in a direction away from the resin, A plastic molding die forcibly forming a gap between the resin and the molding surface of the movable nest, wherein the cavity surface other than the molding surface of the movable nest forming the gap, At least one or more cavity surfaces are made to have a stronger adhesive force with the resin than an adhesive force between the molding surface of the movable insert forming the gap and the resin by a predetermined adhesive force improving method. A mold for plastic molding, characterized in that: 4. A cavity having at least one transfer surface and a movable nest forming surface movably provided as a cavity surface defining a cavity having a predetermined volume. Filled with heated molten resin,
Transferring the transfer surface to the molded product by the resin pressure of the molten resin, when cooling the resin to a softening temperature or less, by moving at least one or more of the movable inserts in a direction away from the resin, A plastic molding die forcibly forming a gap between the resin and the molding surface of the movable nest, wherein the cavity surface other than the molding surface of the movable nest forming the gap, A cavity surface at a position facing a molding surface of the movable insert forming the gap,
By a predetermined adhesion strength improving method, the adhesion strength with the resin,
A molding die for plastics, characterized in that it has stronger adhesion than a molding surface of the movable insert forming the gap and the resin. 5. The method according to claim 1, wherein the method for improving the adhesion is to improve the adhesion by forming minute irregularities on the cavity surface for improving the adhesion. A method for producing a plastic molded product according to any of the above, or a plastic molding die. 6. The method for improving the adhesion, wherein the temperature of the cavity surface for improving the adhesion is higher than the temperature of the molding surface of the movable nest forming the gap, thereby improving the adhesion. The method for producing a plastic molded product according to any one of claims 1 to 5, or a metal mold for plastic molding. 7. The method according to claim 1, wherein the molding surface of the movable insert forming the gap is subjected to a surface treatment for reducing the adhesive force with the resin to form another cavity surface defining the cavity. The plastic according to any one of claims 1 to 6, wherein the adhesive force with the resin is relatively stronger than the adhesive force of the molding surface of the movable insert with the resin. Molded product manufacturing method or plastic molding die. 8. The transfer surface, wherein the cavity surface having a stronger adhesive force with the resin than the adhesive force between the molding surface of the movable insert forming the gap and the resin is the transfer surface. The method for producing a plastic molded product according to any one of claims 1 to 7, or a mold for plastic molding. 9. The cavity surface, which has a stronger adhesive force with the resin than the adhesive surface between the molding surface of the movable insert forming the gap and the resin, transfers the plastic molded product to another part. The method for manufacturing a plastic molded product or the metal mold for plastic molding according to any one of claims 1 to 7, which is a reference surface for fixing.