JP4251749B2 - Manufacturing method of injection mold - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing an injection mold that includes a male mold and a female mold, and injects a resin into a cavity between both molds in a clamped state to mold a product.
[0002]
[Prior art]
Conventionally, in this type of injection mold, as shown in FIG. 4, a male mold a and a female mold b are respectively provided with product molding surfaces a1 and b1 facing the cavity, and product molding surfaces a1 and a sealing the cavity. The sealing surfaces a2 and b2 around b1 and the pressure receiving surfaces a4 and b4 that receive the clamping force are formed on the outside of the sealing surfaces a2 and b2 through the stepped surfaces a3 and b3. In the mold clamping completed state in which the sealing surfaces a2 and b2 of the male mold a and the female mold b are in contact with each other and the pressure receiving surfaces a4 and b4 of both molds a and b are in contact with each other, the sealing surfaces a2 and The b2 portion is elastically compressed and deformed so that a gap is not formed between the sealing surfaces a2 and b2 of both molds a and b even if resin is injected into the cavity at a high pressure (see Japanese Patent No. 2634548). ).
[0003]
By the way, when the resin is injected into the cavity, the female mold b receives the injection pressure and tries to widen in the direction perpendicular to the clamping direction. Therefore, conventionally, the pressure-receiving surfaces a4 and b4 of the male mold a and the female mold b are offset in the mold clamping direction with respect to the seal surfaces a2 and b2 of the molds so that the inner side of the step surface a3 of the male mold a. The step surface b3 of the female mold b is inserted into the step surface a3 of the male mold a and the step surface b3 of the female mold b is provided with a draft angle in the mold opening direction, and both the step surfaces a3 are clamped. , B3 is so-called cotter structure that is in surface contact so that the female die b can be prevented from being deformed so as to widen in the direction perpendicular to the clamping direction.
[0004]
However, this requires precise three-dimensional machining of the step surfaces a3 and b3 in addition to the product molding surfaces a1 and b1 and the seal surfaces a2 and b2, and it takes time to process the mold. The manufacturing cost of
[0005]
In this case, a female mold side lock member composed of a wedge-shaped block having a draft angle in the mold opening direction is attached to the outer surface of the female mold main body, and a female mold is attached to the outer surface of the male mold main body. A male lock member comprising a saddle-shaped block having an engagement surface with a draft angle in the mold opening direction capable of surface contact with the outer surface of the side lock member is attached, and the male mold side and the female mold side are clamped. It is also conceivable to restrict the female widening deformation by the wedge effect by the engagement of both lock members. According to this, it is not necessary to bring the step surface a3 of the male mold a and the step surface b3 of the female mold b into contact with each other, and the precision processing of the step surfaces a3 and b3 is not necessary, and the manufacturing cost of the mold is low. Become.
[0006]
[Problems to be solved by the invention]
When the female member is restricted from widening deformation with the lock member as described above, the outer surface of the female mold side lock member and the engagement surface of the male mold side lock member are kept in surface contact with the resin injected into the cavity. Thus, it is necessary to attach each lock member to each male body and female body in the required positional relationship.
[0007]
Therefore, the present invention provides a method for manufacturing an injection mold in which the male and female lock members can be accurately attached to the male and female mold bodies at the required positions. Is an issue.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is a method for manufacturing an injection mold comprising a male mold and a female mold, and injecting a resin into a cavity between both molds in a mold-clamped state to mold a product, A female mold side lock member composed of a wedge-shaped block having a draft angle in the mold opening direction is attached to the outer surface of the female mold body, and a female mold side lock member is attached to the outer surface of the male mold body. For mounting a male lock member consisting of a saddle-shaped block having an engagement surface with a draft angle in the mold opening direction that can be brought into surface contact with the outer surface of the mold, the male mold and female mold are stacked one on top of the other. In this state, once pressurize in the mold clamping direction, and after releasing the pressure, the male and female molds are put together in the male and female molds while the male mold and female mold are aligned. Each locking member is positioned so that the engagement surface of the male locking member comes into surface contact with the side surface. And by processing the attached part.
[0009]
Even if the male and female molds are stacked one on top of the other, the mating surfaces (seal surface and pressure-receiving surface) of the male mold and female mold will not be in close contact with the dead weight alone, but the clamping direction of the male mold and female mold When the pressure is applied to the mold, the mating surfaces of both molds are brought into close contact with each other, and the clamping state at the time of product molding is reproduced. After that, the mold clamping force is reduced by the injection pressure when the resin is injected into the cavity. Is reproduced. Thus, if the mounting portions of the respective lock members are processed as described above and the respective lock members are attached thereto, the outer surface of the female side lock member and the male side lock member can be formed even when the resin is injected into the cavity. The state in which the engagement surface is in surface contact is maintained, and the widening deformation of the female die due to the injection pressure is reliably regulated.
[0010]
In addition, when the mounting portion of the lock member is processed while the male mold and the female mold are pressed, the engagement surface of the male lock member comes into surface contact with the outer surface of the female lock member in the clamped state. When the clamping force is reduced by the injection pressure, both lock members are slightly displaced due to elastic deformation of the mold body, and a gap is formed between the outer surface of the female lock member and the engagement surface of the male lock member. As a result, the female mold is widened and deformed by the injection pressure by this gap. According to the present invention, such a problem does not occur.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an injection mold comprising a male mold 1 and a female mold 2. The female mold 2 is opened and closed in a horizontal direction with respect to the female mold 2 by a ram that is not shown. The product is molded by injecting molten resin into the cavity 3 between the two molds 1 and 2 while the movable mold is used and the male mold 1 is clamped to the female mold 2.
[0012]
The mold bodies 10 and 20 of the male mold 1 and the female mold 2 are respectively provided with product molding surfaces 11 and 21 facing the cavity 3 and seal surfaces 12 and 22 around the product molding surfaces 11 and 21 sealing the cavity 3. The pressure receiving surfaces 14 and 24 that receive the clamping force are formed on the outer sides of the seal surfaces 12 and 22 through the step surfaces 13 and 23, respectively. At the time of mold clamping, first, the sealing surfaces 12 and 22 of the male mold 1 and the female mold 2 are in contact with each other, and the pressure receiving surfaces 14 and 24 of the male mold 1 and the female mold 2 are in close contact with each other, The portions of the seal surfaces 12 and 22 of the molds 1 and 2 are elastically compressed and deformed so that no gap is formed between the seal surfaces 12 and 22 even when resin is injected into the cavity 3 at a high pressure.
[0013]
Further, as shown in FIG. 2 (A), the female mold side lock member 25 formed of a wedge-shaped block having a draft angle in the mold opening direction on the outer surface 25a is provided on the outer surface of the mold body 20 of the female mold 2. A plurality of (only one is shown in the figure) are attached with an interval in the extending direction of 24, and the outer surface of the mold body 10 of the male mold 1 is in surface contact with the outer surface 25 a of the female mold side lock member 25. A plurality of saddle-shaped blocks 15 having engaging surfaces 15a with a draft angle in the mold opening direction are attached in the extending direction of the pressure-receiving surface 14 (only one is shown in the figure), and a female die 2 can be controlled by the wedge effect due to the engagement of the lock members 15 and 25 on the male mold side and the female mold side to be deformed so as to expand in the direction orthogonal to the mold clamping direction upon receiving the injection pressure of the resin. ing.
[0014]
The male mold side lock member 15 and the female mold side lock member 25 are preliminarily slid and processed, and the lock members 15 and 25 are respectively attached to the outer surfaces of the mold main bodies 10 and 20 of the male mold 1 and the female mold 2. Bolts are attached to the mold main bodies 10 and 20 in a state of being fitted into the formed spot facings 10a and 20a. The mounting portions of the lock members 16 and 25, which are composed of the counterbore portions 10a and 20a and the screw holes 10b and 20b for bolts, are processed as follows. That is, as shown in FIG. 2B, the male mold 1 and the female mold 2 are pressed in the mold clamping direction by the external force F in a state where the other mold is overlaid on the other, and then the pressurization is released. In this state, the male mold 1 and the female mold 2 are kept in the mold-matched state, and the male mold 1 and the female mold 2 are in contact with the engagement surface 15a of the male lock member 15 and the female mold side. As shown in FIG. 2C, the counterbore portions 10a and 20a and the screw holes 10b and 20b are machined with an appropriate tool T 'in such a positional relationship that the outer surface 25a of the lock member 25 comes into surface contact. The reason why the male mold 1 and the female mold 2 are once pressurized in the mold clamping direction is that the pressure receiving surfaces 14 and 24 of the male mold 1 and the female mold 2 are brought into close contact with each other to reproduce the mold clamping state at the time of product molding. The external force F is preferably set so that the total value of the weight of the mold (male mold 1 in the illustrated example) and the external force F overlaid is equal to or greater than the clamping force at the time of product molding. When the pressurization is released after the pressurization, the mold clamping force reduced state due to the injection pressure when the resin is injected into the cavity 3 is reproduced. Thus, if the counterbore portions 10a and 20a and the screw holes 10b and 20b are processed as described above and the lock members 15 and 25 are attached to the die main bodies 10 and 20, the resin is injected into the cavity 3. However, the engagement surface 15a of the male mold side lock member 15 and the outer surface 25a of the female mold side lock member 25 are maintained in surface contact, and the widening deformation of the female mold 2 due to the injection pressure is reliably restricted.
[0015]
In this way, the wide deformation of the female mold 2 can be restricted by the engagement of the male and female lock members 15, 25, so the surface of the step surface 13 of the male mold 1 and the step surface 23 of the female mold 2. There is no need to regulate the widening deformation of the female mold 2 by contact. Therefore, in the present embodiment, the step surface 13 of the male mold 1 and the step surface 23 of the female mold 2 are formed so that a gap is formed between both the step surfaces 13 and 23. This eliminates the need for precision machining of the stepped surfaces 13, 23, shortens the mold machining time, and reduces the mold manufacturing cost.
[0016]
Further, in the present embodiment, the pressure receiving surfaces 14 and 24 of the respective types of the male mold 1 and the female mold 2 are offset in the mold opening direction with respect to the seal surfaces 12 and 22 of the respective molds, so that the step surface 23 of the female mold 2 is formed. The step surface 13 of the male mold 1 enters inside. According to this, there is no convex portion outside the sealing surface 12 of the male mold 1, and the corner portion between the sealing surface 12 and the product molding surface 11 is processed with a tool T such as a ball end mill as shown in FIG. Therefore, when the tool T is tilted outward with respect to the sealing surface 12, the tool holder Ta does not interfere with the mold body 10 even if the axial length of the tool T is short. Therefore, the sealing surface 12 and the product molding surface 11 can be efficiently processed with the tool T having a short axial length, and the processing time of the mold can be further shortened.
[0017]
【The invention's effect】
As is apparent from the above description, according to the present invention, the outer surface of the female-side lock member and the engaging surface of the male-side lock member are maintained in surface contact with the resin injected into the cavity. Thus, each lock member can be accurately attached in such a required positional relationship, and the widening deformation of the female die due to the injection pressure can be reliably regulated by the lock member, thereby improving the molding accuracy of the product.
[Brief description of the drawings]
FIG. 1 is a cut-away side view of an example of an injection mold manufactured by the method of the present invention. FIG. 2A is an enlarged cut-away side view of a main part of the mold, and FIG. FIG. 3C is a view showing the machining process of the mounting portion of the lock member. FIG. 3 is a view showing the male die processing state. FIG. 4 is a cut-away side view of a conventional injection mold.
DESCRIPTION OF SYMBOLS 1 Male type 2 Female type | mold 10,20 Type | mold main body 10a, 20a Counterbore part (attachment part of a lock member)
10b, 20b Screw hole (locking member mounting part)
15 Male mold side lock member 15a Engagement surface 25 Female mold side lock member 25a Outer surface of female mold side lock member

Claims (1)

A method for producing an injection mold comprising a male mold and a female mold, in which a product is molded by injecting resin into a cavity between both molds in a clamped state,
A female mold side lock member composed of a wedge-shaped block having a draft angle in the mold opening direction is attached to the outer surface of the female mold body, and a female mold side lock member is attached to the outer surface of the male mold body. A male side locking member comprising a hook-shaped block having an engagement surface with a draft angle in the mold opening direction capable of surface contact with the outer surface of
After the male mold and female mold are stacked on top of each other, pressurize in the mold clamping direction, and after releasing the pressure, the male mold and female mold remain in the combined state. In this state, the mounting portion of each lock member is processed on the main body in such a positional relationship that the engagement surface of the male lock member comes into surface contact with the outer surface of the female lock member.
A method for producing an injection mold characterized by the above.

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