JPS6054847B2 - injection mold - Google Patents

Description

[Detailed description of the invention] (b) Industrial application field The present invention relates to a synthetic resin injection mold.

(Explanation) Conventional technology The next step is to remove molds from synthetic resin injection molded products without causing "galling" (scratches that occur when the surface of the mold and the molded product move relative to each other in the release direction) on the outer surface. There is something like.

That is, as proposed in Japanese Patent Application Laid-Open No. 49-31758, only the core is pulled out first while the molded product remains in the female mold, and after the molded product has shrunk and its outer surface has separated from the female mold. The molded product is removed from the female mold. According to this method, there is no need to split the female mold, so no parting line is generated on the outer surface of the molded product. However, in the device proposed in the above publication, a special member is used to press the molded product against the female mold while the core is being extracted, and after the core has been extracted, the molded product is pulled out from the female mold using that member. Therefore, it is necessary to provide the molded product with an undercut portion for engaging the member, and there is a problem that this undercut portion impairs the aesthetic appearance when molded from a transparent material. ←→ Problems to be Solved by the Invention The present invention provides a structure in which the molded product is removed from the female mold after the core has been extracted, and does not require the formation of an undercut portion to take out the molded product from the female mold. With the goal.

(: Means for Solving the Problems In the present invention, both the core and the female mold belong to the movable block.

The female mold is placed between the core base and the stationary block, and is biased with a spring so that it separates from the core base except when the mold is clamped. The female cavity forms the peripheral wall of the molded product between the core and the cavity, which is open toward the stationary block and has a shoulder that forms the end surface of the molded product toward the core base. . Further, the movable block is provided with an ejector pin that projects the molded product from the female mold after the core base and the female mold are separated and the core is removed from the molded product. (e) When the working core is removed from the molded article, the shoulder of the cavity holds the molded article in the female mold.

The molded product is removed from the female mold by ejecting the molded product toward the stationary block using an ejector pin. Therefore, there is no need to provide any kind of engagement undercut in the molded product. (v) In the drawings of the embodiment, 1 is a fixed side block and 2 is a movable side block.

The fixed side block 1 includes a fixed side template 3 and an anguilla pin 5 protruding from the spool bush male plate 3 attached to the template 3. The movable side block 2 is a fixed side template 3
It has a movable base 6 that moves forward and backward with respect to the movable base 6, a core base 7 fixed to the movable base 6, a female die 8 supported so as to be able to be separated from the core base 7, and a slide core 9 supported on the front surface of the female die 8. A core 10 is fixed to a core base 7, and is inserted into a hole-shaped cavity 11 formed in a female mold 8, to form a molding cavity in a portion that will become a cylindrical peripheral wall in a molded product.

The cavity 11 is open toward the stationary block 1, and has a shoulder 17 forming an end surface of the molded product toward the core base 7. The core 10 has a knob-like protrusion 12 at the top, and a molding gap is also formed between this and the slide core 9. Note that although the core 10 is tapered, the cavity 11 is not tapered. 13 is an ejector pin that passes through the core base 7 and the core 10, and 14 is an ejector plate to which the ejector pin 13 is attached.

A guide pin 15 passing through the core base 7 and the female mold 8 is attached to the ejector plate 14 . The female die 8 slides along the guide pin 15. The core base 7 is always biased away from the core base 7 by a compression coil spring 16 inserted between the core base 7 and the core base 7. The above mold operates as follows.

Figure 1 shows the state when the mold is closed, and the spool bush 4 is closed. A molded product A has just been injection molded.
When the mold is opened, the slide core 9 is opened to the left and right by the anguilla pin 5 as shown in FIG. Move forward from the situation. Due to the presence of the shoulder 17, the molded part A remains in the cavity 11 and the core 10 comes out of the molded part A. When the core 10 is removed, the molded product A shrinks freely. The shrinkage rate is about ABS resin? It is made of polypropylene, and the diameter of the cavity is 1.
When it is 00Tn1n, if it is oil S resin, it is about 0.5? ,
If polypropylene is used, the diameter of molded product A will be smaller by about 1.5 Twt1. This creates a void between the outer surface of molded product A and the inner circumferential surface of cavity 11, so if the size of molded product A and the type of resin are selected so that the size of the void becomes an appropriate value, Later, when the ejector plate was pushed out as shown in Figure 3, the outer surface was "grabbed".
The molded product A is molded into the hole-shaped cavity 11 without any
It can be protruded from the axial direction. (G) Effects of the Invention In the present invention, the shoulder provided in the cavity of the female mold is used as a means for holding the molded product when the core is removed, and the molded product is removed from the female mold using a common ejector pin. There is no need to provide an undercut connection between the molded product and the member for removing it from the female mold.

Therefore, even when molded products are made of transparent resin, undercuts have never been noticeable. Furthermore, in the configuration of the present invention, it is also possible to arrange a slide core between the female mold and the stationary block, and it is possible to provide variety in the shape of the molded product.

[Brief explanation of the drawing]

The figure shows an embodiment of the present invention.
The figure is a cross-sectional view when the mold is opened, and FIG. 3 is a cross-sectional view when the molded product is ejected. 1... Fixed side block, 2... Movable side block, 7... Core base, 10...
・Core, 8...Female type, 16...Spring,
11...Cavity, 17...Shoulder part,
13...Ejiectapin.

Claims (1)

[Scope of Claims] 1. An injection mold consisting of a fixed side block and a movable side block, wherein the movable side block includes the following components. (a) A core base with a fixed core having a taper. (b) A female mold located between the core base and the stationary block and biased by a spring so as to separate from the core base except when the mold is clamped. (c) It is provided in the front female die and forms the peripheral wall of the molded product in cooperation with the core, and is open when facing the fixed side block and forms the end face of the molded product when facing the core base. A cavity having a shoulder portion. (d) An ejector pin that ejects the molded product from the female mold after the core base and female mold are separated and the core is removed from the molded product when the mold is opened.