JPH07171863A - Ejector pin of transfer mold - Google Patents

Abstract

PURPOSE:To provide an ejector pin capable of easily taking out a molded product from a mold while avoiding the generation of the surface flaw of the molded product. CONSTITUTION:In the ejector pins 7 for ejecting a molded product incorporated in transfer molds 1, 2, the leading ends of the ejector pins 7 thrust out into the cavity 8 of the mold are formed into a spherical surface 7b. By this constitution, the ejector pins are not bitten in the molded product 11 and the molded product 11 is easily separated from the ejector pins when taken out of the mold and the contours of the dents 11a formed to the surface of the molded product are not collapsed by the biting of the ejector pin and the generation of a surface flaw can be certainly avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an ejector pin incorporated in a transfer molding die.

[0002]

2. Description of the Related Art As is well known, a transfer molding die is provided with an ejector pin for taking out a molded product from the mold. FIG. 3 shows a general structure of a transfer molding die. In the figure, reference numerals 1 and 2 denote an upper die, a lower die, and 5 attached to a fixed side mounting plate 3 and a movable side mounting plate 4, respectively. Transfer pot, 5a is a transfer plunger, 6 is a runner, 7 is a mold cavity 8
The ejector pins are mounted on the mounting plates 3 and 4 so as to project toward, and 9 is an ejector plate, and 10 is an ejector ram.

In order to perform transfer molding with such a structure, molding resin is pressed from the transfer pot 5 through the runner 6 into the cavity 8 of the mold with the upper mold 1 and the lower mold closed, and molding is performed. Next, after the molded product is hardened in the mold, the mold is opened, and in this state, the ejector ram 10 is operated to project the ejector pin 7 into the cavity of the mold and push the molded product out of the cavity 8 of the mold. And release the molded product from the mold. .

[0004]

By the way, in the above-mentioned transfer molding die, in the conventional structure, the tip of the ejector pin 7 protruding into the cavity of the die is a flat surface 7a as shown in FIG. And its peripheral edge has an edge shape. Therefore, in the molding process, the tip of the ejector pin 7 slightly protruding into the cavity of the mold bites into the surface of the molded product 11, which causes the molded product 11 to eject when the ejector pin 7 projects after molding. It is difficult for the molded product 11 to be detached from the mold, and when the molded product 11 is pulled out from the ejector pin 7 and taken out of the mold, the contour of the concave recess 11a formed on the surface of the molded product 11 due to the bite and bite of the ejector pin It collapses and deforms, resulting in surface defects that impair the appearance of the product.

The present invention has been made in view of the above points, and an object of the present invention is to solve the above-mentioned problems, to avoid the occurrence of surface defects on a molded product, and to easily remove the molded product from a mold. An object of the present invention is to provide an ejector pin of a transfer molding die that can be performed.

[0006]

According to the present invention, the above object is achieved by forming the tip of the ejector pin projecting into the cavity of the mold into a spherical surface.

[0007]

As described above, by making the tip of the ejector pin a spherical surface, the ejector pin does not bite or bite into the molded product, so it can be easily separated from the ejector pin when the molded product is taken out from the mold. In addition, even if the posture of the molded product is inclined at the time of detaching the molded product from the ejector pin, it is possible to avoid the occurrence of surface defects such as collapse of the contour of the recess formed on the surface of the molded product due to contact with the ejector pin.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The same members as those in FIG. 2 are designated by the same reference numerals. That is, in the embodiment of FIG. 1, regarding the ejector pin 7 incorporated in the transfer molding die, in particular, the tip of the pin protruding into the cavity 8 of the dies 1 and 2 has a smooth spherical surface 7b as shown in the figure. Is finished in advance so as to exhibit the above condition, and in the molding process, the ejector pin 7 is retracted and waits at a position where only the tip portion of the ejector pin 7 is slightly exposed to the inside of the cavity 8.

After the molding, the upper mold 1 and the lower mold 2 are opened, and when the ejector pin 7 is projected and operated into the cavity of the mold in this state, the molded product 11 is released from the cavity 8 and pushed out. In this case, since the tip of the ejector pin 7 has the spherical surface 7b, it does not bite into the surface of the molded product 11, and therefore the molded product 11 can be easily separated from the ejector pin 7. Moreover, when the molded product 11 is detached from the ejector pin 7, even if the posture of the molded product is inclined, it does not interfere with the ejector pin. There is no danger of it occurring.

[0010]

As described above, according to the structure of the present invention, the ejector pin protruding into the cavity of the mold has a spherical tip, so that the following effects can be obtained. (1) The ejector pin does not bite into the molded product, and when the molded product is taken out of the mold after molding, the molded product can be easily separated from the ejector pin, improving the workability of removing the molded product. Can be achieved.

(2) Even if the posture of the molded product is inclined when the molded product is ejected by the ejector pin, the contour of the dent formed on the surface of the molded product at the time of molding due to contact with the ejector pin collapses the surface defect. The occurrence can be reliably avoided.

[Brief description of drawings]

FIG. 1 is a diagram showing a mold and a molded product using an ejector pin according to an embodiment of the present invention.

FIG. 2 is a diagram showing a mold and a molded product using a conventional ejector pin.

FIG. 3 is a detailed assembly configuration diagram of a transfer molding die to which the present invention is applied.

[Explanation of symbols]

 1 Upper mold 2 Lower mold 7 Ejector pin 7b Spherical surface 8 Cavity 11 Molded product 11a Cavity

Claims (1)

[Claims] 1. An ejector pin for ejecting a molded product incorporated in a transfer molding die, wherein the tip of the ejector pin protruding into the cavity of the die is a spherical surface. Ejector pin.