JPH0577286A - Ejecting method for resin molding - Google Patents

Abstract

PURPOSE:To prevent a molded item from catching on a mold. CONSTITUTION:The forward end of each first eject pin 4 contacts the end of an opening of a cap-shaped molded item 1, while the forward end of each second eject pin 21 contacts the inside bottom surface of the item 1. The second eject pins 21 passing slidably through a molding plate 3 including a core and an eject plate 6 facing the rear surface of the plate 3 are urged against the plate 3 by springs 22 and steps 21a, 21b are formed on the surface of the pin 21 in the length direction thereof in such a manner that the diameter of the pin increases stepwise toward the rear end thereof. When the first step 21a contacts the plate 3 during the ejecting operation of the plate 6, the pin 21 is rendered standstill. When the ejecting operation of the plate 6 has been completed, the forward end of each of the pins 4 is projected from the plate 3 equally or farther relative to the end of each of the pin 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molding method, and more particularly, when forming a cap-shaped molded product by resin molding, it is necessary to bring an eject pin into contact with the opening end face and inner bottom face of the molded product. Regarding eject method.

[0002]

2. Description of the Related Art FIG. 3 is a plan view (a) and a side view (b) of a resin molded product having a cap shape. In a molded product 1 in which it is not desired to make an eject mark on the outer surface for reasons of use and appearance, Generally, the mold die is designed so that the contact marks 2 of the eject pins are located at four locations on the corner portion of the peripheral end surface and a plurality of locations on the inner bottom surface (four locations in the figure).

FIG. 4 is a side view for explaining an ejecting mechanism of a conventional resin molding die, 3 is a template in which a molding core projects in the center, and 4 is a tip end surface of a peripheral end surface of a molded article 1 abutting against the corner surface. (Protruding) eject pin 5, 5 is an eject pin whose tip surface abuts (protrudes) the inner bottom surface of the molded product 1, 6 is an eject plate, 7 is a holder for fixing the eject pin 5 to the eject plate 6, and 8 is the eject plate 6 Coil spring for pushing back, 9 is holder
A fixing member to which the template 3 is fixed via 10, a coil spring 11 that pushes back the eject plate 6 toward the fixing member 9,
A shaft 12 is mounted on the eject plate 6 and fitted with the coil spring 11.

FIG. 5 is an explanatory view of the eject of the resin mold shown in FIG. 3. By applying a pressing force F by a hydraulic cylinder or the like to the eject plate 6, the eject plate 6 advances toward the mold plate 3. The ordinary molded product 1 is ejected from the template 3 by the eject pins 4 and 5 that vigorously protrude.

However, the eject pin 4 and the eject pin 5 have the same stroke, and the eject pin 4
Is shorter than the eject pin 5, so that it may be caught on the eject pin 5 as in a molded product 1'shown by a chain line in the figure.

[0006]

In the conventional method, there is a problem that the molded product 1'hooked on the eject pin 5 is crushed when the mold is clamped, and the mold is damaged thereby.

[0007]

According to FIG. 1, which shows the main part of a mold according to the method of the present invention, the tip end surface of the first eject pin 4 is formed on the opening end surface of the cap-shaped molded article 1. And the second eject pin 21 on the inner bottom surface of the molded product 1
Of the resin molding die with which the front end surface of the mold abuts, the second ejector slidably penetrating the mold plate 3 having the core of the molded product 1 on the front surface and the eject plate 6 facing the back surface of the mold plate 3. The pin 21 is provided with stepped portions 21a and 21b that become thicker in the first and second steps from the middle portion in the length direction toward the rear end portion. The eject plate 6 having the rear end portion of the first eject pin 4 fixed thereto is provided with a stepped hole with which the second step portion 21b of the second eject pin 21 abuts. Between the fixing member 9 and the eject plate 6 to which three template plates are fixed,
A spring that biases the second eject pin 21 toward the template 3.
22 is provided. The first step portion 21a of the second eject pin 21 located between the template 3 and the eject plate 6 facing each other.
Comes into contact with the template 3 during the eject operation of the eject plate 6, and the eject operation of the second eject pin 21 is stopped by the abutment 21a of the first step portion, and the eject operation of the eject plate 6 is completed. At this point, the tip surface of the first eject pin 4 projects from the template 3 as much as or more than the tip surface of the second eject pin 21.

[0008]

According to the above means, the second eject pin 21, which is longer than the first eject pin 4 because it penetrates the core portion of the template 3, is stopped during the eject operation, and when the eject operation is completed. Eject pin 4 with first tip
Be careful not to protrude from the tip surface of. Therefore, molded product 1
Can reliably be released from the mold by the ejecting operation of the mold, and the conventional problem that the molded product 1 may be crushed during mold clamping is eliminated.

[0009]

1 is a side sectional view showing the structure of the main part of a mold according to an embodiment of the method of the present invention, and FIG. 2 is an explanatory view of the eject of the mold shown in FIG.

In FIG. 1, 3 is a template from which a molding core projects in the center, 4 is an eject pin whose tip end surface abuts (protrudes) on the peripheral end surface corner of the molded product 1, 6 is an eject plate, and 7 is an eject plate. 6 eject pin 5
Is a compression coil spring for pushing back the eject plate 6, 9 is a fixing member to which the template 3 is fixed via the holder 10, 11 is a coil spring for pushing the eject plate 6 toward the fixing member 9, and 12 is Shaft to be mounted on the eject plate 6 and to which the coil spring 11 is fitted, 21 is a molded product 1
The eject pin whose tip end surface abuts (protrudes) on the inner bottom surface of the device, and 22 is a compression coil spring inserted between the eject plate 6 and the fixing member 9.

The eject pin 21 becomes thicker in two steps from the middle part toward the end part fitted to the eject plate, and the coil spring 22 is provided in the recess provided at the right end of the eject pin 21 and the fixing member 9. Fit in the recess.

The first step portion 21a provided in the central portion of the eject pin 21 is exposed between the template 3 and the eject holder, and the second step portion 21b provided in the fixing member 9 is provided in the eject plate 6 It fits into the stepped hole 6a.

In FIG. 2, when a pressing force F is applied to the eject plate 6 by a hydraulic cylinder or the like and the eject plate 6 is advanced (ejection operation) toward the mold plate 3, the eject pins 4 and 21 are moved from the mold plate 3. As a result, the molded product 1 is projected from the template 3.

However, while the eject pin 4 projects by the same stroke as the eject plate 6, the eject pin 21 does not move during the operation of the eject plate 6.
The forward movement is stopped in the state where the end face of a is in contact with the back surface of the template 3, and the coil spring 22 absorbs the subsequent forward movement of the eject plate 6. Then, when the eject operation (forward movement) of the eject plate 6 is completed, the eject pin
The leading end surface of 21 is stopped while it is retracted from the leading end surface of the eject plate 6.

Therefore, according to the method of the present invention, the eject pin
The molded product 1 using the mold provided with 21 and the like is separated from the mold plate 3 without the whole number of the molded product 1 being caught by the eject pins 4.

[0016]

As described above, according to the method of the present invention, the molded product can be reliably released from the mold by the ejecting operation of the mold, and the conventional problem that the molded product may be crushed when the mold is clamped is solved. There is a canceled effect.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a configuration of a main part of a mold according to an embodiment of the method of the present invention.

FIG. 2 is an ejection explanatory diagram of the mold shown in FIG.

FIG. 3 is an explanatory diagram of a resin molded product having a cap shape.

FIG. 4 is an explanatory diagram of an eject mechanism of a conventional resin mold die.

FIG. 5 is an ejection explanatory view of the resin mold die shown in FIG.

[Explanation of symbols]

 1 is a resin molded product 3 is a template provided with a core 4 is the first eject pin 21 is the second eject pin 21a is the second eject pin the first step 21b is the second eject The second stepped portion 6 of the pin is an eject plate 9 is a fixing member to which a core forming template is fixed, and 22 is a coil spring for urging the second eject pin.

Claims (1)

[Claims] 1. A molded article (1) in the shape of a cap, wherein the tip end surface of a first eject pin (4) contacts the open end surface of the molded article (1).
In the resin mold die in which the tip surface of the second eject pin (21) contacts the inner bottom surface of (1), the molded product is formed on the surface.
The second eject pin (21) slidably penetrating the template (3) provided with the core of (1) and the eject plate (6) facing the back surface of the template (3) , A step portion (2 which becomes thicker in the first and second steps from the middle portion in the length direction toward the rear end portion)
1a, 21b) and the eject plate (6) to which the rear end of the first eject pin (4) is fixed has the second step (21b) of the second eject pin (21). The second eject pin is provided between the fixing member (9) to which the template (3) is fixed and the eject plate (6) by providing a stepped hole for abutting.
A spring (22) for urging (21) toward the template (3) is provided, and the second eject pin (2) located between the template (3) and the eject plate (6) is opposed. 21) first step (21a)
Comes into contact with the template (3) during the ejecting operation of the eject plate (6), and the ejecting operation of the second eject pin (21) is caused by the contact (21a) of the first stepped portion. When the ejecting operation of the eject plate (6) is completed, the tip surface of the first eject pin (4) is equal to or more than the tip surface of the second eject pin (21). A method for ejecting a resin molded product, characterized in that it is projected from the template (3).