JPS5889338A - Cutting device for gate of resin molded product - Google Patents

Abstract

PURPOSE:To enable to obtain a smooth cut surface by means of a retainer force of a mold, by a method wherein a cavity between a fixed and a moving mold is coupled to a runner through the medium of a rotatable gates, and the gates are cut by turning a gate member after injection of resin for filling and before releasing the molds. CONSTITUTION:Recessed gates 6 are formed in an inner end surface 3a of a gate member radially from the center thereof, and a gate port 6a forms a terminal in a spot positioned eccentrically from the axis of the gate member 3 and on the inner end surface. After resin, injected into a cavity 4 after passage through the gates from a runner 5, is molded and cured, the gates, with the gate member 3 turned in a direction of an arrow mark A, is forcibly turned, thereby allowing smooth cutting of the gates at an interface between a fixed mold 1 and a moving mold 2 to separate it from a molded product in the cavity 4. The mold 2 is then detached from the mold 1 to remove the molded product from the cavity 4, and simultaneously, unnecessary resin in the runner 5 and the gate 6 is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for producing a molded article in a mold by injection molding of thermoplastic am. This is related to a device for cutting gates.

As a conventional gate cutting device, for example, Tokuko Sho 5g-1
As shown in No. 4467, it has been proposed that the boundary between the product and the gate runner is cut by sliding of the gate core. However, in this known gate cutting device, the gate core is slid and cut after separating the fixed mold and the movable mold, and the entire periphery of the product and the gate runner are fixed. Instead, the product and/or the gate holder may move slightly during round cutting while attached to the movable mold, making it impossible to obtain the desired smooth cut surface. First, since the gate core is slid for cutting, extra movement space is required in the sliding direction of the gate core, which increases the size of the device or requires extra hem space.

The present invention was made with attention to the above-mentioned problems, and its purpose is to be able to cut the gate while the molded product is fixed in the resin molding die, and to reduce the need for personnel searching for the equipment. The purpose of the present invention is to provide a gate cutting device that does not require additional installation space.

That is, according to the gate cutting device for resin molded products according to the present invention, the cavity formed between the fixed mold and the movable mold is communicated with the runner via the rotatable gate portion,
The gate opening of the gate member is formed eccentrically from the rotation axis, and the gate member is rotated after injection and filling of the resin into the cavity and before separating the fixed mold and the movable mold. Naru no deru.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

First, in the overlap gate according to the tJil embodiment of the present invention shown in FIG. A shaped gate member 8 is rotatably inserted, and its inner end surface 8
A is completely formed with the same WJ in the horizontal direction as the inner end surface of the fixed mold l.

A cavity 4 and a runner 6 are formed separately on the movable mold side at the interface between the fixed metal all and the movable metal wg,
The inner end surface 8& of the gate member 8 faces between the cavity 4 and the runner 6. A concave gate 6 is formed radially from the center on the inner end surface of the gate member 8, and the gate opening 6 is eccentric from the axis of the dart member 8 and terminates at a position on the inner surface. This gate 6 overlaps between the adjacent end portions of the cavity 4 and the runner 6 from the fixed mold side, and communicates them during molding. That is, the center portion of the gate 6 communicates with the inner end of the runner 6 in the vertical direction, and the gate opening 6& communicates with the cavity 4 in the vertical direction.

# When molding a resin, when a molten thermoplastic resin is injected from a known injection molding machine into the sprue of a mold, this resin flows into the runner 51! - Through) Furthermore, it passes through the gate 6 of the gate member 8 and enters the cavity 4 from the gutro 6a, where it is molded and solidified into a predetermined shape. After that, when the goo 1 member @ is rotated in the direction of the arrow in FIG. The movable mold 2 is cut smoothly at the interface and separated from the molded product on the west side of the cavity 4. Next, the movable mold 3 is moved and separated from the fixed mold 1, and molded from within the cavity 4 by a known method. At the same time as taking out the product, unnecessary fat inside the runner 6 and gate 6 is removed. Thereafter, the gate member 3 is again rotated in the opposite direction to the arrow M, the gate 6 is set to the position indicated by the solid line, and the movable mold 2t and the fixed mold 1 are closed to prepare for the next injection of resin. .

FIG. 2 shows the case of a side gate according to a third embodiment of the present invention, and in this second embodiment, the gate 6 of the goo 1 member 3 extends radially from its center to reach the curved surface. This curved portion is different from the first embodiment in that it communicates with the goo 1 opening 6a and the cavity 4 from the lateral direction, and the other configurations are substantially the same as the lit embodiment. It comes out.

Even in the case of this Embodiment, the resin pipe cavity 4
When the gate member S is rotated in the direction of the - arrow mark, the resin in the cavity, the gate 6, and the O communication portion is cut by the curved surface of the dart member 8, and the resin in the gate 6 is It comes to the position shown by the dotted line in Figure 2 (lI).After that, 1 movable metal W! is separated from the fixed metal W1,
Taking out the molded product from the cavity 4 by a known method is the same as in the first embodiment.

FIG. 1 shows the case of a bin gate according to an eighth embodiment of the present invention, in which the entire end surface of the gate member 8 cooperates with the fixed metal mold W1 and the movable mold 2 to define a cavity 4. are doing. Further, a runner 6 is formed by extending the inside of the dart member 8 in the longitudinal direction, and the bottle gate 6 is connected to the runner 6.
The dart member 8 is linearly continuous with the dart member 8 and is deflected from the axis of the dart member 8 to extend to its end surface. The other configurations are substantially the same as in the first embodiment.

In the case of this eighth embodiment as well, the resin was
After injecting and solidifying the gate member 8 in FIG.
), the goo F06a rotates from the position shown by the solid line to the position shown by the dotted line, so that the resin in the communication area between the cavity 4 and the gate 6 forms a smooth surface on the end surface 8a of the gate member 8. will be cut off as Thereafter, the movable metal Wi2 is separated from the fixed mold 1 and the molded product is ejected from the cavity 4 by a known method, as in the first embodiment.

As described above, in the gate cutting device for resin molded products according to the present invention, after the resin is injected and filled into the cavity and before the fixed mold and the movable mold are separated, the gate cutter disposed in the mold is By rotating the part, the resin of the gate can be cut so that the molded part is firmly held by the mold and the molded part and/or the resin does not move when cutting. The desired and reliable cut is made without any problems. In addition, when cutting darts, the gate member 8 only needs to be rotated nine times, and there is no need for supplementary motion as in the conventional method, so there is no need to increase the size of the mold itself or require extra installation space. .

[Brief explanation of the drawing]

1 to 8 show dart cutting 11M according to the first to eighth embodiments of the present invention, respectively, and <a> in each figure
is the main part II! Cross-sectional view ((9) is a plan cross-sectional view thereof. 1...Fixed mold 2...-Movable mold 8...Gate Member 4...Cavity 5...Runner 6...Gate Patent Applicant: Yoshida Kogyo Co., Ltd. Daisanhito, Patent Attorney - Color Confucianism

Claims (1)

[Claims] (1) Nine cavities formed between the fixed mold and the movable mold are communicated with the runner via a rotatable gate member, and the gate opening of the wrinkle gate member is connected to the runner from the rotation. A resin molded product, which is formed eccentrically and is configured such that the gate member is rotated after the cavity is injected and filled with a tree layer and before the fixed mold and the movable mold are separated. Gate cutting device. (2) The cavity and the runner are formed separately at the interface between the fixed mold and the movable mold, and the gate member is formed such that its axis is perpendicular to the interface between the two molds. 2. A gate cutting device for a resin molded product according to claim 1, wherein the gate formed on the end face of the gate member partially overlaps the cough cavity and the runner. (8) The cavity and the runner are separately formed at the interface between the fixed mold and the movable mold, and the goo 1 member is made such that its axis is perpendicular to the interface between the two molds. Nine gates are formed on the end face of the gate member and extend radially from the center to the circumferential edge, communicating with the runner at the center and communicating with the cavity at the circumferential edge. A gate cutting device for resin molded products according to claim 1, characterized in that: (4) An end surface of the gate member defines the cavity, the runner is formed longitudinally inside the gate member, and the gauge is continuous with the runner and along the axis of the gate member. A gate cutting device for a resin molded product according to claim 1, characterized in that the gate is formed to extend from the center in the direction I.