JPS61137718A - Hot-runner mold - Google Patents

Abstract

PURPOSE:To contrive to improve the separating property of a molded part from a hot runner at mold release by a method wherein a bar heater or movable inner wall part is pivoted by a driving device attached on a cavity side part. CONSTITUTION:Firstauly, the tip 9a of a bar heater 9 is off-centered to a gate part 7a. Secondly, when the mold release of a molded part is intended, after the molambdaded part solidififO9a in order to be able to completely cut off the molded part from the molten resin in a hot runner 6 by shearing force produced by the plugging-up action of the tip. Thus, the runner 6 and the molded part are surely cut off, even when the gate part 7a is not in the state fully cooled and solidified, resulting in preventing the threading between the runner and the molded part from developing and the folloeing molding action from obstructing.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" This invention is based on 19. The hot runner gold ff1 has good separation between the hot runner tip gate part and the molded product in the mold cylinder and does not cause threads to be drawn to each other.

``Prior Art'' Conventionally, in injection molds, there is a hot runner mold in which the 5IC runner section is heated so that the runner is not cut out due to material economy. There are two known types: one with a TV structure that is equipped with an internal heater to heat the runner part to prevent solidification, and the other with a structure in which the runner part is heated from the outside.

"Problems to be Solved by the Invention" Unlike general molding molds, the conventional hot runner mold mentioned above does not allow the middle part of the hot runner to remain intact even after one hour of cooling during molding. The tip gate of this hot runner is also maintained at a relatively high temperature, so after cooling, the movable mold is moved and the tip gate of the hot runner is moved when the mold parting lie is opened. The separation of the resin between the molded part and the gate part of the molded product is poor, and threads may be drawn between them. If the thread is pulled in this way, even if the molded product is released with an ejector rod, the molded product will adhere to the hot runner through the thread at the end of the hot runner, [stopping the next molding operation, or damaging the resulting molded product]. The product requires additional processing operations such as post-processing, which significantly reduces production efficiency.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a hot runner mold that can easily separate a molded article from a hot runner during mold release.

"Means for Solving the Problems" The hot runner mold according to the present invention has a rod-shaped heater whose tip is located near the cavity side exit in the runner section of the mold, along the center line of the cavity side exit of the runner section. The rod-shaped heater is configured to be eccentric relative to the surrounding fixed member such as a cavity plate (first invention), or the cylindrical inner wall portion including the cavity side outlet of the runner portion The movable inner wall can be rotated separately with respect to peripheral fixed members such as a surrounding cavity plate, and the cavity side outlet of this movable inner wall can be arranged in the same circular shape at a position eccentric to the center of rotation of the inner wall. According to a second aspect of the present invention, the rod-shaped heater or the two movable inner parts are rotated by a drive device attached to the identification side mold.

"Function" According to the above structure, if the drive device is started in synchronization with the movement of the movable mold and the rod-shaped heater or the movable inner wall is rotated, the gate part at the tip of the hot runner and the molded product can be connected. Even if the gate part at the tip of the hot runner is not sufficiently cooled and solidified, the hot runner and molded product will be reliably separated and will not pull strings against each other.
Become. As a result, there is no hindrance to the next molding operation, and extra processing operations such as post-processing of the molded product are unnecessary, making it possible to improve productivity.

Hereinafter, this invention will be explained in more detail with reference to Examples.

First, the first invention will be explained.

``Example'' Figures 1(a), (b), and (o) show an example of the first invention, and the reference numeral 1 in the figures indicates a stationary mold. A gap 5 is formed between the l cavity plate 2 and the i nifold 3 by a spacing member 4. Inside the cavity plate 2 is a hot runner 6 that opens toward the cavity.

It is formed. The hot runner 6 is constituted by a cylindrical runner pusher layered and fixed within the cavity plate 2. Konou/Na・
The tip C gate @) 7& of the putushinia has a reduced diameter and opens so as to protrude slightly outward (toward the movable mold side) from above the parting line PL. This hot runner 61C is a melting fat channel 8 provided in the manifold 3.
are connected to each other, and a rod-shaped heater 9 is attached inside thereof so as to be freely rotatable in the circumferential direction. The rotation center of this rod-shaped heater 9 is offset from the central axis passing through the gate portion 7 & of the runner e-put senior, and is rotated by a motor 11 fixed to the side of the stationary mold 10 via a transmission belt 10. It is now possible to do so. The tip end 9& of this array heater 9 is tapered in diameter, and depending on its rotational position 1, it closes the gate portion 7&.

However, the above! According to Nanari, when injecting molten resin,
As shown in FIG. 1(b), the tip 9& of the four-shaped heater 9 is shifted from the gate portion 7& (if),
When releasing the molded product after solidification, the motor IIK rotates the four heaters 9 and closes the gate part 7& with the tip 9&, as shown in Fig. 1(c), and the shear force generated at that time causes the molded product to separate. The molten resin in the hot runner 6 can be completely cut in one place.

Next, an example of the second invention will be shown.

"Embodiment" Figure 2 (b) shows an embodiment of the second invention, and parts common to Figure 1 (a), (b), and (c) are given the same reference numerals. In the present invention, the runner bush (cylindrical inner wall portion) 20 is rotatably provided via a bearing 21 with respect to the cavity grate 2, which is one generatrices member. There is.

The gate portion 20& of this runner bush 20 opens to WL at an eccentric distance with respect to the rotation center -IC of this runner bluff 1200. And these 92 runner bushes 20 are powered by motor 11! ! 2i, the circular part is provided with a cylindrical heater 22 as in the conventional case. According to the above configuration, the motor 11
When the movable runner bushing 20 is rotated, the gate part 0a itself rotates around a circumference of a predetermined size, and as a result, the relationship between the molded product and the @Aichi fat inside the hot runner 6 is An opening shear force will be generated, resulting in a complete cut.

"Effects of the Invention" As explained above, according to the present invention, if the motor (drive device) is started in synchronization with the mold release and the rod-shaped heater or runner bush (excitable inner wall booklet) is rotated, the hot Even if an R break force occurs between the resin at the gate at the tip of the runner and the molded product, and the gate at the tip of the hot runner is not sufficiently cooled, the hot runner and the molded product are securely connected. As a result, there is no hindrance to the next molding operation, and there is no need for extra processing operations such as post-processing of the molded product, improving productivity. I can do it.

[Brief explanation of the drawing]

10(a), (b), and (c) show an embodiment of the first invention, (&) is a cutaway f-1('b)Cc) of the main part, respectively, is a front view of the gate part, Figures 2c to (b) show one implementation row of the second invention (Xu is a side sectional view of the main part, (b)
) is a front view of the gate part. 1... Fixed side mold, 2... Cavity plate, 6... Hot runner-17.1.
・20a...Gate part (cavity side exit of runner part), 9...Rod-shaped heater, 11...
...Motor (6jj device f>, 20...Runner bush (movable inner wall part). Second - Mogo

Claims (2)

[Claims] (1) In a hot runner mold configured to constantly heat the runner section from the sprue of the stationary mold to the cavity entrance, a rod-shaped heater whose tip is located around the cavity entrance in the runner section. is eccentric with respect to the center line of the outlet of the cavity side of the runner part, and the rod-shaped heater is configured to be rotatable relative to a peripheral fixed member such as a surrounding cavity plate, and the rod-shaped heater is attached to the fixed side mold. A hot runner mold characterized in that it is configured to be rotated by an attached drive device. (2) In a hot runner mold that is configured to heat a runner section from the sprue of the stationary mold to the cavity entrance, the cylindrical inner wall section including the cavity side exit of the runner section is connected to the surrounding cavity.・The movable inner wall is configured to be rotatable separately from a peripheral fixing member such as a plate, and the cavity side outlet of the movable inner wall is formed at a position eccentric to the rotation center of the cylindrical movable inner wall. 1. A hot runner mold, characterized in that said part is configured to be rotated by a drive device attached to said stationary mold.