JPH04251720A - Polymer material injection mold - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection mold used for manufacturing injection molded articles of polymeric materials.

0002

[Prior Art] Conventionally, in the injection molding process, a single cavity or a plurality of continuously connected cavities are formed inside the mold, and a liquid at a desired temperature is circulated through the cavities to maintain the quality of the molded product. has been controlled.

0003

[Problems to be Solved by the Invention] However, in the conventional injection molding process, as shown in FIGS. Polymer material is filled from the polymer material filling inlet (hereinafter referred to as gate) of , and the polymer material flow surface tips spread concentrically around each gate tip as shown in 3a and 3b, and are finally injected. When filling the molded product shape, a boundary line pattern (hereinafter referred to as a weld line) was generated at the part 4 where the resin flows, which had cooled and started to show a solidification phenomenon, merged, and this weld line was generated. In this case, there is a problem in that the appearance and strength of various products using the molded product are greatly affected.

In order to solve these conventional problems, the present invention provides a mold for injection molding of a polymer material, which aims to prevent the occurrence of weld lines by installing a heating device inside the mold. The goal is to obtain

[0005]

[Means for Solving the Problems] The injection molding mold for polymeric materials of the present invention is characterized in that a heater is installed inside the mold.

[0006]

EXAMPLES The present invention will be explained in detail below based on examples.

As shown in FIGS. 3, 4, 5, and 6, the mold parts (1a, 1) near the weld line generation position of the injection molded product 2
Drill a hole like 3 into which the heater 4 will be inserted (at any position of both the fixed and movable molds shown in b) and attach the heater. Since the heater can be controlled arbitrarily from the outside, it is possible to increase the temperature distribution of the mold to a high temperature only at the position where the weld line occurs.

As mentioned above, the cause of the weld line is that the polymer material passes through the polymer material filling channel 5 (hereinafter referred to as runner) and the gate and begins to cool and solidify in the injection molded product filling part 2. This is due to the merging of materials that have been mixed together, so by locally increasing the temperature of that area using the method described above, it is possible to promote the mixing of materials and prevent the occurrence of weld lines, which is a problem in the past. I can do it.

[0009]

Effects of the Invention The above-described partial temperature control method in the injection molding process of polymeric materials of the present invention locally increases the temperature of the material by installing a heater inside the mold, and as a result, the weld It is possible to prevent the occurrence of lines, and it is possible to improve the appearance and strength factors of products using the molded product.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an injection molded part.

FIG. 2 is a plan view seen from arrow A in FIG.

FIG. 3 is a perspective view showing an embodiment according to the present invention.

FIG. 4 is a sectional view taken along line AA in FIG. 3;

FIG. 5 is a cross-sectional view taken along line BB in FIG. 3;

FIG. 6 is a sectional view taken along line CC in FIG. 3;

[Explanation of symbols]

1a Mold (fixed side) 1b Mold (moving side) 2 Molded products 3 Cavity for insertion of heater 4 Heater 5 Runner and gate

Claims (1)

[Claims] 1. A mold for injection molding a polymeric material, characterized in that a heater is installed inside the mold.