JPH10217281A - Filter for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a resin burning, scorching, a thermal deterioration and a thermal decomposition in a filter from generating by a method wherein a first protruding part is provided on a filter hole side on a closed wall, and a second protruding part is provided on a guide cylinder side. SOLUTION: A molten resin is fed in a cylindrical part 2 of a filter 1, and the molten resin being fed toward a closed wall 5, collides with a first protruding part 6, and reverses without staying on the closed wall. Then, the molten resin passes through filter holes, and foreign objects in the molten resin are removed, and then, the molten resin passes through a passage groove 4, an annular passage 7 and introduction holes 9 of a guide cylinder 8 in order, and is fed into the guide cylinder 8 to which an injection nozzle is attached. Then, the molten resin which is fed in the vicinity of the closed wall 5 in the guide cylinder 8 is smoothly fed to the injection nozzle in the direction along the stream of the molten resin without staying on the closed wall 5 by a second protruding part 10 which is provided on the closed wall 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding method for injecting a polyolefin resin such as polypropylene or polyethylene, or a molten resin such as nylon into a cavity to mold a product such as a synthetic resin cap or a synthetic resin inner plug. The present invention relates to a filter for injection molding used in a molding machine.

[0002]

2. Description of the Related Art An injection molding filter used in a conventional injection molding machine for injecting a molten resin is disclosed in Japanese Unexamined Patent Publication No. Sho 53-2.
1, 260, 60-260, 314, and
As seen in 206, 240, etc., a filter consisting of a large number of small holes or slits was simply attached in front of the nozzle hole of the injection nozzle.

[0003]

However, in a filter in which a filter hole is simply formed, even if foreign matters in the molten resin in the product can be removed, the molten resin remains in the filter, and the resin burns in the filter. It cannot prevent burning, thermal degradation and thermal decomposition of the resin.

In a filter having a small filter hole, a pressure loss of the injection pressure occurs. Further, even if the filter hole is simply formed in a slit shape, the pressure loss can be prevented, but the filter hole is not injected. It deforms due to pressure, and it is not possible to reliably remove foreign substances in the molten resin.

[0005]

According to the present invention, there is provided an injection molding filter comprising a cylindrical portion having a filter hole, a closing wall, and a guide tube having an introduction hole. An injection molding filter having a first projection on the filter hole side of the wall and a second projection on the guide cylinder side of the closed wall.

According to the present invention, in the injection-molded filter, the filter holes are formed in a slit shape and are provided in a staggered shape.

[0007]

According to the present invention, there is provided an injection molding filter in which the molten resin does not stay when the foreign material in the molten resin is removed and when the molten resin is subsequently supplied to the injection nozzle.

Further, according to the present invention, there is provided an injection molding filter which has a small pressure loss upon injection of a molten resin and can reliably remove foreign matters without causing deformation of a filter hole.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a filter for injection molding according to a first embodiment of the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 3 is a sectional view taken along line BB in FIG.

In the figure, reference numeral 1 denotes a cylindrical injection molding filter made of stainless steel or chromium-molybdenum steel or the like;
2 is a cylindrical portion, 3 is a filter hole, 4 is a flow channel, 5 is a closed wall, 6 is a first protruding portion, 7 is an annular flow channel, 8 is a guide cylinder, 9 is an introduction hole, and 10 is a second It is a protrusion.

As shown in FIG. 1, the filter 1 for injection molding comprises a cylindrical portion 2, a closing wall 5 and a guide tube 8, and a large number of small holes 3 are formed in the cylindrical portion 2. As shown in FIG. 2, the flow channel groove 4 having a width larger than the diameter of the filter hole 3 corresponding to the filter hole 3.
Are provided at equal intervals around the cylindrical portion 2 alternately with the partition walls 4a along the flow direction of the molten resin.

A first wall is provided on the filter wall 3 side of the closing wall 5.
A projection 6 is provided, the outer periphery of the closing wall 5 is defined as an annular flow path 7, and a second projection 10 is provided on the guide cylinder 8 side of the closing wall 5.
Further, as shown in FIG. 3, guide holes 8 are provided in the guide cylinder 8 at equal intervals so as to be located between the flow grooves 4 so as to be inclined downward in the flow direction of the molten resin. .

FIG. 4 shows a filter for injection molding according to a second embodiment of the present invention. The basic structure of the filter is the same as that of the first embodiment described above. The filter holes 3 formed of small holes provided in the portion 2 are formed as slit-shaped filter holes 3a and provided in a staggered manner.

FIG. 5 is a view showing an attached state of the injection molding filter 1 of the present invention.
Is mounted in the mounting cylinder 12 on the side of the injection plunger 11, and the molten resin is supplied from the plunger 11,
The nozzle hole 1 of the injection nozzle 13 through the filter 1
From 4, it is injected into a normal injection molding die (not shown).

A heater band 15 prevents the molten resin passing through the mounting cylinder 12 and the injection nozzle 13 from cooling.

The injection molding filter 1 of the present invention
As shown in FIG. 1 or FIG. 4, molten resin is supplied into the cylindrical portion 2 of the filter 1 from the left side of the drawing,
The molten resin supplied toward the closing wall 5 collides with the first protrusion 6 and flows backward without stagnation on the closing wall.

Next, the molten resin passes through the filter holes 3 or 3a, and after foreign matters in the molten resin are removed, the molten resin is introduced into the flow channel 4, the annular flow channel 7, and the introduction hole 9 of the guide cylinder 8. It sequentially passes and is supplied into the guide tube 8 to which the injection nozzle 13 is attached.

The molten resin supplied to the guide cylinder 8 near the closing wall 5 is supplied to the second protrusion 10 provided on the closing wall 5.
Accordingly, the molten resin is smoothly supplied to the injection nozzle 13 along the flow direction of the molten resin without staying in the closed wall 5.

In the present invention, the shape of the first projecting portion 6 and the second projecting portion 10 provided on the closing wall 5 may be a dome shape other than the conical shape shown in FIG. A plurality of projections may be provided, and the projections may be gradually reduced in diameter stepwise in the flow direction of the molten resin.

In the present invention, it is desirable that the shape of the flow channel 4 has the partition wall 4a because of good injection pressure efficiency. However, the shape of the channel groove 4 may not have the partition wall 4a.

Further, in the present invention, the annular channel 7 may have a shape having a partition, and the shape of the introduction hole 9 may be provided at a position corresponding to the channel groove 4.

[0022]

According to the present invention, when the molten resin is supplied to the injection mold, seizure and burning in the filter are prevented.

Further, since the seizure and burning of the molten resin are prevented, thermal deterioration and thermal decomposition of the molten resin supplied to the injection mold are prevented, and high quality of the injection molded product is maintained.

Further, the filter holes of the filter are formed in a slit shape and are arranged in a zigzag pattern, thereby preventing pressure loss at the time of injection molding and improving the strength of the filter hole to prevent deformation, thereby preventing foreign matter from being removed. Removal is ensured.

[Brief description of the drawings]

FIG. 1 is a view showing a filter for injection molding according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a view showing a filter for injection molding according to a second embodiment of the present invention.

FIG. 5 is a diagram showing an application example of the injection molding filter of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Filter 2 Cylindrical part 3 Filter hole 4 Channel groove 5 Closing wall 6 First projection part 7 Annular flow path 8 Guide cylinder 9 Introducing hole 10 Second projection part 11 Plunger 12 Mounting cylinder 13 Injection nozzle 14 Nozzle Hole

Claims (2)

[Claims] 1. An injection molding filter comprising a cylindrical portion having a filter hole, a closing wall, and a guide tube having an introduction hole, wherein a first projecting portion is provided on a filter hole side of the closing wall. A filter for injection molding, wherein a second projection is provided on the guide wall side of the closing wall. 2. The injection molding filter according to claim 1, wherein the filter holes are formed in a slit shape and are provided in a staggered manner.