JP2002283417A - Mold for molding resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for molding a resin capable of cutting a gate in the mold though the structure of the mold has a two-plate structure and capable of dispensing with gate treatment in a rear process. SOLUTION: The mold 1 for molding the resin is constituted so that a runner part 8 and a gate part 9 are formed on the surfaces of the slide core parts 4 and 4' sliding on the parting surface 21a of a fixed mold 2 and a movable mold 3 corresponding to the on-off operation of the movable mold 3 and, when the movable mold is opened after the molding of the resin, the gate is cut by sliding the slide core parts while holding the product part molded in a cavity part 7 by the fixed mold or the movable mold. The runner part 8 is formed so as to straddle two slide core parts while the gate part 9 is formed to either one of the slide core parts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molding die, and more particularly, to a resin molding die having a slide core and utilizing its movement to enable gate cutting in the die.

[0002]

2. Description of the Related Art In resin molding, a gate is located at the end of a runner and is an injection port of molten resin into a cavity, which is an important part that greatly affects the quality and productivity of a molded product. The gate should have as little resistance as possible while the resin is flowing into the mold. On the other hand, once the mold is filled, it is desirable to cool and solidify as soon as possible to contain the resin in the cavity.

Conventionally, there are a side gate method and a pin gate method as shown in FIG. 4 as a method of providing a gate in a portion formed by a slide core. In the side gate method, as shown in FIG.
The first and second slide cores A2 have a runner portion B and a gate portion C on their surfaces, respectively. Therefore, although the mold structure is a two-piece structure, the gate cannot be cut in the mold, and the product part D ′ (cavity part D) and the runner B ′ are connected by the gate C ′. Since the material is discharged from the mold, a gate process in a later process is required.

In the pin gate system, as shown in FIG. 4 (b), a runner portion B and a gate portion C are provided on the mold side, and the gate openings thereof are in the sliding direction of the slide cores A1, A2. It faces the split surface of the slide core at a substantially right angle. For this reason, in this pin gate method, gate cutting can be performed in the mold, and the product part D 'and the runner B' can be separated. However, since the runner B 'needs to be discharged from the mold, three mold structures are required. There is a problem that the mold structure is required, and the cost and cycle time of the mold are increased.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to perform gate cutting in a mold even though the mold structure is a two-piece structure. An object of the present invention is to provide a resin molding die that can eliminate gate processing in a post-process and is improved in cost, cycle time, and post-finishing.

[0006]

According to the present invention, as a means for solving the above-mentioned problems, there is provided a resin molding die described in each of the claims. In the resin molding die according to the first aspect, a runner portion and a gate portion are formed on a surface of a slide core that slides on a split surface between a fixed die and a movable die according to an opening and closing operation of the movable die. When the movable mold after resin molding is opened, gate cutting can be performed by sliding the slide core while holding the product part molded in the cavity part with the fixed mold or the movable mold. Thus, the die structure is a two-piece structure, gate cutting can be performed by sliding the slide core, and gate processing in a later process can be eliminated.

According to a second aspect of the present invention, the slide core is composed of first and second slide cores which are divided and which can be separated from and separated from each other, and the runner extends over both slide cores. On the other hand, the gate portion is formed on one of the slide core portions.
According to a third aspect of the present invention, the resin molding die is formed on the surface of the slide core portion such that the gate portion forms a predetermined angle with respect to the divided surface of the slide core portion. As a result, the gate can be effectively cut without forcibly removing the gate.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a resin molding die according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a longitudinal sectional view in a state where a resin molding die 1 of the present invention is closed, and a partially enlarged sectional view taken along line AA. FIG.
1 is a longitudinal sectional view in a state where a resin molding die 1 is opened, and a partially enlarged plan view of a slide core. FIG. 3 is a sectional view taken along line BB of FIG. The resin molding die 1 of the present invention basically includes a fixed mold 2, a movable mold 3 movable with respect to the fixed mold 2, and a fixed mold 2 and a movable mold 3 in accordance with opening and closing operations of the movable mold 3. And first and second slide cores 4 and 4 'that slide on the dividing surface between the first and second slide cores.

The fixed mold 2 has a fixed body 21 serving as a base.
And a fixed mounting plate 23 for fixing the fixed die 2 to the equipment.
A spacer block 22 for connecting the fixed die body 21 and the fixed die mounting plate 23; an ejector pin 24 for separating the molded product 7 'from the fixed die 2 after molding; and upper and lower ejector plates for holding the ejector pin 24. 25. The fixed die 2 is provided with inclined holes 2a and 2a 'for guiding a pair of angular pins described later.

The movable mold 3 includes a movable body 31 serving as a base.
And a movable mounting plate 3 for fixing the movable die 3 to a movable part of the equipment
2 is comprised. The movable die 3 has a pair of angular pins 5 and 5 ′ mounted in an inverted V-shape and also has nested pins 6.

[0011] on the surface 21a of the stationary mold 2 and movable mold 3 to be on the split surface fixed body 21 includes a first pair of sliding on this surface a second slide core 4, 4 ' Are provided. These slide cores 4, 4 'have inclined holes 4a, penetrating therethrough for guiding the angular pins 5, 5'.
4a 'is perforated. Therefore, in accordance with the opening and closing operation of the movable mold 3, the pair of slide cores 4, 4 'are restrained by the angular pins 5, 5', and slide laterally with each other.
Contact and detach. In a state where the movable mold 3 is closed, as shown in FIG. 3, the fixed mold 2, the movable mold 3 and the slide cores 4 and 4 'surround the insert pin 6.
A cavity part 7 corresponding to the product part 7 'is formed.

Next, features of the present invention will be described.
As shown in FIGS. 1 to 3, a runner portion 8 is formed on the surface of each of the pair of left and right first and second slide core portions 4 and 4 'in a shared manner. A gate portion 9 is formed between the runner portion 8 and the cavity portion 7 and communicates between them. The gate portion 9 is formed independently on the surface of one of the first and second slide core portions 4 and 4 '(the first slide core portion 4 in FIGS. 1 and 2). The shape is substantially a truncated semi-conical shape. Further, the gate section 9 is formed such that the center line of the gate section 9, that is, the center line of the substantially semi-frustroconical shape forms a predetermined angle θ (for example, 30 to 60 degrees) with the division surface 4 c of the slide core sections 4 and 4 ′. 9 are formed. Therefore, on the surface of the first slide core portion 4, as shown in FIGS. 1 and 2, an isolated A portion having an acute angle portion surrounded by the cavity portion 7, the runner portion 8, the gate portion 9, and the dividing surface 4c. 4b is formed.

Next, the operation of the above configuration will be described.
When the molten resin is injected from a nozzle (not shown) in a state where the movable mold 3 in FIG. 1 is closed, the molten resin passes from the runner section 8 through the gate section 9 to the cavity section 7.
Is injected into. Then, the resin in the runner portion 8, the gate portion 9 and the cavity 7 is solidified to form the runner 8 ', the gate 9' and the product portion 7 '.

Thereafter, when the movable mold 3 starts to be opened, the first and second slide core portions 4, 4 'are guided by the angular pins 5, 5', respectively, and move on the fixed mold 2 in directions opposite to each other. After sliding, the first and second slide cores 4, 4 'are opened, and the state shown in FIG. 2 is obtained. At this time, the acute angle portion of the A portion 4b of the first slide core 4 automatically cuts the tip of the gate 9 'connecting the gate 9' and the product portion 7 '. With further movement of the first slide core 4, the gate 9 ′ comes out of the gate 9 while deforming. Thus, the gate 9 'and the product part 7' are automatically separated by the movement of the first slide core part 4. Next, the product part 7 'is pushed out of the mold by the ejector pin 24, or taken out of the mold by a pickup means (not shown).

As described above, in the resin molding die of the present invention, the gate is automatically cut by the operation of the slide core, and the runner is separated from the product part. The processing can be omitted. In addition, since the gate cut can be performed by using a two-piece mold structure, the cost of the mold and the cycle time can be reduced.

[Brief description of the drawings]

FIG. 1 shows a longitudinal sectional view of a mold for resin molding according to an embodiment of the present invention in a state where a movable mold is closed, and a partially enlarged sectional view taken along line AA.

FIG. 2 shows a longitudinal sectional view of a resin molding die according to an embodiment of the present invention with a movable die opened, and a partially enlarged plan view of a slide core.

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

FIGS. 4A and 4B show a conventional method of providing a gate at a portion formed by a slide core, (a) a side gate method, and (b).
It is a figure explaining a pin gate system.

[Explanation of symbols]

 2 ... fixed type 3 ... movable type 4, 4 '... first and second slide core parts 5, 5' ... angular pins 6 ... nested pins 7 ... cavity parts 7 '... product parts 8 ... runner parts 8' ... Runner 9 ... Gate 9 '... Gate

Claims (3)

[Claims] 1. A resin molding comprising a fixed mold, a movable mold movable with respect to the fixed mold, and a slide core that slides on a dividing surface between the fixed mold and the movable mold in accordance with an opening and closing operation of the movable mold. In the mold for use, a runner portion and a gate portion are formed on the surface of the slide core, and when the movable mold is closed, a cavity is formed by the fixed mold, the movable mold and the slide core. When opening the movable mold after resin molding, gate cutting is performed by sliding the slide core while holding the product part molded in the cavity by the fixed mold or the movable mold. A resin molding die. 2. The method according to claim 1, wherein the slide core is divided into two first and second slide cores which can be separated from each other, and the runner is formed so as to straddle both slide cores. The resin molding die according to claim 1, wherein the gate portion is formed on one of the first and second slide core portions. 3. The slide gate according to claim 2, wherein the gate formed on the surface of the slide core is formed at a predetermined angle with respect to a division surface of the slide core. Mold for resin molding.