JP6425235B1 - Injection molding method and method for preventing blowout - Google Patents

Abstract

An object of the present invention is to find a preferable condition of a product at a resin melting temperature under molding conditions in resin injection molding, and in many cases, to raise the temperature as much as possible. Even if the temperature does not reach the limit temperature of the resin, there are cases where product defects occur due to phenomena such as dripping of resin while waiting from the tip of the nozzle or phenomenon such as ithiki pulling the product without cutting off the product properly when taking out the product. is there. Provided is a sprue bush (mold part) that prevents such a defect. SOLUTION: The resin has a flow path of resin incorporated in the sprue bush 3 by using an operation in a direction perpendicular to the mold opening such as opening and closing operation of the mold and forward and backward movement of the nozzle by sprue break. Rotate the parts. This mechanically shuts off the flow path near the mold inlet. Using this mold operation and sprue break is consistent with the timing to shut off during injection standby. [Selected figure] Figure 1

Description

  The present invention relates to an injection mold for preventing blowout and blowout during injection molding.

  The injection of the resin from the injection molding machine into the mold is performed with the nozzle tip of the injection molding machine in contact with the sprue bush of the mold (nozzle touch). The resin of the molding material is melt-kneaded in the cylinder portion of the molding machine and injected and molded from the injection nozzle attached to the end of the cylinder to the product shape portion of the mold at high pressure.

  The fluidity of the resin at the time of injection molding is important for product quality, and the degree of fluidity and the relationship between temperature and fluidity are characterized by the resin. For this reason, some resins may be injected into a mold in a state of high flowability at high temperature.

  If resin flowability is increased at the injection nozzle in order to reduce the injection resistance, soaking occurs when the sprue is separated from the so-called dripping or the nozzle where the resin leaks from the nozzle hole even when taking out the product after the injection is stopped. The leaked resin may cause molding failure if it can not be stored in the cold slug if the fluidity is reduced in the sprue hole. Further, since the amount of leakage is not constant, the amount of injection resin varies, and the molding conditions are not determined, which also leads to molding failure. In the case of ithiki, the resin resin may adhere to the product to cause molding failure, and the resin resin may adhere to the mold and pinch the mold to damage the mold. This may interfere with unmanned molding.

  At the time of taking out the molded product, the resin prepared for the next injection operation is melted and kneaded on the cylinder side, and the resin pressure at the injection nozzle portion becomes high, which may promote the dripping phenomenon. In such cases, the shut-off nozzle is effective but it has limited resin availability and is expensive.

JP 06-068810 A

  An object of the present invention is to provide a sprue bush (mold part) in which so-called "Hanataro 28" and "Tohiki 29" are prevented.

  2 (a, b) and 15 (a) in which the vertical movement of the mold opening and closing 7, 8, 9, 20, 21 and the nozzle 24 during the injection molding is linked to the movement in the vertical direction with respect to the mold The rotary shaft parts 1 (a, b) and 14 (a, b) having a resin passage according to (b) and (b) rotate to seal the resin of the flower. In addition, it cuts in the crush. The rotation method of the rotary shaft parts 1 and 14 uses the sliding movement of the parts 2 and 15 arranged vertically to the mold and fixes the rotary parts 2 and 15 and the rotary shaft parts 1 and 14. It is done by moving vertically to the mold in the state of being hooked to 2 and 15.

  Because a small amount of resin is left in the resin passage of the rotating shaft parts when cutting the resin pouring area of the sprue bush 3 and 16 that the nozzle 24 touches and when cutting the axillary stroke, it is an amount that can be planned, By providing the cold slugs 6, 19 properly, it is possible to prevent the product and the runner from being filled with the resin of the flowering and the beard.

  FIG. 1 illustrates the structure of a three-plate mold, and in the molds 7, 8 and 9 on the fixed side, the main fixing mold of 9 continues to move in the direction of 10 and the stripper plate 8 moves in the direction of 11 At this time, when the cylinder 4 moves together with 8 and the distance 13-a from the entrance of the sprue bush 3 to the resin passage end of the rotary shaft part 1 exceeds the part 13-a, the rotary shaft part 1 is rotated by the part 2.

  FIG. 2 illustrates the structure of a two-plate mold, in which the main mold 21 on the movable side moves in the direction of 22 and the molded product 18 is pulled to the movable side. When the sprue end exceeds the distance 23-a from the entrance of the sprue bush 16 to the resin passage end of the rotary shaft part 14, the spring 25 for sprue breaking (lowering the nozzle) of the nozzle 24 works and the bush in the opposite direction of 22 The rotating shaft part 14 rotates in conjunction with this movement of moving 16.

  FIG. 3 illustrates an image of the rotary shaft parts 1 and 14 and the parts 2 and 15.

Effect of the invention

  It is possible to mechanically prevent so-called "Hanatalee-Itokiki" which is a problem in resin molding. Although the melting temperature of the resin, which is conventionally required as the molding condition, could not be implemented due to the peeling and itching, it is possible to raise the melting temperature by mechanically preventing it.

  Even if the melting temperature is not raised so much at the time of resin molding, it may happen that it is not automatic molding but mandatory molding. You are freed from such inefficient work.

  Example (when hatching is partially omitted) when the present invention is carried out using a three-plate mold   Example (when hatching is partially omitted) when the present invention is carried out with a two-plate mold   1, 2 in FIG. 1 and 14, 15 in FIG. 2   Image of Hanataroe (some hatching omitted)   Image of Itohiki (some hatching omitted)

1-a Rotary shaft part 1-b when mold is closed Rotary shaft part 2 when mold is opened 2-a Force is applied to rotary shaft part in a direction perpendicular to the mold when the mold is closed Parts 2-b Parts that apply force to the rotating shaft parts in a direction perpendicular to the mold when the mold is opened 3 sprue bush 4 cylinder 5 molded part 6 cold slug 7 fixed mounting plate 8 stripper plate 9 fixed main mold 10 fixed main Die release direction 11 Stripper plate release direction 12 Necessary distance 13 for rotating the rotating shaft part 13 Distance for the product spline to exceed the end of the rotating shaft part 14-a Rotation when the mold is closed Shaft part 14-b Rotary shaft part 15-a when the mold is open Part 15-b that applies a force in the vertical direction to the mold when the mold is closed Part 15-b metal when the mold is open Mold and vertical force rotating axis Parts to be provided 16 sprue bush 17 cylinder 18 molded article 19 cold slug 20 fixed main mold 21 movable main mold 22 mold opening direction of fixed main mold 23-a sprue bush distance from rotary shaft part end 23-b sprue bush Distance 24 from the inlet to the end of the rotating shaft part No. 25 of the forming nozzle 25 Enlargement of the enlarged images 26-b 2 and 15 of the springs 26-a 2 and 15 Enlargement of the enlarged images 27-b 1 and 14 of the enlarged images 27-a 1 and 14 Image 28 Image of Hanataroe 29 Image of Itohiki

Claims (1)

In injection molding , a rotary shaft part provided with a flow path (movement in the vertical direction with respect to the mold due to opening and closing of the mold or sprue break (forward and backward movement of the nozzle) near the resin inlet of the sprue bush In this case, 1-ab 14-ab 27-ab is taken as an example), and in conjunction with the movement, the rotary shaft part is rotated to block the sprue bush's flow path, thereby How to shut off mechanically .

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