Core-pulling mechanism of injection mold and injection mold

Abstract

The invention discloses a core-pulling mechanism of an injection mold. The core-pulling mechanism is used for forming a sinking hole and comprises a first motion station, a second motion station, an elastic element and a motion station seat. The second motion station is sleeved in the first motion station in a sliding manner, the front end of the second motion station stretches out of the front end of the first motion station, the front end of the first motion station is used for forming a large hole of the sinking hole, and the front end of the second motion station is used for forming a through hole of the sinking hole. The first motion station is provided with a first limiting portion, the second motion station is provided with a second limiting portion, and the first limiting portion and the second limiting portion are spaced by a certain gap in the work state. The rear end of the first motion station and the motion station seat are fixed. The elastic element provides elastic forceenabling the front end of the second motion station to stretch out of the front end of the first motion station. According to the core-pulling mechanism of the injection mold, flashes can be effectively prevented from being generated during injection molding of the sinking hole, the injection molding yield can be improved, and the difficulty and cost of mold design and manufacturing can be reduced. In addition, the invention discloses the injection mold.

Description

technical field [0001] The invention relates to an injection mold, in particular to a core-pulling mechanism of an injection mold and an injection mold with the core-pulling mechanism. Background technique [0002] In injection molding, it is often necessary to process a sink hole 201 on the product 200, such as figure 1 As shown, the existing method is to design a step structure 401 corresponding to the sinkhole 201 on a row position 400, and extend the step structure 401 into the cavity 503 of the mold composed of the front mold core 501 and the rear mold core 502 Inside, the oil cylinder is used to drive the movement of the position, so that the sink hole 201 is formed after injection molding. However, if figure 2 As shown, during injection molding in this way, the stepped structure 401 of the row position will be retreated by the relatively large injection pressure from the injection molding machine, and the size of the injection pressure depends on the shape of the p...

AI Technical Summary

Problems solved by technology

However, if figure 2 As shown, during injection molding in this way, the stepped structure 401 of the row position will be retreated by the relatively large injection pressure from the injection molding machine, and the size of the injection pressure depends on the shape of the product, the stress area of ​​the row position and the injection molding pressure. The required molding conditions (friction force and molding conditions cannot be calculated, can only be estimated), so it is impossible to calculate the pressure on the retreat of the row position, and it is possible that the molding conditions change slightly during the injection molding process This causes the row position to recede. Therefore, the existing structure cannot guarantee that the row position will not retreat or loosen due to the pressure given by the injection molding machine during the injection molding and pressure holding process.

As long as the distance of row position retreat is greater than 0.02mm, the molten plastic liquid will flow into the gap caused by the retreat or loosening of the row position, thereby causing flash 202 in the sink hole of the product and making the steps of the sink hole The surface 203 becomes thick or protruding, resulting in defective products and reducing the yield of injection molding

The existing repair of the above problems can only be done through accurate design calculations and a large number of tests and modifications, which greatly increases the difficulty of mold design and production and increases production costs.

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