The occurrence of deformation, bending and twisting of Rigid vinyl compound injection products is mainly due to the fact that the shrinkage rate in the flow direction is greater than that in the vertical direction during plastic molding, which makes the parts shrink and warp due to different shrinkage rates, and it is inevitable during injection molding. There is a large internal stress left in the part to cause warpage, which are manifestations of deformation caused by high stress orientation. So fundamentally speaking, mold design determines the warpage tendency of the part. It is very difficult to suppress this tendency by changing the molding conditions. The final solution to the problem must start with mold design and improvement. This phenomenon is mainly caused by the following aspects:

1. Mould aspect:

(1) The thickness and quality of the parts should be uniform.

(2) The design of the cooling system should make the temperature of each part of the mold cavity uniform, and the pouring system should make the material flow symmetrical to avoid warping due to different flow directions and shrinkage rates, and appropriately thicken the runners and mainstream of the difficult-to-form parts Road, try to eliminate the density difference, pressure difference, and temperature difference in the cavity.

(3) The transition zone and corners of the thickness of the part should be smooth enough and have good mold release. For example, increase the mold release margin, improve the polishing of the mold surface, and maintain a balance in the ejection system.

(4) Good exhaust.

(5) Increase the wall thickness of the part or increase the direction of anti-warping, and strengthen the anti-warping ability of the part by reinforcing ribs.

(6) The strength of the material used in the mold is insufficient.

2. Plastic aspect:

Crystalline plastics have more chances of warping deformation than non-crystalline plastics. In addition, crystalline plastics can use the crystallization process of crystallinity to decrease with the increase of cooling rate and shrinkage rate to correct warping deformation.

3. Processing aspects:

(1) The injection pressure is too high, the holding time is too long, and the melt temperature is too low and the speed is too fast, which will cause the internal stress to increase and warp deformation.

(2) The mold temperature is too high and the cooling time is too short, so that the part is overheated during demolding and ejects deformation.

(3) Reduce the screw speed and back pressure to reduce the density while keeping the minimum Rigid vinyl compound filling amount to limit the generation of internal stress.

(4) If necessary, the parts that are prone to warpage and deformation can be soft-shaped or demolded and then returned.

Wuxi Jiahong Plastic Technology Co., Ltd. has nearly 30 years of experience in R&D and pelletizing production of Rigid vinyl compounds, and experience in R&D and production of modified engineering plastics; the professional technical service team can provide customers with one-stop modified plastic system solutions. If you want to know more about the product, please log in to our official website: www. js-plastics. com, consult online customer service or call the hotline. Landline: 0510-68755207 Mobile: 15190220696, we will serve you wholeheartedly.