- July 26, 2019
- Posted by: Molding
- Category: Industry News
It is well known that in the plastic processing process, if various parameters are not well controlled, the plastic products are prone to shrinkage after being shaped, thereby affecting the precision of plastic processing. So, what are the adverse effects of shrinkage on plastic processing? Let’s take a look at it below:
1. Shrinkage after processing:
The shrinkage of plastics can be divided into two types: forming shrinkage and shrinkage after processing.
The shrinkage after processing is the shrinkage of the products after a period of time after demolding, and the post-shrinkage is generally small compared to the molding shrinkage.
The first cause of post-contraction is the relaxation of the internal stress of the article. For polymers with a rigid molecular chain, the post-contraction of the product is relatively large; this is mainly because the rigid molecular chain moves slowly, and its molecular chain changes from one state to another, requiring a long realignment process.
Therefore, the post-shrinkage time is relatively long, and the post-shrinkage rate is relatively large. On the other hand, rigid molecular chains tend to generate internal stress, and slowly stress relaxation occurs after molding. The second cause of post-contraction is the continued crystallization. For the complete crystallization, and the crystallization can continue at normal temperature, thereby causing a slight shrinkage of the product.
2. Average shrinkage rate:
Since the shrinkage size of plastic processing is greatly affected by the molding conditions, the shrinkage rate is not a fixed value, but a range. In the specific processing process, various processing conditions can increase the molding shrinkage rate, and 4% can be selected.
For specific shrinkage, if the specific molding conditions are favorable for the reduction of molding shrinkage, then 2.5% can be selected as the specific shrinkage. Of course, the latter method is more difficult.
About JasonMould Industrial Company Limited
Jasonmould is a China mold maker of plastic molds- injection mold, die casting moulds, plastic blow molding, rotational molding, medical plastic injection molding, two shot plastic injection molding, insert molding, overmolding, metal injection molding, micro injection molding, powder injection molding, ceramic injection molding, liquid injection molding, husky injection molding, household mold, casting mold, die mold tool, custom molds, china moulds, rapid prototyping tooling, plastic prototyping tooling, punch press tooling, die and tooling for mobile/ cell phone parts, automotive parts, vacuum cleaners, rechargeable tools, telephones, copiers, computers, multimedia speakers, and many other electronic products and household appliances. And also a plastic product manufacturer, mold manufacturer China– plastic parts, plastic water tank, plastic balls, plastic containers, plastic buckle, plastic anchor, plastic hanger, plastic spoon, plastic pipe fitting, plastic tumble, plastic tableware, plastic cups, plastic bottles, plastic tray, plastic cosmetic container, plastic case, plastic food container, plastic chairs, plastic caps, plastic cap closure, plastic tubes, plastic water pipes, plastic knobs, plastic tubing, plastic utility boxes, plastic racks and so on.
Person: James Yuan
Company: JasonMould Industrial Company Limited
Add: LongGang Village,LongXi Town,BoLuo County,HuiZhou City,GuangDong Province, China
Email: [email protected]