Description
Reasons and solutions for bubbles in injection molded PP products. Bubbles in injection molded PP products:
PP bubbles solve problem one:
- Increase the mold temperature and reduce the injection time and cycle “Because PP bubbles are formed due to internal shrinkage caused by too long cooling time”
- Increase the back pressure and extend the injection time. Use high pressure and low speed.
PP materials generally do not have bubbles (due to low moisture absorption). There may be a problem with the filler during granulation of PP materials. If the solution in terms of technology is: 1. Add raw materials for baking. 2. Increase the injection back pressure and slow down the injection speed. 3. The barrel temperature should not be too high.
PP material is originally a very easy material to work with. 1. First consider your mold structure and where the bubbles are formed. 2. The temperature of the bubble tube should not be too high. 3. The thickness of the product. 4. Try it without glue extraction/or use less glue. In fact, when adjusting injection molding efficiency, don’t just look at the parameters. That would be boring. The right way is to analyze the problems more. Sometimes, adjusting the machine is not just about counting the five major components.
PP bubbles solve problem two:
- The material storage speed is too fast. Add some back pressure appropriately.
- The raw materials are not dry enough and contain moisture.
- The plastic stays in the barrel for too long.
- The screw backshot is too long.
- Poor mold exhaust.
- The injection pressure is too small and the injection speed is too high.
- The melt temperature is too high and the mold temperature is too low.