The Cause And Countermeasure Analysis Of Shrinkage In Products
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Shrinkage refers to the depression of the product table and the production of insects, like hair in the thicker part of the wall. In the process of cooling the molten resin from the external part, when the volume shrinkage cannot be compensated, the resin on the surface of the formed product is subjected to the volume shrinkage of the molten resin in 6 parts, resulting in the formation of q marks.
| Cause | Cuntermeasure | |
| Forming condition |
1. There are many cases of insufficient pressure and retaining pressure during the injection period 2. The pressure retention time is insufficient 4. The mold temperature is not appropriate, the mold temperature is too low, the gate curing fast, pressure retention failure is easy to produce shrinkage hole: the mold temperature is too high, setting the appropriate mold temperature is easy to produce shrinkage marks 5. The injection speed is too fast The temperature of the material is too high, and the shrinkage of the material is too large |
1. Increase the injection pressure and pressure holding pressure; 2. Increase the pressure raising time 3. Increase the measurement distance 4. In thick products, this tendency is stronger and the speed is reduced 5. Properly reduce the temperature of the material
|
| Die |
1. The runner and gate are too small. 2. Improper placement of pouring II makes the material flow distance too long 3. Insufficient or inconsistent mold cooling
|
1. Increase the section of runner and gate 2. Review runner and gate 3. Check the cooling system
|
| Product Design |
1. Uneven thickness 2. The shape of tendons is not standard
|
1. Avoid uneven thickness, can use stolen thick pin or groove. 2. Avoid thick and long tendons |
| Material |
1. The shrinkage rate of materials is too large 2. Poor material fluidity
|
1. Switch to materials with low shrinkage 2. Improve material mobility |
| Other | Screw check ring is damaged | Replace the check ring |
