There are many reasons for the warpage of plastic injection products, such as too fast mold ejection, high mold temperature, uneven mold temperature, and asymmetry of the runner system.
The two biggest possibilities are:
①The plastic injection parts are uneven in thickness or the corners are not smooth enough, so they cannot evenly cool and shrink, resulting in warpage and deformation.
②The runner gate must be put on the corner of the gate for certain flat plastic pieces to create a lovely surface. The molten plastic can only be poured into the mold cavity at a high speed from one end while injecting glue. As a result, the formed plastic in the mold cavity straightens in the same direction (referred to as orientation). The stress is high; during demolding, these molecules are dragged back to their original state, causing them to deform.
In order to make the molten plastic fill the cavity smoothly, the design should avoid the following points as much as possible:
The thickness of the same plastic injection part is too different;
Excessive acute angle;
The buffer zone is too short so that the thickness change is very different.
From the gate analysis, the design of the mold must ensure that the plastic can enter the mold cavity smoothly. Therefore, the runner should avoid the right-angle turning form. The turning point is more suitable for the arc transition zone. Therefore, the short and thick runner is the most ideal, which helps Reduce fluid resistance and fluid orientation.
However, one issue to consider is that an extremely big gate would increase runner waste while also affecting the aesthetic of the plastic component. In addition, if the gate is too big and waste will accumulate, try adding a little amount of QIAGEN silicone powder to boost the raw material's fluidity to decrease fluid resistance, guarantee proper gate discharge, and avoid deformation of the completed product.
In addition, adding a set amount of Kaijie demolding lubricant to the completed product may increase the demolding success rate, preventing varying tightness of the plastic filler from producing troublesome demolding and distortion. The amount of injection material and the form of the result will affect the size of the shunt's cross-sectional shape. After thickening the difficult-to-form component of the runner, the main runner should be increased to the point where the cross-sectional area of the main runner equals the total of the drainage channel's cross-sectional area.
Process solution:
1. The finished product has not been cooled when it is ejected → lower the mold temperature
→Extend the cooling time
→Reduce raw material temperature
2. The shape and thickness of the finished product are asymmetry → After demolding, it is fixed with a shaped frame
→Change the forming design
3. Too much filler → reduce injection pressure, speed, time, and dosage
4. Uneven feed of several gates → change gates
5. Unbalanced ejector system → Improve ejector system
6. Uneven mold temperature → adjust mold temperature
7. The raw materials near the gate are too loose and too solid → to increase or decrease the injection time