What are the common problems of mold trial

Update: 15-10-2021

Mold workers always have some problems when they try ou […]

Mold workers always have some problems when they try out molds. Kejie Mold has also encountered them in their previous work. Today, I will make a brief summary of some common problems in mold tryouts:
1. Insufficient plastic parts: mainly due to insufficient material supply, poor filling flow of molten material, excessive inflation and poor exhaust, etc., which lead to unsatisfactory filling of the cavity, incomplete and incomplete shape of the plastic part, or unsatisfactory filling of individual cavities when there are multiple cavities.
2. Dimensional instability: mainly due to poor mold strength, poor precision, unstable operation of the injection machine and unstable forming conditions, which make the dimensional change of the plastic part unstable
3. Air bubbles: due to excessive inflation or poor exhaust in the molten material, there is residual gas in the plastic parts, and they are small in volume or in series of cavities (note that it should be distinguished from vacuum bubbles)
4. Collapse (dent) or vacuum bubble: due to poor pressure holding and refilling, uneven cooling of plastic parts, uneven wall thickness and large shrinkage of plastic
5. Excessive flash: due to poor clamping, the gap is too large, the fluidity of the plastic is too good, and too much material makes the plastic part squeeze out excess flakes along the edge
6. Poor welding: Due to the low temperature of the melt when the melt is merged and the resin is incompatible with the agglomerate, the melt will be poorly welded when the melt is merged, and there will be obvious thin seam lines along the surface or inside of the plastic part.
7. The surface of plastic parts is corrugated: because the molten material does not flow neatly along the mold surface to fill the cavity, but flows into a semi-solidified wave shape on the surface of the cavity or the molten material has stagnant flow
8. Poor demolding: Due to excessive filling effect and poor mold demolding performance, it is difficult to demold the plastic part or the plastic part is deformed or broken after demolding, or the residual direction of the plastic part does not meet the design requirements.