... packing. The addition of fillers to the plastic can increase the strength of the productbut will also affect the shrinkage factors, usually reducing them. This meansthat the size of the product ... in theirretainer plates, there is little wear to expect. But even under the bestconditions, after the mold is in operation for a long time, the clearance in the bores will increase, and the ... pin or other obstacle breaks the flow into twoseparate streams. In some products, these weld lines can be objectionable foraesthetic reasons; in others, they may be acceptable. When the plastic...