Our common plastic and composite processing and molding process have extrusion, blow molding, injection molding, etc., in addition, rolling plastic products is also a processing method. The rolling molding process is from the 1930s, after the development of equipment and technology has developed mature.

Today's toys are made by rolling plastic forming, from small children's toys to common automobile plastic parts to huge engineering plastic products, especially super large and non-standard hollow plastic products. Due to the limitation of plastic processing technology itself, it can only be completed by rolling molding process.

Rolling plastic mainly used in thermoplastic materials, crosslinked polyethylene and other thermosetting materials also developed rapidly. Because roll-molding does not require high injection pressure, high shear rate, or accurate polymer gauges, molds and machines are relatively inexpensive and have a long service life.

In the rolling molding process, if the wall of the product is required to be high compressive strength, whether to design reinforcement or "kiss" structure on the product. Does the design include a deeper side trap in the direction of product release? If so, they must be designed on the outside or as live inserts, so the mold cost will increase. Small dents can be left out because of the plastic's contractibility. But you have to know how deep the sag is and you don't need additional molds.

There are two rolling moulds in standard cases, but multiple moulds may be required if the design of the product is more complex. This will affect the mold cost, mold maintenance and the cost per piece of plastic products. Pay attention to the design size of the rolling plastic mold, generally speaking, the shrinkage of rolling plastic products in about 3%, if the rolling plastic products on the high dimensional accuracy requirements, but also from the raw material parameters, the internal structure of the product, the shrinkage of the mold material to do analysis and adjustment.

The degree of surface treatment not only has a great impact on the mold cost, but also sometimes the specific surface treatment will affect the product demoulding. Whether the rounded corners in the design are large enough for the resin to flow freely to every part of the mold, and what is the sufficient radius of the rounded corners; Whether to use inserts to attach other parts to plastic products. How the inserts are positioned, whether they will remain in state during the molding operation, and so on are considered.