Thermoforming annealing

Copper materials can be very well polished in the hardened state. The achievement of a homogeneous, mirror-like surface depends on a particularly fine and very uniform structure. A thermoformed, annealed semifinished part usually has such a structure. 

The polymer should be dried before processing and typical melt temperatures are 340 to 425°C.2 Polyetherimides can be processed by injection molding and extrusion. In addition, the high melt strength of the polymer allows it to be thermoformed and blow molded. Annealing of the parts is not required. 

The thermoforming process is the method for annealing a sheet of thermoplastic resin to manufacture the final product by vacuum or air pressure, as shown in Fig. 6.9. It has these advantages The cost of equipment is inexpensive, the processing of multilayer sheets can be readily achieved, and the production of thin products is possible. The disadvantages of this process are that the procedure for preparing sheets is necessary, the selection of available plastic material is limited, and manufacturing with accurate dimensions is difficult. 

---