Thermoforming concept

A variation of thermoforming which does not involve gas pressure or vacuum is matched die forming. The concept is very simple and is illustrated in Fig. 4.53. The plastic sheet is heated as described previously and is then sandwiched between two halves of a mould. Very precise detail can be reproduced using this thermoforming method but the moulds need to be more robust than for the more conventional process involving gas pressure or vacuum. 

Designers and processors to produce products at the lowest cost have unconsciously used the basic concept of the FALLO approach. This approach makes one aware that many steps are involved to be successful, all of which must be coordinated and interrelated. It starts with the design that involves specifying the plastic, and specifying the manufacturing process. The specific process (injection, extrusion, blow molding, thermoforming, and so forth) is an important part of the overall scheme and should not be problematic. 

A simple approximation of the thermoforming process is based on a mass balance principle. To illustrate this concept, let us consider the thermoforming process of a conical object, as schematically depicted in Fig. 6.25. 

The system s key concept is a specially designed and patented frame, integrated into the mould, which is specifically designed to hold the film in position during this thermoforming process. This frame can be either two or three dimensional, to better follow the shape and the cavities of the mould (see Figure 3.15). 

The modeling of the inflation and solidification portions of blow molding and thermoforming do not introduce major new concepts beyond those incorporated in... 

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