Thermoforming mold design

The variety of forming equipment also provides wide contrast in thermoforming mold design. Factors to be considered are as follows ... 

The principal decision to be made when designing a thermoforming mold is to determine which of the two product faces is to be defined by the mold. As so many thermoformings are containers and are substantially cup or box-shaped, this decision determines whether the mold is to be of the male or female type. The shape of a thermoforming is sharply defined only on the surface in contact with the mold, so whichever is the primary presentation face of the product may determine the mold strategy. 

As is the case in molds for thermoforming, the design of injection molds must provide for venting to remove trapped air, which otherwise will mar the finish of the molded object, and may, in extreme cases, prevent accurate mold filling. The simplest way to accomplish this is to build vent holes into the mold parting line, where the core and the cavity come together. For large molded objects, this may be insufficient, and additional vents may be needed. 

The mold can be heated or used at ambient temperature, depending on mold design and final application. Parts up to 660-950 mm (2-3 feet) X 1.22 mm (0.048 in) thick can be formed in a matter of seconds. Thermoforming can also be used, to some extent, for preforming reinforced TP foam cores for laminating with TS resins. The Advance RP process (developed by Advance USA, East Haddam, CT, USA) is an adaptation of thermoforming for production of RPs. 

The finished product and the connected requirements, such as geometry, tolerances, number of parts, stackability, stiffness, and temperature resistance determine the mold design, the material choice, temperature control of the mold, the necessary forming process, and the thermoforming machine needed. 

Mathematical modeling can provide valuable insights into mold design and process improvement. The objective of computer simulation of thermoforming is... 

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. 

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