Historical Review

1. What is thermoforming?
2. Is pressure forming something special?
3. Is it something new?
4. What can the process do for me?
5. Why should I consider it for my new product?
6. How does its cost compare with other processes?
7. What do I have to know in order to use pressure forming?

This booklet answers these seven most often asked questions and goes on to give you a clear understanding of the pressure forming process, its capabilities and its limitations. You will find it to be worthwhile reading whether you are a designer, a specifier or a buyer.

All thermoforming processes start by heating the sheet of thermoplastic material to a point that it is soft enough to be reshaped. Positive or negative pressure is then employed to push, pull or stretch the softened sheet into a female or onto a male die that defines the shape of the desired part. The formed sheet is then allowed to cool enough for the plastic to regain enough of its original strength to retain its new shape. Pressure forming is described and illustrated in The Thermo Pressure Forming Process

The use of heat and force to reshape objects had its beginnings in antiquity. The Egyptians thermoformed tortoise shells, horns and hoofs into consumer products. The early colonists heat formed keratin (albuminoid) in the 1700's. John Wesley Hyatt made the first blow molded parts by heating and forcing cellulose nitrate tubes into the first hollow one piece plastic parts in 1867. Three-dimensional relief maps were formed using preprinted thermoplastic sheets in the early 1930's. Acrylic observation domes for military aircraft came into being in the early 1940's. The first blister packages appeared in 1942. The thermoplastic skin packages that are so common today made their debut in.1954.

Thermoforming has continued to grow and is now recognized as one of the primary plastics processing techniques.

Thermoforming's ability to produce relatively large parts with thin walls made it an ideal process for low cost, single use packaging applications. The large volumes associated with the packaging industry allowed packaging per se to become the largest single user of plastic materials. For understandable reasons, the packaging segment of the market has dominated the thermoforming industry ever since the mid-1940's.

In more recent years, plastic material suppliers, machinery builders and sheet producers have turned their attention to industrial thermoforming applications.

Today, there are plastic materials and thermoforming machines specifically tailor-made for these smaller volume but often more demanding industrial applications. The industry is no longer characterized by the thin walled, low cost, flimsy parts that are so typical of thermoforming packaging applications.

All thermoforming processes are utilized to convert flat, basically two-dimensional sheets into larger, more complex three-dimensional shapes by the use of heat and pressure or vacuum.

As product and packaging designers became more familiar with the advantages of the thermoforming process, they asked for increasingly more complex shapes and higher levels of quality. The industry responded with improved materials and more sophisticated forming techniques.

Pressure forming is only one of ten primary thermoforming plastic processing techniques that were created to meet these more demanding requirements of the marketplace.