Understanding Thermoforming

Abstract

The fi rst edition of this modest work was designed as an introduction and supplement to my larger effort, "Technology of Thermoforming", also published by Hanser. It presented a general overview of this rapidly growing fi eld, without extensive details or equations.Although the basic elements of thermoforming have not changed in the near-decade since the publication of the fi rst edition, the industry is maturing and more details of the inner workings of the process are needed. Thermoforming is not just about machinery, molds, plastics, and making parts. It is also about process monitoring and control, quality assurance, safety and competitiveness with other processes. I've made an effort to broaden the work to include many of these aspects.Two disparate areas for product development have become important recently. Thermoforming has been used in transportation for many years, primarily to produce low-volume parts. Truck and aircraft interiors and bus and train toilet interiors are examples. The development of paint fi lm technology has spurred an interest in thermoformed paint-free exterior panels for domestic vehicles. Another developing area is bio-devices. Biotechnology is arguably the most rapidly growing science worldwide. Of course, there are many thermoforming applications already. A recent development, where 25-micron thick fi lm is thermoformed into 350-micron hemispheres as containers for cell cultures, emphasizes microthermoforming.The intent of the work has not changed. It remains a primer. I've rearranged the chapters to focus on the mechanics of the process fi rst, then to consider the nature of the polymers. I've also added a short chapter on comparing thermoforming -technically and economically -with other technologies such as blow molding, rotational molding, and injection molding.One caveat, though. In the fi rst edition, there were no equations. In this edition, there are equations, but only simple ones, for illustration only.

Arbitrarily Shaped 2.5D Circuits using Stretchable Interconnects Embedded in Thermoplastic Polymers

“…[9] The most practical form of this process for simple shapes is vacuum forming; there the sheet is clamped in an airtight frame at its periphery, and heated up using either a radiative heater (typically quartz infrared heaters) or hot air convection. This is done by heating the thermoplastic material beyond its glass transition temperature where it becomes pliable with minimal force, giving the device its final shape using a mold, and cooling it down to room temperature again.…”

Replication Processes

“…Thermoforming is a well-known replication process for macroscopic dimensions [26,27]. The process is characterized by the forming of thermoplastic polymer foils at elevated temperatures into a three-dimensional shape.…”

A New Method for Estimation and Control of Temperature Profile over a Sheet in Thermoforming Process

“…The thermoforming process is used in a variety of industries like automotive, aerospace, refrigeration and packaging industry [1][2][3][4]. Among the arising manufacturing sectors, the plastic manufacturing industry occupies a strategic place because of the many advantages offered by plastic products.…”