Advanced Thermoforming, 2nd Edition

Chapter 28Production of Flowerpots

Written in cooperation with Thomas Huber, Kiefel GmbH, Germany, Berry Smeulders, Bosch Sprang B.V., The Netherlands, and Noel J. Tessier, CMT Materials, Inc., USA

Most people do not give a flowerpot made of plastic a second look (Figure 28.1). But if you look closer, you might guess the highly developed production process behind it. The flowerpot needs holes in the bottom. The edges need to show “tagslots.” Flowerpots are produced in large quantities. Flowerpots made of plastic have significantly less mass than flowerpots made of clay. This is a considerable advantage in the transport chain and so justifies the application of huge and fast‐running thermoform facilities.

A good example is the flowerpot made of polypropylene. In most cases recycled material is used. During production (extrusion), the PP film is filled with a filler material; in this case it is chalk (whiting). While the whiting does influence the film’s thermoforming behavior, the cost factor requires use of recycled material and filler.

Flowerpot production can be used to demonstrate the superiority of thermoforming. Two‐colored formed parts are produced. This requires using co‐extrusion for the semifinished product. The extrusion process enables the production of film with two differently colored sides. That is why it is possible to have the outside of the flowerpot look like terracotta and the inside dyed black.

28.1 THE THERMOFORMING MACHINE

An automated compressed‐air ...