Page 129 - Module DMV20173

6.0 POLYMER PROCESSING

3. Parts are usually quite uniform in thickness and are formed within a relatively short cycle

time.

Figure 6.13 Blow molding processes.

6.6 THERMOFORMING

Figure 6.14 Thermoforming centre.

1. Thermoforming is a process for forming thermoplastic sheets or films over a mold by

means of the application of heat and pressure.
2. Figure 6.14 shows the equipment for thermoforming process.
3. In this process, a sheet is (a) clamped and heated to the sag point (above the glass-
transition temperature, of the polymer), usually by radiant heating, and (b) forced
against the mold surfaces through the application of a vacuum or air pressure.

4. Fig 6.15 shows the various thermoforming processes for a thermoplastic sheet. These
processes commonly are used in making advertising signs, cookie and candy trays,

BPLK 161 DME 1083