Formix Plastics – Process and Material Information
Most plastic materials can be used as raw materials, such as:
- Polyethylenes (HDPE, LDPE, HMWPE)
Important factors in the right selection are:
- Impact resistance
- Service temperature
- Tensile Strength
- Moisture dimensional Stability
- Visual Clarity
- Special requirements (Flame resistance, assemblies, deep draw etc.)
- HDPE is a very tough material with high impact resistance and low cost, but no adhesive sticks to it and painting is only possible with special surface preparations.
- ABS has high impact resistance and excellent dimensional stability, assemblies can be glued together, but the cost is high.
- Polystyrene is inexpensive with good dimensional stability, but impact resistance is low.
Vacuum formed parts are made by heating pre-extruded rigid plastic sheets and forming over or into a mold, applying vacuum to suck the hot sheet to the contour of the mold.
The first step is to setup the machine; mounting the mold, adjusting the rails for the sheets, setting the computer parameters, pre-heating the oven.
The operator than loads the pre-extruded plastic sheet and starts the machine cycle. The machine heats up the sheet for a few seconds up to several minutes, depending on material and thickness. Than the machine pulls the hot sheet over or into the mold, and sucks it to the mold surface by means of vacuum. Now the cooling process starts which takes several minutes. After cooling the operator takes the formed part out, reloads the machine, and inspects the part.
Secondary operations include trimming off excess material, deburring, cleaning and packing. Drilling, milling, riveting, glueing may be added as needed. Most of these operations a done by one of the two robots that we have.
Finally the product goes through final inspection, packing and shipping.