Problem:
A customer utilized polypropylene-based, glass reinforced structural plastic in automobile front-ends and parts, power mower shrouds, snow shovels and guitar cases. This glass-reinforced polypropylene had a critical softening temperature, and could be stamped with metal-forming equipment already in the plant. Therefore, the process required a low facilities investment, but a method of heating the plastic sheet was needed.
Solution:
Watlow's Raymax 1120 panel type radiant heaters were used to preheat the plastic sheet material, which was then conveyed to a die where the final configuration was formed.
Originally, the customer purchased a competitor's radiant heater with quartz tubes. Their uneven heating caused some of the plastic to burn. The irregular heat also caused the material to have a high surface temperature and cool inner temperature resulting in poor stamping.
The Watlow Raymax 1120 radiant heater, operating at a lower temperature than quartz tubes, emitted a greater percentage of infrared energy, with minimal wavelength, for penetrating the plastic material. The heater met the need for even temperature and even penetration, and three zones in the radiant oven enabled rapid processing. Watlow specified and designed the complete system within two weeks.
