Archives: March 2014

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  1. What is Injection Molding?

    Injection molding is by far the primary process for converting plastics into useful plastic widgets. Just about all of us touch an injection molded widget every hour of every day. All thermoplastics can be injection molded with a few exceptions like polyimides and PTFE to name a few. Injection molding takes pelletized materials and heats them up to the point...
  2. What is Casting?

    Casting involves introducing a liquefied plastic into a mold and allowing it to solidify. In contrast to molding and extrusion, casting relies on atmospheric pressure to fill the mold rather than using significant force to push the plastic into the mold cavity. Some polymers have a viscosity similar to bread dough even when they are at elevated temperature so they...
  3. What is Extrusion?

    The word extrusion is taken from the Latin word extrudere meaning (ex) out and (trudere) to push. In the extrusion process, a pellet or dry powder plastic is heated and forced through a die. The majority of extrusion is done by screws although ram extrusion is still used for UHMW powder specifically. The screws will melt and mix the material...