It is well known that the molds used to create plastic parts ranging from water bottles to automobile bumpers are the most critical – and expensive – part of the injection molding process. In some cases a single mold can cost hundreds of thousands of dollars, not including the ongoing maintenance and running costs.
However, despite being made of hardened steel, the very process of injecting melted resins at high temperatures and pressure into cavities over many cycles begins to wear away and erode the surface of cavities and moving components. Even the thermoplastic material itself can be abrasive or “sticky,” acting like sandpaper or leaving residue that wears down the surface.