List of DURACON® POM grades

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7. Product Design

7.1 Points in design

• Uniform wall thickness
  Uniform wall thickness solves the problem of uneven mold shrinkage stemming from difference in wall thickness. To eliminate uneven shrinkage due to uneven wall thickness, strive for uniform thickness and make the core as large as possible. Small cores increase heat and cause longer molding cycles.
• Thin wall thickness
  Products should be designed to have thin wall thickness in the range that causes no problem in product functions. Thin wall thickness is advantageous for the molding cycle.
• Symmetrical shape
  Employ symmetrical shape as much as possible to balance mold shrinkage inside product. Uneven mold shrinkage causes deformations of products like warpage. For instance, in the case of product having circumference rib, rib acts as a strut. Since it causes uneven mold shrinkage. In the case of product having deep core inside, large temperature difference occurs between the stationary platen and the movable platen. Since it causes uneven mold shrinkage too.
• Reinforcement by ribs
  Warpage cannot be avoided in some product configurations. In these cases, reinforcement ribs are used to prevent tilt and warpage. Rib thickness is set from 1/3 to 1/2 of product base.