The mold designer must consider cavity design when choosing the type of mold steels to use. Some of the things that need to be considered in cavity design are:
- Molding Process
- Type of Plastic
- Number of parts
- Size of the Parts
- Cavity Intricacy
- Fragile Cores
- Sliding Members
- Cooling/Heating Problem Areas
Size of Parts:
Steel choice for small or large parts is greatly affected by the first 3 choices listed above. However if there were no special considerations, lower cost steel choices would be made such as AISI 4140 and 4150. Special considerations with respect to part size would be to use insert choices of H13, S7, D2, stainless steel, or other air and oil hardening tool steels. Nitrated or chrome plated P20 could also be used.
More intricate shaped cavity or cores would also require the use of steel inserts as described for special part size considerations above.
Steel choices used could be carburized or nitrated P20 or air and oil hardened tool steels. The mating material choice could be a hard and wear resistant material of Aluminum/Bronze alloy.
Cooling/Heating Problem Areas:
Sometimes problem areas need to be inserted with Aluminum/Bronze alloy or Beryllium copper because they are better conductors of heat.
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