Developing Profile Extrusions Dies

• RPVC Pellets 10:1
• RPVC Powder15:1
• High Output PVC Powder 25:1
• LDPE: 15:1
• ABS: 25:1
• Development Technician runs overall profile width to specification
• After measuration, if walls are thin, wire EDM respective wall 50% of final desired thickness. (Polish)
• Appendages short, wire EDM for proper wall thickness first
• If appendages are correct wall but short, wire EDM delta difference
  
  
  Unbalanced Wall Profiles:
  
  Walls/appendages are designed with an “Equal Land Length Ratio”
• Development Tech runs overall profile width to specification
• After measuration, if walls are thin, wire EDM respective walls 50% of final desired thickness (Polish)
• If appendages are short (Flat back die) drop land length
• If appendages are short (SL Die) wire EDM wall
  
  
  Assumptions:
  
• All walls are polished and recast is removed
• Flow diverters are used with diverter thickness added to wire burn
• Profile does not exceed barrel gate adapter
  
  
  Cap-coat Balancing:
  
• Runner is calculated to contain volume equal to, preferably greater than volume to cap-stock surface
• Pre-land area follows the annulus runner. Preferred design should include a tapered descending pre-land.
• Balancing should be done on pre-land by dropping the pre-land depth
• Latest technology suggests secondary pre-land area and two annuli channels
  
  
  Assumptions:
• All channels are symmetrical
• End of annulus channel to be streamlined to prevent stagnation
• Cap-stock thickness is designed into die lip plate over substrate layer
• High viscosity degradable resins and thin cap-coats should utilize 45 degree approach (Male/female)