Hot Runner Molding: Precise Computer-Controlled Accuracy and Advanced Processes

Hot runner molds are usually connected to needle valve nozzles, which are activated with precise computer-controlled timing for accurate reproduction of parts.

This allows for a number of advanced processes, including: Multi-Cavity Molds – cavities with different geometries and/or volumes; Controlled Volume Balancing – a weld line can be shifted into a non-critical area of the molded part; Stack Molding – multiple parting lines for additional cavities in a given area.

Primary advantages of hot runner molding

• Materials cost savings - no runner to regrind or reprocess
• Least expensive cost / piece
• Reduction of energy costs
• Shorter, faster cycle times - no runners to cool
• Smaller machines - reduced shot volume into runners
• Automated processing – runners do not need de-molding
• Gates at the best position for economical design

Elimination of runners means :

• No runners to remove or regrind
• Reduces the possibility of contamination
• Lower injection pressures
• Lower clamping pressure
  
• Consistent heat within the cavity
  
• Shorter cooling time
  
• Shot size reduced
  
• Cleaner molding process
  
• Eliminates nozzle freeze