What is the Difference Between Hot Runner and Cold Runner Molds?

The runner system delivers molten plastic from the injection machine nozzle to the mold cavities. There are two primary types:

Cold Runner Molds:

• Plastic solidifies in the runner channels
• Runners are ejected with parts and must be trimmed
• Lower initial mold cost
• Runner material can be reground (with some quality loss)
• Best for: Low-to-medium volumes, less expensive materials, simple parts

Hot Runner Molds:

• Heated manifold keeps plastic molten
• No runner waste – 100% material efficiency
• Faster cycle times (no runner cooling)
• Better gate control and part quality
• Higher initial mold cost (offset by material savings)
• Best for: High volumes, expensive materials, tight-tolerance parts

We analyze your production volume, material cost, and quality requirements to recommend the optimal runner system for your project.