Cold runner
- Simpler tool with lower investment
- Runner scrap every shot; regrind rules depend on the resin
- Easy color and material changes
Decision guide
Hot Runner vs Cold Runner Molds: Scrap, Cycle, and Tool Investment
A cold runner is ejected with the part. A hot runner keeps resin molten in a heated manifold. Volume, resin, and color changes usually decide.
Runner systems
Where the runner goes each shot
The glossary and tooling pages explain each system. This page covers the decision.
A cold runner freezes with the part and is trimmed off as scrap or regrind. A hot runner keeps resin molten in a heated manifold so only the part is ejected.
Runner type is set in the tooling scope of the quote when it affects piece price.
Side by side
What each runner changes
Tool investment against scrap and cycle.
Hot runner
- Higher tool investment and heater maintenance
- Little or no runner scrap
- Shorter cycles and more gate options at volume
Routing table
Signals for each runner
Qualitative only.
| Factor | Cold runner tends to fit | Hot runner tends to fit |
|---|---|---|
| Volume | Low to mid volume | High, steady volume |
| Resin | Commodity resin where scrap is tolerable | Engineering resin where scrap adds up |
| Color changes | Frequent changes | Long runs in one color |
| Gate mark | Gate vestige trimmed from the runner | Valve gates can leave a cleaner mark |
Quote inputs
Send this with your CAD
These decide which runner the tooling scope uses.
Resin and whether regrind is allowed
Annual volume and number of colors
Gate location limits on cosmetic faces
Cavitation under consideration
Continue exploring
Related comparisons
Decision guides and the pages that go deeper.
Compare hub
All comparison guides.
Compare hubChina vs domestic tooling
Investment, logistics, and ownership terms.
China vs domestic toolingIn house vs outsourced molding
Capital, staffing, and capacity tradeoffs.
In house vs outsourced moldingHot runner injection molding
Tooling guide for hot runner systems.
Hot runner injection moldingRunner design
DFM rules for runner layout.
Runner designCold runner
Glossary definition.
Cold runnerFAQ
Common questions
Does a hot runner always pay back?
Not always. Scrap and cycle savings have to cover the added tool investment and maintenance, which typically happens at higher volume.
Next step
Quote the runner against your volume and resin
Upload CAD with resin and annual volume. NetProto manufacturing is ISO 9001 certified.