Cold runner only
A hot tip does not use this pocket. Open the hot-tip page instead.
Cold slug wells
Cold Slug Wells: Trap the First Frozen Runner Tip
Cold slug wells belong on cold runner tools. Hot tips do not use the same pocket. DFM review comments on gate-region issues after T1 photos if needed.
Design guideline
The well is on the runner, not on the part
A slug well is a pocket at the runner end that accepts the first frozen slug. Poor slug control shows as stringing, drool, or a cold mark at the gate. The well is on the runner, not on the part.
Part geometry rarely shows the well. Fill marks at the gate often trace back to runner-end design. The cold slug defect page owns the mark on the part. Runner design owns layout. DFM review can use T1 gate photos when you have them.
This spoke owns the pocket. Hot tip gates do not use a cold slug well. The design guide hub lists every topic.
Roles
Which page answers which slug question
Stay here for the runner-end pocket. Open a sibling for the defect or the runner.
| Page | Use it for |
|---|---|
| Cold slug wells (this page) | The pocket that traps the first slug |
| Cold slug defect | The mark when a slug reaches the part |
| Runner design | Layout and balance of the runner |
| Cold runner glossary | What a cold runner is |
| Hot tip gates | Heated drops, no slug well |
| Gate types | How the melt enters the cavity |
| Gate location | Where the vestige lands on the part |
| Sub gates | Tunnel gates still sit on a cold runner |
| DFM review | CAD and T1 gate photos |
Checks
What DFM review looks for on slug wells
Qualitative checks. No figure on this page is a NetProto specification.
Not on the part
The well sits on the runner. Do not add a pocket to the molded face.
Gate-region clues
Stringing, drool, or a cold mark at the gate can point back here.
T1 photos help
Share gate-region photos if the first shots already show the mark.
Decision
A clean runner end versus a slug that reaches the gate
Wrong: blame the part when the first frozen tip entered the cavity. Right: fix the runner end.
What goes wrong
- A cold mark at the gate with no runner-end plan
- A slug well modeled on the part face
- Assume a hot tip needs the same pocket
What to try first
- Keep the well on the runner
- Open the defect page if the mark is already on the part
- Use hot-tip gates when the program is on a hot drop
RFQ
Send these notes with CAD for a slug-well review
The quote can start from CAD alone. These notes make the DFM pass specific.
Cold runner or hot runner intent
Gate type and location
T1 photos of stringing or a cold mark, if you have them
Resin family, especially if it strings
Whether a hot tip is an acceptable alternative
Cosmetic faces next to the gate
Related
Related design guidelines
Stay on this spoke for its question. Open a sibling for the neighbor topic or the CAD check.
Cold slug defect
The mark when a slug reaches the part.
Cold slug defectCold runner glossary
What a cold runner is.
Cold runner glossaryDFM review
How NetProto reads gate-region clues.
DFM reviewFAQ
Cold slug wells FAQ
What is a cold slug well?
A pocket at the runner end that traps the first frozen tip so it does not enter the gate. It is runner steel, not part geometry.
Are slug wells visible on the part?
No. If you see a mark, that is the defect, not the well. Open the cold slug defect page.
Do hot runners use slug wells?
Not in the same way. Hot tips keep melt in the drop. Open the hot-tip page.
Can stringing be fixed after T1?
Process and runner-end work can help. Share gate photos. Do not expect a part-face pocket to fix it.
Who sizes the well?
The tooling team. This page does not publish a well size. DFM review comments on CAD and T1 clues.
How is this page different from runner design or the defect page?
This spoke owns the pocket. Runner design owns layout. The defect page owns the mark. DFM review checks CAD.
Next step
Upload CAD for DFM review of the gate region
Share runner intent and any T1 gate photos so review can check slug control before quoting.