Ejector and Drag Marks: T1 Sample Review Checklist

Almost every molded part carries a trace of the ejection system. At T1, the job is not a traceless part. It is separating normal, stable witness marks from defects that signal tool interference, extreme ejection force, or cosmetic failure. Mark depth and location are largely set in tool design. An ambiguous mark you accept at T1 becomes the production standard.

Distinguishing Normal Witness from Tooling Issues

Typical observations: shallow circular marks at pin locations, raised or sunken outlines, linear drag scratches along the pull direction, or gloss circles telegraphing through to the opposite cosmetic face.

Over-force ejection vs. normal witness: Faint pin shadows are inherent. Deep impressions, localized whitening, or push-through gloss on the opposite face mean the part is ejected before it is stiff enough, or that pins are undersized or poorly distributed and need too much force.

Drag lines and interference: Linear scratches along draw usually mean the part is scraping steel. Causes include draft shortfall, texture grip, or a damaged cavity surface. Drag lines are tool wear and stress, not only a cosmetic blemish.

Pin condition: Marks that worsen over time or show localized flash point to worn pins or excess pin-bore clearance.

Cosmetic face placement: Ejector marks on A-surfaces usually mean ejection layout was not reconciled with cosmetic specs. At T1, relocating a pin or switching to a blade or sleeve ejector is still viable, though costly.

Questions to Ask the Molder at T1

Ask which marks the supplier calls inherent to the tool and which they expect to improve with process tuning or polishing. If drag lines are present, ask whether the cause is texture grip, insufficient draft, or surface galling.

Ask whether ejection can be staged, or cooling extended, to cut impression depth, and what that costs in cycle time. If marks land on a declared cosmetic face, ask for the tooling options (pin relocation, polishing) available to fix it.

Evidence and Documentation to Request

Request a marked drawing or photo set mapping every visible mark on the T1 sample back to the tool’s ejection layout. Demand a written classification: “inherent,” “process-tunable,” and “tooling-correctable.”

If cosmetic faces are hit, require confirmation against the zones in your inspection standard. When fixes land, require side-by-side comparisons of post-fix samples against the T1 originals.

When to Withhold Mold Approval

Do not approve tools with drag lines or scratches until the root cause is named. Interference damages tools over time. Hold approval if marks land on A-surfaces with no agreed tooling remedy. Deep impressions with stress whitening or deformation are an ejection-force problem, not a cosmetic one. Fix process or tooling before sign-off. Do not accept “will polish out” without a scheduled, verified polishing step.

Sourcing and RFQ Guidelines

Declare cosmetic faces in the RFQ so ejection layout is designed around them before steel is cut. State that visible-face witness will be reviewed against the cosmetic standard at mold trial. Ask bidders how their tool-design review reconciles ejector placement with defined cosmetic zones.

Disclaimer

PlasticsTechnologyAlliance.com is an independent buyer resource. It does not manufacture parts, design tooling, or certify suppliers. Which marks are inherent and which are correctable depends on the specific tool. Confirm classifications and remedies with your supplier at trial.