T0 sampling: first shots to approval

T0 (first sample) is the first time the new tool runs on the press. The goal is to see fill balance, catch flash or short-shot risk, and check critical dimensions. The part is not series-approved yet — process tweaks and small tool adjustments are expected.

First trials set drying, temperature profile, injection pressure and cooling from the resin datasheet. Gate size, flow length and shot weight are logged. Each shot is numbered; color, surface and dimensional differences are photographed.

Critical dims are checked with calipers, micrometers or height gauges. Shrink and warpage are compared to CAD. If needed, spotting, ejector or cooling tweaks are made, then T1 or a revised T0 is run.

An approved T0 sample becomes the reference for series parameters. After customer sign-off, a process card is locked; lot tracking and quality criteria follow that sample.

T0 checklist

• Resin drying and press heat profile
• First shots: fill, air traps, short / flash
• Part weight and cycle-time log
• Critical dims (including shrink)
• Surface quality and color uniformity
• Tool / process revision if needed
• Approved T0 and process card