Sheet & material defect
Colour streaks & shade variation in thermoforming
Also called: Streaking, off-shade
Colour streaks or shade variation show up as marbling within a part or as a colour mismatch between batches — usually a sheet/extrusion issue rather than a forming one.
Why it happens
- Poorly dispersed masterbatch in the sheet
- Regrind ratio or contamination varying between lots
- Buying sheet from inconsistent outside suppliers
- Colour not matched to a controlled standard
How to fix & prevent it
- Use well-dispersed, controlled colour in extrusion
- Control regrind ratio and keep material clean
- Source sheet from one controlled process
- Match colour to Pantone/RAL with lot control
How Indu prevents it: Because we extrude our own sheet, colour is matched to Pantone/RAL and controlled from the pellet with managed regrind — so shade is consistent within and across production lots.
Troubleshooting help
Fighting colour streaks & shade variation on a part?
Send your drawing, sample or a photo of the issue — our engineers will diagnose the cause and reply with the tooling, material and process fix, usually within 24 hours.
ISO 9001:2015 certified · Most quotes back within 24 hours