Forming defect
Wall thinning in thermoforming
Also called: Thin walls, uneven wall thickness
As a sheet forms, its fixed volume of material stretches over a larger surface; the deeper the draw, the thinner the walls. Excessive or uneven thinning leaves weak corners and thin sidewalls that can fail in service.
Why it happens
- Deep draw ratio with no material pre-stretch
- No plug assist to redistribute material into the walls
- Uneven sheet heating leaving hot spots that thin first
- Sharp corners that concentrate stretching
How to fix & prevent it
- Add a plug assist to carry material into the walls and base
- Use billow/pre-blow to pre-stretch the sheet evenly
- Balance zoned heating for a uniform starting temperature
- Increase corner radii and reduce draw ratio where possible
- Start from a thicker gauge sheet for very deep parts
How Indu prevents it: We model wall-thickness distribution during DFM, then use plug assists and pre-blow on our own lines to keep walls uniform — and because we extrude the sheet, we can start from exactly the right gauge.
Troubleshooting help
Fighting wall thinning 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.
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