🌊 Webbing / Surface Folds
Causes, Solutions & Prevention in Thermoforming
Wrinkles, folds or webs of excess material. Common around corners and geometry transitions.
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⚠️Root Causes by Category
⚙️ Process
- Sheet too hot — excess material sags
- Uneven heating — hot zones fold
- Pre-stretch timing incorrect
🔲 Mold / Tooling
- Complex geometry — excess material in transitions
📐 Design
- Insufficient draft on vertical walls
✅Solutions & Corrective Actions
Step 1
- Reduce sheet temperature
Step 2
- Add pre-stretch to distribute material
Step 3
- Modify mold — radii at transitions, draft 3°+
Step 4
- Use zoned heating in fold-prone areas
🛠️Step-by-Step Troubleshooting
1
Step 1
Reduce sheet temperature
2
Step 2
Add pre-stretch to distribute material
3
Step 3
Modify mold — radii at transitions, draft 3°+
4
Step 4
Use zoned heating in fold-prone areas
❓Frequently Asked Questions
What causes webbing / surface folds?
Sheet too hot — excess material sags; Uneven heating — hot zones fold; Pre-stretch timing incorrect
How to fix webbing / surface folds?
Reduce sheet temperature
How to prevent webbing / surface folds?
Prevention requires systematic process control: verify sheet temperature, maintain mold vents, ensure proper material drying, and document optimal parameters.
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