Quick Answer
The recommended thermoforming temperature for PET sheet is typically 120°C to 160°C for APET and 130°C to 165°C for RPET. The exact temperature depends on sheet thickness, intrinsic viscosity (IV), and mold complexity.
What Is Thermoforming Temperature for PET Sheet?
Thermoforming temperature refers to the heating range at which PET sheet becomes soft enough to be formed without degrading its structure.
Unlike other plastics, PET has a narrow processing window, meaning:
- Too low → incomplete forming
- Too high → material degradation
👉 In summary: PET thermoforming requires precise temperature control within a narrow range.
Recommended Temperature Range for PET Sheet
| PET Type | Temperature Range | Notes |
|---|---|---|
| APET Sheet | 120°C – 160°C | Standard thermoforming |
| RPET Sheet | 130°C – 165°C | Requires higher heat |
| Thick PET Sheet | 140°C – 170°C | Needs more heat penetration |
Why Temperature Control Is Critical
1. Forming Quality
Correct temperature ensures:
- Smooth surface
- Full mold replication
- No defects
👉 In summary: Proper temperature guarantees consistent forming quality.
2. Material Stability
PET is sensitive to overheating:
- Too hot → bubbles, whitening
- Too cold → cracking
👉 In summary: Stability depends on staying within the correct temperature window.
3. Production Efficiency
- Correct temperature → faster cycles
- Incorrect → rework and waste
👉 In summary: Temperature directly impacts production cost and efficiency.
Common Temperature-Related Defects
| Issue | Cause |
|---|---|
| Incomplete forming | Temperature too low |
| Webbing | Temperature too high |
| Bubbles | Overheating or moisture |
| Whitening | Overstretching at wrong temperature |
Key Factors Affecting Temperature
Factory Insight (15 Years Experience)
From real production experience:
- Most forming defects are caused by temperature mismatch, not material quality
- Many buyers focus on price but ignore temperature compatibility
- Stable thermoforming requires coordination between:
- Temperature
- IV
- Thickness
👉 In summary: Temperature control is a system, not a single parameter.
Practical Temperature Setup (Procurement Insight)
When sourcing PET sheet, confirm:
- Recommended forming temp
- Heating consistency
- Thickness tolerance
👉 These affect your actual production cost.
How to Choose the Right Temperature
For Food Packaging:
- 125°C – 155°C
- Focus on clarity and hygiene
For Blister Packaging:
- 130°C – 160°C
- Balance between detail and strength
For Thick Sheet Applications:
- 140°C – 170°C
- Ensure full heat penetration
👉 In summary: Always adjust temperature based on application, not fixed values.
Temperature vs Forming Performance
- Low temperature → easy control but poor forming
- High temperature → better forming but risk defects
👉 Optimal condition:
Uniform heating + correct range + matched material
Common Problems & Causes
| Problem | Cause |
|---|---|
| Webbing | Overheating |
| Poor detail | Low temperature |
| Bubbles | Moisture + overheating |
Pro Tip: Always test temperature + time together, not separately.
FAQ
Q1: Can I use same temperature for all PET sheets?
No. IV, thickness, and formulation vary.
Q2: Why does RPET need higher temperature?
Due to slightly different crystallization behavior.
Q3: How to avoid overheating?
Use staged heating zones.
Q4: What is the ideal thermoforming temperature for PET sheet?
Typically 120°C to 165°C depending on material type and thickness.
Q5: Why does PET sheet form bubbles during thermoforming?
Usually due to overheating or moisture in the material.
Q6: Can PET be thermoformed at low temperature?
It can, but may result in incomplete forming and poor detail.
Q7: Does thicker PET sheet require higher temperature?
Yes, thicker sheets need more heat to soften evenly.
Q8: How do I avoid thermoforming defects in PET sheet?
Control temperature, match IV, and ensure proper heating distribution.
Final Conclusion
Thermoforming temperature is one of the most critical factors in PET sheet processing. Maintaining the correct temperature range based on thickness, IV, and application ensures stable production, high-quality results, and reduced defects.
