How to Select the Right PET Heat Shrink Tubing for Your Application
Selecting the correct PET heat shrink tubing is critical for ensuring reliable insulation in aluminum electrolytic capacitors and cylindrical battery packs. This guide walks you through the key parameters to consider when choosing PET shrink tube for your production line.
1. Inner Diameter (ID) Before Shrinkage
The pre-shrink inner diameter must accommodate your component’s maximum dimension with a slight allowance for easy insertion. For capacitor sleeves, measure the capacitor body diameter and add 10-15% for smooth sleeve fitting.
| Capacitor Size Code | Body Diameter (mm) | Recommended Tube ID (mm) |
|---|---|---|
| 5×11 | 5.0 | 5.5–6.0 |
| 6.3×11 | 6.3 | 7.0–7.5 |
| 8×12 | 8.0 | 8.5–9.0 |
| 10×16 | 10.0 | 10.5–11.5 |
| 13×20 | 13.0 | 14.0–15.0 |
| 16×25 | 16.0 | 17.0–18.5 |
2. Shrink Ratio
PET heat shrink tubing typically offers a 2:1 shrink ratio. This means a tube with 10mm pre-shrink ID will shrink down to approximately 5mm after heating. Higher shrink ratios allow more flexibility in fitting various component sizes with fewer tube SKUs.
3. Wall Thickness
For capacitor applications, thin-wall PET tubing (0.08–0.15mm) is preferred because:
- Thin walls minimize the overall capacitor diameter after sleeving
- PET maintains excellent dielectric strength even at thin walls (>15 kV/mm)
- Thin walls provide better flexibility for automated insertion equipment
4. Shrink Temperature
PET tubing requires a shrink temperature of 150°C or higher. This is higher than PVC (90–110°C) but offers superior thermal stability after shrinkage. PET-shrunk sleeves maintain their shape at continuous operating temperatures up to 130°C, making them ideal for capacitors that generate significant heat.
5. Flame Retardancy
For capacitors used in consumer electronics, automotive, and industrial applications, UL94 V-0 rated PET tubing is essential. Our PET heat shrink tubing meets UL94 V-0 requirements, providing self-extinguishing properties within 10 seconds after flame removal.
6. Color Options
Standard colors for PET capacitor sleeves include:
- Natural (clear) — Most common, allows visual inspection of capacitor markings
- Black — Used for UV protection and aesthetic requirements
- Red, Blue, Green, Yellow — For voltage rating identification or brand coding
- Custom colors — Available for OEM branding requirements
7. Printing & Marking
PET tubing can be custom printed with:
- Brand logos and product identification
- Voltage rating indicators
- Manufacturing date codes
- Warning labels and compliance marks (UL, CE, RoHS)
Conclusion
Choosing the right PET heat shrink tubing involves matching ID, shrink ratio, wall thickness, and flame retardancy to your specific capacitor or battery application. As a specialized manufacturer with 20+ years of experience, Haosheng New Material can provide custom specifications and rapid sampling for your production needs.