Heating of optical fiber heat shrink tubing

Optical fiber heat shrink tubing, typically made of polyolefin, should be heated to approximately 90–125°C for proper shrinkage.

Recommended Heating Temperature

For polyolefin heat shrink tubing, which is the most common material for optical fiber splice protection, the shrink activation temperature is generally 90–125°C. Applying heat within this range ensures the tubing contracts evenly around the fiber splice, providing moisture resistance, mechanical protection, and maintaining optical performance . Other materials used in specialized tubing have different temperature ranges:

• PVC: 80–105°C, economical but less durable
• PTFE: 327–340°C, highly chemical-resistant
• FEP: 200–230°C, suitable for high-temperature and chemical exposure
• Silicone: 150–200°C, flexible even at extreme temperatures
• Viton: 175–200°C, fuel and chemical resistant

Heating Method

• Heat guns are recommended for consistent, controllable heat output.
• Avoid using open flames, lighters, or soldering irons, as these can overheat or damage the fiber .
• Begin heating from the middle of the tubing and rotate the component to ensure uniform shrinkage.

Additional Considerations

• Many optical fiber heat shrink tubes include hot melt adhesive inside, which melts during heating to form a hermetic seal around the splice .
• Tubing with a high shrink ratio (e.g., 4:1) allows for secure fitting over varying fiber diameters .
• Overheating can crack or deform the tubing, while insufficient heat may leave a loose fit, compromising protection . By following the recommended temperature range and proper heating technique, optical fiber heat shrink tubing can provide reliable mechanical and environmental protection for splices and closures.