Fixing Shrink Quality Problems in Tunnel Heaters
The shrink tunnel finalizes the package appearance and tightness:
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Incomplete Shrinking/Wrinkles: Caused by insufficient tunnel temperature, too short dwell time (conveyor speed too fast), poor air circulation (fan failure, clogged ducts/filters), or incorrect/poor-quality shrink film. Solution: Increase tunnel temperature, reduce conveyor speed to increase dwell time, check fans, clean ducts/filters, use appropriate shrink film.
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Product Distortion/Burning: Results from excessive tunnel temperature, too long dwell time (conveyor too slow), or heat-sensitive products. Solution: Reduce tunnel temperature, increase conveyor speed, use low-temperature shrink film, add protective pads between product and film, or lower temperature within product tolerance.
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Hazing/Crystallization on Film: Caused by excessive heat or dwell time leading to film over-shrinking/degradation, or inherently poor film quality. Solution: Lower temperature or increase speed, replace with higher quality shrink film.
Essential Monitoring: Shrink quality is highly sensitive to temperature/speed balance and airflow. Monitor exit temperature and visually inspect packages frequently. Keep tunnel filters clean.
