In vacuum forming, maintaining consistent and precise heating of plastic sheets is crucial for achieving uniform forming. Aluminum casting band heaters are often used in this process, particularly for heating thermoforming molds or platens. Here's how they are typically employed:
1. Heating the Mold or Platen
Aluminum casting band heaters are wrapped around or embedded into aluminum molds or platens used in vacuum forming.
The heaters ensure the mold surface reaches and maintains the optimal temperature for forming plastic sheets (usually between 120°C to 200°C, depending on the plastic material).
Even heat distribution prevents warping or uneven stretching of the plastic.
2. Maintaining Consistent Temperature
Vacuum forming requires steady heat to keep the plastic pliable during forming.
Aluminum's high thermal conductivity ensures rapid and uniform heat transfer.
Thermocouples or PID controllers regulate the band heaters to maintain precise temperatures.
3. Faster Cycle Times
Aluminum casting heaters heat up quickly, reducing preheating time and improving production efficiency.
Their durability withstands repeated thermal cycling, common in vacuum forming.
4. Customizable Designs
Band heaters can be custom-shaped to fit complex mold geometries, ensuring even heating across intricate surfaces.
They are often used in clamshell-style vacuum formers where both top and bottom molds need heating.
Advantages Over Other Heaters
- Better Heat Transfer – Aluminum casting provides superior contact with molds compared to mica or ceramic band heaters.
- Energy Efficiency – Reduces heat loss, lowering energy costs.
- Longer Lifespan – Resists oxidation and thermal stress better than other types.
Common Applications in Vacuum Forming
- Thick-gauge forming (automotive parts, industrial enclosures).
- Thin-gauge packaging (blister packs, food trays).
- Composite material forming (ABS, PET, PVC, polycarbonate).
Conclusion
Aluminum casting band heaters are essential in vacuum forming for fast, uniform, and controlled mold heating, ensuring high-quality formed parts with minimal defects. Their efficiency and durability make them a preferred choice for industrial thermoforming applications.
