How to Select the Appropriate Hot Air Welding Machine Parameters Based on the Thickness of PVC Coated Fabric？

PVC Coated Fabric and Hot Air Welding Technology

PVC coated fabric is a composite material widely used in fields such as tarpaulins, advertising banners, and waterproof membranes.  Its base layer is usually polyester fiber fabric, coated with a polyvinyl chloride (PVC) layer. Hot air welding is a technology that uses high-temperature hot air to melt the surface of the material and then applies pressure to bond it. The weld strength can reach more than 85% of the base material, and it also has good sealing and durability. Compared with adhesive bonding, hot air welding is more suitable for large-scale projects (such as projects over 5000㎡), effectively avoiding problems such as incomplete welding and leakage.

Selecting Core Welding Machine Parameters Based on Thickness

1. Power and Thickness Matching

The power of the welding machine directly determines the range of material thickness it can handle: Thin materials (≤1.0mm): such as advertising banners and lightweight tarpaulins, a lightweight welding machine with a power of 800~1500W can be selected. For example, a domestic 850W model is suitable for thicknesses of 0.15~1.0mm, with a price of approximately 4000~5000 CNY.

Thick materials (1.0~3.0mm): such as geomembranes and heavy-duty tarpaulins, require a high-power model of 1600~3000W. For example, a 1600W welding machine can handle single-layer film thicknesses of 1~3mm, with a price of approximately 7000~8000 yuan.

Ultra-thick materials (>3mm): require professional equipment above 3000W, such as the LEISTER UNIPLAN E model (2300W) which supports a high-temperature output of 620℃, suitable for thickened PVC rolls.

2. Coordinated Adjustment of Temperature and Speed

Temperature and welding speed need to be dynamically adjusted according to the thickness to avoid overheating or incomplete welding: Temperature setting: generally controlled at 250~450℃. For thin materials (<1mm), low to medium temperatures (250-350℃) are recommended, while thick materials (>1.5mm) require high temperatures (350-450℃) to ensure complete penetration.

Welding speed: Thin materials can use faster speeds (3-7m/min), while thick materials require slower speeds (0.5-3m/min) to extend the heat application time.

When welding 2mm thick PVC waterproof membranes, the temperature can be set to 400℃ and the speed to 1.5m/min, with added weights to increase pressure.

3. Pressure and Accessory Adjustment

Welding pressure: Thick materials require additional weights (such as the gravity adjustment module included with the welding machine) to apply even pressure through the pressure roller, preventing incomplete welds.

Welding nozzle and pressure roller: Dual-drive pressure rollers are suitable for uphill or vertical welding, and diamond-toothed pressure rollers prevent deviation; wide welding nozzles (such as 20mm welds) are suitable for thick materials, improving tear resistance.

Conclusion

The welding quality of PVC-coated fabrics highly depends on the matching of equipment parameters and material thickness. By scientifically configuring power, temperature, speed, and pressure, and selecting the appropriate machine model based on the engineering scenario, not only can the weld strength and impermeability be improved, but construction costs can also be significantly reduced. It is recommended to conduct small sample tests before formal operation to optimize parameter combinations.