China factory High Frequency PVC Welding Machine for Tensile Membrane Truck cover Welding Machine Tent Canvas Tarpaulin Welder

What is HF welding?

High Frequency (HF) or Radio Frequency (RF) welding is the joining of materials by supplying HF energy in the form of an electromagnetic field (27.12 MHz) and pressure to the material surfaces to be joined. A generator produces the energy. The tool used to supply the energy is called an electrode. The electrical energy causes the molecules within the material to start moving, which generates heat that causes the material to soften and thereby fuse together. No outside heat is applied. It is instead generated within the material. After cooling the welded surface under maintained pressure, the material is fused and a weld has been created. The weld seam can be at least as strong as the surrounding material – or even stronger.

Four important factors that affect the final weld result are pressure, welding effect, welding time and cooling time. These parameters can be adjusted and combined in different ways to achieve the optimal welding result for a specific material.

The material most commonly used with HF welding is PVC (polyvinyl chloride), sometimes called vinyl and PU (Polyurethane). The material can be thick or thin, reinforced or coated. It can also be plain, coloured or patterned.

NENGPAI INDUSTRY customers manufacture a great variety of end products in these materials, such as truck and boat covers, tarps, tents, structures, pool liners, sunshades, billboards, inflatable products, liquid tanks, film screens, waterbeds, stretch ceilings, valve membranes and oil booms.

Advantages of High Frequency Welding Technology

HF sealing occurs from the inside out by using the material itself as a heat source. The heat is focused at the weld target so that the surrounding material does not have to be super-heated to arrive at a target temperature at the joint.



With HF heat is generated only when the field is energized. Once the generator cycles, the heat is turned off. This allows for greater control over the amount of energy that the material sees over the entire cycle. In addition, HF-generated heat does not radiate off the die like on a heated die. This prevents heat-degredation of the material abutting the weld.



HF tooling is usually run "cold". This means that once the HF is turned off, the material stops being heated, but remains under pressure. In this fashion it is possible to both instantly heat, weld, and cool the material under compression. More control over the weld results in more control over the resulting extrusion, thus increasing the weld strength.



RF welds are "clean" because the only material needed to produce an HF weld is the material itself. There are no adhesives or by-products involved in HF welding.