... Frequency welding machine for Tarpaulins,Tents,Billboards, Signs,Truck Covers,Canvas,Membrane. Main Application of High Frequency welding ... of large format tarpaulins, tents, shading systems, truck covers, swimming pool covers, airline hangars, billboards, signs, side curtains and many ... be fitted with special curved electrodes for welding round window profiles made of clear PVC and any other shapes ...