Frequently Asked Questions

 
 

 

 

What types of material are high frequency weldable?

  These include PVC, vinyl, polyurethane, and all PVC coated fabrics and mesh.
   
 

Are HF welders the same as 'Heat Sealers'?

  No, but similar. A high frequency welder uses high power radio signal, when this is applied to PVC it causes the molecules inside the material to rapidly heat up and bond together. A heat sealer simply uses a heated bar to melt materials together - eg. Polyethylene.
   
  What causes 'Arcing'?
  The most common cause is a dusty working environment, your machine should be kept free from dust - especially the head and bar area. Any black carbon build up must be properly removed, either with thinners or emery cloth. Check the 'Causes of Arcing' section for more info.
  What is the maximum bar size I can use on my machine?
 

Depending on the design of the machine, you can pretty much have any bar shape you want - as long as the total welding surface area does not exceed the power capacity of the machine. There is a simple formula to calculate maximum bar size:-

4 inch (squared) : For each Kw of machine power output

   
  What sort of pens can I use for marking materials?
  You should not use any sort of lead pencil or black marker, as these contain elements that induce arcing.
   
  How do I tune my machine using the power control?
 

As the size of the die has a direct relationship to the power required, adjustments are required for various die sizes. As a general rule, dies with a larger weld area will require a higher power setting.

It is always advisable to utilise the lowest power setting for the first weld, if too high a setting is used, an arc may occur damaging the die. Durring the initial tuning of the machine it is recommended that the weld period be limited to about 3 seconds.

Assuming the die is firmly mounted in its crib and the buffer material is in place, the material to be welded is placed under the die. Once the press comes down the high frequency will be applied to the die. Durring the initial weld the power control can be turned up slowly until the desired 'anode' current is reached. At the end of the weld cycle the work should be inspected and the quality of the weld noted. If there is insufficient bonding, another attempt should be made, increasing the power until a satisfactory weld is produced.

   
  What is a buffer or barrier?
  A barrier material is used between the PVC and the lower platten or work table. This material acts as both an electrical and a thermal insulation. This material MUST span the entire length of the platten or table dirrectly under the die. It must also be firmly attached around the edges with strong packing tape.
   
 

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