Building torch holder for pmx45 questions

[cruzin]

Have a new pmx45 with machine torch and building a plasma table. What is the best method for z axes using the toothed gear on the machine torch. Or do others use a different method to get z axes? Where can one get the gear to use the gear system that is attached to the torch. I read through all the docs that come with the unit and do not find much on it. thanks in advance.

[jimcolt]

There is an industry standard design for mechanized oxy-fuel torches that has been around for 50 years or so. It is a 1-3/8" diameter torch body with a 32 pitch x 1/4" width rack gear. The holder with a pinion gear is available from almost any company that sells mechanized oxy-fuel torches, or anyone that builds cnc machines that use either oxy-fuel or plasma torches. Koike:, victor, Praxair, Airgas a a few suppliers that come to mind.

In reality...very few cnc machines use a manual height setting method for plasma cutting, rather, they use and arc voltage sensing automated height control system that senses the surface of the plate before every cut, automatically sets the torch to the manufacturers pierce height, then when the pierce is complete the torch is rapidly moved to cut height, and once the x -y motion starts the arc voltage feedback adjust the torch height to compensate for variations in the plate. This is critical for good consumable life and good cut quality on a cnc machine.

Jim Colt