[blips]

Hi all. First post here after long time lurking on the forums.

I am planning on making a CNC plasma table and I am in the research phase.

I currently have an old Hypertherm MAX 70, which is in excellent working condition. I am told that the newer Hypertherm machines are of new technology and much more suitable for CNC plasma, but before investing in such a machine, I want to see if I can make due with my old one.

I mostly cut 6 - 10 mm steel with the hand torch (PAC130 I think). I often make flanges with 6 - 9 mm holes which I cannot cut accurately by hand, therefore I have to drill them which is time consuming. Would it be possible for me to achieve this accuracy in a CNC setup with my Max 70, without having to do any finishing touches?

I am told that I can improve my precision by purchasing a machine head torch. Is this true? Would it make sense for me to purchase that instead of a new machine?

Thanks in advance!

[jimcolt]

The Max 70 is an older technology Hypertherm air plasma that uses a high voltage, high frequency pulse to start the plasma process. Newer technology systems use Hypertherms "Blowback" start (all Powermax units). High frequency cannot be used with many of the low cost entry level cnc machines available today.....typically any machine that uses a laptop or a PC as the cnc control will have electrical noise issues when used with a high frequency start plasma.

All 100% duty cycle industrial plasma systems...such as Hypertherms high definition class systems use high frequency start, and likely always will, however these high end plasma systems are used with industrial class cnc machines that use specifically designed cnc controls that operate under electrically noisy conditions.

The Max70 torch if used with a CNC machine will certainly cut with a smoother edge and far better precision as compared to hand cutting. You will not get holes and accuracies with that plasma system that can be compared tpo drilled holes. The Powermax70, which is an air plasma, will produce holes that are tapered, with the bottom of the hole smaller than the top. The quality of the holes will depend on the quality of the motion of the cnc being used, as well as the accuracy of the height control system.

The Max70 hand torch is internally identical to the Max70 machine torch...and cuts the same. The difficualty with a hand torch is with being able to mount the torch perpendicular to the materials being cut.

With a good motion control (cnc machine) that can maintain accurate torch height as well as maintain necessary speed while accurately staying on path will produce fairly nice holes. Attached is a picture of 3/8" (9.5 mm) steel with 5/16", 3/8" and 1/2" holes as plasma cut. The bottom of the holes are approximately .060" smaller than the top. The second and third pictures are of 1/4" steel (6mm) with 1/4", 3/8" and larger holes as cut. The part program was modified so that the bolts fit through the holes (programmed the holes larger at the top)

Jim Colt

Hi all. First post here after long time lurking on the forums.

I am planning on making a CNC plasma table and I am in the research phase.

I currently have an old Hypertherm MAX 70, which is in excellent working condition. I am told that the newer Hypertherm machines are of new technology and much more suitable for CNC plasma, but before investing in such a machine, I want to see if I can make due with my old one.

I mostly cut 6 - 10 mm steel with the hand torch (PAC130 I think). I often make flanges with 6 - 9 mm holes which I cannot cut accurately by hand, therefore I have to drill them which is time consuming. Would it be possible for me to achieve this accuracy in a CNC setup with my Max 70, without having to do any finishing touches?

I am told that I can improve my precision by purchasing a machine head torch. Is this true? Would it make sense for me to purchase that instead of a new machine?

Thanks in advance!