Ratings on plasma cutters?

Typically plasma cutters will cut the thickness they are advertised for, EXCEPT they'll do it very slowly, there will be excessive dross on the bottom of the cut and the kerf may not be straight or even. But it will hack through the material. Those thickness "ratings" are for plain carbon steel under good conditions. I've always planned to DOUBLE the capacity of a machine compared to my everyday work.

I would avoid mail order / imports because of consumables. Generally the consumables are not interchangeable, some have a short life and are expensive. Think of a cell phone. They give you the phone because you buy the minutes. Here they "give" you the plasma cutter because you buy the consumables.

(Hypertherm

I don't know for sure, but I would expect that the overstating varies a lot with manufacturer, imports probably the most optimistic. Just the way these things tend to work. The amperage should be a better rough comparison than thickness rating.

Your comment below makes it sound like they don't rate the duty cycle. If that is true, run away.

I have given up on HF for anything--last time I ordered something I had to wade through magazine sales from the person taking my order.

Steve

snipped-for-privacy@gmail.com wrote:

One thing to consider when comparing plasma cutters is that one manufacturer's 60 amp unit may not cut as well as another manufacturer's even if they do both put out 60 amps. That is because power is measured in watts. Watts = volts * amps. So if one manufacturer's unit can deliver 60 amps at 140V and anothers can only devlier 60 amps at 100V, guess which one will cut better.

I would avoid anything except the major U.S. brands if you are in the U.S. for the simple reason that consumables for the imports might be difficult if not impossible to find, if not now, as soon as the model obsolesces. Parts for U.S. machines, current and obsolete, are generally widely available.

Does anybody have "real" numbers/ratings for speeds on various thicknesses? Seems like we could make a nice database (that should also include other variables/conditions) that people could refer to.

Eg, (I wish I had the tool to actually do the test :-) Miller 1000, 230VAC, 50 amp line, unfiltered Craftsman 6 HP, 30 gallon compressor, no air drier, 50 foot 3/8" air line Handheld, 1/16" standoff

3/4" thick mild steel plate, ...

How about this idea: Plotting/computing rated thickness inches per minute per dollar?

I figure multiply the thickness by the inches per minute (IPM) rating since the thicker the better and the faster the better and then divide by the cost (less expensive is good for me :-).

Eg, Miller 2050 states 0.875" @ 10 IPM, and they run about $2500 at the local welding shop.

Sooo.... 0.875 * 10 / $2500 --> 0.0035 t-IPM/$ Or, $285.71 per thickness-IPM

Perhaps one could add in a duty-cycle rating correction factor or something of the sort as well.

I know that there are likely to be strong variations in the claims by the manufacturers, but it does bring some concrete numbers to bear.

I'm sure a more elaborate and encompassing equation could be employed to give a more accurate representation of the value.

Here's what I've computed for the plasma cutters that I'd love to own but can't afford. Prices are from online sources:

Hypertherm 1000: $2085 @ welders-direct.com 0.75" @ 22 IPM 60A @ 140VDC, 50% duty cycle (240V 1ph) $126 per T-IPM

Hypertherm 1250: $2865 @ welders-direct.com 1" @ 16 IPM 80A @ 150VDC, 50% duty cycle (240V 1ph) $179 per T-IPM

Hypertherm 600: $1650 @ welders-direct.com 0.375" @ 24 IPM 40A @ 140VDC, 50% duty cycle (240V 1ph) $183 per T-IPM

Miller 2050 : $2217 from cyberweld.com Rated cut 7/8" @ 10 IPM 55A @ 110VDC, 50% duty cycle (230V 1ph) $253 per T-IPM

...

Thanks.

-Ralph

Is this a useful number to you? It seems like it would be a pretty specific use situation to make it a useful figure of merit.

If this is useful, a major consideration will be reliability and repair time.

Steve

snipped-for-privacy@gmail.com wrote:

While, it is kind of contrived and strange, it does seem to give some rough approximation of useful kilowatt output (and thus cutting speed/thickness) per $.

Other factors that I would incorporate: duty cycle ratings (multiply) warranty (multiply)

Overall, the Hypertherm numbers seem to be quite a bit higher than others for the same thickness. Either this is magic on their part, or fancy.

Thanks.

-Ralph