What if you cut material thicker than your machine can handle?

[jweaver]

I hope this isn't a stupid quesition.. But say your machine can cut 10mm and you try to cut 16mm.. What happens?

Does it just cut a 10mm deep groove? Does the lack of penetration cause slag to blow out the sides? Or does the heat simply dissipate into the thicker materal and not get hot enough to melt?


Also, can you cut 'bar' with a Plasma? How do you do it? Do you have to rotate around the bar keeping the torch perpendicular to the surface.. Or can you just cut straight across?

Jon

 

[roofman]

I hope this isn't a stupid quesition.. But say your machine can cut 10mm and you try to cut 16mm.. What happens?

Does it just cut a 10mm deep groove? Does the lack of penetration cause slag to blow out the sides? Or does the heat simply dissipate into the thicker materal and not get hot enough to melt?


Also, can you cut 'bar' with a Plasma? How do you do it? Do you have to rotate around the bar keeping the torch perpendicular to the surface.. Or can you just cut straight across?

Jon

I do know iff you cant blow through you will need a bucket of spare tips and nozzels

 

[BrokenBiker]

The machine will be rated for a certain thickness for a clean cut, a larger thickness for a severance cut. Anything greatly over that thicker amount is pointless trying as you will probably get a lot of blowback with the air blowing molten metal out of the cut and straight at your face...

 

[Screwdriver]

A plasma cutter forms a jet of plasma (!) which has to be able to penetrate entirely through the workpiece. Otherwise the molten metal isn't blown away but just piles up until the plasma is extinguished.

S.

 

[baconbarm]

it would probably be just about doable, but you would have to go at such a slow pace it would be impractical. as for cutting bar, do you mean round bar? Plasma cutters perform best when they are perfectly square to the job, they don't like to be twisted and turned, so a cheap 14" chopsaw or burning gear would be better imo for bar, depending on what the circumstances of the job your doing

 

[Jim Davey]

For most plasmas there will be two thickness ratings. First the thickness it can cut effectively at a reasonable pace "Clean Cut" then there is the thickness of metal you can go slowly at maximum power and melt through giving a much poorer cut, this is referred to as "Severance". The problem with severance is that if you go too slowly with the cut you create a lot of heat, oxidising and melting away the edges of the kerf leaving you with an edge that isn't square or particularly straight, requiring lots of post clean up (grinding) kind of defeating the object of a relatively high speed cutting process. So yes, for most sets you can cut a bit thicker than the ratings may say, will the cut be good? Probably not. As for damage, aside from overheating your torch and machine by cutting at max amps for extended periods not really, but you will be burning through tips faster than you would cutting at lower amps and as said if your plasma arc isn't fully piercing the metal and it's got nowhere else to go it will fire molten metal back at the torch destroying consumables even faster. So start from an edge or drill a hole and don't attempt a piercing cut on material thicker than your machines rated maximum clean cut if you want your gear to last.