Plasma on aluminum?

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Any tricks to getting a clean cut? I've been cutting some 3/16" aluminum plate with my Miller 375 extreme. It cuts just fine but the cut edge is really grainy and rough.  Any suggestions?
Reply:Hello AKmud, pictures would be a valuable tool to access the quality of your cuts. Air plasma cutters and aluminum will not equal "clean" cuts as a rule simply because the plasma gas is derived from air. Mixed gas plasmas might cut a little bit cleaner but not anything like the cuts you will see on other materials, whether air or gas mixes are used. So, if you can, include some photos to show what sort of cut quality you are getting and then maybe everyone can give some suggestions. Good luck and best regards, Allanaevald
Reply:My machine was at full power with clean air and a fairly new tip...This is the finished cut I really don't like -
Reply:My miller spectrum 700 cuts aluminum the same way.  Figured I was doing something wrong.Dave J.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Water Blaster is the only way to go for aluminum.......Cheap too......  Miller Dynasty 350Twenty Six HammersThree Crow BarsBig Rock
Reply:I cut a bunch of 3/16" Al with my PM45. All edges needed a quick clean up with the die grinder. Even steel needs to be cleaned up if I intend to tig any of it. I think what you're seeing is normal.Lincoln Precision Tig 185Lincoln Power Mig 256Hypertherm PM 45Everlast 140STSmith O/A
Reply:Still grainy on the edge and needing a shot from the die grinder, but not as ragged as what you have. These cuts were made by dragging the torch across the plate. Not sure what what would happen if the offset was too much.Lincoln Precision Tig 185Lincoln Power Mig 256Hypertherm PM 45Everlast 140STSmith O/A
Reply:My aluminum cuts with my PM 45 look alot more like the OPs than what's above as well.  I clean them up with a file.TA Arcmaster 300CM3XMT 304S22P12 suitcase feederX-Treme 12VSOptima pulserTA161SMaxstar 150STLHypertherm PM45OP setupStihl 020AVP, 039, 066 Magnum
Reply:The 375 extreme will do a decent job on aluminum to about 1/8"....it will be a bit of a ragged, porous cut on thicker sections, such as your 3/16". Not enough power for the thicker materials.Aluminum absorbs the energy (heat) much faster than steel, therefore requires more power. Correct cut speed and adequate power combined with proper cut height will produce a great cut. Here is a pic of as cut 3/16" with a Powermax45 on a PlasmaCam cnc machine at 45 amps.Jim Colt  Hypertherm Originally Posted by AKmudAny tricks to getting a clean cut? I've been cutting some 3/16" aluminum plate with my Miller 375 extreme. It cuts just fine but the cut edge is really grainy and rough.  Any suggestions?
Reply:Originally Posted by Drf255My aluminum cuts with my PM 45 look alot more like the OPs than what's above as well.  I clean them up with a file.
Reply:If you mean abrasive water jet....they cost about 50x the price of an air plasma system, and cut at about 1/5th the speed. great cut quality, but definitely not cheap!An abrasive water jet on a 5 x 10 cutting table sells in the range of $250k to $350k.. An air plasma on an entry level 5 x 10 cutting table sells in the range of $15k to $20k. Cut speed on 3/16" aluminum with the water jet is about 25 inches per minute, with the plasma (at 45 amps) is about 95 ipm.Jim Colt Originally Posted by B_CWater Blaster is the only way to go for aluminum.......Cheap too......
Reply:I think he meant not too spendy to farm out to a shop that has the equipment, Just supply a drawing and have them cut them.
Reply:If the machine costs more, and the part cuts slower.....you simply are going to pay more for the part.....that was the point that I didn't make very clearly!A plasma cut part is always less costly than a water jet part....in this thickness range. Water jet has its advantages in terms of no heat affected zone and nice edge quality, as well as the ability to cut almost anything. It does not have an advantage of productivity or cost per foot of cut when cutting metals.  Hypertherm produces water jets, plasma and laser.....we understand each process quite well!Jim Colt Originally Posted by ironmangqI think he meant not too spendy to farm out to a shop that has the equipment, Just supply a drawing and have them cut them.
Reply:yeah I would like to have a cnc plasma wouldn it be niceMILLERMATIC 212 AUTOSETMILLER BOBCAT 250MILLER DIALARC HFMILLER 15A SPOOLGUNMILLER S32P WIRE FEEDERTHERMAL ARC 186 AC/DCPAKMASTER 100XL PLUS
Reply:Thanks for the replies.  I guess I may just be asking a bit too much out of my small machine... I think I'll whip out the jig saw for the rest of my pieces.
Reply:Originally Posted by AKmud I think I'll whip out the jig saw for the rest of my pieces.
Reply:I have a hard time making these little 3/32" holes with my jig saw...very easy on my PlasmaCam / Hypertherm! This is .08" aluminum that is part of a gas tank baffle. As cut....I made a few dozen of these for a fabricator....I sold them for less than $3 each and shipped them flat rate across the US for less than $9. The customer previously cut them with a saw and drilled the holes at a much higher cost than I could do the work for.Jim Attached ImagesLast edited by jimcolt; 03-12-2013 at 11:01 AM.
Reply:Originally Posted by dallas_ I do wish I could get the plasma to cut a bit cleaner though.
Reply:Agreed. I do need a drag tip. I tend to let the tip get too high from time to time to keep it from touching the material.
Reply:I find that air quality has a lot to do with cut quality. I have, in a pinch, run my plasma right off an air compressor. Messy, with lots of clean up. At my shop, air from the compressor is run through a cooler, self-purging dryer, and a series of filters before going to the plasma. Lincoln Precision Tig 185Lincoln Power Mig 256Hypertherm PM 45Everlast 140STSmith O/A
Reply:Originally Posted by jimcoltI have a hard time making these little 3/32" holes with my jig saw...very easy on my PlasmaCam / Hypertherm! This is .08" aluminum that is part of a gas tank baffle. As cut....I made a few dozen of these for a fabricator....I sold them for less than $3 each and shipped them flat rate across the US for less than $9. The customer previously cut them with a saw and drilled the holes at a much higher cost than I could do the work for.Jim
Reply:You may want to read this article http://www.thefabricator.com/article...tting-aluminumPlasmaCam CNC cutterLathe and Band SawClamps