I'm looking for a post with cut quality

[DanOSB]

someone recently posted a image with all problems with the cut quality

if the torch is too low it will have that cut quality and if torch is too high there will be dross on the botom of metal and there was a quite bit info in that and i cant find that post now..

hope someone knows what im talking about i saw it last week or something.. and i have been looking all over today and cant seem to find it..

Cheers
Dan

[Lasercase]

someone recently posted a image with all problems with the cut quality

if the torch is too low it will have that cut quality and if torch is too high there will be dross on the botom of metal and there was a quite bit info in that and i cant find that post now..

hope someone knows what im talking about i saw it last week or something.. and i have been looking all over today and cant seem to find it..

Cheers
Dan

I assume you're talking about laser?
Ask me any question I am happy to answer.

Case

[DanOSB]

no im looking for the post for plasma cutter (i use plasma not laser..

thanks lasercase

[jgramlich]

THC Question

DIY torch height control


You might try those two. There have been several posts lastly about THC (torch height control) that have had a lot of discussion about cut quality...it's probably in there.

[DanOSB]

i already looked those two posts..

just a black n white picture with 10 different cuts on side view of a metal and explaining why the cut quality isnt good.. the solutions ie: torch is too high or torch is too low or cutting counter clockwise not clockwise why there is more bevel on one side compared to other etc...

i wished i actually saved that image the first time i saw this..

[DanOSB]

i found one picture that is very simlar to one i was looking for.. but the one i saw before had more details (dross location and amount of dross and more solution to get better cut quality.. hope someone else knows what im talking about..

Cheers
Dan

[jgramlich]

Ah, I know what you're talking about but I don't think I've seen that particular post. I'm interested in that as well. :-)

I did find a pretty cool little video over at Hypertherm's web site not too long ago...there's a link right on their front page called Consumables: Care and Optimization. It's mostly about how to take care of your parts, but there were some explanations of cut quality in the video as well.

[jimcolt]

If you let me know more detail about what you are looking for...I'm sure I can help you find it. Hypertherm has tons of plasma process troubleshooting information. Hypertherm tech service has some posters with process troubleshooting info/suggestions......and I could send you presentations about various aspects of plasma cutting...from a technical perspective.

Let me know what you are looking for.

Jim

[lowpull]

It would be nice if someone who has the sweet spot dialed in could do a quick pattern of test cuts, but vary one of the variables each iteration and then take pictures. Because I sure cant get dross free cuts on 12 gauge HR. But I dont know which variable I need to change. Amperage , height , speed ????

[jimcolt]

I don't know what you have for plasma....but if you cannot get dross free cuts on 12 ga....something is definitely wrong!

Amps.....look in the operators manual for your plasma....find the cut charts, findd the material thickness you want to cut. If there are choices of differnt consumables and power levels....choose the lower power levels for best edge quality, higher for best speed. If you choose a 40 amp process, put all of the parts as listed in the manual in the torch and set amps at 40 amps.....no more, no less. Lower than 40 amps through a 40 amp nozzle softens the arc by reducing energy density. More than 40 amps increases energy density, but will dramatically shorten nozzle life....which is indicated by dross and poor angularity.

Cut speed. If the book says to cut at 100ipm at 40 amps at 1/16" torch to work distance....try it. If there is dross....increase speed 5 ipm at a time....the dross eventually will go away (assuming the consumables are good...and everything else is working as designed).....keep going faster and faster.....and the dross will come back.This is called high speed dross (hard to remove), the slow speed where dross just disappears is called low speed dross (easy to remove)....the in between speed range is called the DFZ (dross free zone). Better plasma systems have wider dross free zones. The lower end of the dross free zone produces the best edge angularity.....many slow down until the easy to remove low speed dross forms....as lower speeds produce better edge smoothness and angularity...and the dross removes easily.

Torch height. Follow manufacturer recomendations....they designed the torch, they know where it cuts best (I'm speaking as a long term Hypertherm employee). It is very important on all materials thicker than 3/16" to pierce at a height that is 1.5 to 2 times the recomended cut height....then index down quickly to the cut height. If you ignore this rule....you will ruin the nozzle orifice on the first pierce.....and you will have varying cut angularity and dross.

Hope this helps!

Jim

[jgramlich]

One thing I got out of that video I posted above is the shape/direction of the arc beneath the plate. When the torch is cutting near the edge of a plate grab a piece of dark glass/faceshield and watch what it looks like below the cut. If the plasma arc is coming straight down out of the plate, you're going too slow. I believe it should be something like 15-20 degrees behind the cut. If it's around the 45 degree range, you're going too fast. That's a good eyeballing method for determining if you're cutting at the correct speed.