Cutting issues.. 16 Gauge steel

[jbirge23]

I am using Premier Plasma 4*8 table with Hypertherm 85 fine cut Hypertherm brand consumables. I am now at a complete loss. This is the 3rd table we have owned however the previous were Langmuir. This table now uses a Proma SD. I am having issues I believe with the Proma settings. I have tried book settings which is not correct for the feed rate. Makes the cuts sloppy looking. The biggest issue is this jagged edge look I have. I can't seem to clean it up. I don't care about the slag I use a bath to clean that if need be. I have tried adjusting the volts from 57-144. The Proma seems to keep the middle light on for 57 so I am assuming that is the correct volts for the table. I have tried adjusting the SPE from 65-90 and the amp of the Hypertherm from 30-45. I can not seem to see improvements that stay. My latest issue is now the head is diving. It will get half way into the cut and lower to the surface of the steel. I am blowing out tips like crazy as well. I can change a tip and it is done in a few minutes I would assume as a result of the diving. I can not seem to keep it consistent. I did cut 10 gauge steel at 82 volts, 60ipm, SPE 65 using a regular cut consumable tip that cut nice. However that the tip was rising instead of diving. I did not keep going with this cut because I am more interested in fixing the 16 gauge issue I am having.

Any help would be greatly appreciated.

[adbuch]

Yes - I agree those are some nasty looking edges. Have you contacted Premier Plasma for their advise on your problem? I cut 16 ga. steel on my Plasmacam table with a Hypertherm Powermax 85 using FineCuts at book settings and achieve fine results. My settings are as follows:

Pierce height - 0.150"
Cut height - 0.060"
Pierce delay - 0.4 seconds
Cut speed - 250 ipm
Current setting - 45 amps

Perhaps try cutting several test pieces using the correct settings and with your height control turned off for comparison.

David

[jbirge23]

This cut is 175 ipm, 39 amps, and 73 volts. It seems the faster the ipm the messier the cut is. The old table I was doing 220 ipm and it was perfect. Everything I have now read was the Premier tables can't handle the higher speeds (I missed this in my research before purchasing.) I have contacted Premier and he helped with the other issues I was having but skates around this issue. I have went thru about 30 fine cut tips in the last 2 months. I will try and turn it off tonight and post the results.

[adbuch]

If your table has heavier components with smaller stepper motors, then you may need to use the Hypertherm cut chart for slow speed fine cut. My table has servos with lighter components and will cut at the regular speeds with no problems. Why did you get rid of your previous table if is was giving nice results?

David

[acourtjester]

Looking at the images for the cuts you have made I think you have more then one issue. It looks like the table is far to flexible in it's movements. I would stop wasting metal and use the pen a paper method to see where and what the movement issues are first. Next is to stop the erratic up/down movement of the torch, as David says turn off the THC. With only the G-code controlling the torch movement and fairly flat metal you should get cleaner cuts. If you do then your last problem is the Proma or its setting. Was the Proma added by you (bought new) or did it come on the table when you bought it??

[weldguy]

I have not worked with the table and thc you are using so I will be of no help with getting your Proma dialed in however one thing I will say is that if your table doesn't like higher speeds that's fine, you just need to find where it likes to operate.

I would suggest doing some dry runs (plasma off) and watch and listen to the gantry, place your hand on it and determine the fastest speed you can go where the motion still feels smooth.

Next step would be to draw a simple straight line 24" long and cut a couple of those with THC OFF and using proper cut height of .060" and find the amperage setting that works well at the speed you determined your machine likes to travel at.

Next step would be to cut a couple of those pieces with your pre-determined speed and amp settings at the correct height of .060" with THC OFF. If you need to tweak the speed down a little for this more detailed cut do so and get it perfectly dialed in.

The next step would be to introduce the Proma THC into them mix to determine the voltage that allows you to maintain the suggested .060" cutting height. Do this step using the 24" straight line cuts I mentioned earlier.

Once you have the voltage determined the Proma may have some smoothing settings to improve upon its performance...I am unsure how Proma operates.

Let us know if you are making progress.

[adbuch]

I agree with Tom and weldguy that it looks like there is more going on here than just a height control problem. Based on those jagged edges, you may have some "rigidity" issues with slop in the mechanical portions of your table. I would recommend checking your belts, gears, etc. for slop or excessive play, and doing as has been suggested - namely using a sharpie pen holder instead of the torch and draw your part to eliminate the plasma torch from the equation while you attempt to trouble shoot your situation.

David

ragged cut.jpg (140.19 KiB) Viewed 5090 times

[Deezl Smoke]

Any updates?
I wonder if the air regulator is having issues?

[weldguy]

No word back from the OP but air reg issues is highly unlikely in this case. It's a THC or motion control issue. Hopefully the OP gets back with an update.

[Deezl Smoke]

Likely so. I was theorizing a bit from my "sewing machine" issues with torch height. Then I recall issues in some of my hydraulic systems where a spring will break in a prv, especially of spool type, and similar characteristics of my sewing machine issue occur.
Looking at the edges in the pictures above, I made a few assumptive theories that possibly pulsing air pressure would blow the torch up and down? Just fun thinking and trying to solve issues. I wish I could help people here more to return some of the help I receive, but since I'm still mostly new to cnc and it is my side hustle, not my main career, I have limits.

[weldguy]

That's great thinking. Never know what kind of problem you can solve or item you can create with that mindset