Not cutting through once cut is started- Powermax 125

[fabricator909]

I am having trouble with out Powermax 125 not cutting through material, and getting severe blowback along a cut on higher end of the material thickness for the consumable range (3/8- 65 amp, 1" - 125 amp). The machine will pierce fine, cut the majority of the part, and then out nowhere, stop cutting completely thorugh and start getting blowback, then cut through the material again after several inches. There is no rhythm , and doesn't do it all the time. Attached is a pic of 5/8" cut with 125 consumables.

[jimcolt]

There was no picture attached. Can you provide the cut specs that you used for the 5/8" material? Cut speed, cut height, pierce height, amperage setting, arc voltage? Jim Colt Hypertherm

[fabricator909]

Pics finally attached. The first is 7/8" plate, you can see excellant edge quality until after an 1 after the trun of the corner. The 3/8" plate is the same, good edge quality one side, poor on the other. All cuts are book specs for best quality, we have an air dryer, hypertherm air filter on the machine itself, as well as a filter/ water separator before that. Is this an air pressure issue??

[jimcolt]

So, to rephrase my question about the cutting specs: What amperage and consumable set are you using on each thickness? Can you show a close up picture of the nozzle and shield, so I can see the nozzle bore?

Lower amperage and consumables will provide better cut quality on thinner materials. Varying angularity is caused by a damaged nozzle, which is caused by incorrect pierce height and/or pierce delay time. By looking at the nozzle that was used on these cuts I may be able to offer advice that will solve your issue. Jim Colt Hypertherm

[fabricator909]

Thanks Jim, I'll post pics later of the nozzle. On the 7/8" , 125 amp nozzle. Both the nozzle and electrode were brand new hypertherms. The 3/8" was 65 amp. I have noticed it doesn't matter if the nozzle and electrode are brand new....

[fabricator909]

Thanks Jim, I'll post pics later of the nozzle. On the 7/8" , 125 amp nozzle. Both the nozzle and electrode were brand new hypertherms. The 3/8" was 65 amp. I have noticed it doesn't matter if the nozzle and electrode are brand new. I haven't replaced the swirl ring yet however. I'll check total arc hours on the machine.

[BTA Plasma]

This may sound silly but where is your work clamp connected to? Is it wet? That destroys the works clamp and corrodes with copper in the work clamp by capillarying the water through it. It creates copper oxide and copper sulphate which are not good conductors of electricity.

[fabricator909]

Jim attached are the pics of the nozzles, electrode, and swirl ring.

[fabricator909]

This may sound silly but where is your work clamp connected to? Is it wet? That destroys the works clamp and corrodes with copper in the work clamp by capillarying the water through it. It creates copper oxide and copper sulphate which are not good conductors of electricity.

The work clamp is connected to the slat holder in the water tank, so yes it wet. I moved it directly to the 7/8" plate on the cut shown however, and it made no difference.Also I have a hard time understanding why for example when cutting the 3/8" as in the pic, some parts are cut alright, and then others are not, in the exact same spot! I can HEAR the arc change when the plasma is about to not cut through the material. The air is dry, I just opened the last drop in our air line system, and it was bone dry. This was not the case before the refrigerated air dryer was installed.

[beefy]

Regarding lean/angularity in cuts. Many users have had this issue, myself included. I have a Powermax 1250 and replaced all the consumables yet still I got the lean in one direction. Slowing the feedrate seemed to help a bit.

Anyway, it seems for a few users, that particular issue has been miraculously fixed by replacing the O-ring !!!!! Yep, even though the old O-ring seemed in good nick, changing it out for a fresh one cured their cut lean problems.

That is the one thing I'd never tried, but it will be the first next time I have the lean issue.

[fabricator909]

Thought I had this figured out, and that it was due to a drop in air pressure, however cutting 3/8" today, and the 65 amp consumables did the same thing...

[Cz_apie]

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Also I have a hard time understanding why for example when cutting the 3/8" as in the pic, some parts are cut alright, and then others are not, in the exact same spot! I can HEAR the arc change when the plasma is about to not cut through the material. The air is dry, I just opened the last drop in our air line system, and it was bone dry. This was not the case before the refrigerated air dryer was installed.

Looking at your picture i noticed what you said " In the exact same spot, I can hear the arc change" Well I am thinking that in that exact same spots your cutting line starts running on top of your slats which are running in the same direction as your cuts, causing blow back which stops the moment you start cutting away from your slats again, if that is not the case then try a last resort and this might sound very funny I know, delete those parts cutting incorrect in your design file and replace them with parts from the same file which did cut correct, had a case once where a double cut line were running on top of each other creating all sorts of havoc once it were copied and pasted to other positions in same file

plasma-4.jpg (88.7 KiB) Viewed 1830 times

plasma-4.jpg (88.7 KiB) Viewed 1830 times

Thanks
Deon

[fabricator909]

Spent some time with this issue, I think the biggest cause is electrode wear, cutting 3/4"-1" plate wears the electrode down pretty quickly. Also, another cause, was in sheetcam I think I had it slowing down to much into corners, so it would slow down, and once it jumped back to 100% feedrate, it did so instantly, instead of slow ramp up to 100%. I.E. the plasma arc could not keep up with the jump in feed rate, getting blowback.