Pitting on Underside of holes

Cut quality issues can be discussed here, most common issues have been discussed here and should help you.
Post Reply
Charlie10
1.5 Star Member
1.5 Star Member
Posts: 27
Joined: Tue Apr 24, 2018 9:12 am

Pitting on Underside of holes

Post by Charlie10 »

Hole quality is one of the main issues I've been fighting on our new plasma table. The biggest problem is that I keep getting these pits or dimples on the underside of holes. I've gotten it to be less frequent/ pronounced by experimenting with different entry and exit methods, but I haven't gotten rid of it completely. Not very visually appealing.
Holes have also been cutting about .025'' undersize, but not profiles. I've addressed that at the moment by just programming the holes that much larger.
I'm running a Shopsabre Sidekick with a Hypertherm 45XP and fine cut consumables. Enroute 6 toolpathing. Cutting mostly 11 ga steel, .08 and .06 aluminum.
Any help solving this would be appreciated.
plas holes pic.jpg
weldguy
4 Star Elite Contributing Member
4 Star Elite Contributing Member
Posts: 1929
Joined: Fri Apr 17, 2009 11:48 am

Re: Pitting on Underside of holes

Post by weldguy »

What style of lead in are you using?
User avatar
SeanP
4 Star Member
4 Star Member
Posts: 950
Joined: Thu Aug 01, 2013 11:50 am
Location: Co Kerry, Ireland

Re: Pitting on Underside of holes

Post by SeanP »

It's when the slug drops out and the arc is looking for metal, it cant be stopped altogether with leadout/in, the only real way I have found is to have the torch turn off before it reaches the end of the cut, that's possible with sheetcam, sorry not sure about your software.
Powermax XP45
Home built table, Candcnc DTHC 2, Dragoncut 620-4
R-Tech 210 Tig, Jasic 250 mig
Sheetcam, Scanything, Coreldraw
Table build gallery
Charlie10
1.5 Star Member
1.5 Star Member
Posts: 27
Joined: Tue Apr 24, 2018 9:12 am

Re: Pitting on Underside of holes

Post by Charlie10 »

The best luck I've had is arcing in and out on a radius slightly smaller than that of the hole. I've read that you should not have a lead-out on holes and use an overburn, but the pitting has been the worst when I've tried that way.
Thanks. I'm not sure if its possible to turn the torch off before, or how to do so if it is. But I'll look into it.
SSCNC
1/2 Star Member
1/2 Star Member
Posts: 3
Joined: Wed Oct 26, 2011 9:09 am

Re: Pitting on Underside of holes

Post by SSCNC »

Contact our support team, we will be glad to work with you on improving your results.
motoguy
4 Star Elite Contributing Member
4 Star Elite Contributing Member
Posts: 1184
Joined: Tue Aug 25, 2015 12:05 pm
Location: Central MO, USA

Re: Pitting on Underside of holes

Post by motoguy »

I used to arc in/out on holes as well. I found they look much better with perpendicular lead in, no lead out, just a slight overcut (depending on thickness, something like .06 for 3/16), and disable the torch before end of cut (I disable .03 when I have a .06 overcut).
Bulltear 6x12 w/ Proton Z axis & watertable
CommandCNC/Linux w/ Ohmic & HyT options
Hypertherm Powermax 85 w/ machine torch
Solidworks, Coreldraw X7, Inkscape, Sheetcam
FazQuaz
1 Star Member
1 Star Member
Posts: 22
Joined: Tue Apr 18, 2017 11:14 am

Re: Pitting on Underside of holes

Post by FazQuaz »

Motoguy,
How are you disabling the torch before the end of the cut as mentioned above?
CGT80
1 Star Member
1 Star Member
Posts: 20
Joined: Tue Sep 26, 2017 12:25 am

Re: Pitting on Underside of holes

Post by CGT80 »

Tag, as I have the same problem and also use fine cut and sheetcam.
ScottF
1.5 Star Member
1.5 Star Member
Posts: 33
Joined: Wed Nov 29, 2017 10:48 pm
Location: Colorado

Re: Pitting on Underside of holes

Post by ScottF »

In WinCNC you can edit the early off for the torch. I have done this and have been pleased with the results.
I don't have all the answers but I do have a lot of opinions....


ShopSabre Sidekick 8 with water table
Hypertherm Powermax 85 w/machine and hand torches
IR 5hp 60 gal,+ 60 gallons of storage and aftercooler
Lincoln Square Wave 200
14x40 lathe
motoguy
4 Star Elite Contributing Member
4 Star Elite Contributing Member
Posts: 1184
Joined: Tue Aug 25, 2015 12:05 pm
Location: Central MO, USA

Re: Pitting on Underside of holes

Post by motoguy »

FazQuaz wrote:Motoguy,
How are you disabling the torch before the end of the cut as mentioned above?
With CommandCNC (Linux) I create a rule with the M62 P2 (Torch off before end) code. Then I apply it just like any other cut rule.
Bulltear 6x12 w/ Proton Z axis & watertable
CommandCNC/Linux w/ Ohmic & HyT options
Hypertherm Powermax 85 w/ machine torch
Solidworks, Coreldraw X7, Inkscape, Sheetcam
Charlie10
1.5 Star Member
1.5 Star Member
Posts: 27
Joined: Tue Apr 24, 2018 9:12 am

Re: Pitting on Underside of holes

Post by Charlie10 »

plas hole test.jpg
An update on my results and findings. I called the guys at Shopsabre, who have been helpful any time I've had questions. The gentleman there directed me to the early torch-off setting and increased the auto-slow for arcs setting to slow my feed on holes. Turning the torch off early definitely made the difference. On all the lead-in/ lead-out variations I tried I now get practically no pitting. Although I've still had the best results arcing in and making a slight arc out. If I stay right on the hole radius on exit as has been suggested, I still get a slight mark on the edge. The slow for arcs setting is a mixed bag because it made my holes a little more true to size, but it also slows for arcs on the profile of the part. Obviously that causes noticeably more dross and increases run time. That seems like a shortcoming of WinCNC, that you can't slow the feed for only holes. Much happier with my results though, as you can see on the test piece.
Post Reply

Return to “Plasma Cut Quality Forum”