Help With Fine Cut Slow Speed 16 gauge??

[lelyea]

I am new to plasma in general. Recently purchased an ArcLight Pro 4 x 4 table with DTHC and a PowerMax 65. Using SheetCam and Mach 3.

I will attach two or three pics of my problems - which are; DEEP DIVOTS on backside of cuts at lead-in locations, DEEP dross on backside. I have read many posts and burned up a 4 x 8 sheet of 16 gauge steel experimenting. I've learned a lot - but not enough. I've verified my consumables and switch them out with new ones. Air is dry as a bone. No open paths on drawing.

Cuts in pics were done with the following settings:
amps: 40 (I've tried 45), pre-set volts: 80, inches per minute: 130 (I've played), None clicked on "Loop sharp corners", no lead out, no overcut,
tool is T90 - finecut low speed 16g steel
INSIDE CUTS: lead-in: Perpendicular, length 0.07 in (I've played), inside offset,
OUTSIDE CUTS: outside offset, reverse cut direction, lead-in perpendicular, length 0.07 in.

Could REALLY use a little help. (The hole in the 'hole' pic is a slot for a light switch plate, for size reference.)

Thanks, Len

[img][http://caps.ncmich.edu/len/divot.jpg]
[img][http://caps.ncmich.edu/len/dross.jpg]
[img][http://caps.ncmich.edu/len/hole.jpg]

[gamble]

I don't really do 16gauge, but I do a lot of 14. At 14gauge i cut at 150IPM and about 28 amps. So 16gauge if it were me I'd guess I would put my machine at 24-25 amps and 150IPM (unless your machine can cut faster which it probably can)
Here is a cut charge for the powermax 30 (from what I found on a quick google search the 65 didn't have material this thin)


So this says 30 amps at 175IPM

[lelyea]

Thanks for the reply. I don't think it is applicable though . . . My PM-65 uses 40-45 amp fine cut consumables. There is a chart in my HT book - just not quite getting there with them.

Thanks

[gamble]

My 45 uses 45amp consumables and still cuts well at 25amps. Try it

[jimcolt]

I'd be happy to help you get dialed in. Can you repost the pics so they can be opened...or send them to me directly at jim.colt@hypertherm.com

- Dross is caused by cutting too slow or with too much height...or a combination of both.
- Arc voltage listing in the Hypertherm manual will provide you with close to the correct height, however every height control will have different levels of calibration....so you must adjust the preset voltage to ensure the torch is maintaining the correct cut height.
- I find that the cut heights listed for the Finecut consumables are slightly too low. Shoot for about .075" to .080" off the material and use the 220948 shield.
-Divots at the pierce point are caused by having too much of a pierce delay time at the beginning of the cut (pierce). You can use longer lead ins, or you can minimize or eliminate the pierce delay time on thin materials. Pierce delay is to allow the torch to fully pierce the material before any x, y or z movement occurs. Different machines have different internal delays.....so the suggested pierce times in the Hypertherm cut charts may need to be adjusted (usually shortened) for your machine.

Jim Colt Hypertherm

[whiskeymike]

If you can post the pictures, that would helpful as Jim mentioned. Are you using the finecut shielded consumables as shown on page 3-14 of the manual? (Manual can be found here... https://www.hypertherm.com/Xnet/library ... format=pdf - Jim, fyi, the link from the 65 product page for operator manual is broken. Had to search for it manually. Might want to mention it to your IT folks)

If your table doesn't flex/wobble, I'd give up the fine cut low speed tools and cut charts, as that's what I understand they are for. I just got my table a couple weeks ago and had a lot of problems using that preconfigured tool, specifically the fine low speed cuts with 16ga. I made my own tool from the cut charts in the manual on page 3-39. I used everything exactly as it is in the book, except I cut back speed by 10% by recommendation of Luke at CandCNC and it works perfectly for me. I have the charts up, so I'll list them out in case it's helpful. Amps - 45 Amp, Torch to work distance - .06, Initial Pierce Height - .15, Pierce time delay - .04, Speed 250(I reduced to 225 and it cuts nearly dross free), and Volts 78. I thought the Kerf chart was confusing, but it says that mild steel for fine cut is 14 Ga - 0.043 and 18 Ga - 0.049, with nothing listed for 16. I split the difference and am currently using 0.46 and it seems fine.

FYI, I don't have an Arclight. I have a Bulltear 4x8, but I think Arclight uses CandCNC as my table does. I also use a HT 65 with the mechanized 45 amp fine cut consumables.

Good luck. At certain points it's really frustrating. But each cut you gain a bit more insight and get the hang of it. If you are using a large test piece, I would cut it down to a small 2x2 square or rudimentary shape that is repeatable. Each cut I took a sharpie and noted what I changed and then later was able to see the progression of more/less dross, cut angle, pierce holes, etc... it was educational. I used about a half sheet of the 16 gauge to get it dialed in. I'm still having a bit of messy edges on small holes, but I'm working on putting them in a different layer and adjusting the settings specific to those holes.

[lelyea]

First - thanks to everyone.

I am using the FineCut shielded consumables on page 3-14 (220948 shield, 220930 nozzle and the 220854 retaining cap). Looking at the page it says to use the 220953 retaining cap. Is that a problem? Am I using the wrong cap? I ordered the FineCut kit and thought since they didn't send the cap the one I had would be fine - plus everything seems to fit.

Guess I don't get how to do a picture link - I tried. The links to the pictures do work - you just have to copy and paste them. I will try the pictures again . . .

No wobble on the table. I don't think it would wobble or vibrate without the 200 lbs of water, but certainly not with it.

Yes, table uses CandCNC.

Settings for my finecut low speed 16g steel follow:
kerf width = 0.026 in, feed rate = 130 ipm, pierce delay = 0 sec, pierce height = 0.09 in, plunge rate = 150 ipm, cut height = 0.05 in, pause at end of cut = 0 sec, preset volts = 80, dthc delay sec = 2, tip size - amps = 45, no dthc - 0 = 1, leadin type = normal. In the job I have been changing the feed rate to 140 ipm.

Another try on the pictures. Hehehe . . . Believe I got it on the pictures. I hovered my cursor over the button and it showed me the format. I laughed at myself . . . Believe it or not I am an IT/Network/Internet executive with 25 years of experience (I should have figured it out the first time!!).





Thanks again.

Len

[lelyea]

I tried WhiskeyMike's settings - still using FineCut consumables. MUCH less dross. Less of a divot on the back too, and almost nil on the front - but still a significant divot. I reduced the pierce delay to zero - and still . . . Then, I get a chop on the two ends of the piece, but not on the sides . . . What is that about?? Pictures below are both of the backside.

[whiskeymike]

What is your voltage divider set at on your PWM? My HT was set at 50:1 and my PWM was set at the default of 7:1 and I was getting nasty cuts and weird cut heights. I assume the two were correlated as when I changed the jumper to be 50:1 to match the HT, everything cleared up. You might check that., although I'm running ohmic, not sure if you are. Those cuts are pretty ugly. Seem really hot.

[lelyea]

PWM is 50:1 and without taking the cover off my HT I am assuming it is set at the default 50:1 from the factory.

[gamble]

The last pic you posted. Is that supposed to be wavy or straight? If it's supposed to be straight check your bearings

[lelyea]

Cut is supposed to be straight. This is NEW - just since changing settings - my first post here. At work - will check bearings when I get home. What is really strange is this morning did one more cut (same part as pictured) and three sides smooth and one side wavy . . .

[michmetalman]

I have a PM 45 and the fine cut consumables cut worse then the regular 45 amp. I don't even like using them. I just dial it down to around 27 amps and it cuts awesome.

[jimcolt]

There are no Finecut consumables available for a Powermax45. You likely are using the T30 , 30 amp consumables. If you use these and follow the specs in the T30 cut chart in your Powermax45 operators manual they will provide decent cutting results on thinner materials. These consumables, as well as the Finecuts (as used on other Hypertherm systems) require very good height control....or they will not provide the advertised cut quality or life.

Jim Colt Hypertherm

I have a PM 45 and the fine cut consumables cut worse then the regular 45 amp. I don't even like using them. I just dial it down to around 27 amps and it cuts awesome.

[Bigdogbro1]

I use T30v consumables on my T45v torch head all the time and get great results on 16ga CR steel.

https://www.youtube.com/watch?v=DCGO1P2gQUY

[davek0974]

The last pic you posted. Is that supposed to be wavy or straight? If it's supposed to be straight check your bearings

Also do a cut with the THC turned off - that ugly wavy cut might be caused by the THC making the torch "saw-tooth" instead keeping steady.

[davek0974]

T30 consumables on a PM45 @ 30A - 1.2mm stainless

I was impressed

[Owen]

The last pic you posted. Is that supposed to be wavy or straight? If it's supposed to be straight check your bearings

Also do a cut with the THC turned off - that ugly wavy cut might be caused by the THC making the torch "saw-tooth" instead keeping steady.

This is good advice. I recently posted a thread having issues with "saw tooth" and it turned out my THC rate was completely off. What is your THC rate set at?

It was also suggested to me to change my "Span Volts" setting to a higher number (5/4) when using fine cuts. This setting can be found in your cut profile in Mach3, near the THC rate setting.

The one thing that this forum has definitely taught me is - the lower the amperage and speed, the cleaner the cut. Even though you have a 45amp fine cut consumable, they cut great at way lower amps. For 16 gauge I've recently been cutting at 30amps, and am going to dial that down a little bit more.

[jhsenterprises]

Ok, so I'll start by saying, yes I'm new at this.... Got my bulltear up and running. First thing we cut were some brackets out of 10 gauge, using the stock consumables that came with the hypertherm 85 and selecting the tools for 10 gauge mild steel, the cuts were pretty good. I really wanted to try out the fine cut consumables though. So I bought the nozzle and the different shield. Changed them out last night and did a test cut. I selected the fine cut low speed 14g steel. I set dial on my hypertherm 85 to 45 amps, didn't change anything else. The cuts were horrible. I'm picking up a 4x8 sheet of 14 gauge mild steel tonight and want to try it again. But was hoping I could get some advice and what I'm doing wrong. Should I be mucking with air pressure? I've got it set to the recommended 130 psi going into the hypertherm. I'm also using a 4 stage air/particle separate so I know I've got good clean dry air. When changing nozzles and material sizes what do I need to manually set on the hypertherm that isn't getting set via the software?

[jhsenterprises]

So I think it was just the crappy material I was trying to use. It's a weird size. I got a fresh sheet 4x8 of 14 gauge and selected the toolset for it and it cut out great.

[tcaudle]

Included in the pierce delay is the plunge time that it takes to move from pierce height to cut height. That gets set in SheetCAM so its not part of a tool setting That rate should be above 60 IPM.
NO pierce delay on 16Ga . .070 is not a long enough lead-in That is not much longer than the kerf width. Use as long a lead-in as will fit the cuts because the machine needs time to get up to speed to make good cuts.

If its any consolation you are starting out trying to cut the hardest thing first. The thinner the material the faster you have to cut, The faster you have to cut the less tolerance there is for the cut parameters and the higher the inertia of the gantry . Fine cuts are harder to get a perfect cut than regular consumables and less forgiving of any mistakes.

[jimcolt]

Also, as I have posted many times: When cutting these three thicknesses, 14, 12 and 10 gauge with Fine cut consumables....if you get an ugly cut that sometimes does not fully penetrate....stay with the book specs except increase the arc voltage so that the steady state cut height increases from the "book" recommendation of .060"....to about .075". These thicknesses seem to have more internal chemistry variations (different levels of manganese, carbon, silicon probably) and require a higher arc voltage to cut with best quality. Thinner materials (below 14 ga) seem to cut best at the recommended height of .060". Jim Colt Hypertherm

[Bobkovacs]

I'm glad I'm not the only one getting less than stellar results on 14ga with the finecuts- I've got my settings for standard consumables pretty well dialed in, and every time I think "let's give the finecuts another try", I'm sorely disappointed (lack of cut through being the biggest issue). I may give them one more try with the added info above.

[motoguy]

I'm glad I'm not the only one getting less than stellar results on 14ga with the finecuts- I've got my settings for standard consumables pretty well dialed in, and every time I think "let's give the finecuts another try", I'm sorely disappointed (lack of cut through being the biggest issue). I may give them one more try with the added info above.

10% slowdown (and corresponding voltage increase, 200ipm/88v on 14ga) and 075 cut height solved this issue for me.

[Bobkovacs]

10% slowdown (and corresponding voltage increase, 200ipm/88v on 14ga) and 075 cut height solved this issue for me.

Interesting- I would have figured a higher cut height would make the cut-through problem worse. I'll give that a try