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Fine cut problem

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waldner33
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Fine cut problem

Postby waldner33 » Mon Apr 16, 2018 10:07 pm

I use ezgcode creator , I select my 14 ga fine cut and when I check all the settings they are like the hypertherm book , with the hand held pendant I load 14 ga fine cut , preloaded hyperterm parameters , the powermax is set at 45a, when it cuts like around the jagged edges it works but when comes to a straiter line and speeds up it don’t cut so nice so what am I doing wrong ? Ezcut cnc 5x12 ,it cuts nice with 45/65/85 shielded , works good just can’t get fine cut to work , and auto hight works , would it help to turn it down to 40 a and run slower? Any advice would be great .

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Re: Fine cut problem

Postby jason.jason.p » Tue Apr 17, 2018 11:20 am

Try 40A @ 120imp thats what I run most often. Only because the THC I have cant keep up with 240 feedrate. still it works good for me very little dross

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Re: Fine cut problem

Postby motoguy » Tue Apr 17, 2018 10:40 pm

I run 200ipm, 45a, 88-90v. That's roughly 10% less than finecut book specs. I run into the same issue as you at book specs. I've tried running book speeds with increased cut height (.075-.080), and it still does it.

I'm considering getting away from Finecut altogether due to this issue. Running slower/higher than book completely negates the benefit of Finecut (decreased kerf) for me anyway, so it doesn't really make sense to run them over the standard 45A consumable.
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waldner33
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Re: Fine cut problem

Postby waldner33 » Wed Apr 18, 2018 2:19 am

I’ll give that a try guys thanks

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Re: Fine cut problem

Postby rickjamesbish » Thu May 31, 2018 7:20 pm

Ok.. I was about to order the Duramax Lead for my Powermax 45 but based off this I am reconsidering. My PlasmaCam table is a DHC2 but its base. I have not HC, no software upgrade, etc.. Is the fine cut option going to be more trouble than its worth ?
Last edited by rickjamesbish on Fri Jun 01, 2018 10:32 am, edited 1 time in total.

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Re: Fine cut problem

Postby steelfx » Fri Jun 01, 2018 7:04 am

I use mostly fine-cut nozzles, all the way up to and including 3/16" thick MS. If the design you're cutting has a lot of interior detail, fine-cut is the ONLY way to go. Fine-cut is just the nozzle...all the other consumable parts are the same. I cut 14AWG MS at 120 IPM, 78V, 45A, Pierce height of 0.090" and cut height of 0.060". Very little dross and the cuts are beautiful. And, I almost forgot..I cut Shielded. Un-shielded puts the nozzle tip in harm's way.
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Re: Fine cut problem

Postby steelfx » Fri Jun 01, 2018 7:18 am

Regarding Hypertherm Cut Charts. I've found (in Most Cases), if I throttle down the IPM by 20%, the cuts are just right. On thick steel, I'll back off my IPM by up to 45-50%, less if I'm using an 85Amp Nozzle.
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Re: Fine cut problem

Postby jimcolt » Fri Jun 01, 2018 8:29 am

I run at book speeds, sometimes faster if there is dross with my Powermax 45, 45xp and 85 on all materials. If you have to throttle back the speed from the book "best cut" speed....then there is something else wrong with the system or the settings. Usually I find that either there is an issue with low inlet air pressure (bordering 85 to 90 psi measured with a gauge right at the inlet) or the real height during steady state cutting is too high. Either of these issues will likely cause the need for slower cut speed for decent cut quality. I have been to many sites in the field that claim they must slow down below the Hypertherm book specs, every time I have the machine running at book specs in minutes. One thing to remember, as there are a lot of different cnc machines and height controls out there....just because you set the cut height at .06" or the arc voltage at the chart spec.....does not mean your machine is maintaining the specification! Check the real height, don't rely on the setup numbers to be perfect! Jim Colt Hypertherm

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Re: Fine cut problem

Postby steelfx » Fri Jun 01, 2018 8:42 am

Jim,
That all makes perfect sense. I set my Arc Voltage to Hypertherm Specs, and my CNC Control Software & Screen show that Arc Voltage setting as well as Actual Arc Voltage, which fluctuates continuously. If I notice that the 'actual arc voltage' is much higher or lower than my 'set voltage', I can make adjustments on the fly.
When cutting a lot of tight, small radii on art pieces, for example, I have my machine set to slow down by 80%, just to keep the gantry from 'hammering' itself to death or premature wear/failure.
I agree with what you say in it's entirety...but I don't have someone with your level of expertise to help me squeeze out more IPM, and do it in such a manner that the gantry doesn't take a beating.
It's all moot for me at this point, as it's taken over a year to work out the bugs with my machine. Then Murphy's Law kicked in and my PM85 crash-burned with an 0-30 fault.
Mike from Hypertherm asked for a diagnostic window photo, which I emailed him this a.m., so hopefully we can get it going. As of right now, it's a very large paper-weight.
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Re: Fine cut problem

Postby steelfx » Fri Jun 01, 2018 8:46 am

20180601_043556.jpg

Bill

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Re: Fine cut problem

Postby motoguy » Fri Jun 01, 2018 9:18 am

Bill, if you do a google search for Jim Colt and 0-30, you'll find a lot of info on what (often) causes the 0-30 error. That being said, I picked up my PM85 from the shop yesterday, where the airflow control parts (solenoid, valves) were replaced under warranty due to continuing issues with 0-30 code. I hope to install it today and find that it's fixed. Fingers crossed.
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Re: Fine cut problem

Postby steelfx » Fri Jun 01, 2018 9:22 am

Okay, thank you!
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Re: Fine cut problem

Postby rdj357 » Fri Jun 01, 2018 9:54 am

Bill,

I have my height control set to disable when speed drops below a certain percentage (I vary this setting based on the material and consumables) and that does the trick for me.
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Re: Fine cut problem

Postby steelfx » Fri Jun 01, 2018 10:10 am

Robert,
I know a lot of cutters that do that. I still want height control, especially on thin sheet, so I've never done it. I just slow the IPM speed down on any curve of .5" radius or less, so the gantry isn't slamming around. Just a habit I picked up back in the day when I didn't have two X-Axis Motors, just a slave drive. The machine I have now is much, much tougher than my 1st table, so I probably shouldn't baby it so much.
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Re: Fine cut problem

Postby motoguy » Fri Jun 01, 2018 3:12 pm

With the Finecut, I found I had to reduce speed by 10% and increase voltage, or I'd have "cut through" issues like you're having. For 14ga steel, I believe book specs are 225ipm, 83v, 45a. I had to reduce to 200ipm, 89v, 45a to make sure I didn't have the cut-through issue.

Lots of people will suggest the Finecuts need a "break in" period before they perform at book spec. Jim Colt suggests cutting at .075-.08 with them, vs the book setting of .06. That's essentially increasing the arc voltage above the book spec to get to that height.

Unfortunately, both 1) increasing the cut height, and 2) slowing the cut speed will increase the kerf size. By slowing speed 10%, and / or increasing cut height to .08", the kerf width increases such that there's no benefit over standard 45A consumables (for me). My first 2 years of cutting were 90%+ Finecut. I'm cutting almost exclusively with 45A regular consumable, anymore. If I can't trust the Finecuts to give the benefit of fine cut (thin kerf) without having penetration issues, then there's no benefit to using Finecut.
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Re: Fine cut problem

Postby islander261 » Fri Jun 01, 2018 11:19 pm

Guys

Here is my take on this. I use Finecut consumables in my franken torch with a Thermal Dynamics A-60 power supply. I use the published Duramax torch settings and Jim C's public comments as a starting point for my own cutting parameters. Then I always do straight line cutting tests at desired speed and height to find the correct arc voltage for my system. This is very important because none of this equipment is precision calibrated to laboratory standards so every machine must be checked for arc voltage at desired cutting speed and height. For me this also includes arc current because who knows what the calibration on the amps knob really is (not me). I use a pencil mark on the dial so I can repeat settings that are not on the panel legend. Most of you guys with Hypertherms don't need to do this.

So now to cut to the chase, for my system (and YMWV) on 14ga HR steel these are what I run: 45A ( at least this is what I think it is), 220ipm, initial cut height .070", my arc voltage for this is 74V, yours will be different. I get a kerf width of about .050" or less with a good bit of bevel on the cut. I am cutting yard art pieces so the bevel is not a concern to me.

There has been a lot of discussion about "breaking in" Finecut consumables. I wish Jim C. was able in his official capacity to weigh in on this but I think we all know corporate reality these days. My take on this is: when my THC or sheet surface probing is in error leading to a cut height that is below the publish height of .060" the cut often has problems. In my experience cut height below .060" is the single biggest cause of cutting problems with Finecuts, please take note that I am not claiming to have never had problems with Fincuts not cutting through. So how does this all come together for the "breaking in" of Finecut consumables? The nozzle of the Finecuts has a smallish orifice with sharpish edges. What this causes in a new nozzle is a narrow arc which equals an arc with higher voltage drop across it or to put it another way a higher arc voltage for a fixed cutting height. Most of our THCs will try and compensate for this by lowering the torch to get to the arc voltage set point we have entered. After a little use the nozzle wears a little bit, actually from my observation the sharp edges round a bit letting the arc get a little fatter or decreasing the voltage drop across the arc or to put it another way the arc voltage lowers. This causes the THC to keep the torch height at the preset or raise it slightly keeping the arc length in the "sweet spot" for best performance. I have no scientific measurements to back all of this up, just my observations from using about 20 sets of Finecut consumables a year. I would love to see the cutting data from the HT labs about this subject, I know they have it. I do most of my work with 14ga HR steel and will continue to use the Finecut consumables for the foresee-able future.

BTW I typically get 2,000 plus pierces from a Finecut nozzle and 2 to 3 times that for the copper plus electrode.

John

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Re: Fine cut problem

Postby motoguy » Sun Jun 03, 2018 12:28 am

Interesting. Something to test out. I'd like to be able to use Finecut with the benefits they are supposed to create.
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Re: Fine cut problem

Postby rdj357 » Sun Jun 03, 2018 9:14 am

It all boils down to height control. FineCut consumables are spectacular IF you are able to accurately and consistently maintain the cut height. If you have no THC or a limited/mediocre performing THC then you will hate them.
Robert Johnson
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Re: Fine cut problem

Postby jimcolt » Mon Jun 04, 2018 10:56 am

John,

In my official capacity with Hypertherm (remember we are a 100% employee owned company, and I happen to be the longest term employee.....the resident gray beard) I can say whatever I want! I find that 80% of the time the exact book specs work perfectly on my cnc table with Finecut consumables. On the other 20% of the time and especially on the thicker materials that Finecut consumables are rated for (14, 12 and 10 gauge), I have to increase the arc voltage / cut height from the book spec of .060" to about .075" or .080"....this is to eliminate the non-penetration that I see in certain parts of the cut. The first inclination that most get is that the specs are wrong and they should reduce the cut speed (wrong decision!), which causes a wider kerf and more dross. Stay at the cut speed (is what I do) or even slightly faster and increase the cut height / voltage so the torch maintains that height during steady state cutting. If you choose....you can run at this height for 100 starts or so then reduce the height back to the book setting of .060" (this is because the electrode has developed a pit that increases voltage at a set height because the arc is longer). Call it a break in period if you choose, our process engineers and I have pretty much decided that this occasional need to cut at a higher voltage/ height is caused by higher levels of silicon, manganese and/ or carbon in the steel, and it is one of those things that makes us use our experience with turning the adjustment knobs to tweak for best quality! Honestly...the Fine cut consumables are very sensitive to any changes in height, speed, amperage, air flow, voltage and chemistry of the material being cut as compared to the standard shielded consumables. The other thing I run into every day is that everyone's height control has voltage/height ratios that are different....due to calibration and design of 30 or so different style height control systems.....these systems are not all exactly the same....so one set of "book specs" will not be perfect for every machine. Anyway....raise the height when using Finecut on 14, 12 and 10 gauge by increasing voltage by 3 to 5 volts or cut height (Plasmacam as an example uses voltage sampling...so you set the height you want as physical height and it auto sets voltage to maintain that height) by .015 to .020", stay at the book speed (I sometimes go a few ipm faster for less dross)....and you will solve issues with non penetration. Jim Colt Hypertherm



islander261 wrote:Guys

Here is my take on this. I use Finecut consumables in my franken torch with a Thermal Dynamics A-60 power supply. I use the published Duramax torch settings and Jim C's public comments as a starting point for my own cutting parameters. Then I always do straight line cutting tests at desired speed and height to find the correct arc voltage for my system. This is very important because none of this equipment is precision calibrated to laboratory standards so every machine must be checked for arc voltage at desired cutting speed and height. For me this also includes arc current because who knows what the calibration on the amps knob really is (not me). I use a pencil mark on the dial so I can repeat settings that are not on the panel legend. Most of you guys with Hypertherms don't need to do this.

So now to cut to the chase, for my system (and YMWV) on 14ga HR steel these are what I run: 45A ( at least this is what I think it is), 220ipm, initial cut height .070", my arc voltage for this is 74V, yours will be different. I get a kerf width of about .050" or less with a good bit of bevel on the cut. I am cutting yard art pieces so the bevel is not a concern to me.

There has been a lot of discussion about "breaking in" Finecut consumables. I wish Jim C. was able in his official capacity to weigh in on this but I think we all know corporate reality these days. My take on this is: when my THC or sheet surface probing is in error leading to a cut height that is below the publish height of .060" the cut often has problems. In my experience cut height below .060" is the single biggest cause of cutting problems with Finecuts, please take note that I am not claiming to have never had problems with Fincuts not cutting through. So how does this all come together for the "breaking in" of Finecut consumables? The nozzle of the Finecuts has a smallish orifice with sharpish edges. What this causes in a new nozzle is a narrow arc which equals an arc with higher voltage drop across it or to put it another way a higher arc voltage for a fixed cutting height. Most of our THCs will try and compensate for this by lowering the torch to get to the arc voltage set point we have entered. After a little use the nozzle wears a little bit, actually from my observation the sharp edges round a bit letting the arc get a little fatter or decreasing the voltage drop across the arc or to put it another way the arc voltage lowers. This causes the THC to keep the torch height at the preset or raise it slightly keeping the arc length in the "sweet spot" for best performance. I have no scientific measurements to back all of this up, just my observations from using about 20 sets of Finecut consumables a year. I would love to see the cutting data from the HT labs about this subject, I know they have it. I do most of my work with 14ga HR steel and will continue to use the Finecut consumables for the foresee-able future.

BTW I typically get 2,000 plus pierces from a Finecut nozzle and 2 to 3 times that for the copper plus electrode.

John

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Re: Fine cut problem

Postby islander261 » Mon Jun 04, 2018 11:45 am

Jim

Thank you an official response to this subject.

I find that on my system when using the copper plus electrode at 100 pierces I can't even see any insert wear!

John


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