HyperTherm Cut Speeds

[Kane17752]

I always cut close to book values and have minimal dross except for detailed areas. My system is not that smart to automatically slow down for those cuts and change amperage.

The only solution would be to lower the amperage and the speed for the whole project (which is not a problem for me). Is there a rule of thumb or a formula that can be used to calculate where I should be, such as 35 amps @ 100ipm?

I can do a bunch of test cuts, but wanted to find a starting point. Using finecuts.

[acourtjester]

I think there is a small misunderstanding about the reason for slowing down for details. It is to maintain sharp cornering not for dross problems. If you slow down for the other parts of the cut you will increase the locations of the dross. Just keep using the charts for the cut speed for different thickness of metal and clean where you have dross. One of the things Jim Colt says is if you are using a 45 amp nozzle cut at the amps, I use 45 amps for the fine cut nozzles I use.

[adbuch]

I cut at the settings recommended by Hypertherm. Not all FineCut uses 45 amps. 16-18 ga. uses 40 amps, and 20 ga. and thinner uses 30 amps.
David

Low Speed FineCut Mild Steel.jpg (75.94 KiB) Viewed 21608 times

Low Speed FineCut Mild Steel.jpg (75.94 KiB) Viewed 21608 times

[weldguy]

I always cut close to book values and have minimal dross except for detailed areas. My system is not that smart to automatically slow down for those cuts and change amperage.

The only solution would be to lower the amperage and the speed for the whole project (which is not a problem for me). Is there a rule of thumb or a formula that can be used to calculate where I should be, such as 35 amps @ 100ipm?

I can do a bunch of test cuts, but wanted to find a starting point. Using finecuts.

I think that what your seeing is perfectly normal, minimal dross except for in detailed areas where the torch is moving at a slower cut speed. If you trn down amperage and slow down I believe you will see the same results but it will simply take longer to complete the cut. I'd stick with what your doing and look into a muratic acid/water bath to remove remaining dross and prep your parts for finishing.

[Kane17752]

I never Have seen that chart before. I guess I should of flipped a couple of more pages. Will try those settings. I only use CR. I am not going back to acid.

[djreiswig]

My book stays open to that section. And I flip back to the kerf width chart frequently. I have a lot of the tools programmed in SheetCam already, but I still like to check the chart.

[Haye]

So my table has finally arrived and I started to experiment with some different material thicknesses ect. While starting to use the finecut consumables and using the THC, I get poor results. In the sense of not cutting completely through the material (especially in corners). Using regular consumables and switching THC off everything is fine. I just saw this threat with a 'low speed FineCut' chart. My manual has the chart below (problems occurred with 2mm material, cutspeed of 5250mm/min). However quality improved slowing down to 4500mm/min. Is this an old manual I have? typo? anything else wrong? I have a HT 65A plasma, fangling controller and THC f1628D.

[acourtjester]

Some have problem with the "Fine Cut consumables" you can do a search here for info. Are you supplying enough pressure to the Plasma cutter, it is recommended to attach a pressure gauge at the rear of the Hypertherm to monitor the pressure while cutting.

[Old Iron]

I'm one of those that have trouble using Fine Cut so, I just stick to the standard consumables, have very good results and very little to no easy to remove dross at book specs.
I'm even running a cheap ole Proma that does an acceptable job.

[Haye]

A I see my last post was not clear enough. David posted a "low speed finecut chart", however I could not remember this chart from my own manual (quite sure because I had problems with the 2mm 5252mm/sec). So I looked for a manual that did inude this low speed chart. However when I found this manual, also the 'regular' finecut table was different than the screenshot I posted! It showed speeds of 4800mm/min instead of 5250! right in the ballpark where my tests showed best cut quality. So for others that might have problems with finecut consumables, make sure you have the correct manual

[Rodw]

A I see my last post was not clear enough. David posted a "low speed finecut chart", however I could not remember this chart from my own manual (quite sure because I had problems with the 2mm 5252mm/sec). So I looked for a manual that did inude this low speed chart. However when I found this manual, also the 'regular' finecut table was different than the screenshot I posted! It showed speeds of 4800mm/min instead of 5250! right in the ballpark where my tests showed best cut quality. So for others that might have problems with finecut consumables, make sure you have the correct manual

Its actually quite mad how crazy fast hypertherm cut charts are. My Thermal Dynamics A120 quotes cuts for 2mm mild steel as being 2219 mm/min @ 40 amps. I'm quite sure everything must be perfect @5252 mm/min.

[ScottRa]

I’ve looked at the chart David posted before and wondered about the footnote posted about 14 and 16 ga not being dross free. Voltage and speed change some around those settings. The amperage makes a 5 amp step there but makes a 10 amp step between some of the lighter gauges with no comments about dross. Anyone know or wanna speculate why those two gauges act that way?

Scott

[Creative25]

I just started to use fine cut nozzles.
Seems they are great for thin methal.
I cut 1.6mm at 6000 mm/min.
Virtually no dross. But it makes some waves.
I wonder it is due to vibrations or if the arc is wondering around.
But with shapes I had to drop to 5000mm.

But this is still insanely fast.
There is someone who asks if I can cut 0.8 mm stainless.
They want letters about 30mm high. Is it realistic to have good results with such small sizes? Even 3800mm is quite fast for such small details. What speeds do you use for such small detailed things?

[adbuch]

I just started to use fine cut nozzles.
Seems they are great for thin methal.
I cut 1.6mm at 6000 mm/min.
Virtually no dross. But it makes some waves.
I wonder it is due to vibrations or if the arc is wondering around.
But with shapes I had to drop to 5000mm.

But this is still insanely fast.
There is someone who asks if I can cut 0.8 mm stainless.
They want letters about 30mm high. Is it realistic to have good results with such small sizes? Even 3800mm is quite fast for such small details. What speeds do you use for such small detailed things?

When you say "Fine Cut" nozzles - I assume there are the same brand as your plasma cutter. Please refresh my memory - what plasma cutter do you have? There are cut charts for stainless steel using the Hypertherm FineCut consumables, but they may or may not work for your particular setup.

David

fine cut ss.jpg (51.75 KiB) Viewed 19349 times

fine cut ss.jpg (51.75 KiB) Viewed 19349 times

[Creative25]

I have a hyperterm powermax 45
These speeds are just too fast small shapes look bad.
I am interested how much other forum members slow down to get good results with small details like letters less than 30mm high or small peace’s of art.

[adbuch]

One thing that can really help is to reduce your corner acceleration setting. For parts with lots of small details, I reduce my corner acceleration from the standard setting of 0.2g to a smaller value in the range of 0.02 to 0.05g. I was not aware that FineCut consumables are available for the powermax 45. Some use the consumables from the powermax 30 installed onto the Powermax 45 with good results.

"The Powermax45 can use the Powermax30 consumables (the retaining cap, nozzle, electrode, swirl ring).....this allows for unshielded cutting at up to 30 amps....with a slightly narrower kerf width. Expect shorter consumable life than you will get with the 45 amp shielded parts...part of the shield technology advantage is consumable life."


David

[Creative25]

Where do you reduce corner acceleration in your cam program or in the machine settings?

Where fine cut really shines for me is ohmic sensing.
This you can only do with a shield that is insulated from the nozzle. It is much faster and saves me some air.

I did some interesting maths

Standard nozzle 35a x125 volts = 4375 W

Fine it 35 A X 75 volts = 2625 W

So this will help with my power problem.

[adbuch]

For my Plasmacam table, everything is integrated into a single package. So the same program does the drawing, cut paths, g-code, settings, etc.

For my Hypertherm 45xp and 85 plasma cutter, I can use the same ohmic cap (for ohmic sensing) for FineCuts as well as regular consumables.

The benefits of the FineCuts are narrow kerf width, less heat into the part (less warping), and much better definition for detailed cuts. I generally use the FineCuts for 10 ga. and thinner material. (10 ga. is approximately 3mm in thickness).

That is great benefit to you that it will help with your power consumption.

David

[adbuch]

Since I think you use SheetCam, I'm not sure if there is a way to set the corner acceleration. I know there are path rules for cutting slower on smaller circles. I'm not sure if that applies only to circles or to any curves under a specified radius.

Design Edge has independent settings for corner acceleration and slower on circles/curves under specified diameter.

David

[adbuch]

[weldguy]

Indeed the speeds get fast on thinner material and some machines just don't work well at those speeds. If that were the case for me I turn the amperage down which will allow you to get your speeds down to a rate your machine can handle. Do some straight line test cuts at lower amps and find out what speeds are producing good cuts at lower amperage's.

[Creative25]

I found a way to get better corners I reduced the acceleration of the x and y axis. But at the very slow speeds on corners I get nasty dross that is difficult to remove.
So to me it seems making the gantry more rigid is the way to go. So I can have faster cutting in tight corners and with it less dross.

[weldguy]

I found a way to get better corners I reduced the acceleration of the x and y axis. But at the very slow speeds on corners I get nasty dross that is difficult to remove.
So to me it seems making the gantry more rigid is the way to go. So I can have faster cutting in tight corners and with it less dross.

A more rigid and/or lighter gantry will certainly help. Have you tried just turning the amps down, slowing the speeds down, and using standard acceleration that doesn't slow the torch down or at least very little in the corners?

[Creative25]

I have 2 configurations on my machine 750 mm2/s as standard this works great for radiuses down to 10mm.

Then I have a slower one 300mm2/s for letters that are 25 mm high. For sure I can increase until there is a quality loss.

I found on 1.6 mm steel plate going down to 25 a helps to get less dross around corners. But straight lines have more.

I think it is always about finding the best trade off for each situation.

For bigger letters I stick to the faster configuration.

[adbuch]

I have 2 configurations on my machine 750 mm2/s as standard this works great for radiuses down to 10mm.

Then I have a slower one 300mm2/s for letters that are 25 mm high. For sure I can increase until there is a quality loss.

I found on 1.6 mm steel plate going down to 25 a helps to get less dross around corners. But straight lines have more.

I think it is always about finding the best trade off for each situation.

For bigger letters I stick to the faster configuration.

This is great to know! After some trial and error you have found the settings that work best for your particular machine.
Dvid