Cutting quality Jasic Cut80 plasma cutter

[Reb0rn]

Hello,

At the moment i cut hot rolled steel, 3mm with only 37,5A while using a 45 cutting tip and 1000 mm/min (about 40 inch/min), it has on the whole cutting line dross on the downside.

I have some trouble with the settings. the manual of the torch says i should use about 4000 mm/min, 45A, but when i did that, it went to fast and didnt go through the material. When staying in that high speed range, where it did go through, i noticed the lines arent clean. there were quite some mistakes/burn-ins in the lines. i lowered the speed to a point where i got the clean as possible line, but it has lots of slag. The cut side had a small arc in it, so not a S-line.

Si i basically feel that i am cutting to slow, but i had quite some problems on higher speeds..

I am using a Jasic Cut80 plasma cutter with a TM125 machine torch (uses Hypertherm consumables)
https://www.jasic.co.uk/_files/ugd/bac0 ... 1724a5.pdf

This in combination with a Pritec (small Dutch company) table.
https://www.pritec-automation.com/en/product/acros-150/

Any advice for me?

Kind regards,
Valère

[adbuch]

I would also check your cut height. You can pause your cutter in the middle of a cut and physically measure your actual torch to material distance.
David

[Reb0rn]

When i started cutting i had it at 1,5mm as recommended. But the head touched the material all the time and dragged it. I raised the hight bit by bit and now i am at about 2.5mm. I will try it again lower, and check it.

[adbuch]

Sounds like your thc is not working correctly. If proper arc voltage monitoring it should keep the cut height right at your 0.060" setting. If you are not using thc, then you may have a problem with your z motor.
David

[Reb0rn]

Im not using it yet. I tried to determine the voltage at 2mm heught, but it was over 230v, and my table could only handle below 230v because it runs on 230V.

The chart says 128V i might try that.

But THC overrules the cut height setting?

[weldguy]

Forget about the THC, that will only cause more headaches until you get things working well without THC.

Keep your cut height at 1.5mm, if it is dragging find out why. Is your material warping up and hitting it? If so fix that and maintain 1.5mm height for your tests.

Draw a simple straight line 24" long and cut a series of these. Increase your cut speed with each line you cut until you find the speed you are traveling too fast and use the previously successful cut speed.

How does the cut look after maintaining proper height and finding fastest usable speed?

[Reb0rn]

Thats why i didnt bother the THC, i see it as something extra, first need to get the basics correct.

I will try that with all the specs from the chart and see where it gets me.

Would you suggest to use the maximun Ampere every time? So always for the 45A tip 42,5A (5% below max)

Before i had a bit higher speed at my current settings, but it didnt go all the way through in the corners. So isn't it better to make a curvy testcut?

[acourtjester]

You should use 45 amps for a 45 amp nozzle, adjust your speed as weldguy says. You want to have very small amount of bottom dross by cutting at the right speed and have full penetration. Now as to curvy or corner cuts it should not be different, you will be cutting both with doing normal cuts. Thinking about it cutting a box or a circle the torch will change directions 4 times while cutting both. It just does not look that way while cutting a circle but it does happen. This happens because of the X and Y motors change directions to complete either cuts.

[adbuch]

I agree with both Weldguy and Tom here. Since you are not using thc, then you should be able to set your cut height and assuming your material is flat and not warped - maintain your cut height as you cut your part. You could do a simple straight line cut and pause your machine and physically measure your torch to material distance and adjust accordingly. Weldguy's suggestion about doing multiple cuts to dial in your cut speed is a good one. Your 45 amp nozzle is rated for 45 amps and less. On some thinner materials (22 ga. steel for example) you may wish to dial back your current setting to 30 amps or so. It depends on your particular plasma cutter.
David

[Reb0rn]

I tried some dry-runs.

I just found out my cut height is awfully wrong. With 1.5mm height it scratches over 3mm plate, that isn't warped at all.
Tried 8mm height, came out 6mm. 3,5mm about 1mm. I adjusted the height in Sheetcam for this ofcourse.

So i feel the z-axis isn't zeroing correctly.... Can i adjust this myself?

[adbuch]

I believe you should be able to move your Z down until your torch contacts your material surface, then zero out your Z in your control program. In any case, you need to adjust the number in your program to get to the 1.5mm value you are after. If 3.5mm gives you 1mm, then I would expect that a setting of 4.0mm would give you the actual 1.5mm torch to material distance you are after. Tom will know more about the SheetCam settings than I do.
David

[Reb0rn]

i will look into that. the z axis had a probe in it so each time it measures again the height, and we can move the z axis up by hand and it has some slack in it before the switch clicks

[Reb0rn]

I just did some test cuts with adjusted height so the real height is about 1.5mm. i can run at 2500 mm/min with a little bit dross on de downside. (2800 had some top dross) But the weird thing is, the manual says it should be 4000 mm/min...

But still the piece is smaller at the top than on the bottom...

[adbuch]

Perhaps post some pictures of the part you have cut so we can see exactly what you are getting.
David

[weldguy]

I am not familiar with your plasma cutter but as far as the speed goes I suspect that the plasma manufacturer may be over inflating their claims about cut speed for marketing purposes and since your cut height is not accurate to the set value I suspect your speed is also not what you think it is.

The important thing is that your cut looks good with minimal dross. If it doesn't cut through on the corners it could be that the machine is not tuned in perfect to slow down in these areas and the easy fix for that at the moment is to simply reduce your cutting speed a little bit more. All the fine tuning can be done once you are comfortable with the machine in its basic operating conditions.

Curious how things work out for you. Best of luck.

[acourtjester]

AS you are learning each table/system will need to calibrated/setup to make it do the operations correctly for a great operation. Gearing, motor steps,motor speed, plasma unit output are variables that need to be established. The time spent with these setup will be paid back with good cuts.
If the steps per are off for the Z this will throw the whole pierce and cut height off as it will not match the values you are trying to set (book settings).
In SheetCam each tool (plasma metal thickness, and amps) will need the pierce and cut heights to be set. Yours will be in MM be sure SheetCam is setup of metric.

asheet3.JPG (60.98 KiB) Viewed 1417 times

If you are using a floating head switch here is a video on how to set the backlash of the switch.

[Reb0rn]

Perhaps post some pictures of the part you have cut so we can see exactly what you are getting.
David

This is 3mm steel, 45A tip, 42,5A, 2500mm/min speed and 1,5mm height.

This is still to much of an angle. I've read about the cut angularity on hypertherm. They say it would be one of the following:
Nozzle (good as new)
Height (i just compensated)
Amperage (is at 42,5)
Speed (2500 mm/sec)

So i think i still try to lower the speed, because all others must be good.

AS you are learning each table/system will need to calibrated/setup to make it do the operations correctly for a great operation. Gearing, motor steps,motor speed, plasma unit output are variables that need to be established. The time spent with these setup will be paid back with good cuts.
If the steps per are off for the Z this will throw the whole pierce and cut height off as it will not match the values you are trying to set (book settings).
In SheetCam each tool (plasma metal thickness, and amps) will need the pierce and cut heights to be set. Yours will be in MM be sure SheetCam is setup of metric.

If you are using a floating head switch here is a video on how to set the backlash of the switch.

Thanks for this video! The only thing is i can't find all the settings in my new MACH3, but i saw some other vids that put the difference in height for the floating switch in the postprocessor. I will try to play with that aswell. All my Sheetcam settings are in mm.

I am not familiar with your plasma cutter but as far as the speed goes I suspect that the plasma manufacturer may be over inflating their claims about cut speed for marketing purposes and since your cut height is not accurate to the set value I suspect your speed is also not what you think it is.

The important thing is that your cut looks good with minimal dross. If it doesn't cut through on the corners it could be that the machine is not tuned in perfect to slow down in these areas and the easy fix for that at the moment is to simply reduce your cutting speed a little bit more. All the fine tuning can be done once you are comfortable with the machine in its basic operating conditions.

Curious how things work out for you. Best of luck.

I think i should try to let it run 1000mm and time it to see if the speed is accurate. Not the most important thing, but when 1000mm/min is like 1500mm/min, i know that i will get closer to the charts.

The sad thing about all of this is that you pay quite some money on a plasma cutter and an table, and it has all those "problems'' and wrong charts....


Thanks all for the help!

[adbuch]

Perhaps post some pictures of the part you have cut so we can see exactly what you are getting.
David

https://imgur.com/a/ScN5LYW

This is 3mm steel, 45A tip, 42,5A, 2500mm/min speed and 1,5mm height.

This is still to much of an angle. I've read about the cut angularity on hypertherm. They say it would be one of the following:
Nozzle (good as new)
Height (i just compensated)
Amperage (is at 42,5)
Speed (2500 mm/sec)

From your photo it appears that your torch may not be perpendicular to your work surface. Of it could be an illusion from the photo.
David

[acourtjester]

Ok lets get a few things straight. Each table can have totally different floating head switch backlash, this is due to the switch itself and positioning of the switch placement. If there is a gap between the switch actuator and what trips the switch, this gap is in the switch backlash amount. this image is from an older table I built, but you can see how the switch and actuator are just touching. In the G-code there is a routine to operate the floating switch and then to zero out the Z DRO and then move to the pierce height set in SheetCam. Not all G-codes are setup for a floating head switch, this is similar to using a Ohmic sensor to detect the metal surface. Look at your G-code and see if there is a G28 at the beginning. There should also be some G92 codes too. Here is a G-code with the floating head routine in it (Pierce height is low 0.090" thin metal). G28 home the Z axis look from switch trip.
G92 reset Z DRO to 0.0 before switch backlash move. G0 to move Z amount of the switch backlash, G92 zero the Z DRO before moving to pierce height. G0 move to 0.090" pierce height, M3 fire torch to pierce metal.
Keep plugging you will get there.

[Reb0rn]

Perhaps post some pictures of the part you have cut so we can see exactly what you are getting.
David

https://imgur.com/a/ScN5LYW
T7oqadS.jpeg

This is 3mm steel, 45A tip, 42,5A, 2500mm/min speed and 1,5mm height.

This is still to much of an angle. I've read about the cut angularity on hypertherm. They say it would be one of the following:
Nozzle (good as new)
Height (i just compensated)
Amperage (is at 42,5)
Speed (2500 mm/sec)

From your photo it appears that your torch may not be perpendicular to your work surface. Of it could be an illusion from the photo.
David

The torch is levelled, but it has a thick cable that oftens pulls on it. have to think of something for that... So i think it is a combination of speed and the cable problem.

[adbuch]

Yes - you will most definitely need to beef up your torch mount so the torch does not move from the cable pulling on it. Also any slop in your z axis should be eliminated.
David

[Plasma-art]

I noticed it only has a nema17 on the Z axis, is it geared or direct drive?
Nema17 is pretty tiny and with the weight of the torch it would not surprise me if it is skipping steps, does not take much if its direct drive in my experience.

[adbuch]

I noticed it only has a nema17 on the Z axis, is it geared or direct drive?
Nema17 is pretty tiny and with the weight of the torch it would not surprise me if it is skipping steps, does not take much if its direct drive in my experience.

[weldguy]

I think your pretty close.

Looking at the edge taper in your image I would suspect your torch height is too high but if it actually measures 1.5mm (.060") when cutting then that is likely not the problem especially since the taper seems to be steeper on 1 side than the other.

Since the taper is steeper on 1 side than the other it could be that hole in your cutting nozzle is no longer perfectly round. You may not be able to see this with the naked eye, if your older like me a magnifying glass to inspect the nozzle. Have a look for a damaged nozzle, this is common for new users since they often touch material when cutting, use too long a pierce delay, have dirty wet air, etc.

Folks always say to me "it's a brand new nozzle" but that doesn't matter, 1 pierce with wet air is all it takes to damage a nozzle. You will need to inspect it and definitively determine if it is good or not.

Aside from that maybe this is just how that plasma cutter cuts, I am not sure, never used one.

[Reb0rn]

I adjusted the switch ofsett for the z-axis, perfectly 1,5mm height, also pierce height is correct.

The cuts are way better than yesterday, did a test from 1750-2500 mm/min. The edge bevel is almost gone, and i feel that somewhere around 2300 the side is almost no bevel, a bit bottom dross, and a little bit top dross. 1750 has same top dross, almost none bottom dross. Picture will follow!

We found a solution for the torch movement because of the pulling of the cable. we are going to fasten the cable on a stable point on the mount, so the cable only pulls on that point (that has no slack in it). Between that point and the torch we make a nice loop, so the z-axis still can move.

I believe the z-axis nema is direct drive. i see a small "motorbox" on top of the spindle. but if it works for now it is ok.

But now the next problem... after fixing cut and pierce height, i went to pierce delay. had it at 0.3 and was more than 1 second! even when i lowered it to 0.1 sec, it remained more than 1 second...

i did find this in the post processor:

if (pierceDelay > 0) then
post.Text (" G04 P")
post.Number (pierceDelay,"0.###")
post.Eol()
end

if i am correct, that should be: pierceDelay,"###" because you cant have 2 dots in it.

next question, when you want to make small letters(+-50mm/2inch) in 3mm steel, best to slow down and turn down amperage i guess?


Thankyou everyone to take their time for me! really appreciate it!