Cutting in Auto

[CX_MetalCraft]

Hi Again,

We're having trouble with our cuts in automatic mode...

We have the blue screen cnc system, everything is digital,

Problem: 1.)

we ran a series of test line cuts in manual mode at the recommended voltage (108v) (40amp tip 40 amp set on machine),

and recorded the average voltage (130v)

however, upon going into auto mode and inputting said recorded voltage (130v),

the torch displayed very unexpected behavior - at 133v the torch would dive into the

material (1.6mm Steel) and then arc while touching the steel...

at 134v the torch would climb to it's maximum height and at times dive again....

WE were able to fiddle with a few of the settings under the setup menu and at

tiems the torch would cut a line, but the arc would again display odd behaviours...


we need

The correct starting variables to input into our CNC...

what goes into setup menu?

please assist...

Knysna Metal Craft...

[Mike@Torchmate]

Hi Again,

We're having trouble with our cuts in automatic mode...

We have the blue screen cnc system, everything is digital,

Problem: 1.)

we ran a series of test line cuts in manual mode at the recommended voltage (108v) (40amp tip 40 amp set on machine),

and recorded the average voltage (130v)

however, upon going into auto mode and inputting said recorded voltage (130v),

the torch displayed very unexpected behavior - at 133v the torch would dive into the

material (1.6mm Steel) and then arc while touching the steel...

at 134v the torch would climb to it's maximum height and at times dive again....

WE were able to fiddle with a few of the settings under the setup menu and at

tiems the torch would cut a line, but the arc would again display odd behaviours...


we need

The correct starting variables to input into our CNC...

what goes into setup menu?

please assist...

Knysna Metal Craft...

It sounds more like the problem would be associated with your dwell timing of the AVHC system, and the Pierce Height and Initial Cut Height settings.

For finding the automatic voltage your methods are correct, and 130 volts will more than likely be your correct number for that setting. However at the beginning of the cut you need to set the Pierce Height and Initial Cut Height settings to their appropriate levels. Typically the pierce height would equal approximately 3/16" (4.75mm) off the plate, and the initial cut height would be slightly lower than that, about 1/8" (3.2mm). The machine will sense the material, and back off to pierce height, at which point it will activate the cutting arc. The cutting arc should ignite, and then the height control would move into the initial cut height setting, and move down slightly, before the machine started its X and Y motions.

The timing of when the height control drops to the initial cut height after it reaches its pierce height is controlled in two different ways, depending on how your system is setup. If you are using an OK to Move signal from the plasma cutter, the Pierce Delay setting in the Setup menu determines how long after it receives the signal from the plasma cutter, before it drops to initial cut height. If you are not using the OK to Move signal, the pierce delay controls how long after reaching the pierce height before it drops down to initial cut height, and initiates motion.

I'm pretty sure you have Jack's Email, if you have any further questions, please let him know!

-Mike

[CX_MetalCraft]

Hi Mike,

Thanks for that,

what we're really in need of right now is cut charts

We have the instruction manual which provides some cut charts, but not the ones we need;

we are trying to cut 1.6mm mild steel down to .9mm mild steel at 20amps and 40amps with 20 and 40amp tips respectively...

also Stainless steel from 1.2mm using 20amp and 40amps.

could you please provide us with those?

if not is there anywhere we can get those from?

thanks in advance

[CX_MetalCraft]

also NB,

when we set the pierce height at 0.19inch on the AVHC box, when doing the innitial touch test, the distance between the material and the torch tip was less 4.8mm which is 3/16inch...

We had to chage settings on the AVHC to 0.24inch to bring the tip distance to 4.8mm...

Why would this be happening?

How could we correct this?

And would this effect any of the other settings eg. cut height, considering that the Torch height control displayed value does not correlate with the actual height...?

[LenMcC]

we experienced something similar when we first set up our machine. big difference between the suggested voltage and the observed, the climb and dive into the material thing, all of that. we tried messing with dwell and sense delays and whatnot, and none of it helped. we accidenttaly fixed the issue when we went to neaten up the wires running everywhere. i think we unplugged most of them so we could bundle them nicely, and when we plugged them back in, boom, athc worked AWESOME. we can now plug in the suggested values for current/feed/voltage, and it comes out pretty nice without any adjustments. our best guess is that we originally had wires next to each other that were inducing a voltage in the athc system.


i made a nice chart that has the baseline current/feed/voltage settings. i'll post that soon, as i don't have access to it on this computer.

[Mike@Torchmate]

Recommended cut speed charts for mechanized operation are best gotten from the Torch Manufacture. The Arc Voltage numbers provided on those charts are more then likely incorrect, which is why we recommend running the cut in Manual mode and read the average voltage with the correct initial cut height.

Typically if it's thinner material, the AVHC can exert enough force on the material to move it slightly downward when sensing the material. When the system retracts it backs up from that point, and if the material were slightly pressed down, it would bounce back up with the torch. Some compensation in the settings may be required.

[LenMcC]

here's the chart i made... i forget where the data came from, actually... it gets us close to begin, but like mike said, these are only baselines to get you in the ballpark. use the "observed" method to really dial it in. On the chart, the black circles are the "recommended" settings and the open circles are the "work, but not as desirable as recommended". hope this helps!

BTW, we're running a CutMaster 81 with a 1-Torch.

[LenMcC]

CM said he could view the chart, so here's the actual excel file, which is probably more useful anyway.