Revisiting those blasted divots...

[davek0974]

I din't realise you could load a tap file back into sheetcam, it doesn't look pretty on mine, but neither does my own files, maybe I'm using the wrong import settings.

looks bad here too:)

[Old Iron]

If you use gcode filters then you can. It's a little confusing right here but, you choose "Yes" and it loads them correctly.

[Old Iron]

I scrolled in close up using Sheetcam to show the problem and then done a screen shot.
The first app is just MS Paint that is on my computer. I used it to save the screen shot as a jpeg image so I could post that on this thread.

[Old Iron]

Try this Sheetcam file and see if it works for you.
If I'm way off then I'll sit back and learn something

[davek0974]

cant see any difference?
could not use the tool as i have no tool 0 and cut direction was backwards?

[Old Iron]

Sorry about that.

[Old Iron]

I'm trying to learn a little here so, I gave it one more shot.
Changed the layer0 to layer1
Changed the cut direction.
The first file is as follow:
The lead-ins (perpendicular) and lead-outs (arc) are on the same side of the kerf lines.
The second file is as follow:
The lead-ins (arc) and lead-outs (arc) are on the same side of the kerf lines.
Hope this helps.

[davek0974]

Back again

Took a mix of settings from the thread and from PM's (thanks BTW) and tried running at 30A on the 45A consumables.
3mm alu
30A
3.8mm pierce height
1.5mm cut height
2540mm/min speed
0 pierce delay (machine minimum is 0.3s)
4mm perp Lead-in
2mm arc lead-out
No over-burn

Looks fine on top...

Not too shabby on the back, mostly dust and heavy dross where the bed slat was...

Divots look fairly acceptable I think ?

Feeling on a positive edge , I grabbed the lump of aluminium I was using in the earlier tests and was getting shite results with - exactly the same settings as the last cut above, side-by-side comparison of the back side

Clearly the lump of junk pretending to be alu was indeed chewing gum! It was some time back now but i had a delivery of it sent by mistake by my useless alloy supplier, I got the job done and thought I'd dumped all the drops but it seems i missed one

So, lesson learnt, when trying to improve cut quality and it's not working, change the material!

However, I do think there is a good reason to stick with the lower power - the machine runs slower and more accurately, run time on the PM45 is 100%

Might be some small gains to be had playing with the settings but what do you guys reckon????

[vmax549]

Much better, good job. Write those settings in your book. Then you can fine tune from there IF needed. Not much need for a leadout IF your leadin is doing its job. It will just be cutting air.

(;-) TP

[davek0974]

Yes, noted.

Also noted is to change the metal before messing with settings, just in case.

I will try a cut with no lead-out and same settings, see what we get.

Thanks

[davek0974]

No lead out gives a worse divot

Seems best setting on 3mm aluminium is
2500mm/min
30A on 45A consumables
Perp lead in
arc lead out

[SeanP]

Looking good now Dave, I'll make a note of those settings for 3mm, good with the 30a setting as well,thanks for sharing.
I quite often use 30a with 45a consumables on 2mm steel that cuts well when you want to slow down, not tried any thicker though.
Only tried the 30a consumables on 2mm stainless so far, I seem to get a lot worse dross though, they are nice for slowing down as well.

[davek0974]

Yeah, i tried dialling back on the 3mm steel but the benefits were minimal, more dross but lower speed.

I'll stick to full-on with the steel I think.

The hardest part I find is making notes of all the blasted settings, so many options, so easy to just keep messing and lose a good combination.

I was surprised how bad that aluminium was though, from what records I have, I think they sent me 1050 grade which is 99% pure aluminium - nasty gummy muck, I usually use 5251 which cuts much better.

[Old Iron]

Good to see ya got it figured out!!!!!!!!!!

[davek0974]

Got this piece figured, that just leaves the other 6,8765,234 pieces of the jigsaw to figure out

[davek0974]

I can't figure this out.

Cutting a simple job today, one pierce only. I reset my parameters to how I had it before, 3mm steel 45A with 4mm perp lead-in, 2mm arc lead-out, 5mm over-burn, torch off 3mm before end.

Now, with a 5mm over-burn and the torch off 2mm AFTER the end of normal cut - 3mm before end, how is it possible that i still had a nasty little tab that was maybe 90% cut through, just before the point where the lead-in ended and started its full cut???

I read the G-code line by line and it's not killing the torch before it should, it's not doing anything odd before the M10P1 kills the torch in the over-burn.

Very odd, this is the same issue i had with the Alu before, not as bad but the same fault.

Again, reading the 'net suggests slowing down before the end to maybe 50% to allow the tail of the flame to catch up, but this is only 3mm thick sheet? Might be worth a try.

I am also going to go back and try a basic perp in and arc out which is all i used to have, left a divot but always dropped the part out.

[SeanP]

I get that with stainless as well sometimes, you should be able to cure it with a little slowdown rule a couple of mm or so before the end.
I feel the flame skips to the other side of the leadin leaving that tag.

[davek0974]

That does seem to be what happens but I cant see what is making the flame jump suddenly, there is the lead-in gap approaching but why should a gap cause it to jump ahead, if that is what is happening????

On the Alu it was jumping maybe 3mm of cut, although I think the lag was much higher so that does kind of play-ball with the jump - maybe its all speed related and I'm just cutting right at the top speed limit, there's a thought?????

[muzza]

That does seem to be what happens but I cant see what is making the flame jump suddenly, there is the lead-in gap approaching but why should a gap cause it to jump ahead, if that is what is happening????

Maybe the flame is chasing material to complete the arc and when it is part way through on 3mm and the kerf width is only 1.2 mm the material on the other side is much closer hence the shift leaving that little tab at the bottom of the cut.
Murray

[vmax549]

Dave just as a test try moving the Start points 90 degrees from where they are in your code.

(;-) TP

[davek0974]

Will do

[davek0974]

Ok, from front to back...

3mm steel, 45A, ALL parts dropped fully out.

1 - basic setup - 4mm perpendicular in, 2mm arc out, no rules, no over-burn
2 - 4mm perpendicular in, 2mm arc out, 0.5mm over-burn, 0mm before end (not inc lead in) torch off
3 - 4mm perpendicular in, 2mm tangent out, 0.5mm over-burn, 0mm before end (not inc lead in) torch off, 2mm before set 50% speed
4 - as 3 but arc out
5 - as 3 but start rotated 90deg to right

Top edges...

Aperture edges...

Rotated start...

seems to me I need the hole setting from 2 and the edge setting from 1 ??