CNC Plasma help...

[gerrymoore]

In my humble opinion your going much too fast. I use 800mm/minute on all my cuts 1.5mm, 2mm and 3mm and just adjust the current between 18 and 22 amps and get near perfect cuts every time. It might take a little bit longer but it works.

 

[Davek0974]

I'm fine with going slow but...

1 - Everyone else is telling me to speed up
2 - If it worked a week ago at 2400, why does it not now work at 2000?

I will try low and slow.

 

[Davek0974]

If in doubt, turn the power up!

running at 30A, cuts are much better now

 

[Jim Davey]

No, the torch cable is suspended over the top and there is plenty of free movement, the bevelling only happened on the 32A cut but only on the horizontal edges, including the round hole but not quite as bad.

The 35a one seems best but where others are using 20a I'm having to run 35-40a which seems odd to me. I spoke to r-tech about the oversize torch and was told they always ship bigger with CNC because they get hotter! I call BS on that one as the power is the same so surely the torch will not get any hotter than a hand held? Personally I think it would be happier with a 20-50a torch and 0.8-1mm tips.

Machine torches as a rule tend to be 'on' for more of the time. A man with a plasma tends to stop often to reposition, pick his nose, drink tea, measure, mark out, cut a bit more etc etc. A mechanised plasma could be running for hours at a time with little or no rest, this is of course going to allow more heat to build up. Instead to trying to swap for a smaller torch, I'd be enquiring after smaller tips for the machine torch as 1.1s are pretty large for such thin material.

 

[Davek0974]

Have done some fine tuning, reset the speed and acceleration settings and then tried the file for the picture attached, this is the most detailed I have tried yet and was met with total success, the shape matches the file, it has some surprisingly fine detail in it and apart from the metal being some galvanised crap from the scrap heap, is just about perfect.

There is some dross but a tap and it and falls off so I'm not worried about trying to get rid of that, looking at the way the machine was whipping around it, I really don't think more speed is possible so dross is a thing that I live with I guess?

This is 1mm galv sheet @ 3300mm/min and 25A on standard consumables.

 

[Davek0974]

Much better - 5mm steel, 30A'900mm/min

Very sharp

 

[Normsthename]

Looks like you have got it dialled in nicely!

Andy

 

[Davek0974]

I think so, at least for this thickness

I have also discovered why the hole at the top suffered - I had sheetcam set wrong and it reduced the speed way too far.