plasmac cutting holes

I am wondering if there is scope for a better mouse trap at cutting holes?

I am converting a macro I have created for holes,. but was wondering if it was possible to add a parameter to the plasmac material file for hole factor (hf) which would be a number from 0-1 and accounts for trailing and leading kerf crossing. (is there a way to add fields and retrieve custom fields from the material file??)

it is very similar to hypertherm true hole, using an arc for a leadin

You probably could modify the python data structure quite easilly to add a couple more fields. Personally I think its the wrong way to go. Some enhancements to state tags could build hole processing to new heights that is superior to the gcode based methods Hypertherm use. Let LCNC fully automate it in real time....

I think also you need to be confident of the Plasmac kerf crossing algorithm. Not many people have played with it. It would be very useful for hole cutting to catch a dive on a falling slug. But not many people cut thick material where this is really required.

just doing it by math, no interest in anything else thanks

robertspark wrote:

just doing it by math, no interest in anything else thanks

Yeh I know. Everybody is quite comfy with plsmac now and nobody is really trying to break new ground.

But if you go the safe way, looks like you would start here (well in this file somewhere) But Phill would be able to add guidance.
github.com/LinuxCNC/linuxcnc/blob/master...c/plasmac_run.py#L99

Also look at how he does conditional handling in the materials file for the rs485 code. I think its turned on in the config or ini file somewhere

thanks very much.

thats the problem when you have a mouse trap that works.... whats the point in a better mouse trap..... I'm sure at some point everyone was fairly content with model T fords .... till the model A came along and sold 4.8million ~ 3 years..... (the model T sold ~15 million in 18 years).

A bit like cnc... first you are just happy to cut something / anything... then you wonder if there is a better finish to be gained , etc etc

But now some cars are self driving or have collision avoidance because people built better mousetraps...

phillc54 wrote:

robertspark wrote:

Sorry, there is no way to add/read custom parameters without hacking the code.

No problem Phil, I understand, there is no way to satisfy everyones needs, I may just pass the parameters via m-code 100-199 P or Q parameters (exc. M190 obviously).

I have an algorithm to stop the torch as the leading kerf crosses the trailing kerf, and with PlasmaC that is obviously possible via M62 P3.

I also like an arc for a leadin given it allows for a smoother transition (IMO, YMMV, each to their own), between the leadin and the cut and the lead out and allows for smoother acceleration / less jolt and jerk, especially on thinner materials (2mm / 14g / 0.080")

www.hypertherm.com/learn/about-our-produ...y2/plasma/true-hole/

Th following are some small holes for me to try on 2mm mild steel (~16g) at 2.5t which is sort of the limit of air plasma

File Attachment:

File Name: BoltholeSi...mmOD.txt
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File Attachment:

File Name: BoltholeSi...stop.txt
File Size:1 KB

File Attachment:

File Name: BoltholeSi...top2.txt
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I'm just curious, per the hypertherm video are you adjusting the current on the fly or using O2?

I wont be using O2, I will be adjusting the amperage at some point though (just probably not for a little while).

those posts were created in sheetcam using a couple of dxf's, although I have an equation to do it too.

It seems that there is a bug in the sheetcam post processor that Les posted in this thread in that it lists the feedrate (fr) as 100 and not 4800.
forum.linuxcnc.org/plasmac/42374-sheetca...code?start=40#207300