QtPlasmaC release.

robertspark wrote: the voltage goes up when the torch slows because the kerf gets wider (more material has been cut / blown away than the optimum kerf width).

Exactly! The resistance increases as the arc is stretched looking for material to burn.

You'd have to review your cut charts to see how important pressure was by comparing between amperage values on the same material. Often, the same pressure is used. I also wonder how responsive a pressure valve would be in real time? I think current control would be much more responsive. I did get excited when somebody on the forum here mentioned a plasma brand that had 0-10 volt control of current. I can't remember the brand.

air pressure and current are static on all air plasma systems...... well static during the cut that is, you get to set them before

you can get the electonic regulators to adjust within 0.1 sec, normally the changes being made are small so the response factor can be lower.

_________________________________________________________

to cut you need power and that is an optimum number (like welding ~40A/mm)
power, not exactly / just current or voltage..... if you lower the cut speed, the voltage rises.... but if you lower the current in sync with lowering the feedrate the voltage "should" stay roughly the same because P=V*I.... negating the requirement for locking the torch height..... given the amperage is the bit you are changing and are holding the voltage static......

thats the theory.....

whether it makes the cut any better, that cutting without it..... or whether it causes increased consumable wear than cutting without it..... those are different factors.....

afterall if there is little to no benefit in the end product.... whats the point of go faster stripes...

Deleted as it was off topic.
Sorry Phill.

This topic is about the QtPlasmaC release, can we please keep it to that...

I forgot to mention a big thank you to Chris (cmorley) for his wonderful QtVCP infrastructure that made this possible and also for the changes he made to fit in with the odd way we do things.

robertspark wrote: .... but if you lower the current in sync with lowering the feedrate the voltage "should" stay roughly the same because P=V*I.... negating the requirement for locking the torch height..... given the amperage is the bit you are changing and are holding the voltage static......

thats the theory.....

Absolutely, so exactly my point. If you could vary current in real time instead of a corner height lock, you could stop varying torch height and vary current to achieve the voltage set point. You should keep the kerf width constant and part dimensions will be more accurate.

The alternate paradigm we can do now without hacking a plasma cutter is to offset the torch position along a perpendicular to the arc tangent (heading) so the increased width of the arc is compensated for to keep arc dimensions closer to spec.

phillc54 wrote: This topic is about the QtPlasmaC release, can we please keep it to that...

You must be scared we are gunna make more work for you! Take a well earnt break for a few weeks.