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« on: September 13, 2015, 01:12:59 PM »
Dave, (;-) It would seem you have an accel issue IF you are getting corner rounding. Plasma depends on a constant as possible cutting rate . Turning OFF CV anywhere defeats the purpose of CV. I plasma cut just about everyday from 28ga up to 3/4",steel and aluminum.
A lot of what you are talking about in corners is a THC problem where it is NOT holding the height as it slows down. THAT is a setting you need to play with. Start adjusting the anti dive/corner dive in Mach3. IF it is to much reduction in vel before it locks then you get a arc that is to low and THAT will angle the kerf . You want the anti dive to lock out before it effects cut quality.
Another issue is using the correct combination of Nozzle, Sheild. air pressure, amp settings, DRY AIR. This are very important to cut quality as well. Get one part off and the quality goes down the tube.
with Plasma a LOT can be said out the quality of the Cut file. You are much better of with radiused corners where ever possible. A sharp intentional corner makes it HARDER for the machine to maintain a constant cutting speed(almost impossible) without rounding. Accel is king with Plasma cutting and well as a very lightweight rigid gantry. Motros are calculated for max acell properties (low inertia High torque) THEN comes speed. Most times steppers have limited RANGE of operational speed where as Servos have a much wider RPM band they can work in.
THCs are another can of worms for most DIY users . BUT that is a different chapter in the " So you want to be a plasma cutter book ". (;-)
NOW IF your control cannot do transitional changes in Gcode without a HESITATION then you have a Controller problem. There ARE controllers that do not have that problem. Another chapter in the book. The trajectory planner has to be top notch and very much in control without hesitations in execution.
I use the STANDARD Mach3 CV with NO adjustments at all. JUST like it comes out of the box and it cuts fine detail very well here. I do a LOT of artsy stuff where DETAIL is an issue. NOW that siad I also use an alternative cutting speed settings for the very thin stuf <18ga . I am not interested in trying to cut above 200 IPM . There is ALWAYS an alternative cutting solutions to high speed cutting, you just have to find it
You are trying to solve a mechanical issue through software control (;-).