Messages

1

General Mach Discussion / Re: Plasma cut quality problem

« on: September 26, 2009, 11:24:32 PM »

Thanks for trying to explain things a little more. It's been a steep learning curve to say the least. I'm new to Mach3, New to Plasma cutting, and this is my fist machine to build. Servos, controllers, power supplys, electronics....  my brain is almost shorted out. I've been on this project for a little over 2 years and just now started cutting parts.

Take Care, Aj

2

General Mach Discussion / Re: Plasma cut quality problem

« on: September 26, 2009, 09:45:06 AM »

As it turned out I finally hit the nail on the head. The guy from CandCNC - (Tom) pointed me in the right direction.

He told me to turn off all selections in "General Config" "CV Control" and make sure that "Motion Mode" was set to "constant velocity".

I did that without and change in cut quality.
 
Here's the trick.....  I had to use the "1024" screen, which I didn't have a clue about, go to the "settings tab" and turn off "CV Feedrate" .  CV Distance, on or off didn't seem to make a difference with any of my problems, so the question remains on whether this should be on/off and what value it should have.

I instantly saw the improvment in machine motion.
 
No exaggeration - my machine will run 4 times faster on that little 4in part and without any vibration or shaking... 200in/min
 
Now I'm in business......
 
That CV Feedrate setting should be on the "plasma screen" if it's that important.
 
Thank you guys, I'll talk to you later.

Aj
 

3

General Mach Discussion / Re: Plasma cut quality problem

« on: September 25, 2009, 07:07:17 AM »

Mach, is in CV mode.

I'm going to give adding G-64 a try today.

I don't really have any backlash. I had another problem in the past when I just got the machine up and running (two months ago) and spent a good while checking backlash. The backlash has to be less than .001.

The machine has good repeatability and accuracy..

I don't want to be quick to say everything is perfect like so many, because I do have a cutting problem.

The notches don't show up on any other shape, even 45deg cuts. They only seem to serface on the 3 point arcs or ellips and line up with the nodes in the drawings. The hessitation can be seen with the eye at the end of the arcs. The arcs don't show a big change in direction. I could understand a sharp turn because of deceleration, but this is basicly going the same direction.

There's no doubt - The job is in the details!

Thanks for the suggestions, Aj

4

General Mach Discussion / Re: Plasma cut quality problem

« on: September 24, 2009, 08:26:59 PM »

I should of added the .dxf file just in case.

Aj

5

General Mach Discussion / Plasma cut quality problem

« on: September 24, 2009, 08:07:22 PM »

Hello, I've got a plasma cut quality problem and just can't get to the next step with it. Progress in all areas except for this. See attached photos. I've got some hesitation in arcs. No problem in circles, squares, triangles, or lines. Just at the end of one arc and the start of another arc, like in the 4in fleur-di-lis. Maybe a 15 - 20ms hesitation, just enough to see when the machine is running at 50 to 60in per minute. The faster The machine runs, the more outstanding the marks become.

I've got good repeatability to about .0005 - .001 and have good accuracy. I've worked on the motor tuning / velocity, and speeds till I'm at my wits end.

I'm using autocad 8 to make the drawing, save as a .dxf, import into sheet cam to post. I don't believe it's mechanical because of the time I've spent. I believe it's in something I've got wrong in Mach or it's the way I'm making the G-code.

Any suggestions would be greatly appreciated. I've been hammering on this problem along with other things for about a month.

Thank You!  Aj