Hello Guest it is May 24, 2019, 05:39:42 AM

Author Topic: Plasma accel values, position accuracy and cut speed, servo tuning  (Read 1173 times)

0 Members and 1 Guest are viewing this topic.

Hi,

Im looking to get the views of plasma users on my set up/ tuning.

I have an old boc falcon which i have fitted up for cnc with mach, i have two 250w dc servos on the x and one on the y, whale drives from cncdrives.com driven with rack and pinion.

For anyone who is no familiar with the machinery it looks a bit like this

http://fplreflib.findlay.co.uk/articles/22842%5CESAB_refurbished_cutting_machine_main.jpg

My plasma is a hypertherm max 100

I have been asked to do a job in 3mm steel with loads of 3mm holes and slots and i told the guy im not sure but i wanted to try so i found at 1000-1500mm/min i could operate reasonably well at the proper cut speed 2000mm/min or higher the cut was hopeless, most lines look like saw teeth.

Really what im after knowing is do i have a problem i need to find or am i tryin to achieve something thats impossible? After trying some parts in steel i tried some on paper with a pen, with my aceel valu at around 15-20milli gee's the paths were pretty straight but at the 40-50milligees that people say you need for plasma the machine just resonates back and forth whilst cutting these small parts, but at the 15-20 value when trying to achieve 4m/min the machine never gets up to full speed when cutting the perimeter of a 50mm square, but the corners are perfectly square, is that a problem? When running these parts if i get the error viewer up for the x and y axis i never see more than what equates to 0.3mm error even under the highest acceloration so i was kind of thinking my motion looked good in terms of position error and the trouble was caused by mechanical resonance in the frame.

Where would a proffesional go in trying to improve this?

Matt