Help on a robotic plasma Cutting Design

[HiVac]

Hi everyone,

I have been tinkering with a project for several months, using a Asea IRB6/2 robot mounted to a 5 foot slider. This system whill be implemented in a plasma cutting table. I have designed and completed the 4' X 10' plasma table and the entire design was centered arount this robot / slider system. I thought this would be a good idea and a lot of fun, but now I am second guessing whether I should continue with the robot, or re-design the table to include a gantry system instead. The issues I have are with the software and implementation, and the acuracy of the slider repositioning. I have not purchased any software / hardware yet, but have had several conversations with Gary at Camsoft.

This robot will not completely cut the full width of the 4' sheet ( the length is fine ) but this is all we need.

I would like to include photo's of the system, table, and the robot, but I am not sure how?

If anyone hase some insite / or previous experience with something like this, your help / experience would be greatly appreciated.

 

[Barry1961]

A gantry is the way to go on a plasma cutter. The most popular design is the cam followers and rack and pinion method. Some of the newer upscale designs will use a dual belt drive on bridge and THK or Rollon type bearings. If you don't have a good machine shop go with Rollon type.

There are several places where you can buy CAD to G-Code software which makes life easy.

I would try to keep the inertia mismatch to 5:1 or less and a very stiff (kevlar) belt to drive it. Consider turning down the OD of you drive pulleys about .020" if you want a tighter fit. Of course make the moving parts lite and stiff if you want good sharp corners without making the extra triangle move outside of corners.

If you are going to cut thick material and want to adjust the tilt of the plasma's V cut so the part has a square edge it gets a little more complicated but gantry is still the way to go.

Barry1961

 

[Stupidav]

I have to agree with Barry, I recently built one, with one exception I used Ball Screws to drive the 3 Axis unit. I chose to go with Animatics servos and their JEN CNC Software package which simplified everything, especially the CAD to G-Code conversion. Using indicators we were able to maintain a repeatablity of +/- .00075. which was much better than we expected.

One thing to keep in mind, is that the cutting operation will generate heat, primarily raidant heat, that will be transfered into the structure, causing expansion and contraction. We had to implement some heat shields as well as run a small homing operation to reset the Zeros to ensure repeatablility.