[Jacala]

Hello!

After building a laser engraver I'm thinking about a simple plasma tube notcher. The idea is to cut notches, specific holes and shapes out of stainless round tube.

But I've got a few questions.

when using a lathe chuck, how do you program the system that it knows the diameter? 1 inch is a big difference with a 3 inch tube. For 1 project one full turn is 150 mm and the next project it is (lets say) 300 mm. That is quite a difference in cutting speed. Simply lowering the cutting speed would not work because your cutting in 2 axis, also along the tube.

Why not use a rubbercoated wheel attached to a steppingmotor and rest the piece of tubing on that wheel. Then you automatically fix the diameter problem and you could simply make a 2d dfx drawing to send to mach3.

Example: Cutting a notch or shape on a 100 mm tube? simply draw a flat CAD drawing 314 mm (diameter*pi) high and that would be 1 full turn of the tube. Just scale the coping shape to the right hight and your done. Would it be that simple? This sound to me like a easy, understandable and easy to work with system.

I hope this is understandable, my English is not bad but the technical explanation is quite difficult. If not clear, I'll make a drawing.

What do you guys think?

[Jacala]

I was drawing and working with large tubes is difficult with a wheel, unstable etc.

So my preference would be using a lathe chuck like this:
https://www.youtube.com/watch?v=Dp0s6QqVCIk

could i use mach3 or something for this machine and how would i program it? Make a 2d dfx file and use that to create the cutpath? Thats no problem with solidworks. But how can mach work with different tube diameters?

[Jacala]

A day later: Tought about it and is this gonna work?:

Program Mach3 as a router, count the number of passes to the stepper that rotates the tube 360 degrees. lets say 500 steps for 1 full circle.

So for a tube with a circumference of 98 mm you program mach 3 as 500 steps = 98 mm. (a full circle)

The next project with a bigger tube you program mach 3 as 500 step = 150 mm (a full circle)

Than you would just load 2d images of the cut patch an mach would "think" that is is a plasma router.

In my head this could work but I'm not hold back by anny kind of cnc mach 3 knowlegde.

Is this possible?

I would love it!

[limekyle19]

Check out Tom's stuff over at http://www.candcnc.com/ he has a rotary tube slicer program that use's mach 3....this all can be done easily!

also check this out http://www.cnczone.com/forums/plasma...r_project.html

[Jacala]

Hello!

I've been reading and watched the mach tutorial on youtube. What a nice program btw.

By adjusting the steps per mm in the motor tuning part of Mach it would be very easy. (correct me if i'm wrong)

Once i know the number of steps for one 360 degree circle i can use excel to make a simple calculation program that gives me the right number of steps with each tube radius. Then a 2d drawing of the right size will wrap nicely around a tube.

Then again, is this correct?

[limekyle19]

As far as I know all you have to do in mach is enter tube OD and load your g-code and your off

[Jacala]

But how does mach know what one rotation is? Do you program that first?

[limekyle19]

Ya you program how many steps under motor tuning in mach and that's it