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New program for pipe coping
« on: January 08, 2011, 11:07:55 AM »
I am writing a VB stand alone program to write g code to cope or notch pipes with a rotary axis plasma machine. I've attached a file (I think) to explain how it works. I don't have a machine up and running yet for this application and would like to try it on some Ginny pigs like you guys-- LOL. If you would send me the parameters for your jobs I will send you a g code file to try. After reading the attachment I'd appreciate any suggestions or comments on how I can make this better. Once I get it working I'd like to make a Mach wizard out of it.

Thanks,
Tony
« Last Edit: January 08, 2011, 11:18:47 AM by Tony Bullard »

Offline BR549

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Re: New program for pipe coping
« Reply #1 on: January 08, 2011, 11:50:04 AM »
 One problem you WILL run into is making sure that mach will sync up the feedrate based on the radius of the tube you are cutting. IF not you have a mess. SO in your code MAKE SURE there is a Macro call that updates the Radius correction DRO.

ALSO make sure the operator UNDERSTANDS that mach must be setup for 4th axis roatations in the proper plane for the toolpath AND that radius feedrate corrections are turned on.

There are already programs that can output DXF or Gcode for tube coping. NOT to cool your jets but to let you know(;-)

Waiting to see what ya got, (;-)TP
Re: New program for pipe coping
« Reply #2 on: January 08, 2011, 12:51:31 PM »
Thanks TP,

All really good points. Writing the macro and calling it would be easy but I'm not sure from a stand alone program how I'd get the macro into the machines correct profile macro directory. I guess if I had it as a plug in or wizard that might be easier but right now I wouldn't have the vaguest idea of how to write one.

I guess if there's programs out there that every-ones happy with I might as well leave it alone.

Thanks again, Tony

Offline BR549

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Re: New program for pipe coping
« Reply #3 on: January 08, 2011, 01:09:48 PM »
HECK give it a whirl, we can always work out the particulars.

Like the old addage says , THE operator MUST be responcible for something(;-)

Let them place the macro in the proper spot(;-) IF they want to use it I BET they can figure out where to place the macro(;-)

Setting up mach to do 4th rotations is just a simple setup process they can figure it out

Have it do the angle cope AND a hole placement on the base tube. Those are the 2 normal processes done. The hole placement being the most USED.

(;-) TP

Offline DaOne

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Re: New program for pipe coping
« Reply #4 on: January 08, 2011, 01:21:46 PM »
Can also just substitute Y axis for A so you can just unroll it on the tube. this will allow much cheaper cam software to work with this setup. 4th axis jumps up in price fast.

Offline BR549

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Re: New program for pipe coping
« Reply #5 on: January 08, 2011, 01:49:41 PM »
One problem with the wrapper approach is a hole that is wrapped and a hole that is projected are2 different dawgs as far as hole shape is concerned.

When plasma cutting on a tube the shape must represent a projected hole onto the tube being cut. It ends up oval shaped if you do it as a wrap.

If you look in the Mach tool box there is a simple coping routine that is driven with Gcode and a programable front end. It only does simple on axis angles not offsets.

Still working on the math to get perfect holes in a tube(;-).

I am sure IF you build it they will use it. That is one tool that is lacking in most DIY Plasma users toolbox.

Just a thought(;-) TP

Re: New program for pipe coping
« Reply #6 on: January 08, 2011, 02:43:50 PM »
TP,

I like this part "THE operator MUST be responcible for something(;-)" LOL
If they're going to file the macro they might just as well set the Radius correction DRO. instead.

"Still working on the math to get perfect holes in a tube(;-)."-----  Me too! I know I have the math perfect for the cope.----- I think.

DaOne, "Can also just substitute Y axis for A so you can just unroll it on the tube." The torch has to be perpendicular to the tube axis so either the tube or the whole torch has to rotate--- right?

Attached is the same sample code as the rotary but it is for wrap around. notice the X moves PI x D.

Offline DaOne

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Re: New program for pipe coping
« Reply #7 on: January 08, 2011, 02:53:32 PM »
Would sure be a nice addition to the end of our plasma table. Right now we use a tubing notcher to fish-mouth tubing before we run it on the mandrel bender. It works but would be quite a bit faster on a plasma cutter.  Most everything is tig welded so the better the fit the better the weld. The torch on our table come past the end about a foot so I was thinking about using a big chuck with a servo a while back. Just haven't gotten around to it yet. With us almost everything is a common angle and 2 1/2 is basically 98% of the work. If you guys are interested I could right a wizard to spit out common angles for common tubing sizes if someone could generate the g-code for it? Math involved to create it in the fly is beyond me.

Offline BR549

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Re: New program for pipe coping
« Reply #8 on: January 08, 2011, 02:57:41 PM »
It is one thing to just place a macro to drive the dro update as that is a ONE TIME thing(;-)

I like the auto update of the DRO as it takes one more step away from the operator to have to remember. IF you get it wrong the displayed toolpath will be distorted as well.  At least it does here(;-)

DOn't give the operator too much control he will think he actually runs it. (;-)

(;-) TP

Offline BR549

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Re: New program for pipe coping
« Reply #9 on: January 08, 2011, 03:14:40 PM »
Look at the simple coping routine in the MACH TOOL BOX in the download section. It works here for simple things.
There are 4 inputs it asks for the coped tube diameter the Base tube Diameter  the Tube thicknes and the angle of the cope.

In setting up a 4th for tube cutting consider using drive rollers to rotate the tube and run the A axis as a linear drive. One you set the steps per inch then it is just like runing X/Y  no polar conversions needed. The tube surface speed will always be the same as the surface speed of the roller driving it(;-).

Just a thought, (;-)TP