First Steps with Path WB

Here's the place for discussion related to CAM/CNC and the development of the Path module.
sliptonic
Posts: 597
Joined: Tue Oct 25, 2011 10:46 pm

Re: First Steps with Path WB

Postby sliptonic » Thu Jan 05, 2017 4:19 pm

herbk wrote:Hi sliptonic,
in that time path WB produces gcode with a G00 X-1.0 Y1.0 comand in the postamble.
If i not change the X-1.0 to 0 (or higher), linuxcnc gives me a warning about a path over the limits.
You are right, i can ignore that. But if i do so, and have a machine setup like mine, where the mechanical limit is realy close to the softlimit i run in problems.

My machine (a router) works like that:
I switch it on and make a calibration run. This run sets the 0 pionts for X, Y, Z by runing on the limit switches. The way from touching the limit switch to the mechanicel "touch" is 1mm.
After changing the tool ( on my own machine i have to do manuell) i run the Z axis down to the table to set the touch off and back to 0.
The sheet of material is always placed on X0, Y0. So it's easy to place a new sheet of material and after changing the tool i have only to adjust the touchoff new.

Around me the most people working with router setups like this


Homing and touch-off are not at all the the same thing. It sounds like you are using the machine coordinate system (homing) as your work coordinate system (touch-off). This works but it it isn't very flexible. When I start my linuxcnc milling machine, I run the homing routine to establish the machine boundaries. This prevents the machine from crashing into its own end-stops regardless of what the gcode says.

Then I touch-off to establish o the X=0 Y=0 coordinates for the work piece. In linuxcnc, this has the effect of moving the gcode plot within the machine boundaries. When this is done correctly, negative XYZ coordinates won't give any warning at all.
herbk
Posts: 336
Joined: Mon Nov 03, 2014 3:45 pm
Location: Windsbach, Bavarya (Germany)

Re: First Steps with Path WB

Postby herbk » Thu Jan 05, 2017 4:31 pm

GeneFC wrote:All of this is purely arbitrary, but one must be consistent at all steps of the process. A crash will occur only if one does not take care to ensure that all the origins and setups are based on the same choices.


Hi Gene,
whith this you are right...
I think for the prefered machine settings there is also a different between a router and a mill, - and as you have learned it... ;)
Gruß Herbert
chrisb
Posts: 1668
Joined: Tue Mar 17, 2015 9:14 am

Re: First Steps with Path WB

Postby chrisb » Thu Jan 05, 2017 4:33 pm

sliptonic wrote:Not true. LinuxCNC/Machinekit handle negative XY values just fine. Negative Z as well. I routinely position my parts in the +X-Y quadarant so they align with the milling vise for touchoff.
Glad to hear that. I had already thrown my plan of a linuxcnc retrofit overboard, because I got accustomed to my workflow. And of course I want to have the coordinates which I have in FreeCAD in the GCode as well.
herbk
Posts: 336
Joined: Mon Nov 03, 2014 3:45 pm
Location: Windsbach, Bavarya (Germany)

Re: First Steps with Path WB

Postby herbk » Thu Jan 05, 2017 4:57 pm

Hi Sliptonic,
It sounds like you are using the machine coordinate system (homing) as your work coordinate system (touch-off).
yes, that's true, only Z i give a differrent 0 for work.

On a router i din''t think its less flexible as an other setup. For me (on my machine) it saves some workspace (of course only a few mm's, but if you have not to much...) and i dont have to make a X Y touchoff each time i put on a new sheet of material.
Gruß Herbert
jcf
Posts: 35
Joined: Tue Nov 15, 2016 10:34 am

Re: First Steps with Path WB

Postby jcf » Wed Jan 18, 2017 5:57 pm

I saw this topic only just now, but I am very happy about it, as it is just what I wanted to do myself.
As a beginner with FreeCAD I found it very difficult to get started with the path module (though in the 0.17 daily version it is very easier to understand).
chrisb
Posts: 1668
Joined: Tue Mar 17, 2015 9:14 am

Re: First Steps with Path WB

Postby chrisb » Fri Jan 20, 2017 1:44 am

jcf wrote:I saw this topic only just now, but I am very happy about it, as it is just what I wanted to do myself.
As a beginner with FreeCAD I found it very difficult to get started with the path module (though in the 0.17 daily version it is very easier to understand).

Glad to hear that it helped. Of course you are invited to add to the documentation but you should be aware that things are likely to change. And we won't stop the developers from creating great things only because it wouldn't meet the docs - would we?
jcf
Posts: 35
Joined: Tue Nov 15, 2016 10:34 am

Re: First Steps with Path WB

Postby jcf » Tue Feb 07, 2017 1:30 pm

chrisb wrote:Glad to hear that it helped. Of course you are invited to add to the documentation

I had started something here:
http://staff.ltam.lu/feljc/software/fre ... t_to_g.pdf
(I started from 2D, as I had problems with 3D generating a path and I thought maybe this would be more simple)
chrisb wrote: but you should be aware that things are likely to change. And we won't stop the developers from creating great things only because it wouldn't meet the docs - would we?

No, we wouldn't do that! :D
chrisb
Posts: 1668
Joined: Tue Mar 17, 2015 9:14 am

Re: First Steps with Path WB

Postby chrisb » Tue Feb 07, 2017 4:19 pm

Thank you for sharing your file, I think it is a good introduction to path (in it's current state). Many of the issues you mentioned are already adressed here, except that path doesn't work with plain wires. To be honest, I was surprised that it works with faces, because milling is in my view always something with a solid. This shows to me that the base constructs of path are sound and well integrated into the FreeCAD world.
As for viewing you might mention that you use the wireframe display mode. That is especially sensible if you want to see if paths lie inside of a solid.
rweait
Posts: 6
Joined: Sat Mar 04, 2017 6:01 pm

Re: First Steps with Path WB

Postby rweait » Sat Mar 04, 2017 6:43 pm

Thank you for this documentation for Path WB. I'm new to FreeCAD and was struggling with the learning curve.

Tools do not yet appear in the tool library, for me. I've tried switching back and forth from <Main> -> Job -> <Main> and double clicking the same, as suggested in earlier posts.

I'm running freecad-daily, updated today.

OS: Ubuntu 16.04.2 LTS
Word size of OS: 32-bit
Word size of FreeCAD: 32-bit
Version: 0.17.10410 (Git)
Build type: None
Branch: master
Hash: 404debb9f2b05991b93c77fbb0f29e12257e4a83
Python version: 2.7.12
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17

I followed the steps from the first post, as far as I could. I created two end mills, with diameters, but they did not appear on the tool library list.

What is the filename of the default tool library file? In which directory should it be? I wasn't able to find that in a quick look at the code on github.

Thanks for all of the wonderful things in FreeCAD.
chrisb
Posts: 1668
Joined: Tue Mar 17, 2015 9:14 am

Re: First Steps with Path WB

Postby chrisb » Sat Mar 04, 2017 11:24 pm

Can you create a screencast and upload it to a video streaming service? Post the link here and I will have a look at it.