FreeCad - Path - Gcode - linuxcnc help with coordinate system

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mru
Posts: 14
Joined: Fri May 17, 2019 5:55 pm

FreeCad - Path - Gcode - linuxcnc help with coordinate system

Post by mru »

Hello,
I need help to figure out missing steps to change coordinate system or to make changes in my workflow. Im using Freecad and LinuxCNC
1. How I use to work:
1.1 Create part
1.2 Create Job
1.3 Set Origin in left lower corner (same as machines home position)
before.png
before.png (19.07 KiB) Viewed 746 times
1.4 Generate gcode (parameters --line-numbers --preamble "G17 G90 G21 G64 P0.5 G40 G80 G49")
1.5 move Gcode to linuxcnc
1.6 home machine
1.7 place part in 0;0 position
1.8 mill part

2. Now i have run in to problem and my solution steps are:
2.1 Fix part
2.2 Edit Job
2.3 Set Orgin on part where I can make reference
after.png
after.png (16.93 KiB) Viewed 746 times
2.4 Generate gcode
2.5 move Gcode to linuxcnc
2.6 home machine -
2.7 move to reference point on part
2.8 mill part

What I need to do or where to look?

PS. Please, point out the incorrect use of terms
Last edited by Kunda1 on Sun Jul 24, 2022 5:02 am, edited 1 time in total.
Reason: fixed typo in thread title
GeneFC
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Joined: Sat Mar 19, 2016 3:36 pm
Location: Punta Gorda, FL

Re: FreeCad - Path - Gcode - linuxcnc help with coordinate sistem

Post by GeneFC »

mru wrote: Thu Jul 21, 2022 11:18 am What I need to do or where to look?
I am not completely sure about what you see as a problem. In any case, I would move the "Model" in the Job portion of the FreeCAD Combo tree.

You can move the model anywhere you want. Just adjust in x, y, and z until the origin looks correct for your shop.

One problem I have seen on the forum is that sometimes people are looking at the solid that is in the top portion of the Combo tree. Make sure you are looking at the "Model" in the Job section.

You should recompute before creating the g-code output.

Capture.JPG
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Gene
memfis
Posts: 586
Joined: Tue Nov 15, 2016 7:58 pm

Re: FreeCad - Path - Gcode - linuxcnc help with coordinate sistem

Post by memfis »

There are several simple ways -

1. the simplest. You know which corner is 0. You turn on the machine, clamp the workpiece in the right place. In manual mode, you bring the cutter to the right place (where you want to see the angle). Zero the X and Y coordinates of the machine.
2. Make a small addition to the program code, like this
G10 L2 P0 R0 X0 Y0 (zeroed all offsets)
#<_dx> = 0 (offset)
#<_dy> = 0
#<_dy> = 0
G10 L20 P1 X[#<_x> + #<_dx>] Y[#<_y> + #<_dy>] Z[#<_z> + #<_dz>]
3. similar to item 2 -
G92.2
G92 X[#<_x> - #1] Y[#<_y> - #2]
#1 and #2 are the corresponding offsets
mru
Posts: 14
Joined: Fri May 17, 2019 5:55 pm

Re: FreeCad - Path - Gcode - linuxcnc help with coordinate sistem

Post by mru »

Because of PEBKAC problem I was not able to line machine and Model-Body in same spot and run into issues not worth mention.
However by doing so I start to look in G54 command and by using LinuxCnc interface button - Touch off I finished work.
Basically it all boils down to - read the manual - http://linuxcnc.org/docs/html/gcode/coo ... ate-system

Thanks GeneFC and memfis for support
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