X origin error when machining

Hi,
I have done some experimenting today and have noted the following

After starting the Router program, the first time the file is opened you can see an approach tool path starting from the right of the correct start point. (see curser on screenshot1).
If I open the file again it only shows the correct start point (see curser on screenshot2). This is the same if I open the file again.
I only get what you see in screenshot1 if this file is the first file I open after starting the router program.

Screenshot3 shows what happens I start machining process of screenshot1. The tool travels toward the correct start point then the display quickly moves to wrong start point at the right, but the machine does NOT travel for the portion shown in yellow (at curser). This is where the 35mm X axis off set is coming in as the machine travels back to what is meant to be the correct start point (in this case milling an unwanted groove as it goes!)

Screenshot4 shows the same error showing on a different file. Again if I open the file a second time it opens with only the correct start point.

The files that have shown the radius error respond like the above. If the file is opened the second time the error does not show.

Aciera question
“If you do an MDI command G54 G0 X0 Y0 does the machine move to the right position (in your case the center of the part on the machine table)?”
It is the center of the part when before I start machining.
Once I start machining and I see it is not in the right place and stop the program, if I do G54 G0 X0 Y0 it goes to the center of part on Y and 35mm to the left of center on X.

Aciera question
“Where IS absolute zero (G53) on your machine? Is it in the lower left corner?”
G53 g0 x0 y0 takes head to right hand top corner. But I home to the left hand bottom corner with X home position = -1550 and Y home = -850

Tommylight advice
“Check if you have any offsets active.
Radius error is due to tool being to big for the radius being cut or when starting from an arc.”
The only off sets I can see are to do with height clearance etc

I did try removing the G53 lines on the door file and it made no difference.

Regards
Trevor

Ok so you get an offset of 35mm in X when you do a G54 G0 X0 Y0. This looks very much like an active offset: linuxcnc.org/docs/html/gcode/g-code.html#gcode:g92

When you get the 35mm offset in X after G54 G0 X0 Y0 does the DRO show X 0 or X 35?

Try this: MDI command G54 G0 X0 Y0. If it does not move to the center (ie you get your 35mm offset) do MDI command G92.1 (this removes all G92 Offsets) and try G54 G0 X0 Y0 again.

Note what is happening in the DRO for the X axis does it read 0 or not.

[edit]
Maybe also have a look in the linuxcnc.var of your config and check that parameters 5211-5219 are zero.

Just noticed that your gcode files start with '%'.
Is there a reason for that? No idea if it makes a difference but maybe try without it.

Aciera wrote: Just noticed that your gcode files start with '%'.
Is there a reason for that? No idea if it makes a difference but maybe try without it.

All of my gcode files begin and end with % sign, that is required if there are no M codes to mark the end of gcode file.

Ah, I thought it was only needed at the end. Thanks for that info

Hi Aciera,
See replies by your questions

When you get the 35mm offset in X after G54 G0 X0 Y0 does the DRO show X 0 or X 35? **Shows 0 , Have to go G0 X35 to go back to original position**


Try this: MDI command G54 G0 X0 Y0. If it does not move to the center (ie you get your 35mm offset) do MDI command G92.1 (this removes all G92 Offsets) and try G54 G0 X0 Y0 again. ** No change to position or DRO values**

Note what is happening in the DRO for the X axis does it read 0 or not.

[edit]
Maybe also have a look in the linuxcnc.var of your config and check that parameters 5211-5219 are zero. ***These are all zero. Only 5221-5223 have values***

Attached are a few more screenshots. The following is the order of actions before taking each screenshot.

Started Axis program
homed all axis
G54 G0 X0 Y0 to get back to where we had been experimenting
Touched off each axis X Y Z just to be sure.
Screenshot F

Started file executing. Machine moved to the wrong start point
Stopped execution after 2nd corner
Screenshot G NOTE the TLO X: -35.707. This is the same value that shows in the bottom of the radius error messages I have been getting.

G54 G0 X0 Y0
Screenshot H

G54 G0 X35 Y0
Screenshot I

Touch off X
Screenshot J

Opened file again – Display stayed the same as J

Started file executing. Machine moved to the correct start point
Stopped execution after 2nd corner
Screenshot K (DRO values for all the G54 lines and TLO lines stayed the same)

What does TLO X: stand for?
The versions of software I have are Xfce 4.8 and Axis 2.7.0