Welcome to LinuxCNC.org

If because of the questions I pose I am in the wrong forum, please let me know and and I will re-post.
I have a home built 3 axis machine running LinuxCNC 2.5.0 with limit switches installed on all three axises and using a combination limit/home switch configuration. My question concerns homing and offsets from the home position. I use the machine mostly for doing engraving and want to do multiple objects one after the other. When I home the machine (using the limit switches), and then execute the Gcode, the first iteration works fine. Then when I put the second workpiece in the fixture to hold it for engraving. When the same Gcode is executed again, the cutter moves to a location that is offset in all 3 axises unless I close and completely reset LinuxCNC. Checking the offsets shows that there are now work offsets in the register. I am not using any G53, G54 or G92 commands or tool compensation commands in my programs (yet).

Question.. How.can I get the machine to automatically return to the home position at the end of a program?
Question...Can I do this using the limit/home switch configuration?
Question... If X0, Y0, Z0 are my mechanical stops as determined by the limit switches how do I properly configure for the soft home and normal home coordinates?
Question...How do I prevent the machine/code from automatically setting work or fixture offsets?

What I want to do is set up the machine, run the program, install another work piece and rerun the code for the second and subsequent pieces. As hard as I try, I have not been able to get this to work properly. Even though I am not (intentionally) using offsets,I believe that my problem is caused mostly by improper set up of the home, safe limit and perhaps coding of some of the initialization parameters.

Any guidance to point me in the right direction will be greatly appreciated since this is my first experience with CNC and I feel like I am in way over my head.
Thanks,

Bill

If you can attach your ngc file maybe we can spot the error.

My first question is are using absolute or relative moves?

To return to the machine home G53 G0 X0 Y0 Z0 will put you back at the machine origin (home position).

John

My second question is are you using CAM generated G code?

John

John,
thanks for taking the time to reply.
I have attached the test file that I am using. The code is generated for me by Stickfonts and is all absolute moves. I have tried putting a G53 x0 y0 z0 in the front of the file but it did not seem to help. I still feel that my problem has something to do with my setup.

Bill

Sorry but I had to change the file type in order to attach my test file. It is attached to this message.
Bill This attachment is hidden for guests. Please log in or register to see it.

your test file is missing initialisation values and specific setup details
which for example cancel work offsets etc , set up modes etc .

i'll re do your file and post an update as an example in a few mins , which will show you good practice
an excellent book is ' cnc programing handbook by peter smid ' just about covers every aspect it's worth a good read