I'm not sure what's wrong with my lead machine. The GRBL settings are saying lead1010. The hard limits work just fine and I can home and zero on the work piece just fine. Then when I start the job the Z axis, which always goes up, starts the router, then go down into the work piece, is now acting crazy. It just goes straight down and slams into the work piece no matter where it's located. What's happening!
Did you "set zero" relative to stock? Homing sets Machine Coordinates. But jobs run in Work Coordinates that is set using G10 L2x commands / set zero buttons
Yes I did. Then to go back to the zero point so I can set a new Z zero for a different tool I used the "set predefined position G28.1"! It was the first time I did this cause I'm tired of jogging to the zero for a new tool. Not sure if that caused the problem.
Switching between coordinate systems (without a deeper understanding) may well contribute to the crash, for sure. All offsets in Grbl are relative to mPos. Moving in the correct WCS is important as is setting zero in the correct systems. Homing is the only way to set mPos
I am trying to set a position for a touch plate and I just can't make it work right. I placed the touch plate at a certain spot on the table and was trying to figure out how to get the axis to move to that location relative to the home point for tool change and probe the Z. I tried the G53 in a macro but when I give the command "G53 X200"! I expect the X to move 200mm from the home point. It just keeps going right indefinitely! Do you know what's the problem and why G53 is not working? And do you have a macro for this?
Homing your machine is not the same as G53 being X0Y0Z0. For an explanation, refer to the " Why is Grbl in all negative coordinates after homing? Or it so annoying and not what I'm used to!" section of the grbl faq here: gnea/grbl Basically GRBL machine coordinates is always negative. So, lets say you have your homing switches in the lower left of your machine. And lets also say that your X has a maximum travel of 1000mm. When you home, your spindle will be at G53 X-1000 (+ whatever you have set for pull off). So if you wanted to move 200mm in X from machine home, you would use G53 X-800. (1000mm max travel - 200mm). So, thats why you should use G28.1 instead. Peter has some menu items for doing this but I preferred to set up macros so I can have everything on one screen. My G28 moves from job to job, so I set up one macro with a simple G28.1 command in it. To use it, I jog to where I want it to be for that particular job and click the macro. Then I set up another macro to move to G28. There's a few ways you can approach this. If you issue a simple G28 command, all axis move at the same time which can potentially lead to a cutter crashing into a clamp or stock or whatever else I have laying on the table. So, I instead move Z up to -10 below my limit switch, then move to G28 X0 Y0, Like this. Code: G53 G0 Z-10 G28 OBVIOUSLY NONE OF THIS WILL WORK IF YOU DONT HOME FIRST
After I home my machine, I have to click on "Zero XYZ" button. After I use "Probe Z0" tool, I click on "Goto Zero XYZ" button before starting a job.
Thanks for explaining how the G53 works. Yes I had few accidents with G28. So I appreciate the advice.
