Put the 5mm shim in place to stop upward travel before it hits the acrylic top.
Then do ONE of the following:
- Get firmware source, edit configuration.h file, change Z_MAX_POS from 159 to 154, rebuild firmware and reflash. This will tell the firmware that it is at 154 instead of 159 when hitting the endstop, and that will allow the existing clean/wipe scripts to function correctly.
- Send the printer the commands “M206 Z-5” followed by “M500”. The first command offsets Z coordinates, which will effectively make the end-stop position 154. The second command saves the change to memory (otherwise it would be lost at next reboot). The next time you “home” the printer and it hits the endstop, the Z position will effectively be 154 instead of 159. Existing clean/wipe scripts will function correctly.
Either of those will compensate for the lower effective endstop position caused by the shim. All existing scripts will work – unless they command the printer to go higher than 154. Trying to go >154 would hit the endstop and be ignored.
If you choose #1… You’ll need to do it again if you want to flash a newer firmware from Lulzbot. Other than that, the change will “stick” permanently.
If you choose #2… You’ll want to check the offset if/when you ever flash a new firmware. The setting may survive a new firmware flash, or it may not (depends on firmware layout). If it doesn’t survive, you just need to send the “M206 Z-5” and “M500” again. Other than that, the change will “stick” permanently.