Hey! This thing is still a Work in Progress. Files, instructions, and other stuff might change!

Lulzbot TAZ retractable Z-probe auto bed level compensation with G29 Mod

by 1013 Jul 14, 2013
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Very nice job!!
The link for firmware on instructions don't work is it any possibility you can provide working link? :)

This is great, any chance anyone has some working G-Code for a Lulzbot TAZ 4? I've searched and got it almost right, however it deploys fine, probes 4 corners (my preference), retracts the probe, and then tries to print an inch over the bed (basically the height of the probe to the bed). I'm sure I'm missing some type of temporary Z-probe offset function. Would be great to see what others have out there working. I'll post mine once I have a working example to share or if someone wants to see what I have PM me and I'll send it over. I don't want to add to the confusion by posting G-Code that's not work 100% here. I have combed through the G-code reprap wiki and found some great stuff there, however I am new to 3D printing and not sure what I'm missing. Any advise would be awesome. Thanks!

heres what id do...
G28 XY
G1 Z30; Rapid movement Putting z position somewhere above the bed and objects on bed if any
G1 X205 ; The 205 is max x position that deploys probe ...change it to whatever your probe needs to be at in x axis to deploy
G28 Z; Home z (the bed center is All axis zero in this case so the carriage moves to center bed in xy before probing z home)
G29; probe bed after homing axiis
M500; save g29 probe settings to eeprom
G1 Z30; raise z to Safe area above bed again
G1 X5; Far enough to retract probe but NOT far enough to bump endstop because you may end up losing all probe findings from previous G29 depending on firmware setup ect.
then run the rest of your startup code and be sure to change it if it conflicts with the probing code above ...and dont forget---> verify that the gcode looks right. load it up in cura or whatever software you have that allows you to view layer output first before you click print and save alot of headaches and time.
I actually use a rack type system to deploy my probe and this is how i do it. I wish i understood marlin functions better so i could change g29/g28 coding to include the deployment and retraction of the probe before/after g29 or g28 when it is called upon, then i could flash it to firmware permanently and do away with the startup gcode.
Anybody out there got any idea how i can change g28/28 code to include the probe deploy/stow in marlin?? thanks in advance

anyway neotype33... i hope this helps

I also have a Taz 4 and have made these parts. Please post your G-Code when you have it working. Thanks!!

Great project. I've made all the parts, but can't get to the firmware code. I get a 404 error. Can you repost, or direct me to the source? Thank you

On Matterhackers we are told about an all software bed leveling method.
Is this hardware one still relevant or should I explore this software only solution ?

I ve just printed the x stiffened mods. I wonder if I should print pieces for this retractable probe :-).

I love this! Well done.

I wish my printer had this mechanism on it. We would love to work with you to get MatterControl working with this setup probe. Do you have a branch of the firmware that makes it move to the side rather than the up motion?

i have not modified the firmware (besides the config file). The moving to the side to deploy and retract the probe is all done in a custom G-code that is run at the beginning of each print. and this is of course slightly custom to each machine. If you could setup a G-code script to run as a "probe bed" command, instead of a simple "home-Z" command...that would work. Maybe an option to run a G-code program in place of the home-Z command.