UPDATE-Video of Taz Auto Bed Leveling Mod Based on Taz Mini

Here’s a video of my Taz Auto Bed Leveling Modification. I based it on the Taz Mini. The bed corners are made out of ninjaflex and I added a Z-Max endstop to the printer. I used slotted shims to secure the bed to the corners. I attached a ground wire from the Z-Min endstop to the bed plate mount and I attached the endstop’s signal wire to the hotend. The wire on the hotend runs up to the extruder and heater/thermistor connectors where it connects to the extruder harness. Both of these wires have quick disconnect molex connectors in case I swap tool heads or if I want to remove the bed. This was just a prototype to get dimensions for the bed washers. Right now I’m in the process of making custom washers on my cnc. I also enlarged the wiper mount from the Taz Mini and attached it to bed plate. It barely fits on the bed plate so I’m in the process of designing a new bed plate or wiper mount. You can see a video of it probing and cleaning the hotend here: https://www.youtube.com/watch?v=Hx1q_GJC3_k&feature=youtu.be

If anybody is interested in the STL’s for the bed corners and the Z-Max endstop holder let me know and I’ll post them on Thingiverse. Also does anybody know if it’s possible to use this type of auto bed leveling without having to use a Max-Z endstop let me know.

Cool! :slight_smile:

Hello, that implementation of bed leveling on the TAZ is awesome.

I would like to implement that on my TAZ 4 also. Can you let me know what components I need to do this and point me to the instructions on how to implement it? Can it be done with the Dually Extruder on board ?

Here’s my updated design. I made custom washers and a bed mount plate that’s based off the Lulzbot Mini. The new design uses the same bed corners as the mini. On the bed mount plate I had to move the back bearing holders and the belt mount forward a little so that the nozzle could reach the front washers. You can see in one of my pictures that on my first attempt I didn’t do this so I had to make bigger washers for for the front corners. This design is more accurate than my first design with the shims. I’m still working out the gcode for the wiper. I’m also experimenting with this marlin firmware enhancement that lets you save the G29 bed level correction matrix to EEPROM so you don’t have to perform a G29 before each print. You can find the G29 enhancement here: http://3dprintboard.com/showthread.php?8064-Saving-G29-Bed-Level-Correction-Matrix-to-EEPROM

Out of all the different ways I used to probe the bed for auto leveling this has to my favorite. You don’t have to worry about X and Y probe offsets since your using the hotend. Plus I can still use multiple toolheads like the flexystruder, My hexagon hotend and my latest e3d valcano hotend.

I have to give credit to Lulzbot for creating this unique way to level your bed. They have really outdone them self’s with this one.


What you have done is awesome if one has a flat build surface.

Unfortunately my build surface is not flat. I used this technique to verify: http://www.thingiverse.com/thing:551366

It turns out the distance from my hot end to the center of the bed is 0.15 mm shorter than the distance from my hot end to any of the corners of the bed. It could be due to the weight of the dually causing the x-axis to bow when its hanging in the center or because the glass is bowed up in the center; either way the center is short compared to the corners.

Do you have any ideas on how to compensate for this?

I would try using one of the probe methods that I mentioned in the other post. When using one of those probes you can have Marlin probe the bed in grid pattern and you select how many spots it probes. So if you could select nine probing spots and it will then probe the corners and five other spots on your bed. I don’t know what the max number of probing spots is but I know it’s more than nine. Auto bed leveling should be able to fix your issue even if it is just the x rods bowing in the middle. One of the main reasons people use auto bed leveling is they are unable to manually level their because of problems like you described.

Would you be able to post the STL’s for the bed corners please? I have the custom washers on order from lulzbot and already have the extra endstop and mount. I have started on the firmware as well, so any help you could give me with that would be greatly appreciated. So far i have copied the Auto bed levelling code from the mini firmware, and just need to work out the probe positions to hit the washers.

When you replaced your bed plate with your custom machined one, did you notice if your original one was bent? its just i seem to have about a full 6-7mm higher front left corner than the rest, and was curious as to what caused it.

OK, I should have looked further before I posted my question about upgrading the TAZ to a Mini style bed scanning.

But I have a question. Even probing 9 (or 90) points from the bed the firmware will use 3 points tocreate a Z plane; is that correct? if so then what 3 points?

Just wanted to mention that,autobed leveling won’t resolve a warped, bowed bed. Autoleveling simply establish a plane for printing and constantly adjust z-axis to stay on that plane. Only three points are required to define a plane. If more points are sampled, a better “averaged” plane could be established… so if a few of the extra points fall in the bowed area of the print bed, it could potentially compensate for the droop in the middle of the bed. But ultimately, the project will never be completely flat… .15 will never be detected, but .15 is a lot for first layer adhesion.

The grid in which the bed is probed is defined in the firmware as seen below, these values can be changed in order to compensate for your bed size:

Does anyone know a reason why this couldn’t be applied to an AO-101?

Hi Techsavvy, mind posting your firmware? I’d love to take a look! Thanks.

The bed corners on the AO-101 bed frame aren’t the same as the TAZ and the Mini, so you would probably need to design something with the washer offset so it wouldn’t take up as much of the bed. Aside from that, you would have to tinker and reflash the firmware a bit, but all the necessary ports and connections are there. You might also want to upgrade the hot end first since the buddaschnozzle might not have sufficient electrical connectivity for the sensor to work the way it does with the hexagon one. That’s just a guess on my part though.

I just wanted to make a comment about “levelness”. I help quite a few folks setup their printers (of various types). I’ve learned that there is a big potential for warping the bed with a >3 point attachment system. For instance, on the Rostock delta printer the heated bed and insulator are attached with 6 screws to the frame. It is very common to introduce a warp or bend. Simply attaching at 3 points almost guarantees that you will not introduce a warp and if your bed is flat, it will be level. 3 points defines a plane, any more than that and unless you are very careful, you can introduce a warp. The 4 corner mounts of the Taz and mini can be problematic.

The best thing to do is to measure the flatness of your bed off the printer. Borosilicate glass is pretty darn flat (especially for the price). Use a very straight metal edged ruler and check for gaps when it is held against the glass in various spots (use a feeler gauge). If it is indeed flat, which it most likely will be, then mount it using 3 corners and test again. Next, use the 4th corner and recheck and see what you find. Finally, carefully level the bed and be careful not to turn any one of the corner screws too much as that may introduce a bend/warp. It’s a bit tedious to do this with a 4 corner attachment but critical if you want a flat bed.

Nice advice! :slight_smile:

KCCHEN_0 is correct, I will also mention some owners in the forum have found there to be a few thousandths of an inch sag in the middle of the horizontal hot end carriage system due to minimal bar sag, compared to the outside ends. Good Luck, an happy printing!