Even BLTouch Probe Can't Make My TAZ Print Flat

Installed the BLTouch on my TAZ 5 per this thread in our Forum: https://forum.lulzbot.com/t/taz-5-bltouch-project/5227/1 because I could never get a perfectly flat layer across the build surface from the first day I bought my printer.

Even the BLTouch probing 25 points can’t give me a good first layer across the build plate. The 2 small rectangles at the front of the bed look nice, but take a look at horrendous rectangle at the back of the bed. Perhaps the x offset 32 mm and y offset 30 mm of the BLTouch probe vs my hotend are the reason why the BLTouch can’t give me a good plane, but that would only be if the bed undergoes a ridiculous change in slope within 30 mm. Any ideas why my TAZ 5 bed is so whacked out?

Thats disappointing…

So when printing does the Z steppers move consistently to account for the print plane?

Yes, I watched the little aluminum barrels attached to the z-rods rotating a smidgen as the rectangles were printing and the aluminum barrels started their rotated print position at a very noticeably different spot when the back rectangle started printing vs where the front rectangles stopped printing on the same layer.

It appears that if your bed is relatively flat to begin with the BLTouch will give you a good print plane, but if your bed is whacked out like mine has been on my TAZ 5 from day one then you need to use the nozzle to probe the bed (not just at the corners) or maybe have the BLTouch much closer to the nozzle than what other people seem to be doing judging from the thread I referenced above (I copied them and got my disastrous results).

I’m going to try to get Mattercontrols or Marlins old fashioned yellow-sticky-slide-test bed leveling going and see if I can get consistent results that way.

I’d like to use an auto bed leveling system if I could find one that would work on my bed.

Well… check that the frame is square and the machine isn’t shifting when the bed moves. Also dial back the touchpoints… 25 seems like a lot. Start with the 3 and go up to 5… could be some bug in Marlin averaging all the touchpoints.

The machine is square, I checked it with an angle and watched it to make sure it doesn’t move while printing.
I tried 4, 9, 16 and 25 point leveling and all give disastrous results like you see in the picture in my first post.

You may have already tried this but I wanted to reach out just in case, there is a technique for leveling the Taz 5’s bed. Leveling the bed on a TAZ can be a little tricky until you get the hang of it. The most common issue new customers run into is making too large of adjustments to the corner pieces. In order to have a good starting point, please reset your bed. You are going to want to compress the corner springs to 3/4ths their maximum position. The easiest way to do this is to place your finger underneath the aluminum build plate, and tighten all for corners until the screws are sticking out to the same length. This gives a base starting point that allows for tightening and loosening on all 4 corners.

Once the bed is reset we need to set the initial Z height before making any corner adjustments. Measure the distance from the aluminum plate to the lower horizontal smooth rod of the X axis on both the right and left hand side. This should be equidistant. If an adjustment is required, turn off your printer and manually turn one of the threaded rods up or down to make the left and right hand side equal. Using a business card between the glass plate and the nozzle, home your printer. When it has finished moving, you should feel a slight tension on the card from the nozzle and the bed. If this pressure is not present, or is more than slight you will need to adjust your Z axis thumb screw and re-home. Once this is set in the home position, we can test the other three corners.

Turn off your printer or disable your stepper motors to allow manual movement of the bed and tool head. Move the tool head and the bed to test all 4 corners approximately 1 inch in from the sides. You should feel the same slight tension on the card on all four spots. If needed, adjust the bed corners to achieve this. The bed corners work much in the same way as replacing a car tire. You will want to make small adjustments as changing one corner will affect the other three. The business card it just a quick set in order to get your bed calibration print to stick. Fine adjustments will be made after the bed calibration print to achieve the proper height as highlighted in step 5 of your quick start guide.

Here is a helpful link to the online instructions on bed leveling: https://www.lulzbot.com/support/taz-bed-leveling

Here is another helpful link to that same procedure but in video form: https://www.youtube.com/watch?v=EdB8jbXFfns

Thanks Galadriel for trying to help; however I put the TAZ 6 bed with the ninjaflex and corner washers on my printers’ bed because the TAZ 5 bed would never get level.

One of the problems with the TAZ 5 corner clips is that they constrained the bed and introduced a bow in the center of the glass whenever the 4 corners would be level.

Back to the drawing board…