Through all of my experience with “auto level” and “auto bed mapping” (both on Marlin and Repeteir) I’ve basically found that it doesn’t work. Your 10x better off manually calibrating and forgetting about all “auto” levelers and bed mappings. Trust me…please haha.
Haydn’s provided copy of RC Marlin does a decent job at auto-calibrating, but still has crazy high homing speeds, accelerations and jerks that are too high imo for a accurate calibration. Slow it down and you’ll end up with a nicely calibrated printer. 1000 accel, 10 jerk, 40-60mm/s homing speed.
In the end it’s better off to do the calibration manually. You only need to tweak a few settings:
Horizontal Rod Offset: Affects printer “dishing”. Example of incorrect setting - hot end is lower/higher in center of bed than on edges. Example of correct setting - hot end moves in flat plane (even though plane may not be exactly parallel with bed).
Endstop Offsets: Lets you change the “level” of your printers plane. Can be done in software or with “trimming” screws if you have them. You have 3 towers to adjust (3 points make a plane) X, Y and Z. Z is typically your back post, Y is normally front right and X is normally front left. In your first picture, you have a X offset that is too big. You can thread in your X trimming screw to “offset” that part of the plane. Honestly, the hardest part of this calibration step is setting up predefined points to test at on an equilateral triangle. Also, don’t get confused between X,Y, Z your towers, and X,Y, Z Cartesian coordinates for testing.
Max Z Height: Raise or lower to compensate for for your endstop offset adjustments. For example, if you lowered your X offset to match your printers plane to your bed plane (leveling) you’ll end up with a gap too big across the surface. You’ll need to increase the Z Height to shrink the Z0 gap.
RC Marlin Calibration> Manually calibration > all autolevelrs
Personally, I use RC Marlin to initially calibrate (to get tower adjustments) and then just do my offsets and Horizontal Rod Offsets on my own.
A firmware that is not maintained since 2015 is not a option for me.
I am going to build a effector with zero probe-nozzle offset. Have you used one of these?
@Taylor_Landry I can, and I do. Shimmed at .05mm accuracy across my bed. Well built printer+ full understanding of delta calibration. I use FSR’s on my Kossel Clear and they work very well, but my Metal Delta is geometrically “square” enough to not need them.
Probing can work just fine. like I say I use it with RC Marlin on my Kossel Clear. However, for most users (especially novice firmware peeps) probing is tool that simply induces more confusion.
I’m sure your detailed explanation covers it all and works, but I’ve dug into firmware, and modified plenty of probing code, and every damn time it wasn’t worth it.
Edit: I won’t lie though, I don’t use Marlin much and I’ve heard it’s levling/mapping is pretty accurate.
@Taylor_Landry My zero-offset-effector is almost ready for printing. The proximity sensor will be mounted in the green part and points downwards to the hole in the pink part. It will be triggered by the head of a Screw in the pink part. The pink part will be hold down by a little spring that sits on the “trigger-screw” on the button of the effector frame. The tension will be adjusted by a secured nut. The yellow part is for the bowden-fitting.
First impressions. At a radius of something like 70mm it performs very accurate. Then the whole extruder starts to wiggle a bit when it takes the z-probe. This is caused by the force of the spring and the angles of the delta arms. The result is a slightly “higher” bed in the corners. Maybe i will try a weaker spring and try to tighten the nut before the actual print. Or maybe i have to tweak the DELTA_DIAGONAL_ROD setting in marlin. In operation there is now much less vibration on the effector btw.
The yellow part is for the bowden-fitting.
