FlSun Kossel auto calibration. A concise guide?

I am fairly experienced at 3d printers, but new to deltas. I just completed a build of a FlSun Kossel XL and printed a calibration cube after basic manual build plate leveling.

While I have the plate fairly level, there is no way I can print a large item without a lot of time or getting auto leveling working.

I have read a LOT about it, but can not find a concise guide of exactly how to get this working.

Using the stock Marlin firmware that shipped with the printer, adjusted for correct height.

So far I have homed the machine and issued G29. This hits 9 calibration points on the bed, then goes to center and parks about 4 mm above the build plate. If I try to start printing at this point, it starts printing in mid air.

This is the type that the hot end is the probe and pushes up on a micro switch. What exactly do I have to do to translate my fairly level, perfect height in the center print to auto calibrate before prints? And not start printing 4 mm above the build plate? I did try issuing a g92 with what I thought the offset of 4.4mm was .. that didn't do anything.

Thanks for the help. Looking for a step by step to get this right and go about my business ....

- Jim

The easy way: [escher3d.com]
More details about how it works: [github.com]
If you do it right and your printer is otherwise solid you will be able to level the bed to precision of about ± 2 microsteps (or ± 25 µm if have 80 steps per mm). But precision of about ±50 µm is enough for good results. At the end, the final precision depends on how well your towers are perpendicular to your bed which is the think the above approach does not properly correct for. It's correction by chaning ednstop adjustement works only partially. Also make sure your arms have equal length (but that is easy to achieve if you built them in a jig).

Have a look at this topic:

[forums.reprap.org]

I looked at the topic referenced. It references Marlin-AC firmware; however, does not address my question on exactly how to use the M29 auto bed leveling and get that to actually translate into a print. As stated when I try the M29 I get 9 point leveling and the hot end centers and parks about 4mm above the service. When I start printing it just starts at that point in mid air.

The escher 3d method is not exactly what I was hoping for. I am just unsure how to use the auto leveling function and getting it to translate into proper starting height and starting the print. And what exactly do you do with the output of the escher calculator?

This is kind of frustrating as I have become pretty skilled at the Cartesian bots .. this is a whole new thing

SORRY! I actually opened the attached firmware and read through the doc ... I am going to work through it and see if it gets me where I need to be. This delta thing seems pretty far from "auto leveling" hahahah

Update. I loaded the Marlin-AC firmware and followed the enclosed PDF instructions. All went well. My last point of confusion is at the end of the document and it talks of Bed Leveling. The G29 code. It states it does not store in EEPROM. How do you use this in practice? Do I place a M320 then G29 Px Bx in the slicer starting code? Do I manually execute the M320 G29 prior to starting a series or prints as in it will stick till I reset the printer?

Thanks for the help. I am a lot further now.

You can do both; personally I do not use G29 any longer, a good calibration does the trick for me.

So the calibration procedure up to this point will store level bed data? If followed to this point the G29 should not be needed? Even if the bed is not completely level to begin with?

I have gone through the guide. Done all the procedures. Started with an almost perfectly level bed. Even did G29 procedure. I am obviously missing something. Prints in the center come out fantastic, but the nozzle is hitting the bed on the perimeter (see attached photo).

It is almost as if the bed is concave .. but I put glass on top of the aluminum plate to ensure a perfectly flat surface. What am I missing? Obviously people have got this right, there are just no clear step by step for us new to deltas.

Help!

I think the problem could be effector tilt caused by the rods pairs being not parallel enough. That was a problem on my FLSUN printer. The distance between the rod mount points on the effector is less than those on the carriages. To solve this I measured the difference with calipers and printed some shims of the correct thickness (different for each part of the effector) - see attached Openscad file. This improved but didn't entirely solve the problem. I'm using a RADDS board with Reprap Firmware so was able to use the H parameter to compensate for the remaining tilt. You could do something similar with the Escher3d wizard.

The thing that worked for me was adding springs between the rods; I cut the stock ones in half to get more tension.

[www.aliexpress.com]

Quote
jamesmoe
Do I place a M320 then G29 Px Bx in the slicer starting code? Do I manually execute the M320 G29 prior to starting a series or prints as in it will stick till I reset the printer?

Yep I stick the G29 in the slicer starting code.

I'm pretty sure it sticks until you home again (at least in Marlin it used to do this, in Repetier it sticks even after a home).

More instruction on how I did it are here:
[www.thingiverse.com]

Where are the endstop correction values in Marlin firmware? I am running through the escher3d.com calculator.

Flsun kossel delta with free auto leveling upgrade. Only available at [www.3dprintersonlinestore.com]