Auto bed leveling

Hi

Someone claims to have implemented an auto bed leveling technique in software with a mendel90:

[www.matterhackers.com]

I wondered how this is possible with two Z motors in serial connection and if there is some kind of exessive wear on the brass(?) nut on the threaded rods when the Z axis is moving constantly...

Anyone tried?

I would imagine if your bed is pretty level the difference would only be 1mm maximum, so probably hardly any wear at all.

I might implement it if I find my bed doesn't stay level....

Is it actually moving the z-axes independently or just performing a quick trigonometry calculation to work out where the nozzle should be to compensate for an unlevel bed?

the videos look like they move independently....

Which video? Or which part of which video? The only videos on that page I can see have them running in sync - the pointers move in opposite directions but they do that anyway. I haven't got sound on this machine so if there's narrative that goes along with this then please excuse me...

good question, I cannot find it anymore :/
I have seen to many bed leveling videos today, so it might have been as well another printer. sorry for the confusion

there is a topic in the german subforum that goes on and on about wear on the threaded Z rods and nut when auto leveling throughout the print....without coming to a conclusion

If it's any indication, I run 0.3mm lift on mine which makes an almost comical "whoop-whoop" sound after every layer. I know that won't be anywhere near the level of wear that constant bed-levelling would incur but if my rods wear out before the life of my printer I'll be sure to let you know...!

On a more technical note, I was under the impression that stainless steel and brass do not "gall", that is they do not cause wearing like steel-on-steel would, and this is the reason why brass is often described as self-lubricating. I haven't read the german sub-forum (my working knowledge of german wouldn't extend to any degree required to read about 3D printing and materials science anyway!) but apologies again if this has already been discussed at length...

Edited 1 time(s). Last edit at 11/05/2013 11:06AM by QuackingPlums.

the wear on the threaded rods is neglible even at worst!
Threaded rods cost like 3€ per meter, changing it out a 15min job - maybe needed after 100 000hours.

Just add a bit of MoS2 grease and they are going to outlast remainder of the printer by far.
Even if they would wear out, the cost of replacement is very tiny - so i don't see why people are worried over this?

If you are using lead screw, you are already using better than basic nut as well -> those won't wear. CNC, Milling and Lathe machines use lead screws and they don't in practice really wear out... Hell i know people are using some 50yr old lathes etc. There is many machining shops here in Finland with ridiculously low prices - because they paid off their machinery decades ago Those shops charge like 20€ for job another shop charges 200€ for

The matterhackers bed-levelling solution is based on an implementation by nophead (it is on his blog).

Basically, you probe a number of points around the bed and determine the slope error then during printing you adjust Z to compensate for the error. This is done by software that modifies the GCode so, technically, no hardware modifications are required.

Regards,
Neil Darlow

Edited 1 time(s). Last edit at 01/12/2014 05:54AM by neildarlow.

---

I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.