Automated Bed leveling --->Thats awesome!

[jamirie]

While looking for a good method to level my printers bed i found this:

hackaday.com/2012/04/23/automated-bed-leveling-with-our-3d-printer/

What the.... ??? This is definitely a feature every Printer should have, in my opinion. Why isn't this awesome feature more popular? Or did i just overslept it?

One of the last few lines in the report guesses that this feature (probes the surface of the bed) will currently (04.2012) be integrated in Marlin... That would be ingenius!

So i think about getting a metal plate instead of glass.... Anyone knows the pros and cons of a metal bed??? Would be very interesting!

[highcooley]

:-) A nice approach indeed

I cannot comment on metal beds, but I read this article back when it was released, and I was similarly baffled at first. However, on the second thought, it neither replaces a flat bed, nor does it replace a proper level one. But of course, this method can be of help for measuring everything. You could even think of rudimentary "scanning" objects to print later, in a method similar to a scanning electron micrograph.

Would it really help for uneven beds? I don't think so. Moving the Z axis along an uneven bed surface during print would maintain the correct distance to the nozzle. However, the print layers would also follow the same unevenness. In other words, you would have the same bumps throughout the whole structure of your print as you have in your bed. So, you still want a surface as flat as possible.

Would it help to compensate for a not correctly leveled bed? Only partly. If the Z axis would only follow the inclination of the bed, the whole print would be shifted in parallel. You could do the math and rotate the whole object to lay flat on the bed, ahead of slicing. The print would turn out in correct geometry, but this time, each layer of the print would be slightly shifted to the one before, leading straight vertical walls to turn out staggered.

Of course, I could be wrong, and the correction of a slightly uneven bed would improve print quality, leaving the staggering unnoticeable. For me, the effort for such small corrections seem to be quite big at the moment.

However, another interesting application of a Z min probe is to home the nozzle to the bed instead of Z max, simplifying correct Z height adjustment in the firmware. This has been done by several people in different ways (e.g. www.thingiverse.com/thing:7550). This method is pretty thrilling to me. But so far, I don't fully trust it, as the mechanics to move the probe out of the way during print, is not to be sneezed at (of course, you could use another set of sensors, to make sure, the probe is in full up or down position). I wouldn't want to see my nozzle crash into the glass bed at full speed, due to the probe not being in the right spot at the right time.

I hope, I didn't disenchant you with my view on this method. It surely would be very interesting to see, what other uses people could find for it.

By the way, in some G-code descriptions for marlin, you can find a set of codes for auto leveling. However, I didn't check if they are already/ still implemented, but it might be worth a try.

Happy printing
Andy

[jamirie]

Down to earth! After my post i went back to the site where it is posted and read all the comments.... So yeah, seems to be a nice tweak, but not that amazingly helpful i thought at first.

anyway---->happy printing