M2 Auto-Leveling Kit (Beta)

[PcS]

Actually in my testing the 4mm distance is really needed to avoid nozzle strikes. Unless you slow the whole auto level process way down. Or drop the probe a ton and account for it in z probe offset.
After g 28 or g 29 for that matter bed does not move up .so a second g28 keeps same offset distance.
did you set a z offset ? Or leave it at zero ?

[Tim]

did you set a z offset ? Or leave it at zero ?

Not sure if you're asking me, but I don't have anything attached to the printer yet. I will be getting a 4mm sensor in a week or two (missed the listing on Amazon, so I ordered on eBay to be shipped overseas).

Good point about the extra height needed to compensate for the movement during calibration. If the Zebra plate cuts that distance down by something between 1 and 2 mm, will there be enough room left to avoid crashing the z-probe into the bed? Or will I need to go look for a 5 or 8 mm proximity sensor (those are values of ones I've seen for sale).

Still not sure how to mount one of these things on the dual extruder. I think a redesign of the fan duct will be the best way, placing the sensor between and slightly forward of the two extruders. Probably want thermal shielding on it as well. I'm not sure how much heat it can take, but the tip of it is plastic.

[PcS]

4 mm will be enough. you may have to slow the whole process down a bit with the extra thickness. At least to avoid touching and errant readings. I would think even if mounted in between with sufficient airflow shielding wont be necessary. ???

[Tim]

I would think even if mounted in between with sufficient airflow shielding wont be necessary. ???

Well, true, if I mount it up against the fan, it will definitely be very well air-cooled.

[PcS]

lol ...Yup... I will say I am doing a larger print and I see the need to dial in the auto leveling a bit closer...but still not one failed print...and with petg....and I am still over extruding a bit...I would say it is a win.

[Bratag]

Just finished a print of a cell phone case for my nexus 5 - letting auto level take care of the Z. I have to say I am seriously impressed. My bed is all over the place out of level and yet the case came out perfectly. The only thing I had to tweak was the z-offset slightly.

Oh and on another note thanks to everyone who helped me get a handle on 3d modelling - because of you I was able to produce a perfectly fitting case, where every other one I had downloaded was off.

[Rara]

[wrong thread!]

[Josh]

Just checking in - I'm glad to hear you all are enjoying the autoleveling X)

As for the 8mm probe - in my testing, the 8mm probe I bought (with the orange tip and, IIRC, 24mm diameter) was too sensitive to heat: it would work initially, but then after printing for a while fail to detect the bed properly. It may have just been that individual probe, but the smaller size and higher reliability of the 4mm probe was why we went with that for now.

[PcS]

Thanks for the info Josh. And thank you for all the hard work !

[Tim]

As for the 8mm probe - in my testing, the 8mm probe I bought (with the orange tip and, IIRC, 24mm diameter) was too sensitive to heat: it would work initially, but then after printing for a while fail to detect the bed properly. It may have just been that individual probe, but the smaller size and higher reliability of the 4mm probe was why we went with that for now.

I noticed that due to the inductance needed vs. distance, the diameter of the winding (and therefore the diameter of the tube housing it) grows with distance. Given that I'm going to try to squeeze one of these between the extruder fan and the extruders, I want to keep it as small as possible. There's no room for a 24mm diameter tube. The 2mm distance sensors come in a really nice pencil-sized 8mm diameter tube. They would be perfect, if only they would actually detect the metal in the Zebra plate at 2mm. But the 4mm distance sensors with their 12mm diameter tube are a reasonable compromise. Apart from blocking the airflow from the fan, it should fit pretty well without my needing to move the fan outward by more than a couple of millimeters, if at all.

I haven't checked how the height correction is implemented in Marlin. Smoothieware has two separate routines: One is a three-point measurement that extrapolates a plane and corrects to that. The other is a whole grid of data points, which is the one I'm interested in. It will correct for any kind of nonlinear warping or bowing.