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mrbi11 wrote: When I am talking about diagonal, I mean from top of print volume to calibration point, with mainly z axis travel.
Horizontal diagonal works fine.

I am saying if you go home, g28, then go diagonal to the calibration coordinates, you end up somewhere slightly different
than if you go home, then down, then to the same coordinates.

626Pilot wrote: The endstop screws handle the rotation of the plane of the build surface first and foremost. The rotations must all be correct for the bed to be level. Imagine drawing a "T" across the build platform. You start out at the X tower, then draw a line to the center of the platform, and that's the vertical line of the T. Then you draw a perpendicular line across the top of that one, forming the horizontal line of the T, stretching from one side of the build platform to the other. That line becomes the axis about which the platform is rotated when you turn the X endstop screw. The phenomenon to be aware of is that RAISING the platform near a tower LOWERS it at the opposite edge, and vice versa.

geneb wrote:FYI, the v.90 beta of Repetier firmware does make the radius value available in the EEPROM. I recall Flateric was playing with it.

uwes wrote: isn't the rotation axis (the bar on the T) defined by the direct connection between the other two towers?. as long as the end stop at a tower isn't changed the height shouldn't change.

do i miss something?

Maco wrote:Hi I found this anyone related?

https://groups.google.com/forum/#!topic ... rmxHMxdgBE

mhackney wrote:I've downloaded and gone through the calibration routines in the code he posted and it looks good and should do the job. We just need to port it to Repetier. It is also possible to use the math in his code, make the measurements manually with a dial indicator to populate the matrix, run the calculations and then set the parameters in Repetier.

Just out of curiosity, how important is a self-deploying probe to everyone here? Would a removable probe be acceptable? My preference is a removable to keep weight off the effector (I already have a Kraken so don't need to be slinging more mass!)

cheers,
Michael

Batteau62 wrote:The more I think about multiple head changes (pen holder, E3d, Stock, J-head, Kraken, indicator or Z-probe...) I'm liking the auto tool changer path in the future

bubbasnow wrote:there are a few videos floating around where people are using pressure resistors under the build plate, and the hot end just taps to get readings.. no probes required.

626Pilot wrote:

bubbasnow wrote:there are a few videos floating around where people are using pressure resistors under the build plate, and the hot end just taps to get readings.. no probes required.

I recently got email from the Deltaprintr guys that they are switching to that technology. Previously they were going to do a deployable probe calibration. I think the nature of their design makes tower angle errors unlikely, so hopefully their Marlin auto-level is good enough.

bubbasnow wrote:right i think the current limitation is that the resistors don't do well under a heated plate. im sure there is an easy fix for that

626Pilot wrote:I realigned everything but Marlin is back to doing that thing where it moves the axes in the wrong direction after running G29. I don't know what the deal is with that. Pretty irritating. Marlin overall seems more glitchy than Repetier.

Without autolevel, even after the realignment, it STILL acts weird around the X axis. I tried rotating the X and Y towers to 59 and 61 degrees but that didn't fix it. (I want to leave Z alone and use it as the reference tower, so it's level with the center, and then bring X and Y in line with it, because it's mathematically simpler.) Maybe I need to try something more aggressive.

At this point I find it unlikely that a Z-probe can take any of the work out of aligning a Rostock MAX by itself. I'm going to keep trying, but the results so far are not encouraging. Rotating tower positions is the only thing I find likely to work, and even that hasn't shown results yet. Maybe I'll stumble into some other solution.

I think the best autolevel system would be fully closed-loop during calibration. Three Hall effect sensors, one one each tower, a neodymium magnet on the effector, and a Z-probe as well. The firmware moves the effector to various positions and triangulates where it actually ends up using the Hall sensors, which would probably have to be plugged into the three unused thermistor inputs. (Hall-O boards have a raw signal line in addition to the "stop" line, which is strictly either high or low.) Since it can move the effector to a theoretical position and then measure the actual position with the Hall sensors, it can figure out the error between where it thinks it is and where it actually is at any point. With this we can derive the printer radius and delta arm length, and correct for any geometry errors. Additionally, the Z-probe lets it map the surface of the build platform, so it also knows exactly where it's laying down filament.