Auto-Calibration - $100 Bounty and Bragging Rights

[BONE]

New here, so I've only skimmed over this thread so far, but has this been discussed?

https://www.youtube.com/watch?v=HcnhCNh ... Wg&index=1

[JohnStack]

Of course there is this.

Not a new idea - measuring based on lasers and images captured from them; however here goes:

http://3dprint.com/9952/mit-researchers ... d-printer/

[626Pilot]

Hi, thread! How are you doing? Long time, no see.

I fixed the autocalibration problem with simulated annealing: https://github.com/626Pilot/Smoothieware

This doesn't meet the bounty conditions, but I'll tell you one thing: As far as I've been told, it works for everyone who has tried it. Positional accuracy is greatly improved, first by adjusting printer settings to correct for errors in X, Y, and Z; and then a final Z correction is added by depth-mapping the print surface in a grid.

You have to have a Smoothieware-compatible board (Azteeg X5 Mini or Smoothieboard 5X). So, it's not under $100. You also need a Z-probe, so it won't work if all you have is a dial gauge. (However, the Z correction can be hacked to work by manually editing the file where it stores the depths.)

It was always my hope that this would be ported to the Arduino controllers. I just posted to the deltabots group, asking Rich Cattell if he wants to port it to Marlin. Maybe someone can talk to whoever maintains Repetier.

[mhackney]

I'll grab that to try on my smoothie-equipped Mini Kossel. I'm waiting for the group buy details to pick up another couple of smoothies, 1 for the Rostock.

[gmh5760]

Pretty new to this stuff (only have a few prints under by belt), but what about monitoring the current to the stepper motors? The second they meet resistance (nozzle contacting the bed) the current to the steppers would rise. Would just have to program the variables such as current deflection requirements, distance ABOVE current deflection in which to call it "Z=0" (first layer base height), and then following calculation procedure (stepper motor current deflection point minus desired first layer base height, say 0.003", the steppers could then reverse travel to limits to "verify" Z. Could maybe utilize the same process (more trig) to calculate bed curvature).

[626Pilot]

Pretty new to this stuff (only have a few prints under by belt), but what about monitoring the current to the stepper motors? The second they meet resistance (nozzle contacting the bed) the current to the steppers would rise. Would just have to program the variables such as current deflection requirements, distance ABOVE current deflection in which to call it "Z=0" (first layer base height), and then following calculation procedure (stepper motor current deflection point minus desired first layer base height, say 0.003", the steppers could then reverse travel to limits to "verify" Z. Could maybe utilize the same process (more trig) to calculate bed curvature).

Some stepper drivers have missed-step detection. I don't know if any commonly available control boards actually plumb that into the controller's I/O lines.