what is wrong with using the software endstops to auto-level the bed? June 15, 2015 01:24AM |
Registered: 9 years ago Posts: 280 |
Re: what is wrong with using the software endstops to auto-level the bed? June 15, 2015 05:45AM |
Registered: 10 years ago Posts: 14,672 |
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shadowphile
I have a standard ATMega 2560 with a RAMPS 1.4 board.
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shadowphile
...So all I really need is a routine that will automatically take out the doming and level the bed and set it exactly to zero.
I customized the G30 command in the firmware(RichCattel) by adding an 'ESj' parameter that must go with G30 Xn Ym command, ie G30 X-65 Y45 ES0 to indicate:
'probe at the X,Y location and use the measured z-height to adjust the software end-stops for the tower indicated by the value after the ES prefix.' (0=X, 1=Y, etc).
I have a Pronterface macro that calls this special G30 command at each of the towers in sequence, then the middle. If the towers zero-out but the center measurement won't, then I adjust the M666 R value until they
all converge to zero at the same time, while doing repeat runs of the macro. (I still have to save with M500 and manually re-home for now).
Just from the math, repeat runs should zero out all the towers (unless your chassis is too shaky).
Ideally the offset would go to zero in just one run. In my case after just two runs I had the towers AND the center within .01mm. This is amazing to me because I have been trying since last October to get my first printer actually printing and everything was a mess. I haven't yet confirmed the statistics of this result vs heating, moving, usage, etc, but at worst case I just run the macro again. It's very fast.
From now on, even if I move the rig or after I heat everything up, I just re-run the macro and end up with a nozzle that actually chatters as it moves sideways (chattering means it is half touching and half not touching, which is the ultimate best possible height due to nozzle shake from the steppers).
It would be easy to expand this to a larger automated process that auto-adjusts M666 X, Y, Z,R,H parameters.
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shadowphile
...Another thing I am pointing out is that IMHO printing the vertex part-sets may be considered cheap and DIY but for only $45 you can get all extruded anodized aluminum vertex parts (RobotDigg). That is even cheaper than printing and way more accurate and strong.
Re: what is wrong with using the software endstops to auto-level the bed? June 15, 2015 09:21PM |
Registered: 11 years ago Posts: 805 |
Re: what is wrong with using the software endstops to auto-level the bed? June 15, 2015 09:50PM |
Registered: 9 years ago Posts: 280 |
Re: what is wrong with using the software endstops to auto-level the bed? June 16, 2015 02:22AM |
Registered: 10 years ago Posts: 14,672 |
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shadowphile
What I need is a 'presence' based limit-switch method instead of a 'force' based method.