Automatic Platform Leveling and Z Calibration made SUPER EASY

thingiverse

Well nearly automatic; it doesn't get much easier than this. This is for a Thing-O-Matic, but there's no reason you can't apply the same principle to any bot. This is simply a Z-Min endstop that works and is simple to build. Many thanks owed to DammitCoetzee, who thought up some even more clever directions to take this that I've not yet implemented. And many many thanks to Worksofman for the awesome aluminum plate. YOU HAVE TO SEE THIS VIDEO TO BELIEVE!http://www.youtube.com/watch?v=UdDoe01l6WU UPDATE! OMG! FORGET THAT VIDEO! WATCH THIS VIDEO INSTEAD! IT WILL EXPLODE YOUR HEAD! http://www.youtube.com/watch?v=XRt436ihaxw How many times have you had to recalibrate your Z? Not only do I never have to calibrate it again, I never have to go back and regenerate gcode if it changes. My gcode automatically takes into account the current Zmin/max. IS THIS AWESOME? SEE INSTRUCTIONS PART TWO BELOW. Here's a bonus, earlier video of me using the control pad to test it - trying to put it through the platform multiple times:http://www.youtube.com/watch?v=ZF10jI0xSao Some notes: Doesn't require any firmware mods or changes, unlike the ESTOP. If you are using the ABP belt, you can probably still use this outside its margins. I haven't printed on my fancy new alu plate, and I will cover it in kapton before I do. Of course I will cut small holes to use for this leveling technique -- and I also intend to test whether the system will punch through the kapton and trigger the stop, or not. -- UPDATE, it does not, unless the head is also moving in X+Y at the same time So don't count on this to SAVE YOU but DO use it to calibrate in test points you have removed the kapton! Video of punch fail here (not very interesting): http://www.youtube.com/watch?v=7x6tTmTuSH0 The SEXY and GORGEOUS alu plate was sent to me courtesy of Worksofman, whose website has some of the most fantastic metal sculpture I've ever seen: http://www.worksofman.com/sculpture ... but you may have to find your own source for the plate; I think it was a one-time deal. :) Instructions KNOWN REQUIREMENTS: 2 10,000 ohm resistors. 2 longish bits of wire (red and black would be nice) 2 female pin connectors of any type (my photos show I used a 4-socket female header to make it nice) some kind of wire insulator; kapton, electrical tape, heat shrink tubing... STUFF I'M USING I HAVEN'T TESTED WITHOUT BUT YOU MIGHT NOT /NEED/ AS SUCH: 6 short compression springs to fit the bolts on your build platform 4 long compression springs to fit in place of the spacers on your hot end. 1 TOTALLY SEXY alu plate with countersunk bolts. When this is activated, it seems instant and if the springs are adding any benefit, I'm unable to see it. But I don't intend the trouble of taking them off just to let ya'll know if it works OK without. My guess is it does. The same goes for the aluminum plate. The previous thing used the heat spreader and worked just as well contacting it. But I'm never taking this thing off; the countersunk bolts are awesome. HOW TO PUT IT TOGETHER: (See photos!) 1) Crimp/solder one end of the resistors each into a female pin. 2) Solder the other end of one to the black wire, and the other to the red wire. Insulate the connections. 3) Install them in a housing - or just plug them straight into the port. See photos. 4) Strip a small amount of insulation off the ends of the wires. 5) Red wire goes to the build platform heat spreader or SEXY ALU PLATE, and black wire to the head - wherever you like as long as it conducts! 6) If your platform is already covered in kapton, scrape off a tiny amount where you plan to perform the procedure, so it can easily contact the heat spreader or alu plate. 7) TEST IT... use a bit of wire to connect your platform to the nozzle and try to move it Z-; if it moves, check everything and try again. 8) Open the Thing-O-Matic Z Calibration Script as you normally would, but change this line: M01 (Turn the threaded rod... etc to this: G161 Z F500 (Boldly go where no one has gone before!) 9) Move your platform so the print head is aligned with your chosen test point, then... run it! Keep a finger on the power button just in case. Good luck! My personal recommendation would be to use the ESTOP and this both, and unplug the ESTOP while you are calibrating, so it does not shut things down. The problem with just using a Z-Min for /protection/ is it won't work well; the head will contact the plate and Z will stop, but X+Y will continue to move, which may (or may not?) scrape the plate. The ESTOP shuts down /all/ axis, hard. INSTRUCTIONS PART 2: Watch the head-exploding youtube video at the top, then contemplate this gcode while you put the bits and ends back together! : ( begin homing ) G162 Z F500 (home Z axis maximum) G161 X Y F2500 (home XY axes minimum) G92 X0 Y0 (set current position = 0) G1 X1 Y30 (goto 1,30 Z test point) G161 Z F500 (home z minimum) G92 Z0 ( Set Z axis minimum ) G92 X-50 Y-50 (set zero for X and Y) G1 X0 Y0 Z40.0 F3300.0 (move to waiting position) ( end homing )