Hi every one..I want to convert kr6R900 into 3-d printer ..I am newbie .. NEED HELP PLEASE Suggest from where do i Start..??? how do i integrate extruder and robot motion...And main thing ..how do i convert .stl to KRL...?
Wanto convert kuka kr6R900 into 3-d printer..HELP!!!!!
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Fidanza3011 -
March 2, 2017 at 6:46 PM -
Thread is marked as Resolved.
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The honest truth? Lots and LOTS and LOTS of trial and error. There's no existing package off-the-shelf for this kind of thing.
First, in hardware: you'll need an extruder and hot end, and a means to control them from the robot. That will depend in large part on what I/O options your robot has. Controlling a stepper motor is fairly easy, as long as your outputs can keep up. That will require 4 DC outputs (probably 12V, possibly dry contact). The hot end will require an analog input for the temperature feedback, and a high-current output (probably dry contact again)to control the heater. You'll also need a good print bed -- it needs to be very flat, have good adhesion, and would work best heated.
Calibration: you'll need to create a Base reference frame matched to your print bed -- X and Y axes parallel to the bed edges, and Z axis orthogonal to the surface. You'll also need to calibrate your temperature feedback in the robot to convert the analog values the robot sees into accurate degrees C. Same for the heated bed, if you go that route. You'll also have to calibrate your extruder for steps/mm, and probably work out empirically what your upper speed limit is for "bit banging" the stepper.
Software: oh, now comes the fun part -- this could be months or more of work. First, since any STL slicer program outputs GCode, you'll need a way to translate GCode into KRL. There are CNC-software tools for doing this, but they're all for milling, not 3D printing, and tend to be Very Expensive. Long ago, I sketched out a python script for converting GCode to KRL, but it was extremely bare-bones and I never took it any further. You can find them at kuka.skyefire.org.
Converting the GCode motions to KRL commands is fairly easy, although getting those KRL motion commands to work properly is a very different story. Robots don't move like CNC machines or 3D printers, and have very different speed and accel/decel behaviors.
Which leads us to the biggest part of the problem: controlling the extruder. The extruder rate is set from the GCode, but also has to be handled on the fly by the robot controller. 3D printer firmware, like Marlin, already does this, but doing it on a robot is another proposition. The extruder rate would have to be linked to the difference between the robot's actual speed (in realtime) and the commanded speed. This would require some creative programming in the SPS, or some creative circuit-building (and firmware programming in an Arduino-equilvalent) making use of the KRL velocity-output feature.In closing, I have seen this done, and always wanted to try it myself (no one will give me a KUKAbot to play with, though. ). So it can be done. But unless someone has posted a project on Instructables or GitHub that I'm not aware of, you'll probably be doing a lot of heavy lifting on your own. It's going to be slow, and frustrating -- be prepared for that going in. And no articulated robot will ever be a match for a 3D printer in accuracy or precision -- too many kinematic differences. But it will be one heck of a learning experience.
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Hi SkyFire,
I am about to play around with an extruder on the end of a KR16. Any chance I could use your Gcode to KRL converter? I tried to get it from the link above but it won't allow me access..
Cheers
Martin -
Looks like the server didn't like Python files. I changed the extensions to .TXT and it should work now.
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Thanks, that works now.
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Try to use RoboDK simulation software, we're using it for 3d printing with our KR30 robot.