4 axis palletized robot arm (robot kinematics) for 3D printing

o_lampe

@droftarts I found a 4 axis palletizing robot from Sainsmart for 99$

With my CO2 lasercutter and some decent plywood or acrylic sheets, I think I could make a RRF version for steppers. (although those MG995 servos are hard to beat cost/power-wise)

@JoergS5 Your robot kinematics expect a step/dir interface, I guess?

droftarts

@o_lampe that looks interesting. From a quick look at the pictures, the extra linkages are doing the same (probably a better) job as the cables in my arm.

Ian

o_lampe

@droftarts As JoergS5 already said: the linkages make sure that the toolhead is always horizontal. Your arm has some deluxe options which are not palletizing-compatible.

droftarts

@o_lampe right I get it now. The tool head is kept horizontal (or vertical) and there’s no control over that. My arm has the extra controllable wrist joint, which makes it a five or six axis arm, I suppose. If I ignore that for now, I think I can still test the 4 axis palletised firmware.

Ian

JoergS5

@o_lampe said in 4 axis palletized robot arm (robot kinematics) for 3D printing:

robot kinematics expect a step/dir interface, I guess

the kinematics is integrated in RRF like the other kinematics. So the capabilites in respect to controlling interfaces are the same.

The Sainsmart has no parallelogram, but I analyzed it some time ago: the triangle on top has the same function, when thinking through the angles. Some of the commercial big robots use the same triangle construction (Kuka KR 700 eg).

Two parallelograms, conntected with a fixed triangle. Advantage: arms can be "bent down", disadvantage: more hinges, probably with play = less precision. For 3D printers, it may be better to construct it with a true parallelogram and the actuators higher placed.

JoergS5

If someone is interested to 3D print a 4 axis palletized, the MeArm 3.0 on Thingiverse https://www.thingiverse.com/thing:3420797 seems to be one. I'll take this for me to build one. I work this weekend on the firmware implementation.

A fork with steppers: https://www.thingiverse.com/thing:970881
There are other versions, searchable by MK2 design or Kuka 180 (= Kuka KR 180 PA).

o_lampe

@JoergS5 I found another one with NEMA17 motors, but it's quite outdated.
It uses spur gears instead of GT2 belts, which would be the minimum requirement for me to build one.

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YuriConfessor

Hello guys, I've been able to include the DH parameters directly to the gcode by creating a slicer using grasshopper. But this solution is not pratical in any form. @JoergS5 is it possible to launch a firmware with the DH enabled on the K13 so I can figure the robot directly on the config file? I'm using a cartesian kinematics and tricking the machine with the gcode. Here is a short video of it "building" a cillinder: lRobot kinda working

JoergS5

@YuriConfessor I will provide an unfinished version on Feb 24/25 for your printer type, which is missing some features like velocity/angle checks. I'll provide a Duet 2 binary for you.

YuriConfessor

@JoergS5 Ok, thank you! I'll post here if I have any updates