rUka 3R Robot Arm

myminifactory

Compared to my robot arm #BCN3DMoveo, rUka has a radical design with no axles, no bearings, no belts, no pulleys - each joint requires only one geared stepper, one printed arm and two bolts: M3 for the head and M5 for the tail. With fewer components comes less play and flex in the joints, shorter bills of material and assembly time. The arms of rUka are designed with strands running in the direction that gives maximum strength. Even a basic RepRap controller can operate rUka without expensive drivers for heavy steppers. Higher resolution is achieved through planetary gears. For example, slewing one degree at 16 microstepping and a gear ratio of 50.89 requires (16*50.89/1.8) 452.35 microsteps per degree. At an extension of 250 mm from the slewing axis, the effector should have a resolution of 0.01 mm (250*math.pi/452.35/180). Dividing MAX_STEP_FREQUENCY by 452.35 yields a rotation speed of 88.42 degrees per second. The linear speed of the effector at an extension of 250 mm is 385.8 mm/sec (250*math.pi*88.42/180). On those pictures, you see the R3 first version that will be used to develop the blender script for arm GCode generator. Later, it will upgrade to R4 where the hot end rotates to maintain vertical orientation and increase the effective build volume. So, an average of 300 mm/sec and a resolution of 0.01 mm are suitable values for normal FDM 3D printing. Hopefully one day, I will activate Moveo to retrieve finished parts printed by rUka. I'm switching to programming now. The album that needs updating is https://photos.app.goo.gl/Rk5VHIa0J8tnbySf1 and the ongoing programming and source files can be found at https://github.com/ShaukiBagdadi/rUka-Robot-Arm.