Linear Ball Bearing Stepper Slide

thingiverse

##28BYJ-48 Mechanical Actuator #4 I wanted to experiment with creating various mechanical actuators using the 28BYJ-48 stepper motor and primarily 3D printed parts. This motor, included in most Arduino kits, is a 5v dc motor capable of producing 15 rpm at maximum speed and delivering approximately 4 oz force/in of torque. These motors can be purchased with their drivers for around $2 each. ##Linear Ball Bearing Stepper Slide This design combines a linear bearing slide driven by a 28BYJ-48 stepper motor. The linear bearing utilizes standard .177 (4.5mm) caliber steel BB's, featuring adjustment screws to set the preload. The trapezoidal drive screw incorporates an integral ball bearing made from BB's to handle the thrust loads of the slide. I included two different lead screws: a twin lead screw with a 1/2" pitch and a quadruple lead screw with a 1" pitch. Given the maximum rpm of the stepper motor, which is 15 rpm, the twin lead screw will result in the carriage traveling at 7-1/2 in per/min, while the quadruple lead screw will travel at 15 in per/min. The linear bearing functions well, and the BB's recirculate as intended. However, there are some noise and vibration issues due to uncaged BB's meeting resistance during recirculation. In the next version, I plan to split the housing like a traditional linear bearing to see if this improves vibrations. This slide can move over 25 lbs with the twin lead screw, significantly increasing its load capacity compared to previous designs. If you have seen the Dovetail Stepper Slide, it could handle around 7lbs, making this version four times more capable due to reduced friction. However, the load stability is not as high as on the dovetail slide. The mounting holes on the base, carriage, and endplate align perfectly, allowing multiple slide assemblies to be bolted together for a two or three axis cartesian system. ==================================================================== ##Required Components - M3 Nut (14x) - M3 SHCS x 10mm long (12x) - M3 SHCS x 20mm long (2x) - .177 BB's (8x) for Thrust Bearing - .177 BB's (8x) for Linear Bearing - 28BYJ-48 Stepper Motor You can find a set of five stepper motors and drivers on Amazon through my affiliate link: https://amzn.to/2KJI6yz ##Assembly To assemble the linear bearing, start by installing two M3 x 20mm screws and nuts into the carriage for preload adjustment. Do not tighten these screws yet. Next, install the carriage on the rail and place it upside down. Fill each groove with 20 BB's and install the caps. Once the bearing is packed with BB's, adjust the screws to achieve the desired preload. Note: Using grease on the thrust bearing, drive screw, and nut will improve load capacity, lifecycle, and reduce noise and vibration. Avoid applying lube to the ball bearings, as it may cause issues with the balls recycling. If you're experiencing trouble with BB's recycling, try removing one BB from each side. You can watch assembly videos on YouTube: https://youtu.be/Yq39Y9Z1tzk and https://youtu.be/WCNtUWE9mQ0