Kosti-1 Robot Arm

thingiverse

Kosti-1 is a 5 DOF open-source 3D-printed/Aluminum robotic arm with a maximum payload of 500gm, a reach of approximately 55cm and a total part cost of around $700; the arm lies in the mid-range between small servo arms and multi thousand dollar projects and is generally aimed towards educational and hobby purposes. The manual, .stl files and files for CNC machining are included. # Things That Might Set This Arm Apart: 1- Rigidity: Most parts are 3D printed, but the shoulder and base are partially made out of CNC aluminium, which adds to the rigidity of the design. 2- Backlash: No gearbox needed for the base and shoulder joints, which means zero backlash at those joints. 3- Smoothness: Running the shoulder and base joints at quarter step settings, combined with the fact that the remaining joints have commercial gearboxes with large resolutions, can lead to very smooth movement. 4- Customizability: The design is entirely functional which makes it easy to modify; for instance, links can be lengthened or shortened without much issue, actuators can be replaced or modified, etc. # Reasons You Might Want To Look Elsewhere: 1- This arm isn’t entirely cost optimised; the commercial pulleys and gearboxes can be replaced with 3D printed ones or even be replaced with more affordable options, but further prototyping would be needed to achieve that. 2- This arm is not the best choice if you want something to reliably carry out practical tasks, and there are likely commercial options out there that better suited for this. 3- The arm uses open-loop stepper motors, and I haven’t added limit switches yet, meaning that the arm would need a pre known starting pose for every new run. 4- You can check this post for how I designed the arm: https://www.reddit.com/r/robotics/comments/15dx5fs/releasing_kosti1_how_to_design_your_own_robot_arm/ CAD files can be found here: https://www.cgtrader.com/3d-print-models/hobby-diy/robotics/kosti-1-robot-arm