Kinematic configuration — 6-DOF, SCARA, or Cartesian?
6-DOF anthropomorphic arms (the UR / Doosan style) cover the most application range — full 3D positioning with orientation control. SCARA (4-DOF, planar) is cheaper and faster for pick-and-place onto flat surfaces. Cartesian / gantry arms are stiffer and good for high-precision assembly but inflexible. We default to 6-DOF for general-purpose; SCARA when the application is clearly planar; Cartesian only for specific high-stiffness needs.
Joint design and gearbox selection
Each joint needs a motor + gearbox + encoder + bearing. For most custom Indian arms we specify cycloidal or harmonic drive gearboxes (now available from Sumitomo, Newall, and Chinese alternatives at reasonable cost), brushless servo motors with high-resolution encoders, and angular contact bearings. Joint torque budgeting matters — undersize and the arm sags under payload; oversize and you pay in cost and weight. Computed via worst-case payload at full reach plus dynamic loads.
Mechanical structure and stiffness
Aluminium structural members are the practical default — strength-to-weight ratio works for most payloads. Steel where stiffness matters specifically (typically the base segment). Hollow tubular members reduce weight at small stiffness cost. We use FEA (in-house) to verify stiffness under worst-case dynamic loads before fabrication — a stiffness study takes a few hours and prevents redesigns.
Software — MoveIt 2 + custom grasp planning
MoveIt 2 handles motion planning, collision checking, and basic grasp planning out of the box. For application-specific work — bin picking, machine tending, custom gripper coordination — we layer custom planners on top. Always build the simulation environment first (Gazebo or Isaac Sim) so software development and hardware development can run in parallel.
Manufacturing through Indian vendors
CNC machining for joint housings and structural members — multiple capable Indian vendors quoting competitively. Sheet metal for covers and shrouds — local Surat / Mumbai / Bangalore vendors. Custom PCB design and assembly — straightforward through Indian PCBA houses. Cycloidal / harmonic gearboxes — imported but landed cost manageable. Total bill of materials for a 6-DOF arm with 5 kg payload: typically ₹3-7 lakh, with software and engineering time on top.
Working with Yantrix on robotic arm design
We've delivered custom 6-DOF arms for teleoperation, pick-and-place, and machine-tending applications. Programs include mechanical design, gearbox / motor selection, embedded electronics, MoveIt configuration, and on-site commissioning. Send us your application and payload / reach requirements and we'll come back with a phased quote within a business day.