Shopping for an industrial robotics cobot usually means choosing between two very different worlds: a bare-bones arm kit you build yourself, or a fully integrated collaborative robot that can sit on a production line. The ARM-21N4 5-DOF Robot Arm Kit ($119.23) and the Rethink Robotics Sawyer Collaborative Robot ($5,595.00) sit at opposite ends of that spectrum. Here's how to decide which one belongs on your bench.
Quick Verdict
If you need a complete robotic arm for machine tending, pick-and-place, or research with minimal setup, the Sawyer is worth the higher investment. If you're experimenting, learning, or building a small automated bench from scratch, the ARM-21N4 kit gets you moving without the financial commitment of a full cobot.
At a Glance
| Feature | ARM-21N4 5-DOF Robot Arm Kit | Rethink Robotics Sawyer |
|---|---|---|
| Price | USD 119.23 | USD 5,595.00 |
| Price indicator | ||
| Condition | New | Used |
| Axis/DOF | 5-DOF | 7-axis |
| Included | Unassembled kit with digital servos | Complete system with arm, controller, pedestal, cables, E-Stop |
Where Each Product Wins
- The ARM-21N4 wins on price, learning, and bench-scale tinkering. You get a five-degree-of-freedom arm, servo-driven joints with metal gears and double bearings, and a gripper holder that accepts suction cups, electromagnets, forks, claws, and grippers.
- The Sawyer wins on production readiness, payload, reach, and integration. Seven axes, force sensing in every joint, a built-in vision system, 4 kg payload, and 900 mm reach make it ready for CNC machine tending, inspection part placement, and packaging/assembly pick-and-place.
Product Notes
ARM-21N4 5-DOF Robot Arm Kit (Unassembled)
This kit is the entry point for anyone who wants to understand how an industrial arm moves without the cost of an integrated cobot. The 5-DOF layout, paired with metal-geared digital servos and double bearing joints, gives you a solid mechanical foundation. The gripper holder is a nice touch because it lets you swap between suction cups, electromagnets, forks, claws, and custom grippers as you experiment. The catch: this is an unassembled kit, so you have to put it together, connect the digital controller, and handle the control logic yourself. That makes it best suited for education, prototyping, and small automation experiments rather than production duty.
Rethink Robotics Sawyer Collaborative Robot
The Sawyer comes as a complete working system: robot arm, controller box, pedestal, cables, and E-stop. With seven axes, force sensing in every joint, and an embedded vision system, it's designed for the kind of jobs that require a full cobot setup. It carries a 4 kg payload and reaches 900 mm, so it can handle machine tending, loading inspection fixtures, and pick-and-place in packaging or assembly. The included Intera 5.3 software makes programming approachable, and the SDK mode with ROS opens up advanced research. This is a used unit with under 1,400 runtime hours, and it carries a much higher price tag than a kit, so you need to be ready for the investment and the infrastructure that a full cobot demands.
Final Choice by Use Case
If you're outfitting a lab or light production line and need a fully integrated arm with vision and force sensing, the Rethink Robotics Sawyer is the one to buy. If you're on a tight budget and want to learn robot kinematics, assembly, and servo control, the ARM-21N4 5-DOF Robot Arm Kit is your entry point.
