Material removal processes performed with collaborative robots typically include grinding, deburring, polishing, and light milling. These operations differ fundamentally from conventional machining carried out on CNC machining centers. Their primary purpose is not to shape a part from raw stock, but to refine surfaces, remove burrs, smooth transitions, or prepare components for subsequent operations. The forces involved are generally lower, and the tolerances are defined more by surface quality than by dimensional accuracy. This makes them suitable for automation in environments where variability of parts or short production runs would otherwise favor manual work. In this context, the cobot functions as a controlled, repeatable tool carrier rather than a high-rigidity cutting machine.
Stability, rigidity, and force control requirements
A key limitation of cobots in material removal lies in their mechanical structure. Compared to heavy industrial robots or machine tools, collaborative robots have lower mass and reduced structural rigidity. This directly affects how they respond to reaction forces generated during contact between tool and workpiece. As cutting or grinding forces increase, deflections and micro-movements can occur, influencing surface consistency. To compensate for this, force control becomes more important than absolute positional accuracy. Maintaining a stable and predictable contact force is essential to avoid chatter, uneven material removal, or premature tool wear. As a result, process stability is achieved primarily through control strategies rather than mechanical stiffness.
Tool guidance and the role of feedback
Precise guidance of the tool across the workpiece surface is critical, especially in applications such as edge deburring or weld seam finishing. In real production environments, parts rarely present identical geometry in every cycle. Small deviations caused by tolerances, fixturing, or thermal effects can significantly affect the outcome if the robot follows a rigid, preprogrammed path. This is why sensor-based feedback is increasingly central to cobot-based material removal. Force-torque sensors and compliant tooling allow the robot to adapt its motion dynamically. By responding to actual contact conditions, the system can maintain consistent process quality even when external variables change.
Power limitations and why cobots do not replace machining centers
Cobots are not designed to deliver the spindle power, cutting forces, or dynamic stiffness required for heavy-duty machining. Operations such as aggressive milling or removal of large material volumes quickly exceed their mechanical and thermal limits. Attempting to use a cobot in this way typically results in unstable processes, poor surface finish, and excessive wear on both robot and tool. For this reason, cobots should not be viewed as substitutes for CNC machining centers. Their value lies elsewhere, particularly in tasks that are labor-intensive, repetitive, or ergonomically challenging when performed manually. Within this scope, they complement rather than replace traditional machine tools.
Applications where cobots perform best
Cobots show their strongest advantages in finishing and preparatory operations that follow primary machining or forming steps. Typical examples include deburring of cast or machined parts, grinding of weld seams, and surface preparation prior to coating or assembly. In these scenarios, variable reaction forces are unavoidable, and the ability to adapt in real time becomes more important than raw power. Many integrators refer to such systems as material removal robots, a category well illustrated by application-oriented solutions described by OnRobot, where tooling, sensing, and control are designed as an integrated whole. These applications benefit from the cobot’s inherent flexibility and ease of deployment, particularly in small and medium-sized enterprises.
Process speed, surface quality, and safety considerations
Process speed has a direct influence on surface quality in cobot-based material removal. Higher speeds can improve throughput but also amplify vibrations and force fluctuations, especially near the limits of robot rigidity. Lower speeds improve control but may reduce economic viability. Finding the optimal balance is therefore a critical part of process design. Safety is another defining factor, particularly when material removal takes place close to human operators. The collaborative nature of cobots, combined with force limitation and continuous monitoring, enables safer interaction than traditional robotic cells. Nevertheless, tool selection, force thresholds, and risk assessment remain essential to ensure compliance with safety standards.
Technological boundaries and realistic expectations
The technological limits of cobots in material removal are defined by power, rigidity, and control bandwidth. Within these boundaries, they offer a practical and efficient solution for many finishing tasks that are difficult to automate with conventional machinery. Outside them, expectations must be adjusted to avoid misapplication. Understanding these constraints allows production managers and engineers to deploy cobots where they add real value, while relying on established machine tools for operations that demand higher mechanical performance.
