Tending CNCs Safely: Doors, Interlocks, and Guarding

Safety is the foundation of every successful cobot tending cell. CNCs include sharp tools, rotating chucks, and hydraulic clamps — hazards that must be isolated while maintaining productivity. The key: design for functional safety and human collaboration.

Core Safety Functions

• Door interlocks: Lock during machining, release only after motion stops.
• Safe speed (SLS): Limit robot motion when the door is open for setup.
• Safe stop (SS1/SSM): Controlled deceleration before door release.

Design Principles

• Keep robot reach outside the operator zone when possible.
• Use Category 3/PL d interlocks for dual-channel reliability.
• Verify the safety circuit with regular proof testing.

Example

A job shop integrated SLS and interlock feedback into its Fanuc cobot cell. Operators can safely teach new parts with the door open, while machining remains protected at full speed.

Related Articles

• High-Mix, Low-Volume Machine Tending with Cobots
• Quick-Change Grippers and Fixtures: Setup in Minutes
• Cycle Time Math: How to Hit Your Takt with Cobots

Conclusion

Functional safety makes cobots viable on CNCs. With proper guarding, interlocks, and control integration, productivity and protection go hand in hand.