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A practical breakdown of the main industrial robot types you will see on a manufacturing floor and the lockout tagout implications of each. Built for EHS managers and maintenance leads who need to write procedures around the cell they actually have.
The most common industrial robot. Six rotational joints arranged like a human arm. Used for welding, assembly, material handling, painting, and almost everything in between. Major manufacturers include Fanuc, ABB, KUKA, and Yaskawa Motoman.
LOTO implications: Multiple energy sources are typical. Electrical mains for the controller, pneumatic for end-of-arm tooling, sometimes hydraulic for high-payload positioners. Stored kinetic energy in counterbalanced axes is a frequent oversight. Gravity loads from elevated tooling and parts must be addressed in the procedure.
Selective Compliance Articulated Robot Arm. Four-axis robots optimized for high-speed pick-and-place and precision assembly. Common in electronics, small parts assembly, and packaging.
LOTO implications: Generally simpler energy isolation than 6-axis articulated. Electrical and pneumatic typical. Watch for stored pneumatic pressure at end-of-arm tooling and process media in feeder systems integrated with the cell.
Three or four parallel arms attached to a fixed overhead frame. Extremely fast pick-and-place, common in food and beverage and packaging. Often combined with vision systems for random presentation handling.
LOTO implications: Overhead mounting creates gravity hazards if power is removed without securing the end effector. Pneumatic vacuum systems hold parts even after main isolation. Cell typically has integrated conveyors and vision lighting that need their own isolation in the procedure.
Linear motion along three perpendicular axes. Cartesian robots are typically smaller and floor-mounted. Gantry robots are large, overhead-mounted, and span entire work envelopes. Common in heavy material handling, machine tending, and large-part assembly.
LOTO implications: Gantry systems carry significant gravity loads. Stored kinetic energy on long axes is substantial. Multi-zone safeguarding is typical and each zone may have its own access control placard requirement. Mechanical brakes and hold-position devices need explicit verification in the procedure.
Force-limited robots designed to work alongside humans without full perimeter safeguarding. Common in light assembly, machine tending, and inspection.
LOTO implications: The "no fence" assumption that drives cobot adoption does not change LOTO requirements during maintenance and tooling changes. Procedures still need to address energy isolation and verification. Pneumatic and process media isolation is often missed because the absence of a perimeter fence creates a false impression that the cell is "safe by design." It is not, during maintenance.
Articulated robots configured for arc welding, spot welding, or laser welding. Heavy use across automotive Tier 1 and capital equipment.
LOTO implications: Add high-voltage welding power, shielding gas, water cooling, and wire feed to the standard articulated profile. Stored electrical energy in welding capacitors must be discharged before service. Weld cell perimeters require dedicated access control placards because of the additional residual hazards (UV, hot surfaces, fume).
Articulated, gantry, or AGV-mounted robots used for palletizing, depalletizing, machine tending, and inter-cell transfer. Often integrated with conveyors and AS/RS systems.
LOTO implications: Multi-cell isolation is the dominant complication. A maintenance lockout on the robot must extend to the upstream and downstream conveyors and any integrated lift tables or transfer cars. Procedures that lock out the robot but leave conveyors live are a routine citation source.
Independent of robot type, the mounting configuration changes the LOTO picture.
Each robot type carries a different LOTO profile. A procedure that ignores the type-specific energy picture fails 1910.147(c)(4) regardless of how thorough it looks otherwise. A compliant program builds the procedure around the actual cell, including the robot type, the mounting, the end-of-arm tooling, and the integrated peripherals.
If your robotics LOTO program is using one template across all cell types, that is the gap to close first.
Free walkthrough. We map every cell on your floor to the right LOTO approach for its type and configuration. Written report within a week.