Cells, conveyors and presses — where most LOTO citations come from.
General manufacturing is where OSHA writes most of its lockout citations, and the reason is not exotic equipment. It is volume: dozens of machines, hundreds of isolation points, a maintenance crew that rotates, and procedures written for one line that get reused on the next one.
A robot weld cell is the compact version of the whole problem. Electrical to the controller and the welder, pneumatic to the clamps, water to the torch cooler, gas to the shield — and a safety circuit that must stay live so the light curtain still works while the cell is open. The procedure has to say which is which.
The most common finding is not a missing lock. It is a procedure that exists on paper for a machine that has changed, inspected by nobody since it was written.
A template written for line 3 is applied to line 5, which has an extra pneumatic feed nobody wrote down. The lock goes on; the clamp cycles.
Shift change mid-job. The lock is there, the person is not, and the record says only that a lock was applied — not by whom, or who took over.
(c)(6) requires each procedure to be inspected at least annually by someone other than its user. Most plants cannot produce the list of which were, which were not, and who did it.
Real isolation-point structure, illustrative tags, equipment that does not exist. Free to read and download. An example to learn from — not a document to adopt.
Full energy isolation of RC-14 for weld gun tip change and reamer service. Entry into the cell.
- 11 isolation points
- 1 must stay energised
Die change on a 450-ton hydraulic press. Covers accumulator stored energy, slide gravity restraint, and nitrogen gas-spring die cushions that have no lockable isolation device.
- 12 isolation points
- 1 must stay energised
- 1 cannot be isolated — managed by other means
- 3 with a stored-energy dwell
Capper head rebuild plus filler bowl internal inspection. Includes DP-1 depalletizer isolation and CO2 purge.
- 13 isolation points
- 1 must stay energised
Anode replacement and tank entry on an electrocoat dip line. Covers the DC rectifier bus, the overhead conveyor carrying bodies over the tank, circulation and heat exchange, and the ventilation that must stay live in a solvent atmosphere.
- 12 isolation points
- 3 must stay energised
- 2 with a stored-energy dwell
Maintenance at a module stacking and busbar welding station on an EV battery pack line. Covers the packs themselves, which arrive charged and cannot be de-energised, alongside the laser welder, station power and the gas detection that stays live.
- 12 isolation points
- 3 must stay energised
- 1 cannot be isolated — managed by other means
- 3 with a stored-energy dwell
Turret tooling change on a high-containment rotary tablet press handling a potent compound. Covers compression pre-load, turret rotation, wash-in-place lines, and the pressure cascade that must hold throughout because it is the containment.
- 12 isolation points
- 3 must stay energised
- 3 with a stored-energy dwell
Every point carries what to do with it — isolate and lock, apply and verify, or keep energised — so the safety circuit that must stay live is recorded as such, not left to memory.
Due dates per procedure, tied to the version reviewed, with an independence check on who reviewed it. The (c)(6) attestation is a report, not a hunt.
Handover is a two-party act — proposed, accepted, credential-attested — so "who was responsible at 03:10" is answerable from the record.
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