Energy sources on a typical packaging machine
Every machine is different: check your model's nameplate, wiring and the manufacturer's manual. This is where most packaging machines get their energy and how it is usually isolated.
| Energy | Typical magnitude | Isolating device | How to control it |
|---|---|---|---|
| Electrical | 208–480 V 3-phase main supply; servo drives | Main disconnect on the machine control cabinet | Switch OFF and lock and tag the main disconnect. Wait the time stated on the drive for capacitors to discharge. |
| Pneumatic (compressed air) | Compressed air, typically 80–100 psi | Lockable air shut-off / dump valve | Close and lock the air valve and bleed the circuit until the gauge reads zero. |
| Thermal (heat) | Sealing jaws and heaters | None — cool down | Let the jaws cool before contact. |
| Stored mechanical (motion, springs, tension) | Film reel and dancer under tension; servo axes | Film brake / dancer lock | Release film tension or lock the dancer arm before working in the film path. |
| Gravity (raised or suspended parts) | Vertical jaws or raised parts (vertical form-fill-seal) | Mechanical block or pins (from the manufacturer) | Lower or block raised parts before reaching under them. |
Shutting it down
- Stop the machine with the normal STOP sequence at the operator panel (not the emergency stop, unless it is an emergency).
- Stop the infeed so no product or film keeps moving into the machine.
Releasing stored energy
- Bleed the pneumatic circuit and check the gauge reads zero.
- Release film tension or lock the dancer.
- Block vertical jaws or raised parts.
- Let sealing jaws cool.
Verifying isolation
- Press START at the operator panel and try to jog the machine: nothing must move.
- If the task involves electrical work, a qualified person tests for absence of voltage.
- Return all controls to OFF.
Things people miss
- Safety gates and their interlocks are not energy isolating devices and do not replace lockout.
- Lines with more than one machine usually need a procedure per machine and a group lockout for line-wide work.
Turn this into your written procedure
Add your company, the machine ID, the voltage and where each disconnect and valve is. You get a machine-specific procedure that follows the structure of 29 CFR 1910.147(c)(4), with an approval block and printable DANGER tags.
Start with the packaging machine templateQuestions
Does a packaging machine need its own lockout procedure?
OSHA 29 CFR 1910.147(c)(4) requires documented procedures for the control of hazardous energy. A procedure is not required only when all eight conditions of the exception in (c)(4)(i) are met, for example a single energy source that can be readily identified and isolated. Most machines with more than one energy source need a written, machine-specific procedure.
Is unplugging enough?
For cord-and-plug equipment, the lockout standard does not apply when the equipment is unplugged and the plug is under the exclusive control of the employee doing the work (1910.147(a)(2)(iii)(A)). If the plug can be out of sight or reach, use a plug lockout cover with a personal lock.
Is the interlocked guard enough?
No. Guard interlocks and emergency stops are not energy isolating devices and do not replace lockout during servicing, cleaning or clearing jams.
General information, not legal advice. Verify every energy source on the actual machine and have the procedure approved by a qualified person.