Ask the Stamping Expert: Do die repairs require full lockout/tagout?

Q: Are we required to perform full lockout/tagout (LOTO) on a press when we need to repair only the dies? The electrical components of our continuously running presses are failing prematurely because we power down the presses so often to perform full LOTO.

Can we just use the die safety blocks? Do the safety blocks and electrical interlock alone provide adequate protection every time that we need to put our hands in the die area?

How does OSHA’s minor servicing exception fit into our stamping plant?

A: OSHA’s minor serving exception—and, in your case, failure of press controls through constant shutdown—cannot be used as an excuse not to comply with OSHA’s 1910.147 LOTO standards. Anytime you need to put your hands in the die area of a press or you need to work on the die, you must follow the OSHA regulations. There are no exceptions.

In the photo of your pneumatic die safety block (see Figure 1), the safety block chain is connected only to the air supply. That is unacceptable because the main motor and flywheel still can be running. You must have an electrical interlock to stop all motors that can cause movement of both the press and feed.

The objective is to break the electrical circuit to the main motor and feed drive so it cannot run when the safety blocks are put in the die area. This can be accomplished by connecting a dummy plug to each safety block with a metal chain. Removing the plug from the socket breaks (opens) the circuit.

You can keep the panel view live with a circuit revision. This will help you with control component failure.

Although the plug is removed, the flywheel might coast for a short time. You’ll need to check the main motor and flywheel to ensure they’ve stopped. If the flywheel continues to turn, it will generate enough energy to crush the safety block if the press engages.

The lockout procedure is not required by OSHA for minor adjustments or service activities if they are part of normal production or if the unexpected energization or start-up of the equipment would not affect the employee’s safety and appropriate protection of the employees is provided. At no time should the employee make any adjustments or service within the point of operation (die space area) or other hazardous area without taking proper protection measures that meet OSHA and ANSI requirements.

The minor servicing exception for normal and repetitive tasks requires that safety procedures be documented for each process. It must be authorized by your company and safety department, with training given before the implementation of the process. The written procedures must meet OSHA’s 1910.147 regulations and be proven effective protection for all employees.

Regardless of how troublesome these procedures might be, you and your company are responsible—and liable—for protecting the people in your press shop.

Figure 1
In this pneumatic die safety block, the safety block chain is connected only to the air supply, the main motor and flywheel still can be running.