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SAFE PRACTICE Optimal Machine Guarding



major cause of injuries in the metalcasting industry is machine caught-in/amputations. And

while a number of scenarios in metalcast- ing could conceivably contribute to this prevalent form of injury, machine guard- ing, or the lack of it, often is a major factor. Routinely lurking in the Occupa- tional Safety and Health Administration (OSHA)’s annual “top 10 cited” lists, it remains the elephant in the room that routinely goes unnoticed.

Guard Design Any guard that is designed in a way

that causes the operator to perceive it to be an obstruction to work processes or a hassle to reinstall once it’s been removed for servicing often ends up in a corner collecting dust. Tis circumstance, in turn, points to a component of effectual guard design that often is neglected: employee acceptance. It is imperative to evaluate machine guards for efficiency as well as effectiveness. At many metalcasting facilities,

machine guarding is addressed as an “after-market” concern, and often it be- comes the responsibility of the in-house maintenance staff to design, fabricate and install these guards. Management must take steps to ensure the final result enhances the safety of all potentially affected personnel, without becoming a detriment to production. Everyone accepts the fact that guards

must be securely fastened to defeat tam- pering, and most guard designs take that into consideration. Not all guard designers, however, take the ease of removing or reinstalling the guard into account. Addressing these issues by fabricating and designing the guard in a manner that makes it convenient to remove and reinstall is vital to achieve the ultimate goal of injury prevention.

Other Contributing Factors Routine tasks such as cleaning,

lubricating and adjusting are the most common reasons a guard is removed. Good guard design necessitates the utilization of

This locking interlock switch will only allow access to the af- fected equipment if the power source has been de-energized.

creative concepts such as remote lubri- cating devices or other provisions to make areas that require regular clean- ing more accessible. In the eyes of an employee, these solutions can be the difference between a practical, func- tioning piece of safety equipment and a contemptible hunk of metal.

What Needs Guarding

Operators and maintenance personnel need a basic working knowledge of the areas where guarding should be in place. OSHA’s “Machine Guarding E-Tool” defines “point-of-operation” as the point where work is performed on the mate- rial, such as cutting, shaping, boring or forming stock. Te power transmission apparatus includes all components of the mechanical system that transmit energy to the part of the machine performing the work. Tese are flywheels, pulleys, belts, connecting rods, couplings, cams, spindles, chains, cranks and gears. “Other moving parts” refers to all

parts of the machine that move while it is working. Tese can include recipro- cating, rotating, and transverse moving parts, as well as feed mechanisms and auxiliary parts of the machine.

Guarding Considerations Considerations for most effectively

guarding or shielding against hazards are: • Fixed guarding at point-of-operations. • Guarding by distance, i.e., railings, bar- riers, gates or photoelectric light curtain. • Two-handed control, to ensure body

parts are kept away from point-of- operation movements. And remember, a safe guard defeats its purpose if it creates a hazard of its own.

Action Plan During a non-production day, metal-

casting facilities should plan a complete walk-through and evaluation of their equipment to determine the guarding condition and effectiveness. A surprising number of guards may be found out of place, or needing repair or replacement. If the guarding doesn’t look just right, involve the operator or supervisor in de- veloping solutions to improve the design. It’s important to acknowledge employee acceptance as a key factor in guard design that will add an intangible benefit in reducing risk factors. Guards designed and fabricated in-house are particularly prone to design flaws on two ends of a spectrum. Tey are either designed with too much attention on convenience, or they are designed with a similar overzealousness to defeat tampering. Either of these can lead to a high risk of injury, which also results in reduced production. Machine guards can become dam-

aged or deteriorate with time. As part of a preventive maintenance program or during breakdown events, inspect equip- ment for missing or damaged guards. Until the proper guarding has been verified, ensure the energy is controlled by means of locking and tagging. Failing to control energy prior to removing a guard is a common occurrence, and workers often rely on prior “lucky experiences” to validate these unsafe actions. As any seasoned metalcaster can tell you, it is simply good fortune if no one is caught-in, or struck-by, the motion of compo- nents during maintenance or repair. It is easy to overlook something as ubiquitous as machine guards. Taking action to evaluate and correct guarding issues will pay dividends in providing adequate protection to the worker, minimizing risk of exposure to moving parts and complying with the standards set forth by OSHA.

February 2013 MODERN CASTING | 51

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