Preventive safety evaluations help protect personnel and equipment, cut costly downtime and losses, and minimize liability exposure. These are often known as Residual Risk Reduction or R3. This article highlights common areas of hazards in a manufacturing facility, and some potential solutions to explore.
Automated machines and robotic cells present a safety risk at the point operators must interact with the process, such as robotic welding or automated pallet shrink-wrapping. Safeguarding systems may include a combination of physical barriers, safety sensors, and advanced drives. Light curtains or other presence-sensing devices may be used to halt the process if interference is detected.
Some applications require more, such as a barrier to contain process-driven hazards such as fluid splatter/mist, weld smoke, sparks, intense flash, and light debris. A high-speed and automated machine safety door can meet these criteria and, help maintain a smaller footprint by eliminating the extra buffer needed for light curtains to create a safety zone. Manufacturers may offer a safety interlock option to meet PLe/Cat-4 safety requirements when combined with appropriate logic and conformance to risk assessment.
Beyond automated work cells, hazards also exist between operator and machining center. The manual opening and closing of a machine’s safety door can lead to repetitive shoulder injuries. Automating machine door operation can make machines more efficient and easier to use, but they pose a source of danger for personnel during loading/unloading.
Machine OEMs have employed automatic machine door actuators to reduce injuries from repetitive door operation and crushing incidents. Door actuators reverse automatically when objects are detected in their path and include the technology for implementing a safe force and speed limit for horizontal doors.
Large machine tools such as planer mills often are installed partially below floor level, resulting in potentially hazardous pits. Often, workers must remove pit grates or slats to service the machine. These are time-consuming to move, and slats require elaborate support structures that complicate maintenance tasks. An efficient alternative is a rugged pit safety cover that rolls-up and provides a continuous walk-on duty surface. Pit safety covers can be manually retracted or machine-driven.
Chemical tanks associated with metal finishing and other industries create open tank hazards, fume exposure, and are increasingly regulated for environmental emissions. Owners are pursuing cover systems which lessen the fume exposure and reduce the size and operating cost of ventilation systems. Covers can be made of steel or lighter materials such as polypropylene to withstand corrosive fumes. Roll-up cover manufacturers will work with the specific application to ensure a proper-fit/retrofit.
Hands & arm protection
Rotating parts or small automated compartment doors can cause injury. If contact is unavoidable, these incidents between human and machine must be gentle enough to not cause injury. A slip clutch or torque limiting device between the rotating part and the driveshaft allows the part to be stopped at a predefined torque without causing injury or damage to the driving motor. An application example is a disabled-access system that automates door opening and closing. The slip clutch permits door obstructions without causing injury or damaging the drive motor.
Scissor lift mechanisms, skillet lines, tilt tables, and similar equipment represent potential sources of injury because pinch points can be created when these mechanisms move. One way to protect against these hazards is to enclose moving parts with rigid skirting to deter personnel from reaching into hazardous areas. Bellows are a type of lift skirting that accommodate a wide range of motion and numerous platform sizes. Protective skirting can also improve machinery aesthetics and keep dirt and debris away from the lift mechanism.
Ball screws and other linear motion devices on industrial applications like lathes are often exposed. This can create a catch hazard for hand, hair, and loose clothing. Several solutions include roll-up barriers, telescopic covers, and telescopic springs which prevent accidental or opportunistic contact with moving parts. These solutions have the dual benefit of operator protection and protecting the linear motion guides.
Dust and sound
Large CNC machining centers require special effort to minimize the impact of dust and sound on surrounding work areas while still allowing access for loading and unloading large workpieces and tooling. In one application, a 5-axis machining center incorporates a retractable roof cover over its enclosure to answer both needs. Machine roof covers contain debris and airborne contamination without creating interference or obstructions in the machining center’s travel. Further, machine roof covers can be made from translucent material, which allows additional light to penetrate the enclosed area enhancing operator visibility to the process.