November/December 2020

DOLD Industries Ltd Telephone 01245 324432 • Fax 01245 325570 admin@dold.co.uk • www.dold.co.uk Two wayWireless Safety the safe, reliable UH 6900 Customer benefits Long range ultra reliable radio transmission,(> 800 m) Maximum safety up to PL e,SIL 3 3 x Dual channel safety inputs 8 x Cross operated inputs & outputs Fast setup via free windows compatible USB software Extensive signal quality & operation diagnostics 800 m SIL 3 PL e Expand the possibilities of autonomous material transport +44 (0)1908 258258 oeeuk_sales@omron.com industrial.omron.eu/mobilerobots Contact us for proof- of-concept testing! Meet OMRON’s family of autonomous mobile robots. You don’t just get a robot - you get a total solution. Our family of mobile robots can safely and efficiently transport a wide range of payloads –from lightweight tasks of 60kg all the way up to 1500kg, even capable to replace forklifts. OMRON’s autonomous mobile robots (AMRs) are designed to dramatically increase productivity in manufacturing and logistics operations. 34 n SAFETY November/December 2020 www.drivesncontrols.com active hazards or operations that could cause a hazard, operators can enable a“dead man’s switch”, which turns off automatically if the user stops exerting pressure on it. For maximum safety in collaborative operations, manufacturers must validate the safety of their cobot applications across all operations. Some dangers, such as drive and power hazards, might still exist even if the robot isn’t moving. Operator safety Before starting a cobot or recovering from an emergency stop, an intentional act is needed to enable the robot. For example, if an operator activates an e-stop, the robot should not be able to re-enable automatically, but should first be verified by a second operator. During the design and safety set-up phases, hand guiding must be allowed only if the robot has stopped, there has been intentional mode selection, and speed and force monitoring are active. If hand guiding is activated without a stop command or safety input, this should initiate a safety stop and fault. To operate a cobot automatically, the operator must make an intentional mode selection that requires all safety devices and conditions to be validated. For validation, a safety assessment review should be made of the surrounding areas and equipment and, if necessary, a safety remediation service performed. Safety service groups should make on-site inspections of the safety of equipment, confirm certifications, verify safety parameter settings and finally document the completion of the validation. Different types of application require different safety considerations. Machine tending applications are a top concern. For maximum safety, manufacturers should use safety-rated grippers to protect operators against injury. They should also investigate whether the products being handled present any dangers. Material-handling applications that can benefit from using cobots include picking, packing, palletising and sorting. The wide use of these applications makes safety site-specific. Operators and other workers oftenmove or transport materials around a cobot, so planning is needed to avoid hazardous contacts. Safety-rated grippers are rare. Manufacturers tend to use pneumatic grippers, with potential safety issues relating to impacts and the loss of power or suction. Designers must also investigate whether the product could pose a hazard if dropped. Assembly applications using cobots often require special tooling and close collaboration with operators, while also requiring high- speed operation zones. The wide variety of custom end-of-arm tooling makes these applications especially complex. For all three of these applications, it is important to review the entire area for the risk of operators becoming trapped or clamped by the robot or other equipment, and for the presence of heavy or hazardous products. Questions that apply to all three include: n should the safety controls of other machines be linked to prevent one from operating when another is in a safety stop condition? n because cobots can be moved from machine to machine and from application to application, how is their safety validated? n are there warning zones that indicate hazards or operation interference? Cobots are usually considered as safe for use with people. However, they still need risk assessments to ensure the safety of operators. It’s vital for manufacturers to consider all of the potential hazards associated with hand-guided teaching, as well as possible issues when a robot is involved in an emergency stop. Designers of automated machine tooling, material-handling and assembly applications should consider all of the interactions between the cobot and the human operator, along with the risks of clamping or entrapment, and the dangers from end-of- arm tooling as a result of high heat, sharp edges or other hazards. n