36 n LINEAR MOTION May 2024 www.drivesncontrols.com While electric actuators were formerly limited to strokes of 300 or 400mm, they can now achieve up to 1.2m. Compactness Actuators often need to t into con ned spaces. On packaging lines, for example, feeding and cutting systems may compete for space with other components. On AGVs or forklifts, space is always limited, and actuator sizes can also a ect energy usage. Actuators with housings a similar size to a passport can now handle loads up to 2kN and t into spaces for which earlier actuators would either be too large or too weak. Compactness and simplicity are major di erentiators from hydraulic and pneumatic systems, which need support infrastructure such as pumps, hoses, valves, reservoirs and compressors. Electric actuators simply plug into a power supply and connect to a network. Built-in PLCs can allow more ecient control, resulting in less downtime, higher productivity and cost savings. Intelligence Electric linear actuators are now available with modular onboard controls that enable simple on/o switching, low-level switching, position feedback and network integration. They can monitor and control, diagnose, read position and operating statistics in real time, and be ne-tuned on the y. As factories become digitised, designers will integrate material-handling capabilities into increasingly sophisticated operations. Loads will move more intelligently, allowing programmed motion sequences, remote operation, and synchronisation between multiple actuators. Long life Material-handling applications often run 24/7 in set-and-forget operation. Production line applications, such as arms that divert items from one conveyor belt to another, have high duty cycles and are subject to wear-and-tear. AGVs, forklifts and other mobile equipment may be deployed in those applications and usually run on batteries (Fig. 2). Equipment that is used outdoors or in hazardous environments, and is subject to ingress from moisture and dust, can also require long operating lives. Linear actuators using brushless motors can have 100% duty cycles and achieve up to 600km of maintenance-free life. This is a major advantage over hydraulic and pneumatic technologies, which require almost constant maintenance. In addition, lubrication technology has advanced to the point where some actuators are lubricated for life. And adherence to IP65, IP66 and IP69K standards can prevent particulate, moisture and other ingress that might otherwise shorten lives. Safety and ergonomics Material-handling equipment can pose risks to nearby humans. For example, a machine that loses power may drop its load faster than a human can get out of the way. There might be ergonomic challenges resulting from repeated movements or awkward workpiece positioning. For such situations, electric linear actuators provide electromechanical and static holding brakes that can hold the load in place if an application loses power. They can also make work safer by raising, lowering or tilting worktables to more ergonomic angles. Automated picking helps avoid long feeder routes and relieves operating personnel from machine work cycles as much as possible, keeping ergonomics and safety a priority (Fig. 3). Also, avoiding hydraulic cylinders removes the danger of product contamination, as well as the risk of slipping on leaking uids. Customising for competitive advantage While the range of available technologies is growing, application diversity is also driving the need for customised systems. Designers increasingly require components and systems to t unique needs. Often, manufacturers can meet these needs with minor modi cations to their standard o erings, but sometimes they have to design something from scratch. Some actuator suppliers can adapt their standard lines or have the expertise to design something completely new. New designs of electri ed actuators are often more modular than earlier generations, and changes can be made by modifying, adding or removing axes. This reduces the need to redesign large components such as a hydraulic manifolds, valves, tubes or hoses. What’s the return? To calculate the most accurate ROI on custom projects, designers must make procurement decisions that a ect the entire product lifecycle, including production costs, operating costs and productivity. The decision should factor in the bene ts of integrating technologies such as onboard electronics, which can contribute to greater competitiveness for OEMs and bene ts for end-users. Electric actuators are a key technology that connects the emerging digital world with the physical world. Until recently, this gap was too wide to span. But now that electric actuators are more powerful, smarter and more a ordable, the chasm is no longer so daunting. Electri cation is ushering in a new era of eciency, which will contribute to better automation, improved material-handling and, ultimately, better business. n Fig. 2 Electric actuators are now used on forklifts (left) and AGVs (right) to reduce the need for maintenance as well as to ease environmental concerns, and to facilitate remote operation. Fig. 3 Actuators can help to enhance the ergonomics of assembly stations and holding devices, making work easier, increasing operator comfort, and reducing the risk of injury.
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