Linear Transport Systems Accelerate Machinery Advances
Mechatronic transport solutions provide benefits for packaging throughput and robotics integration while reducing machine footprint and changeover time.
Advances in all areas of automation technology continue to enable packaging operations to do more with less. New mechatronic solutions, which combine the principles of mechanical and electronic engineering for more flexible and adaptable machinery, take the next step. Linear transport systems in particular boost flexibility, throughput and the implementation of advanced production concepts like Industry 4.0. Packaging operations — from contract packagers with small lot sizes and large manufacturers that alternate between uniform, mass-produced products and custom products on the same lines — now require rapid changeovers with little to no downtime. Linear transport systems, including the eXtended Transport System (XTS) from Beckhoff Automation, provide this capability by combining the benefits of rotary and linear motion control into one solution.
These solutions use linear motor modules, which are fully integrated and provide both power electronics and position measurement, with highly customizable mechanical guide rails and movers. Programming via TwinCAT automation software replaces numerous functions previously completed with expensive mechanical components. Through these advantages, linear transport systems have enabled dynamic, intelligent product carriers and created significant benefits for real-world applications as diverse as bag filling, inline package assembly and product stream sortation and synchronization.
These features are important for packaging machines that require continuous flow, high precision and efficient self-reconfiguration based on anything from lot numbers to recipes. The advances of mechatronic technology make it possible to implement more machines in smaller spaces, achieve greater machine flexibility with very short or even automatic changeovers and dramatically increased packaging throughput. However, linear transport systems are not all created equally, so controls engineers and plant management must carefully consider which system to install on their machines.
Linear Transport System with Flexible Designs
Among the multiple options, engineers should select linear transport systems that can be installed horizontally, vertically or at angles, because the nearly unlimited configurations offer significant space savings. The mechanical components should be relatively flat, embed directly onto or into the machine and require no separate drive electronics or amplifiers in electrical cabinets. This can lead to 25-50% reductions in machine footprint from some systems. Beyond cutting control cabinet costs, linear transport systems also eliminate expensive components that were previously required for these applications, such as chain drives and actuators. Unlike these legacy components, modular track systems should allow for easy customization.
Some linear transport tracks combine to form complete loops — circles, ovals and S-curves — and simple straight segments depending on the application. Engineers should look for vendors that provide many options, ranging from guide rails that are not overkill for light payloads up to integrated heavy-duty solutions, such as HepcoMotion’s GFX Hepco Guidance System that can carry 12 kg loads. This flexibility is important for tracks of all sizes. While some linear transport systems are restricted to certain lengths, others have already demonstrated success in spanning 30 m or more as long as enough computing power is available to process the feedback. For power and communication, most linear transport systems use at least one cable per guide rail segment, and others need two cables per segment to daisy-chain the segments together. Only a select few have track segments that plug together as connected modules and require a single cable every 3 m to connect to a master controller.
Engineers should select linear transport systems with the ability to support unlimited movers. Some movers reach speeds of 4 m/s with acceleration up to 100 m/s², allowing them to transport workpieces at lower speeds and then rapidly return to the queue, ready to transport another. The motion software for designing the systems should treat each mover as a normal servo axis, enabling collision and jerk avoidance as well as automatic buffering. This setup provides linear systems with high accuracy and dynamics as well as other benefits of direct drive technology, such as resistance to wear, low vibration, and high energy efficiency. By choosing systems with optimal design features, packaging operations can achieve higher throughput and flexible changeovers.
Increased Throughput Even for Varying Products
Downtime is the primary enemy of any packaging line. However, many operations experience difficulties maintaining high throughput while managing changeovers to meet consumer demands for more custom and seasonal products. Mechanical components are typically the largest obstacles to rapid changeovers, but effective linear transport systems provide a solution through software.
When selecting a mechatronic system, engineers must pay close attention to the software capabilities, in addition to the physical components. Some automation software suites offer a standard framework with built-in diagnostics and useful functions, such as station-to-station and load applications, that make it easy to get started on a new system. Intuitive programming via IEC 61131-3 and computer science standards makes it possible to make changes on the fly in software rather than stopping production to adjust mechanical components.
Flexible linear transport systems enable implementation of IIoT and Industry 4.0 concepts in ways that are meaningful to packaging operations in the U.S. Domestic manufacturing of products down to lot size 1 is simple by loading predefined product parameters. Smart factories with cloud-connected packaging machines experience additional benefits because updates can be implemented remotely by machine builder OEMs or offsite engineering staff. With these capabilities, packaging materials and formats can change on the fly going into these systems and the movers can adjust positions independent of one another, which is valuable for asynchronous processing and limiting changeovers.
Expanding into New Motion Control Concepts
Linear transport systems possess impressive capabilities on their own, but by combining multiple tracks or technologies, they can revolutionize packaging machinery. For example, because the systems integrate readily into machines, multi-track motion architectures are possible. This enables movers from separate tracks — whether stacked on top of each other or collaborating with vertical and horizontal motion lines — to work together in real-time. The movers complete many tasks, such as carrying parts at the top and bottom or pinching toward each other to open bags at a filling station. However, these systems should also support dynamic expansion through track management and robotics integration.
Track management, specifically track changing, should be a top priority when selecting linear transport systems. This functionality enables the physical change of individual motor modules with their guide rails and the movers on them from one track system to another. Using a spindle axis or linear motor, the individual modules can integrate with other systems, and the motor modules and movers remain functional throughout the changes. Track management expands the system with enormous variety across machines — and eventually entire factories. This enables machines to sort out individual workpieces from the general production line, either for random sampling or to eliminate defective products or packaging.
By leveraging the real-time communication of EtherCAT, some systems can work in tandem with robotics. Linear transport systems offer the perfect complement to pick-and-place robots and other kinematics. Mechatronic systems that implement I/O and drive communication via EtherCAT, which is already a dominant networking standard for robotics, have the power to make generally asynchronous robotic handling synchronous, further improving throughput for packaging operations, speeding up changeovers and further reducing footprint.
As packaging automation continues to advance, packaging engineers and executives will need to implement new technologies to do more with less and keep pace with Industry 4.0 and IIoT concepts. Carefully designed and implemented linear transport systems offer a direction forward. By optimizing product flow, increasing motion precision and establishing efficient self-reconfiguration, these mechatronic solutions help packaging operations take the next step into world-class industrial automation performance.
Beckhoff Automation is a provider of advanced, open automation products for high performance machines. The company’s product range includes industrial PCs, distributed I/O, automation software, IoT solutions, servo drives, servomotors and linear motion solutions. For more information: beckhoff.com/xts/.
Matt Prellwitz, motion control product manager for Beckhoff Automation LLC, also contributed to this article.