March 2019

| 48 | March 2019 www.smartmachinesandfactories.com | INTERVIEWS & REPORTS | and food industries, and in vacuum applications. Because the system is free from fiction, it should not generate particles or dust. Rexroth’s rival system is at an earlier stage of development than Beckhoff’s. At SPS, the technology did not yet have a name. Rexroth claims to have developed the system entirely in-house at its corporate research centre, where it has been working on the project for two years. The patented technology can currently carry loads of up to 1.5kg, which the company plans to increase to 3kg, with a target of eventually raising the payload capacity to around 20kg. The movers can travel at speeds of up to 4m/s, and the positioning accuracy is claimed to be 100µm during transport, and 2µm when stopped for processing. As well as magnets, Rexroth’s movers contain a battery-powered measurement system. They operate at a variable height of up to 20mm above the 240 x 240mm tiles, and can rotate “endlessly” through 360 degrees above any tile. Rexroth says that its system will not generate any heat, even when carrying maximum loads and operating with extended levitation times. Also, there are no significant electric or magnetic fields on the tops of the movers. The Rexroth system is still at the laboratory stage, but the company is hoping to start pilot installations later this year, before bringing the system to the market in about two years’ time. It expects typical uses to include micro-assembly, semiconductor production, packaging and cleanroom applications. Beckhoff believes that its levitating transport system with its “six degrees of freedom” will open up new avenues in machine design. It says that the movers will enable flexible, precise and highly dynamic positioning, and will simplify the design of machines and plants. Initially, Beckhoff is offering a starter kit in two versions to provide an introduction to the technology. The kits will contain all of the necessary components, including pre-assembled planar tiles installed in a frame. The electrical components and an industrial PC are installed in a control cabinet. The kits contain differing numbers and sizes of tiles. If Beckhoff and Rexroth are correct, then the factory of the future could look very different with scores of movers whizzing around silently and independently carrying their loads from one processing workstation to the next. of EtherCat that Beckhoff also launched at the show. The controller synchronises the motion of the movers and ensures that they do not collide. It also optimises their paths automatically and can control a group together to handle heavier loads. Beckhoff believes that the scalable XPlanar technology (which is based on a system called Xbot, originally developed by a Canadian firm called Planar Motor) will open up new avenues in machine design, offering machine-builders unprecedented levels of flexibility and simplicity. For example, in some applications the technology will be able to replace robots or inflexible mechanical devices. As well as being assembled in rectangular arrays, the XPlanar tiles can also be arranged as linear tracks. Extra tiles can be added to create waiting zones, or fast-track lanes than allow overtaking to avoid congestion. The movers can travel in any direction across a tile. Beckhoff envisages the system being used in automated packaging, assembly, sorting and order-picking processes. There is a choice of surfaces – easy-to-clean glass, hygienic stainless-steel, or plastic film – making it attractive for use in cleanrooms, in the pharmaceutical Rexroth was demonstrating a prototype of its levitating transport system at the SPS IPC Drives show in Germany