11 months ago



Energy chains and cables

Energy chains and cables from igus are used in many Wemo products High-speed movements thanks to new reinforcement system AUTOMATION Pick & place applications, printers and handling systems have one thing in common: high cycle rates and very high dynamics. For the sake of economy, self-supporting corrugated tubes are often used for the energy supply. However, the fast movements often leading to damage of the corru-gated hose. A Swedish robot manufacturer has minimized the risk with a tube reinforcement from the motion plastics specialist igus. Mechanical engineering has a long tradition in Sweden. Business is good for the automation sec-tor, which is on the road to success. This enabled Wemo Automation AB to expand its business located in Värnamo, Sweden, and Reinheim in Germany, and had already announced its merger with Hahn Automation in May 2015. Wemo and Hahn are expanding and consolidating the robot business. While Hahn offers a product portfolio of larger robots with a focus on the automotive industry, Wemo’s core competence lies in the field of smaller to middle sized robots for the plastic industry. Among the highlights of the Wemo handling range are the “xDesign” series of linear robots. Ac-cording to the manufacturer specifications, they are the perfect all-rounders for the removal of various plastic parts and meet the highest demands for flexibility. The “sDesign” robots in turn serve for the removal of fast running packaging parts. These high-speed handling devices are opti-mised for maximum performance and speed. They ensure a cycle time of less than 2.7 seconds. How to prevent a breakdown of a robot At such high speeds, component parts are subject to high loads. In the case of cables and cable guides, Wemo relies on products from igus such as “e-rib”, the igus corrugated tube reinforcement for corrugated hoses from various manufacturers. In many of Wemo’s robots, the ready to connect igus chainflex cables designed specifically for moving applications are guided in

01 The Wemo portfolio comprises four type series – twelve robots, ranging from compact sprue pick-ers up to large robots with handling weights of up to 60 kg 02 In a retrofit, a supply part allows an upgrade of existing applications - the e-rib corrugated tube reinforcement can easily be retrofitted in existing systems “Flexible protection from igus prevents unwanted deflections in unsupported corrugated tube systems.” corrugated tubes for cost reasons, being lower priced than normal energy supply chains. The problem: In the case of quick lateral movements, unwanted lateral deflections of the vertically standing corrugation tube occur. In the worst case, this causes the hose to break. This can be caused either by over-expansion or by being caught in parts of the machine. As a result, the cables laid in the hose are often damaged, which leads to robot failure. “We had tried with an in-house development to prevent this oscillation. Metal at the bottom of the tube along with an inner fibreglass pin was designed to help. However, this was very complex and cost-intensive to implement”, says Olof Stahl, Director of Technical Management at Wemo. Finally, the first sample of the e-rib came to Wemo through the igus product manager, Ralf Kabus. The development then was carried forward in close collaboration, and a series product eventually emerged from the concept. The tube protection has already been significantly improved since 2015, says Ralf Kabus further: “Originally there existed only a nominal width of 29 mm and the protection could only be applied to PMA hoses. In the meantime, the e-rib can be used independently of the tube manufacturer. Three more sizes are now available.” Application advantages One of the positive features of the tube reinforcement from igus is its easy assembly: The e-rib is simply clipped onto the corrugated tube and can also be easily retrofitted to existing systems. The corrugated tube is then stabilised so that it can only move in one direction – lateral deflections are greatly minimized. The guide elements on the sides also provide for a larger unsupported length. The available sizes fit the tube nominal widths 23, 29, 36 and 48 mm. With the e-rib, igus had exactly the right solution ready to give precise support to Wemo. High-tech robots for the international market For Olof Stahl, especially the quick and easy assembly plays a decisive role in making competitive robots: “When it comes to money, we cannot be satisfied with low-cost suppliers from, for example, Asia. We at Wemo gain the edge with high quality and greater flex- ibility. Our international customers include many small companies that require high-tech robots for their production. Stand-ards – both in our handling systems as well as in the purchased parts – decide efficiency and prof-itability.” The period of four months from the date of ordering to delivery forty years ago, is cur-rently reduced to four to six weeks, according to Stahl. Monitoring system for cables and energy supply chains And in the future too, companies like Wemo can rely on the innovative support of igus. The ad-vances in the field of energy supply continue constantly, as Ralf Kabus explains: “For example, with ‘isense’, a monitoring system for cables, energy supply chains and linear guides, applications become safer and more economical. This is because these products report independently when a replacement is due, which leads to predictable reliability and maintenance.” The results from the 2,750-square-metre test laboratory in Cologne are incorporated here, where 1.4 million electrical measurements are carried out each year, which deliver reliable limit values for the service life of cables. “Our handling systems are often located in hot environments, such as injection molding machines,” explains Director Stahl of Wemo. “The plastic components used here must not soften. Since we started using chainflex cables and energy supply systems from igus, we have had no problems.” Photographs: lead / ornaments Wemo Automation AB, 01 + 02 igus Plastics for applications in motion The igus GmbH produces machine elements made of high-performance plastics, which are used in the field of movement and are characterised by a long service life and low maintenance (lubrication-free properties). The product portfolio includes over 100,000 solutions from stock, which are completed by systems and services. The innovative power of the company is reflected in hundreds of new products and solutions every year. The products are tested intensively to make specific predictions regarding service life in a variety of application scenarios. WORLD OF INDUSTRIES 1/2018 21


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