Virtually every designer of automation solutions for the food industry works with linear guides. They enable, for example, the movement of sealing stations in thermoforming packaging machines, the positioning of dosing heads in filling lines, and the guidance of cutting units in bread-slicing machines. Yet, as indispensable as linear guides are, they pose a challenge in hygiene-critical applications. This is because lubricants, abrasion particles and dirt can accumulate in gaps, on contact surfaces and in hard-to-reach areas. “When thorough cleaning is required, dismantling conventional systems is often time-consuming and limited by their design,” says Mira Loges, drylin development engineer at igus. There is therefore a need for linear guides that are designed to meet hygiene standards and can be cleaned quickly. “We have launched such a solution with the new drylin W series linear guide, which is the world’s first linear guide to receive certification from the European Hygienic Engineering and Design Group (EHEDG).” The EHEDG is an international organisation that develops standards for hygienic plant design to enhance food safety. An EHEDG certificate confirms that a component can be cleaned easily, thoroughly and safely – a key advantage for operators with the highest standards for process and product safety. The certificate provides recognised proof that the design of the drylin W linear guide helps to minimise the risks of contamination and failure.

Easy and quick disassembly for shorter downtime

Linear guides often make it difficult to clean machinery and equipment in the food industry. “Conventional recirculating ball guides, for example, often have to be dismantled using tools and removed via the end of the rail,” says Mira Loges. “This leads to unnecessary maintenance effort and downtime, which some users criticise.” The developers at igus have therefore designed the new linear guide so that it can be dismantled without tools. The system consists of two stainless steel shafts and a monolithic slide block made of high-performance plastic, to which users can screw their attachments. “If the system needs to be thoroughly cleaned, the carriage can simply be pulled off the rail and cleaned separately. The rail can be cleaned whilst still fitted, without the need for dismantling,” explains Mira Loges.

Lubrication-free hygienic design reduces the risk of contamination

Many conventional recirculating ball guides rely on lubricants to which dust, abrasives and dirt particles can adhere. This can result in the formation of an abrasive mixture that impairs smooth running and poses a potential risk of contamination. igus has therefore designed the new linear guide strictly in accordance with EHEDG guidelines. The electropolished round shafts have a surface roughness of less than 0.8 micrometres, which facilitates effective cleaning, as germs and product residues hardly adhere to the smooth surface. “During development, we consistently followed the EHEDG guidelines. One challenge was the transition from the shafts to the shaft supports or rail connectors. But here too, we managed to comply with the guidelines. The transitions have been milled so that minimum radii of three millimetres could be maintained throughout,” explains Mira Loges. A base seal made of FDA-certified silicone is also designed to ensure that neither dirt nor micro-organisms can accumulate between the rail and the surface.

Another special feature is the carriage made from the blue, high-performance plastic iglidur A160. It is PTFE-free and PFAS-tested, and integrated, microscopically small solid lubricants ensure a particularly hygienic, lubricant-free dry-running operation. “We have also ensured that the material has low water absorption. This means the carriage retains its shape and remains functional even after many intensive cleaning cycles.”

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