CLEANROOMS


Automating cleanrooms comes with a new set of challenges. How do these systems operate effectively without risk of contamination? Andy Pye looks at one approach


More skin in the game I


nmany industries, such asmedical and pharmaceutical research and production, contamination control and air purity are essential. Cleanrooms control the level of environmental pollutants present, such as dust,


airbornemicrobes, aerosol particles and chemical vapours, that can have a damaging impact on products and processes. At the same time, cleanrooms are embracing automation withmore andmore complex robotics and handling systems being installed. Automating cleanroomprocesses helps increase production, reduce cycle times and decreasemanufacturer’s costs. Contaminants can be generated by people,


processes, facilities and equipment. In automated handling equipment, such as pick & placemachines, the energy supply andmanagement systemcan be serious particulate generators and amajor design challenge. Up until recently, corrugated tubes have been used to fully enclose the energy supply system, which could include sensitive bus, data and fibre optic cables, as well as air and fluids. Cleanrooms are classified according to the


number and size of the particles permitted per volume of air. There are two accepted cleanroom specifications, ISO 14644-1 and Federal Standard 209E; however in Europe ISO 14644-1 is more commonly used. To give perspective, the everyday air we breathe contains about 35,000,000 particles per cubic metre, 0.5µm and larger in diameter, corresponding to an ISO 9 cleanroom, while an ISO 1 cleanroom allows no particles in that size range and only 12 particles


50 /// Environmental Engineering /// April 2017


 Suitable for ISO Class 1 applications, the e-skin’s oval shape offers more internal space than round cable coverings


Class


ISO 1 ISO 2 ISO 3 ISO 4 ISO 5 ISO 6 ISO 7 ISO 8 ISO 9


≥ 0.1 µm 10


100 1,000 10,000 100,000 1,000,000


per cubic metre of 0.3 µm and smaller. Igus specialises in energy supply systems for


cleanrooms and offers a broad range of approaches. A series of tests began in the Dryden Engineering Company (CA, USA) and were continued in the Igus test facility in Cologne, Germany and at the Fraunhoufer IPA institute with an extensive test and certification programme. One of themost recent developments is e-skin – a lightweight, versatile alternative to the corrugated tubes used in pick & placemachines, printers and othermachines The simple and reusable openingmechanism


allows for trouble-freemaintenance and inspection of the cables. The e-skin can also be tailored to an individual application and is available in a variety of materials and colours. Interior separationmodules provide cable-friendly guides. “Comprising an upper and lower shell, which


when fitted together is completely closed, the e-skin is simple to open and close,” says Igus director Justin Leonard. This easy-to-open hose is suitable for a variety of


delicate ISO Class 1 applications, where demands on the energy supply systems are not particularly high. It comprises an upper and lower shell, which when fitted together is a completely closed system. Unlike conventional corrugated tube, e-skin has a


definedmovement direction and can therefore be used as a horizontal energy supply for short unsupported lengths. In addition, thanks to its oval design, themodular tube offersmore space than round corrugated tubes. EE


ISO 14644-1 CLEANROOM STANDARDS Number of particles per cubicmetre bymicrometre size ≥ 0.2 µm 2


≥ 0.3 µm 24 237 2,370 23,700 237,000 10 102 1,020 10,200 102,000 ≥ 0.5 µm 4 35 352 3,520 35,200 352,000


3,520,000 35,200,000


8 83 832 8,320 83,200 832,000 8,320,000 29 293 2,930 29,300 293,000


Note: Uncertainties related to the measurement process require that concentration data with no more than three significant figures be used in determining the classification level


≥ 1.0 µm


≥ 5 µm


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