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The electronics production industry is characterized by a multitude of processes. From joining and separation technologies by means of laser, soldering and gluing, soldering processes, and the utilisation of fluxes or rapid prototyping—there is a wide range of various technologies.
All these procedures have one thing in common: they generate harmful particles of any size, form and composition. These particles have an undesirable effect as they have impact on humans, machines and products because of their chemical and physical characteristics. They can cause diseases, affect machine functionalities and pollute products, thus can be responsible for malfunctions and production failures.
Extracting is not Enough
Utilising an extraction system seems logical. Indeed, it is. However, systems vary in effectiveness and many critical parameters must be considered when selecting the most suitable extraction and filtration system. In order to completely removing all occurring dusts, fumes, odours, gases, and vapours, it is necessary to utilize the appropriate filtration technology and understand all the characteristics of the airborne pollutants and processes. A distinction is made between particulate and gaseous substances. Partially, gaseous substances may react and become particles. Modern procedures such as welding, laser or other thermal processes cause the emergence of particles, which become increasingly smaller and some are known to be in the nano range.
Particle size is one criterion that decides on the utilisation of the best suitable filter medium.
Additionally, knowledge on particle characteristics (adhesive, condensing, etc.), gas content or flammability is important. These factors also have influence on the selection of the ideal filter.
Air Filters and Subdivisions
Filtration means separation of solids and gases, and there are many techniques used:
• Gravity separators (settlement tanks)
• Centrifugal separators (cyclones)
• Wet separators (washers)
• Electric separators (electrostatic filters)
• Filtering separators (fabric filters, cartridge filters)
• Adsorptive filters (activated carbon)
This article focuses on filtering separators, also known as bag filters and fibre filters, as they are used across a wide range of industrial sectors. The German association Verband Deutscher Maschinen- und Anlagenbau (VDMA)/German Engineering Federation) subdivides filtering separators into different classes (Figure 1). Thus, a distinction is made between fine particulate (according to DIN EN 779:2012) and coarse particulate air filters (according to DIN EN 1822:2011).
Editor's Note: This article originally appeared in the March 2016 issue of SMT Magazine.