electronics


environment and in leveraging the productivity gains available through automation. We are all aware of the widespread adoption


A


of automated soldering processes. They can make a significant positive impact on output and quality, but even so there remain challenges that need to be mitigated. For example, while automation reduces the need for manual contact, manufacturers do need to take account of any potential impact on workplace occupational health strategies. In the UK, employee health in the workplace


is mandated through COSHH (Control of Substances Hazardous to Health) regulations, which express workplace exposure limits (WELs) to defined substances and emissions. These WELs are presented as time weighted averages for either 15 minutes or eight hours in ppm (parts per million) or mg/m3 (milligrams per metre cubed). In the case of electronics processes, this might


include limits associated with emissions from rosin- based solder fume, solvents, fume associated with PCB marking and printing and adhesives. Aside from workplace environmental issues,


it is also critical that processes such as PCB manufacture remain free from dust to maintain quality. So effective filtration can be both a contributor to environmental management and to productivity. The checklist for operations and health and


safety managers includes understanding any potential risks to health resulting from any given process, assessing the installation and life cycle costs of either fixed or portable extraction systems, and anticipating the future mix of work relative to agility, capability and capacity. BOFA’s experience is that electronics


companies are increasingly opting for portable systems to support manufacturing flexibility. In specifying the configuration of an


extraction system, managers need to take account of the quantity and size of particulate emitted and its chemical composition, including the toxicity of each element of the process and any resultant chemical interaction. This will inform the design of the system


architecture, the filtration media used, the integration of sensors (for high temperature applications for example) and the most appropriate monitoring and control mechanisms. There are specific challenges presented


by automated processes in the electronics sector that need to be addressed. Take wave soldering for


example. Here, the ‘through-hole’ components are placed on the printed circuit board and passed over a continuous wave of molten solder. Areas not to be soldered are covered with a protective ‘mask’.


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ssessing the need for effective fume and dust extraction for electronics manufacturing is an imperative in both helping maintain a healthy working


Productive & safe working through effective fume


and dust extraction By Joshua Evans MEng (Hons) IChemE, applications engineer and head of BOFA Academy at BOFA International


While this process does not involve the


resin/colophony present in hand soldering (with its inherent health risks), it can require the use of an alcohol-based solvent such Iso Propyl Alcohol (IPA) and a small amount of organic acid, fume from which needs to be managed, extracted and filtered. Before soldering, the boards are ‘spray


fluxed’, using either a general spray process, which can generate an airborne dispersion of the flux, or a targeted jet from a robotic nozzle. Either way, the airborne contaminants created can be managed through effective filtration, which includes investment in fume extraction technology. With reflow soldering, solder paste is


applied to the PCB and components are then


‘picked and placed’. The board moves through various heating, stabilising and cooling zones, during which the solder metal ‘reflows’ or melts and solidifies around the component connection. During this process, the solvent which makes the paste liquify will evaporate and this airborne emission can then be filtered through an extraction unit. The fume from this process will include


rosin content, with the associated health risks. A solder flux may also be used, which is likely to possess a significant concentration of ammonium chloride. As with wave soldering, operating temperatures need to be taken into account to ensure the effective capture and filtration of any potentially harmful emissions. BOFA’s portable fume extraction solutions


help combat these risks, through multi-stage filtration technology that includes specialist activated carbon filters designed to capture specific chemical emissions. This contributes to compliant health


protection while helping deliver the productivity gains that come from mobile technology and fume and dust free process lines. Among the extraction systems specifically


designed for electronics processes is BOFA’s V 2000 iQ, a high airflow system for reflow ovens and wave solder machines, with large filter capacity.


BOFA International bofainternational.com


Summer 2022 UKManufacturing


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