Issue link: https://iconnect007.uberflip.com/i/1415897
76 SMT007 MAGAZINE I OCTOBER 2021 e selection of a flux and cleaning pro- cess determines, to a large extent, the manu- facturing yield and product reliability of elec- tronic assemblies. In Part 1, I discussed vari- ous types of fluxes and why we use them, fol- lowed by various types of cleaning materials and processes. In this column, I will discuss cleanliness requirements to know wheth- er the boards have been cleaned enough to meet their functional requirements for their intended applications. I will discuss the cleanliness requirements in two parts. First, I will summarize the industry requirements as established in the latest indus- try standards, IPC 610 Rev H, and J-STD-001 Rev H, followed by my recommendations for cleanliness requirements without violating in- dustry standard requirements. Industry Cleanliness Requirements Among many other requirements such as set- ting up accept/reject criteria for solder joints, IPC 610 and J-STD-001 also establish cleanli- ness requirements for electronic assemblies. Here is what the latest revision (Rev H) of IPC 610 and J-STD-001 have to say about cleanli- ness requirements. Please note the use of the term shall instead of should in the standards to avoid confusion. General Industry Cleanliness Requirements As is the case for many other quality accep- tance requirements, IPC has essentially le it to the users and suppliers to determine the cleanliness requirements. I will highlight some Flux and Cleaning— How Clean Is Clean? Part 2 SMT Solver by Ray Prasad, RAY PRASAD CONSULTANCY GROUP