Technical Library | 2019-03-25 12:45:56.0
Work instructions are time consuming to generate for engineers, often requiring regeneration from scratch to address very minor changes. They need to be produced in varying levels of detail, with varying guidelines, for multiple stations, operators and lines. Minor component, station or process changes – down to the modification of an individual BOM component – can cause headaches when attempting to maintain consistency across multiple work instructions that are touched by the change.The solution presented here improves efficiency and saves engineering time by making use of a database driven approach. Manufacturing details, component information, process guidelines, annotations, machine-specific data, and more can be stored in one central database. Any information stored in this single repository can then be modified quickly in one location and automatically propagate seamlessly throughout multiple work instructions. These can be instantly printed out or displayed on screens at appropriately affected stations with the simple click of a button, as opposed to regenerating from scratch, or going in and reviewing many documents to find and update with the change.
Technical Library | 2022-10-31 17:30:40.0
This paper presents a quantitative analysis of solder joint reliability data for lead-free Sn-Ag-Cu (SAC) and mixed assembly (SnPb + SAC) circuit boards based on an extensive, but non-exhaustive, collection of thermal cycling test results. The assembled database covers life test results under multiple test conditions and for a variety of components: conventional SMT (LCCCs, resistors), Ball Grid Arrays, Chip Scale Packages (CSPs), wafer-level CSPs, and flip-chip assemblies with and without underfill. First-order life correlations are developed for SAC assemblies under thermal cycling conditions. The results of this analysis are put in perspective with the correlation of life test results for SnPb control assemblies. Fatigue life correlations show different slopes for SAC versus SnPb assemblies, suggesting opposite reliability trends under low or high stress conditions. The paper also presents an analysis of the effect of Pb contamination and board finish on lead-free solder joint reliability. Last, test data are presented to compare the life of mixed solder assemblies to that of standard SnPb assemblies for a wide variety of area-array components. The trend analysis compares the life of area-array assemblies with: 1) SAC balls and SAC or SnPb paste; 2) SnPb balls assembled with SAC or SnPb paste.
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