The system comprises Glass Test Board (GTB) and AOI. The GBT consists of a glass with 400 pcs of 0805 chip models with spacing 300 µm and gap under chips 60+-5µm. Chips are sealed, which enables repeated underfilling of the board with flux from solder paste, passing reflow oven and cleaning. According to experience, first precondition for clean assembly is lack of any visible residues on the assembly. The GTB enables visually to check the residues under components. It is not built for demonstrating the maximal capability of cleaning under components but for process stability monitoring. For precise evaluation, the AOI tester can detect the almost clear flux residues under components of GTB and calculate a % rate of flux residues under each chip of GTB separately. One test gives 400 readings, which is enough to get statistically validated data on average cleaning results. The AOI generates a test protocol automatically within 3 min. The system can be used for flux vs. cleaner matching, machine capability study, process capability study and process change validation (IPC J-STD 001 Add. 01).
Productronica 2019: Halle A4, Stand 129