SMTA International Conference Proceedings

A Comparison of Localized Electronics Cleanliness Testing and Surface Insulation Resistance – Part 2

Author: Jason Fullerton
Company: Alpha Assembly Solutions
Date Published: 9/17/2017   Conference: SMTA International

Abstract: This study is an investigation and comparison of the performance of no-clean liquid wave soldering fluxes using a commercially available localized extraction and cleanliness testing system and surface insulation resistance (SIR) testing.

The flux test coupons for both tests were prepared in accordance with IPC TM-650 The IPC B-24 coupons used were manufactured using a lead-free wave solder process. Coupons were then tested for SIR per JSTD- 004B using IPC TM-650, and tested with localized cleanliness testing.

The results for fifteen no-clean fluxes are presented: three VOC-free rosin-free fluxes, two alcohol-based rosin-free fluxes, and ten alcohol-based fluxes with rosin. The results with six of these fluxes were demonstrated in Part I of this study.[1]

A divergence in test results is observed between the J-STD- 004B SIR pass/fail requirement of 100 MO minimum and the clean/dirty results provided by the cleanliness test system.

The SIR resistance/time graphs and cleanliness tester current/time graphs are compared. The Corrosivity Index (CI) calculated based on the result of localized cleanliness testing is compared with final SIR values for the fluxes.

Key Words: 

localized cleanliness testing, SIR, liquid flux

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