Masters Abstracts (1994)

THOMAS, SUNIL
(October 1994), Manager- Application Engineering, Texas Instruments, Dallas, TX

Email: s-thomas12@ti.com

Measurement of Component Retention Properties of Solder Pastes for Printed Wiring Board Assembly

Recent studies that have addressed the tack related properties of the solder pastes show that the results obtained from the existing tack tests (mainly the IPC tack test) do not always correlate to the paste's behavior during the placement operation and during board handling movements. This necessitated a re-evaluation of the existing tack test methods and concurrently new methods had to be explored and developed. This research systematically evaluated the IPC tack test method. The study identified the factors that influenced the measurement and estimated their effect on the tack strength. It also developed an alternate tack test method by conducting statistically designed experiments using a shear tester. Tack life measurements were conducted for six different solder pastes using the IPC, the modified IPC, and the shear tack test methods. The test results were validated by subjecting the slugs placed on the solder paste specimen to a shock test and measuring the component movement. During the test validation process, it was confirmed that the IPC test results do not correlate to the component retention properties of solder pastes. However, the shear tack tests exhibited strong correlation.