Issue link: https://iconnect007.uberflip.com/i/270052
86 SMT Magazine • March 2014 prints and paste F reached this criterion after 15 prints. Printing definition was better for paste F too: 16 prints against 14) prints. A detailed table for A, B, D and E is not reported. Pastes B, D and E were almost similar to F whereas A was below. The final ranking was, from the best to the worst: F, E, B, D, A and C. Examples of print- ing defects are illustrated in Table 7. The idle time was determinedand defined as the maximum time allowed for the paste to re- main on the stencil for a good restart without the need of under-stencil cleaning. The same cri- teria were used: Paste E showed the best idle time (3h,30) followed by F and D, then A and B, then C (1h,30). Results are summarized in Table 8. Paste aging under shearing was assessed: 600 printing cycles without paste consumption at 50 mm/s were made. All the pastes still looked smooth after the test, so the Brookfield viscosity at 20°C was measured. A decrease was observed due to the shearing for all the pastes, as seen in Table 9. feaTure rELIaBILITY aSSESSmENT OF NO-cLEaN aND WaTEr-SOLUBLE SOLDEr PaSTES, ParT 1 contin ues Table 6: Pastes c and f printing quality. Table 7: examples of printing defects. Table 8: Idle time.