Bottom side adhesives

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I am evaluating a bottom side glueing process. I was wonde... - Oct 26, 1999 by K

When I evaluated a new glue type, I simply used a shear f... - Oct 27, 1999 by

#8813

Bottom side adhesives | 26 October, 1999

I am evaluating a bottom side glueing process.

I was wondering if anyone could share their shear force specifications, or how they were developed.

I would be most interested in the 0805 and Sot23 package types.

Also, does anyone know if heating these type of SMT adhesives to 230C rather than the typical 150C would adversely affect their adhesive strength.

Thanks;

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Brian W.

#8814

Re: Bottom side adhesives | 27 October, 1999

When I evaluated a new glue type, I simply used a shear force tester (Chatillon) to compare the cured strengths of the different glues. I sampled parts of different types; 0805, SOT23, 1206, and various tantalum caps. I analyzed the data based on each different type of component. Most (if not all) of the SMT adhesives do not like curing at 230. I used to have significant problems with missing components that we traced back to improper curing. Curing at too high a temp caused the glue to blow the parts off the board. Most of the adhesives cure in less than 2 minutes at 150 C.

Brian W.

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