Don, We investigated this same issue for Mil-Spec parts about two years ago. Because of our ultra-low volume, we tend to allow our parts to sit in stock for quite a long time prior to use. To summarize, we found that not all Mil-Spec, chip passives are tested for solderability on a lot to lot basis. Rather, a periodic sampling is performed on some types of chips (e.g., every six months). Secondly, we often times purchase parts from distributers who have had the parts in their stock for some time, with conditions which are pretty much unknown to us. We polled various manufacturers and were given times from six months to two years for shelf life of pre-tinned terminations. The actions that we took include assessing shelf life from the lot date code (date of manufacture) and not the purchase or receiving date. Establishing an eighteen month shelf life, prior to a lot sampling test for solderability (various locations on a reel proved to be impractical for us - right off the top). Initiating an end termination mechanical test. It turns out that end terminations are not tested for adhesion for the majority of passives we looked at. Lastly, it is considered the manufacturer's (internal or external) responsibility to assess the solderability prior to assembly - manufacturing risk. This implies that even if the parts are within the shelf life, we recommend that our internal labs sample the lots for solderability prior to assembly. Attrition quantities have been increased to allow for this type of sampling. Our ultra-low volume applications make it necessary/viable to perform some steps which production facilities may not have to/be able to perform. So please take this info with that in mind. Phillip Barela - Jet Propulsion Lab _______________________________________________________________________________ Subject: Shelf Life of Pre-Tinned Leadless Components From: <[log in to unmask]> at Internet Date: 5/9/95 7:23 AM Does anyone have any information regarding the shelf life of leadless pre-tinned components(chip caps and resistors, LCC packages)? First, what is the shelf life for these components when stored without significant precautions (ie. stored in orginal packaging, 20 to 50% R humidty and temperature 72 +/- 10 degrees).? What is the recommended storage to enhance shelf life? ie controlled temperature humidity etc. and do you have data on how long the shelf life can be increased. How does one go about testing shelf life for components packaged on a reel? By testing the first components on the reel does that give a good indication of the parts in the end of the reel? Thanks Dan Krebs AlliedSignal Aerospace