Another try, hopefully this time with the text itself. We will be building a product for a customer that has three devices that need protecting from electrical access for security reasons. The customer wants a coating over the leads that will prevent people from probing them to find electronic access codes used in the system. Obviously this can only be a deterrent, as someone sufficiently determined could get past any coating or barrier. The coating needs to cover the leads only, so potting the entire assembly isn't on. It needs to be a fast in line process. I would like to limit any off line processing, like oven curing, to under one hour. The cured material needs to be resistant to soldering iron heat, the sort of solvents and acids that the PCB will withstand and the sort of mechanical attack that won't wreck the leads. After discussion with material suppliers I can see two ways of doing this. One is a filled rigid epoxy material of the type used for glob topping bare die, that will encapsulate the leads. This will be very resistant to attempts to remove it. The Cte will be closely matched to the package, lead and board materials, but the elastic modulus will be high. The other group of materials are of lower modulus. These however tend to be easier to remove. Processing will probably be dispensing from a barrel via an X,Y,Z dispensing system. Curing will either be heat, or UV. My principal concern is compromising the fatigue life of the solder joints by having a high modulus encapsulation material that constrains the movement of the gull wing leads and puts more stress on the solder joints during temperature changes. The product is a relatively high value consumer item for use in the home. Has anyone done something similar? What materials did you use? What were the results? What was the processing like? I will be doing some reliability tests, but the time constraints mean that the material choice needs to be right first time. One device is a 28mm body 0.5mm pitch PQFP. The other two devices are smaller in size. They will be conventionally attached to an FR4 board. Jeremy Drake. Design to Distribution Ltd. Kidsgrove, Stoke on Trent, England. +44 (0)1782 771000. [log in to unmask] *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************