Yes, I was thinking it is a consideration, and worth checking up on. I'm not even 100% sure the product is going to have MEMs in it, but it's quite likely and I know ultrasonic welding is being considered. It might be as simple as providing some damping to the pcb. We do carry out significant vibration & drop testing, but this is a bit different. Obvoiusly, ultrasonic cleaning will apply vibration pretty well directly to the components, but welding could excite resonances not otherwise exposed. RP On 18 December 2014 at 21:53, RussellMc wrote: > > On 18 December 2014 at 21:32, Richard Prosser wrote= : > > > Does the same apply to assemblies ultrrasonically welded into a box I > > wonder? If so, this post could have saved us a bit of future strife - > > Thanks > > > > Yes and or no until > > you open the box (and may depend on whether you like or dislike cats) > . > Examining the box performance remotely is liable to affect the result. > > __________________ > > More seriously - I was only passing on Jesse's comments, but you can > imagine that the amount of ultrasonic energy reaching objects inside a bo= x > would vary immensely due to a wide range of parameters (overall dimension= s, > power level, resonances, mountings, substrate, box materials, box > dimensions and resonant modes and and and ...) and that there would be > cases where the answer was "often" and others where it was "essentially > never". > Knowing that the answer could sometimes be other than the latter is > valuable in its own right. > > eg if open ultrasonic cleaning essentially always destroyed a given MEMS > device it would almost certainly be possible to produce a housing such > that, by design, ultrasonic sealing of the housing almost always destroye= d > the MEMs device. If you can do it by design then Murphy can too. Equally, > it would be possible to produce a housing by design where destruction > almost never occurred. Murphy will work on "optimising" almost-never. > > > Russell > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .