Hi Eric
That's more than a question!
1) the temp profile the part would see 5 mm above the PCB would be less than the leads would see, but exactly what the maximum would be really depends on what sort of wave solder machine is in use, and how it is set up.  For light boards it's possible to get away without topside preheat, but most use some amount of topside preheat.  I've got a convection preheater on the topside of mine, it would pump a fair bit of heat into a part such as yours.  Typically our topside preheater is run at 260 F, so a fair bit cooler than a reflow oven.  
As well, keep in mind that the package will contribute to how high a temperature the sensitive part sees.  
Can you make a mockup and try it?  

2) is wave soldering in common use?  Reports of it's demise are greatly exaggerated.  Very common - I don't know any assemblers who don't have at least one (although I'm sure someone is out there saying "wave?  you dinosaur!"...  )

3) will there be issues with lead free wave soldering?  I'm sure there will be.  Likely higher temperature requirements among them.

regards

Graham Collins
Process Engineer, 
Northrop Grumman
Atlantic Facility of Litton Systems Canada
(902) 873-2000 ext 6215

>>> [log in to unmask] 09/26/01 09:38AM >>>
I've got a question on wave soldering.

We have a temperature sensitive component that we need to connect to a PCB.
We know the component won't survive reflow temperatures but we could
redesign the package so that it is suitable for wave soldering. The
temperature sensitive part of the device is several mm above the PCB.

What sort of temperature profile could one expect say 5mm above the PCB?

Is wave soldering a technique which is still in common use or would finding
a wavesoldering subcontractor or equipment be like looking for someone to
service my Model 'T' Ford?

Are there (or will there be) any issues about wave soldering with lead free
solder?

Regards,




Eric Christison
Mechanical Engineer
STMicrolectronics
33 Pinkhill
Edinburgh
EH12 7BF UK

Tel 44 (0) 131 336 6165
Fax 44 (0) 131 336 6001

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