Tolerance of SMT components placement/soldering

Thread Starter

g.b

Joined Dec 20, 2017
7
Not exactly a design question - more related to producton

What tolerance should I expect in placement of SMT components, that need to interface to a mechanical part?
Example - two pressure sensors on the same PCB with a cylindrical tube interface need to be inserted into matching holes in a manifold. While the holes position in the manifold can be done very accurately, I expect the placement on the PCB will have a larger tolerance which I have to take into account (if tolerance is too large then maybe it will not be possible to have them on the same PCB as it will create mechanical stress when inserted into the matching holes in the manifold).
So what tolerance should I expect (obviously not manual soldering)?
 

Irving

Joined Jan 30, 2016
3,190
When I last used Panasonic pressure sensors we made a decision to use the THT parts because, after experimentation, the only viable alternative with SMT was short flexible hoses that push-fit into connectors on the manifold. The THT parts were inserted later using a 3D-printed jig that located in holes in the PCB and positioned things close enough to be a push-fit into the manifold connectors after hand-soldering using the tall version of the sensor - though only 2 sensors. I'm not sure i'd do it for more than 2, or again like that, though AFAIK no failures were reported related to the mounting (however sensor reliability was a different story!)
 

Thread Starter

g.b

Joined Dec 20, 2017
7
Thanks. Maybe switching to TH would be a good solution, since drilling of the components holes and of the mounting holes is done on the same machine, so position tolerances may be tight enough.
 
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