| Electronics > Projects, Designs, and Technical Stuff |
| why did mfrs stop placing parts vertically on PCBs?? |
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| jaunty:
i'm curious as to why after the mid 1970s manufacturer's stopped doing things like mounting resistors and diodes perpendicular to the circuit board. Anyone know about this? seems after that point you'd ONLY see them mounted flat on their through-holes. Was there an issue with parasitic inductance? parts acting like little aerials and picking up strayEMF? Cost and labour (since they had to insulate the leads and it's likely a BIT more work to place the parts? or pick and place machines needing flat mount parts? inquiring minds want to know |
| coppice:
vertical mounting reduces the board area, allowing for a cheaper PCB, and makes the whole structure more 3D. This tends to suit packaging requirements better than having large low profile boards. However, vertical mounting makes things less robust. You need to ensure that knocked components don't short or break their leads. I guess you are seeing a crossover point where robust reliable results outweighed the benefits vertical mounting brings. |
| Conrad Hoffman:
We still mount vertically at times- when the SMT resistors and caps "tombstone" by accident! :-DD |
| Bud:
Most likely has to do with moving to automated assembly from manual one. |
| coppice:
--- Quote from: Bud on February 04, 2020, 03:00:25 am ---Most likely has to do with moving to automated assembly from manual one. --- End quote --- Board stuffing machines deal with horizontal and vertical mounting. I don't know if tthere are different defect rates for the two orientations, but they both generally work OK. |
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