Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Vias Under Discrete Components

Dreamsniper

#4657

Vias Under Discrete Components | 15 March, 2000

Do we really need not to locate vias underneath discrete components on a PCB that will be wave soldered after reflow even though we are using no clean process on our wave solder ? What are the possible cause and effect when locating Vias under discretes? All ideas are welcome... Ta. Armin

reply »

#4658

Re: Vias Under Discrete Components | 15 March, 2000

Armin: Locating vias within the courtyard of components is bad practice. Concerns are:

* Poor solder paste print quality, caused by the via preventing good stencil gasketing. * Poor component reflow, caused by the via holding the component out of the paste. * Shorting between the component and the via, caused by solder flowing up from the wave through the via. * Shorting between the component and the via, caused by solder flowing up from plating within the via. * Shorting between the component and the via, caused by the component metalization touching the via. * Shorting between the via and traces, caused by solder flowing up from the wave through the via. * Shorting between the via and traces, caused by solder flowing up from plating within the via. * Damaged component, caused by heat from the wave conducting through the via. * Poor solder connections, caused by heat from the wave conducting through the via and reflowing solder on the component.

Ta

Dave F

reply »

Dreamsniper

#4659

Re: Vias Under Discrete Components -Thanks DaveF | 15 March, 2000

DaveF, Thanks to all the support you were providing me. Appreciate all the help. Armin

reply »

SMT in-printer dispensing

reflow oven profiler