Vias Under Discrete Components

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Do we really need not to locate vias underneath discrete co... - Mar 15, 2000 by Dreamsniper

Armin: Locating vias within the courtyard of components is... - Mar 15, 2000 by davef

DaveF, Thanks to all the support you were providing me. App... - Mar 15, 2000 by Dreamsniper

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

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davef

#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.

Dave F

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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

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