Improve quality with stencil design for inductor

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Hello all, I know there are very skilled guys. Can anyone s... - Oct 11, 2023 by Marks

Its highly doubtful that stencil design will fix this. The I... - Oct 11, 2023 by Sr. Tech

Agreed. Your "leads" are fairly small compared to ... - Oct 11, 2023 by ProcEng1

I don't think it's a stencil issue. You have an identical in... - Oct 11, 2023 by AlexV

Thanks for the opinions! You're right, it can't be solved wi... - Oct 11, 2023 by Marks

Marks

#90064

Improve quality with stencil design for inductor | 11 October, 2023

Hello all,

I know there are very skilled guys. Can anyone suggest a stencil design to avoid component displacement during reflow to improve tension of surface forces and selfalignment? There are cases where the inductors are shifted. All parameters are seen in attachment. Stencil thikness 0.100mm

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Sr. Tech

#90065

Improve quality with stencil design for inductor | 11 October, 2023

Its highly doubtful that stencil design will fix this. The Inductor floats during reflow and ends up going where it wants to go.

The only way you are going to keep it in place is to put a dot of chipbonder beneath it or change the size of the lands if possible.

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ProcEng1

#90066

Improve quality with stencil design for inductor | 11 October, 2023

Agreed. Your "leads" are fairly small compared to the PAD area, so you leave your part lots of room to "stretch it's legs". One thing that I have trouble communicating to my operators is that placement does not have to be perfect, and neither does the print. The paste will flow out evenly and surface tension will center the part pretty well. For your case, a dot of chipbonder, as suggested above, will be the easiest way. It will cure and hold the part before the solder really gets things floating.

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AlexV

#90067

Improve quality with stencil design for inductor | 11 October, 2023

I don't think it's a stencil issue. You have an identical inductor next to t=it, that's perfectly straight. You have a problem in that location. I've seen some inductors be affected by slight magnetic forces in the reflow oven. Try to rotate the board before the oven and see if that makes a difference.

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Marks

#90068

Improve quality with stencil design for inductor | 11 October, 2023

Thanks for the opinions! You're right, it can't be solved with a stencil. I have made investigation, the problems are related to the quality of the component land surface, one of the terminal is oxidized.

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