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SMT electronics assembly manufacturing forum.


Fillet height of SMT chip capacitor

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#81831

Fillet height of SMT chip capacitor | 29 January, 2019

Hi All, Can someone please help, I have a number of tall surface mount components that according to IPC 610 (8.2.2.3) are a fail due to the end termination not wetting at least 0.5mm + solder height. The components are very well soldered but the solder is only wetting 0.25mm up the component body. Is this normal and if not what could be some fixes? An example component would be a 1210 [3225 Metric] capacitor. Thanks for you help.

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#81836

Fillet height of SMT chip capacitor | 29 January, 2019

Your product is Class 3, correct?

Otherwise, a clearly wetted connection is all you need.

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#81840

Fillet height of SMT chip capacitor | 30 January, 2019

Hi Steve Thanks for coming back to me, you are correct IPC class 3 is required. We are getting great wetting onto the device but not as per IPC 3 with the wetting rising about 0.25mm. I am questioning whether it is actually possible with such a (relatively) big component without increasing the stencil thickness to the point where other components would have way too much solder. Any help would be greatly appreciated.

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#81842

Fillet height of SMT chip capacitor | 30 January, 2019

You could use a stepped stencil around the parts you're having issues with to add a greater paste deposit to them and not the rest, or slightly elongate the apertures and overprint, but this may lead to solder balling.

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#81845

Fillet height of SMT chip capacitor | 30 January, 2019

In addition to robl's suggestions, I would look at the footprint on the board to make sure it meets the recommended dimensions.

Abnormal layouts, particularly when pads extend under the component too far, can be problematic both by lifting the part and by thieving solder from the fillet.

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