Laser cut 0.13mm stencil thicknes works great for us. BTW, are we talking RoHS solder paste? We do reduce the stencil apertures to 88 % of the pads when we go for the RoHS solder paste. Otherwise we go fo 96% reduction in general with some excemptions.
The reason for that is, the RoHS paste we use have a much better release from the stencil apertures. Except for the 0402:s and 0603:s where we use rounded corners on the stencil apertures, just for the paste release. On the very same boards we also have QFP: 0.5mm pitch and some heavy DC/DC converters (we overprint these bastards) along with BGA and front PTH connectors with paste in hole or P.I.P process. At the very same stencil! We have in a long term adjusted our stencil printing process/stencil design/reflow profife so it will work on almost every mixed scenario that we have to deal with and still to be able to fulfill the IPC/customer req.
Now, if You feel that the 0402:s gets to much solder and you don't want reduce the stencil thicknes, then I would recomend you to reduce the apertures to somewhat 75 -80 % and make them like this: if You know what I mean.
Haha, I tried to use some special characters on the keyboard to give You an idea what I mean, but hey, this lousy new regulation would not allow me to do so. It is hard to explain, but 0402:s works best with tis type of un-square aperture shape, where it should be; well I try again: No the SMTnet forum does not allow me to use special characters on the keyboard. Scheisse... I am trying to use the left and right "arrows" to illustrate what i mean. As a bonus, this will also help the small ones to center on their pads. Sorry for my poor english & grammar. /Sincerly Ps. This is my third and last try to post. Grrr. Grrr. Ds.
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