FAQ: Where to get cheap stencils?

[JuKu]

I've got my stencils so far from http://www.eurocircuits.com/. Not the cheapest source, but has been convenient for me. Other links (disclaimer: I have no experience on these, just bookmarked):

http://www.smtstencil.co.uk/
https://www.oshstencils.com/index.php
https://www.pololu.com/product/446
http://ohararp.com/
http://www.stencilsunlimited.com/smt_stencils.php
http://www.protovoltaics.com/prototyping/

Also, this thread on EEVBlog: http://www.eevblog.com/forum/manufactur ... -stencils/

Here is a link to a video showing how easy it really is: http://www.beta-estore.com/rkuk/order_p ... .html?p=13

Feel free to add your links and experiences here!

[dmwahl]

Elecrow also will make stencils for an affordable price. If they're anything like their PCBs they should be pretty good quality. I ordered one a week ago, I'll update with results when it arrives.

[WayOutWest]

PCBWay now offers nickel-electroplated stencils.

If you've never used one, try it. They are massively easier to clean if you're using no-clean ("can't clean") paste instead of water soluble paste -- and they don't clog like unplated steel stencils. Unfortunately I haven't yet found a water-washable paste with a flux active enough to work reliably on cheap ENIG boards with >2000 pads. Kester EP256 is invincible as usual, but the residue is just as obnoxious as any other NC paste. Amtech 4300 tacky flux is miraculous stuff, still validating the paste version of it though (expensive!) but good results so far.

Unfortunately the chemicals used to do stencil nickel electroplating cheaply are really nasty so it's hard to get them from US/EU stencil makers... at least at a competitive price.

[jarekk]

Question - how do you prepare the paste ?
In about 60% of cases, after removing stencil the paste flows a bit and in case of fine pitch it causes later on shorts.

I would like to get get to a point in which the paste does not flow once placed on the PCB.
I have tried to leave it for hours in room temperature, then mix before using. Usually I get few boards like then and remianing one are messed a bit.

Only one paste was always such good - but it was bismuth based ( fwith about 180 deg melting point - used for dual component boards).

I do not solder very often ( just few 100's a year), maybe somebody with more expirience could help..

[mrandt]

1. Make sure the stencil apertures are adequately sized. The thicker the stencil material, the smaller they need to be to get the correction volume of paste onto the pads.
If you have maby shorts, you might be using tio mich paste and may need to shrink the "holes" in the solder paste layer in your ECAD.

2. I can recommend Henkel Loctite GC 10 solder paste, which is the only RoHS paste I know that can be stored at room temperature and thus won't suffer any thermal effects while handling the PCBs.

Hope this helps!

[Roche]

Clean stencils are vital - I clean with solvent and dry between each print. Compressed air is good, if it is available.
I use Multicore 96SC LF318, and see very little slump even after 3 hours.

[jarekk]

Thanks a lot. I will try to use compressed air on stencil and dry it more then usuall.

Any idea where to buy these solder pastes in smaller quantities then 500/600g ? I do not use that much in reasonable time

[Roche]

I keep the paste in a refrigerator and have some with a use by date of 2014 - it still works fine. Farnell do syringes, but not of that particular paste.

[jarekk]

Ok, I will try then this Multicore 96SC LF318 - we do have a fridge, so hopefully it will live longer.

http://pl.farnell.com/multicore-loctite ... dp/1257149
http://www.farnell.com/datasheets/16839 ... 1434007618

I will split the original packing into 100g jars and vacum pack them until needed

[jarekk]

Ok, after all I got much better deal for Loctite GC 10 T4 in Digikey

Anybody interested in half of the jar ( 250g ) ? I can pack and ship easilly ( and cheaply) around Europe