Cheap prototyping solder paste stencils for QFP 100 - where? - Page 1
Forum section: electronics / general

author: DTJ
author_rank: Super Contributor
timestamp: April 28, 2016, 11:44:24 am
content: Are there cheap solder paste stencils for something like a 0.5mm pitch QFP-100?eBay seems to have lots of really super cheap BGA kits like these, 20+ for <Au$10:http://www.ebay.com.au/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR8.TRC1.A0.H0.Xrework+stencil.TRS0&_nkw=rework+stencil&_sacat=0...... but I can't seem to find similarly priced QFP-100 stencilsAlternatively has anyone come up with a nice method for laying down a bead of paste along the line of pads? Using a syringe I always seem to get too much or too little.

author: Spikee
author_rank: Frequent Contributor
timestamp: April 28, 2016, 11:48:08 am
content: Design your own for 20$

author: Jeroen3
author_rank: Super Contributor
timestamp: April 28, 2016, 01:53:28 pm
content: Use a pneumatic dispenser and the correct needle. I use 25g (red) for qfp.

author: mazurov
author_rank: Frequent Contributor
timestamp: April 28, 2016, 06:32:07 pm
content: OSH Stencils will cut you one from mylar for $5. You can also etch your own out of an old soda can.

author: wraper
author_rank: Unknown
timestamp: April 28, 2016, 07:02:11 pm
content: Quote from: mazurov on April 28, 2016, 06:32:07 pmMylar stencils for 0.5 mm pin pitch are basically useless. Also you cannot cut it from the soda can. 0.12 mm steel stencil is needed for such pin pitch to work well.

author: IconicPCB
author_rank: Super Contributor
timestamp: April 29, 2016, 04:23:22 am
content: I machine them in 0.2mm thick FR4 sheet.Send me Your Gerber I will send You costing

author: KE5FX
author_rank: Super Contributor
timestamp: April 29, 2016, 08:04:14 am
content: You don't need/want a stencil for QFPs. Look for some YouTube videos on "drag soldering."

author: DTJ
author_rank: Super Contributor
timestamp: April 29, 2016, 01:41:39 pm
content: Quote from: blueskull on April 28, 2016, 11:58:11 amYep, that's the way I've always done it. It always looks rough, I thought it might be worth trying a stencil.Quote from: IconicPCB on April 29, 2016, 04:23:22 amThanks, you've given me a good idea, I might try cnc'ing one myself using some brass shim.Quote from: Jeroen3 on April 28, 2016, 01:53:28 pmI've been laying the paste down using a manual syringe.

author: IconicPCB
author_rank: Super Contributor
timestamp: April 29, 2016, 01:58:50 pm
content: Wouldlike tohear of your efforts with brass shim.

author: KL27x
author_rank: Super Contributor
timestamp: April 29, 2016, 10:03:10 pm
content: Quote+1. Stencil for QFN, sure. QFP, why? You will easily be able to put a 0.5mm QFP on with an iron before you can even finish pasting the stencil. Doesn't matter if it's a one-off or x 1000.When there's hundreds of components on one stencil and a PnP machine, ok, now you're talking.Having no PnP, if I use stencil, I go out of my way to remove IC's like QFP, unless they're in an awkward location. As long as there is access, it's easier to put them on after the rest of the reflow. Less reworking/inspection. Also saves some cost on relatively expensive IC's, if you end up with excess boards and don't use them all.My personal magic is a 3mm CF tip. Not only works for drag soldering, it is a great all around tip for SMD work.

author: DTJ
author_rank: Super Contributor
timestamp: April 30, 2016, 01:05:26 pm
content: Quote from: IconicPCB on April 29, 2016, 01:58:50 pmI'll make an effort to try it out.

author: KL27x
author_rank: Super Contributor
timestamp: April 30, 2016, 06:19:03 pm
content: QuoteI used w/e tip came with my iron for the first 6-7 years in the hobby, now somewhat of a business. I can solder just about anything with a hot stick, no problem.But in hindsight, I wish I had not been so McGuyver all those years. They make different soldering iron tips for a reason!