Fine pitch and BGA placement tool  - Page 1
Forum section: electronics / general

author: Otatiaro
author_rank: Regular Contributor
timestamp: April 12, 2012, 09:06:21 am
content: Hello,I used to assemble my prototypes myself, but it's getting more and more difficult ...Small components are not a problem, I even did 0402, but switched back to 0603 for convinence.No, the real problem is this QFP64 part (STM32F205) that is really difficult to put on the paste spot on.I'm also considering BGAs for new designs ...This is why I'm looking for the right tool to place fine pitch / BGA components.I need something simple, I have my PC on the same bench, so vido output or USB are not a problem, but room can be a problem (80cm x 100cm is by FAR the biggest useable area, but I'd prefer something a lot smaller).I'd prefer something not too exensive, of course.Any idea ? I found some products (from Essemtec, for example), but it's very hard to get a quotation ...I will also need a small oven with profile management, I saw this one which is cheap and seems to fit :http://madelltech.com/MD5001.htmlThomas.

author: kripton2035
author_rank: Super Contributor
timestamp: April 12, 2012, 09:31:01 am
content: the same oven for a lot money less ...http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110824856834&ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

author: Otatiaro
author_rank: Regular Contributor
timestamp: April 12, 2012, 10:49:05 am
content: Hello,Hell yes, a lot less money ....I did search a bit in their shop, and they have very cheap, probably not rigid enough for milling, CNC routers.They also have 4 axis control boxes (some of their CNCs are 4 axis) ... what if I remove the spindle, put the 4th stepper instead, and start a small, first semi auto, then automatic pick-n-place ?You think it's a good idea ?Thomas.PS : you'r french ? Do you have skype or MSN ? ;-)

author: free_electron
author_rank: Super Contributor
timestamp: April 12, 2012, 12:19:49 pm
content: Use a microstencil. No need for expensive tools. There exists a mylar adhesive stencil. You stick it to your board, spread some paste, peel the stencil off .Stick stencil to the qfn , spread paste , peel stenccil off.Now, using hot air gun : heat up the part so the paste melts. Do this on the part only. Your qfn will now have 'bumps'.Place qfn on the board. The bumps will keep it in place . Reheat. DoneWorks fine every time.I do even multirow qfns that way. I use a weller HAP1 hot air pencil. You can also do it with a cheapo aoyou handheld hot air blower.The stencils are made by a company called 'best'. I'll find you the link and post it here. I am working on a book that shows 'lab' techniques to deal with all this kind of problems. There are plenty other techniques .I am currently running an experiment to make flexible solder stencils dirt cheap.we are talking dollarcents for a 12*12 inch stencil. Of course they are not as durable as a stainless steel one, but you can make them at home.. The initial investment is about 200$ after that it's only consumables. And you can make adhesive stencils as well.As soon as i have finetuned it i will release it without secrets. What to buy and how to do it. And no there is nothing in there from my side.

author: Otatiaro
author_rank: Regular Contributor
timestamp: April 12, 2012, 12:24:26 pm
content: Hello,The stencil thing is interestingThomas.

author: free_electron
author_rank: Super Contributor
timestamp: April 12, 2012, 12:50:14 pm
content: Ill post some pictures later today...