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SMD Soldering without Soldermask? Answered

I'm working on a project and I needed to get a PCB made. I was planning on getting it from BatchPCB, but I ran into a little problem... I'm using a NAND Flash chip, which is TSSOP48; the footprint has 6mil spacing! (BatchPCB has a 8mil minimum) The next cheapest solution would be Barebones PCB, which makes prototype PCBs without soldermask & silkscreen. I'm worried about soldering on the Flash chip, and another LQFP48. Will the lack of a soldermask make it impossible to do?

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flyingpumpkin (author)2010-02-17

www.renaelectronics.com/picts/howto/stencil/movie_0001.wmv 
you can manufacture a soldermask with this kit from renaelectronics.  It is a DIY kit that lets you etch thin metal plates... and it is cool.

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westfw (author)2008-09-20

I find lack of soldermask a pain for SMT components. You are to some extent relying on the surface tension and adhesion of the solder to the pads to make up for impossible-to-hand-solder dimensions, and with no soldermask, the pads don't END...

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guyfrom7up (author)westfw2008-09-20

yeah, but you don't NEED it, lol When possible it's nice, but many people do SMD soldering on homemade circuit boards I've only soldered on manufactured pcbs twice, and I will admit, it was NICE

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zachninme (author)guyfrom7up2008-09-21

I'm just really worried about these package sizes. I've done [the SMT Atmega168's (I can't recall the size) on both homeade & "real" pcbs, and I could feel the difference. The NAND Flash chip has 6mils between pads. It was hard on a "real" pcb... I wanted to know if it would be significantly harder on something like this. And even the best homeade pcbs (that I've seen) don't go down to 6mil.

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westfw (author)zachninme2008-09-22

I would consider a soldermask an important part of a commercially made board, and that it would make soldering fine-pitch stuff significantly easier. I'm not arguing that it's POSSIBLE to solder SMT without the mask, but it would certainly be harder. You should be able to find a PCB maker that does 6mil clearance AND soldermask in their prototype service...

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zachninme (author)westfw2008-09-24

Actually, I realized that AC's 33 each special w/ the student discount would end up being cheaper than their barebones service if I only get 1.

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guyfrom7up (author)zachninme2008-09-24

really, can you give me a link?

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zachninme (author)LinuxH4x0r2008-09-21

These are custom boards, that seems too expensive... I could probably get real prototype-quality boards for cheaper...

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LinuxH4x0r (author)zachninme2008-09-21

I got 2 samples (with amplifier chips!) for free, so I'm happy. I suppose they might get pricey

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zachninme (author)LinuxH4x0r2008-09-21

Ah, now that I'm looking at them, I understand it... I didn't see that you just buy it for a specific size, I thought it was like a PCB...

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LinuxH4x0r (author)zachninme2008-09-21

Actually it is like a pcb, thats just one version of it

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guyfrom7up (author)2008-09-20

nope, infact hobbiest don't even need soldermasks, the main purpose of a soldermask is for when big companies do wave soldering (where they pretty much dunk the board in molten solder). Another plus of a solder mask is that it prevents corrosion. as for SMD soldering, you do not need a solder mask.

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