[OT] Reflowing PCBs in toaster ovens

Georg Acher has done it. The web page describing it should be at

I have tried bga with an 8 ball 555 timer chip. It did not work because I did not have a soldermask. As a result the solder wicked along the traces and part did not settle properly. Still based on what I saw, I think BGA's are quite doable for the hobbyist. Once I get someway to produce solder masks I wll resume my experimentation.

Why not use a commercial board production service? Most of them offer special pricing for prototypes. Many of them offer discounts for educational projects.

I mostly use Advanced Circuits,

Hello Lewin,

Did you ever try the barebones process? That looks like a good deal.

Now if they'd take Eagle files that would be even better. Well, maybe some day. At least they aren't tied to a proprietary tool set but it seems to be plain Gerbers and that is good.

Regards, Joerg

Just do a web search. PCB Express

I like it that PCB Express accepts Eagle PCB files directly. That saves me some hassle and seems more error-proof. The prices are high, especially for 4+layer boards with solder mask and silkscreen. I think a board with a small (up to 256 balls) BGA chip will require more than four layers. And having more layers not only helps with bringing the signals out, but also allows you to do a better SI design since the layers are closer and the tracks can be narrower for the same impedance.

-- Georgi

Are you saying that

I went to their web site and didn't see any service offered to attach IC's to the PCBs.

I am look>>Still based on what I saw, I think BGA's are quite doable for the

If you're looking for a low-cost PCB service to do BGA stuff, be sure to read the requirements carefully. IIRC, many of the low-cost services will not handle traces less than 0.008 inches and will not do blind or buried vias. While I have not yet had to do a BGA design, I think those constraints might render the layout more difficult.

Mark Borgerson

Hello B,

In my experience it is easier to hire a local tech as a temp for that. The hassle of shipping bags of part to the assembly place and then back causes too much cost and trouble. Of course, with very large SMT boards that's a different matter but even then I still try to find local providers. Distributors know where they are.

Regards, Joerg

prototype

if

No. The things I'm doing tend to be rather large boards; they're cheaper at $33 each in the quantities I need them. But I don't see why the quality would be any different from the 33each deal.

I use Eagle for all my design work. I'm used to generating RS-274X and Excellon anyway because my archiving process requires them.

They're a PCB house, not a CM. They have links to some CM people they recommend. But we were talking about PCB etching, not contract assembly. For prototype quantities it's better to assemble in-house by hand anyway so you can test the board during bring-up. Case in point, the project for which I received boards yesterday had a short from +5V to gnd (my stupid layout error). Would not have been able to fix that with a simple track cut if the board had been completely stuffed.

Ditto. Great quality, IME. They've consistently met expectations. And they waive the 3-piece minimum for educators and students. They also started including 2-sided silkscreen in the 33each.com deal, where others don't. For a reasonable $50/batch you can do multiple parts per

I've found that everyone's "hot deal" comes out to $100 a job, minimum (excepting Olimex). So, unless you really need more than 3 boards in a spin there's no reason to look elsewhere, especially with Advanced Circuits' tolerances, quality, and turn time.

But for any volume of tiny boards with mask & silk, Olimex seems to offer the best deal by charging by the area, not the piece. Trade-offs are longer delivery time and lower tolerances - IIRC, Olimex only does

Good for a quick spin. I can live without the silkscreen, but I wouldn't enjoy the SMD soldering without mask.

Here in Europe, both PCB-Pool and Olimex accept Eagle files.

Leon

good,

because

There are plenty of PCB houses, but I recommended AC because I use them regularly and trust them. They've always given good quality results, and I like their automated pre-analysis (freedfm.com). Plus they are very intelligent about suggesting solutions/fixing problems where necessary.

There's another vendor I use occasionally, but darned if I can remember the URL off the top of my head, I'd have to go through old invoices. This other vendor does the work in China; they batch up the boards and send them to their US HQ, and the US HQ breaks up the mass shipment and sends out the individual packages to US destinations. They are pretty much 2-week turn minimum (they have faster services but they're expensive). The other vendor is cheaper than AC and the quality is good, but if I need something in a hurry (like my most recent board) I go straight to AC.

software

This kind of service is a total non-starter for me. Even if they had Linux-based software, which I'm sure they don't, it is totally unacceptable to me to have my files tied to a specific vendor. Might be OK for a onetime hobbyist project, but I don't do any projects like that; even my personal projects are built with the assumption that they might go into production (or that they might be saleable IP, which is worth more if it's totally vendor-neutral).

Hi Leon,

Yes, but the freight charges and times would be a real issue for us on the other side of the pond. Within the US there is so much competition that freight is just a few Dollars and they try to beat each other in speed. Even the postal service joins the game at times. When I bought a round of Olimex MSP boards from their US distributor recently I had some time so I chose mail. It took a couple days or so and the postage was $1.06.

Regards, Joerg

Last I saw PCB-Pool (also known as Beta Layout) had two operations in the US for East and West coast, best to check their site for exact details.

Hi Paul,

They do have a US phone number but it seems that their facilities are in Europe. That could mean higher shipping charges when compared to domestic suppliers.

Regards, Joerg

Hi Richard,

AFAIK the smallest standard drill size at Olimex is 28mils (0.7mm) but that decreases a bit with plating. Pretty big. They do allow you to panelize and even cut the sub-boards up for you which is nice.

Does anybody have experience how their lowest cost ($9) airmail parcel option works into the US?

Regards, Joerg

That brings up a related question -- what Linux-based vendor neutral PCB layout software do you use. And if it's different, what would you recommend?

Ed