SMD More Reliable Than Thru-Hole?
No subby here in the UK would guarantee anything - unless they build the whole
product (and they supply the parts). I free issue the parts - it is a lot cheaper
for me because I avoid the subby's "cost plus" margin, I have quality
control over where everything comes from, and I can build small batches of something
without having to pay the subby to buy a reel and waste most of it (if I use
the part elsewhere).That's exactly what they do. We supply the gerbers and the
ATE jig and help
>develop the program and they do parts procurement, oursource board manufacture, and stuff/test. We buy complete tested boards from them with a 1yr warranty.
You can call me paranoid :) but I would never ever ever do that - I would never subcontract that vital last step (final test and inspection) which ensures that you never send crap out of the door.
It is OK to send out occassional crap (everybody does it, even me *very* occassionally :)) but if your subby messes up big-time then you might send out a complete duff batch, and your customers will never forgive you because they will "realise" that you don't give a damn.
Almost everybody will forgive an honest mistake (and, business wisdom says, customers who had a problem and had it promptly fixed are more loyal to you that customers who never had a problem) but nobody will forgive a whole defective batch.
Almost every subcontractor I have ever used employs a bunch of low-paid people who can make a huge mistake as easily as drinking a pint of beer, and they give it about as much mental time.
That's why I am happy to sub out PCB assembly but never the test and inspection. Not to a small firm. There are lots of very big subcontractors but the very big firms have the QA systems in place ( except those who make Sony televisions and laptops nowadays :))
There are also detail issues like fine-pitch assembly. If the PCB manufacture isn't wonderful, and/or the pasting/soldering isn't wonderful, you can get weird long term reliability problems. I personally 100% inspect all TSOPs with a $6000 microscope - it only takes me 2-3 hours per month and I spot a lot of interesting stuff. I now buy boards only from China - nobody here in the UK can do the quality consistently (regardless of price), and I've been in this game for 24 years.The reason I free issue the parts is to avoid the subby's 20% (minimum) mark-up. Let's say your annual sales are $500k; by free-issuing the parts you save $100k at least, and it doesn't take a lot of effort to do the purchasing if you use a relatively small range of parts (normally the case if your products are all designed by yourself)
I'm not sure what the cost per placement is as I'm not in purchasing but I believe a current mixed smt/th board we purchase is USD$125 and includes about 300 components (about 50 th) -- unfortunately I don't know what the parts cost is ATM so I can't get you a cost per placement. I'm really curious about it now. :-)
It's all pros and cons. Lots of businessmen will say that subcontracting the whole thing enables them to concentrate on their business. But lots of businessmen are wrong a lot of the time. The point is that by doing a relatively small amount of extra work in-house, you can make a whole lot more money. And what is business about? It is about making as much money as possible, while living as long as possible :)
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M-à-j: 25 septembre, 2009