Accurately locating SOT-23 parts

Dec 16, 2013 49 Replies

It's not hard. Just old and fairly worn down SMT pick&place machines running flat-out all day long. I have an example here from a product with qties in the millions/year. No, not from a client. And they all work.

You need to get out more :-)

Regards, Joerg http://www.analogconsultants.com/

Millions per year requires *better* tools or the losses will kill any company.

I meant that if their production is that sloppy, given the overhead of the toy market and the losses they *must* be taking from such a s***ty process, they're not making any money.

If almost none of the more or less skewed SOT contacts ever fail, what losses?

I know they are making money.

Regards, Joerg http://www.analogconsultants.com/

Joerg is right. A cheap wireless doorbell from China which I have has components which appear to have been mounted by a deranged orang-utan on acid. Clearly very badly machine built with gaps bridged by cheap labour. It works, ship it.

Even my very old stereo amplifier is a lesson in ugliness. All through hole with vertical resistors at all sorts of angles and lead lengths.

Cheers

Syd

One of my examples here isn't even cheap stuff, it is a board from a fairly popular cordless telephone system. The kind that retails for around $80-$100 at the usual discount club stores.

Regards, Joerg http://www.analogconsultants.com/

I saw a tear-down of one of the fake phone chargers, it looked like the assembly process was done by trowing components at the pcb from across the room and soldering it with a bent nail heating over a bonfire

-Lasse

The parts are EXTREMELY cheap in this sort of spew. I've heard of 20%+ fallout rates. So cheap they ship such lots untested to India at a big discount (where it's worth their time to sort or fix the bad ones).

You can buy untested microcontroller dice, since testing adds a tiny amount to the cost, and just slap it on a COB and throw the whole thing away if it appears to fail at room temperature and with a nominal battery voltage. Of course a small percentage will _just_ work and will fail when the room temperature drops or whatev..

The boards, even 2-layer FR-2, aren't. I'm not buying 20% scrap, either. 2% is enough to bankrupt anyone.

You're going to mount bare uC dice on a process where you can't place parts within .5mm? Good luck!!

Stamped paper-phenolic boards are priced by the square meter. A 5 cent bare board is not unusual, and I expect

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