SMT manufacturing

[daveq]

I've used a company in CA for some PC board manufacturing but I don't think they offer surface mount population and soldering. Does anyone know if there are places that offer the service for small projects?

[lovekraft]

Don't know anybody who offers it, but you can do it yourself - Ansil uses SMD parts in some of his boxes, and says it's not a big deal (well, except I can't even see the pins on the ICs - gotta get a good magnifier). Here's a couple of links to DIY SMD:

How To Solder & Desolder Surface Mount Components Simple tutorial

Prototyping With Surface Mount Components Overview of tools.

Soldering SMDs

PCBs with SMT Components

Numbnut's guide to soldering Surface Mount devices How to"...Become a fearless soldering God..."

[daveq]

Cool!

I don't exactly have surgeon like hands but I'll check those site out.

Thanks!!

[ansil]

it depends on what you are wanting to do i build simple gain devices with smt chips and some of there resistors. for the most part i did it becuase my boards cost me like 11cents each if i get 100 of them. thats a .5" by .75" board. with all my crap on it. shoot yeah i will bust out the magnifying glass. for that

make a few mods to your soldering iron and its a cakewalk.. you can make an extension piece to slide over the grip of the soldering iron so you can make quick joints with pencil like acuracy.

[daveq]

I'm going to give it a try later tonight. I've been asking around here since I work at a place that manufactures electronic devices and some people seem to think that a bit of adhesive placed under the parts and thin dia. solder should do the trick. Does that sound right to you? I'll be soldering 2x3mm capacitors (and some 3x5mm caps as well).

I haven't read those links yet Lovekraft but I certainly will before I fire up the iron. The reason I'm posting now is that I'm interested in the trick that ansil is talking about. Can you describe what I need to do to the iron to make those quick joints you were talking about?

Also, do you know if I'll need to turn down the temp more than usual? I have been setting the iron to a temp that just melts the solder (just a bit more) but I'm not sure if that's good practice or not?

Thanks for the help,

Dave

[lovekraft]

The glue-on technique seems to be used quite a bit - I know of one guy who steals his wife's little pink "crafter" hot-glue gun to stick the resistors and caps in place. I wouldn't worry about changing the soldering iron's heat setting, what works for thru-hole PCs works fine (in my limited experience).

[ansil]

i use basic super glue. when i have to do the resistors and such but actually its quite easy once you get the hang of it to pool up some solder. and drop the part in with a pair of hemos

i made a nice littel hand grip that slides down over the the actuall soldering iron. its a little larger than the actual handle of the iron and its pvc and then theres a piece of mesh steel kind of like whats on those hughes and ketner amps that you can see through. and some industrial oven mit padding on it. so only the tip of the soldering iron is expeosed.

[psw]

I'm making a hex piezo pickup system...got the pickups down but would like to make the preamps (six) really small and low power, possibly built into each driver to minimize noise.

Any ideas on this, or circuit ideas involving SMT components would be much appreciated

Pete

[ansil]

six smt lm386's. all you need is v+ ground and a gain resistor. makes it pretty darn small my boards are tiny now.

[daveq]

I did my first SMT/SMD (which is the proper acronym?) board a few days ago. I was surprised at how well it went. It took a little time to superglue the parts in place but after that, everything was pretty easy. I don't know how well I'd do at a quad opamp chip or something that has pins right next to eachother but for caps and resistors, no problem.

Thanks for the great advice.

Dave

[ansil]

glad it worked for you dave

[psw]

Thank's Ansil...

no need for output caps, etc? Just the chip with gain control!

[lovekraft]

six smt lm386's.  all you need is v+ ground and a gain resistor.

Surely you're bypassing the V+. I can see not worrying about an input coupling cap with piezos, there's no DC to block, but without a good-sized power supply bypass cap (for each chip), won't you get screaming oscillation as the battery goes dead? Also, do piezos have enough output voltage to drive a 386 without a gain stage or at least a buffer in front? Sorry, it's just that my "inner engineer" is screaming, "But that's not the way we were taught!", so if it doesn't matter, just ignore this.

[ansil]

well an alternate route is to use 6 smt jfets and all the rest of the parts. i was just giving a basic suggestion.. but hten i reread the post and for a pickup system i missed that and was thinking of the drivers.

[psw]

Thanks guys

I thought the 386's weren't quite what I needed for PUps...food for thought though for the drivers.

What about electret mics...don't they have an inbuilt FET amplifier on board that could be adapted?

This will form a part of the sustainer system, provide acoustic sound and possibly some other stuff like very basic A/D conversion for sequencer programming and notation software (well, maybe in the MKII version).

[daveq]

OK, I found a place that will manufacture surface mount boards (with components). They look similar to other online circuit board shops but the big difference being that they will include the population of components. The catch (of course there's a catch ) is that they are a bit pricy.

The site is Pad2Pad.com

With the help of lovekraft and ansil, I don't really feel like I need to pay someone loads of money to do something that I can do on my own but I wanted to share this info with you guys anyway. You never know when you might come up with something that you'd like produced.