SparkFun Forums

[iled]

LEDs are through hole. I couldn't find SMT RGB LEDs cheaper than a $1 or so, and I didn't want to shell out $256 per tile of LEDs. I have yet to make the board, so I can put a solder mask on there if need be. It will also probably be a large board, 8 to 12 inches squared.

Anyone have a recommendation on an assembly company? It's a prototype so it doesn't need to be anything professional.

What about a solder pot? Is such a thing recommended?

Can I use a wave solderer with through hole?

[propellanttech]

LEDs are through hole. I couldn't find SMT RGB LEDs cheaper than a $1 or so, and I didn't want to shell out $256 per tile of LEDs. I have yet to make the board, so I can put a solder mask on there if need be. It will also probably be a large board, 8 to 12 inches squared.

Anyone have a recommendation on an assembly company? It's a prototype so it doesn't need to be anything professional.

What about a solder pot? Is such a thing recommended?

Can I use a wave solderer with through hole?

You could use both, a solder pot (manual fluxing/dipping) and Wave. That is what wave was designed for.

You may have a problem finding a solder pot that large, without shelling out some major $$$.

It may be cheaper to go with the SMT LED's in the end.

James L

[iled]

Does SparkFun have a recommendation for an assembler?

Also, does anyone in general have a recommendation of SMT RGB Leds?

I found these on ebay:

http://cgi.ebay.com/NEW-500-PCS-PLCC-6- ... .m20.l1116

But I am always wary of ebay...

[macegr]

I have a bunch of those exact LEDs from that supplier, I am using them on the OctoBrite seen below. They are actually kind of painfully bright, though red is a bit dimmer as is so often the case with RGB LEDs. The center hole is filled with soft optical silicone instead of hard epoxy.


I made an Eagle part for the LED, so let me know if you decide to go this route. Figure out how to make a stencil (I use a laser cutter), grab some $4 solder paste from Dealextreme, and you could build this in no time.

[lyndon]

I guess I'm having trouble understanding what the problem is. Soldering 1000 through-hole connections isn't very difficult or time consuming.

1) Stuff board
2) Place conductive foam on top of board to hold parts in place
3) Turn over and solder center lead of each LED
4) Flip over again and verify all LEDs in correct registration. Correct the ones that aren't
5) Flip back over and finish the 3 remaining leads on each LED and then trim to length.

That's 2-3 hours of work tops. All this talk about solder pots and farming out for wave soldering is only necessary if you're doing a large volume of them since the setup charges for a handful of boards will overwhelm the actual assembly cost by far.

[bigglez]

I guess I'm having trouble understanding what the problem is.
...
All this talk about solder pots and farming out for wave soldering is only necessary if you're doing a large volume of them since the setup charges for a handful of boards will overwhelm the actual assembly cost by far.

Rereading the OP:

I'm working on modular LED display, composed of LED tiles, each of which will require 256 throughole RGB LEDs. What's the easiest way to solder all of them on? There are 4 pins per LED, so I'd rather avoid doing it by hand.

So, there are multiple tiles? Each with 256 LEDs...
The unknown magnitude of this project might easily
justify some "designed for manufacturing" effort up
front!

[macegr]

My assembler charges about a penny per solder joint. I guess that means a $10.24 or $15.36 assembly cost plus whatever pins are necessary for other components on the PCB.

[propellanttech]

My assembler charges about a penny per solder joint. I guess that means a $10.24 or $15.36 assembly cost plus whatever pins are necessary for other components on the PCB.

Wow, can I ask who your assembler is?

You didn't say if that was a panel, or total. sounds real good when you don't calculate that is each panel.

If you have 100 panels done, that adds up to some money.

Does the assembler charge a setup fee?

I just quoted a person $775.00 for 500 boards with a led on one side and parts on the other. Not many parts, probably about 4. That quote included stainless stencils. But remember that is dual sided. Two times in the "Pick & Place".

James L

[macegr]

Well, $10...That's one panel...about a thousand solder joints per panel as discussed above, about a penny per joint x 1000....

I've produced several thousand of these devices, you can't see from here but there's a 3x3mm QFN-16 and a couple passive components on the bottom.

My supplier makes the PCBs, sources the parts, and assembles. There's a $50 setup fee, and if a stencil is needed, it's about $120. Then there's shipping, which can be pretty high. But breaking off the raw assembly cost, it's about $288 to assemble 500 of those modules.

It's OurPCB in China. Obviously it's going to be a lot cheaper there, but I could see events progressing in the near future that might make make a two or three fold assembly cost worth the "Made in America" sticker.