I'm trying to decide if it would be worth it to farm out the assembly of
small production runs of 20 or so boards (150 components) or build
them myself. This will never be a 1000 unit or even a 100 unit deal.
At most I think 10 units per month is what I will be assembling.
I've assembled a lot of prototypes and I'm decently quick but have
never just done a grind of 10 boards, I assume it's much less enjoyable.
If you've done this, would you do it again?
What types of problems did you run into?
Did you find it less expensive in the long run just to pay an outside company to do the assembly?
I have just done a run of boards myself to help keep the price down and it was a grind to do them, but it is made much easier by preparing everything properly beforehand.
I get a separate bunch of components ready for each board before I start soldering , with all the leads pre bent as necessary and all in the right order for assembly, so the lowest profile parts go in first.
I use automotive masking tape to stick them to the board and keep them in place when it is upside down.
All I need then is a radio & a regular supply of coffee and I am happy.
Watch out for signs of RSI though. My hands are shot through years of wiring control panels and now a couple of hours at the workbench and one of them stops working properly. It is difficult to describe but it feels like I am wearing boxing gloves when I try to pick anything up.
Could you earn more money by doing something else?
Yes, I do plan to sell them and your point about time is well taken. I
think the biggest reason other than cost that i'd like to do these
myself is the control over the product and the fact that i can change
the design every 10 boards and don't have to worry about the 90
sitting on the shelf if I had someone else assemble a batch.
jabber: i also have hands that get painful after a while and these are
all SMC 0604 and even some 0402 components. I guess i should
have mentioned that as well, the smaller sizes do slow you down a bit.
I find that SMD based boards are a lot faster to assemble than through hole boards. I'll usually sit down and assemble 5 - 10 boards a night.
You definitely need to have all the parts well organized. Put them in small bins in the order you will be using the parts. Most of my time is spend applying solder paste since I don't have a stencil for any of my boards. I would recommend having a solder paste stencil made. Once the paste is applied, things go pretty quick. I use tweezers (the reverse locking kind) for all the small parts and a suction tool for the bigger chips. I rarely use a magnifying glass, but it is necessary. I keep several toothpicks handy for adjusting parts instead if getting the tweezers full of solder paste (makes them sticky). Once you parts are on, either throw the board in an oven or go over it with a hot air gun.
For testing/programming you will want to make some sort of jig. I usually just wire up a perf board with some pogo pins (spring loaded contacts) and some alignment pins and then clamp the board down to it. You can then test whatever you need to without having to solder or clamp a bunch of wires.
With 150 components I would guess about an hour per board once you get good. But that really depends on the components.
If you need 50, then someone may be willing to moonlight. 10 is not very attractive. You will need to invest on equipment to improve your efficiency so some additional cost. If you want to do this, get a fume extraction station like this one on jameco. May help with health issues:
I guess for 20 pieces, it's never going to be cheap to send for assembly outside (whether it's local or offshore). Try settling on using whatever tools and methods that could help in assembling them more efficiently (use home made reflow oven and stencil). 150 components is quite a lot and tiring for hand solder.
