Lessons Learned Going Beyond Arduino - Professional Assembly

So I thought I'd pass along some experience I've learned in the last year or so on my project in regards to professional assembly.

I started my project off on breadboard, moved to perfboard, then to a "stitched" together PCB. By stitched together, I was taking various breakout boards to create my circuit. I created a custom PCB for my various breakouts so that I didn't have to wire traces together.

Easy right? Yes. But my costs were "high" since I was buying pre-made breakout boards to make my circuit. I eventually decided to scale my hardware by ditching the breakout boards. I instead decided to have my own PCB designed and use the raw hardware components. I was thinking... well if I can get a PCB from JLCPCB for $.50 and get raw hardware components I should be able to save some major costs.

Well, I vastly underestimated the cost of assembly.

I saved money on my hardware (about 50%), but my $.50 JLCPCB board went to $80 assembled. Of course, I'm doing "short-runs" and only having 6 made, but I honestly didn't realize it was that expensive.

So.... in case anyone decides to go beyond breakouts, think REAL hard about your goals. If you're ready to sell thousands of them or you have a buyer ready to pay high costs at low quantity, go for it.

Otherwise, the breakout boards are the way to go. You COULD of course hand-assemble, but you'll want to invest into some equipment. Even then... some components are very small and difficult to place even with a stencil.

I honestly wish I knew this before I spent a lot of time designing a board from scratch...

I am looking at designing a board for a project- not to replace anything but to clean up the rats nest of wires connecting the boards and a few external components.

What software did you use to design the board?

EAGLE

The major expense is when you have the commercial assembly house place the thru-hole components. These are always hand work and if a low volume, are also hand soldered. Then there is time to prep the components, ie, clip and form the wire leads. Our rate is $65 per hour.

Some of not all the cheap assembly is ONLY SMT. I know Screaming Circuits has sent us customers with lots, fi not all, thru hole assembly. They just won't even give a price to the customer.

Paul

From time to time here we get people intent on "making their own" Arduino.

Unless you are going into production - 1000 units to start - and very few people here are, it is a fool's errand.

A Nano - or a Pro Mini depending on the requirement for the USB interface - is already a functional building block. Considering the price of the cheap - and generally perfectly functional - Chinese modules, the inventory will generally cost more than the Chinese-produced modules, let alone assembly costs. So this you mount as a daughterboard, either using the pins or a socket.

Now for other small components the situation may differ.

If you have a reflow oven doing your own SMD assembly is not that hard. With a stencil it gets quite easy to get the solder paste right. I've not gone smaller than 0805 for resistors/capacitors (small enough for me), but an attempt to do QFN parts recently failed utterly... gotta ask Seeed to do that one I think. TQFP has worked quite well for me.

By doing the assembly yourself the cost isn't that high, but of course it's a couple hours work so only cheaper if your time is cheap.

OTOH I've also done several PCBs with e.g. a Nano and DF Player soldered on, or a Pro Mini with a stepper, made it really easy to assemble. The other components on that board were a bunch of big capacitors (electrolytic, so THT; all placed horizontal, with some slots in the PCB next to it for a cable tie to hold the thing in place) and a number of connectors which of course have to be THT for strength.

It depends on what you want to achieve.

Well, my intent was to cut costs as I had a handful of people interested in my product offering.

Naturally, I tried to cut costs by getting rid of the “middle men”. Unfortunately, I traded one middle man for another... and the other (to your point) only saves costs at MOQ of 1,000+.

I never wanted to build another Arduino though. This industry (micro electronics) is an interesting and frustrating industry. I almost feel like to escape hobby is to build only “must have” products rather than “nice to haves”.

At least for entrepreneurs/inventors like myself.

Typical setup cost for manufacturing a small board is about USD 250, which is regardless of the number of you produce.
Then there's the cost of making a PCB - that depends a bit on the size and quantity, plus the cost of the components themselves, which is also highly dependent on volume: in volume the per piece price can go down by 50-80%.