Just to let you know what lies ahead....
If you want to go from making a hand-built breadboard or prototype to actual PCB's, you have a lot of hours and anywhere from several hundred to a few thousand dollars cost in front of you, depending on how much you are willing to do yourself.
Schematic capture and PCB layout
First of all you need to capture your design using some sort of schematic capture program, and then design a PCB. One of the more popular programs is EAGLE, which I use. They have a EAGLE Light version ($49), but it can only be used for schematics with one sheet (any size), two signal layers, and 100x80mm (approx 4"x3") routing area. For any serious work, you need at least the EAGLE Standard version, which costs $747. There are probably other less costly (even free) alternatives. There are lots of others that cost thousands or tens of thousands of dollars. In any case you will have to spend considerable time learning how to use the program.
Or you can pay someone like me to do it for you ($$/hour).
PCB Fabrication
Getting boards made is the next step by a PCB fabricator. The problem here is the NRE (non-recurring engineering) costs. Some board houses treat this as a separate figure, and others built it into their per-board quote. In any case, it is almost never economical to have just a few boards made. You might spend $100 for two boards, and $500 for 25. You need to have really large quantities to get down to just a few dollars per board.
The gotcha is, if you make 25 boards, populate just a couple of them for testing and find they don't work (and there is not an easy fix -- e.g. because you laid out a connector backwards), you might end up throwing away the other 23 blank boards away and you would have been better off just getting two. I have stacks of blank PCB's as evidence of this phenomena.
PCB Assembly
Unless you are willing to build the boards by hand, you will need to have them assembled. Surface mount packages are difficult to deal with. If the board has BGA or QFN packages, you probably won't be able to build them yourself unless you have your own reflow oven.
Getting your first two boards built by an assembly house might cost $500. Whereas getting 25 built might cost $1200. (Once again, the problem here is the NRE costs.) Getting down to just a few dollars per board requires (again) large quantities.
And someone else has already discussed the problem of getting parts.
Make sure you use parts that are readily available -- if both DigiKey and Mouser have hundreds of the part available you should be okay. If instead, they have it in their catalog, but it is currently out-of-stock, try to find something else. If you need some special parts that aren't carried by DigiKey or Mouser, make sure you have a reliable source before incorporating it in your product. (Note: the more unusual parts you use, the more likely you will have to add the part manually to your PCB parts library.)
Custom Cases
Do you want to put your board into a case? If you need to have a custom case designed, that will be a couple thou for the designer using a program like SolidWorks (I don't do that, but can recommend someone who can). If you are going to make just a few cases to begin with, you will probably need to go with rapid prototyping, such as Selective Laser Sintering (SLS). Figure at least $100 per case in small quantities. To get down to a few dollars per case cost, you need to have a custom mold made. NRE time again! Plan on spending $10,000 or more for the mold.
And I won't even start on EMC or EMI testing, since I don't know if it applies to your product.
As you can see from all of this, until you get into production, the cost of the electronic parts is usually not the biggest item on a per board basis. Doing your own assembly for small volumes will save you a lot of money. So it is important to design with that in mind -- no impossible to solder-by-hand parts.
To get really low prices for high-volume, generally you need to go offshore -- China etc. But I would avoid doing so in the beginning.
In my industrial experience, the way things generally go in terms of a design cycle follow this sort of flow (condensed version):
- Market research/contact with a customer (identification of the what the basics of the product should be)
- Establishment of a specification (or "spec" as it's often abbreviated)
- A formal quotation and business agreement between the parties (or between engineering and marketing for a 'standard' product)
- Initial design / calculation / simulation / debugging
- Design validation testing, or DVT (you making sure the product meets the spec)
- Bugfix implementation / regression test
- Independent DVT (someone else making sure the product meets the spec)
- Safety and regulatory approvals
- Design for manufacturability review (DFM)
- Production release / marketing release
If you have a project that you've developed, and you feel you're ready to market it, you may want to consider some or all of the following points:
- Write a spec if one doesn't exist. Characterize the typical performance of the product and put this in the spec, as well as any absolute maximums or minimums in terms of 'externals' (volts / amps / degrees) that should be avoided.
- Make sure that your product meets your spec. Do a formal DVT and make a report of the results. Also, test a quantity of boards against the spec and use statistical analysis (Cp/Cpk) to prove that over tolerances and normal variation, you product can do what you say it can do.
- Come up with a reduced number of tests to perform per-unit as a manufacturing reliability test. Bad builds, bad parts, new operators, bad equipment can all lead to problems.
- Make sure that your PCB has in-circuit test pads on as many nets as possible to facilitate in-circuit test (ICT) or manufacturing defect analysis (MDA) - finding problems earlier rather than later is always beneficial.
- If this product is intended to be high reliability, you may want to perform a life test. Run a quantity of units perpetually until something fails. There are industry standards on life testing (acceleration factors, lot size, etc.) which fall beyond the scope of casual advice.
- Consider HALT (highly-accelerated reliability testing) as well - testing the product under thermal and mechanical vibration stress can show weaknesses in the design as well as its construction.
Many of these sorts of tests are big bucks. (Tens of thousands of dollars per test). The cheapest things you can do are those that you can do yourself - the spec, the DVT test and statistical analysis, test pads on the PCB, for instance.
You may wish to consult with an experienced manufacturing engineer to figure out what you really need to do, given your budget and the expected revenue of the product.
Good luck!
Best Answer
My experience is not exactly what you describe, distributors are there to deal with the small to medium customers that the factory does not want to directly service. For instance TI doesn't care much if you want to buy 1000 MSP430 chips, but digi-key might, or maybe even Arrow. So unless your volumes are large, or the factory is small you will not be buying direct from the factory, that choice has already been made for you :) If you were able to buy parts direct from the factory I would not expect a problem with counterfeit goods, just as I would not expect one from say an Arrow, Avnet, Future, Digi, Mouser, etc. Those are examples of large and franchised, or authorized distributors for various components. (I'm using factory the way buyers and distributors use it to mean the manufacturer such as a TI, or Samtec for example).
Someone may know otherwise but I've never had a distributor test parts for me, although I have had them program and test things like flash or MCUs. I suppose if I complained they would be able to charge me for such a service but I don't think that is routine. It's the factory's job to test their components before they ship them. As such if you have an issue the disti will point you back to the factory for such things. If you are a good customer, and you're angry, they may take the parts back directly and work it out with the factory themselves, but probably not.
I've never seen any online reports about distributors, they may exist. I tend to stick to people I know and I've worked with in the past such as the names I mention above. That said there are lots of smaller distributors around the world, and my only word of advice is if you suddenly find yourself getting a great deal compared to the other quotes you've received perhaps it's too good to be true :) Another thing is I prefer to try to foster a good relationship with the distributors I do use.
For the last question I'll break it in two. If you bought parts from a franchised or authorized distributor, and they turned out to be fake, that disti would have a lot of explaining to do. In that case I would expect and demand a full refund, and might even demand compensation for damages if it was serious enough. If you got them from another source, say a broker, an unlicensed distributor, another CM or god forbid ebay. You're pretty much screwed.
One of the things I've noticed lately is that large CMs are selling parts they're buying at a volume discount out the back door through various brokers or agents. In fact there seem to be whole companies that have sprung up just to support this. I personally think that's a dangerous game to play if you're worried about quality and genuine product, but it does seem to be popular.
Now what if they don't work or half work after you've assembled them? Assuming you have bought authentic parts from an authorized disti or the factory then the factory should engage you to help do failure analysis. Now your mileage with this will vary depending on how good of a customer you are, and as a small guy you may spend some time talking to the disti's support team to make sure it really is a failed part. Once it's done most people will engage you because it's in their best interest to catch and understand any field failure.
A few notes on that process, one it takes forever, you may be better off analyzing it yourself at a lab and sending them results and samples of the failure. Two there can be a lot of finger pointing, the CM says it's the factory, the factory says it's the CM, or they both say it's your design or spec. So you have to stay on it to find the answer, and of course be open to the possibility that it is in fact your fault. Finally the level of support you get here will vary based on what factory/manufacturer you are dealing with, your relationship and volumes with them, and indeed the region you are in. So while I have seen for example linear tech jump at every problem I've ever uncovered and sent their way, I would hardly expect that kind of service for the $0.10 regulator I'm buying from an overseas off-brand.