I am also looking for a reliable service to print and assemble 3x10cm boards, using 0603 packages. Right now I could just order the PCB from elecrow (tried and verified to be just fine) and assemble by hand, but I figured I'll need to automate that process eventually, so it's a good time to wet my feet.
I thought about using elecrow 's service- it seems like a good deal and my specs are hardly advanced. My concerns are:
1. How "clear" does the design need to be for assembly to be smooth? For example, silkscreen is very tightly packed on mine- I have all the design files so I don't care that much (it's a proof of concept prototype), but will that lead to errors on their end?
2. I use very standard CD40xx logic ICs and TL0xx opamps. What kind of price should I expect for ordering and soldering these too? For example, 20-30% more than the mouser price is something common? More? Less?
3. Regarding taxes and import fees, is that something that applies when components enter china for assembly or when the boards exit (or enter my country/EU) for final delivery? Can those fees increase so much that assembly in the west will eventually be more worth it (better quality/speed-price ratio?)?
4. The directions on the elecrow site regarding the files they need are unclear. Do their inhouse engineers/project managers help with converting your eagle (or whatever) design to manufacturable format? Is it charged extra? Is that fee reasonable, in general?
5. Are there any costs that I can get away with when I reorder the exact same board? Like component sourcing fees or whatever?
I've never done this, so I'm quite lost here.
for your question, maybe i would be the one , to answer you...
1. as the silkscreen, it is indeed important for the soldering. but actually you can even do not add any screen on the board , for manually placing, which is normal for prototyping production, you can send a soldering guide files, to explain to the soldering man where the componnents is and the direction.
2. as the component price, actually it would be almost the same as digikey/mouser. for mass production, you will find the components price even lower than mouser/digikey, as shenzhen is the most important electronic market in Asia and then can get the components with lower price;
3. you do not need to concern the tax fee when components from US to China, what you will paid to vendor is just the quotation fee; when the package ship to you, some tax fee maybe needed in your local custom...depends on your local policy, but normally the vendor can declare the package value lower to avoid/reduce the tax fee;