One Person’s Experience Of Having PCB Assembly Done In China

Those of us who have our PCBs manufactured by Chinese PCB fab houses will be used to seeing tempting offers to also assemble our completed boards. Send the Gerbers as normal, but also send a BoM, and for an extra slice of cash you can receive fully assembled PCBs instead of just bare boards. It sounds alluring, but leaves a few questions for those without the experience. How much will it cost, what will the quality be like, and will my boards work? [Alexander Lang] had a limited run of ten small pressure sensor boards to make, and since his board house had started an assembly service,  decided to take the plunge and opt for full assembly.

His first step was to assemble his BoM and send it with the Gerbers. He is at pains to stress that the BoM is key to the whole project, and getting it right with the correct packages and more than one source for each component is critical. The board house first charged him £32.05 ($41.76) to make his PCBs and stencil, and assess his BoM for a build quote. A few days passed, and then he had a quote for assembly, £61.41 ($80). He placed the order, the board house processed it and made the boards, and in due course his working PCB modules arrived.

This might sound at this point like an unexciting saga, but its very smoothness is the key to what makes it interesting. Those of us who have wondered about the risks involved in taking up such a service need to hear stories like this one as surely as we do stories of failure, because without them we’re flying blind. Whether £93.46 ($121.76) for ten small boards represents good enough value is another matter, but if surface-mount soldering is not your thing you might be interested to follow [Alexander]’s example. After all, it wasn’t so long ago that getting a cheap PCB made in China was a similar leap of faith.

41 thoughts on “One Person’s Experience Of Having PCB Assembly Done In China

  1. This seems like it was a success mostly because of the very low part count.

    Our experience has consistently been a headache. Almost all the hassle is in getting them to source the right part. When there were mistakes we ran into timezone and significant language barriers. We ended up having to just buy the parts ourselves and ship them separately.

    Maybe our bad experiences are unique. My intent is not to say that our problems are typical. I think that the board above is far too simple to expose the potential problems.

    1. I must admit I did make sure the first circuit I did this for was as simple as possible and only used very easily available parts. I didn’t have any issues with language however I did use google translate and sent my instructions in both English and Chinese characters. As with anything like this try to make things as simple as possible and everything hopefully will be fine. If certain parts are more esoteric provide a local source for the parts…

    2. This is kind of a big concern for me as well. Just about everything that I get made in any sort of volume has at least one, perhaps two parts that I would definitely not want substituted willy-nilly. In the case of my most recent small-batch-build, one of the parts is a SkyTraq GPS module that I’d kinda be surprised would likely be legitimately available other than importing them from SkyTraq (and they’re in Taiwan – that can’t be an easy import/export relationship).

  2. As above, the most hassle we’ve had is when the assembly house have to source parts they don’t generally keep in stock (and here a list of what they have it invaluable and likely worth changing your design if necessary to use stock parts). Unusual parts tend to cost more than I can source them for here (UK) and more than once we have had counterfeits despite being from “legitimate sources”, which I’ve only managed to prove and claim back for because I have a friend who works in the XRay industry….

    But I would agree it’s well worth a look, especially if you have low part count boards.

    1. I agree and would like to add that importing electronic components into China is a hassle in terms of paperwork for the assembly company and additional import taxes that are charged. In addition, many companies may actually have a limit on how much they can import.

      One thing to keep in mind is that people need to specifically stress what components cannot be substituted. Often if a component has no note saying that it cannot be substituted then it is taken as fulfill with whatever is available.

      1. I agree entirely and my bill of materials made this very explicit…however this design was deliberately simple. I had a good experience. It may have been lucky…I have ordered another batch – lets see how this one goes.

  3. I’ve been using Fusion PCB which is Seeed Studio’s offering and even with a few medium complexity boards have havent had any issues. That could be due to the fact that they produce some fairly complex boards for their own products but either way they’ve gotten things right for me.

  4. Wow…seriously? How the heck do you think probably 80%+ of all PCBA’s are made? Exactly in this manner , and in China. Getting a good assembly service is hardly a stretch worth mentioning. There are far greater successes than failures. In the hobby world, the failures are almost entirely the fault of the person putting together the documentation. I mean, you bring this up as if getting a good PCBA is a rarity. Quite the contrary.

    1. If the majority of problems are caused by the person putting together the documentation, then that’s still a problem. It speaks to the need of a guide to follow to generate foolproof documentation for the PCBA.

      It’s still a problem to get good assembled PCBs from China because *we* do not know what we need to do to make it a success.

    2. It’s a question of experience and effort. 80% of the worlds PCBs made in China are done through large and experienced channels and through iterations that eventually resolve part sourcing and manufacturing issues. On the other hand the success rate for single small runs is not something to write home about … unless you’re writing mostly using expletives.

      1. Yes. This. Absolutely, this is Not A Hack. But read the article again, expecially the bit where I am at pains to make that point. For a lot of our readers this is unknown territory, hence drawing their attention to someone’s success story.

    1. The circuit is already shared with everyone anyway…nothing special or proprietary there – purposely so. If people want to copy it they are free to do so – I’d be flattered if it was copied – means it was good enough!

      1. Yup, but if your “prototype” design (open or not) that you had contract-built in China is DANGEROUS or BAD in some way, there will be cheap Chinese copies of the flawed device available on EBAY – forever!

        1. Thankfully my design is neither of those things :)

          It is something to consider for certain. Personally I would not get a prototype completely turnkey manufactured…If possible I breadboard first or get just the pcb made and populate and test it myself. Once I’m happy the circuit works to my satisfaction then I might consider getting it turnkey manufactured and then only if I need multiple units. It isn’t worth doing for one offs in my opinion.

        2. > Yup, but if your “prototype” design (open or not) that you had contract-built in China is DANGEROUS or BAD in some way, there will be cheap Chinese copies of the flawed device available on EBAY – forever!

          So don’t put your company/product name on the prototype. Then when it works, you can say “this one works, not like that shit on ebay!”

  5. Thanks very for recommend Elecrow to Hackaday hobbyist. Elecrow can provide turnkey solutions for makers include PCB fabrication, components sourcing, PCB assembly, testing and shipping and there are several project managers to give quotation for PCB assembly and follow customers’ projects status. Please feel free to contact us if there is any we can help or cooperate with us. Make your making easier. –David From Elecrow

  6. I’m a freelance electronics design engineer who lives in China and I’ll tell some of my experiences.

    Getting PCBA’s done in China is just a hassle. And this is for simple boards to full featured tablet boards with quadcore cpu, ddr3 etc.

    I have dealt with low end to high end assemblers and there always is an issue.
    1. Them ordering the wrong part (even trough the full part number and vendor is specified; And told not to deviate from that)
    2. Them switching out parts so they can be off cheaper / do less work (even if you deliver all the parts to them)
    3. Reasonable quality PCBA assembler is also expensive here; for that price you might as well go to eastern europe or something like that. And have no hassle at all. Low end pcba assembly in china is around 200-300 usd (if you count the margin that they make on the pcb,stencil and shipping) to 400-700 usd for a medium quality pcba assembler.
    This is based on qty 10 for a board with lets say 50 passives and 5 ic’s (no bga just qfn etc).
    4. Them not delivering the assembly quality that is needed. Explicitly asked if they can do the board etc, not do hand assembly but use their expensive pnp etc. for some bga parts. Result … shorts everywhere, a lot of bs with the fab. Eventually after 1-2 months it was fixed with a very low yield. I paid half of the bill and never worked with them again.
    5. They want a lot of random documentation / talking about things that are not needed to assemble the board. This takes a lot of time and makes the process expensive.
    6. When they switch out some parts and you are fault seeking why the boards that you built yourself work but the one’s from the fab do not because they switched out some part for a fake / non compatible one. And you spend hours tracking this down and fixing it. Can double the assembly price quickly.

    All my clients have the same experience, they deal with china frequently.
    These days I just assembly prototypes in house with my pick and place. It works out to be the same price or even cheaper. With less risk, faster turnaround.

    NOTE: The pcba fabs switching out caps or resistors (even if you specified it / send them the parts) is really common. The (expensive) caps that you send them just go on to the gray part market to make some more money. And you might get sub-standard caps back which may or may not be an issue for dcdc’s or higher voltage circuits due to DC bias of the cap etc…

    1. Do you have micros on the boards you send over there? EEPROMS or PLCs? Do you have them programmed there, or do you program them all yourself? I’m assuming the runs you are doing are less than 100 boards or so? Do you buy them programmed?

  7. I’ve used Elecrow for PCB’s and was recently surprised when they emailed to ask if I wanted a slot in the PCB plated as this wasn’t clear in the gerbers. I expected them to just fab it without checking with me. I was quite happy about this.

    Sadly I’ve had problems with contract manufacturers in the US and China despite going to lengths to avoid any ambiguity. Good contract manufacturers typically own up to their mistakes and provide free rework but it doesn’t help your deadlines. US contract manufacturers typically take quite a while to quote (with the exception of a few automated services), while china usually gets you a quote in 48 hours, however you run the risks of part substitution.

  8. I’ve had good luck with PCB manufacture itself, but, designing mostly high-end audio systems, never in a million years would I let them assemble the circuits for me, not even if I sent them the parts, that goes for any critical circuits as well. I assemble everything by hand to make sure that everything is perfect and reliable. The assembly techniques can be an extremely important factor of a circuit.

  9. The Elecrow service is just assembly of the boards, with no (functional) testing. What I read in their product description is they handplace and handsolder all the components. Visiting a couple of factories in china I see here bored smoking kids handsolder components. For this price I would solder them myself (and learn to solder SMD for the author) as indept knowledge of the circuit helps a lot with assembly.

    No electrical testing is IMHO a big no-no here, and I don’t know if the author can repair them.

    1. Thank you for your comment – I’m the author of the post and I can solder surface mount components perfectly well and I can fault find and repair my own designs perfectly well; It just isn’t an effective use of my time. The soldering performed by Elecrow was excellent in my opinion, I can’t comment as to the age or attitude of Elecrow’s assembly technician but the results speak for themselves. I provided very clear instruction on how to assemble the boards as I’ve made over fifty of them myself by hand….that information proved invaluable to the gentlemen assembling the boards and Elecrow thanked me for it.

      I tested every unit that arrived from Elecrow and found them all to work perfectly and I will continue to test each and every board I have made. If I were to have a more complex PCB manufactured I would request electrical board testing after fabrication which Elecrow can and do provide as a service. I may not always get the entire circuit manufactured by Elecrow as I prefer not to start a production run until I have confidence in the circuits function, the ease of manufacturing and sourcing of parts – that’s the true skill in engineering. I also don’t necessarily always intend to use fabrication houses in China. There are more local fabrication houses but they struggle to be competitive on costs.

        1. No Problem – I’m capable of doing production but it is much quicker and easier when you have access to a pick and place machine and a reflow soldering oven. I have the oven but not a pick and place machine and for the amount of production I do it would not be worth buying one. Setting the machine up for a short run, again isn’t worth my time in my opinion. Far better to have someone else do the production work so I can get on with the design and testing – again my opinion, other people’s opinion may be different ;)

  10. I have a question – I’m thinking of taking 6-7 sample sets of my PCBA to China with me on a flight. Do you think the customs will allow me to take them and how much I can take with myself.

    1. Well…I have never had an issue taking circuits on planes. As long as there are no undeclared lithium batteries and the samples are well secured in packaging and not powered up I don’t see why there would be an issue. It is no different from taking a finished piece of electronic equipment on an aircraft.

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