Without knowing exactly what you are working on, here are a few ideas:
1. Figure out if you can do fewer slow iterations. What's driving the need for a full PCBA run for each iteration? Might be able to split out to rigid assembly and flex for example.
2. Run more experiments in parallel. If you have multiple ideas or variations to test, design them all and fabricate them all. Flex antenna? Make like 30 parametric variations.
If design then becomes the bottleneck, then automate that next.
This is exactly what prototype PCB manufacturers are for. If you're in the Bay area, SF Circuits (and a dozen others) will give you 24h/48h turnaround times. This is a highly commoditized service. Even the generic manufacturers like PCBway have options you can purchase for faster turnaround if you meet the constraints.
Don't move to Shenzhen. You don't have the social connections for that and it'd just give you a bunch of new problems.
There are many good common sense answers in this thread: parallelize the runs, use faster (but more expensive) local runs, have a better model (physical or digital) to reduce the runs.
To answer your specific question, Shenzhen is a good place to work on hardware, but it is not like you just fly in, and people start building for you. Your own lead time (establishing yourself there) will likely be in weeks if not months. This is from my personal experience in Shenzhen and other hardware founders'.
If you want to build the prototype faster, identifying the bottleneck is a great start. Which takes most time? For up to medium complexity, PCB fab (the board itself) is the most time-consuming part. Anything more complex, it could be the SMT assembly. Each part of the entire process can be optimized: PCB fab can be done in-house quick (chemical etching, CNC machining, etc). Assembly can be optimized too (solder reflow oven, solder paste stencils, etc) on a small scale. I would estimate a batch of 5 boards of 50 SMT components each can be produced under 8 active engineer-hours. That's your entire prototype in a work day.
Do you have professional/academic training in electrical engineering? EE is no less complex than CS, and perhaps studying up the entire process will help you identify what's possible and what's the bottleneck.
Don't assemble via JLC. Get a good soldering iron, skillet, sand, paste, and order from mouser to do them yourself. If you're iterating errata with a full run each time you are wasting unbelievable amounts of both time and money, and you're probably not tinkering with the board enough, increasing your overall iteration count.
You’re confounding lead times on assembly services with iteration time.
If you’re bootstrapping, find a good quick turn board house and assemble the boards yourself. Get an lga-12 stencil and hot air tools, maybe a benchtop reflow oven.
> Strongly considering moving to Shenzen to build the prototype.
That seems like a profoundly personal decision that would have more ramifications than you expect.
Breadboarding should be possible, same with soldering together prototype PCBs as long as you're not concerned with wearing the prototype yourself. There's also (albeit expensive) circuit modelling/validation software you could try to use. I don't think many circuit designers have a workflow where they perpetually buy finished prototypes to check if they're working or not, though.
Fiber laser. Even a 20W fiber laser will ablate copper. 30W-50W are now avaiable for under $2k, maybe even dropping still.
You'll be limited to single or double sided, without vias but considering its rapid prototyping, these are the compromises to be had.
You could always try CNCing prototypes but this is fraught with trouble. Fiber lasers offer the simplicity, repeatability and speed that normal laser cuters, but with metal.
Add why to a checklist each time you fuck up. Then validate the fuck ups aren’t happening next time.
I usually get boards right first time now. But it took me 2 years to get there.
> I'm building wearable tech, and the JLCPCB lead times are my biggest bottleneck for iteration. 3-4 weeks is way too long.
Hm... my experience with JLCPCB is that I get 7-10 days iterations from sending my gerbers to getting my boards in SF Bay Area. Still long, but much shorter than your experience.
Is it shipping, PCB manufacturing or PCB assembly that takes so much time?
Where are you located? 3-4 weeks seems very slow for JLCPCB. Are you shipping to South America or something?
If you can afford the time, effort, and expense needed to move to China, maybe you should look into working with a local board shop that could provide more rapid turnaround.
The best way to improve your development time is by doing fewer iterations. Often easier said than done, but you should be designing for test and rework and thoroughly reviewing your designs before submission. You said you're making flex PCBs -- have you considered doing fast-turnaround prototypes on rigid PCB to make sure your electrical design is good? What kind of problems are you having that are forcing you to do extra prototyping runs?
Is there no local PCB manufacturer near you? Normally, local manufacturers can do that sort of thing for about $2K or so with quick turnaround (<1 week). Assembly is normally anywhere from 1K to 5K extra depending upon complexity.
You should be able to buy quite a few local turns for the price it would cost for you to spend time in Shenzhen.
Unless you're Chinese is very good or you have a trusted local contact, you're not likely to benefit much from heading to Shenzhen in person.
We are using JLC for PCB + PCBA and usually the boards are ready and assembled between 5-6 days and then takes 3-4 days to get them shipped to europe.
Can you find a way to reduce the iteration itself? I've never done wearables, but last time I did a product there was almost zero iteration. There were updated versions with easier DFM, but nothing like the iterative process I'm used to with software.
I feel like something might be slightly wrong here. Are you iterating because you haven't finalized the core innovative tech? Can you develop that first, on breadboards or with lab bench equipment?
Are you iterating because of minor aesthetic tweaks? Can you just make one PCB with LEDs in all the places you might want them, turn off the unneeded ones in software, then leave them out of the final BOM?
Are there just straight up mistakes, that could be fixed with slower iteration?
Maybe it's just that I've never quite made it to the level of career success where there's a budget and time for this kind of iteration, but I still think something could improve.
You haven't given us enough information to make a recommendation.
Why are the lead times so long? Is it the shipping? If you're worried about operating in China another option would be to move closer the shenzhen. Kuala Lumpur has cheap rent, good infrastructure and overnight shipping to shenzhen should be possible. Similarly Korea, Vietnam, Taiwan,Singapore and so on are easier to operate in while being closer to the "source". Definetly go and visit Shanzhen first though.
What kind of board specs do you typically deal with? This can have a significant effect on leadtime and who you ultimately decide to deal with.
If you just need a lot of unique double-sided boards to play around with in "alpha" and you can wait longer for the "beta" boards from your supplier, you can use several different small scale processes to accomplish that, such as photoresist, milling or printing.
Pay for DHL Express shipping when ordering from JLCPCB.
A lot of folks are missing OP's point about making wearable tech. Flex in the US is just not fast or affordable. There's no reason for it to be (from the fabricator's standpoint).
OTOH, most of the stuff can be and should be prototyped on standard rigid boards.
For standard 2L rigid boards:
If you work in 1-week cycles, you can usually send a PCB out on Thursday or Friday and have it in your hand on Monday or Tuesday to assemble and test. About $40-$100 per round.
If that's not fast enough, a domestic fab shop that can do 1 day turn on bare boards for not terrible pricing - about $150-$200 per round (unless you can will-call at the dock). 2 or 3 day with soldermask/silkscreen will probably be around $300-$500 per round.
Prices are rough estimates off the top of my memory from the shops I've used.
JLC is 10 days order to arrival, for US east coast, with assembly. 8 days without. You're using DHL, right?
PCBway does 1-2 weeks to Europe, US should be similar? EuroCircuits in Netherlands will do 4-5 working day to Europe.
Yeah, definitely don't rely on them for assembly. For prototype runs of a couple to tens of units, just do it yourself. Hire an intern for assembly and just order bare boards. Standard lead time for boards is on the order of a week, if not 24h.
The equipment isn't expensive and you don't need much labor. I bet a 2-3 week wait costs you a lot more than a part time assembly tech.
side question: is there a LLM that can create PCBs from text?
Most of the comments strongly advise against moving to Shenzhen.
Having prototyped in both places I’ll make some arguments for. I’ll preface it’s only worth it if you’re beyond the limits of what American facilities can do and it's a step function in workflow and getting setup. There is an acceptable cultural tunnel vision in our field that developed in the 1980s for "how to do things" and hasn't changed much beyond "4 layer pcb on FR4 with surface mount components" - going against that grain requires an interdisciplinary mindset - as in "make a functioning circuit on a piece of toast" level of creativity[1].
If you’re building wearable tech there’s a strong chance you’ll need to make flex pcbs sooner or later. Those are comically cheap in China and stupid expensive stateside.
Especially when you start pushing the boundaries - there’s so much low hanging fruit for experimenting with your PCBs when you’re in the factory making them. Most US manufacturers will only let you use one color for a solder mask. In Shenzhen we pioneered using full RGB to print any graphic on your pcb back in 2017. Even on top of the chips themselves. It’s now pretty easy to source. This is literally just by being on the factory floor and saying “hey can you do step 5 before you do step 4? - we want to take the boards to this other factory across town first” And they say “sure”. Likewise if you want to mount your parts sideways or upside down to save space. Or say, take a literal sea shell through a copper PVD machine and mill away some traces and mount some chips. They do not care and will gladly take your money and make it happen.
One time we couldn’t find a single vendor in the US or Europe who would embed chips in the middle of pcb layers[2]. This was a weekend project for one of our Chinese vendors - who also had never done this but it sounded like fun so she said “no problem”.
Can get turnaround on prototype boards with assembly for free once you have a cm or just $50 if you don’t. One American vendor comically insisted one couldn’t mix flex and rigid boards for one of our designs for less than $10k. In China it cost me $80. Likewise we mounted chips to non-traditional media like credit cards with no sweat.
Any chip we wanted was available through HQB or TaoBao when Digikey was still backed up on Covid.
Test fixtures (the laser cut jigs that you program and test pcbs) are $100. Stateside they were half as useful and $2000.
You’re one blue Buick minivan ride from Guanzhou where all the garments in the world are made. Being at the intersection of these two cities is a strategic advantage.
Cost of living is cheap.
It will make you a better engineer by exposing you to the dirty business of manufacturing first hand. I'll go so bombastically hyperbolic and say not moving to Shenzhen as an EE is like not moving to Nashville as an aspiring country musician.
In China the saying goes “anything is possible, nothing is easy.” I’d mostly agree with this but also point out that price is completely-orthogonal-to-possible in China, absolutely not in the US, and straight up forbidden in Germany.
[1] https://talk.dallasmakerspace.org/t/breadboard-electronics/1...
[2] https://twitter.com/pmg/status/1248148053795540992/photo/1
p.s. If you enjoyed this comment, you may also enjoy my "So you want to start a factory?" reply on a post from a few days ago [3]
[3] https://news.ycombinator.com/item?id=40001222