[quasse]

Do you have in-house SMD assembly experience? When I was doing fast turnaround prototyping, being able to build up the boards in house was invaluable.

Do you need your prototypes to be on flex PCBs? If you can get the electronics ironed out on FR4 you're going to save a lot of time and money on prototype revisions.

If you're waiting for JLCPCB to assemble all your boards for you you're slowing your process way down. Pay for 2-3 day processing at PCBWay and then assemble in-house. If you can prototype on FR4, PCBWay can literally manufacture the boards overnight and DHL them to you before noon the next day.

[RohKo]

Great idea! I've never soldered SMDs but can defo learn. We're getting are boards assembled rn because soldering LGA-12 package ICs by hand is unfeasible, and it seems pointless to pay the setup fee and not get the other components done as well. Does that change your answer at all?

[dboreham]

Not trying to be rude, but someone who is complaining about PCB turnaround time, but has also never soldered SMDs sounds odd. You need someone who knows what they're doing on staff. Either hire that person or become that person.

It's been a couple decades since I was involved in the H/W business, but there are usually tricks you can use to assemble even very fine pin-pitch devices in your kitchen. Heat gun, microscope, etc. I'm guessing there are 100 YouTube videos on this. Assemblers will tell you it needs ZYX special machine that only they have, but actually you can do it yourself, albeit slowly and with defects here and there.

Back when, there were decent PCB houses in the UK (up in the midlands typically, not near London). Perhaps they're all out of business now but you might go looking for one of them vs back and forth to Asia for prototypes.

Edit: a quick search suggests that there are many UK manufacturers still alive. E.g. [Forward, Newberry, Leicester, Stevenage]circuits.

[MobiusHorizons]

Can't plus one this enough. These skills are very achievable, and IMO are required for successfully building prototypes. Especially if you want to be able to salvage an experiment where a couple of mistakes were made, you may need to cut traces solder a few wires and possibly bodge some components on in order to validate the design before ordering the next iteration.

[jon-wood]

LGA-12 is totally doable yourself, make sure you get solder stencils with the boards and buy yourself a cheap reflow oven. Then you just put solder paste on the board using the stencil so it's in the right places, place the components, and the oven melts everything into place.

[floxy]

Buy yourself some laser-cut paste-mask stencils out of Mylar (https://www.pololu.com/product/446/). Get the room-temperature stable solder paste from Chip Quick (https://www.chipquik.com/store/index.php?cPath=470&osCsid=il...). Buy a cheap temperature controlled hot plate (https://www.amazon.com/Soiiw-Microcomputer-Soldering-Preheat...). Get some cheater glasses with 3x or greater magnification, and some good tweezers. Place parts by hand, and solder them within minutes on the hot plate. Maybe watch a Youtube video or two. Easier than it seems. I've done LGA-12 with a setup like the above (a ST LIS2D12 3-axis accelerometer). Also, goes without saying that you should get a soldering iron with a fine tip for large part rework, and possibly a hot air pencil for reworking the tinier parts.

For the parts with pins you can't reach with a probe, be sure to leave a way to test connectivity of the pins with a DMM. For the super tiny parts with the hidden pads, I like to have a series resistor that I can remove, and then use a DMM to check that you can find the ESD diodes on each pin of the package.

[eyegor]

Lga12 with soldermask stencils and a hotplate doesn't work? Should be doable for prototype quality. Might want a computer controlled pick and place with a suction arm/microscope but it's definitely feasible. Look up some of the gpu repair guys for inspiration, they often do some insane bga parts (nand chips) by hand.

[gchadwick]

Getting the tools and skills to do PCB assembly and SMD rework seems like a no-brainer (indeed I'd say essential!) if you're aiming to do serious work with building hardware. Not something I've done myself but soldering an LGA-12 doesn't look too hard with appropriate tools.