We're going through this now as software engineers who are building EEG devices for sleep (https://soundmind.co)

We've taken as much software engineering methods as we can and applied it to hardware. So where many people are focusing on how you get your product manufactured, I think that is jumping ahead at this point.

Our process, and what we'd recommend to somebody else in our shoes is.

1) build your prototype with off the shelf components. Make it rough, make something that works, doesn't have to be polished and ready for production.

2) Show that product to your potential users, get them to use it. (hopefully you've been talking to users before this point, but it's nice to have something that is not complete vapourware). Learn from these prototypes, work on your software. Keep building hardware and iterating, and keep learning. Learn from them what they'd pay for the product, how much is it worth to them.

3) Do a back of the envelope quick math and see if you think you can make the product for less than they would pay for it. If not, maybe find another way to solve the problem. You don't need to be solid on your numbers, but you need to be able to ballpark and say "I think I can get this mass produced for $150, and can sell it for $180...hhhhmmm is that enough profit to make this a viable business??" You should be able to get help with this from some contacts who know about business if you're still uncomfortable, or show it to somebody who has done hardware and get their input.

4) When you think you've got things to a point where you are ready to get something to go to market, figure out if you can build it yourself (not mass manufacturing, can you build 1 or 5 or 15). If you don't have a vision for the aesthetic of what your product should look like, you can get industrial designers involved (we did), but from the vision point, see if you can build something yourself.

5) For hardware components, use as much as you can off the shelf. We're using esp32 which gave us the processing power we need, with ble AND a pre-certed antenna. We've designed our hardware such that our charging and power management is separate from our main PCB. This way we can get our power supply certed and (in theory) make changes to the main board with limited re-cert requirements. For batteries, see if you can use an existing battery pack. Camera batteries are available with protection circuit and plastic housing, which can save you on the cost of getting your own plastic molds for that component.

6) For us it was important to keep removing plastics and other molded components from our design. Mostly because we don't want to be creating more plastic waste, but also because molds can be expensive. See what other materials you can make.

7) At this point, you've got the BOM for hardware, you've got your enclosure or whatever you're packaging is. You should be able to get a bill of materials for these items. Getting PCBs built up is not that expensive, you can go to many sites and get quotes. Speak to local manufacturers about what is needed for your enclosures and get those priced out. Don't forget packaging, shipping, insurance, etc. I'm not sure of your product, so not sure what else you'd need, but at this point, you know enough that you're getting pretty close to knowing what your costs are.

7) Re-do your forecasting and now deep dive into your costs further. Maybe you can continue to strip down your costs (we've taken our BOM (bill of materials) down by almost 20% on our latest iteration. You've likely spent a lot of time up to now, but you're hopefully getting close, and you hopefully haven't spent much $$ but lots of time in refining the business and hopefully the product.

8) If all systems look good, and you still think this is a valuable product to bring to market, now you can begin talking to manufacturers. A manufacturing engineer might be able to help you to further refine the design to make it easier to manufacture. Local manufacturers likely have designers they like to work with who can help get everything ready to manufacture.

At this point, you can start following all of the advice around minimum order quantities, managing manufacturing, shipping, certs, etc etc.

As a software engineer, the one thing I'll tell you that I think we've learned is that software engineers work much faster than hardware, and people will say "hardware is hard", or "industrial design is slow". I thin all of that is BS. We contract with an EE who works at our speed. We do hardware iterations very quickly. It only takes a few days to get boards built up and sent from China (seems to really be the only place making up boards) and with early prototypes we were building (adding components, resistors, caps, etc) ourselves.

Getting a local manufacturer to build up your boards doesn't take long (from our experience) you just need to manage the pipeline as they need more lead time. But if you're managing the things you need to do, and keep them in the loop, you'll be organizing product, components, etc etc. So far, I've found the logistics management to be a big part of the challenge.

The biggest disappointment for us was industrial design. Our designers gave us an excellent direction in product vision, which we didn't have initially, but they were far too slow to work with. We were advised to bring industrial design in house and do it ourselves. I thought that was crazy advice, but I started doing it. At first really rough prototypes, and just kept refining ,refining, refining. I'd say I got 10x further than our ID group did in about 1/5th the time. The guys we hired are great at what they do, but the industry doesn't move at software engineering time scales. We're not slowing down waiting for people, we need these slow moving pieces to move up to our speed.

Having said that, we're in neurotech, so our software dev cycles are slower than your average software development, but still....

Lots of info there, and we're still in this journey ourselves. Hope that helps.