TIA
If I have significant investment capital or lined up buyers on a high-margin product, I'd look for a US supplier on ThomasNet, at least to start, once you go through the small-run back and forth you can look to moving manufacturing overseas. I've had poor experiences with the "Alibaba Method" (finding a Alibaba seller w/ a similar product and then trying to get yours made or white label their existing product). Often times the sellers on Alibaba aren't the actual manufacturers.
For Electronics: Go right to China. https://www.pcbway.com/ is a great company for rapid, small-run prototypes. They are also reasonable at volume.
Injection-moulding, Extrusions: You often won't save significantly by looking overseas. Find a U.S supplier to start. Prototype with small-batch methods (3d printing, laser, milling).
My experience is from North America manufacturing in China.
1. You get what you pay for. If you don’t want to pay for quality, don’t expect quality. If you squeeze the manufacturer, they will cut corners.
2. I only have experience with low cost Chinese manufacturing, so this applies to that. - You need to get the entire process proved out and dialed in before sending overseas. In my experience, they were either not able (or we weren’t paying enough) to go from drawing + 3D model to a fully operational production process. We had to make all tooling and checking fixtures and ship them overseas for production. - get first part inspection documents. Receive those exact parts and repeat that first part inspection on your side - you need to specify inspection plans, which should include at a minimum: what to check, how to check, with what measuring device, inspection frequency - if you require specific machining or processes, that needs to be specified. Don’t leave it open to the manufacturer - you need to get good documentation from them and make sure they aren’t dependent on one person... after one lunar new year we received new parts that weren’t up to specification. It turns out the one person who knew what paint to use didn’t return from vacation - I would specify some sort of acceptance sampling plan to either accept or reject the entire lot
3. If your product needs to adhere to some quality standard (e.g., ISO, IATF, etc.), make sure they have the certificates and can prove documentation.
4. Don’t be surprised if your product ends up on eBay or some other site. If you’ve heavily invested in development and it’s novel, consider getting it manufactured locally where you can maintain a direct relationship.
5. Have someone that speaks that language fluently and knows the local culture and customs working with you.
6. If you don’t have manufacturing or quality experience, find someone that does
1) make sure the manufacturer you are talking to is already manufacturing comparable products - efforts to make them manufacture a type of product they are not already familiar with are likely to fail;
2) make sure the manufacturer you are talking to is already manufacturing at a level of quality that is in line with the quality you want - efforts to make them manufacture at a higher level of quality than the manufacturer is accustomed to are likely to fail;
3) familiarize yourself with regulations for the manufacturing, import/export, and sale of the product you want to develop before you talk to the manufacturer - regulations will always eventually catch-up with you and you risk wasting effort, money and time not covering them in advance.
Many of the points are still valid even if you are not manufacturing in China.
1) This first piece is by Richard Lazazzera of A Better Lemonade Stand. I think he actually works/always worked for Shopify. No big issues there...they appear to be using a content-first growth strategy.
https://www.abetterlemonadestand.com/the-ultimate-guide-to-s...
2) This is a link to Sourcify.com. They help people navigate Alibaba and the entire process. I haven't used them yet, but I hope to in future.
HTH
Beyond that it really depends on what you're manufacturing, and what you can spend. Look into PPAP (Product Part Approval Process) and take ideas from there. It is the process automotive manufacturers follow and will soon become an aerospace standard.