Now that you have a prototype board, you must assemble it or contract with an assembly house to do so. During your career, you should endeavor to send out at least one prototype board to a fab and have a contract manufacturer build it.
Assembly of your product can be a significant factor, especially if you have a complex product. The best way to get this information is to work directly with a CM so that they can understand what needs to be done. Keep in mind that it is not just putting parts together, but also testing your final product, packing it up, and all the other logistics of running a factory that go into labor costs.
The minimum wage in Shenzhen is roughly $2.50/hour, but keep in mind that your line will have multiple workers, as well as supervisors who will be making more per hour.
You can either estimate how long it will take in man-hours to manufacture your product and multiply by the wage above, or you can use a simple multiplier of your total BOM cost to estimate. 10% of your BOM cost will get you into the ballpark.
The experience you gain will help you understand the vicissitudes and exigencies of manufacturing. The fab houses are ready to help, even if you drew your design on a cocktail napkin, and you will be able to lower design costs because you have an understanding of the manufacturing process.
“Having a good board shop is part of your being an innovative company,” Even if you have four months to make a prototype, it is well worth it to have a fab house provide a three-day turnaround on your boards. In that way, your marketing and sales organization will have time to review the product and perhaps get one of your prototypes into the hands of a customer. You will then have the opportunity to make improvements and produce a better version of that board in less than a week. You can have a solid design after your prototypes comes out, remember, always moving to lower cost and fast delivery in electronics market.