Usually this designer is part of an engineering group, either from an independent Product Design Services company, or an internal engineering group within a business. Typically, such groups have 3D printing access to test fit and function prior to moving toward having a mold built, usually the largest expense.
The quantity is often an unknown, depending on the future success of the product, however the choice comes down to a smaller outlay for a 1 or 2 cavity mold if the future requirement is unknown. If the product becomes a great success, it can always be re-tooled with more cavities, the math always works out if an unknown becomes tens of thousands per month.
Shadow’s Ridge generally has our Chinese associates do our mold tooling. Gone are the days when Chinese molds were substandard. If we anticipate the mold will be moved here, we have it quoted for US production, which increases the cost modestly, but the molds are made more closely matched to US molding operations.
When the mold is built, it is tested in China and samples submitted. We generally ask our customers to have some production done in China. There advantages of this are that any “new mold” issues are discovered and corrected by the original mold builders. Also, the customer occasionally discovers important needed design changes which are economically implemented by the original mold builders, occasionally a small design change can make a big difference in assembly ease or product quality. Finally, enough product can be molded in China ahead of the mold being shipped, which takes 2 months but 3 months needs to be allowed in the logistics plan for the occasional customs or land transportation delays.