This is a really difficult question to answer as every new product launch project is different, however, we'll try to give you some ballpark figures.
Engineering design: 15 days to 6 months
Accelerated life testing on prototypes and iterations until a final approved prototype: 1 to 3 months
Tooling fabrication: often around 6 weeks
Pre-production preparation, including pilot run(s): 1 to 3 months
Mass production (first batch): 1 to 3 months
Note: we typically help clients after the industrial design has been completed.