Design for Manufacture (DFM): The traditional approach of product design involved breaking the project down into a series of steps that were executed sequentially. These steps were assigned to different departments which, for the most part, worked independently. The benefit was enhanced specialization and functional job focus of product development. The drawbacks were increased overall development time and difficulty in integrating manufacturing activities.
Designing for Manufacture (DFM) is the practice of designing products with manufacturing in mind. The goal is to reduce costs while maintaining quality and reliability, as well as decrease the amount of time it takes to get the product to market. To achieve this, the product must be designed so that it can be made simply.
By the time a product has been designed only around 8% of the net product budget has been spent. But by that point, the design has determined 80% of the lifetime cost of the product. The design determines the manufacturability, and that determines a significant part of the introduction and production cost - the 80% of the product. Once this cost is locked in, it is very hard for manufacturing to remove it.