Product Design Case Study: Innovative Furniture Production Prototypes
Production prototypes - the icing on the cake before mass manufacture 
If the customer is satisfied with all the CAD models and rapid prototypes, then production prototypes are required to proove out all manufacturing methodologies and the final CAD design. Everything should come together as designed! The production prototypes are also 'good enough' to start selling to perspective customers, giving the customer an opportunity to recoup cost of investment and proove market viability of the product. Of course, design changes may be required to better or refine the design, change the function (but only slightly), increase the performance or lower the cost of manufacture. If performance is as required, then we move to manufacture.