This four-part Information Paper discusses the key aspects of MMC. Part 4 focuses on the issues surrounding the development and manufacture of MMC products. It discusses how to avoid 'muda' (any activity that consumes resources but creates no value), 'muri' (overburdening, eg insufficient time to carry out a function which has knock-on effects on the rest of the process) and 'mura' (unevenness, eg products are batched together), and considers the issues involved in buying machinery and business systems, and in reviewing the supply chain and staffing.