William Manufacturing Company began implementing a just-in-time inventory system several months ago. The production and purchasing managers, however, have not seen any dramatic improvements in throughput. They have decided that the problems are related to their suppliers. The company's three suppliers seem to sendthe wrong materials at the wrong times. Prepare a discussion of the problems that might exist in this situation. Be certain to address the following items: internal and external communication; possible engineering changes and their impacts; number, quality and location of suppliers; and length of system implementation.