Calculation of Tool Number
Flexible Manufacturing Systems that is abbreviated as FMSs are frequently viewed as system able of processing a broad variety of parts in random order. This is attained by determining by the number of tools of each type that are active in the system at similar time. Very few tools can result in low system use and throughput. Several tools in the system though can increase system cost. Proper tool management makes sure that the correct tools are used on the suitable machines at the right time that is why the desire quantities of work pieces are manufactured. The uses of tools and machines and throughput of each part type are significant performance measures that must be managed for efficient production.
The Numerical Control that is abbreviated as NC machines used in FMSs are very expensive to purchase, operate and keep and under-utilization of the machines can be very costly. Part throughput ascertains the revenue generated by the system. The number of tools of every type active in the system can enhance the machine utilization and system throughput. The costs related with lost machine time and failure to meet production quotas will decrease because of unavailability of tools. But the tooling needed by the NC machine is costly. To carry more tools than essential can increase the cost of operation and maintaining the system and complicate tool storage and transportation. Therefore, the number of tool of each type active in the system must be determined to balance these cost.
The tooling cost per unit time can be illustrated as:
Where, PT = Cost of idle tools,
PTi = Cost of idle tool of type i,
Ni = Number of tool of type i in the system, and
φi = utilization of tool type i.