Flow rate flexibility in complex production departments

Consider a production situation where it is desirable that the production orders of different product types have different flow rates, independent of their production characteristics such as processing times. Flow rates are mainly determined by the work centre waiting times, thus the product types should have different production order waiting times at the work centres. In this paper the authors derive a method which makes this possible in a controlled way: given certain values for some parameters the different waiting times (and thus the flow rates) are predictable. By means of simulation this method has been tested for a production situation where only two different flow rates are required per work centre. This simulation study shows that, using a simple balance equation and operation due-date sequencing, it is possible to create different predictable flow rates. It turns out that until a required waiting time reduction for one of the (categories of) products of about 60% has been achieved a one-to-one relation exists between the scheduled (required) waiting time reduction and the here-called normalized waiting time reduction.