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Don't Push or Pull-POLCA
by Rajan SuriReprint from APICS-The Performance Advantage Volume 8, Issue 11
In the domain of material planning and control, a key concept in lean manufacturing is that of pull, implemented on the shop floor or with suppliers through the use of kanban. For years, JIT experts have pointed out drawbacks of the traditional push approach implemented through MRP systems. Pull and kanban have been touted as the solution to the problems with push and MRP.
I will show that in some markets, pull is not the answer either. Instead, we need to go beyond the limitations of both push and pull. For such markets, a new material-control approach call POLCA can give us the best features of push and pull systems without their drawbacks.
To see the need for a new material-control approach, we should understand where the QRM strategy is most effective. QRM focuses on creating short lead times throughout the organization, and it works best for 1) companies that make highly engineered products in small batches, even one-of-a-kind; and 2) companies that do not engineer each product, but have a large number of different product specifications with highly variable demand for each. We will refer to such a company as a "QRM company."
For a QRM company, we'll see that kanban, rather than minimizing inventory, will lead to a proliferation of inventory. Worse, in some cases for a QRM company, a pull system fails altogether. To understand why this might be the case, let's review some concepts of lean manufacturing ...
