by Susan Pleasant
I am surprised by number of times I find lean tools, concepts and principles misunderstood in organizations that are several years into their lean journey. A few weeks ago Jamie reinforced the difference between takt time and cycle time. It is not unusual to hear a lean leader refer to takt time when actually describing the cycle time of the process. Mixing those two up is a little like smiling with lettuce on your teeth after lunch – no one will tell you about it but everyone that notices is just a little embarrassed for you.
I find a similar misunderstanding and misuse of “supermarkets.” I go into operations that will show me their “supermarkets.” As I inquire a little more what I find is their definition of supermarket is a complete set of parts and materials staged closer to the line than the warehouse. At best, that is actually a FIFO materials storage rack.
A true supermarket is storage characterized by high use materials (A items) that turn faster than the standard material handling cycle located close to the line to facilitate retrieval by an operator or water spider/utility. Supermarket replenishment is triggered by kanban cards, min/max designation, electronic signal, lights, or routine “milk runs” by material handling.
The objective of the supermarket is to reduce material handling time and transportation waste. It should be easy to assess inventory status using visual methods rather than having to count parts. If possible the best case is to keep the operator focused on value added tasks rather than retrieving replenishment parts.
Good luck with your materials flow plans.