Polyhedrika

Learn by doing , although it takes longer, it is usually worth it. The Socratic method helps students find solutions for themselves rather than just being told. Group exercises and simulations are practical ways to implement this methodology. In most value streams the delay between actions and effects is long (sometimes months) so it is difficult to associate results to some action we took in the past. Simulation reduces this delay from months to minutes so this allows us to try different solutions and experience the results and any side effects our actions may produce. These are some successful group exercises and simulators: The Beer Game This is a group exercise which has been described by Peter Senge in The Fifth Discipline   It is very popular in management courses and it is a good example of learning by doing . It simulates a beer supply chain from the factory to the final customer.  The objective is to meet the customer demand for a number of weeks keeping the minimum ...

     Statistical Process Control is used to detect when a significant change has taken place in a process.  We want to detect this change as soon as possible. What is real-time will depend on the process.  All processes have variation as observed in any of their metrics but not all variation is significant from the statistical point of view.  Random Variation Vs Trends: Statistical Process Control When we want to control a process by adjusting some process parameter we can make two mistakes: Over-react by adjusting when we shouldn't Under-react by failing to adjust when we should Control over-reaction A case of over-reaction is illustrated by the following example: Someone is shooting at a target and, based on the deviation of the impacts, he adjusts the gun site after each shot. The end result will be an increase of the dispersion of the impacts, therefore the adjustments will make the process worse. The correct way is, of course, to fire 5 or 6 shots with...

Time variation and WIP cause a vicious circle that increases value stream lead time making it difficult to keep pace with changing customer demand. Time is a continuous variable which can be easily recorded without the need of special equipment: PCs or smartphones used to collect data can automatically record a timestamp. When it comes to analyse cause and effect between process parameters and results time is key. Time Variation Causes Accumulation of WIP You can experience this effect in exercise 7 with a simulator  : This WIP Increase Causes a Lead Time Increase As seen in the same simulator: This is due to the fact that items have to wait in the queues formed before steps 2 and 3. Long Lead Times Cause an Amplification Upstream of the Market Variation  This effect is well illustrated in the Beer Game  which can be experienced with various simulators in the web. The game was first described by Peter Senge  in The Fifth Discipline . A small variation in the market ...