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When The MPS Is MIA ...

By Chris Gray, Gray Research 

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Have you ever heard the old saying “The devil is in the details”?  When it comes to managing production, inventory, capacity and the flow of work in a modern supply chain, nothing could be more true. 

Even if you’ve done a great job of balancing supply and demand in aggregate … even if you have enough capacity in total based on anticipated production volumes … even if there’s plenty of inventory in aggregate to satisfy expected demand … the devil is in the details. 

In all these cases, managing the details – knowing which products to make, and which specific ones to make first and which second and which third, and how much of each should be produced to satisfy demand and also promote maximum flow – is a function of your master production scheduling process.  Do a poor job of creating a leveled MPS where supply and demand is in balance, and a poor job of managing it in the face of change, very likely you’ll see one or more of the following: 

  • A double whammy:  excess inventory and poor customer service. 

  • Capacity problems – overloaded or front-loaded capacity plans (in spite of what was agreed in the S&OP process). 

  • Excessive numbers of past due orders.  

  • Rush manufacturing jobs and lots of expediting. 

  • Excessive numbers of planning system action messages – many of which may be “unactionable”. 

  • Constant “churning” of the schedule as customers jostle with each other for priority. 

  • No user confidence in the system and lots of second guessing of the schedules and work authorizations. 

  • An informal system creeping back to try to answer the question – “what do we actually need and when do we really need it?” 

Of course, no one sets out to do a poor job of master scheduling.  But lots of excuses and half-truths later – “we’re made to order and don’t need all that master scheduling stuff”, “we’ve become a lean manufacturer and lean precludes it”, “we have too much change and it’s too much work”, “we have a lousy forecast (or erratic customer schedules) so we can’t do master scheduling” – and suddenly the MPS is missing in action. 

You really owe it to yourself to do have a professional master scheduling process that is synchronized with your aggregate planning processes (S&OP and rough cut).  Do it well, do it often enough, do it completely, and within the context of effective aggregate S&OP and you will typically lower inventory and simultaneously increase customer service, create smooth workflows and predictable use of capacity, establish smooth and predictable transitions from one product to the next to the next, improve on-time performance and eliminate past due work and the constant expediting that goes with it, reduce the number of customer complaints (and the factory churning that often goes with them), and establish a single system that will answer the question “what do we really need first, second, third … and when do we really need them”.  

Do a good job of creating and managing the master production schedule – in the details – and you really will have gone a long way toward exorcising the demons that make supply chain management so challenging. 


Chris Gray is the president of Gray Research and can be reached at . Over the last twenty years, he's helped more companies sort out manufacturing and distribution software issues than any other individual in the field and has authored three books on this topic. 


If you need to evaluate or upgrade your master scheduling practices, see the newly updated Partners for Excellence courseware: 

Master Production Scheduling Instructor’s Guide

Advanced Master Production Scheduling: Dealing With Products and Options

Do you need to educate people on key concepts like Master Production Scheduling and want self-administered programs (your venue, your instructors) that you can run at your own pace and on your own schedule? 

Master Production Scheduling Instructor’s Guide - was specifically designed to support timely, focused, self-administered education. That's your people conducting a master production scheduling class using professionally developed materials from our library of course material.  

Advanced Master Production Scheduling: Dealing With Products and Options - is a four hour video-based education course focused specifically on the needs of companies assembling or finishing products to order from options.  Featuring John Dougherty, this DVD will introduce you to some important concepts for managing a finish to order environment.   




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If you have specific questions about this article or want to discuss it with the author, call Chris Gray at 1 603 778-9211.


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