How to Create a Product Quantity / Product Routing Matrix

Product Quantity / Product Routing MatrixUpdate (4/4/14): We recently released an excellent podcast with Karen Martin on the topic of Value Stream Mapping.  You can listen to it by clicking here.

In part 1 of our series on value stream mapping (VSM) we were introduced to what a value stream is. We also discussed the roadmap I personally use when working with this powerful tool.

In this installment, we’ll take a deeper dive into another very important tool that should actually kick off any VSM activity – the product quantity / product routing (PQPR) matrix.

Product Quantity Matrix

In order to garner maximum benefits from your value stream mapping efforts, it is important to take some time up front in order to identify the product family you wish to study and improve.

The first tool I recommend you look at is a product quantity matrix. The basic premise here is that you should target your higher volume products for improvement first. Here is a 2 step roadmap for doing just this.

  1. Collect production output data – both in units shipped and sales figures. As a starting rule of thumb I recommend attempting to collect 6 to 12 months worth of data.
  2. Create a Pareto chart with this data in attempts to identify where to focus first (e.g. highest volume products).

In some cases you may have two results. The first place “winner” based on units shipped may be product ABC. However, the first place “winner” based on sales dollars may be product XYZ. In these situations it is up to the management team to make the call as to where to focus.

Since this is all based on historical facts, you can tweak this method ever so slightly by including forward looking forecasts. But be careful… since the only thing certain with a forecast is that it’s certain to be wrong.

Product Routing Matrix

If the results of the product quantity matrix are inconclusive we can look at another tool – the product routing matrix.

With this tool we are interested to learn how each product family moves through the process. For example, do certain products pass through the exact same machines? If so, we can actually group them together and create one set of value stream maps covering both products.

Combing the Tools

While each of these tools can work well on their own, it is my opinion they are at their best when working together.

In the picture above (click to enlarge it) we see that ABC took the prize for most units shipped, and XYZ made us the most money.

Then, when we looked at the routings we saw that ABC and QRS actually went through the same manufacturing steps. Further, product QRS was a close second place on sales $ and third place for units shipped.

So, in this example the team decided to map product ABC and QRS together.

Summary

That’s really all is there is to this tool.  Obviously, real life examples will be far more complex than my simple scenario.  But the process you use should be no different.

Lastly, this same process works in front office/transactional environments as well.  Instead of looking at machines you may instead look at how a piece of paper flows through the office (e.g. which functional departments touch it).

If you are enjoying this series on value stream mapping please subscribe to LSS Academy via our RSS feed.

Read the next article in this series: Let’s Create a Current State Value Stream Map!

6 Comments

  1. Bruce Henne

    March 28, 2010 - 10:08 am

    The first step before value stream mapping a Process is to make sure you have people involved that understand the process and the steps within. This may not be an issue for realatively simple to understand processes but many manufacturing processes have complexity to them and optimizing these more complex sub-process steps may actually be the big hitter in overall improvements.
    Second, single piece flow in manufacturing is actually not the way to go. Its wrong. It was a result of VSM’s created from people not understanding the complexity within processes particularly where equipment, multifunctional electromechanical and/or chemical reactions are being performed.
    Single Piece flow is for low flexible volume manufacturing.

    Flexible Batch processing is the actual correct way to produce most modern manufacturing products. Each work cell will have the right size batch in order to pull from the downstream process at an economical level depending on all cost factors from raw material ordering to product delivery.

    Also, flexible batches include batches of size = 1.

    Batch control is the state of the art methodology and it is actually somewhat of a misnomer today as it spans single piece flow to continuous processes of mega size. Why the name then – it is related to the control philosophy and evolution of process control methods and software over the last 30 years — thus predating most quality efforts. It was often the one place in a plant where one could walk in and see SPC charts predicting precise outcomes hanging over a piece of equipment right sized for its production volumes. Intelligent science and engineering together with model predictive control methods were used. These would be similar to Robust Design today with all CTQ’s or KPIV and KPOV’s controlled and verified in real time.

    Unfortunately these processes have continued to get better and better without tooting their horn because they were often running at very high 98 to 99+% efficiencies 24/7/365 and without large problems to solve not much noise was made.

    You will here more about these high end process control methods as the US if not the world appears to be on the verge of Generation III of manufacturing improvement. Six-Sigma and Lean are great tools but there is an over-application and misapplication of the LEAN tools — but in a good way — every new improvement method now days is being called LEAN. Its not bad, but mislabelling can lead to confusion. What may be happening is the prolific use and common language created by LSS methods may be driving enough common acceptance of the underlying improvement tool attached to “LEAN” that it is being tried and used. The actual underlying foundation for improvement in any area is deep knowledge and wisdom. In manufacturing that foundation is primarily in science and engineering at the shop floor but supported by transaction based and business logic based support from the service and management levels. Thus is one is talking about a LSS project on improving a semiautomated manufacturing process that uses people, machines, computers, people, mechancial and chemical transformation steps then the science and engineering tools all impact the creation of knowledge and wisdom contained within these processes. Lean evolved as a nice almost common sense improvement one can do Once one’s processes were understood and controlled. Six-Sigma evolved as a 2-dimensional slice of the spehere of science and engineering used to create most manufacturing processes. Science and engineering are one sphere of intersecting spheres of influence necessary to complete a whole business system.

    So keep your perspective and grow the wisdom seeking out and bringing in knowledge and using methods from all the spheres of influence to perfect manufacturing in our Phase III – 21st century manufacturing.

    • Jason Farley

      July 16, 2015 - 3:45 pm

      “Lean evolved as a nice almost common sense improvement one can do Once one’s processes were understood and controlled.” – quantity control once quality control is established… a fundamental misunderstandings by many Lean pros today.
      I really enjoyed reading your response and couldn’t agree more. The use of a combined scientific and engineering approach is not new but technology and its application are and will always be new… dynamic. Also, the evolving demographic in industry where old school, first generation Lean and Six Sigma (and really TQM) thinking meet new generation technologists is really interesting. Being embedded will not help the old and being ignorant won’t help the new. I like the way you elevate the issue above any one school.