Steve Beeler

You have a goal…I have a way to get you there.

Toyota Production System

Variation and Waste

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Variation is at the root cause of almost all waste in manufacturing and business systems.  It is no coincidence then that variability reduction is the foundation for the Toyota Production System (Lean Thinking) and its success in continuously reducing waste.  Two games of chance with dice and cards illustrate the linkage between variation and waste.

The first game is a single piece flow system with five machines.  The output of each machine is represented by the total of two dice.

The average of two dice, of course, is 7.  However, our five-machine system only averages 4.3…a 38% loss!  Why?  Variation and waste.  In single piece flow, no machine can outproduce another.  Production is lost through waiting losses (blocks and starves) when the machines interact with each other.  Balanced and dependent systems are surprisingly common.  They never work as expected.  In isolation yes, in combination no is a key lesson from Theory of Constraints.

The second game is a system of three machines feeding an assembly area.  The output of each machine is represented by the draw from a deck of cards.  In order to assemble a product, all three cards must match.

Variation and Waste

Each machine is produces one card per time period.  Jokers represents a defective product and cannot be matched.  The decks are shuffled so the three output sequences are independent.

Variation and Waste

Quite a few cards collect (to the right of the decks) before there are matches for the assembly machine to assemble (to the left of the decks).  Work in process inventory (WIP) and lead time are horrendous.  Throughput suffers as the assembly area waits for matches.  In isolation, each machine is successfully producing cards.  In combination, the system is performing poorly.  Variation and waste again.  This time the variation is in sequence, but the waste is equally dramatic.

Variability reduction is a big part of my day job as a Professional Engineer.  Visit my Operations Engineering page for methods and case studies.  While variation is always present, robust systems can be designed  to minimize the linkage between variation and waste.

Lean Thinking in NASCAR

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Toyota may have only been racing in NASCAR for the last decade or so, but the principles of the Toyota Production System have been in the sport since its inception. Here are some examples of lean thinking in NASCAR, that uniquely American form of motorsport:

Lean Thinking
NASCAR Pit Stop

Single-Minute Exchange of Die (SMED). A pit stop is the NASCAR equivalent of a die change in manufacturing. Quite a bit gets done in only a few seconds: tires are changed, gasoline is dumped in, and chassis adjustments are made. A number of lean thinking techniques are utilized in a NASCAR pit stop:

(1) Separate Internal from External Setup Operations. Most of the work performed in a NASCAR pit stop is actually done while the car is on the track: tires are mounted, balanced, and set to the right inflation pressure; gas cans are filled up; adjustments are discussed over the radio; and everything (and everyone) is organized along the pit wall.

(2) Convert Internal to External Setup. Lug nuts are glued to the wheels so that they do not have to be positioned before being secured. Special tools have been designed for things that are frequently adjusted for changing track conditions (track bar, wedge, etc).

(3) Adopt Parallel Operations. One person could perform all the operations in a pit stop…but a carefully coordinated team can do it much faster. Everyone in a NASCAR pit stop has a job to do…and does it with very little wasted motion.

NASCAR engine bay
NASCAR Engine Bay

Countermeasures for Zero Breakdowns. Mechanical reliability in NASCAR is excellent. With the exception of a few cars too damaged in wrecks to continue, almost all the cars that start are running at the finish. All five Total Productive Maintenance (TPM) countermeasures for breakdowns are readily evident:

(1) Cleaning, lubricating, and bolting. The cars are meticulously assembled and then receive lavish amounts of attention during a race weekend. A small fluid leak will only get worse. Brake dust could be hiding a problem.

(2) Adhering to proper operating procedures. Detailed checklists coordinate and control everyone and everything that touches the car.

(3) Restoring deterioration. Virtually all parts are inspected between races. Many, like engines, are replaced after every race.

(4) Improving weaknesses in design. NASCAR teams have rigorous engine dyno programs to improve engine reliability. Redundancy is provided for systems with less than 100% reliability: electronic ignitions, batteries, etc.

(5) Improving operations and maintenance skills. Self evident…the cars get faster and more reliable every year. A very high level of organization is required to run a NASCAR team.

Shigeo Shingo and Junior Johnson would have had a common language in lean thinking…

Here are two books from my library on TPS and TPM:

“A Study of the Toyota Production System” by Shigeo Shingo (the famous green book)

“Introduction to TPM” by Seiichi Nakajima

Addendum – February 18, 2022

While watching a bit of last night’s Daytona 500 twin qualifying races, I noticed another example of Lean Thinking in NASCAR…centerlock wheels.  The new “mono lug” forged aluminum wheel is example of another common SMED technique: Use Functional Clamps or Eliminate Fasteners Altogether.

An image comparing NASCAR 5 lug and mono lug wheels

Centerlock wheels are nothing new in motorsports but NASCAR has always raced on 5 lug steel wheels.  The rules change to forged aluminum centerlock wheels reduces the number of fasteners (and time) required to remove and reinstall a wheel.

Dumping in fuel may now be the “bottleneck” in a NASCAR pit stop (pun unintended).  It will be interesting to see how pit strategies are affected.