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Lean 101

Motivating example — unloading your dishwasher

Enter the world of "lean" by thinking through a day-to-day activity - unloading your dishwasher. You will be surprised at what there is to optimize!

Nikolaus Correll
July 22, 2021

Motivating example — unloading your dishwasher

This lesson introduces the basics of “lean” thinking. What “lean” is, is difficult to define. In a nutshell, “lean” refers to a framework that not only helps you to do more with less, but also helps you to evaluate what “more” and “less” mean. It is difficult to learn lean thinking from a book. Instead, lean is best experienced at what the Japanese refer to as “genba”, literally “the actual place”, or the “crime scene”. This does not mean that you cannot experience and learn “lean” by immersing into a good narrative or by putting theory into practice at home. In fact, the most successful books on lean of all time come in the form of “business novels”, which might really be the only way to appreciate the holistic aspects of the lean mindset. In this spirit, this lesson uses a daily chore, unloading your dishwasher such as shown in Figure 2.1, as a motivating example to prepare you for “the five steps to lean” and “the seven deadly wastes“, both core-concepts of lean organization.

Have you ever wondered why unloading a dishwasher is so annoying, while loading it is actually not too bad?

What is your goal?

What it is that makes unloading the dishwasher so annoying? Is it that putting dirty dishes away and starting the machine is simply more rewarding? Do we know that we are trapped in a highly inefficient process, akin biking uphill on a slight incline, just steep enough to slow us down and never get us “flow”? Or, does the task always happen at the wrong time when the rest of the family has already moved on to the next fun activity?

As we cannot really pinpoint what it is that makes unloading the dishwasher so unrewarding, let’s focus on getting it done as quickly as possible. Time is easy to measure using a stopwatch. How can we go about decreasing time then? Is it to try to move as quickly as possible, risking that we break a dish every now and then and are completely exhausted or even hurt once we are done? Probably not. We are rather interested in simple changes that do not lead to increased tear and wear on both dishes and people, but being able to do more with less.

Map out the value stream

Let’s look at what emptying the dishwasher actually entails. As each of these steps add value to the task, we also call them the ”value stream”. The first task is taking items out. Second, items need to be moved to their storage locations. Third, we need to place items in cupboards and shelves. An obvious first target for improvement is clearly to minimize ways during transportation. This leads us to our first improvement: Storage locations should be as close to the dishwasher as possible.

For example, left or right above the dishwasher for light dishes and left or right next to the dishwasher for heavy pots minimizes not only transport, but also motion and heavy lifting. Optimally, one would elevate the dishwasher just enough that bending motions are reduced. All of this is often not possible in most kitchens, and most adventures into “lean” end when the obvious improvements are not applicable. Fortunately, the dishwasher problem — as most trivial looking problems in manufacturing — is surprisingly deep.

Also, giving up now is actually fatal. Not having access to an optimal storage location is already a problem and indicates a highly sub-optimal process. Even more effort should therefore be put into optimizing your second choices. Most people don’t do this, however, as they are frustrated by not being able to do the obvious and underestimate the big impact that the sum of small changes can have in the long run.

The next question you should ask yourself is whether you can get away with a more compact assortment of dishes and cutlery that can indeed be stored in a more optimal location. While the answer here is “no” for most people, and there indeed is an occasional need for even the fanciest sauciere, this leads to a consideration of frequency of use. With this, we can derive our second improvement: Frequently used items should be stored in the closest location, those less often used should be stored in the furthest available location.

This optimization has probably already emerged in most households, and if it has not, this has probably been one of the most useful articles you have read in a year. But there is more we can do.

Create Flow

Now that we have minimized transport that is required to solve the problem by optimally assigning item groups to a set of locations, it is worthwhile to take a closer look at what actually happens during the transport that cannot be avoided.

Our first realization is that we would want to carry as much as possible everytime we go. This becomes pretty clear when imaging that walking back and forth between the drawer and the dishwasher for every single spoon will take much longer than moving the cutlery by the handful. This directly informs how we carry out the emptying task — we should try to grab as much items as we can before going anywhere. This leads to a third suggested improvement: Many more items can be carried when stacking them, we should therefore focusing on unloading items in groups of identical objects.

It turns out that some items stack better than others. For example, one can easily grab 10-15 spoons in a single hand or stack 10 or so dishes, but I have a much harder time with glasses, moving only two in each hand. Glasses also don’t stack well with mugs, which don’t fit with wine glasses and so on. This introduces a second “frequency” in our consideration. Some groups of items, such as dishes, can be moved during one or two trips, whereas glasses and mugs require many trips. This can be condensed into a fourth piece of advice: Groups of items that require many trips from dishwasher to storage location should be closer than groups of items that can be stored in fewer trips.

Now that we better understand how to speed up the unloading process, we might also want to think about how to load the dishwasher. In an ideal scenario with storage to the left and the right of the machine, we should load items accordingly. As we want to grab as many items as possible and stack them, items should also be loaded this way. This can usually be achieved without any additional cost, but pays off downstream.

Has everything been said about the dishwasher unloading problem? Far from it.

For example, now that you have minimized transportation, it might make sense to think about moving item groups on a tray. This bears the question whether reduced round trip time justifies the additional manipulation (placing and picking from the tray). This problem can probably only be solved using a stopwatch. It is also interesting whether transport could be completely reduced by working with a partner who is strategically placed and to whom you can hand over items. Whether this approach is more than double as fast as when you do it alone (super-linear!) will depend on whether you can balance your line, that is reduce waiting for either you and your partner while one is storing or retrieving an item. Also, now that every second counts, opening and closing cupboards and drawers becomes a nuisance. While good organization and planning can help to open and close each cupboard only exactly once, some might start thinking about structural changes and remove unnecessary doors.

Create “pull”

Lean makes it easy to get carried away in details, however. There are two very big no-nos that would trip off even the leanest approach. First, not everything in the dishwasher might actually need washing, but instead could have been stored right away or after a quick wipe-off. But what is really the dumbest thing one could do? Putting dishes away right before setting the table. Therefore, always grab dishes from the clean dishwasher and only start it once you start running out on critical items.

So what about all the dishes waiting in the sink? An obvious solution would be to replace one of your cabinets with a second dishwasher. This dishwasher would then serve as a “buffer” , while you are living out the “clean” dishwasher, and will need to be started once you begin running out of necessary items —- a triggering event known as “pull” in lean organization, whereas triggering it based on a pre-made plan is known as ”push”.. We will talk more about the exact definition of pull systems in Chapter 7.

This might also require starting to fill the “clean” one with dirty dishes before it is empty, which is not very ecological. This brings us back to our first question: what is your goal?

Pursue perfection

You should now have a pretty good idea of how a typical lean optimization task looks like. What looks like a simple task with little room to improvement actually has tremendous optimization potential, depending on what your goals and constraints are. Surprisingly, new ways of doing things also shed light on new potential targets and constraints, making your journey to lean a never-ending process.

The main reason for this is that what initially appears as a collection of rules turns out to be a set of contradictions. Toyota has understood that and describes lean with the “true north” analogy. A compass needle gives you very good directions to the North pole until you get actually close. Then, the compass needle will point you to the magnetic north pole (which is not quite where the geographic pole is) and eventually let you turn in circles. Analogous, the closer you approach optimality, the less you can rely on simple rules of thumb, and the harder you need to work to squeeze out the last little bit of optimality.

Exercise 1: Lean improvements
Volunteer to empty the dishwasher at home. Use your smart phone’s timer function to take time and think about you can improve your existing process. Implement changes one by one and keep taking time over multiple days. How much faster have you become after one week?

 …but I don’t have a dishwasher in my factory

The dishwasher is a great example as it packages a lot of complexity into a familiar device and all its challenges are all visible at the same time. After all, all of the issues above can be experienced without moving around and happen at the time scale of a few minutes. This is not the case in a factory, where the value stream might involve many different machines and manual labor steps that are distributed across multiple buildings and happen at the time scale of multiple days.

Studying such a system is therefore orders of magnitude more complex and finding ways to visualize the value stream and getting statistics (or better, real-time information) is often the first step.

Quiz

1.What are suitable goals in optimizing the unloading process?

  1. Unloading as fast as possible
  2. Unloading without breaking one’s back
  3. Getting other things done in parallel
  4. Saving as much energy and water as possible
  5. All of the above

2.Which of the below makes the unloading process take longer?

  1. Items breaking
  2. Bending down
  3. Too many different items
  4. Moving items from the dishwasher to a shelf
  5. Washing items that were already clean
  6. Waiting for other people to move out of the way
  7. Putting things away that will be used right away
  8. All of the above

3.What is a possible reason to sometimes wash items by hand?

  1. Sometimes waiting for the machine to be done is unacceptable.
  2. Washing by hand can be cheaper.
  3. The machine sometimes does not perfectly clean.
  4. All of the above.

Solutions: 1-5, 2-8, 2D

ABOUT THE AUTHOR
Nikolaus Correll

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