Lean and the digital factory: is the digital twin the new gemba?

The digital twin is the virtual and digital copy of a factory allowing monitoring, post-mortem analyses, simulations, stress tests, machine learning and much more.

As a Lean practitioner having started his Lean experience in the 1980s, I faced the difficulty to get engineers, techs and sometimes foremen to the shopfloor to assess and understand the situation, and support the operators.

The author (left) at Yamaha's headquarter in Hamamastu, Japan

The author (left) at Yamaha’s headquarter in Hamamastu, Japan

With the growing ability of the digital twin to get closer to the physical reality, my prospective question is: can the digital twin become the new gemba?

Not familiar with digital twin? Checkout: https://en.wikipedia.org/wiki/Digital_twin

Is the digital twin the new gemba?

My first answer would be no, for 2 reasons :

  1. The digital twin dies not correspond to the definition of gemba
  2. The digital twin is like Magritte’s pipe : a representation but not the real thing


“Gemba” (Japanese word) was long translated into the “real place” or “where it happens”, in Lean parlance where value is (supposed to be) created. This emphasis on the reality is a warning against the spreadsheet analyses or the tendency to trust blindly data.

Until recently, data taking was mostly manual and tedious, thus limited, and error prone. Trusting data meant taking chances by trusting a limited set of data to draw conclusions and/or being misled during analysis because of all the limitations and errors.

Compared to data analysis, going to the gemba and perceive the situation by oneself always gives a way better understanding and appreciation of what happened or is going on. The human body with its natural sensors can grasp more of the reality than the best and most accurate description.

Intuition can work better in this environment as more senses are stimulated. Links are established between distinct phenomenons or events, something that an analyst may not perceive when working only on a dataset.

This doesn’t mean that data are useless, simply they may not be used exclusively in order to widen the scope of the investigations and analyses.

The digital twin

Now what is a digital twin? A really big collection of data that allows to simulate the real-world twin,with growing fidelity and getting closer to reality. But it is still data however their amount, and not the real place.

On the one hand immersing oneself into the virtual reality may allow exploring it in ways that are impossible in real world. The digital simulation can take an analyst virtually into a working machine and show the dynamics of the various components. Digital monitoring can even capture what the human sensors are unable to, thus ”augmenting” humans.

But on the other hand the sensors collecting data, however performant, capture only a limited reality. For the time being and as far as I know there is no smell in the digital twin, no sound like the squeaking or screeching, and heat can be measured but is not “played back” as heat in simulation, or is it?

There is no life in the digital twin, no unexpected insects, birds or rodents causing unforeseen problems. Vibrations can be measured and simulated, but is it as subtle as real vibrations and trepidations? Air flow will only exist in the digital twin if sensors or the digital model was designed to measure or simulate it. And the leaking roof problem may not exist in the digital model. Such examples are still countless.

In short, virtual reality may be closer to reality now than ever before, but still isn’t reality. And if it is not reality, it is not gemba.

Magritte’s pipe

Magritte’s painting of a pipe is a pretty realistic picture of this smoking accessory, with the caption “this is not a pipe”. Many of those recognizing a pipe would think of course this is a pipe! but the painter wanted to remind viewers that the pipe is only the picture of a pipe, not a real pipe.  So is the digital twin. A pretty good representation of reality but not the reality.

The digital twin could become the gemba of the future

Now, in order for the digital twin to be considered the new gemba, it suffice to change the definition and get consensus about it in the (lean) community.

If a majority of people and lean practitioners consider the digital twin worth to be considered as gemba, or the actual definition of gemba being altered to encompass the digital twin, so be it.

I would not support this idea for the sake of clarity though. Think about the word “kanban” that for decades described a pull system in manufacturing and supply. Then the IT community adopted Lean principles and came up with its own version of kanban. It is built upon the same principles, describes a pull system, but is different enough to generate some misunderstandings.

Your thoughts?

About the author, Chris HOHMANN

About the author, Chris HOHMANN

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What is a logical “long arrow”?

In Logical Thinking Process (LTP) parlance a long arrow is a “leap of logic” or the omission of one or several cause-and-effect steps that connect a cause to an effect.

In the Logical Thinking Process, a cause is linked to its effect by an arrow. The arrow’s tail is connected to the cause and the tip points to the effect. Hence the reference to the arrow.

In the picture, the cause is at the bottom and the effect is on the top.

Ellipses are logical “AND” connectors. Arrows going through an ellipse read “if…. AND if… then…”

Some may refer to the AND connectors as “bananas” but I would not encourage this.

The “long arrow” skips several “if…then…” or cause-and-effect relationships, also considered as logical steps.

Leaps of logic are to be avoided for the sake of logical soundness. Long arrows are likely to confuse an audience as the listeners or readers cannot naturally link the things together.

True listeners may have difficulties to follow the speaker’s logic or readers might get confused, lost or perplexed while reading a text.

Many people speak or write long arrows because the sequence of causes-and-effects is clear in their mind. They don’t pay enough attention how their thinking can be received by someone not knowing about the subject, the unspoken assumptions or the implicit and skipped relationships.

The more logical steps or cause-and-effect links skipped between a specific cause and an certain effect and the longer the arrow.

In the scrutinization process of logic trees, long arrows are generally considered as “mistakes” or at least “logical improvement points”. Long arrows are not officially considered as Categories of Legitimate Reservations (CLR), but could in fact. Long arrows should be broken into more detailed steps in order to get the faulty tree more sound and robust from the Logical Thinking Process point of view.

About the author, Chris HOHMANN

About the author, Chris HOHMANN

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The tablet syndrom

This post is not about drugs nor pharmaceutical industry, the mentioned tablet is the electronic one, you know, the bigger version of a smartphone.

The tablet syndrom is about the tablet as a symbol for being trendy, going digital, sometimes even believing to lead a digital transformation when handing out a load of these devices.

I happen to visit a broadcasting and publishing company and while waiting for my contact to pick me up, was invited to wait in the visitors’ waiting room.

The first thing I got to see was a tiny room next to the waiting room and separated by a glass partition. In full view of every visitor was the mess in this room, obviously collecting parcels coming in or shipped out among other stuff.

Next was a collection of sofas and room dividers in an arrangement looking more like stranded by a kind of tsunami than a practical one to accommodate waiting guests. To reinforce the impression of a past catastrophe were some armchairs upside-down as well as a short table tipped over.

The storm must have swept out the water fountain because nothing alike was to be found in the room nor in the entrance.

It is obviously a cultural trait of the media companies to have messy and cluttered offices. I think most of the worst clutter piled behind office windows are in media companies buildings. They never heard anything about 5S I assume, and if they did, had probably dismissed the idea of tidiness as “vulgar”.

What was available in abundance in this visitors unfriendly place were the latest issues of the magazines this company was publishing, as well as a collection of huge tablets on the wall, displaying their digital versions.

The tablets were functional, meaning reactive to my finger sweeping.

This is a kind of tablet syndrom I thought. Nothing is really fit for purpose in this room, supposed to provide a nice and convenient place to wait, but the tablets were there, plenty of them.

It reminded me some factories, messy and having poor performance, but the management proudly show you the latest tablets with all KPIs displayed in fancy colors.

Hanging plenty of huge tablets on the wall did not much to improve the waiting room, just as displaying lousy KPIs on a shopfloor tablet does nothing to improve performance. At best, it may distract the visitors’ attention from what is really important. The irony is that in most cases it also blinds managers from the reality of the situation…

That’s what I mean by tablet syndrom.

Comments welcome.

About the author, Chris HOHMANN

About the author, Chris HOHMANN

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Holidays, flow and common sense

This article is an afterthought of what I have seen the previous week during a nice holiday abroad, an so many times before.

It is a rather common experience. We booked a one week vacation in a nice sunny place, with palm trees and a hotel that seems to match our requirements. We choose half board and to have our dinners in the hotel’s restaurant.

As so often, the courses are offered as buffets: starters, main course, dessert and cheese and fruits. I assume buffets are a convenient way for the staff to accommodate many customers showing up in unpredictable waves as well as giving them the feeling of unrestricted access to all food they like.

Now the various dishes on the buffets are arranged like so often machines in a factory: similar close to each others yet placed where some place is found. And most important, without much consideration for flow.

In our case, guests are visiting the buffets from any end, jamming and almost colliding in the narrow alleyway with their hauls, while hesitant people just stay pondering their next possible choice in the middle of it.

The hot dishes buffet is set behind a huge pillar, providing more opportunities for guests collisions, as those coming around one pillar’s corner can’t see the human traffic that will emerge in front of them, and conversely.

The dessert buffet was maybe the worst, because it was set in a one-way, dead-end kind of corridor.

Sounds stupid, not efficient? I do think so.

Now, did any of the numerous managers of this place think about efficient, seamless customers’ flow? Probably not much. Disappointing as so often, as I thought restaurant and hotel professionals should be experts on how to organize a buffet. And not only from the nice looking perspective. Over time I gave up with this assumption that showed false so often.

Who said common sense is common?

Now to be fair, if I conducted a survey with the customers in those restaurants, I would probably have very few analyzing the situation as I do. My guess is that most of the guests accommodate themselves to the traffic and layout and focus on the display of food instead. What would they answer as to their user experience? Food was great / good / plenty / fresh / refilled…

Well this is the trouble being a consultant making a living with operational excellence, you just can’t switch completely off during holidays.

About the author, Chris HOHMANN

About the author, Chris HOHMANN

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4 reasons to consider SMED

SMED is a structured approach to reducing changeover durations. Here are 4 good reasons to consider deploying SMED.

>Lisez-moi en français

1. More production capacity is required

A critical resource of the production process is not able to deliver the expected quantity, due to lack of capacity. Such a resource is usually called a bottleneck, and chances are that a quick analysis will show that changeover durations are one of the major factors of capacity wastage.

Rather than reducing the number of changes and extending the series, it’s better to work on reducing the duration of changeovers from one series to the next in order to recover wasted capacity.

In many cases the gains through the application of the SMED method are sufficient to recover the lacking capacity. If it’s not the case, it is then necessary to check the distribution of the causes of capacity wastage (via a Pareto diagram, for example). Machine downtime due to breakdowns or quality issues discarding a part of the production may be additional themes to deal with.

2. More flexibility is required

When production capacity is sufficient but there is a need to better stick to the demand, this can be achieved by changing the productions more frequently.

Indeed, for a customer waiting for a given product, the waiting time is function of the length of the queue of orders to process before launching the production of the expected product, the lead time of the production process itself, and finally the shipment process.

The reduction of the batch sizes and the multiplication of launches help reducing the global lead time. For this solution to be viable, however, it is necessary that the multiplication of changeovers does not cause the production capacity to fall below the required level, otherwise we find ourselves in the previous case.

To prevent this risk, the duration of the changes can be reduced by applying the SMED method and converting the time gained into additional changeovers.

3. More machine availability is required

In this third case there is no shortage of production capacity nor lack of flexibility but what is lacking is time during which a machine is available for periodic maintenance operations, or for processing exceptional additional orders.

In this case also the reduction of the duration of changeovers may be a solution to consider. The recovered machine availability may then be used as needed.

4. Freeing time of experts

This case is rare, but may arise, especially in environments that are strongly constrained by standards or regulations and in which changeovers require the assistance of personnel with special qualification and/or authorization. In these cases it is no longer the capacity or the availability of the production means which is limited but those of these “experts”.

They may be required simultaneously for different changeovers and their limited availability may adversely affect the overall performance of production, with some machines, equipment or lines waiting.

Take care of adjustments and tests too

The term “changeover” is sometimes interpreted as the change of dies, or the change of settings only. A changeover should include the clearance of everything related to the completed series and the resuming of production with the new series, new reference or new batch, at nominal speed. This means that all required adjustments and tests have been performed and their durations have been counted as part of the changeover.

Excluding these durations in order to pretend to change over quickly may leave them out of the scope of improvements, which is a loss of improvement opportunity and only a partial application of SMED.
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Smart Factories: Converting workers into problem solvers?

About the author, Chris HOHMANN

About the author, Chris HOHMANN

Smart factories, industry 4.0, IIoT and everything else covered by the digital transformation umbrella raises fear about the future of human jobs, or to be more specific, the income source of employees.

To my surprise some promoters of these factories of the future have a ridiculously simple solution: convert the actual workers into process supervisors and problem solvers, without questioning the paradox of the need for supervisors and problem solvers when processes will be – allegedly – way more reliable, constant, repeatable and even self improving.

>Lisez-moi en français

Even so the assumption of required supervisors and problem solvers is valid, I do believe that the number of freed workers through automation, robotics, etc. will exceed the number of required supervisors and problem solvers.

If it would not be the case, it is the benefits of the promoted solutions that are questionable. Especially if many more problems solvers are required, it should raise concerns.

Besides, as I am not impressed by most of the actual, traditional manufacturing problem solvers’ capabilities and achievements, I cannot believe they will do much better with technologies requiring even keener knowledge.

Am I wrong?

Am I the only one perplexed by this “solution” for converting the redundant people?

Your thoughts are welcome.

Why you cannot use tentative language in a logic tree

I once happen to see a Current Reality Tree cluttered with “coulds” and “shoulds”. Conditional or tentative language cannot be used with logic trees and here is why.

Cause-and-effect (sufficiency logic)

The Logical Thinking Process logic trees use either sufficiency or necessity logic. Sufficiency or cause-and-effect relationship states that a cause, if it exists, is sufficient by itself for the effect to happen. Using conditionals like should or could violates the sufficiency principle as it suggests that the cause is not always producing the effect.

The Current Reality Tree (CRT), Future Reality Tree (FRT) and Transition Tree (TT) are built on sufficiency logic and therefore cannot hold any entity with shoulds or coulds.

If a should or could is found in such a tree, the scrutinizer must raise a “cause insufficiency reservation“. The statement must then be corrected, for example by adding one or more additional cause(s) combining to the first one with a logical AND connector. If this combination is valid, the sufficiency relationship is restored and should or could is removed as the effect is now guaranteed to happen.

If no additional causes can combine to the first one, the cause-and-effect relationship is probably only assumed or false. Anyway no should or could can be left in a logically sound tree.

Using present tense

The entities – the building blocks of the logic trees holding the statements – must be expressed in present tense.

Using present tense is natural in a Current Reality Tree (CRT) as it is the description of the actual situation, the cause-and-effects relationships that exist right now.

The use of present tense in Future Reality Trees (FRT) is highly recommended even so these future situations and the Desirable Effects do not yet exist. Present tense helps to project oneself and the audience into the future and visualize the situation as it were already improved (Scheinkopf, “Thinking for a change, putting the TOC Thinking Processes to use”, p119). Dettmer also recommends to use positive wording (Dettmer, The Logical Thinking Process, p244).

This applies to entities in a CRT, a FRT and in a Prerequisite Tree (PRT) which are verbalized in full sentences.

What about necessity-based logic?

Can necessity logic based tree use conditional/ tentative language?

The Goal Tree (GT), the Evaporating Cloud (EC) and Prerequisite Tree (PRT) are built on necessity logic. They describe the chains of enabling conditions that are required to achieve a goal or an objective. Without the enabling conditions, the objective cannot be attained. Conversely, with the enabling, necessary conditions fulfilled, the objective will not automatically be achieved; additional action is required.

As the Desired Effect is not guaranteed to happen even so all necessary conditions are fulfilled, the use of conditional / tentative language seems legit. Practitioners would not use it though.

First because we need to demonstrate positivity about a desirable change and help the audience to mentally visualize the future where things happen and produce the desired outcome.

Second because we need to give confidence and demonstrate our own trust in the proposed solution. No audience would be thrilled hearing that this solution “may”, “should” or “could” produce the desired result. No decision maker would give his/her go for a change program or a solution implementation which is not certain to produce the expected result.

The use of conditional / tentative language would only raise concern about the feasibility of the proposed solution and appear as a lack of confidence of its promoters.

Wrapping up

Tentative language is recommended in academic writing, not at all with logic trees.

Using tentative language is recommended in academic writing and scientific research in order to leave room for alternatives, later corrections, etc. unless there is solid evidence backing up a statement. Therefore the use of verbs like “appear, suggest, indicate,…”, modals “may, might, can, could, will, would” and adverbs like “possibly, probably, likely…” are recommended.

But when building or presenting logic trees, absolute certainty is required in order to demonstrate robustness of the analysis and the confidence in the conclusions. If a logic tree is built on the canonical logic rules (we’ll consider the use of present tense as a canonical logic rule), has been scrutinized and cleared of all reservations, it is robust and tentative language is no option.

The author, Chris HOHMANN

The author, Chris HOHMANN

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The Logical Thinking Process – An Executive Summary (Book)

Bill Dettmer, my friend and mentor often cited on this blog, wrote his 9th book “The Logical Thinking Process – An Executive Summary” that is now in the final stages of the publishing process.

This book will be much smaller in size and number of pages than the famous “The Logical Thinking Process: A Systems Approach to Complex Problem Solving”. The latter is a 413 pages, 17,1 x 3,2 x 24,1 cm (6.8 x 1.2 x 9.5 inches) hardcover book. Bill Dettmer’s students use to call it “The Bible”. It is a complete step-by-step guide, easy to read and understand, but not everybody can invest the time required to read it just to get a primer on the Logical Thinking Process.

That’s where the “Executive Summary” comes in handy. Bill himself stated: “Over the years, I’ve found myself having to explain what the Logical Thinking Process is in 30 seconds or so to people who have never heard of it – or know nothing about it if they have. I came to the conclusion that while the LTP is difficult, if not impossible, to encapsulate in an “elevator speech,” it might be somewhat easier to do in a pocket-sized book.

I was fortunate to be selected by Bill as a kind of sounding board and proofreader, even so Bill did so more out of kindness than necessity, and had a privileged first reading. The book will serve its purpose, I think it can be read during a short business trip on a plane or a train. The final copy should be less than 100 pages.

As soon as I’ll get a copy, I will complete this post with an extended review of the book.

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The downsides of customer satisfaction surveys

Customer satisfaction is the holy grail every company is looking for. In the desperate search to please their customers they multiply polls and inquiries in order to get the important insights first hand. Doing so, they overlook a possible serious “negative branch” * bothering the customers they so desperately want to please.

*a negative branch is an unexpected negative effect  or series of effects triggered by an action or decision. You may want to learn more about What is Negative Branch Reservation?

You have probably experienced this a number of times. As soon as you interacted or bought something from a company, a customer satisfaction questionnaire shows up.

I recently spent a night in a hotel affiliated to a hotel group. The very next day I got two e-mails, the first advertising the members program the second to get my opinion about my stay. I happen to speak to the hotel manager and owner directly, and share my (positive) opinion about his hotel and the nearby restaurant. My direct feedback with specific examples is probably more profitable for the owner than adding my answers to the standardized corporate statistical analytics.

These customer satisfaction inquiries, even so I perfectly know their purpose and importance, they are a bit too numerous and sometimes somewhat too aggressive.

There was this purchase on-line for which I got an invitation to assess the website friendliness right after, and the list goes on.

I happen to change the tires of my (so-called “premium brand”) car before winter and have them exchanged again beginning of spring. Before I even left the garage, I had an e-mail on my smartphone inviting me to assess the service. Of course, the very same inquiry came in a few months later when tires were changed again.

Sure, it is important to insure consistency, thus to regular check of the ongoing customer satisfaction, but do people planning these inquiries imagine how, passed a certain number of such “invitations” they s*ck?

It is nothing new as my check on my favorite internet search engine confirmed. Despite the evidence most of these surveys are just an annoyance, they keep arriving.

This post is useless, but is my way to get rid of the bad temper.

Now, if you’d be so kind and answer my survey…

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30 elements of value, entrepreneur’s food for thoughts

What is value? What is a customer willing to pay? Since Lean Thinking and Lean principles are around, many organizations strive to bring more value to the customer. But apart from reducing costs what levers do they have to bring more value to theirs customers?

The article titled “The Elements of Value” published in the HBR september 2016 issue by Eric Almquist, John Senior and Nicolas Bloch, brings no less than 30 answers to these questions.

I strongly recommend to read the article. The online issue can be read here: https://hbr.org/2016/09/the-elements-of-value

In this post I summarize the very minimum about the 30 elements of value and share some of my thoughts about them.

30 elements of value

The authors, all three working for Bain & Company’s, have identified 30 “elements of value”, which are “fundamental attributes in their most essential and discrete forms”, that meet fundamental human needs. They classified these 30 elements into 4 categories stacked on a Maslow’s “hierarchy of needs” inspired pyramid to organize the elements of value according to their relative “power”:

  • functional,
  • emotional,
  • life changing,
  • social impact.


Similarly to the popular assumption that (in Maslow’s model) people cannot attain the needs at the top until they have met the ones below, to be able to deliver on higher-order elements, a company must provide at least some of the functional elements required by a particular product category. But many combinations of elements exist in successful products and services today.

A comprehensive cheat sheet for entrepreneurs

I really liked the way the authors presented their findings and I thought this is a nice comprehensive cheat sheet for entrepreneurs, startupers, managers, and for everyone seeking to enrich their value proposition.

What can I do to relieve the pain of my customer? How to bring her some gain? How can I extend our offering? Have a look on the 30 elements and check if the answer to these questions isn’t among them.

The HBR article gives some examples among which Amazon prime. It describes how the service went from its initial shipping offering for $79 annual fee to an extended offer at $99 within 10 years, while conquering significant market share of the U.S. retail market.

I think the 30 elements may find their way into the graphic toolbox started by Strategizer with the Business Model Canvas and the Value Proposition Canvas, as a checklist, a cheat sheet, or seeds for creative brainstorming.

Entrepreneurship is not only for the startupers. Those wanting to reinvent or reinvigorate their business, those who want to keep competitors at a distance or those worrying about a possible business disruption may wisely invest some of their time reflecting on the 30 elements of value as well.

There is probably more value in the article than what I report here. Feel free to share your thoughts in the comments.

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About the author, Chris HOHMANN

About the author, Chris HOHMANN

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