So sánh lean manufacturing và tps năm 2024

Over the length of my career I have used the Toyota Production System and Lean as interchangeable terms that meant the same thing essentially... but not really. More and more I dove into the finer intricacies of the Taiichi Ohno's masterpiece "Toyota Production System: Beyond Large Scale Production" more and more I realized that the the two might seem similar on the surface but what lies beneath is completely different.

One of the first things that people think about Toyota Production System is "well, it's a Toyota Production System so you can only do it at Toyota". Nothing can be further from the truth. Just like Windows or MacOS is the Operating System of your computer, and Android/iOS are the operating systems of your phones, they enable these devices to perform complex tasks to our needs. Toyota Production System (TPS) does a very similar thing, it is the operating system of a business that can be implemented from the smallest of scales to the largest of enterprises to suit any need, and we have a blueprint in Toyota to use as a guide to successful implementation if we get stuck.

Another place where TPS starts to diverge from Lean is that TPS is a philosophical and cultural shift where Lean is a tool based approach. Even the smallest thing such as the waste chart can tell you quite a bit about this, TPS has 7 wastes and Lean has 8 wastes. WHY? Let's dive into that a little bit.

TPS is founded philosophically on 4 basic tenants:

1. Customer First (Do not accept, create or pass on defects)
2. People are the most important resource (they are the only resource that can problem solve)
3. Kaizen (Continuously improving to True North)
4. Genchi Genbutsu (Shop Floor Focus where production actually takes place)

Lean on the other hand has no philosophical foundation what so ever and if you asked 10 different people what Lean was you'd get 15 different answers of what Lean was or what it meant "to be a Lean organization". This is why the 8th waste, the waste of the human talent, had to be put in the Lean wastes. There were no philosophies to state we should respect people and utilize their time and talents the best. One thing I find interesting though is when I ask the executives "WHY ARE THE PEOPLE OUR MOST VALUABLE RESOURCE?" no one knows. Toyota is quite clear on this. Machines are great at repetitive tasks but people are outstanding problem-solvers. Repetitive tasks in people induce boredom but when we are given a problem, our creativeness hits new levels and we are invigorated. Not just that but having the True North as a guiding principle TPS is making sure that we have strategy guide our decisions where Lean tends to provide short term gains but truly lacks long term benefits when the data is parsed through. (I'd be more than happy to elaborate on this 1-on-1 of needed)

Another place where TPS and Lean differ is defining of their purpose. When you ask people what Lean is about almost everyone will tell you that Lean is about eliminating waste. TPS is not. What is then TPS about? TPS is about highlighting problems, so that we can solve them, so that we can do more with less. Isn't that the same thing? Absolutely not, mostly because of how one interprets and defines waste. Is being overstaffed a waste? I say it is not, I say that is having additional capacity to provide new product lines to customers, tap into new markets, or complete new improvement projects that we haven't had time to complete in the past. Or maybe we just don't hire as many people in the future and wait for the attrition to take care of the imbalance while we take this opportunity to cross train people and capture the knowledge of the experienced workers that is about to leave our doors forever.

There are many other differences but the final one, and one that I think is the most important one is the difference in the approach. Lean in general is a toolbox approach. Most "Lean Practitioners" will throw out terms like "you have to build to Takt to meet customer demand", "5S for success", "Value Stream Mapping is really important", "Kaizen events are the only way to do Lean successfully", "WIP/inventory is bad, have to get rid of it". I will admit, for a short period of time in my career I was a part of this system and after about 2 years of trying it this way I realized that not only is it ineffective but it has a completely adverse and opposite impact on the workforce than intended. Like I mentioned before, TPS is a philosophical and cultural shift in the way we think and the way we approach things in general. TPS is a systematic approach to satisfying customer needs. It is not one thing and you can't do things out of sequence, the path is well defined all one has to do is follow it. What do I mean by that? You can't go into an area and immediately revamp it into a "Lean" production machine that will increase throughput and have excellent results, especially not long term. So the "workshop" approach, as many have already experienced, gives a burst of short term gains and then quickly fades after several months as if it never happened. After a while people develop a negative feeling toward the events and they start thinking "Oh here we go again, they are going to tell us how we're going to do our jobs again" and they realize that all they have to do is stick it out longer than the "flavor of the month" and things will go back to the way they were before. The statements I quoted up there are the ones I have heard made many times and I disagree with wholeheartedly.

• One can meet customer demand without producing to takt, businesses have done it many times in the past. It's OK to batch. Yes, I've said it. If you know you're not capable of producing in a continuous flow, 1x1, takt based line then batching is absolutely fine. Know your limitations and stick with your strengths. The goal is to to produce 1x1 in sequence to the customer demand in a process designed with no waste but that is a goal, so long as we have a plan and a path forward then batch away my friend.Not just that but to this day Toyota batches certain processes because the technology is not there to enable 1x1 flow. So some places it's just not possible. Or throw more people at it for now, we have to make deliveries. That is the most important thing and trying to force a concept before a business or an area is ready is a sure way to lose the trust of the people that work there.
• I don't even know where to start with 5S. I remember reading an old interview with Taiichi Ohno about 5S and he laughed at it and said you have to do 5S when you can't do TPS. Essentially, what he said is that Toyota doesn't do 5S because that's covered by all other things that Toyota does. Just In Time, Standardized Work, Respect For People, TPM, Visual Factory, etc. So if you do all of those things correctly, you really don't have a need for a 5S program, everything is already there.
• Value Stream Mapping is probably the second most wasteful thing I've done in my career. Yes, the information can be very valuable and I've actually used the Current Condition, Target Condition, and Future Condition exercises to help create a long term business strategy with the leadership but for mapping a value stream, a 20 minute Material and Information Flow Map by walking the production from end to start 2-3 times will suffice 99.99% of the time. Tying up valuable shop floor and management resources in a room for 3 days while they are pulled out of it half the time is pointless to be honest.
• Kaizen events ARE THE MOST WASTEFUL THING I've done in my entire career. Just think about it, and seriously just sit down and think about this from your own personal experience. For one week you lock a group of people in a room and tell them here's a problem and we need you to find a solution. OK, awesome! So that's 5 M days. We have 10 people in there? Usually a Quality person, Supervisor, Engineer, area lead, couple of top performers in the area, couple of people outside of the area and one person from a customer process and another person from the supplier process. So right there you've just crippled the area that is already having problems by removing the supervisor, the lead and the best performers. For that week they are not getting anything done and you know it. For those 5 M days, just the labor in that room is about $15K including benefits and everything, plus the impact to production and the OT you'll have to work to make up the fact that the you didn't get anything done on the shop floor for that week. I didn't even mention that consultant fees involved in that debacle yet, or the fact that they will have to come back to help "implement" the solution. So this one week event can cost a production facility an easy $50K after everything is said and done and that is not counting long term impacts of the rest of the cell saying "Oh, these guys went into the room and now they will tell us how this will make our jobs better? Yeah right!" To this date I have not come across an organization that has successfully implemented the "Kaizen Event" model long term.
• So, inventory is not bad. Uncontrolled inventory is bad, controlled inventory is good because it protects you from the impacts of problems until you can solve them. If you have a consistent quality failure of 20% at a certain process, the only way to protect deliveries down the line is to have an inventory buffer at the next process and a robust rework loop to bring parts back into production. The only way to eliminate that inventory is to eliminate that problem which is causing the defects. If you eliminate the inventory before the problem, you're going to miss deliveries that is for certain. So this whole "inventory is bad" thing is a fallacy that just shows me that people don't understand how to properly manage inventory to their advantage. We need to solve problems and high inventory levels in an area should be a sign of big problems which means that is where our best and brightest minds should be going first to help us solve those problems. I agree that having too much inventory is a bad thing but eliminating inventory before we area ready can lead to a disaster worse than having it there to begin with.

Just like everything in life, we all have our opinions and in this article I am expressing mine... quite strongly I might add. But I also believe, quite strongly, in the principles of TPS because I've used them countless times to help businesses grow and achieve things they never thought possible. I've worked with businesses who, for decades, tried to do it the "Lean Way" and then after implementing even a small fraction of TPS they were astonished by the results they were able to achieve. More importantly it wasn't only the financial results that they saw the benefits in, their employees were happier, more engaged, and the retention rates grew as the system took hold. Don't be fooled though, while TPS is a very simple system in theory, and it truly is, the implementation of the system is quite difficult and complex.