Latest / Mechanical Engineering Made Simple / (#29) Lean Manufacturing Exposed: Jidoka, JIT, and the Cultural Science of Waste Elimination (Takt Time, OEE, and the Toyota System)

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(#29) Lean Manufacturing Exposed: Jidoka, JIT, and the Cultural Science of Waste Elimination (Takt Time, OEE, and the Toyota System) · Mechanical Engineering Made Simple

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  Get ready to torque your nuts, harden your springs, and forge
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  your mind into a bulletproof study guide.
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  We are Mechanical engineering Made Simple welcome you to the
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  deep dive on a philosophy that well fundamentally changed how
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  the world manufacturers everything Lean manufacturing
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  and the legendary Toyota Production System or TPS.
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  Yeah, and it's really more than just, you know, an efficiency
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  Dr. This is a truly revolutionary engineering
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  approach. It came from Tai Chi Ono, and
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  it's deeply rooted in precise measurement and just this
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  relentless focus on delivering actual value.
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  It's really a total rejection of those old clumsy mass production
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  methods. Right, the high inventory
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  functional silos way of doing things.
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  So our mission today is basically to give you the
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  shortcut. We're going to breakdown the
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  core concepts here. You know, the structural
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  pillars, the key engineering metrics, and also the deep,
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  often ignored cultural stuff. The cultural requirements.
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  Yeah, the things you absolutely need to transform a plant into a
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  highly flexible, responsive system.
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  Basically, we're learning the science of waste elimination.
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  And when it's implemented properly, the results are, well,
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  they're dramatic. That's why we're diving in.
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  The ultimate goal here, it's achieving huge resource savings.
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  We're talking things like half the human effort on the factory
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  floor. Half Wow.
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  Yeah, half the floor space needed, half the investment in
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  tooling and crucially, way less than half the inventory.
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  And all that while delivering fewer defects to the customer.
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  So quite something. Let's unpack this.
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  Then let's start where Ono started.
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  The absolute elimination of waste.
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  The Japanese term is muda, right?
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  That's it, Muda. So what exactly qualifies as
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  muda in the TPS context? OK, so MUDA or waste, it's
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  defined as basically anything that prevents the value added
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  flow of material, you know, from goods all the way to the
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  finished product. But the most critical part of
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  this definition really is that the customer is a final judge.
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  They decide if value has actually been created.
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  That customer focus changes everything for engineering
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  goals. So how do we figure out what's
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  true value add? You mentioned 2 criteria.
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  Yeah 2 non negotiable criteria and activity only adds value if
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  it meets both. OK, first it has to physically
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  add to the form fit or function of the product itself.
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  Makes sense. 2nd, and this is the key, it has to be something
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  the customer is actually willing to pay for.
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  Willing to pay for OK, that distinction really does turn
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  traditional thinking on its head.
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  So things like transportation priced inspection waste.
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  OK, but hold on, I have to push back a little here.
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  Sure, If I don't transport a part, it never gets to the
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  assembly line, right? And if I ship, say, complex
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  engine parts without careful packaging, they'll arrive
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  damaged. So isn't that protection kind of
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  necessary? Isn't it value added in a way?
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  Ah. You've hit the nail on the head
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  there. That lets us distinguish between
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  pure waste and what we sometimes call necessary waste.
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  True lean thinking actually categorizes all non value added
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  activities, even the necessary ones like protection and
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  transport. As Mudo OK, the goal isn't just
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  to get rid of the obvious pure waste, it's also to relentlessly
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  minimize that necessary waste too.
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  OK, that makes more sense. So the customer doesn't care
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  that the material traveled, you know, 25,000 miles through 4
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  suppliers exactly or about the three different types of
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  internal packaging used. They just care about getting
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  good value for their money. Precisely.
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  And that relentless external focus on what the customer
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  values, that's what drives lean manufacturing.
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  That's what pushes the efficiency games through
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  teamwork, open communications, smart resource use, and that
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  idea of continuous improvement Kaizen.
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  Right, Kaizen. So if value is the goal, we need
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  the engineering structures to actually enforce it.
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  And that brings us to those famous twin pillars of TPSJIT
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  and judoka. We hear a lot about JIT just in
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  time, but let's start with the Joker.
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  That's the one engineers often find a bit counterintuitive.
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  Like judoka, it's often translated as autonomation, or
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  maybe automation with a human touch.
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  It's really centered on using machines and people effectively
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  together. But its core principle, the
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  absolute directive, is this. No defective parts should ever
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  be allowed to advance in the production system.
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  OK. No defects forward.
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  And that leads to the famous or maybe infamous Judoka paradox
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  shutting down the entire line. Yes, why on earth is stopping
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  production the smartest move? I mean, every traditional
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  incentive screams keep the machines running no matter.
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  What? Because judoka operates on this
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  really profound principle, right?
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  Quality is production. They're equal.
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  If a defect happens, the line has to stop immediately.
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  Often it's an operator pulling an and on cord the.
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  And on cord. Right, and it stays stopped
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  until the root cause is found and completely eliminated.
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  So the paradox is clear. You shut down the system
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  temporarily so the system can actually run continuously and
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  predictably over the long haul. If you let bad parts move
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  forward, you just contaminate everything downstream.
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  That leads to massive, hidden, really expensive rework later
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  on. So judoka creates this
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  unshakable quality foundation you mentioned, Oneo the sources
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  say he stressed they spent 7 focused years building that
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  quality control foundation. Yes, seven years before they
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  really embarked on quantity control.
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  That level of patience it seems almost impossible today.
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  It does, doesn't it? Seven years sounds like an
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  eternity in modern business, but that cultural requirements
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  stopping the line immediate root cause analysis.
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  It has to be deeply institutionalized before you
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  start trying to speed up the flow.
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  TPS fundamentally it's a system of quantity control.
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  That's JIT, but it's built entirely on top of a high
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  quality foundation. That's Judoka.
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  OK, let's talk about that quantity control then.
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  JIT making what is needed only when it is needed.
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  What are the key tools that enable that pulse system?
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  You know, getting away from wasteful push scheduling well.
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  The primary tools Kanban. It's really revolutionary.
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  It's the practice of using physical cards or sometimes
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  other visual signals. Like lights or empty bins.
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  Exactly. Visual signals to smooth out the
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  flow and create a demand driven pulse system.
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  It triggers replenishment directly from consumption right
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  at the next process step. It controls inventory, minimizes
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  that huge waste of overproduction, and make sure
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  flow is tied directly to actual customer withdrawal.
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  OK, can man for poll and the other key tool, the one that
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  attacks the old assumption that you have to run huge batches to
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  be efficient SMED. SMED Single Minute Exchange of
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  dyes developed by the brilliant Shiger Shingo.
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  SMED is basically a batch destruction technique.
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  Its whole focus is slashing changeover times, ideally down
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  to a single digit number of minutes.
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  Single digit minutes for a major machine changeover.
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  That's the goal. By drastically reducing change
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  over time, you drastically reduce the economic batch size.
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  Smaller batches mean less waste in two key ways.
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  Less excess capitalization tied up in tooling right, and less of
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  that massive overproduction you need just to build buffer stock
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  during those long changeovers. This directly enables JIT and
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  dramatically cuts lead times. OK, so we have the philosophy,
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  eliminate waste. We have the pillars, judoka for
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  quality, JIT for quantity, enabled by tools like CON, Ban
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  and SMAD. But how do we actually know if
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  it's working? How do we measure success?
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  That brings us to the engineering metrics.
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  Let's start with the heartbeat of the line, tact time.
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  Right talk time talked is the the design process cycle time
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  you need to exactly match the customer's demand rate, but it's
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  normalized to your actual roduction schedule.
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  It sets the absolute pace and we calculate it using a pretty
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  simple ratio. It's available work time divided
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  by customer demand. So dollars available work time
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  slash customer demand dollars. OK, let's walk through a quick
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  example. Maybe conceptually so it's
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  easier to follow without complex math on audio.
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  Good idea. Let's imagine a plant needs to
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  produce say 500,000 units per year.
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  OK, Now based on your actual operating schedule, maybe 2
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  shifts 5 days a week, minus holidays, breaks, planned
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  downtime, you figure out your total available work time for
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  the year in minutes or seconds. Right, the actual time you can
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  produce. Exactly.
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  So you take that total available time and you divide it by the
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  500,000 units the customer wants.
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  Let's say that calculation comes out to approximately 0.56
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  minutes. 0.56 minutes. That's about 34 seconds.
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  Right, about 34 seconds. So what does that 34 seconds
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  actually mean for the engineers and the managers on the floor?
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  It means that if you want to stay perfectly in step with
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  customer demand without building up wasteful inventory or falling
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  behind, you must produce 1 good saleable unit every 74 seconds.
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  So it's a hard target. It's a hard target set by the
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  customer. Essentially, if your current
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  production cycle time for one unit is longer than 34 seconds,
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  you get an engineering problem to solve.
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  You won't keep up. And if it's much shorter?
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  If your cycle time is, say, 20 seconds, you're going to build
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  inventory like crazy expensive, unnecessary inventory.
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  Tac time defines the rhythm. OK, TAC time sets the rhythm.
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  Beyond that, what else measures the ultimate health of the whole
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  process flow? What's the big picture metric?
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  Lead time reduction. Tai Chiona always, always
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  hammered this, he said. The key metric is, and I'm
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  paraphrasing slightly, looking at the timeline from the moment
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  the customer gives us an order to the point when we collect the
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  cash. Order to cash.
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  Order to cash and we are reducing that timeline by
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  removing the non value added wastes.
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  Short lead times, he argued, are the true guarantee of
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  flexibility, good quality and stable processes.
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  Makes sense. Faster flow means less chance
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  for things to go wrong, less inventory sitting around.
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  And finally, there's the big diagnostic tool for equipment
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  performance. OEE, overall equipment
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  effectiveness. Yes, OEE is crucial.
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  It gives US1 clear number for overall production effectiveness
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  combining 3 factors. The equation is dollars OEE
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  equals A * Q * P dollars. OK, break that down, AQP.
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  Right. So A is availability, is the
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  machine running when it's supposed to be running, Q is
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  quality yield, how many good parts are we making versus total
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  parts started? And P is performance.
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  How close is the machine running to its design cycle time or to
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  tack time? So if your OEEE is low, where do
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  you look first? Well, if your availability the A
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  is low, that often points to serious instability.
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  Machine breakdowns, long changeovers basically and cringe
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  and problems needing judoka solutions.
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  Cycle time losses, the performance factor, P not
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  meeting the tact rate. That's often the low hanging
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  fruit. Engineers can attack 1st to get
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  through put up quickly, maybe through SMND or work balancing.
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  And the tool used to actually see all this, to visualize the
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  entire system before you start changing things.
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  Value stream mapping VSM. VSM is absolutely the first step
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  in any successful lean transformation.
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  You have to do it. It charts every single
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  literally, from raw materials coming in the door to the final
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  customer delivery. And its specific purpose is to
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  expose those huge amounts of hidden waste, unnecessary steps,
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  delays, excess scrap, inventory, mountains.
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  How's it different from just a regular process flow chart?
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  Good question. A simple flow chart just shows
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  the steps. VSM visualizes the entire system
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  including information flow, inventory levels, cycle times,
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  lead times. It shows the why you need to
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  improve the overall system performance rather than just
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  letting you optimize little isolated pieces of the process.
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  It forces a system view. OK.
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  We've covered the engineering tools, the metrics, tact, lead
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  time, O EE, VSM, we've got Judoka, JIT, Conaban, SMED.
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  But the sources and you hinted at this make it crystal clear.
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  The tools, that's the easy part. The really difficult part is the
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  culture. Absolutely.
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  Why does management so often fail here?
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  Why do they fail to institutionalized the change
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  leading to that quick regression after some initial success?
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  It often comes down to what's called the quick fix mentality.
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  Management sees those massive low hanging fruit gains early
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  on. Yeah, the easy wins.
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  Exactly simple things, maybe cleaning U workstations with 5S,
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  maybe some minor mad imrovements.
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  They get excited by the initial jum in metrics right?
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  But then they failed to institutionalized the deeper,
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  harder cultural changes. They stopped doing the really
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  difficult work, the system thinking the daily Kaizen.
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  And that leads predictably backsliding regression.
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  It takes time. It takes years.
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  Ono himself spent over 30 years owning the TPS culture at
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  Toyota. So expecting a complete
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  sustainable transformation in say, 18 months, it's just not
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  reasonable. It takes sustained effort and
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  leadership commitment. So what are the key
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  non-technical shifts? The cultural changes needed to
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  fight that regression and make Lean actually stick.
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  Well, the most fundamental 1 I think goes right back to judoka.
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  It's creating a no blame environment.
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  No blame. Explain that.
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  Think about it. If you ask an operator on the
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  line to pull that octolin cord to stop production because they
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  see a defect and they know that stopping the line is going to
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  result in them getting yelled at, maybe discipline punished
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  for disrupting the flow, what are they going to do?
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  Hide the defect, pass it on. Exactly.
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  They'll hide it. So the entire engineering goal
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  of judoka, instant fault detection and correction,
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  becomes completely impossible without that cultural foundation
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  of no blame. So the focus has to shift.
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  Entirely from fault finding pointing fingers at people to
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  fact finding pointing fingers only at the processes.
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  Mistakes aren't reasons for punishment, they're seen as
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  golden opportunities to learn and make the process itself more
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  robust. That's a.
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  Huge shift for many traditional management styles.
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  Huge Another hurdle is fighting simplistic thinking, especially
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  at the executive level. What do you mean by simplistic
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  thinking? Well, executive teams.
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  They often get energized by those simplified success
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  stories. They read about case studies
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  that conveniently ignore all the bumps and bruises, the political
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  fights, the setbacks involved in real cultural change.
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  They want to believe transformation is just a simple
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  linear project plan. But any profound change journey
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  involves complications. It involves confronting
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  entrenched thinking, maybe taking a few wrong turns.
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  That's messy. Cultural development is messy.
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  It requires acknowledging that, embracing the learning that
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  comes from the mass, and having the patience to work through it.
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  OK, let's touch on standard work.
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  To an operators, standard work can often feel like just more
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  management paperwork, something that restricts their autonomy.
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  How does it fit into this positive cultural shift?
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  Yeah, standard work is probably one of the most misunderstood
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  lean tools, especially in western imlementations.
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  Yes, OK, it is a tool for management and auditors to
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  ensure consistency, but that's not its primary purpose.
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  In a true lean culture, its primary purpose is actually to
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  enable Canizon continuous improvement.
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  Standard work is simply the documentation of the current
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  best known way to do the job safely, efficiently and with
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  high quality. Right now it establishes the
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  necessary baseline. So instead of being restrictive,
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  it's actually the starting point for challenging the process.
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  Precisely. You cannot systematically
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  improve a process if you don't have a clear, agreed upon
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  understanding of the current state.
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  Standard work provides that baseline.
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  It ensures we consistently do what's been shown to be
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  effective. And by having it documented
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  visually right at the workstation, you give the team a
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  concrete structure they can measure against, analyze, and
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  then challenge to find an even better.
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  Way and transparency is key there.
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  Absolutely. Using visual controls like those
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  high junker boards for leveling production or the and on lights
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  allows managers, team leaders, everyone to audit the work
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  quickly to see if the process is running as designed in just a
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  minute or two. That enables immediate feedback
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  and those rapid response PDCA cycles.
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  Plan, do, check, act. It really is abundantly clear,
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  then, lean engineering isn't just about the tools and
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  techniques, it's a deep systems thinking challenge.
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  It involves psychology, sociology just as much as it
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  involves hydraulics or mechanics.
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  Great way to put. It the technical applications,
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  you know, TAC time, SMDO, EE, they're profound, but it's the
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  behavioral changes required that no blame culture, the discipline
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  to actually stop the line when needed.
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  That's what really separates the truly successful lean operations
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  from the, well, the imitators. Indeed.
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  And maybe a final thought to lead people with Remember the
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  biggest waste of all, the one that often hides or enables all
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  the other inefficiencies, It's inventory.
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  Right inventory covers up problems.
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  It does, but here's the twist. While inventory is definitely a
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  waste, it's often also a necessary response to system
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  variation just so you can maintain the required production
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  rate. Therefore, if you really want to
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  reduce inventory, and you should, you can't just decree
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  cut stock levels. You have to 1st eliminate the
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  underlying variation that makes the inventory necessary.
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  So attack the root cause, not the symptom.
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  Exactly. You can't solve an inventory
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  problem by just cutting stock. You have to attack the real
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  enemy. System variation, whether that's
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  machine downtime, quality defects, supplier issues,
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  whatever it is causing the instability.
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  A powerful final point. Attack variation first until the
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  next equation. Design junkies.
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  We are mechanical engineering made simple.
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  Stay balanced, stay precise, and never stop building.