It would also be useful if you could have students develop a similar list for services.
Students should be asked to draw their own connection between inventory and problems. Given that inventory exists in case of problems, if we wish to eliminate inventory, we also must eliminate problems. Again the notion that JIT is not simply an inventory methodology.
In discussing this slide, it is helpful to stress the caveat that JIT works given that other problems are solved. JIT not only requires the solution of other problems, it also helps in diagnosis.
The analogy presented in this and the next four slides may help to illustrate the action of inventory in hiding problems.
The next several slides look at the process and consequences of reducing inventory.
Tps and lean manufacturing
Toyota Production System (TPS),
and Lean Manufacturing
Muhammad Adeel Javaid
TPS Practitioner and Consultant
History• Sakichi Toyoda, the founder of the Toyota group of
companies, started Toyota as a textile machine
• Kiichiro Toyoda, son of Sakichi and founder of the
Toyota automobile business, developed the concept
of Just-in-Time in the 1930s. He decreed that Toyota
operations would contain no excess inventory and
that Toyota would strive to work in partnership with
suppliers to level production.
• Taiichi Ohno, Toyota's chief of production in the post-
WWII period. He was THE main developer of Toyota
Production System (TPS).
• Dr. Shigeo Shingo: A consultant to Toyota.
PS: Shingo Prize is the highest manufacturing
excellence award in the U.S. The prize is given both
to companies and individuals who contribute to the
• Toyota Production System (TPS) drew wide attention from the industrial
community because Toyota was a profitable car company in Japan
during and after the oil embargo in 1970s.
• Outside Japan, dissemination began in earnest with the creation of the
Toyota-General Motors joint venture-NUMMI (New United Motor
Manufacturing Inc.) in California in 1984.
• Widespread recognition of TPS as the model production system grew
rapidly with the publication in 1990 of The Machine That Changed the
World: The Story of Lean Production, the result of five years of
research led by the Massachusetts Institute of Technology.
• The MIT researchers found that TPS was so much more effective and
efficient than traditional, mass production that it represented a
completely new paradigm and coined the term lean production to
indicate this radically different approach to production.
• The term was coined by John Krafcik, a research assistant at MIT with
the International Motor Vehicle Program in the late 1980s. He then
worked for General Motors and now is a Vice President of Hyundai,
Toyota Production System (TPS)
• Definition: The production system developed by Toyota
Motor Corporation to provide best quality, lowest cost, and
shortest lead time through the elimination of waste.
• TPS is comprised of two pillars, Just-in-Time and Jidoka
(autonomation) , and is often illustrated with the "house"
shown on the next slide.
• TPS is maintained and improved through iterations of
standardized work and kaizen (continuous improvement),
following Plan–Do-Check-Act (PDCA Cycle from Dr.
Deming), or the scientific method.
Toyota Production System (TPS):
• Ohno System
• MAN (Material as Needed) - Harley
• MIPS (Minimum Inventory Production
Systems) - Westinghouse
• Stockless production - Hewlett Packard
• Zero inventory production system
• Lean Manufacturing/Production - MIT
How to make money?
Profit equation: Sales – Cost = Profit
Traditional pricing strategy: Cost + Profit = Selling price
When the cost goes up, the product selling price is raised to
reflect the higher costs and maintain the desired level of
Some even argues that the profit added should be large
enough to cover potential losses if the product does not
Toyota accepts neither this formula nor these arguments!
• Selling price – Cost = Profit
• Customers decide the selling price.
• Profit is what remains after subtracting the cost from it.
• The main way to increase profit is to reduce cost.
• Consequently, cost reduction through waste elimination
should have the highest priority.
• Toyota’s paradox: Reducing cost (waste), will reduce lead
time while increasing quality and customer satisfaction.
• How? We will discuss it soon.
• Attacks waste
– Anything not adding value to the product
• From the customer’s perspective
• Exposes problems and bottlenecks caused by
– Deviation from optimum
• Achieves streamlined production
– By reducing inventory
What Does Just-in-Time Do?
Variability Occurs Because
• Employees, machines, and suppliers
produce units that do not conform to
standards, are late, or are not the proper
• Engineering drawings or specifications are
• Production personnel try to produce before
drawings or specifications are complete
• Customer demands are unknown
• Producing and moving one item at a time (or a
small and consistent batch of items) through a
series of processing steps as continuously as
possible, with each step making just what is
requested by the next step.
It is also called the one-piece flow, single-piece
flow, and make one, move one.
Continuous Flow Production
Flow with JIT
(stream of water)
Push versus Pull
• Push system: material is pushed into
downstream workstations regardless of
whether resources are available
• Pull system: material is pulled to a
workstation just as it is needed
Traditional U.S. Manufacturing Firm:
Push (“old style” MRP / Material
Requirements Planning System)
• The production of items at times required
by a given schedule planned in advance
Information (Production Schedule)
WS 2 WS 3
Pull (JIT) System
The production of items only as demanded for
use or to replace those taken for use.
Information (via Kanban/Card)
WS 2 WS 3
• Japanese word for card
– Pronounced ‘kahn-bahn’ (not ‘can-ban’)
• Authorizes production from downstream
– ‘Pulls’ material through plant
• May be a card, flag, verbal signal etc.
• Used often with fixed-size containers
– Add or remove containers to change production
Trigger (Reorder) Point
Part Description Location
Date Triggered Lot Size
Basic Fixed-Order Quantity Model and
Reorder Point Behavior
R = Reorder point
Q = Economic order quantity
L = Lead time
1. You receive an order quantity Q.
2. Your start using
them up over time. 3. When you reach down to
a level of inventory of R,
you place your next Q
4. The cycle then repeats.
The function of Kanban ≈
The function of Inventory Reorder Point
• Single card
– Move only containers
with C (Conveyance)-
– e.g.: Kawasaki
• Dual card
– Move only container
with C- kanban
– Produce only when
authorized by P
– e.g.: Toyota
• Traditional: inventory exists in case problems
• JIT objective: Eliminate inventory
• JIT requires
– Small lot sizes
– Low setup time
– Containers for fixed number of parts
• JIT inventory: Minimum inventory to keep
• Reduce ripple effect of small variations in
schedules (e.g., final assembly)
• Production quantities evenly distributed over
time (e.g., 7/day)
• Build same mix of products every day
– Results in many small lots
– 1 month = 20 working days
– Item Monthly Quantity Daily Quantity
A 40 2
B 60 3
Heijunka = Leveling (Smoothing) Production
Schedule using Mixed Model Sequencing
A A B B B C
JIT Small Lots
A A B B B C
A A A B B B B B B C C
JIT produces same amount
in same time if setup times
Small versus Large Lots
Small lots also increase flexibility to meet
40 10 4
40 10 4
10 10 1
Heijunka = Leveling (Smoothing) Production Schedule using
Mixed Model Sequencing = Uniform Plant Loading
Product Demand Requirements
800 20 40
800 20 40
200 20 10
Largest integer that divides into all daily requirements evenly is 10
Product Daily Requirements Divided by 10
A-B-A-B-A-B-A-B-C Repeat 10 times per day
Determining Production Sequence
Working time per day = 480 minutes
Daily requirements: A = 40 units; B = 40 units; C = 10 units
The system cycle time = 480/(40+40+10) = 5.33 min/unit
Product Requirements Cycle Time
480 40 12
480 40 12
480 10 48
Work in process inventory level
Unreliable Vendors Capacity Imbalances
Reducing inventory reveals
problems so they can be solved.
Unreliable Vendors Capacity Imbalances
Reducing inventory reveals
problems so they can be solved.
Unreliable Vendors Capacity ImbalancesWIP
Lot size = 5
Lot 1 Lot 2
Lot size = 2
Lot 1 Lot 2 Lot 3 Lot 4 Lot 5
Reducing Lot Sizes Increases the
Number of Lots
Unless Setup Costs are Reduced
Holding CostTotal Cost
New optimal lot size
Quick setup = Quick changeover
• Reducing setup cost ≈ reducing setup time
• Setup reduction time is a prerequisite to lot size
• SMED (Single Minute Exchange of Dies)
• The method has been developed by Toyota and
then expanded by Dr. Shigeo Shingo (a
consultant to Toyota), and has proven its
effectiveness in many companies by reducing
changeover times (non-value added times) from
hours to a less than 10 minutes
• Internal Setup: consists of setup activities that must
be performed while the machine is stopped.
• External Setup: consists of setup activities that can
be carried out while the machine is still
It is desirable to:
1. Convert as much internal setup to external setup
2. Improve the setup procedure
Quality At The Source
• Doing it right at the first time.
• Jidoka allows workers to stop production
• Andon lights signal quality problems
• Under capacity scheduling allows for
planning, problem solving & maintenance
• Visual control makes problems visible
• Poka-yoke prevents defects
• Toyota Production System (TPS) is supported by two pillars: Just-in-
Time and Jidoka
• Jidoka = Autonomation = Automation with “human” intelligence.
• Sakichi Toyoda, founder of the Toyota group of companies, invented
the concept of Jidoka in the early 20th Century by incorporating a
device on his automatic looms that would stop the loom from
operating whenever a thread broke. Dr. Shigeo Shingo then developed
his idea further.
• This enabled great improvements in quality and freed people up to do
more value creating work than simply monitoring machines for quality
(separating people’s work and machine’s work).
• Eventually, this simple concept found its way into every machine,
every production line, and every Toyota operation.
• Poka-yoke (mistake or error proofing)
– A form of device for building-in quality at each production
– This device may take many shapes and designs.
– Typical types of Pokayoke are sensors, proximity switches,
stencils, light guards and alignment pins. Simple circuitry is
usually used to operate these electrical error proof devices
as they should be of low cost and simple design.
– Goal: Finding defects before they occur = Zero Defects
– Statistical Quality Control (SQC): Finding defects after they
• Visual management including using Andon Lamp
• Red - line stoppage
• Yellow - call for help
• Green - normal
• Change for better = continuous
• Kaizen workshop or Kaizen event:
A group of Kaizen activity, commonly lasting
five days, in which a team identifies and
implements a significant improvement in a
process, e.g., creating a manufacturing cell.
• GEMBA" is a Japanese word meaning "real place", where
the real action takes place. In business, GEMBA is where
the value-adding activities to satisfy the client are carried
• Manufacturing companies have three main activities in
relation to creating money: developing (designing),
producing and selling products. In a broad sense, GEMBA
means the sites of these three major activities.
• In a narrower context, however, GEMBA means the place
where the products are made.
• The term is often used to stress the that real improvement
can only take place when there is a shop-floor focus on
direct observation of current conditions where work is
done, e.g., not only in the engineering office.
Five Golden Rules of Gemba
• Masaaki Imai promoted Kaizen to people outside Japan through his two highly
1. Kaizen: The Key To Japan's Competitive Success.
2. Gemba Kaizen: A Commonsense, Low-Cost Approach to Management
• He preaches the Five Golden Rules of Gemba, the first of which is 'When a
problem (abnormality) arises, go to gemba first'. So what's gemba? It's the
shop floor, or equivalent. Once there, you apply
Golden Rule Two: check with gembutsu (relevant objects).
Three: take temporary counter-measures on the spot.
Four: find the root cause.
Five: standardize to prevent recurrence.
Standardization is the managing part of getting good gemba. You also need
good housekeeping (Imai is very keen on cleaning machines) and muda, the
elimination of waste. But all hinges on getting away from your desk. Obey the
master Imai. GO TO GEMBA!
5Whys: Finding the root cause of a
• 5 Whys analysis as an effective problem-solving technique. It is also used in Six Sigma.
• Why is our client, Hinson Corp., unhappy? Because we did not deliver our services
when we said we would.
• Why were we unable to meet the agreed-upon timeline or schedule for delivery? The job
took much longer than we thought it would.
• Why did it take so much longer? Because we underestimated the complexity of the job.
• Why did we underestimate the complexity of the job? Because we made a quick estimate
of the time needed to complete it, and did not list the individual stages needed to
complete the project.
• Why didn't we do this? Because we were running behind on other projects. We clearly
need to review our time estimation and specification procedures.
(PDCA/Shewart /Deming Cycle)
• Plan: Go to the real place/factory flow (gemba), obverse
the real thing/product (gembutsu), get the real fact
(genjitsu). Focus on reducing response time, lead times,
exposing wastes in your process
• Do: Conduct Kaizen. Create models of excellence so
others can aspire to. Flow everything: product, information
material replenishment, services.
• Check for direction by aligning activities with long-term
• Act: Take actions to sustain and accelerate improvement
Similarity between 3 Gs and MBWA
• The 3 G's (Gemba, Gembutsu, and Genjitsu, which
translate into “actual place”, “actual thing”, and “actual
• In the early days of Hewlett-Packard (H-P), Dave Packard
and Bill Hewlett devised an active management style that
they called Management By Walking Around (MBWA).
Senior H-P managers were seldom at their desks. They
spent most of their days visiting employees, customers,
and suppliers. This direct contact with key people provided
them with a solid grounding from which viable strategies
could be crafted.
5S: Workplace organization/Housekeeping
• 5s: Important part of Kaizen/Lean Manufacturing
• The S's stand for:
– Seiri - keep only what is absolutely necessary, get rid of things that
you don't need, i.e. simplify or sort.
– Seiton - create a location for everything, i.e. organize
– Seiso - clean everything and keep it clean, i.e. cleanliness or
– Seiketsu - implement Seiri, Seiton and Seiso plant wide, i.e.
– Shitsuke - assure that everyone continues to follow the rules of 5S,
i.e. stick to it or self discipline.
• 5S in the US: Sort, Straighten, Sweep, Standardize, Self Disciple
• 5S + 1S (Safety) = 6S (Hytrol, etc)
• 5S + 2S (Safety and Security) = 7 S (Agilent Technology that was part
of Hewlett Packard)
• 5S is simple to begin and gives good benefits.
• Each individual in an organization is asked to get
rid of overburdening items.
• Red tag attack: A red tag attack is the strategy of
a group of people going through the plant and
putting red tags on everything that has not been
used within the last 30 days. The items that
people feel are necessary to "hold on to" must be
justified to their superior, or the item is taken out
of the plant!
5S in a Factory
Factory tour: Toyota vs.
When manpower, equipment, and materials are used in the most efficient
combination, this is called Standard Work.
There are three elements to Standard Work:
1) Takt Time
2) Work Sequence
3) Standard Work-in-Process
Once a Standard Work is set, performance is measured and continuously
Standard Work Sheet
Scope of From Raw mat er i al Date Reviewed:
Operations To Heat Tr eat ment Janary 7, 2000
Quality Safety Standard Work Standard WIP TAKT Cycle Crew
Check Precaution in Process Quantity Time Time Size
223.4 min12.1 min10
The Importance of Standardized Work:
Without it, all improvement efforts using Kaizen to eliminate
waste (muda) are not sustainable. You will go back to the
original position before Kaizen.
Improving Lead Time:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Percent of Lead Time
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Approach # 1: Reducing Value Added (VA) Time by 50%
Approach # 2: Reducing Non Value Added (VA) Time by 50%
NVA (Non Value Added)
Value Stream MappingSM
• A visual tool for identifying all activities of the planning,
and manufacturing process to identify waste.
• Provides a tool to visualize what is otherwise usually
• The leaders of each product family need to have a
primary role in developing the maps for their own area.
• Develop a current-state map before improvements are
made so that the efforts and benefits can be quantified.
• On the shop floor, not from your office. You need the real
information, not opinion or old data.
• Next page
Value Stream Map Symbols
C/T = 30 sec
C/O = 10 min
2% scrap rate
Vendor Data box
= 1 day
the location of a
C/T = Cycle Time
C/O = Change over or setup time
Attributes of Lean Producers - they
• use JIT to eliminate inventory
• build systems to help employees product a
perfect part every time
• reduce space requirements
• develop close relationships with suppliers
• educate suppliers
• eliminate all but value-added activities
• develop the workforce
• make jobs more challenging
• reduce the number of job classes and build
• apply Total Productive Maintenance (TPM)
The Five Steps of Lean
• Step 1: Specify Value
Define value from the perspective of the final customer. Express value in terms of a
specific product, which meets the customer's needs at a specific price and at a specific
• Step 2: Value Stream Mapping.
Identify the value stream, the set of all specific actions required to bring a specific
product through the three critical management tasks of any business: the problem-
solving task, the information management task, and the physical transformation task.
Create a map of the Current State and the Future State of the value stream. Identify and
categorize waste in the Current State, and eliminate it!
• Step 3: Create Continuous Flow
Make the remaining steps in the value stream flow. Eliminate functional barriers and
develop a product-focused organization that dramatically improves lead-time.
• Step 4: Create Pull Production
Let the customer pull products as needed.
• Step 5: Perfection
There is no end to the process of reducing effort, time, space, cost, and mistakes. Return
to the first step and begin the next lean transformation, offering a product which is ever
more nearly what the customer wants.
MRP (Material Requirements Planning),
JIT, and TOC (Theory of Constraints)
Loading of operations
Importance of data
Speed of scheduled
Checked by capacity
One week or more
Have doable plan
Controlled by kanban
Small as possible
Final assembly schedule
Variable to exploit
Critical for bottleneck
and feeder operations
Need and plan
MRP JIT TOC