LEAN SYSTEMS

ARRON O. ENRIQUEZ
 CONCEPT
“Lean” is not an acronym
• It means to do more with less waste
Most processes in are 95% waste
• Actual hands-on time is only 5%
The largest production gains will be made in reducing
the waste in a process
 THEREFORE:

Lean is
“A systematic approach to identifying and eliminating
waste(non-value-added activities) through continuous
improvement by flowing the product at the pull of the
customer in pursuit of perfection.”

By The MEP Lean Network

 A LITTLE HISTORY!

Ford: Design for manufacturing

Start with an article that suits and then study to find some
way of eliminating the entirely useless parts. This applies to
everything— a shoe, a dress, a house, a piece of machinery, a
railroad, a steamship, an airplane. As we cut out useless parts and
simplify necessary ones, we also cut down the cost of making.
...But also it is to be remembered that all the parts are designed
so that they can be most easily made."
 5 KEY PRINCIPLES
Value
Value Stream
Flow
Pull
Perfection
 WHAT IS VALUE?

Specific product that meets a customer’s needs at a specific

price and specific time
What is important to the customer
What the customer is willing to pay for
Put yourself in the customer’s shoes
Use the customer’s words to describe the product
 WHAT IS THE VALUE STREAM?

Set of specific actions required to bring a specific product

through 3 critical management tasks of all businesses
• Problem Solving task (design, engineering)
• Information Management task (order taking, scheduling,
planning)
• Physical Transformation task (from raw material to finished
product)
 WHAT IS FLOW?

• Parts “flow” through a Value Stream

• Upstream is the beginning or “head” of the flow
• Downstream is the “mouth” of the flow, where the part
is pulled by the customer
• Materials and parts are the “parts” in manufacturing
• Customer’s needs are the “parts” in service industry
oSame for administration
 WHAT IS PULL?

• “It has become a matter of course for customers, or users, each

with a different value system, to stand in the frontline of the
marketplace and, so to speak, pull the goods they need, in the
amount and at the time they need them.”
-Taiichi Ohno, “Toyota Production System”
• “…Nothing is produced by the upstream provider until the
downstream customer signals a need”
-Womack and Jones, “Lean Thinking”
 WHAT IS PERFECTION?

•The complete elimination of all waste,

so that all activities along a value
stream add value to the product
 A LITTLE HISTORY!

Ohno – put ideas into practice systematically

• “When bombarded with questions from our group on
what inspired his thinking, Ohno just laughed and said
he learned it all from Henry Ford's book."
 TPS: TOYOTA PRODUCTION SYSTEM

•A system that continually searches for and

eliminates waste throughout the value chain.
•Views every enterprise activity as an operation
and applies its waste reduction concepts to
each activity - from Customers to the Board
of Directors to Support Staff to Production
Plants to Suppliers.
 PULL/PUSH SYSTEMS

•Pull system: System for moving work where a

workstation pulls output from the preceding
station as needed. (e.g. Kanban)
•Push system: System for moving work where
output is pushed to the next station as it is
completed
 MUDA (WASTE)

Taiichi Ohno (1912-1990), the Toyota executive who was the most ferocious foe of waste
human history has produced, identified the first seven types of muda in manufacturing
system:

• Storage
• Transportation
• Waiting
• Motion
• Process
• Defects
• Over-production
•
• Muda is everywhere.
 ELIMINATION OF WASTE

1. 5S
2. Group technology
3. Quality at the source
4. JIT production
5. Kanban production control system
6. Minimized setup times
7. Uniform plant loading
8. Focused factory networks
 MINIMIZING WASTE – 5S

• “Good factories develop beginning with the 5S’s. Bad factories fall apart beginning with
the 5 S’s.”
• - Hirouki Hirano

Japanese Translation English

Seiri Proper arrangement Sort
Seiton Orderliness Simplify
Seiso Cleanliness Sweep
Seiketsu Cleanup Standardize
Shitsuke Discipline Sustain
 A TOOL TO ORGANIZE THE WORKPLACE

• Sort—Keep what you need, get rid of the rest

• Straighten—Organize what’s left
• Scrub—A clean workplace is more efficient
• Standardize—Find a best way and have everyone do it
that way
• Sustain—Don’t let up
Minimizing Waste: Group Technology
Using Departmental Specialization (Job Shop) for plant layout
can cause a lot of unnecessary material movement

Note how the flow lines are going back and forth

Saw Saw Saw Grinder Grinder

Heat Treat

Lathe Lathe Lathe Press Press Press

MINIMIZING WASTE: GROUP
TECHNOLOGY
Revising by using Group Technology Cells can reduce
movement and improve product flow

Grinder
1 2
Saw Lathe Lathe Press

Heat Treat

Grinder
Saw Lathe A B Lathe Press
Minimizing Waste: JIT
• Only produce what’s needed
• The opposite of “Just In Case” philosophy
• Ideal lot size is one
• Minimize transit time
• Frequent small deliveries

Pro’s Con’s ???

 Minimal inventory  Requires discipline
 Less space  Requires good problem solving
 More visual  Suppliers or warehouses must be
 Easier to spot quality issues close
 Requires high quality
Minimizing Waste: JIT
INVENTORY
HIDES
PROBLEMS
Machine
downtime

Scrap Vendor
Work in delinquencies Change
orders
process
queues Engineering design Design
(banks) redundancies backlogs

Paperwork Inspection Decision

backlog backlogs backlogs

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MINIMIZING WASTE – QUALITY
AT THE SOURCE
• “Do it right the first time”
• Call for help
• Immediately stop the process and correct it vs. passing it on to inspection or repair
Andon
 JIDOKA – each worker is expected to perform
ongoing quality assurance, objective is to avoid
passing defective products to the following work
station
 Minimizing Waste – Kanban
Signaling device to control flow of material
 Cards
 Empty containers
 Lights
 Colored golf balls
 Etc
• Kanban: Card or other device that communicates
demand for work or materials from the preceding
station
• Kanban is the Japanese word meaning “signal” or
“visible record”
• Paperless production control system
• Authority to pull, or produce comes
• from a downstream process.
 MINIMIZING WASTE – SETUP TIMES
 Long setup times drive:
Long production runs
Large lots
Long lead times
 JIT requires small lots and minimum kanbans
 Setup reduction
Focused efforts
Problem solving
Flexible equipment
 MINIMIZING WASTE – PLANT
LOADING
Heijunka
Suppose we operate a production plant that produces a single
product. The schedule of production for this product could be
accomplished using either of the two plant loading schedules below.

Not uniform Jan. Units Feb. Units Mar. Units Total

1,200 3,500 4,300 9,000

or
Uniform Jan. Units Feb. Units Mar. Units Total
3,000 3,000 3,000 9,000

How does the uniform loading help save labor costs?

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MINIMIZING
WASTE –
FOCUSED These are small specialized
plants that limit the range of
FACTORY products produced
NETWORKS (sometimes only one type of
product for an entire facility)
• The major advantage is that
material flow is significantly
improved, which reduces the
distance travelled by materials,
Coordination inventory and cumulative lead
System Integration times.
 TPS – RESPECT FOR PEOPLE
• Level payrolls
• Cooperative employee unions
• Subcontractor networks
• Bottom-up management style
• Quality circles (Small Group Problem
KeiretsuSolving)
 LEAN IMPLEMENTATION
Total Quality
Management

Product Flow
Design Process

Empowered Workforce
Problem Solving
Continual Inventory Performance Measurement Stable
Reduction Schedule

Involved Kanban
Suppliers Pull
 PRODUCT DESIGN
• Standard parts – fewer parts to deal with lower
training costs
use standard processing
• Modular design – clusters of parts treated as a single
unit.  easy to satisfy different needs
• Highly capable production systems – quality is designed
into the product and the production process
• Concurrent
• engineering
 PROCESS DESIGN

• Small lot sizes

• Setup time reduction
• Manufacturing cells
• Limited work in process
• Quality improvement
• Production flexibility
• Little inventory storage
 PRODUCTION FLEXIBILITY

• Reduce downtime by reducing changeover

time - small lots require frequent setups.
• SMED (single minute exchange of die)
• External
• Internal activities.
• Use preventive maintenance to reduce
breakdowns
 QUALITY IMPROVEMENT

• Autonomation – automatic detection of defects

during production. It refers to jidoka
• It consist two activities:
One for detecting defects when they occur
Another for stopping production to correct the
cause of defects.
 WORK FLEXIBILITY

• Overall goal of lean is to achieve the ability

to process mix of products in a smooth
flow.
• One potential obstacle is bottlenecks, which
occur when portions of the system become
overloaded.
 BALANCED SYSTEM
• Distributing the workload evenly among workstations
• Takt time – is the cycle time needed in the production system to match
the pace of production to the demand rate
• Example:
• Total time per shift is 480 minutes per day
• There are two shifts per day
• There are two 20-minutes break and a 30 minutes lunch break per shift.
• Daily demand is 80 pieces
• Net time available per day= 2*(480-20*2-30)=820minutes
• Takt time=820minutes/80 pieces=10,25 minutes
• If the actual cycle time is higher, our customers won’t get their needs, if
the actual cycle time is lower, there will be overproduction, and we have
to inventory surplus products.
 INVENTORY STORAGE

• Inventory storage in the lean philosophy is a waste, a buffer which can

cover up problems, partly because inventory makes them seem less
serious.
• When a machine breaks down it won’t disrupt the system if there is a
sufficient inventory of the machine’s output.
• Lean approach is to eliminate inventories in order to uncover the
problems and solved. Then the system removes more inventory, finds
and solves additional problems.
• One way of minimizing inventory is to have delivers from suppliers go
directly to the product floor . At the end of the process completed units
shipped out as soon as possible-JIT
• But less inventory has also some risk: if a problem arises there is no
safety net.
 FAIL- SAFE METHODS

• The same as poka-yoke, when safeguards are built

into a process to reduce or eliminate the potential
errors.
• The contact method identifies product defects by testing
the product's shape, size, color, or other physical
attributes.
• The fixed-value (or constant number) method alerts the
operator if a certain number of movements are not made.
• The motion-step (or sequence) method determines
whether the prescribed steps of the process have been
followed.
• Alarm if the weight of a packaged item is too low,
• ATM signal if the card is left in the machine
PERSONNEL/ORGANIZATIONAL ELEMENTS

• Workers as assets
• Cross-trained
workers
• Continuous
improvement
• Cost accounting
• Leadership/project
management