Tube cutting. Tube bending. Mitering. Welding. Washing

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MSE595LMLean Manufacturing
Chapter 3Flow
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Flow - Definition

• The production system Henry Ford introduced at
  his Highland Park, Michigan plant in 1913.
• The objective of flow production was to
  drastically reduce product throughput time and
  human effort through a series of innovations.
• Consistently interchangeable parts so that cycle
  times could be stable for every job along an
  extended line
• The line itself
• The reconfiguration of part fabrication tasks so
  that machines were lined up in process sequence
  with parts flowing quickly and smoothly from
  machine to machine
• Production control system insuring that the
  production rate in parts fabrication matched the
  consumption rate of parts in final assembly.

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The World of Batch-and-Queue

• What happens when you go to your doctor?
• Make appointment days ahead
• Arrive on time and wait in waiting room
• Doctor behind schedule
• Referral to a specialist
• Laboratory tests
• Wait for results
• Treatment or medication given
• Trip to pharmacy or to specialist
• Hospitalization whole new disconnected
  processes and waiting
• What happens when you take a flight?
• What happens when you build a custom home?
• As the customer, you pay for all the waiting and
  rework
• The creation, ordering, and provision of any good
  or any service can be made to flow.

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How to Obtain Flow?

• Think about ways to
• Line up all of the essential steps needed to get
  a job done
• Obtain a steady, continuous flow
• No wasted motions
• No interruptions
• No batches
• No queues
• Continuous Flow changes everything
• How we work together
• The kinds of tools we devise to help with our
  work
• The organizations we create to facilitate the
  flow
• The kinds of careers we pursue
• The nature of business firms and their linkage to
  each other
• The society

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The Techniques of Flow

• Step 1 Focus on the actual object
• The specific design
• The Specific order
• The product itself
• Step 2 Ignore traditional boundaries of
• Jobs
• Careers
• Functions and
• Firms
• Form lean enterprise removing all obstacles to
  the continuous flow
• Step 3 Rethink specific work practices and tools
  
• Eliminate backflows, scrap, and stoppages so that
  the design, order, and production of the specific
  product can proceed continuously
• All three steps must be taken together

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Example From Batch to Flow in BicyclesThe
Design Step

• Marketing department determined a need
• Product engineers design a product to serve the
  need
• Prototype department built a prototype to test
  the design
• Tooling department designed tools to make a
  high-volume version of the approved prototype
• Production engineering figured out how to use the
  tools to fabricate the frame and to assemble the
  component parts into a completed bike
• Purchasing department arranged to buy the
  necessary component parts for delivery to the
  assembly line once the design was finalized
• The design moved from department to department
  waiting in the queue
• Frequent reworked or secretly reengineered to
  deal with incompatibilities between the process
  steps

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Example From Batch to Flow in BicyclesDesign
Using The Lean Approach

• Create truly dedicated product teams with all the
  skills required to conduct the following in one
  room in short period of time
• Value specification
• General design
• Detailed engineering
• Purchasing
• Tooling
• Production planning
• Quality Function Deployment (QFD)
  decision-making methodology utilizing
  standardized work to ensure process
  repeatability
• Throughput time accurately measured
• Design methodology continuously improved

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Example From Batch to Flow in BicyclesOrder-Taki
ng

• Sales department obtain orders from retailers
• Scheduling department in Operations or
  Manufacturing work the production schedules for
  the various products
• Customers call the Sales department to status
  late orders
• Sales calls Scheduling
• When customers threaten to cancel orders, Sales
  and Scheduling expedite the orders
• Sales and Scheduling had been combined in the
  early 1990s
• Computerized systems make instantaneous order
  changes and sometimes electronically transmitted
  to the customers

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Example From Batch to Flow in BicyclesOrder-Taki
ng Using the Lean Approach

• Sales and Production Scheduling are core members
  of the product team
• In a position to plan the sales campaign as the
  product design is being developed
• Sale with a clear eye to the capabilities of the
  production system so that both orders and the
  product can flow smoothly from sale to delivery
• No stoppages in the production system
• Products are built to order
• Only few hours elapse between the first operation
  on raw materials and shipment of the finished
  item
• Orders can be sought and accepted with clear and
  precise knowledge of the systems capabilities
• There is no expediting!

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Takt Time

• Precisely synchronizes the rate of production to
  the rate of sales to customers
• Takt Time Calculation Example
• Customers are placing orders at the rate of
  48/day
• Bike factory works a single eight-hour shift
• Takt time adjusted as orders increase or decrease
  over time
• The production slots created by the Takt Time are
  clearly posted on whiteboard or electronic
  displays (andon boards)
• Lean technique transparency or visual control
  everyone can see where production stands at every
  moment

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Takt Time
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Key Points About Takt Time
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Example From Batch to Flow in BicyclesProduction

• Historic practice was to differentiate production
  activities by type and to create departments for
  each type of activity.
• Frame and handle bars
• Tube cutting
• Tube bending
• Mitering
• Welding
• Washing
• Painting
• Final Assembly of complete bike
• Over time, higher speed machines with higher
  levels of automation were developed for cutting,
  bending, welding, and painting
• Assembly lines to assemble a mix of high-volume
  models
• Large batches made before changing over to run
  the next part
• Large inventory

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Bicycle Plant Layout and Flow
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• Continuous Flow Factory

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Continuous Flow Production

• Remember!
• Make It Flow
• Feed the Flow
• Link the Flow

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Continuous Flow Production
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Steady Velocity
2 WEEKS!
When do we get our Parts?
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Connected Lines
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Layout change
Before
GearHobbing
ManualDeburring
ToothChamfer
HoleBoring
Gear Shaving
In
Out
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Summary of Benefits

• Work flow levels are reduced and progress is
  visible at a glance
• The ability to cross train is enhanced
• Work team members take ownership of full process
  and can help each other
• Quick problem identification and feedback
• Reduced Cycle Time
• Improved quality through cycle of learning
• Information flow and decision making enhanced
• Value-added ratio improved
• Reduces transportation waste
• Reduces material handling
• Helps to identify root causes of quality problems
• Allows for equipment dedication
• Drives set-up times down

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Rules for Kanban Systems

• 1) Pull from the downstream process (or
  customer) drives the system.
• 2) All product or inventory is under kanban
  control.
• 3) Only an empty kanban authorizes production.
• 4) Never pass a known defect downstream.
• 5) Use gradual kanban reductions to drive
  improvement.

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Purpose of a Kanban System
1) Authorize production 2) Authorize
movement. 3) Limits amount of inventory in the
system. 4) A tool for driving continuous
improvement.
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Kanban
Is a signal that

• The signal can be a
• Card
• Square
• Box
• Pigeon hole
• Light
• Etc.
• Electronic Signal
• Racks
• Shopping Carts
• MRK ( Manufacturing Ready Kit)

• Authorizes production

• Authorizes movement

• Limits inventory

• Drives continuous improvement

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How Many Kanbans?
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Example
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Pull Production System

• Definition
• A customer driven system that produces and moves
  a product/service only when the customer needs it.

Customer Pulls
Kanban 1
Kanban 2
Kanban 3
Work Center A
Work Center B
Work Flow
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Kanban Example
Condo-ban!!
Who is full?
Who needs work?
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Kanban
Unit in build
Units ready for calibration
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SMT Kanban
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Kanban Light (More Work)
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4-754 MRKManufacturing Ready Kit The empty kit
signals for replenishment
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4-754 MRK
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Homework Assignment

• Questions
• Explain what is meant by Continuous Flow
  Production
• What is Takt Time? What is Takt Rate? Why is it
  important to know them?
• Read Lean Thinking Chapter 4 - Pull
• Pages 67 - 89

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Questions? Comments?