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Heizer om10 ch16-jit and lean operations
 

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    Heizer om10 ch16-jit and lean operations Heizer om10 ch16-jit and lean operations Document Transcript

    • 10/16/2010 JIT and Lean Outline 16 Operations Global Company Profile: Toyota Motor Corporation Just-in-Time, the Toyota Production System, and Lean y , PowerPoint presentation to accompany Heizer and Render Operations Operations Management, 10e Principles of Operations Management, 8e Eliminate Waste PowerPoint slides by Jeff Heyl Remove Variability Improve Throughput© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 1 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 2 Outline – Continued Outline – Continued Just-in-Time JIT Inventory JIT Partnerships Reduce Variability Concerns of Suppliers Reduce Inventory JIT Layout Reduce Lot Sizes Distance Reduction Reduce Setup Costs Increased Flexibility JIT Scheduling Impact on Employees Level Schedules Reduced Space and Inventory Kanban© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 3 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 4 Outline – Continued Learning Objectives JIT Quality When you complete this chapter you Toyota Production System should be able to: Continuous Improvement 1. Define just-in-time, TPS, and lean Respect for People operations Standard Work Practices 2. Define the seven wastes and the 5 Ss Lean Operations 3. Explain JIT partnerships Building a Lean Organization 4. Determine optimal setup time Lean Operations in Services© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 5 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 6 1
    • 10/16/2010 Learning Objectives Toyota Motor Corporation When you complete this chapter you should be able to: Largest vehicle manufacturer in the world with annual sales of over 9 million vehicles 5. Define kanban Success due to two techniques JIT techniques, 6. Compute the required number of and TPS kanbans Continual problem solving is central 7. Explain the principles of the Toyota to JIT Production System Eliminating excess inventory makes problems immediately evident© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 7 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 8 Toyota Motor Corporation TPS Elements Central to TPS is employee learning and a continuing effort to produce products under ideal conditions Respect for people is fundamental Small building but high levels of production Subassemblies are transferred to the assembly line on a JIT basis High quality and low assembly time per vehicle© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 9 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 10 JIT/Lean Operations Just-In- Just-In-Time, TPS, and Lean Operations Good production systems require JIT is a philosophy of continuous and that managers address three issues forced problem solving via a focus on that are pervasive and fundamental throughput and reduced inventory to operations management: TPS emphasizes continuous eliminate waste, remove variability, improvement, respect for people, and and improve throughput standard work practices Lean production supplies the customer with their exact wants when the customer wants it without waste© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 11 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 12 2
    • 10/16/2010 Just-In- Just-In-Time, TPS, and Eliminate Waste Lean Operations Waste is anything that does not JIT emphasizes forced problem add value from the customer point solving of view TPS emphasizes employee Storage, inspection, delay, waiting learning and empowerment in an in queues, and defective products assembly-line environment do not add value and are 100% Lean operations emphasize waste understanding the customer© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 13 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 14 Ohno’s Seven Wastes Eliminate Waste Overproduction Other resources such as energy, Queues water, and air are often wasted Transportation Efficient, sustainable production Inventory minimizes inputs, reduces waste Motion Traditional “housekeeping” has been expanded to the 5 Ss Overprocessing Defective products© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 15 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 16 The 5 Ss The 5 Ss Sort/segregate – when in doubt, Sort/segregate – when in doubt, throw it out throw it out Simplify/straighten – methods Simplify/straighten – methods analysis tools analysis additional Ss Two tools Shine/sweep – clean daily Shine/sweepbuild in good practices Safety – – clean daily Standardize – remove variations Standardize – remove variations from processes Support/maintenance – reduce from processes variability and unplanned Sustain/self- Sustain/self-discipline – review Sustain/self- Sustain/self-discipline – review downtime work and recognize progress work and recognize progress© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 17 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 18 3
    • 10/16/2010 Remove Variability Sources of Variability JIT systems require managers to 1. Incomplete or inaccurate drawings reduce variability caused by both or specifications internal and external factors 2. Poor production processes Variability is V i bilit i any d i ti f deviation from th the resulting in incorrect quantities, optimum process late, or non-conforming units Inventory hides variability 3. Unknown customer demands Less variability results in less waste© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 19 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 20 Sources of Variability Improve Throughput 1. Incomplete or inaccurate drawings The time it takes to move an or specifications order from receipt to delivery 2. Poor production processes The time between the arrival of resulting in incorrect quantities, raw materials and the shipping late, or non-conforming units of the finished order is called manufacturing cycle time 3. Unknown customer demands A pull system increases throughput© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 21 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 22 Improve Throughput Just-In- Just-In-Time (JIT) Powerful strategy for improving By pulling material in small lots, operations inventory cushions are removed, Materials arrive where they exposing problems and emphasizing are needed when they are continual improvement needed Identifying problems and Manufacturing cycle time is reduced driving out waste reduces Push systems dump orders on the costs and variability and downstream stations regardless of improves throughput the need Requires a meaningful buyer-supplier relationship© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 23 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 24 4
    • 10/16/2010 JIT and Competitive JIT and Competitive Advantage Advantage Figure 16.1 Figure 16.1© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 25 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 26 JIT Partnerships JIT Partnerships JIT partnerships exist when a supplier and purchaser work together to remove waste and drive down costs Four goals of JIT partnerships are: Removal of unnecessary activities Removal of in-plant inventory Removal of in-transit inventory Improved quality and reliability Figure 16.2© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 27 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 28 Concerns of Suppliers JIT Layout Diversification – ties to only one customer increases risk Reduce waste due to movement Scheduling – don’t believe customers can JIT Layout Tactics create a smooth schedule Build work cells for families of products Include a large number operations in a small area Lead time – short lead times mean Minimize distance engineering or specification changes can Design little space for inventory create problems Improve employee communication Quality – limited by capital budgets, Use poka-yoke devices processes, or technology Build flexible or movable equipment Lot sizes – small lot sizes may transfer Cross-train workers to add flexibility costs to suppliers Table 16.1© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 29 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 30 5
    • 10/16/2010 Distance Reduction Increased Flexibility Large lots and long production Cells designed to be rearranged lines with single-purpose as volume or designs change machinery are being replaced by smaller flexible cells Applicable in office environments as well as production settings Often U-shaped for shorter paths and improved communication Facilitates both product and process improvement Often using group technology concepts© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 31 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 32 Impact on Employees Reduced Space and Inventory Employees may be cross trained for flexibility and efficiency Improved communications With reduced space, inventory facilitate the passing on of must be in very small lots y important information about the Units are always moving because process there is no storage With little or no inventory buffer, getting it right the first time is critical© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 33 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 34 JIT Inventory Reduce Variability Inventory is at the minimum level necessary to keep operations running Inventory level JIT Inventory Tactics Use a pull system to move inventory p y y Reduce lot sizes Develop just-in-time delivery systems with suppliers Process Deliver directly to point of use Scrap downtime Perform to schedule Setup Quality Reduce setup time time problems Use group technology Late deliveries Table 16.2 Figure 16.3© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 35 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 36 6
    • 10/16/2010 Reduce Variability Reduce Variability Inventory Inventory level level Process Scrap downtime No scrap Quality problems Setup Quality Setup removed time problems time reduced Process Late downtime Late deliveries removed deliveries Figure 16.3 Figure 16.3© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 37 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 38 Reduce Inventory Reduce Lot Sizes Reducing inventory uncovers the Q1 When average order size = 200 “rocks” 200 – average inventory is 100 entory Problems are exposed Q2 When average order size = 100 Inve average i inventory is 50 t i Ultimately there will 100 – be virtually no inventory and no problems Time Shingo says “Inventory is evil” Figure 16.4© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 39 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 40 Reduce Lot Sizes Lot Size Example Ideal situation is to have lot sizes D= Annual demand = 400,000 units of one pulled from one process to d= Daily demand = 400,000/250 = 1,600 per day the next p= Daily production rate = 4,000 units Q= EOQ desired = 400 Often not feasible H= Holding cost = $20 per unit S= Setup S t cost (to be determined) t (t b d t i d) Can use EOQ analysis to calculate desired setup time 2DS 2DS Q= Q2 = H(1 - d/p) H(1 - d/p) Two key changes necessary (Q2)(H)(1 - d/p) (3,200,000)(0.6) Improve material handling S= 2D = 800,000 = $2.40 Reduce setup time Setup time = $2.40/($30/hour) = 0.08 hr = 4.8 minutes© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 41 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 42 7
    • 10/16/2010 Reduce Setup Costs Lower Setup Costs High setup costs encourage large Sum of ordering Holding cost lot sizes and holding costs Reducing setup costs reduces lot g p st Cos size and reduces average T1 inventory Setup cost curves (S1, S2) T2 Setup time can be reduced S1 through preparation prior to S2 shutdown and changeover Lot size Figure 16.5© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 43 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 44 Reduce Setup Times JIT Scheduling Initial Setup Time 90 min — Schedules must be communicated Separate setup into preparation and actual setup, doing as much as possible while the inside and outside the organization Step 1 machine/process is operating (save 30 minutes) Level schedules 60 min — Move material closer and M t i l l d improve material handling Process frequent small batches Step 2 (save 20 minutes) 45 min — Freezing the schedule helps stability Standardize and Step 3 improve tooling (save 15 minutes) Kanban 25 min — Step 4 Use one-touch system to eliminate Signals used in a pull system adjustments (save 10 minutes) 15 min — Training operators and standardizing 13 min — Step 5 work procedures (save 2 minutes) Figure 16.6 Step 6 Repeat cycle until subminute — setup is achieved© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 45 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 46 JIT Scheduling Level Schedules Better scheduling improves performance JIT Scheduling Tactics Table 16.3 Process frequent small batches Communicate schedules to suppliers rather than a few large batches Make level schedules Make and move small lots so the Freeze part of the schedule F t f th h d l level schedule is economical l l h d l i i l Perform to schedule Seek one-piece-make and one-piece move “Jelly bean” scheduling Eliminate waste Freezing the schedule closest to the Produce in small lots due dates can improve performance Use kanbans Make each operation produce a perfect part© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 47 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 48 8
    • 10/16/2010 Scheduling Small Lots Kanban Kanban is the Japanese word for card JIT Level Material-Use Approach The card is an authorization for the next A A B B B C A A B B B C container of material to be produced A sequence of kanbans q pulls material through Large-Lot Approach the process A A A A A A B B B B B B B B B C C C Many different sorts of signals are used, but the system is still called a kanban Time Figure 16.7© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 49 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 50 Kanban Kanban 1. User removes a standard sized container Material/Parts Supplier Final assembly Finished goods Customer order 2. Signal is seen by Work cell the producing department as Kanban authorization to Kanban Kanban replenish Signal marker on boxes Part numbers Figure 16.9 mark location Figure 16.8© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 51 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 52 More Kanban More Kanban When the producer and user are not in Usually each card controls a specific visual contact, a card can be used quantity or parts When the producer and user are in Multiple card systems may be used if visual contact a light or flag or empty contact, there are several components or spot on the floor may be adequate different lot sizes Since several components may In an MRP system, the schedule can be required, several different be thought of as a build authorization kanban techniques may be employed and the kanban a type of pull system that initiates actual production© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 53 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 54 9
    • 10/16/2010 More Kanban The Number of Kanban Cards or Containers Kanban cards provide a direct control Need to know the lead time needed to and limit on the amount of work-in- produce a container of parts process between cells Need to know the amount of safety If there is an immediate storage area, a area stock needed two-card system can be used with one card circulating between the user and storage area and the other between the Demand during Safety Number of kanbans lead time + stock storage area and the producer (containers) = Size of container© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 55 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 56 Number of Kanbans Example Advantages of Kanban Daily demand = 500 cakes Production lead time = 2 days Allow only limited amount of faulty or (Wait time + delayed material Material handling time + Processing time) g ) Problems are immediately evident Safety stock = 1/2 day Puts downward pressure on bad Container size = 250 cakes aspects of inventory Demand during lead time = 2 days x 500 cakes = 1,000 Standardized containers reduce weight, disposal costs, wasted space, 1,000 + 250 and labor Number of kanbans = 250 =5© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 57 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 58 JIT Quality JIT Quality Tactics Strong relationship Use statistical process control JIT cuts the cost of obtaining good Empower employees quality because JIT exposes poor quality Build fail safe methods (poka- fail-safe (poka Because lead times are shorter, yoke, checklists, etc.) quality problems are exposed sooner Expose poor quality with small Better quality means fewer buffers lot JIT and allows simpler JIT systems to be used Provide immediate feedback Table 16.4© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 59 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 60 10
    • 10/16/2010 Toyota Production System Toyota Production System Continuous improvement Standard work practice Build an organizational culture and value system that stresses improvement of all Work shall be completely specified as to processes, kaizen content, sequence, timing, and outcome Part of everyone’s j y job Internal and external customer-supplier connection are direct i di Respect for people Product and service flows must be simple People are treated as and direct knowledge workers Any improvement must be made in Engage mental and accordance with the scientific method at the physical capabilities lowest possible level of the organization Empower employees© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 61 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 62 Lean Operations Building a Lean Organization Transitioning to a lean system can Different from JIT in that it is be difficult externally focused on the customer Lean systems tend to have the Starts with understanding what the following attributes customer wants Use JIT techniques Optimize the entire process from Build systems that help employees the customer’s perspective produce perfect parts Reduce space requirements© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 63 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 64 Building a Lean Organization Lean Operations in Services Develop partnerships with suppliers The JIT techniques used in Educate suppliers manufacturing are used in services Eliminate all but value-added Suppliers activities acti ities Layouts Develop employees Inventory Make jobs challenging Scheduling Build worker flexibility© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 65 © 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 66 11
    • 10/16/2010 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Printed in the United States of America.© 2011 Pearson Education, Inc. publishing as Prentice Hall 16 - 67 12