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Lean Thinking MGMT 511. Lean Thinking. A philosophy Principles Practices For the design, operation, management, control and continuous improvement of a production system. Objectives of Lean. Produce the … Highest quality At the lowest possible cost Within a short cycle time. Lean.
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Lean Thinking • A philosophy • Principles • Practices • For the design, operation, management, control and continuous improvement of a production system.
Objectives of Lean • Produce the … • Highest quality • At the lowest possible cost • Within a short cycle time
Lean • Pioneered and developed by Toyota • TPS – Toyota Production System • Womack and Jones invented the name Lean • 3 important principles • Minimize waste • Continuous improvement • Respect for workers
Lean • Lean is a philosophy that recognizes waste as the primary driver of cycle time, cost, and quality • and employs techniques to continually drive out waste in processes.
Waste is ‘anything other than the minimum amount of equipment, materials, parts, space, and worker’s time, which are absolutely essential to add value to the product.’ — Shoichiro Toyoda President, Toyota
Lean Becoming lean is the process of eliminating waste with the goal of creating value. It is not just about waste, it is also about value.
Producer “push” Movement of materials High volume Inspection Expert-driven Decomposition Periodic adjustment Large lot sizes Statistical Quality Control Customer “pull” Flow of value Flexible response Prevention Knowledge-driven Integration Continuous improvement Lot size of 1 Quality at the source ContrastTraditional Lean
Inspection is expensive Infer from samples to save costs Inspect quality into the product Why? Can’t anyone do it? Inference implies risk of errors. Why are defects acceptable? Build it into the product Statistical Quality ControlTraditional Lean
Historical Context • Selected elements of the TPS implemented over 3 decades • Pull • Kanban (card) system • Production leveling • Reduced set-up time • Kaizen (continuous improvement) • Poka-yoke (error proofing) • Adnon (visual display)
Example – Kanban 1950’s – First Kanban experiments 1960’s – Kanban introduced company-wide 1970’s – Kanban introduced to suppliers
5 Principles of Lean • Customer value: precisely specify value by product and service • Value stream: identify the stream for each product or service • Flow: no interruption • Pull: customer pulls value • Pursue Perfection: don’t compete Source: Womak and Jones
Value Definition • Define customer needs • Opposite of waste • Use as metric
Value Stream Analysis • Value Stream Map • Critically assess Value-Added at each step • Eliminate or minimize Non-Value-Added activities.
Value Added Activities • Product or service is transformed into a state required for the customer. • Activities for which the customer is willing to pay. • VA
Non-Value Added Activities • Activities which consume resources but create no value in the eyes of the customer. • Customer is not willing to pay for these. • NVA
Non-Value Added but Needed (or Necessary) Activities • Activities causing no value added, but… • Which cannot be eliminated based on current state of technology or thinking. • NVA-N
Flow • Continuous flow through the value stream. • Make each product, each day, in direct proportion to demand. • Move from traditional batching to small lot (or 1 unit) flow. • Stability through reliability, quality and standardized work
Pull • Pull the product through the value stream • Authorize production – customer demand drives the process • Cap WIP • Kanban – signaling for required parts as they are needed
Perfection • Create a clear vision of perfection • Production ideals • Customer value • Make waste visible and evident • Problem solve
What is Waste • Any activity that is not adding value in the creation process of the product or service. • Non-value added • Non-value added but necessary
7 Types of Waste • Defects in outputs • Overproduction: not needed • Inventories: for consumption or processing • Unnecessary Processing • Unnecessary Movement of people • Unnecessary Conveyance of output. • Waiting – for information, people, equipment
The Hidden Factory • Stockrooms • Material movers and moving equipment • Expeditors • Scrap • Rework • Obsolescence
Commonly Used Tools • 5 S • The visual factory • Kaizen • Poka Yoke • Total Productive Maintenance (TPM) • Single minute exchange of die (SMED) • Takt time
5 S • Simplify or Sort (seiri) – needed vs. unneeded items • Straighten or Set (seiton) – keep in correct place • Scrub or Shine (seiso) – keep clean and tidy • Stabilize or Standardize (seiketsu) – use standard methods • Sustain or Self-Discipline (shitsuke) – do not fall back to old way of doing things
The Visual Factory • Make problems visible • Charts to show performance • Visual production and schedule boards • Kanban (visible card signal)
Kaizen • Continuous Improvement • Improvements may be small • However, many small improvements over time add up to major improvement
Common Poka-Yoke Examples (from John Grout’s Poka-Yoke Web Page)“Mistake Proofing”
Total Productive Maintenance (TPM) • Impact on waste - breakdowns, setups, reduced speed • TPM – Identify ways to maximize equipment effectiveness
Single Minute Exchange of Dies(SMED) • Original term now extended to all setup time reduction efforts • Fast setup or change-over • Allows flexible use of machines – smaller lot sizes, reduced inventory • Cost reduction • More effective use of machines
Takt Time • The rhythm of flow through a value stream • Available weekly, daily or shift time • Divided by… • Anticipated average weekly, daily or shift demand
Factory Physics • Increase the velocity of flow of material • Increasing flow is accompanied by reduction in inventory • As velocity increases, the cost of the hidden factory decreases
Benefits of Lean • Cost savings • Revenue increases • Investment savings • Workforce improvements • Uncovering problems
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 © 1998 by Prentice Hall, Inc. A Simon & Schuster Company Upper Saddle River, N.J. 07458 Transparency Masters to accompany Operations Management, 5E (Heizer & Render) 12S-13
5 Tools for Improving Flow • Process observation sheet • Process flow diagram (we have done) • Physical process map • Time Value Map • Takt Time (we have discussed)
What is Just-in-Time? • Management philosophy of continuous and forced problem solving • Supplies and components are ‘pulled’ through system to arrive where they are needed when they are needed. © 1998 by Prentice Hall, Inc. A Simon & Schuster Company Upper Saddle River, N.J. 07458 Transparency Masters to accompany Operations Management, 5E (Heizer & Render) 12S-8
What Does Just-in-Time Do? • Attacks waste • Anything not adding value to the product • Customer’s perspective • Exposes problems and bottlenecks • Caused by variability • Deviation from optimum • Achieves streamlined production • By reducing inventory © 1998 by Prentice Hall, Inc. A Simon & Schuster Company Upper Saddle River, N.J. 07458 Transparency Masters to accompany Operations Management, 5E (Heizer & Render) 12S-9
Inventory • Traditional: inventory exists in case problems arise • JIT objective: Eliminate inventory • JIT requires • Small lot sizes • Low setup time • Containers for fixed number of parts • JIT inventory: Minimum inventory to keep system running © 1998 by Prentice Hall, Inc. A Simon & Schuster Company Upper Saddle River, N.J. 07458 Transparency Masters to accompany Operations Management, 5E (Heizer & Render) 12S-32
Lean • Continues from Just-in-time discussed in the text. • Most recent approach to reducing waste and speeding the flow of product or service to the customer.
What Lean is Not • A quick fix. • Easy to do.