Lean Operations and TPS The History of Toyota Seven Sources of - - PDF document

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2015/5/31 Lean Operations and TPS The History of Toyota Seven Sources of Waste JIT and Quality Improvement Flexibility, Standardization, and HR Practices Henry Ford and Model T Interchangeable parts and moving assembly line

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Lean Operations and TPS

 The History of Toyota  Seven Sources of Waste  JIT and Quality Improvement  Flexibility, Standardization, and HR Practices

Henry Ford and Model T

Interchangeable parts and moving assembly line streamlined the production process and reached an unmatched economy of scale.

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The History of Toyota

 Toyota switched from automated looms to

military trucks just prior to WWII.

 Shortage of supplies led to simplistic design

f its vehicles.

 Mass production, with its emphasis on scale economies and

large investment in machinery did not fit Toyota’s environment of a small domestic market and little cash.

 Secondhand equipment and high unit costs forced Toyota to

reduce waste and improve quality whenever possible.

 TPS is the outcome of a long evolution.

Comparing Toyota, GM, and Ford

20 40 60 80 100 120 140 160

Aug-89 Aug-90 Aug-91 Aug-92 Aug-93 Aug-94 Aug-95 Aug-96 Aug-97 Aug-98 Aug-99 Aug-00 Aug-01 Aug-02 Aug-03 Aug-04 Aug-05 Aug-06 Aug-07

Stock Price in US$ Toyota GM Ford

1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 1965 1988 2000 2006

Toyota GM Ford

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Global Benchmarking by IMVP

 The first true proof of superiority of TPS.  GM failed to reduce non‐value‐added

activities that did not contribute the production of the vehicle.

TPS Framework

Zero non‐value added activities (muda) Zero defects, zero breakdowns, zero inventory, zero set‐up Production flow synchronized with demand (JIT)

One‐unit‐at‐a‐time flow Mixed model production (heijunka) Piece‐by‐piece transfer (ikko‐nagashi) Match production demand based on Takt time Pull instead of push Supermarket / Kanban Make‐to‐order

Quality methods to reduce defects

Fool‐proofing (poka‐yoke) and visual feed‐back Detect‐stop‐alert (Jidoka) Defects at machines (original Jidoka) Defects in assembly (Andon cord) Build‐in‐quality (tsukurikomi)

Flexibility Standardization of work Worker involvement

Quality circles (Kaizen) Fishbone diagrams (Ishikawa) Skill development / X‐training Reduction of Variability Quartile Analysis Standard operating procedures Adjustment of capacity to meet takt‐time Multi‐task assignment (takotei‐mochi)

Reduce inventory to expose defects

10.3 10.4 10.5 10.6 10.7 10.9 10.8

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10.3 Seven Sources of Waste

 Overproduction: too much or too early  Waiting: idle time and low utilization  Transport: internal transport does not create value  Over‐processing: use expensive materials or spend too

much processing times

 Inventory: hide problems and leads to long flow times  Rework: “Do it right the first time”  Motion: use the right tool and avoid unnecessary body

movements

Example: SMED快速換模

Large set up cost  Large production lot size  Large inventory

事先調整定位、簡易拆卸、預熱模具

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The Concept of Waste for Hospitals

 Most nurses spend too much time on non‐nursing activities.  This waste leads to heavy workload for nurses, poor care for

patients, and high costs for health care institutions.

 Only 60% of the capacity of an operating room is used

productively because

 gaps in the schedule  procedure is cancelled  room cleaning time  procedure delays because of late arrivals

10.4 JIT: Achieve One-Unit-at-a-Time Flow

 An elevator is a batch process which leads to long wait times.  Escalators keep people moving constantly without waiting.

mixed model production

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JIT: Produce at the Rate of Customer Demand

 Most large scale operations have operated based on MRP and

forecasts.

 Extensive periods of large inventories or customer backorders

exist.

 TPS aims at reducing FGI by operating its process in

synchronization with customer orders.

 Customer demand is translated

into takt time to control the production rate.

JIT: Implement Pull Systems

 In a push system, flow units are released to the

process regardless of the current amount of inventory in process.

 In a pull system, the resource closest to the market is

paced by demand. It also relays the demand information to the next station upstream.

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Example: Kanban Systems

看板是一種控制物料的方法，看板在物料生產過程中提供相關資訊，包括時間、規格、數量、運送地點等

Kanban Flow Control

A B 前製程後製程 A B 上游 1 市場 2 4 P看板 5 6 2 P看板 6 W看板 3 W看板

運送看板(Withdrawl)：各站完成加工的產品必須得到下游的運送看板才能前進生產看板(Production)：各站等待加工的產品必須得到該站的生產看板才能進行加工

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JIT Delivery and Focused Factory Networks

減少零組件庫存直接配送至生產線使用地點少量多次補貨選擇鄰近供應商發展成中衛體系簡化訂貨與驗收協助供應商改善品質 quality at the source

Make-to-Order vs. Kanban Systems

 Make‐to‐order: every flow unit in the process is assigned to

ne specific customer order.

 Low volume and large variety  Customers are willing to wait  Inventory is expensive

 Kanban: a flow unit in the process is not designated to fill any

specific customer order

 High volume and low variety  Short order lead times  Costs and efforts to store the components are low

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10.5 Quality Improvement

 Zero defects lead to operations without

buffers and no waste of rework.

 Pokayoke (fool‐proofing) reduces the

possibility of making mistakes.

 Jidoka means stopping the process

immediately whenever a defect is detected.

 Quality inspection is built in at every

step, as opposed to relying on the final inspection.

10.6 Exposing Problems thru Inventory Reduction

 Inventory covers up problems.  Gradually reducing inventory exposes

problems and forces improvement.

18 Inventory in process Buffer argument: “Increase inventory” Toyota argument: “Decrease inventory”

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10.7 Flexibility of the Workforce

 Need flexible processes to meet demand fluctuations.  Flexible processes requires multiple‐skilled workers.  The management should provide standard operating

procedures, cross‐training, job rotation, and skill‐based payment.

19 If demand is high, takt time=1 minute

Step 1

If demand is low, takt time = 2 minutes

Step 2 Step 3 Step 4 Step 5 Step 6 Step 1 Step 2 Step 3 Step 4 Step 5 Step 6

10.9 Human Resource Practices

 The eighth source of waste: human intellect  “In our company, we all have two jobs: (1) to do our job and

(2) to improve it.”

 Quality circles bring workers together to jointly solve

production problems.

 Lifelong employment for the core workers.  Strong emphasis on skill development  Financial rewards

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Fishbone Diagram: 5 Whys for Continuous Improvement Summary

 There is more to a successful operational turnaround than

the application of a set of tools.

 An emphasis on flow, matching supply with demand, and a

close eye on the variability of the process.

 A management infrastructure based

n right performance measures.

 Mindsets of employees are involved