Operations Management Toyota Production System (TPS),

Just-in-Time (JIT), and Lean Manufacturing

Muhammad Adeel JavaidTPS Practitioner and Consultant

History• Sakichi Toyoda, the founder of the Toyota group of

companies, started Toyota as a textile machine company.

• Kiichiro Toyoda, son of Sakichi and founder of the Toyota automobile business, developed the concept of Just-in-Time in the 1930s. He decreed that Toyota operations would contain no excess inventory and that Toyota would strive to work in partnership with suppliers to level production.

• Taiichi Ohno, Toyota's chief of production in the post-WWII period. He was THE main developer of Toyota Production System (TPS).

• Dr. Shigeo Shingo: A consultant to Toyota.

PS: Shingo Prize is the highest manufacturing excellence award in the U.S. The prize is given both to companies and individuals who contribute to the development of manufacturing excellence.

History (cont.)• Toyota Production System (TPS) drew wide attention from the industrial

community because Toyota was a profitable car company in Japan during and after the oil embargo in 1970s.

• Outside Japan, dissemination began in earnest with the creation of the Toyota-General Motors joint venture-NUMMI (New United Motor Manufacturing Inc.) in California in 1984.

• Widespread recognition of TPS as the model production system grew rapidly with the publication in 1990 of The Machine That Changed the World: The Story of Lean Production, the result of five years of research led by the Massachusetts Institute of Technology.

• The MIT researchers found that TPS was so much more effective and efficient than traditional, mass production that it represented a completely new paradigm and coined the term lean production to indicate this radically different approach to production.

• The term was coined by John Krafcik, a research assistant at MIT with the International Motor Vehicle Program in the late 1980s. He then worked for General Motors and now is a Vice President of Hyundai, U.S.

Toyota Production System (TPS)• Definition: The production system developed by Toyota

Motor Corporation to provide best quality, lowest cost, and shortest lead time through the elimination of waste.

• TPS is comprised of two pillars, Just-in-Time and Jidoka (autonomation) , and is often illustrated with the "house" shown on the next slide.

• TPS is maintained and improved through iterations of standardized work and kaizen (continuous improvement), following Plan–Do-Check-Act (PDCA Cycle from Dr. Deming), or the scientific method.

House of Toyota

Toyota Production System (TPS):Related Terms

• Ohno System • MAN (Material as Needed) - Harley Davidson• MIPS (Minimum Inventory Production

Systems) - Westinghouse• Stockless production - Hewlett Packard• Zero inventory production system• Lean Manufacturing/Production - MIT

How to make money?Profit equation: Sales – Cost = Profit

Traditional pricing strategy: Cost + Profit = Selling price

Example:

When the cost goes up, the product selling price is raised to reflect the higher costs and maintain the desired level of profit.

Some even argues that the profit added should be large enough to cover potential losses if the product does not sell well.

Toyota accepts neither this formula nor these arguments!

Toyota’s philosophy• Selling price – Cost = Profit • Customers decide the selling price.• Profit is what remains after subtracting the cost from it.• The main way to increase profit is to reduce cost.• Consequently, cost reduction through waste elimination

should have the highest priority.• Toyota’s paradox: Reducing cost (waste), will reduce lead

time while increasing quality and customer satisfaction.• How? We will discuss it soon.

House of Toyota

• Attacks waste– Anything not adding value to the product

• From the customer’s perspective

• Exposes problems and bottlenecks caused by variability– Deviation from optimum

• Achieves streamlined production– By reducing inventory

What Does Just-in-Time Do?

Waste (“muda” in Japanese) 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 Founder, Toyota

© 1995 Corel Corp.

Introductory Quotation

Variability Occurs Because

• Employees, machines, and suppliers produce units that do not conform to standards, are late, or are not the proper quantity

• Engineering drawings or specifications are inaccurate

• Production personnel try to produce before drawings or specifications are complete

• Customer demands are unknown

Continuous Flow

• Producing and moving one item at a time (or a small and consistent batch of items) through a series of processing steps as continuously as possible, with each step making just what is requested by the next step.

It is also called the one-piece flow, single-piece flow, and make one, move one.

Continuous Flow Production

Flow with JIT

Traditional Flow

CustomersSuppliers

Customers

Suppliers

Production Process (stream of water)

Inventory (stagnant ponds) Material

(water in stream)

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

Traditional U.S. Manufacturing Firm:Push (“old style” MRP / Material Requirements Planning System)

• The production of items at times required by a given schedule planned in advance

Material Information (Production Schedule)

Work Station 1

WS 2 WS 3

Pull (JIT) System

The production of items only as demanded for use or to replace those taken for use.

Material Information (via Kanban/Card)

Work Station 1

WS 2 WS 3

• Japanese word for card– Pronounced ‘kahn-bahn’ (not ‘can-ban’)

• Authorizes production from downstream operations– ‘Pulls’ material through plant

• May be a card, flag, verbal signal etc.• Used often with fixed-size containers

– Add or remove containers to change production rate

Kanban

Triangular Kanban

Part #

Trigger (Reorder) Point

Part Description Location

Date Triggered Lot Size

Tool #

Machine #

Kanban

Figure S12.5

Basic Fixed-Order Quantity Model and Reorder Point Behavior

R = Reorder pointQ = Economic order quantityL = Lead time

L L

Q QQ

R

Time

Numberof unitson hand

1. You receive an order quantity Q.

2. Your start using them up over time. 3. When you reach down to

a level of inventory of R, you place your next Q sized order.

4. The cycle then repeats.

Kanban

The function of Kanban ≈

The function of Inventory Reorder Point (ROP)

Kanban System• Single card

– Move only containers with C (Conveyance)-kanban)

– e.g.: Kawasaki

• Dual card– Move only container

with C- kanban– Produce only when

authorized by P (Production)- kanban

– e.g.: Toyota

Transparency 17.5

• 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

Inventory

• Reduce ripple effect of small variations in schedules (e.g., final assembly)

• Production quantities evenly distributed over time (e.g., 7/day)

• Build same mix of products every day– Results in many small lots– 1 month = 20 working days– ItemMonthly Quantity Daily Quantity

A 40 2B 60 3

Heijunka = Leveling (Smoothing) Production Schedule using Mixed Model Sequencing

A

A A B B B C

JIT Small Lots

Large-Lot Approach

Time

Time

A A B B B C

A A A B B B B B B C C

JIT produces same amount in same time if setup times are lowered

Small versus Large Lots

Small lots also increase flexibility to meet customer demands

Photo S12.4

40 10 440 10 410 10 1

Heijunka = Leveling (Smoothing) Production Schedule using Mixed Model Sequencing = Uniform Plant Loading

Product Demand RequirementsMonthly Daily

800 20 40800 20 40200 20 10

A

B

CLargest integer that divides into all daily requirements evenly is 10

Product Daily Requirements Divided by 10A

B

CMixed-model sequenceA-B-A-B-A-B-A-B-C Repeat 10 times per day

Transparency 17.7

Determining Production Sequence

Cycle TimesWorking time per day = 480 minutesDaily requirements: A = 40 units; B = 40 units; C = 10 units The system cycle time = 480/(40+40+10) = 5.33 min/unit

Product Requirements Cycle Time480 40 12480 40 12480 10 48

A 40

B 40

C 10

Transparency 17.8

Scrap

Work in process inventory level(hides problems)

Unreliable Vendors Capacity Imbalances

Lowering Inventory Reduces Waste

Scrap

Reducing inventory revealsproblems so they can be solved.

Unreliable Vendors Capacity ImbalancesWIP

Lowering Inventory Reduces Waste

Scrap

Reducing inventory revealsproblems so they can be solved.

Unreliable Vendors Capacity ImbalancesWIP

Lowering Inventory Reduces Waste

Customer orders 10

Lot size = 5Lot 1 Lot 2

Lot size = 2Lot 1 Lot 2 Lot 3 Lot 4 Lot 5

Reducing Lot Sizes Increases the Number of Lots

…Which Increases Inventory Costs

Lot Size

Cost

Holding CostTotal Cost

Setup Cost

Optimal Lot Size

SmallerLot Size

Unless Setup Costs are Reduced

Lot Size

Cost

Holding CostTotal Cost

Setup Cost

Original optimal lot size

New optimal lot size

Quick setup = Quick changeover• Reducing setup cost ≈ reducing setup time• Setup reduction time is a prerequisite to lot size

reduction• SMED (Single Minute Exchange of Dies)

method• The method has been developed by Toyota and

then expanded by Dr. Shigeo Shingo (a consultant to Toyota), and has proven its effectiveness in many companies by reducing changeover times (non-value added times) from hours to a less than 10 minutes

Setup Components

• Internal Setup: consists of setup activities that must be performed while the machine is stopped.

• External Setup: consists of setup activities that can be carried out while the machine is still operating.

It is desirable to:1. Convert as much internal setup to external setup2. Improve the setup procedure

Systematic Setup Reduction

Setup Reduction

Setup Reduction:Standardizing die holder heights reduces the need to

exchange fastening bolts

Setup Reduction Techniques

Quality At The Source

• Doing it right at the first time. • Jidoka allows workers to stop production line• Andon lights signal quality problems• Under capacity scheduling allows for

planning, problem solving & maintenance• Visual control makes problems visible• Poka-yoke prevents defects

House of Toyota

Jidoka• Toyota Production System (TPS) is supported by two pillars: Just-in-Time and Jidoka

• Jidoka = Autonomation = Automation with “human” intelligence.

• Sakichi Toyoda, founder of the Toyota group of companies, invented the concept of Jidoka in the early 20th Century by incorporating a device on his automatic looms that would stop the loom from operating whenever a thread broke. Dr. Shigeo Shingo then developed his idea further.

• This enabled great improvements in quality and freed people up to do more value creating work than simply monitoring machines for quality (separating people’s work and machine’s work).

• Eventually, this simple concept found its way into every machine, every production line, and every Toyota operation.

Jidoka Techniques• Poka-yoke (mistake or error proofing)

– A form of device for building-in quality at each production process.

– This device may take many shapes and designs.

– Typical types of Pokayoke are sensors, proximity switches, stencils, light guards and alignment pins. Simple circuitry is usually used to operate these electrical error proof devices as they should be of low cost and simple design.

– Goal: Finding defects before they occur = Zero Defects

– Statistical Quality Control (SQC): Finding defects after they occur

• Visual management including using Andon Lamp

Poka-Yoke Example

Exhibit 7.10

Visual ManagementAndon Lamp

• Red - line stoppage • Yellow - call for help• Green - normal

operation

Kaizen

• Change for better = continuous improvement

• Kaizen workshop or Kaizen event:A group of Kaizen activity, commonly lasting

five days, in which a team identifies and implements a significant improvement in a process, e.g., creating a manufacturing cell.

GEMBA• GEMBA" is a Japanese word meaning "real place", where

the real action takes place. In business, GEMBA is where the value-adding activities to satisfy the client are carried out.

• Manufacturing companies have three main activities in relation to creating money: developing (designing), producing and selling products. In a broad sense, GEMBA means the sites of these three major activities.

• In a narrower context, however, GEMBA means the place where the products are made.

• The term is often used to stress the that real improvement can only take place when there is a shop-floor focus on direct observation of current conditions where work is done, e.g., not only in the engineering office.

Five Golden Rules of Gemba• Masaaki Imai promoted Kaizen to people outside Japan through his two highly acclaimed books:

1. Kaizen: The Key To Japan's Competitive Success. 2. Gemba Kaizen: A Commonsense, Low-Cost Approach to Management

• He preaches the Five Golden Rules of Gemba, the first of which is 'When a problem (abnormality) arises, go to gemba first'. So what's gemba? It's the shop floor, or equivalent. Once there, you apply

Golden Rule Two: check with gembutsu (relevant objects).

Three: take temporary counter-measures on the spot.

Four: find the root cause.

Five: standardize to prevent recurrence.

Standardization is the managing part of getting good gemba. You also need good housekeeping (Imai is very keen on cleaning machines) and muda, the elimination of waste. But all hinges on getting away from your desk. Obey the master Imai. GO TO GEMBA!

5Whys: Finding the root cause of a problem.

• 5 Whys analysis as an effective problem-solving technique. It is also used in Six Sigma. Example:

• Why is our client, Hinson Corp., unhappy? Because we did not deliver our services when we said we would.

• Why were we unable to meet the agreed-upon timeline or schedule for delivery? The job took much longer than we thought it would.

• Why did it take so much longer? Because we underestimated the complexity of the job.

• Why did we underestimate the complexity of the job? Because we made a quick estimate of the time needed to complete it, and did not list the individual stages needed to complete the project.

• Why didn't we do this? Because we were running behind on other projects. We clearly need to review our time estimation and specification procedures.

Plan-Do-Check-Act(PDCA/Shewart /Deming Cycle)

• Plan: Go to the real place/factory flow (gemba), obverse the real thing/product (gembutsu), get the real fact (genjitsu). Focus on reducing response time, lead times, exposing wastes in your process

• Do: Conduct Kaizen. Create models of excellence so others can aspire to. Flow everything: product, information material replenishment, services.

• Check for direction by aligning activities with long-term business direction

• Act: Take actions to sustain and accelerate improvement activities

Source: www.leanbreakthru.com

Similarity between 3 Gs and MBWA

• The 3 G's (Gemba, Gembutsu, and Genjitsu, which translate into “actual place”, “actual thing”, and “actual situation”).

• In the early days of Hewlett-Packard (H-P), Dave Packard and Bill Hewlett devised an active management style that they called Management By Walking Around (MBWA). Senior H-P managers were seldom at their desks. They spent most of their days visiting employees, customers, and suppliers. This direct contact with key people provided them with a solid grounding from which viable strategies could be crafted.

5S: Workplace organization/Housekeeping• 5s: Important part of Kaizen/Lean Manufacturing• The S's stand for:

– Seiri - keep only what is absolutely necessary, get rid of things that you don't need, i.e. simplify or sort.

– Seiton - create a location for everything, i.e. organizeor straighten.

– Seiso - clean everything and keep it clean, i.e. cleanliness or sweep.

– Seiketsu - implement Seiri, Seiton and Seiso plant wide, i.e. standardize.

– Shitsuke - assure that everyone continues to follow the rules of 5S, i.e. stick to it or self discipline.

• 5S in the US: Sort, Straighten, Sweep, Standardize, Self Disciple

• 5S + 1S (Safety) = 6S (Hytrol, etc)• 5S + 2S (Safety and Security) = 7 S (Agilent Technology that was part

of Hewlett Packard)

5S• 5S is simple to begin and gives good benefits.

• Each individual in an organization is asked to get rid of overburdening items.

• Red tag attack: A red tag attack is the strategy of a group of people going through the plant and putting red tags on everything that has not been used within the last 30 days. The items that people feel are necessary to "hold on to" must be justified to their superior, or the item is taken out of the plant!

5S in a Factory

Factory tour: Toyota vs. others.

5S in Office• Before 5 S

• After 5 S

Standard Work

When manpower, equipment, and materials are used in the most efficient combination, this is called Standard Work.

There are three elements to Standard Work:

1) Takt Time

2) Work Sequence

3) Standard Work-in-Process

Once a Standard Work is set, performance is measured and continuously improved.

Standard Work Sheet

Scope of From Raw materi al Date Reviewed:

Operations To Heat Treatment Janary 7, 2000

Quality Safety Standard Work Standard WIP TAKT Cycle CrewCheck Precaution in Process Quantity Time Time Size

FG

223.4 min12.1 min10

RM

The Importance of Standardized Work:

Without it, all improvement efforts using Kaizen to eliminate waste (muda) are not sustainable. You will go back to the original position before Kaizen.

Manufacturing Cell

Worker Routes Lengthened as Volume Decreases

Cell 5Cell 5

Worker Worker 22

Cell 2Cell 2

Worker Worker 11

Cell 1Cell 1

Worker Worker 33

Cell 3Cell 3 Cell 4Cell 4

Figure 11.4Figure 11.4

Workload balancing

• Aims at maximizing operator utilization based on the given takt time.

• Is the key to adjust JIT lines to demand fluctuations

• Requires flexible operators

Production Line Balancing

Improving Lead Time:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Current SituationPercent of Lead Time

5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100

Approach # 1: Reducing Value Added (VA) Time by 50%

VA

Approach # 2: Reducing Non Value Added (VA) Time by 50%

NVA (Non Value Added)

NVA

NVA

VA

VA

Value Stream MappingSM

What?

Why?

Who?

When?

Where?

How?

• A visual tool for identifying all activities of the planning, and manufacturing process to identify waste.

• Provides a tool to visualize what is otherwise usually invisible.

• The leaders of each product family need to have a primary role in developing the maps for their own area.

• Develop a current-state map before improvements are made so that the efforts and benefits can be quantified.

• On the shop floor, not from your office. You need the real information, not opinion or old data.

• Next page

Value Stream Map Symbols Spot weld

ABCplating

C/T = 30 sec

C/O = 10 min

3 shifts

2% scrap rate

Process

Finishedgoods

Vendor Data box

3,000 units

= 1 day

Inventory

Push Supermarket: the location of a predetermined

standard inventory

Physical pull

Monand

Wed

Shipment

C/T = Cycle Time

C/O = Change over or setup time

Current Value Stream Map

Future Value Stream Map

Attributes of Lean Producers - they• use JIT to eliminate inventory• build systems to help employees product a perfect part every

time• reduce space requirements• develop close relationships with suppliers• educate suppliers• eliminate all but value-added activities• develop the workforce• make jobs more challenging• reduce the number of job classes and build worker flexibility• apply Total Productive Maintenance (TPM)

The Five Steps of Lean Production/Toyota Production

System Implementation• Step 1: Specify Value

Define value from the perspective of the final customer. Express value in terms of a specific product, which meets the customer's needs at a specific price and at a specific time.

• Step 2: Value Stream Mapping.Identify the value stream, the set of all specific actions required to bring a specific product through the three critical management tasks of any business: the problem-solving task, the information management task, and the physical transformation task. Create a map of the Current State and the Future State of the value stream. Identify and categorize waste in the Current State, and eliminate it!

• Step 3: Create Continuous FlowMake the remaining steps in the value stream flow. Eliminate functional barriers and develop a product-focused organization that dramatically improves lead-time.

• Step 4: Create Pull ProductionLet the customer pull products as needed.

• Step 5: PerfectionThere is no end to the process of reducing effort, time, space, cost, and mistakes. Return to the first step and begin the next lean transformation, offering a product which is ever more nearly what the customer wants.

Comparison ofMRP (Material Requirements Planning),

JIT, and TOC (Theory of Constraints)

Loading of operations

Batch sizes

Importance of dataaccuracySpeed of scheduleddevelopmentFlexibilityCostGoals

Planning focusProduction basis

Checked by capacityrequirementsPlanning afterwardOne week or more

Critical

Slow

LowestHighestMeet demandHave doable planMaster schedulePlan

Controlled by kanbansystem

Small as possible

Unnecessary

Very fast

HighestLowestMeet demandEliminate wasteFinal assembly scheduleNeed

Controlled bybottleneck operation

Variable to exploitconstraintCritical for bottleneckand feeder operations

Fast

ModerateModerateMeet demandMaximize profitsBottleneckNeed and plan

MRP JIT TOC