JIT and Lean Operations

JIT and Lean OperationsJIT and Lean Operations

Group Members:

JIT/Lean ProductionJIT/Lean Production

Just-in-time (JIT): A highlycoordinated processing system in whichgoods move through the system, andservices are performed, just as they areneeded,

JIT   lean production

JIT  pull (demand) system

JIT operates with very little “fat”

Goal of JITGoal of JIT

The ultimate goal of JIT is a balancedsystem.

Achieves a smooth, rapid flow of materialsthrough the system

Summary JIT Goals and BuildingBlocksSummary JIT Goals and BuildingBlocks

Product

Design

Process

Design

Personnel

Elements

Manufactur-ing Planning

Eliminate disruptions

Make the system flexible

Eliminate waste

balanced

rapid flow

Ultimate

Goal

Supporting

Goals

Building

Blocks

Supporting GoalsSupporting Goals

Eliminate disruptions

Make system flexible

Eliminate waste, especially excessinventory

Sources of WasteSources of Waste

Overproduction

Waiting time

Unnecessary transportation

Processing waste

Inefficient work methods

Product defects

Big vs. Little JITBig vs. Little JIT

Big JIT – broad focus

◦Vendor relations

◦Human relations

◦Technology management

◦Materials and inventory management

Little JIT – narrow focus

◦Scheduling materials

◦Scheduling services of production

JIT Building BlocksJIT Building Blocks

Product design

Process design

Personnel/organizationalelements

Manufacturingplanning and control

Product DesignProduct Design

Standard parts

Modular design

Highly capable production systems

Concurrentengineering

Process DesignProcess Design

Small lot sizes

Setup time reduction

Manufacturing cells

Limited work in process

Quality improvement

Production flexibility

Little inventory storage

Benefits of Small Lot SizesBenefits of Small Lot Sizes

Reduces inventory

Less rework

Less storage space

Problems are more apparent

Increases product flexibility

Easier to balance operations

Production FlexibilityProduction Flexibility

Reduce downtime by reducingchangeover time

Use preventive maintenance to reducebreakdowns

Cross-train workers to help clearbottlenecks

Use many small units of capacity

Use off-line buffers

Reserve capacity for important customers

Quality ImprovementQuality Improvement

Autonomation

◦Automatic detection of defects duringproduction

Jidoka

◦Japanese term for autonomation

Personnel/Organizational ElementsPersonnel/Organizational Elements

Workers as assets

Cross-trained workers

Continuousimprovement

Cost accounting

Leadership/projectmanagement

Manufacturing Planning and ControlManufacturing Planning and Control

Level loading

Pull systems

Visual systems

Close vendor relationships

Reduced transactionprocessing

Preventive maintenance

Pull/Push SystemsPull/Push Systems

Pull system: System for moving workwhere a workstation pulls output from thepreceding station as needed. (e.g. Kanban)

Push system: System for moving workwhere output is pushed to the next stationas it is completed

Kanban Production Control SystemKanban Production Control System

Kanban: Card or other device thatcommunicates demand for work ormaterials from the preceding station

Kanban is the Japanese word meaning“signal” or “visible record”

Paperless production control system

Authority to pull, or produce comesfrom a downstream process.

Kanban FormulaKanban Formula

DT(1+X)

N = Total number of containers

D = Planned usage rate of using work center

T = Average waiting time for replenishment of parts plus average production time for a container of parts

X = Policy variable set by management - possible inefficiency in the system

C = Capacity of a standard container

Traditional Supplier NetworkTraditional Supplier Network

Buyer

Supplier

Tiered Supplier NetworkTiered Supplier Network

Supplier

Buyer

Supplier

First Tier SupplierFirst Tier Supplier

Second Tier SupplierSecond Tier Supplier

Third Tier SupplierThird Tier Supplier

Comparison of JIT and TraditionalComparison of JIT and Traditional

Factor

Traditional

JIT

Inventory

Much to offset forecasterrors, late deliveries

Minimal necessary to operate

Deliveries

Few, large

Many, small

Lot sizes

Large

Small

Setup; runs

Few, long runs

Many, short runs

Vendors

Long-term relationshipsare unusual

Partners

Workers

Necessary to do the work

Assets

Transitioning to a JIT SystemTransitioning to a JIT System

Get top management commitment

Decide which parts need most effort

Obtain support of workers

Start by trying to reduce setup times

Gradually convert operations

Convert suppliers to JIT

Prepare for obstacles

Obstacles to ConversionObstacles to Conversion

Management may not be committed

Workers/management may not becooperative

Suppliers mayresist

◦ Why?

JIT in ServicesJIT in Services

The basic goal of the demand flow technologyin the service organization is to provideoptimum response to the customer with thehighest quality service and lowest possiblecost.

◦Eliminate disruptions

◦Make system flexible

◦Reduce setup and lead times

◦Eliminate waste

◦Minimize WIP

◦Simplify the process

JIT II: a supplier representative worksright in the company’s plant, making surethere is an appropriate supply on hand.

JIT IIJIT II

Benefits of JIT SystemsBenefits of JIT Systems

Reduced inventory levels

High quality

Flexibility

Reduced lead times

Increased productivity

Benefits of JIT Systems (cont’d)Benefits of JIT Systems (cont’d)

Increased equipment utilization

Reduced scrap and rework

Reduced space requirements

Pressure for good vendor relationships

Reduced need for indirect labor

Smooth flow of work (the ultimate goal)

Elimination of waste

Continuous improvement

Eliminating anything that does not addvalue

Simple systems that are easy to manage

Use of product layouts to minimizemoving materials and parts

Quality at the source

Elements of JITElements of JIT

Poka-yoke – fail safe tools and methods

Preventative maintenance

Good housekeeping

Set-up time reduction

Cross-trained employees

A pull system

Elements of JIT (cont’d)Elements of JIT (cont’d)

Thank You!Thank You!