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Just-in-Time (JIT)

JIT philosophy means getting the right quantity of goods at the right place and the right time

JIT exceeds the concept of inventory reduction; it is an all-encompassing philosophy geared to eliminate waste, anything that does not add value

A broad JIT view – or lean production/lean systems – is one that encompasses the entire organization

Just-in-Time (JIT) and Lean Systems

Philosophy of JIT

JIT originated in Japan at Toyota Motor Co, fueled by a need to survive the devastation post WWII

JIT gained worldwide prominence in the 1970s

Often termed “Lean Production” or “Lean Systems”

Broad view that entire organization has the same goal – to serve customers

Just-in-Time (JIT) and Lean Systems

Philosophy of JIT – cont'd

Everyone should have a broad view of the organization and work toward the same goal, which is serving the customer

JIT is built on simplicity – simpler is better

Continuous improvement – often using kaizen blitz

Visibility – all waste must be visible to be identified and eliminated

Flexibility – to adapt to changes in environment

Just-in-Time (JIT) and Lean Systems

Three Elements of JIT

Just-in-Time (JIT) and Lean Systems

Three Elements of JIT – cont'd

JIT manufacturing

focuses on production system to achieve value-added manufacturing

TQM

is an integrated effort designed to improve quality performance at every level

Respect for people

rests on the philosophy that human resources are an essential part of JIT philosophy

Just-in-Time (JIT) and Lean Systems

Elements of JIT Manufacturing

JIT Manufacturing is a philosophy of value-added manufacturing

Achieved by focusing on these elements:

Inventory reduction – exposes problems

Kanbans & pull production systems

Small lots & quick setups

Uniform plant loading

Flexible resources

Efficient facility layouts

Just-in-Time (JIT) and Lean Systems

Role of Inventory Reduction

Inventory = Lead Time (less is better)

Inventory hides problems

Just-in-Time (JIT) and Lean Systems

JIT Manufacturing: The Pull System

Just-in-Time (JIT) and Lean Systems

Number of Kanbans Required

N = number of containers

D = demand rate at the withdraw station

T = lead time from supply station

C = container size

S = safety stock

Just-in-Time (JIT) and Lean Systems

Computing the Number of Kanbans: an aspirin manufacturer has converted to JIT manufacturing using kanban containers. They must determine the number of containers at the bottle filling operation which fills at a rate of 200 per hour. Each container holds 25 bottles, it takes 30 minutes to receive more bottles, safety stock is 10% of demand during LT.

Tip: round up = would provide additional slack

round down = need to make improvements in operations

Click to edit Master text styles

Second level

Third level

Fourth level

Fifth level

Variations on Kanban Production

Just-in-Time (JIT) and Lean Systems

Kanban boxes

space on factory floor for storing supplies

Flags (signal kanban)

used to indicate when supplies need to be ordered

Supplier kanbans

brings filled containers to point of usage in factory/picks up empty containers

Small Lot Sizes & Quick Setups

Small lots mean less average inventory and shorten manufacturing lead time

Small lots with shorter setup times increase flexibility to respond to demand changes

Strive for single digit setups- < 10 minutes

Setup reduction process is well-documented

External setup- do as much preparation while present job is still running; thus can be performed while machine is still running

Internal setup- simplify, eliminate, shorten steps involved with location, clamping, & adjustments; requires the machine to be stopped in order to be performed

Ultimate goal is single unit lot sizes

Just-in-Time (JIT) and Lean Systems

Uniform Plant Loading

A “level” schedule is developed so that the same mix of products is made every day in small quantities

Leveling the schedule can have big impact along whole supply chain

Just-in-Time (JIT) and Lean Systems

Flexible Resources

Moveable, general purpose equipment:

Portable equipment with plug in power/air

Drills, lathes, printer-fax-copiers, etc.

Capable of being setup to do many different things with minimal setup time

Multifunctional workers:

Workers assume considerable responsibility

Cross-trained to perform several different duties

Trained to also be problem solvers

Just-in-Time (JIT) and Lean Systems

Effective Facility Layouts

Workstations in close physical proximity to reduce transport & movement

Streamlined flow of material

Often use:

Cellular Manufacturing

Placement of dissimilar machines and equipment together to produce a family of products with similar processing requirements

U-shaped lines

allows material handler to quickly drop off materials & pick up finished work; flexibility

Just-in-Time (JIT) and Lean Systems

BUS 363 – Production Operations Management

Improving Layouts Using Work Cells

BUS 363 – Production Operations Management

Improving Layouts Using Work Cells

TQM

Product versus process

Quality in JIT is centered on building quality into the process

Quality at the source – sequential inspection

Jidoka – authority to stop line

Poka-yoke – fail-safe all processes

Just-in-Time (JIT) and Lean Systems

TQM

Preventative Maintenance

Regular inspections and maintenance to keep machines operational

Costly, yes but less expensive than unexpected machine breakage.

Work environment

perform maintenance as part of their regular work

Care of equipment and well-trained workers are very important.

Just-in-Time (JIT) and Lean Systems

Respect for People

The Role of Employees:

Genuine and meaningful respect for employees

Willingness to develop cross-functional skills

Associates gather performance data; make production and quality decisions

Bottom-round management

consensus management by committees or teams

Quality circles

small volunteer teams that solve quality problems

Everyone is responsible for Quality and preventive maintenance

Just-in-Time (JIT) and Lean Systems

Respect for People – cont’d

Lifetime Employment:

Everyone feels secure/is empowered

Everyone is responsible for quality: understand both internal and external customer needs

Just-in-Time (JIT) and Lean Systems

Respect for People cont’d

The Role of Management:

Responsible for culture of mutual trust

Serve as coaches & facilitators

Responsible for developing workers

Provide multi-functional training

Facilitate teamwork

Support culture with appropriate incentive system including non-monetary

Just-in-Time (JIT) and Lean Systems

Respect for People – cont’d

Supplier Relationships:

Single-source suppliers

Can supply entire family of parts; external factory

Build long-term relationships with small number of suppliers

Suppliers locate near customer

Fewer contracts

Cost and information sharing

Work together to certify processes

Just-in-Time (JIT) and Lean Systems

Benefits of JIT

Reduction in inventories

Improved quality

Reduced space requirements

Shorter lead times

Lower production costs

Increased productivity

Increased machine utilization

Greater flexibility

Just-in-Time (JIT) and Lean Systems

Implementing JIT

Starts with a company shared vision of where it is and where it wants to go

Management needs to create the right atmosphere

Implementation needs a designated “Champion”

Just-in-Time (JIT) and Lean Systems

Implementing JIT – cont'd

Implement the sequence of seven steps:

Make quality improvements

Reorganize workplace

Reduce setup times

Reduce lot sizes & lead times

Implement layout changes

Switch to pull production

Develop relationship with suppliers

Just-in-Time (JIT) and Lean Systems

JIT in Services

Many JIT concepts also apply to Service companies

Improved quality such as timeliness, service consistency, and courtesy

Uniform facility loading to provide better service responsiveness

Use of multifunction workers

Reduction in cycle time

Minimizing setup times and parallel processing

Workplace organization

Just-in-Time (JIT) and Lean Systems

JIT & Lean Systems: How it all Fits Together

JIT: an overriding philosophy that affects all other business decisions

Quality improvements (chs 5 & 6)

Partnering with suppliers (ch 4)

Changing job designs (ch 11)

Facility layout (ch 10)

Changes in production process (ch 3)

Changes in inventory (ch 12)

Just-in-Time (JIT) and Lean Systems

JIT Across the Organization

JIT eliminates organizational barriers and improves communications

Accounting changes or relies on activity-based costing

Marketing by interfacing with the customers

Finance approves and evaluates financial investments

Information systems create the network of information necessary for JIT to function

Just-in-Time (JIT) and Lean Systems

down?

round

Question

containers

kanban

4.4

(200)(.5)

bottles

.5)

0.10(200)(

d)(T)

0.10(deman

container

per

bottles

hour

minutes

hour

per

bottles

200

Solution