This document discusses the principles and elements of Just-in-Time (JIT) and Lean manufacturing systems. It explains that JIT aims to eliminate all waste through approaches like reducing inventory, implementing pull-based production, setting up small lot sizes and quick changeovers, uniformly leveling plant workload, utilizing flexible resources, and designing effective facility layouts. The roles of quality management, employees, management, and suppliers in supporting JIT are also outlined. Benefits of JIT include smaller inventories, shorter lead times, improved quality, and reduced costs.
2. Chapter 7 – Just-in-Time
and
Lean Systems
Operations Management
by
R. Dan Reid & Nada R. Sander
3. Just-In-Time (JIT)
JIT is an all-encompassing
manufacturing and service
management philosophy that is founded
on the concept of elimination of waste.
The term just-in-time stems from a
primary form of waste elimination:
reducing inventories (in manufacturing)
and waiting times (in services).
4. Waste Elimination
Waste is anything that doesn’t add
value. Examples:
Time wasted due to unsynchronized
production
Excessive inventories
Unnecessary material handling due to
poorly designed layouts
Scrap & rework due to poor quality
6. The Philosophy of JIT
Often termed “Lean Systems”
All waste must be eliminated
Broad view that entire organization must focus on
serving customers
JIT is built on simplicity- the simpler the better
Focuses on improving every operation- Kaizen
Install simple visible control systems
Flexibility to produce different models/features
7. Elements of JIT Manufacturing
Inventory reduction exposes problems
Kanbans & pull production systems
Small lots & quick setups
Uniform plant loading
Flexible resources
Efficient facility layouts
10. 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 tasks- do as much preparation while
present job is still running
Internal tasks- simplify, eliminate, shorten steps
involved with location, clamping, & adjustments
11. 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
Monday Tuesday Wednesday Thursday Friday
AAAAA BBBBB BBBBB DDDDD EEEEE
AAAAA BBBBB BBBBB CCCCC EEEEE
Monday Tuesday Wednesday Thursday Friday
AABBBB AABBBB AABBBB AABBBB AABBBB
CDEE CDEE CDEE CDEE CDEE
5 units
5 units
10 units
Weekly Production Required
Traditional Production Plan
JIT Plan with Level Scheduling
A
B
C
D
E
10 units
20 units
12. Flexible Resources
Moveable, general purpose equipment:
Portable equipment with plug in power/air
E.g.: 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
13. Effective Facility Layouts
Workstations in close physical proximity to
reduce transport & movement
Streamlined flow of material
Often use:
Cellular Manufacturing (instead of process
focus)
U-shaped lines: (allows material handler to
quickly drop off materials & pick up finished work)
15. JIT Cellular Manufacturing
Product focused cells, flexible equipment, high
visibility, easy to schedule, short cycles
16. JIT and TQM- Partners
Build quality into all processes
Focus on continuous improvement - Kaizen
Quality at the source- sequential inspection
Jidoka (authority to stop line)
Poka-yoke (fail-safe all processes)
Preventive maintenance- scheduled
Work environment- everything in its place, a
place for everything
17. Respect for People: The Role of
Employees
Genuine and meaningful respect for associates
Willingness to develop cross-functional skills
Actively engage in problem-solving (quality circles)
Everyone is empowered
Everyone is responsible for quality: understand both
internal and external customer needs
Associates gather performance data
Team approaches used for problem-solving
Decisions made from bottom-up
Everyone is responsible for preventive maintenance
18. The Role of Management
Responsible for culture of mutual trust
Serve as coaches & facilitators
Support culture with appropriate incentive
system including non-monetary
Responsible for developing workers
Provide multi-functional training
Facilitate teamwork
19. Supplier Relationships and JIT
Use single-source suppliers when possible
Build long-term relationships
Work together to certify processes
Co-locate facilities to reduce transport if possible
Stabilize delivery schedules
Share cost & other information
Early involvement during new product designs
20. Benefits of JIT
Smaller inventories
Shorter lead times
Improved quality
Reduced space requirements
Lower production costs
Increased productivity
Greater flexibility
21. JIT in Services
Most of the JIT concepts apply equally to
Service companies
Cellular layouts, product focused, & flexible
employees shorten response times
Service inventory, “paperwork”, should be
eliminated, simplified, examined for “waste”
“Fail-safe” all processes from Orders-
Payment
Team based organizations