Ch 14: JIT and Lean Operations

Lean Operations:

A flexible system of operation that uses considerably fewer resources than a traditional system

• introduced by Toyota

Just-In-Time JIT:

A method used in lean operations in which goods move through the system, and services are performed, just as they are needed.

Lean System Principles: (5)

1. identify customer value

2. focus on processes that create value

3. eliminate waste to create flow

4. produce only according to customer demand

5. strive for perfection

Key Benefits of Lean System:

• increased productivity

• reduced waste

• lower costs

• increased quality

• reduced cycle time

Critical Risks of Lean Systems:

1. Increased stress on workers

2. Fewer resources are available if problems occur

3. supply chain disruptions that can halt operations

Ultimate Goal of Lean Systems:

• a balanced system with smooth, rapid flow of materials and/or work through the system, making process time as short as possible by using resources effectively

Supporting Goals of Lean Systems:

1. eliminate disruptions

2. make the system flexible

3. eliminate waste

8 Wastes in Lean System:

• waste (MUDA) → unproductive resources

1. excess inventory

2. overproduction

3. waiting time

4. unnecessary transporting

5. processing waste/scrap

6. inefficient work methods

7. product defects/rework

8. underused people

Lean Production System Building Blocks

Product Design:

1. standard parts- common, interchangeable

2. modular design- module: a cluster of parts

3. highly capable systems w/ quality built in

4. concurrent engineering- different functions/design teams work together simultaneously

Lean Production System Building Blocks

Process Design:

1. small lot sizes

2. setup time reduction

3. manufacturing cells

4. quality improvement

5. production flexibility

6. a balanced system

7. little inventory storage

8. fail-safe method

Lean Production System Building Blocks

Personnel/organizational elements:

1. workers as assets

2. cross-trained workers

3. continuous improvement

4. cost accounting/activity-based costing

5. leadership/project management

Lean Production System Building Blocks

Manufacturing Planning and Control (MPC):

• level loading

• pull systems

• visual systems

• limited WIP

• close vendor relationships

• reduced transaction processing

• preventive maintenance/housekeeping

Key Learn Terms

Small Lot Sizes:

• reduce inventory and carrying costs

• reduce rework

• increase visibility of problems

• improve flexibility

• help balance operations

Key Learn Terms

Autonomation (jidoka)

Automatic detection of defects during production

• supports quality improvement.

Key Learn Terms

Task Time:

The maximum time allowed to produce one unit to meet customer demand - the target rhythm of the system.

• Cycle time is the actual time the process takes

Key Learn Terms

Push System:

Output is pushed to the next station when work is finished.

Key Learn Terms

Pull System:

Each workstation pulls output from the preceding station as needed

Key Learn Terms

Kanban

• A signal or visible record authorizing movement or production.

• Production kanban signals the need to produce

• Conveyance kanban signals the need to deliver parts

Key Learn Terms

Limited WIP

• Kanban controls WIP at individual workstations

• CONWIP controls total WIP in the overall system and can be useful when variability is present.

Key Learn Terms

Housekeeping (5S’s)

1. Sort

2. Straighten

3. Sweep

4. Standardize

5. Self-discipline