Chapter 13- JIT/Lean
Kanbans
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Recent Developments in Lean Thinking
1. Lean Six Sigma 2. Lean Supply Chain Management
Eight Commonly Recognized sources of waste
1. Overproduction 2. Waiting 3. Unnecessary Transportation 4. Inappropriate Process 5. Unnecessary Inventory 6. Unnecessary/excess Motion 7. Defects 8. Underutilization of employees
Kanban System,
1. Pull System 2. Other Signaling Methods
Summary of Kanban System
A downstream station pulls finished material out of work center B - Work center B pulls raw material into production - Demand for more raw material in work center B pulls finished material out of work center A
1. Move Card
A kanban card that is used to indicate when a container of parts should be moved to the next process step
2. Production Card
A kanban card that is used to indicate when another container of parts should be produced
1. Lean Six Sigma
A methodology that combines the organizational elements and tools of Six Sigma with Lean's focus on waste reduction
Just-in-Time (JIT)
A philosophy of manufacturing based on planned elimination of all waste and on continuous improvement of productivity. In a broad sense, it applies to all forms of manufacturing and to many service industries as well
Lean
A philosophy or production that emphasizes the minimization of the amount of all the resources (including time) used in the various activities of an enterprise. It involves identifying and eliminating non-value-adding activities in design, production, supply chain, management, and dealing with customers
Kanban System
A production control approach that uses containers, cards, or visual cues to control the production and movement of goods through the supply chain Key Characteristics: - Uses simple signaling mechanisms to indicate when specific items should be produced or moved - Can be used to synchronize activities either within a plant or between different supply chain partners - Are not considered planning tools, but rather control mechanisms that are designed to pull parts or goods through the supply chain based on downstream demand
1. Pull system
A production system in which actual downstream demand sets off a chain of events that pulls material through the various process steps - A kanban system is also called a pull system
Two-Card Kanban System
A special form of the Kanban system that uses on card to control production and another card to control movement of materials 1. Move Card 2. Production card
The Perspective on Inventory.
After a successful Lean program has been put in place, wasted movement and space are eliminated and work centers are moved closer together - Inventory levels are reduced dramatically and work center make only what is needed when it is needed
2. Lean Supply Chain Management
An extension of the Lean philosophy to supply chain efforts beyond production. Lean Supply Chain Management seeks to minimize the level of resources required to carry out all supply chain activities
Waste
Any activity that does not add value to the good or service in the eyes of the consumer - Called "muda" in Japanese - Started with Taiichi Ohno, a Toyota engineer
4. Inappropriate Process
Companies sometimes use overly complex processes when simpler, more efficient ones would do
Synchronizing the Supply Chain Using Kanbans
For a kanban system to work properly, there must be a smooth, consistent flow of material through the links
Inventory Hides Problems
High inventory levels "hide" problems... while lowering inventory exposes problems
2. Waiting
Inefficient layouts or an inability to match demand without output levels may cause waitin
1. Overproduction
Inflexible or unreliable processes may cause organizations to produce goods before they are required
7. Defects
Not only do defects create uncertainty in the process, they rob production capacity by creating products or services that require rework or must be scrapped
6. Unnecessary/excess Motion
Poorly designed processes can lead to unnecessary motion
2. Other Signaling Methods
Single-card systems, where the single card is the production card and the empty container serves as the move signal - Color coding of containers - Designated Storage Spaces - Computerized bar-coding system
Lean Pt 2.
The Lean philosophy can be applied to a wide range of production and service environments - Companies following the Lean philosophy can and do use a wide range of planning and control techniques, not just kanban - The Lean philosophy is entirely consistent with business process improvement, quality improvement, and supplier management initiatives
8. Underutilization of employees
This is the newest form of waste added to the list, and it recognized that too often companies do not fully utilize the skills and decision-making-capabilities of their employees
3. Unnecessary Transportation
Transporting goods always increases costs and the risk of damage, but it does not necessarily provide value to the final customer
The Perspective on Inventory
Triangle represent inventory between work centers A, B and C - The buildup of inventory hides the problems that may occur but at a cost
5. Unnecessary Inventory
Uncertainty with regard to quality levels, delivery lead times, and the like can lead to unnecessary inventory
Controlling Inventory Levels Using Kanbans
y = DT (1+x) / C