Kanban for the Shopfloor

Productivity Press Development Team

• Editore: Productivity Press
• Anno: 2020
• ISBN:
  9781000170160
• Edizione: 1
• Argomento: Business
• Categoria: Industrial Management

Kanban is the name given to the inventory control card used in a pull system. The primary benefit of kanban is to reduce overproduction, the worst of the seven deadly wastes. A true kanban system produces exactly what is ordered, when it is ordered, and in the quantities ordered. It is essentially a dynamic work order that moves with the material.

Each kanban identifies the part or subassembly unit and indicates where each one came from and where each is going. Used this way, kanban acts as a system of information that integrates your plant, connects all processes one to another, and connects the entire value stream to customer demand.

Kanban for the Shopfloor provides a working manual for those seeking to implement this method of production control in any operation. It defines the various terms and methods employed in kanbans, and illustrates how when adhered to, kanban is an element of continuous improvement that ultimately leads to the ideal of one-piece flow."

In addition to reducing the waste of overproduction, kanban will help your company increase flexibility to respond to customer demand, coordinate production of small lots and wide product variety, and simplify the procurement process.

About the Shopfloor Series: Put proven improvement tools in the hands of your entire workforce!

Progressive shopfloor improvement techniques are imperative for manufacturers who want to stay competitive and to achieve world class excellence. And it's the comprehensive education of all shopfloor workers that ensures full participation and success when implementing new programs. The Shopfloor Series books make practical information accessible to everyone by presenting major concepts and tools in simple, clear language and at a reading level that has been adjusted for operators by skilled instructional designers. One main idea is presented every two to four pages so that the book can be picked up and put down easily. Each chapter begins with an overview and ends with a summary section. Helpful illustrations are used throughout.

Other topics in the Shopfloor Series: Kanban, 5S, Quick Changeover, Mistake-Proofing, Just-in-Time, TPM, Cellular Manufacturing

Chapter 1

Introducing Key Terms and Benefits of Kanban

CHAPTER OVERVIEW

What Is Kanban?

The Pull System and Waste Reduction

What Will Make Kanban Successful?

Integrating Kanban with MRPII

Pilot or Plantwide Implementation

How Will Kanban Change What You Are Doing Now?

What Are the Benefits of Kanban?

Kanban and Your Company

Kanban and You

In Conclusion

Summary

Reflections

Figure 1-1. A Typical Kanban Card

What Is Kanban?

The kanban system determines the production quantities in every process. It has been called the nervous system of lean production because it manages production just as our brains and nerves manage our bodies. The primary benefit of the kanban system is to reduce overproduction; and its aim is to produce only what is ordered, when it is ordered, and in the quantities ordered.

In Japanese, the word “kanban” means “card” or “sign” and is the name given to the inventory control card used in a pull system. It is essentially a work order that also moves with the material. Each card or kanban identifies the part or subassembly unit and indicates where each came from and where each is going. Used this way, kanban acts as a system of information that integrates the plant, connects all processes one to another, and connects the entire value stream to the customer demand harmoniously.

The Pull System and Waste Reduction

In the kanban system the upstream process produces only enough units to replace those that have been withdrawn by the downstream process. Workers in one process go to the preceding process to withdraw the parts they need. They do this only in the quantities and at the time when the units are needed. The start of this withdrawal system begins with a customer order. This is called a pull system.

Figure 1-2. Pull Production with Kanban

The pull system is based on the concept of a supermarket. In a supermarket, customers buy products already on the shelves and the shelves are replenished as customers remove the products from the shelf. Applied to lean production, this process reverses the large lot “push” method of producing products based on an estimate of expected sales.

A pull system creates flexibility on the production floor so that exactly what has been ordered will be produced, when it is ordered, and only in the quantities ordered. In this way, it is possible to eliminate overproduction — the most critical of the seven deadly wastes. The ultimate conceptual goal is zero kanban, which eliminates work-in-process inventory. In other words, your customer order becomes the signal for a pure continuous flow. It is the ideal that the spirit of continuous improvement in a pull system always strives toward. Reducing kanbans will be discussed in Chapter 5.

TAKE FIVE

Take five minutes to think about these questions and to write down your answers:

1. What are two other words for kanban and how is a kanban used?

2. What are some advantages of a pull system?

What Will Make Kanban Successful?

Kanban is best implemented when a company has committed to a pull production system and has already implemented small-lot production through one-piece flow and cellular manufacturing. Once these methods are in place, kanban is the communication system that keeps all the cells integrated and working in harmony. If kanban is deployed only in parts of the plant there may be confusion between the “push” and “pull” aspects of the production system. Kanban will expose the problems that cause waste, such as overproduction, and if a pull system is not the plant’s ultimate goal it may become difficult to eliminate these problems. If a company has wide fluctuations in demand that cannot be smoothed (such as seasonal products) and therefore will not benefit from small-lot production, kanban will be less effective and may be inappropriate. To learn about cellular manufacturing and one-piece flow see Productivity’s shopfloor book, Cellular Manufacturing: One-Piece Flow for Workteams.

As the number of kanbans in the system is gradually reduced, the first problems that surface are usually changeover bottlenecks. Improvement methods must be used immediately to reduce changeover times so that takt time can be reestablished and a mixed, small-lot production flow can continue to be regulated by kanbans. If methods for reducing changeover times are not being practiced it will be impossible for the plant to respond to customer demand, which is the key purpose of kanban and the pull system. Quick changeover is discussed fully in Productivity’s shopfloor book, Quick Changoever for Operators: The SMED System.

Autonomous maintenance is another critical element to insure a successful pull production system. Keeping machines operating, planning scheduled maintenance, and all the other elements of total productive maintenance ultimately will be necessary for kanban to function optimally. Our Autonomous Maintenance for Operators shopfloor book will help you implement this lean method.

Kanban is an advanced visual control system and depends on the discipline and understanding that grow from implementing the 5S. The steps toward creating a visual workplace — beginning with 5S to put the workplace in order, establish visual displays, and support continuous improvements (which are initiated by each and every operator) — will be an important foundation for your pull system implementation. The steps of 5S are fully discussed in Productivity’s 5S for Operatars: 5 Pillars of the Visual Workplace. Chapter 5 of this book includes a discussion of kanban as a visual control system.

TAKE FIVE

Take five minutes to think about these questions and to write down your answers:

1. How many of these lean production methods do you currently use in your plant?

2. What else can you do to prepare your workplace for the kanban system?

Integrating Kanban with MRPII

Many books have been written discussing ways to integrate a material requirements planning system with kanban. We will not address this approach here. MRPII is a computerized system for estimating future production needs rather than responding to customer demand as it occurs. In other words it was designed for use in “push” systems. Where some companies may choose to move gradually toward a pull system by integrating their existing MRPII method with kanban, the focus of this book is to show the kanban system in its purest form as the mechanism for implementing true “pull” production.

Pilot or Plantwide Implementation

It is important to decide where kanban will be implemented — throughout the plant or only in pilot areas. Remember, kanban is a system that integrates the process...