Learning from ‘Lean’

You may have heard a lot about Lean Manufacturing, but little about how to apply the principles of Lean thinking in the maintenance process. This new series, exclusive to Machinery & Equipment MRO, will show you how to introduce lean practices into maintenance operations.

The Lean Maintenance column will appear every issue this year and will provide a basic insight to the world of “Lean.” First up is an overview of Lean Manufacturing philosophies and the terms and techniques that separate it from other continuous improvement processes.

Although the term “Lean Manufacturing” is relatively new (it was first used in the 1990 book The Machine That Changed The World by James Womack and Daniel Roos), the concept has been around for almost 50 years.

In the 1950s, Toyota was looking for ways to stay competitive in the mass-production dominated automotive field; what evolved was the Toyota Production System, the forerunner to Lean.

Toyota’s philosophy was that first and foremost they needed to know what represented value to their customers. Once this was established they developed systems and processes to deliver it when the customer wanted it, with the quality the customer wanted, in the quantity the customer wanted. This was the start of a new focus for continuous improvement — the customer’s requirements within the process and the basis for the evolution of Lean Manufacturing.

Lean Manufacturing is based on five steps or principles.

1. Customer focus: The first step in a Lean implementation is to identify who your customer is. In manufacturing environments where contact with the external customer is minimal, internal customers need to be identified (i.e., for the maintenance department, it’s the production department). Then the following questions need to be asked:

– What exactly does my customer want?

– When will my customer want it?

– What is the value my customer will measure and how will it be measured?

Once the needs have been determined, measures need to be established to verify that you are meeting them. At this stage customer feedback on your performance is essential, as it will help eliminate any restrictions to customer satisfaction.

2. Value streams: The second step is to look at the process that takes a product from concept to the time the finished goods are shipped and identify where value is being added. The value being looked for is the one the customer will measure and therefore pay for. Anything that is done that the customer does not pay for is considered waste.

This information is visually represented by Value Stream Mapping — taking all of the steps, value added and waste, and drawing out a flow diagram. This allow companies to see where waste occurs or value is added and brings to light opportunities for improvement.

A Future Value Stream Map is then developed, highlighting where improvements can be made and quantifying the effects. Along with the Future Value Stream Map there should be a page documenting how you will achieve these improvements.

There are very often three branches to the map, engineering — design and concept, etc.; manufacturing — the converting of raw materials into finished goods; and administration — the paper trail and indirect services.

3. Process flow: The next step in Lean is to make the process flow. The ultimate goal is to eliminate or reduce all forms of waste (this is called Muda in Lean terminology).

Stops along the process, queues, storage or excessive work in progress are all considered to be waste and need to be removed so that work flows without interruption from one stage of the process to the next. By eliminating these and other functional barriers, lead time to the customer can be dramatically reduced. Issues are dealt with as they happen as the buffer of large inventories has been removed.

4. Pull production: The fourth step in Lean is to manufacture under a Pull system. The Pull concept involves manufacturing components or finished goods in response to a demand or pull from the customer — internal or external. This means that nothing is produced until there is a need for it and production is not based on sales or production forecasting.

There are different techniques for triggering the pull from the customer through the process, one of the most widely use is Kanban — a Japanese word meaning card or communication. This is where a card or bin is returned to the upstream department (supplier) to signal the need for production of that specific component at a predetermined quantity.

5. Perfection: The last step of Lean is the same as any continuous improvement initiative and that is to “seek perfection.” Monitoring of measures and metrics will inevitably lead to the next round of Lean implementation.

In the next article, we will look at how maintenance fits into Lean Manufacturing and how Lean techniques can be specifically used in the maintenance department.

Common Lean terms

Muda: Waste or anything that interrupts the flow of the product through the process.

Kanban: A signal to produce or withdraw a component.

Andon: Lights or boards to allow visual communication in the workplace.

Poka: Yoke — a device or process that prevents errors or defects in the process.

SMED: Single Minute Exchange of Dies — optimum setup and changeover times.

5Ss: A five-step method for creating order and eliminating waste.

TPM: Total productive maintenance — maintenance involving everyone in mastering all maintenance strategies.

Pull: Manufacturing in response to demand from the customer.

Cellular manufacturing: An approach where different types of machines are arranged so that everything necessary to produce an item is available in one location or cell.

Value: A customer-defined benefit or advantage that the customer is prepared to pay for.

Jidoka: Automation through ‘intelligent’ machines.

Takt time: The cycle time or the time required to produce one item at the rate the customer demands it.

About the author

Cliff Williams is a 30-year veteran in the field of maintenance. He has held various positions in industries such as steel, pulp and paper, flexographic printing and packaging. He is currently engineering and maintenance manager with Multipak Ltd., a flexible packaging converter in Mississauga, Ont., with a focus on continuous improvement. He is also a consultant with TMS Total Maintenance Solutions, a Markham, Ont., based company providing custom asset management and reliability strategies.

Williams’ career started in the British Steel industry and he came to Canada in the early 1980s to help commission Stelco’s Lake Erie Works in Nanticoke, Ont. After moving to the paper industry with Atlantic Packaging, he was part of the team that commissioned North America’s first 100% recycled newsprint mill in Whitby, Ont.

Throughout his career, he has been heavily involved in safety and is currently a volunteer with the Industrial Accident Prevention Association. In an effort to help promote asset management qualifications and give something back to the industry, Williams also is an instructor for the Plant Engineering and Maintenance Association of Canada (PEMAC) Maintenance Management Professional Program (MMP) at Durham College in Whitby.

This is the first in a series of columns on Lean Maintenance by Cliff Williams, engineering and maintenance manager at Multipak Ltd., Mississauga, Ont., and a consultant with TMS Total Maintenance Solutions of Markham, Ont. He can be reached at williamsc@sprint.ca.