Lean Manufacturing

Introduction

            Lean manufacturing has been defined as "a systematic approach to identifying and eliminating waste (non-value-added activities) through continuous improvement by flowing the product at the pull of the customer in pursuit of perfection." The notion of lean manufacturing is not new and has been identified in many different ways and even with many different names. It has been called: flow manufacturing, the Toyota Production System, one-piece flow, just-in-time production, and demand flow technology.

            Lean Manufacturing is simply the elimination of waste in the manufacturing process. Waste can be in the form of material, time, idle equipment, or inventory.  Lean Manufacturing helps to improve material handling, inventory, quality, scheduling, personnel and customer satisfaction.  A lean manufacturing process is one that continuously strives to eliminate waste, thereby increasing the percentage of time devoted to value-adding activities. The more value you can add in your overall process, the more effective your operation will be. In lean, the customer drives the process. Production is to deliver to the customer exactly what they need, exactly when they need it, in the exact quantity, with the highest quality at the lowest possible cost.

Lean Manufacturing Procedures

            The main objectives of Lean Manufacturing are to challenge all processes to simplify, streamline, synchronize, and create cost savings.  There are many techniques that will help you to achieve this in your organization.  For one, creating manufacturing cells can eliminate the wastes of material handling, excessive motion, work-in-process inventory and more.  Employing Total Productive Maintenance (TPM) can eliminate the wastes of unplanned downtime, waiting, defective parts and others.  Even changing the layout of the plant will often eliminate the wastes of transportation, over-production, unnecessary processing and other wastes.

            These are all excellent techniques, but we may not be applying them to the right areas of the business unless we have looked at our company's value stream - all of the activities that take place from order acceptance to the customer's receipt of the product.  To begin the quest for lean manufacturing, we should think about a technique called value stream mapping.

            Value stream mapping is a visual technique for describing how a business currently operates, and could operate.  A value stream map displays the flow of information and the flow of materials.  Information flow is quite often overlooked; however, without an effective information flow, there can be no material flow.  Generating a value stream map will help problem areas to stand out clearly.  You will see places where inventory is building up, both before and after production processes.  You will see where long machine setup times and unplanned downtime are an impediment to flow.  You will see evidence of unbalanced labor, or machine time, between processes creating delays.  You will easily identify the place, or places, in the value stream where you will need to start your waste elimination efforts.  Taiichi Ohno, former VP of production at Toyota Motors, and the co-creator with Dr. Shigeo Shingo of lean manufacturing explains this idea through the following analogy:

“This river is inventory, and it flows through our factories covering rocks-these rocks are the manufacturing wastes. The wastes are problems hidden by the inventory.  Our job is to remove those wastes.”

            Once you have completed the value stream map you will be able to visualize how things could operate. This vision will be the basis of your future value stream map. In this value stream map, you will have the ability to eliminate processes that add no value and then streamline those that do. You will emphasize areas where your suppliers can provide better services. You will eliminate redundant and unnecessary information flows. All of these changes will in turn directly affect your end customer.

Results of Implementation

            The key questions to ask about your Lean Manufacturing implementation are:

·         Will the process have fewer tasks?

·         Will the process be faster?

·         Will the process be more flexible?

·         Will there be fewer non-value-adding activities and tasks?

·         Will production floor inventories be reduced?

            Keep in mind that lean manufacturing is a systems approach.  Each phase builds on the previous one.  All processes that deliver value and all processes that support the delivery of value must be integrated.  Leadership, technical components, and value-adding activity must be balanced, blended, and synchronized.  Also remember that total cost will be your ultimate performance metric.

Lean Thinking at Boeing

            Stanley Kandebo wrote an article in Aviation Week & Space Technology about the success of Boeing’s new X-32 jet due to lean thinking.  The underlying technology making these improvements possible is the company's state-of-the-art Catia three-dimensional solid-modeling techniques. This technology allows Boeing to electronically assemble the whole aircraft checking for fit, obstructions and clearances before cutting the first piece.  And, because the entire aircraft exists as a 3D database, manufacturing engineers also can use proprietary software to conduct virtual simulations that help determine the best assembly routines and sequences for assembling an aircraft. 

            The company’s achievements with the design and fabrication of this new fighter prove that when properly applied lean techniques are introduced costs, complexity, and errors can be dramatically reduced.  According to Boeing officials, the X-32 aircraft cost 75% less to build than original company estimates.  And corresponding with these cost reduction achievements, the company was able to drive down the X-32's manufacturing defect rate. There were about 80% fewer defects in the first X-32 than in the equivalent build on a prior model. 

Quality Resources

            If you wish to learn more about Lean Manufacturing, then the following books will be of great assistance:

Feld, William M.  Lean Manufacturing:  Tools, Techniques, and How to Use Them.

Henderson, Bruce A.  Lean Transformation:  How to Change Your Business into a Lean     Enterprise.

Liker, Jeffrey K.  Becoming Lean:  Inside Stories of U.S. Manufacturers.

Womack, Jim.  Lean Thinking.