Lean thinking identifies that there are "Seven Wastes" of production. The beauty of Lean is that its methodologies are transferrable from the manufacturing environment to other areas such as administration, project management and design. This article explores the application of the "Seven Wastes" to Design and comes from the Society of Manufacturing Engineer's newsletter "Lean Directions". For more information visit www.sme.org/leandirections.

Lean thinking focuses on identifying and eliminating waste throughout the value stream. All of the principles of lean (customer focus, value, flow, and pull) are part of the relentless pursuit of waste elimination. The waste that we are able to see on the manufacturing floor and in our processes include: searching, moving, stacking, training, documenting, inventorying, handling, scrapping, re-machining, machining some more, adjusting, inspecting, etc.

Many times these wastes are a result of "bad" designs. Do engineers purposely develop "bad" designs? Of course not. But for the most part, product design is not tightly linked to the downstream internal customer (the manufacturing process). The cause and effect are separated by time. It is the rare and fortunate engineer who can create a product design, then see it immediately implemented into production so that he/she can gain feedback and apply it to the next design effort. For the rest of us engineers, the feedback comes months, even years later.

For example, designs that can be put together wrong, or require complex manufacturing processes to ensure that the assembly process is tightly controlled, are bad designs. Such designs mean that work instructions, training programs and verification points must ensure that the product is manufactured "right the first time."

Bart Huthwaite from the Institute for Lean Design characterizes wastes resulting from "bad" design as the evil "ings" (training, inspecting, verifying). None of the "ings" would be required if the design could be assembled only one way, the correct way, the first time.

The Seven Wastes of Design

Design engineers are not without tools or without interest in making better designs. Companies have spent millions on developing reference materials such as produceability manuals, checklists, design guides and technology tools. Unfortunately, these tools tend to influence the design during the final stages of development rather than at the earlier concept stages.

Up front in the process, significant influence to the design can be realized through integrated product team concepts if they are applied early and broadly enough. Lessons learned are also reviewed but are more "post mortem". But these still are attempts to bridge the gap between design and truly good design.

To design-in lean principles without checklists and manuals, designers and engineers must make lean thinking second nature. The fundamental understanding of why we need to bridge this gap requires the ability to "see" the seven wastes of production on the factory floor for what they are -- a direct result of the product design. By learning to see these wastes, we will be able to recognize the design behaviors and tactics that result in them.

The concept of the seven wastes was first codified nearly 50 years ago by Toyota executive, Taiichi Ohno. Ohno's contribution was to help people recognize that waste is what drives up cost and that the seven wastes are inherent in all processes. The seven wastes and how they relate to product design are described as follows.

Waste #1: Overproduction

What we "see" on the shop floor are parts stacking up, with temporary stocking locations, and additional handling and warehousing, which are additional symptoms of this waste. These symptoms are also evident at supplier facilities. Overproduction is the waste of producing a product, service, or information before the customer needs it, or producing more than is needed.

The design of the product can contribute to waste of overproduction as follows:

Waste #2: Transportation

Transportation is the movement of product, materials or information that does not add value. On the shop floor, we can see product moving in and out of storage and from one work area to the next. Going outside the shop floor, we can see product traveling distances to the point of use.

Features and functions of the product design can contribute to transportation waste as follows: in the design, not considering how large, heavy or cumbersome items will be handled in production; designs with multiple parts that could have been simplified; and specifying parts that must be purchased from suppliers that are geographically far from the place of

• expanding the scope of the requirements (adding features that do not tie to customer requirements or marketing needs);
• including too many options or details on how to make or test the items, thereby dictating manufacturing processes; and
• designs that require batch production, such as those using highly specialized metals, specialized compounds or chemicals made by a sole source--this also includes designs to be manufactured using high-cost setups or low-yield processes.

Waste #3: Motion

Movement that doesn't add value constitutes the waste of motion. Searching, reaching, walking, sorting and bending are the symptoms. A great deal can be done in the manufacturing flow to eliminate or minimize this waste, but once again, a great deal could have been done by design. Unnecessary movement is also the cause of many injuries in manufacturing due to repetitive motion and the unnatural positions required.

The design of the product can contribute to motion waste in production as follows: Designs that are not "out in the open" for easy use, maintenance and manufacture/ assembly will require more motion.

• Designs that are not easily oriented for use, maintenance and manufacturing and don't make effective use of symmetry will require more motion in production.
• Lifting cumbersome or heavy parts requires motion when it is necessary to add and then remove fixtures, and when multiple moves are needed to position the item.

Waste #4: Waiting

Idle time in manufacturing is created when material, information, people or equipment is not ready. We wait for parts and prints, inspection and machines. The product design can cause waiting in the downstream production processes as follows: Testing and verification are to be performed at the wrong level for process feedback and correction. If it can't be verified as a system until the next higher level of assembly, the operator waits to know if the job was done correctly. Production startup delays due to incomplete or inaccurate design information. Design programs strive for zero risk and are therefore never quite done to the required schedules. When designs do not anticipate improved technology insertion (platform/product family concepts) production planning will be delayed.

Waste #5: Overprocessing

Effort that adds no value (from the customer's viewpoint) is considered overprocessing. If a flatness of 0.001 inch (0.03 mm) is required, you don't want to pay for a precision grinder to grind to a flatness of 0.0001 inch (0.003 mm). Analyzing, testing, inspecting and validating are symptoms of this waste in manufacturing, as are multiple machining or assembly steps. Features and functions specified in the product's design can generate overprocessing waste as follows: Designs may not consider production process capabilities, creating waste when attempting to meet an over-specified need for precision. Specification and source control required by a design add no value. They are limiting. Complex designs require complex manufacturing processes.

Waste #6: Inventory

More materials or information than is needed to serve the customer right now is considered the waste of inventory. Each part in a design must be ordered, transported, and stored multiple times until it is finally assembled into the final product. How much does a part cost? A lot more than the material and labor costs to manufacture it! The material handling and purchasing costs can eclipse it! Consider the fact that each part must be ordered, purchased, transported, stored and pulled to the line for final assembly. Additional costs include data processing, manufacturing engineering, quality assurance, inventory control, stocking and shipping. Warehouse space also adds cost to a part. A study conducted by Coopers & Lybrand and Worcester Polytechnic Institute ("Economic Justification for Part Number Reduction During Product Design") in 1991 estimated that the yearly cost per part number in one global case study was $9,437 each. And this only represented part of the total costs.

Waste #7: Defects

Defects are the most obvious waste in production. Reworking, analyzing, problem solving (or fire fighting), and scrapping are readily seen. Any work that contains errors, mistakes or lacks something necessary is a defect.

The design of the product can have a direct relationship to this waste and may provide the greatest opportunity to eliminate it. If the part (by design) can be assembled wrong or used incorrectly, defects - waste -- will occur. If design data is missing, unclear or incorrect, defects will occur. In addition, if a feature requires precision or tighter tolerances for a particular manufacturing process, the yield will be lower and defects will be found.

Another type of defect is a design that doesn't meet the customer requirements. In the "old days," a design might have gone through an iterative process to "fix" it. It would be run in production, then the design modified and perfected based on feedback from the customer. Today, "first unit correct" is needed to support rapid time-to-market requirements and the need to continuously remain competitive through technology updates.

Although much can be done in the manufacturing process to identify and eliminate wastes, there is much that cannot be done because these wastes are symptoms of the larger issue of "bad" product design.

About the Authors:

Alice Mary Conner is Manager, Process Solutions at United Defense LP, Ground Systems Division, located in York, PA. She has held management positions within procurement support engineering, quality engineering and production support engineering. Her experiences include working within research & development as well as manufacturing. Currently, her role is to help lead and facilitate lean thinking within the office processes.

Jon Miller is a leading facilitator and teacher of process improvement techniques. Fluent in Japanese and English, he began his 10 years of study with the Japanese masters of Kaizen before the study and implementation of the Toyota Production System came to be called lean manufacturing. Since founding Gemba Research in 1998, he has been instrumental in helping over 80 companies achieve breakthrough results. He has trained over 1,500 people in lean thinking and Kaizen tools. For more information, find Gemba Research on the web.

Kathy Mullen works for United Defense LP, Ground Systems Division, located in Santa Clara, CA. She has worked in production engineering and design and development. She is the engineering design quality lead for lean applications in engineering.