In his still-insightful 1999 book, Fast Track to Waste-Free Manufacturing: Straight Talk from a Plant Manager, John W. Davis discusses how to improve a manufacturing operation by a simple and relentless focus on waste. The methodology he describes is really applicable to improving any process in your business.
A change to waste-free manufacturing can take 12–18 months and must be daily led by the plant manager. Waste-free manufacturing is a never-ending process that simply will not allow business as usual. The goals: 1) Reduce setup and changeover to a point where it has no bearing on the level of standard inventory carried in an operation; 2) Maintain equipment at a level where breakdowns simply do not occur; 3) Suppliers should always delivery on time without exception; 4) Use proper production techniques that avoid producing bad parts, scrap and rework; and, 5) Strive to put a process in place that clearly reveals problems and then fully resolves them—once and for all—rather than striving to cover for problems.
There are five mental barriers to change:
- Justification – "It’s good enough."
- Not invented here.
- Done that before.
- Don’t rock my boat.
- It’s not my job.
And four key drivers for waste-free manufacturing:
- Workplace organization (straighten, sweep, sanitize, sustain, sort).
- Uninterrupted flow.
- Error-free processing.
- Insignificant changeover.
- Workplace organization.
Anything in the selected area not immediately needed for production is removed. There has to be a defined place for everything and everything has to be in its place. Audit all materials and tools to make sure they are necessary. Simplify the designs of the products to use common parts. In most conventional manufacturing operations, at least 25 percent of all the equipment, stock, tools and fixtures, equipment, tables, benches, storage cabinets and other things that take up valuable floor space simply is not needed.
Uninterrupted Flow. List every part or subassembly that requires a stop and brainstorm all potential options that would eliminate any of the stops identified. Equipment may need to move several times in pursuit of uninterrupted flow.
Error-free Processing. At the outset, you must perform appropriate root cause analysis (use the 5 why analysis). If most manufacturing operations could completely eliminate all their setup and changeover, they typically could reduce their assigned manufacturing costs by up to 20 percent or more. A production line that does not shut down is either a perfect line or a line with big problems where problems are not surfacing.
Insignificant Changeover. Reduce time spent on setup and changeover. Mistake- proofing, or poka yoke, looks at methods and devices that eliminate common mistakes made in the production of parts, components, sub-assemblies, or finished units. Focus on the concept of SMED (Single Minute Exchange of Die). Relentlessly search for ways to reduce changeover and set-up time and effort.
Workplace Organization. Conventional wisdom considers it a waste to have a group of employees standing around with nothing to do. In fact, it is far more wasteful to have these employees producing parts and components that are not immediately needed. Also, managers should strive to reduce inventory. Evaluate suppliers as certified to deliver to point of use. Look at inventory in days divided by lead time of items. The goal should be to get inventory down to hours rather than to days, weeks or months.
Other Fundamentals. Measure the distance parts, components, and assemblies travel throughout the factory. Employees will view this as a substantial waste and apply themselves in the effort to attain the ultimate goal of zero parts travel.
You should view your workers on the floor as the most valuable of all employees in the factory. Where possible, locate the salaried workforce on or very near the shop floor. After initial wins, management needs to express deliberate impatience to move the factory along at an even more rapid pace.
Final Questions. Does the plant or factory look world class? Is it superbly clean? Is there a place for everything and is everything in its proper place? Is the process simple and intuitive? Does the process flow smoothly without interruption?