As a manufacturer, plant manager, controller, or machine operator, you've undoubtedly encountered the concept of lean production. Lean this, lean that-lectures, brochures, talks, forums about how lean approaches to shop management can control and even reduce costs. In today's era of ever tightening margins, where even the slightest gains in efficiency can translate into considerable improvements to the bottom-line, lean manufacturing has become not only a way of life but also a philosophy in and of itself. Imagine the repetitive production line where pennies saved per part or assembly sometimes translate into thousands of dollars per hour put back into the plus side of the ledger.

In prior postings, we've listed benefits of leaning, as well as some of the broad waste concepts associated with lean philosophy in manufacturing. In this article, we will nuance some of items in those prior lists and offer more specifics as to the meaning of "waste" in production. With an eye toward operating within a lean structure, identifying potential areas of waste and continuously improving production through their elimination is what efficient manufacturing is all about:

Over-Production - In short, selling products at or below cost of production is not going to be very profitable. As well, warehousing products for a customer before they are actually ready to take delivery wastes both space and capital.

Inventory - Why have materials, parts, and other inventory just sitting around, waiting to be used at some unknown point in the future? Zeroing-out inventory is a waste-elimination concept designed to free up more capital while also making inventory more manageable.

Motion - The relationship between production time and operator motion has been studied over and over again. Findings show that unnecessary or awkward operator motions put stress on the body and cause waste in shop floor time management. To gain more productivity out of what is invariably a limited resource (i.e., time) is always beneficial. Another positive outcome to the elimination of wasted motion might also be found in the reduction of injuries and workman's compensation claims.

Conveyance - This is usually defined as the unnecessary movement of part(s) during the production process, and it considers the potential of damage that can come to material that is moved about without need. In high precision production, such damage can even be the basis of wasteful (and costly) rework.

Correction - Whether damaged in conveyance or the result of any other scrapping malady in production, having to re-work parts is a fairly frequent source of waste in manufacturing. Taking an excessive amount of time for sorting and inspecting parts is also wasteful and can be reduced through error proofing (i.e., designing processes so products can only be produced one way, which is the correct way, every time).

Processing - Like never before, clear communication between manufacturer and customer is absolutely necessary in order to work most efficiently. Of course, questions about such things as engineering and production material requirements must be answered before production begins. However, if a customer is continually changing processes or other requirements, the additional steps might be added to a job that does nothing more than simply add additional costs to the product.

Waiting - When an operator is on the clock but not on a job, this is a direct-cost waste that goes straight to the bottom-line. The occasionally idle machine is an expected aspect of the economic cycle; an idle operator (or one taking an hour or so to look for a part or tool) is usually the result of bad scheduling, inefficient shop floor control and design, or both.