8. What Are the Wastes to Eliminate?

The phrase lean manufacturing in its simplest sense is self-explanatory. (That may be part of the problem—everyone has decided to explain it to him or herself.)

A lean operation is one that has trimmed away its fat, which in most circles is called waste. Lean gurus attempt to pinpoint the different types of waste that one finds in a manufacturing facility so that they may eliminate them, or trim them away. Some cite seven types of waste, some believe there are eight. Following is a look at seven wastes that you might look to eliminate in your facility to become a leaner operation.

Overproduction—According to Fred Sanders, Intermet Corp., Fort Worth, Texas, overproduction is the most critical of the wastes lean manufacturing tries to eliminate. Manufacturers make extra product as a cushion, but in reality the excess merely hides process shortcomings.

Motion—Every movement your floor workers make takes time and energy. Creating cellular workspaces with repeatable activity schedules allows employees to economize those motions.

Correction—Errors upstream create more work downstream in the form of necessary corrections. Fixing these problems before they start is more efficient than fixing them after the fact. For example, your molding room might be able to eliminate a finishing step by doing its job better.

Waiting—Employee waiting, be it due to a down machine or another process in the facility lagging behind, constitutes a waste that must be eliminated. One way to eliminate waiting is to cross-train employees. If one worker is burying someone downstream from him/her, adequate cross-training allows them to step away from their work station and assist in the other activity. Proper preventive maintenance can reduce waiting due to down equipment.

Inventory—Inventory can be hiding throughout your processes, not just in the shipping department. Excess cores and castings in process constitute inventory, as well, and should be minimized in order to lean operations.

Transportation—Like employee motion, taking parts from point A to point B requires additional time and effort, which leads to increased costs and more works-in-process. Cellular and linear plant layout can minimize wasted transportation.

Extra Processing—Like correction, extra processing can be eliminated upstream from its actual occurrence. Sanders asked why permanent mold facilities assume they have to put their castings on a trim press to remove the flash. “Why not just eliminate the flash during production?” he asked.
Grinding beyond that which is required by the customer requirements is also a waste of extra processing.  This waste is often related to the poor job of visual inspection in determining if a casting is acceptable.  MC