Monday, October 6, 2008

SMED and TPM

Standardization is not just for tooling or the element that is being exchanged. It applies to what is not being exchanged, the machine or permanent element. Adjustment becomes necessary if the exchanged element, or the permanent element, or both, have variation in performance. It is especially difficult to get right if both are varying from one run to the next.

Standardizing the tooling or exchanged element will not eliminate adjustment if the permanent element, a machine, system, or program, is not stable and standardized. There is thus a link between SMED and TPM, between setup reduction and maintenance. Wear, vibration, and other kinds of drift from the design condition all create problems that must be dealt with during setup. This kind of instability is particularly troublesome, because they cause the internal aspect of the changeover to take more time. If the condition is not known, or not dealt with during scheduled maintenance, then it must be dealt with, whether directly, or provisionally, during changeover. The second approach is, unfortunately, more common, because of the rush to get back up and running. Thus, the problem is faced again and again, with no chance for standardizing the internal setup procedure.

Careful observation is required to disentangle the sources of variation. Preventive maintenance and equipment improvement are necessary to eliminate variation in the permanent element of the production system.

No comments: