subject: Lean Manufacturing Techniques for Identifying Waste [print this page] Lean Manufacturing Techniques for Identifying Waste
Much of the time, it's the most obvious things we overlook. It's no different with implementinglean manufacturing, where elimination of waste is paramount, in the pharmaceutical industry.It's just that some forms of waste are more detrimental while being so obvious they're hidden.That means the tools used to identify and analyze these wastes are definitely worth looking at.Take, for instance, these two forms of waste: over-production and waiting.
Over-production and Schedule Adherence
Over-production seems on the face of it to be a counter-intuitive notion. We've all beenconditioned to think that in manufacturing producing as much of a product as possible is agood thing. But lean manufacturing tells us otherwise because customer demand (whetherthat customer is the next downstream segment in the production process or the end user ofthe final, packaged product) should "pull" the product from one upstream place to the nextdownstream. So production isolated from customer demand is meaningless.
That's why a metric coupled with the right management philosophy designed to determinewhether production is aligned with customer demand is so important. Deploying the schedule-adherence metric is a way to accomplish both objectives on the way to implementing leanmanufacturing techniques.
Here's the formula: schedule adherence = (total plan sum of deviations) / total plan. Fullschedule adherence is arrived at when the planned quantity of the product has been producedfor each SKU. This is a tool that assists in matching, as well as helping managers to keep in mindthe need for that matching, production with actual product demand. The goal is to produceonly what is needed in the amount and at the exact time needed.
Waiting, Value-Stream Mapping, and CT/TT Charts
Unnecessary waiting, because it is an indirect form of waste, is also often overlooked. Waitingis the expression of certain imbalances between and among processes, as well as a result of variability in the chain as a whole. That variability can be either inherent (owing to built-in limitations on resource capabilities and/or resource constraints) or adventitiously imposed (which is the case with large batch sizes and the related processes). The tools used to locate,analyze, and eliminate this form of waste are value-stream mapping and cycle-time/takt-time
(CT/TT) charts. Here are some of the broad steps involved:
Cycle time for each step in production is measured, and for steps involving equipment,mean-time-to-failure (MMTR) and mean-time-to-repair (MTTR) data are recorded.
Lead times are measured and recorded in quality/inspection areas.
Each of the items below is noted for every process in the value stream:
a. Number of resources
b. Set-up frequency and time
c. Uptime
d. Lead time
e. Cycle time
f. Inventory levels
g. Scrap level
The takt time is then calculated by dividing total time available by actual demand (often expressed in number of units).
Finally, the difference between processing time and lead time (including queuing time) is noted.
With all this data mapped and charted, companies are able to determine where wastefulwaiting occurs and how it can be eliminated.
Lean manufacturing consultants with the right tools can make your implementation of Lean techniques a waste-reducing, profit-improving success.
