July 9, 2013
The Two Lives of a Control Chart
There is no disputing the fact that control charts have become an integral part of the manufacturing quality control process—namely due to the fact that the charts can instantaneously analyze data from the shop floor, review the statistical patterns and determine if process variability falls within an acceptable range. But did you ever consider the fact that there are two lives to a control chart? Let’s dive deeper.
The First Life: Do Something or Do Nothing
One of the chief benefits afforded by a control chart is its ability to present real-time data to manufacturers and engineers. Based on the feedback, these teams can instantly detect manufacturing problems and rectify the situation before the plant incurs additional costs and scrap. During the first life of a control chart, the operator is tasked with either “doing something” or “doing nothing,” meaning he/she will either make adjustments or let a process continue as is. The result? A reduced margin of error and an immediate solution.
The Second Life: Creating a Better Tomorrow
While it is incredibly important to receive data in real time so that you can act swiftly, it is also equally as important to compile data to analyze at a later date. Control charts also allow operators to collect a substantial amount of data and store it in a database so engineers can run reports and identify trends over set periods of time.
“During this lifecycle, process engineers can look at the data to determine whether they can set the job up the same way they did last week,” Steve Wise, vice president of Statistical Methods for InfinityQS, says. “Engineers use this data to make things better for tomorrow.”
Are There More Lives?
In theory, the shelf life of a control chart is long, especially since so many key stakeholders—from manufacturers to operators to engineers to the customers who actually purchase the parts—have a vested interest in reading the data. With so many groups wanting a holistic view of the plant floor or a snapshot of data, control charts have become a vital part of the manufacturing quality control process.