To Transform Quality, Avoid This Major SPC Mistake
Statistical process control isn’t meant to be a data-collection exercise.
Is your manufacturing plant using statistical process control (SPC) because it’s a “good thing to do?”
It’s a real question. Don’t get us wrong—SPC really is a good thing to do. There’s nothing quite like hearing from a manufacturing quality professional who says, “I can’t believe what we’ve learned and how much we’ve improved! I can’t believe how much money we’ve saved!”
But those results don’t happen in a vacuum. Implementing SPC just because it’s “inherently good” is not enough. It isn’t a compelling business reason for using statistical methods. A solid business rationale for driving quality throughout a company is what results in a successful SPC implementation.
The most successful SPC solutions are those that begin with a strong quality leader saying something like, “I’ve had it with our quality problems. We’re going to turn this plant around.”
And in most cases, the power behind the turnaround comes when everyone—from the shop floor up—is empowered to use the SPC information to take positive, immediate action.
In SPC, Data Collection Is Not the End of the Story
In many organizations, SPC works sort of like this:
- Throughout a shift, an operator periodically takes measurements from some parts. He writes them down on a piece of paper.
- At the end of the shift (or the week), an administrative support person collects the papers from the operators.
- The next day or week, the support person takes the papers, and enters the numbers into some sort of spreadsheet software.
- Control charts are printed out, then placed into company mail, and delivered to a process engineer, who typically exclaims, “Wow, we had something go out of control last week.”
Possibly you have already identified how absurd this “system” is. SPC is meant to be used on the shop floor, in real time, by operators whose tasks include collecting data and responding immediately to out-of-control situations.
The words “immediately” and “in real time” are especially important.
The use of SPC as described above is little more than an expensive and extravagantly ineffective exercise in data collection. An unwanted side effect of this futile exercise is that operators tend to believe that “it’s someone else’s responsibility” to create charts, generate information, and indicate when some sort of action is needed. Nothing could be further from the truth.
Keep SPC on the shop floor—in the hands of operators—and give them the power to react in real time to issues identified by those statistical tools.
When properly used, SPC instantly informs operators of out-of-control situations, allowing an immediate response to the indicated process change (in “real time”). The information needed to control the process is available at the time that the process events occur, and that critical information is made available to the people who are best equipped to manage the process—the operators.
The Power to Change Quality Is Transformational
Time and time again, the experts at InfinityQS have seen what can happen when SPC is used to empower people to take action. A great example came to us from Chris, a manufacturing professional we’ve known for years.
Chris is a plant manager for a large folding-carton manufacturer with plants throughout the world. He was tasked with turning around the plant with the lowest quality levels. Why? Because their biggest customers told them they had a choice: “Improve product quality or lose our contracts.” Millions of dollars were at stake. If the customer canceled, the plant would be shut down, jobs would be lost, and reputations would be ruined.
Chris immediately installed an SPC system throughout the plant and ensured that key personnel were trained to recognize and understand the information they were seeing in real time.
The results were nothing short of stunning. Within a few months, defect levels dropped to just a handful in a million, costs dramatically improved, and productivity rebounded. In less than a year, Chris’s plant surpassed the quality levels of all other plants in the corporation. The customers threatening to pull work were soon giving the plant their highest vendor quality ratings—a rarity in their industry—and awarding them new contracts.
The Lesson of Real-Time SPC: Your Customers Don’t Want Data, They Want Quality
So why do some manufacturers still go through the costly data collection exercise we’ve described above instead of using SPC properly? In many cases, the answer to this question is that the use of SPC is mandated by a customer or some governing body. The customer wants to know that quality checks are happening, so they require that the manufacturer use SPC to create charts showing the checks.
Of course, if there is a week-long delay in creating control charts, problem shipments are likely on the truck to the customer or have arrived in their plant already. Creating charts after the fact is too little, and way too late, to help ensure the quality of a customer’s shipment. Those charts might meet the letter of the agreement, but they miss its intended result.
Chris understood the result that his customers were after—and empowered his teams to achieve the level of quality that was required. Just a couple of months into the SPC implementation at his plant, one of the previously dissatisfied customers sent a letter that said, “We’re not sure what you’re doing, but please keep doing it.”
The “it” was the transformative use of SPC. When asked what his secret was, Chris humbly replied, “We just used SPC in the way it was meant to be used. SPC was the primary reason for the incredible turnaround of this plant.”
That plant went from the company’s worst to first in less than a year—all because of a compelling, motivating rationale for using SPC in the first place. Since then, Chris has transformed the quality levels in two more plants in his company by using SPC with vigor, motivation, and a business reason for doing so.
To learn more about obtaining actionable information from the data your operators are already collecting, visit our website and check out our Definitive Guide to SPC Charts and our learning centers, SPC 101 and New SPC Tools for a New Era of Quality.