What, exactly is SPC? It’s a question that will generate different answers from nearly everyone who is asked. Quality professionals who use statistical analysis tell stories of transformative improvements and expensive failures. But there’s no doubt that SPC is not only a foundational part of manufacturing quality and process control, it’s also a vital part of the future of industry.

The answer we’ll explore here is a strategic one: SPC is about improving quality, reducing costs, and enhancing a company’s competitive position.

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SPC: It’s Not Just About Control Charts

For me, as a Six Sigma Black Belt and quality consultant, SPC is a lot of things. It’s about:

  • Extracting meaningful, actionable information from data.
  • Operators controlling their processes on the shop floor.
  • Six Sigma teams delving into an important project.

Managers, maintenance supervisors, operations directors, engineers, and business leaders focusing on quality, reducing costs, and improving their company’s bottom line.

SPC is a simple yet powerful means of supporting all of these actions and uncovering valuable information for all levels of an organization.

SPC chart

SPC is much more than shop-floor data collection. And it is more than the use of control charts. Yes, control charts are great SPC tools that can be used by operators on the shop floor, but they represent just a fraction of the many tools that can generate meaningful, actionable information from an SPC system.

In addition to being used for process control, SPC is also about repurposing shop floor quality data for use by quality professionals, managers, Six Sigma specialists and engineers who need insight into the “big picture” of quality.

These professionals don’t necessarily need to view control charts. What they need is summary information that can be used to understand quality levels across multiple product codes, lines, and plants. They need greater visibility into where they can make the greatest improvements in their business in the shortest amount of time. And it’s possible—even easy—to do it. They just need the right data aggregation and analysis tools, and a commitment to review those data regularly.

The most transformative improvements in quality, productivity, and cost reduction I have witnessed have all been the result of consistently aggregating and summarizing shop floor data. That’s right: The same data that have already been collected and analyzed on the shop floor can provide insights into where big improvements can be made.

The Big Payoff

In my estimation, about 15% of the benefit of SPC is out on the shop floor. It’s process control, tweaking, troubleshooting, prevention of problems, and efficiency improvements—the good work that operators do when they have access to control charts.

But that means the remaining 85% or so of the benefit of SPC is in the data that nobody is looking at—the data that haven’t indicated the presence of problems. My experience has been that unless data indicate a quality problem, it is ignored. Data that are within specification limits, for example, get saved to the database and rarely (if ever) viewed again for improvement purposes.

The result is that too much time is spent dealing with quality problems rather than determining how they can be prevented. When you spend your energy, focus, and resources on constantly fighting fires that occur every day on the shop floor, it’s understandable that quality professionals don’t have time to look at anything else.

Constantly putting out the quality fires is exhausting. It’s necessary and valuable, but it tends to take time away from big-picture cost containment and quality improvement activities that can have a positive impact on business performance.

SPC ROI is in Data Aggregation

To generate big returns on your SPC investment, you need to focus on the big picture of what’s going on across your organization. Instead of focusing on quality problems, you need to look at data that represent quality information across multiple production lines, shifts, plants—across the entire enterprise.

And the way to get the big picture view of your organization is with data aggregation—rolling up data across your manufacturing enterprise and uncovering where the greatest opportunities exist for reducing waste, reducing costs, and improving quality. This is how you get a huge return on your SPC investment.

You don’t get that big picture view by looking at data from machine 4, shift 1, on the shop floor in plant 2. You get that big picture view by looking at data from all your machines, all your shifts, and all your plants. If companies want to know how best to improve the organization’s overall quality and manufacturing performance, they need to expand their view across the organization.

Resuscitate Your Manufacturing Data

Quality professionals, managers, Six Sigma folks, and the like need to resuscitate shop floor quality data—give them a second life. Why? Because the second life of your data contains the gold. It’s what will make your SPC investment worthwhile. Allow me to explain.

Typically, quality data are viewed first by an operator on the shop floor. These first-life data are what operators use to control their processes. The information generated by control charts empowers operators to fix issues quickly and keep their machines running smoothly. But the useful life of a plot point is measured in seconds.

Once consumed on the shop floor, those data are typically archived and forgotten. But they shouldn’t be. Those data can be re-used. Summarizing the same shop floor data at a higher level allows them a second opportunity to provide insight into how to improve—but in a bigger way. That’s why the second life of data is so important.

spc data

When the same data that have been used in production for process control have been aggregated and summarized, you enable engineers and quality professionals to dig deep and find the rhythms and patterns present in multiple manufacturing processes. Analyzing data in their second life is where huge improvements and cost savings are identified.

spc chart

The Big Picture is Key

Your operators keep an eagle eye on process data, spotting trends and plot points that indicate an issue—and thereby keep things up and running. Your quality pros and Six Sigma teams repurpose shop floor data and give them a second life by looking for big-picture opportunities for improvement. They can identify where they can fix things, transforming first-life data into manufacturing intelligence.

It’s not hard. You just need systems that will support shop floor, enterprise-wide data collection and a means of aggregating those data and making them easily consumable and understandable by managers, engineers, and quality professionals.

Modernize SPC Solutions

We have all heard that organizations “don’t know what they don’t know.” That’s because, historically, the lack of technology prevented them from viewing the big picture of quality. Or, because generating enterprise-wide quality reports was impossible. But that’s no longer the case. Technology has caught up.

We have SPC software solutions that empower companies to do exactly what we’re talking about here. These inexpensive technologies currently allow organizations to easily (and regularly) review aggregated data, enabling them to uncover:

  • Where their highest defect levels occur across all plants
  • Which production lines require the most attention
  • How they can positively impact costs and quality across the company
  • Which quality costs are primarily affecting their bottom line
  • Where they can improve cross-plant efficiencies the most
  • How to make the greatest impact on quality performance across the company in the shortest amount of time

Using SPC on the shop floor is great. It’s necessary for controlling processes and for gathering quality data that can be summarized later for making big improvements.

However, resuscitating and repurposing shop floor data to gain manufacturing intelligence is the key to big returns. It’s how organizations realize 85% of the benefit of an SPC system. Leveraging the second life of data will enable you to use SPC holistically and extract the most from your system. It’s the key to saving money, cutting down on scrap and waste, and transforming your organization’s performance.

Take a closer look at SPC on our website.