Widely used by the automotive, aerospace and other mission-critical industries, statistical process control (SPC) software offers its users a simple way to monitor and analyze quality data from their manufacturing processes and machines using sophisticated statistical tools. The software breaks down the results into user-friendly charts and graphs that enable managers and operators to make real-time decisions during production that prevent the manufacture of bad parts that must be scrapped or repaired. That means SPC software can save time and money.
Increasingly, manufacturers are also turning to SPC software for more integration with other enterprise management software, improved data output, such as text reports, and new wireless capabilities for data collection and gage tracking.
“Automotive and aerospace will settle for nothing less than perfect parts,” said Robert Fruit, ASQ-certified Six Sigma Black Belt, CQE, Senior System Engineer, CT-Lab Chicago, Mitutoyo America Corp. (Aurora, IL), developer of the MeasurLink metrology software that includes SPC. “When they pick up a part to put in an assembly, the part must fit and work as expected or the automotive or aerospace final product is not saleable. SPC information for their suppliers is their guarantee that the supplier parts are guaranteed to work. As Deming and Juran both emphasized, you cannot test your way to perfect parts, your system must be controlled to make perfect parts. SPC is a key measuring tool to make sure your process makes perfect parts.”
Today’s SPC software is more geared toward the shop floor, offering operators more immediate, real-time data for maximum impact on factory-floor operations. “Traditional SPC was handwritten data sent to a QC Lab where someone created, by hand, Control Charts and Capability Reports [Cp, Cpk],” said Fruit. “This often got management information about their manufacturing process after product had already left. The data was typically used to make sure that their manufacturing process was repeatable at its current level. The work was not difficult and when programs like Excel came along, people took the handwritten records from the floor and typed them into Excel macros. This was a baby step above the ‘by hand’ methods it replaced, but SPC information was not getting to management much faster than with the by-hand methods.”
Modern SPC programs along with affordable computers are capturing the data directly from the gage with no handwritten records, providing instant charting that the operator on the floor can respond to, Fruit said. “This gives the operator more responsibility in controlling a process and the information that operator needs to know when to respond,” he noted. “When operators based controlling a process by reading a measurement and, if it felt appropriate, adjusting the process, it would lead operators to over-control a process, reducing its capabilities. With on-screen mapping, the operator can be taught to wait for multiple measurements, moving in the same direction before responding, and thereby avoid over-correction.
“The big trend in SPC is affordable computers at an operator station, collecting data directly from gages, graphing the results in real time and having operators trained so they know what actions to take at the appropriate times,” Fruit said.
In addition to shop-floor systems running SPC, users increasingly are looking for mobile access and cloud-based SPC implementations that offer instant, around-the-clock access to key manufacturing process data metrics. “Mobile is coming into play. We get a lot of requests for it. With smartphones and iPads becoming so prevalent, it’s reenergizing [SPC usage],” said Evan Miller, president and CEO of Hertzler Systems Inc. (Goshen, IN), developer of GainSeeker SPC software.
The MTConnect data standard also is helping manufacturers with easier data interchange capabilities, Miller said. “I think it is the universality of it [MTConnect],” he said. “OPC has been around a long time, and MTConnect is the newest source for process data. People are really interested in real-time data. It’s what enables them to drive performance.”
Connecting via portable devices, often to cloud-based SPC or to other manufacturing software, has become virtually mandatory for many users. “As private citizens, we’re more accustomed to using all this cool data on our cell phones,” said Steve Wise, vice president, statistical methods, InfinityQS International (Fairfax, VA). “I think that the expectations for manufacturing systems and quality/SPC systems are there as well.”
Being able to exchange shop-floor data in real time, tracking key metrics like Overall Equipment Effectiveness (OEE), is critical to manufacturers’ success with SPC implementations. With the downsizing of the last recession, many shops have less experienced quality people on board, leading to a greater need for SPC. “I think we lost some core competencies in the recession in 2009,” said Hertzler’s Miller. “There were a lot of things people were doing that got lost, and there’s a lot of rebuilding going on.”
A recent study by LNS Research showed that manufacturers using real-time SPC data have a 7% higher OEE level than those that do not, Miller added. “It’s well-documented that real-time SPC is going to drive real benefits into your system,” he said. “In terms of productivity and quality, there’s no doubt that SPC has a major impact on your organization. There’s a huge financial benefit to doing it on the floor—it’s absolutely critical.”
In January, Hertzler released its GainSeeker Suite 8.3 SPC software, which added new OEE charts, new scrap costing features designed to help users analyze and cut down on scrap, and a new Inspection Editor to help customers create inspection processes that can run on a standard computer or a mobile device like the iPad, which has a downloadable GainSeeker Collect app.
When considering an SPC solution, customers also should look at the rich benefits from a “pure-play” SPC system (offering only SPC) like Hertzler’s, Miller added, that deploy faster with much faster payback than an Enterprise Quality Management System (EQMS). “We bring some core competencies that are really going to be difficult to mimic, including our database and computer savvy,” he said. “It’s pretty easy to create a control chart. It’s quite another thing to link that to all your other quality data.”
With manufacturers requiring fast, easy retrieval of SPC data, the new DataPage+ SPC software from Hexagon Metrology (North Kingstown, RI) collects and monitors that data in real time for quick analysis of shop-floor processes. The DataPage+ SPC application and a companion product, the DataView CAD add-in, is an SPC toolset for metrology data with real-time monitoring, graphical reporting, and automatic report delivery. The latest release delivers upgrades for efficiency and ease-of-use, as well as FDA 21 CFR Part 11 compliance. The SPC software includes enhanced custom reporting features enabling users to include any report object on the same page such as a CAD model, chart or text.
Production workers on the shop floor need to see how their processes are working and know how to improve them. “We’ve seen the same struggles on the production floor,” said Joseph Batts, Hexagon DataPage+ product manager. “We try to help with that by making Datapage+ a very easy tool to manage, forecast, and to see trending with the physical results for not just single parts like PC-DMIS provides, but a range of parts over a range of dates.” Workers need to make any number of decisions on that data, to see if they can catch parts before they come out of tolerance, Batts said.
“Looking at trend data, you can make a change to your manufacturing line, before a part starts to get out of tolerance and you have to start having to scrap materials,” said Batts. With DataPage+ users can measure a part and based on the interval desired, they can get as close to real-time responses as needed. Customers use a series of tools in DataPage+ to take measurements and adjust that interval, he said. The data goes into the Datapage+ SQL Server database, displays the tolerance and customers can use a shop-floor tool, DataMonitor, that comes with Datapage+ that allows users to monitor the process on the shop floor.
“All the operators can see these measurement values. They’re all color-coded and will display a series of run charts or measurement values,” Batts said. “We have an alarm system set up in the database so if a series of measurements are either turning out of tolerance or is already measured out of tolerance, it will sound an alarm.” The alarms show either red, yellow, or green lights on the shop floor to alert the operator to take a closer look at that part, do a re-measurement, he said, if a part is really out of tolerance, the operator needs to scrap it.
SPC developers face some challenges regarding SPC in the cloud, with industries like aerospace and defense still showing concerns over potential security issues, and with worries over intellectual property stored in such systems by medical device or pharmaceutical manufacturing customers. But in most cases, cloud-based systems actually offer greater security measures than are typical at most manufacturing operations, according to InfinityQS’ Wise.
Until recently, many customers needed to be educated on what SPC could offer, Wise noted. “All that has changed,” Wise said. “We don’t have to teach the value of looking at statistical data.”
The InfinityQS enterprise quality hub, ProFicient, is powered by a centralized SPC engine based on Microsoft’s SQL Server or Oracle’s relational database. The ProFicient SPC system offers users data collection and integration, real-time monitoring and analysis, workflow management and an advanced reporting suite. “We have some Web portals that can touch the data and back-end data that get to dashboards and to slices of the data,” Wise said. “We have ProFicient on Demand, a cloud solution.”
Highly installed in aerospace, where the company’s founders worked at Hughes Aircraft Company, Wise noted, InfinityQS also has a large share of SPC users in the food and beverage, pharmaceutical and medical device industries. A key issue with any SPC implementation is how the software developer sets up the system, and taking a process-centric approach is important to long-term success.
“What we’ve found is that proper setup is essential. One way is more part-centric, with setups for each part. With the other approach, we look at process growth,” Wise said. “What does that step do? We modify it accordingly, and we find that to be much more effective. We get the part’s life and the process life.
“SPC is more of a rich interaction with one’s process,” he added. “Much like our children, the better we know our SPC processes, the easier it is to deal with them.”
In automotive and aerospace, SPC is prized by quality control managers for its ability to help manufacturing management zero in on defects in the process and prevent scrapped parts. “Financial pressures are forcing manufacturers to only make saleable parts. There is no money in the budget to allow for throwing away or reworking bad parts,” noted Mitutoyo’s Fruit. “SPC can be a critical part of this process because SPC can detect when a manufacturing process is moving away from its target settings so adjustments can be made before bad parts are created.
“Can a company work without SPC? Yes, but it is likely to lose business to a competitor who uses SPC, the competitor making parts for less money or making higher quality which they can sell for a high profit margin.” Nearly all industries could benefit from SPC, he added. “Anyone who is making a product that has measurement specification should qualify. SPC not only applies to finished product it also applies to measured components added to make a finished product.”
With Mitutoyo’s MeasurLink, users get real-time online data collection with real-time SPC charts and analysis for operators. The system offers real-time quality control and supervisor reports and alerts for an organization’s entire manufacturing system. MeasurLink customer needs vary by continent and even country, Fruit noted, and the needs of customers drive new development. Based on current requests from customers, Fruit said new features in demand include standardization of data throughput for integration with other systems within a manufacturing environment (e.g. ERP systems); model-based engineering; improvements to data output flexibility (reports, text exports, etc.); and leveraging newer wireless technologies for data collection and gage tracking.
While SPC software applies to all parts manufacturing, Batts said the majority of Hexagon’s SPC customers are in automotive manufacturing. Hexagon’s DataPage+ is used extensively for automotive in-line measurement stations performing Body-in-White scans that take millions of points for each scan. ME
This article was first published in the July 2014 edition of Manufacturing Engineering magazine.
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