# What does statistical process control really do?

## Some sophisticated math can help you make your manufacturing more consistent and identify production problems sooner.

02/12/2013

You’ve heard of SPC. Statistical process control applies statistical methods to control manufacturing processes. You can go look at all the equations yourself, and you’ll see it’s actually pretty cool math and a practical application of mathematics in manufacturing.

But, what does it really do? SPC is like a lot of things, people have heard about it but few do anything with it. And, when someone actually does something with SPC it’s often a math or quality geek who’s doing something no one else in the plant understands. So, if that’s your take on SPC you’re not alone. I’m not going to be able to explain all of SPC in just a blog post or two, but I would like to talk about what SPC can do in the real world. That is, I’d like to talk about the actual real-world benefits of SPC.

First and foremost, SPC, particularly real-time SPC, can help you avoid failures. There’s lot of math behind this, none of which I’m going to go into, thankfully, but the idea is simple: the analytical capabilities built into SPC can indicate when a process is about to go out of control. And, if you know it’s about to go out of control, you can do something about it before it goes out of control. That helps you significantly reduce quality issues and helps you reduce downgrades and rework all by allowing you to identify problems before they’re problems, and then eliminate, or at least minimize, the failures.

Secondly, SPC helps you improve product consistency because it helps you look at the process at lot more closely so you can start ferreting out the causes of product variability. Maybe you’ll find processes that you thought were very stable aren’t as stable as you thought. SPC lets you determine the degree to which they’re stable or unstable, and then take actions to improve the process. And, SPC gives you the information to figure out if the steps you’re taking actually work. All that helps you improve product consistency and reduce product variability all by helping you reduce variability in your manufacturing processes.

And, last but not least, SPC, particularly historical SPC, helps you with your continuous improvement initiatives. Like most people, you probably have some type of continuous improvement program underway, like six sigma, lean manufacturing, or whatever. SPC helps you analyze where you need improvements and what types of improvements you need to make. As you make those improvements, SPC helps you verify that the improvements are working and things are actually getting better just as you hoped. There’s a lot to this piece as SPC can help in a wide variety of ways in all aspects of a continuous improvement program.

So, forget all the cool math, just trust that it all works. Concentrate instead on the real-world business benefits. SPC helps you avoid failures. Fewer failures reduce quality issues and rework. SPC helps reduce process variability which reduces product variability and improves product consistency. And, SPC helps with just about any aspect of continuous improvement you can think of. All in all, not a bad day’s work for a bunch of math geeks. Take a look at SPC, it’s well worth it.

This post was written by John Clemons. John is director of manufacturing IT at MAVERICK Technologies, a leading system integrator providing industrial automation, operational support, and control systems engineering services in the manufacturing and process industries. MAVERICK delivers expertise and consulting in a wide variety of areas including industrial automation controls, distributed control systems, manufacturing execution systems, operational strategy, and business process optimization. The company provides a full range of automation and controls services – ranging from PID controller tuning and HMI programming to serving as a main automation contractor. Additionally MAVERICK offers industrial and technical staffing services, placing on-site automation, instrumentation and controls engineers.

Consulting-Specifying Engineer's Product of the Year (POY) contest is the premier award for new products in the HVAC, fire, electrical, and...
Consulting-Specifying Engineer magazine is dedicated to encouraging and recognizing the most talented young individuals...
The MEP Giants program lists the top mechanical, electrical, plumbing, and fire protection engineering firms in the United States.
Integrating electrical and HVAC for energy efficiency; Mixed-use buildings; ASHRAE 90.4; Wireless fire alarms assessment and challenges
integrated building networks, NFPA 99, recover waste heat, chilled water systems, Internet of Things, BAS controls
40 Under 40; Performance-based design; Clean agent fire suppression; NFPA 92; Future of commissioning; Successful project management principles
Transformers; Electrical system design; Selecting and sizing transformers; Grounded and ungrounded system design, Paralleling generator systems
Commissioning electrical systems; Designing emergency and standby generator systems; VFDs in high-performance buildings
Tying a microgrid to the smart grid; Paralleling generator systems; Previewing NEC 2017 changes
As brand protection manager for Eaton’s Electrical Sector, Tom Grace oversees counterfeit awareness...
Amara Rozgus is chief editor and content manager of Consulting-Specifier Engineer magazine.
IEEE power industry experts bring their combined experience in the electrical power industry...
Michael Heinsdorf, P.E., LEED AP, CDT is an Engineering Specification Writer at ARCOM MasterSpec.
Automation Engineer; Wood Group
System Integrator; Cross Integrated Systems Group
Fire & Life Safety Engineer; Technip USA Inc.
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.