Process Control: Building Profits and Growth with Statistical Process Control
You have undoubtedly been exposed to the concept of statistical process control, or at least to the terminology. Over the past several decades, there has been a relatively quiet, and decidedly incomplete, revolution in product quality and process control in the ceramic industry. This is a reflection of what has happened in industry as a whole. American industry has not generally been the leading force in this revolution, and the ceramic industry has been less proactive than many others.
Be that as it may, fierce global competition and substantially higher quality and value expectations by users and consumers dictate that sheer survival, let alone growth and prosperity, is increasingly dependent on superior product quality and value, excellent customer service, very efficient manufacturing and cutting edge technology. Statistical process control is a tool that can contribute toward meeting these needs. Our goal in this new Ceramic Industry column is to explore statistical process control (SPC) and related issues as they apply to the ceramic industry. The topic is not a particularly glamorous one, but it holds the potential for enormous economic impact.
Where it All BeganIn the 1950s and 60s, a then somewhat obscure gentleman by the name of Dr. W. Edwards Deming had the audacity to propose to American industry that the use of both a radical management philosophy and statistical tools applied to process control could not only improve product quality and reliability, but could also concurrently cut costs and maximize profits.
Everyone knew that this could not be so. Conventional practice (and wisdom) was based on inspecting quality into products, and attaining higher quality meant rejecting more product. Higher levels of quality thus increased costs and reduced yields.
In America at that time, Deming’s ideas fell on deaf ears. Industry generally was having trouble meeting consumer demand, and the American public was more concerned with obtaining goods than it was with the quality of those goods. Expectations then were quite a bit lower than they are today. In addition, performing statistical analyses was very time-consuming. The personal computer and associated powerful software, which we take so much for granted today, were many decades in the future.
Deming did find an avid audience, however. That audience was in Japan, and the rest is history.
A Broad ViewThere is a tendency in industry to focus somewhat narrowly on the statistical end of SPC, and that can be non-productive. In fact, some companies who have tried SPC quickly abandoned it because they failed to understand all that is required for success. SPC is merely a tool and certainly not an end in itself. Although it can be a powerful tool, it cannot function effectively alone. It requires personnel highly trained not only in SPC, but also in ceramic technology, process equipment, and in other areas as well. Above all, it requires genuine, strong, unwavering commitment and a great deal of perseverance.
Intelligently used, SPC can greatly aid in the achievement of seven critical goals:
- Generate greater profits
- Improve product quality
- Increase manufacturing capacity
- Enhance customer satisfaction
- Improve product delivery
- Cut manufacturing costs
- Build employee pride
SPC and Ceramic ManufacturingSPC is to process control what accounting is to financial control. SPC is a mathematically based tool that allows us to study a set of manufacturing processes, determine levels of inherent variability, find potential correlations and even cause-and-effect relationships between process variables, determine whether or not a process is in “control,” and, in the best of circumstances, find ways to improve and optimize processes and to minimize variability. Today, all of this is made feasible and practical by powerful and relatively easy to use PC-based software programs that include sophisticated graphical presentation capabilities.
However, ceramic processing is typically very complex, with a very large number of process variables. The interactions and interrelationships between these variables make analysis much more difficult. Ceramic processing is thus much different from assembly-type manufacturing. Different analysis tools, capabilities and management philosophies are required. Four knowledge bases or capabilities are necessary for attaining the seven goals listed earlier:
Knowledge Base 1: A thorough knowledge and understanding of ceramic processing technology. It is simply not possible to control ceramic processing, even with the most sophisticated statistical process tools, without personnel who understand ceramic technology. A high proportion of the staff in the manufacturing organization needs to possess such understanding and knowledge, and this is rarely the case in the ceramic industry.
Knowledge Base 2: Broad application of statistical tools for process control. Statistical tools are very useful for making sense out of process data, for sorting out important relationships, for measuring and ultimately minimizing process variability, for optimizing processes, and for improving control. Modern computer software makes very powerful tools readily available and surprisingly easy to use (and misuse).
Knowledge Base 3: Development of ceramic process control programs. Process control is achieved by melding these first two knowledge tools into a program of effectively controlling and enhancing process control.
Knowledge Base 4: A new management philosophy. Perhaps the most controversial and least adopted of Deming’s ideas relates to his management philosophy. To challenge your imagination and preconceived notions, take a look at www-caes.mit.edu/products/deming/14-points.html. Failure to embrace the spirit of these concepts can cripple success.
In future columns we will explore these aspects of process control in greater depth.