Ceramic Industry

Kiln Connection: Making the Connection

July 21, 2000
It is a genuine pleasure to introduce a new bimonthly column here at CI—The Kiln Connection—and I couldn’t be more pleased to be its author. I’ll provide real world information and practical tips that you can use in your factories to improve the yield and quality of your products, reduce energy usage and increase the consistency of operation.

I hope that my combination of theory with matter-of-fact techniques will help you do a better job in your firing operations. Case histories, discussions of kiln designs, retrofit solutions, and kiln buying guidelines will all be covered in future columns. I also welcome your questions and ideas—just e-mail me at Ruarkeng@aol.com and a response will be sent via e-mail, or maybe even within a column.

The Role of Kiln Management

One area that could certainly benefit from discussion is kiln management—considering it as part of the overall production process. So often in factories there seems to be a polarization between the ceramic group responsible for the raw materials and processing, and the kiln operations group responsible for operating the kilns. It’s kind of like Lee Iococca’s observation when he took over at Chrysler: “The engineering and production guys, who should have been in bed together, hadn’t even been on their first date!”

The ceramic engineers should work hard to provide the best compositions, formed with low residual stresses. By the same token, the kiln operators should adjust and maintain kilns so that they provide the widest possible window for stress free firing. When these two groups work together effectively, the result is manufacturing excellence. The only way to get to this point is to let data tell the story. Use of data, rather than conjecture, will define the problems and point the way to solutions.

Acquiring the Data

Data acquisition systems for shuttle kiln and tunnel kiln firing can do wonders in many cases. Fixed kiln thermocouples only provide a general idea about the true firing characteristics that your fine products see. For example, take a look at Figures 1 and 2.

Figure 1 shows temperature peaks caused by burner location and ratio problems, and Figure 2 illustrates the results of fine-tuning. For the manufacturer in this case, using a data acquisition system has improved yield through less ware distortion and better consistency of fired properties. Using only the kiln thermocouples, we could not see any of the ware and burner interactions and were “working in the dark” to figure out what was going on. However, not only does the data acquisition system provide a detailed firing history, it can also provide information regarding heating rates through critical firing periods, simple calculation of differential temperatures, and comparisons to the desired firing curve. Files can be e-mailed from one plant to another for collaboration, or to the kiln manufacturer for expert interpretation.

In summary, I’d like you to look to this column for solid theory plus pragmatic solutions. We should all work hard to be customer-driven in the true sense of the word, paying attention to internal and external customer requirements. And that applies to us at CI as well. So please, tell us what you think—good or bad. We’ll work to meet, and even exceed, your expectations. You can count on it.