Continuous on-line moisture measurement enables ceramic fuse barrel manufacturer to substantially increase production capacity

Expert in the field of high technology ceramics, CeramTec is using an NDC Infrared Engineering MM710 near-infrared gauge system at its manufacturing plant in Colyton, UK for on-line measurement of moisture in the manufacture of ceramic fuse holders. Following a successful trial, CeramTec has been using the system since Spring 2003 to look at clay consistency and mixing time and is already achieving benefits in terms of improvements in process control, efficiency and product quality when compared to the off-line techniques used previously.

With a presence in 12 countries, the CeramTec high technology ceramic group has more than100 years of material, production, and application experience. The group produces in excess of 10,000 specialist ceramic products for diverse applications including electronic, electrical & thermal, medical, metalworking, mechanical equipment, automotive, chemical and sanitary fittings. CeramTec’s production site in Colyton, Devon manufactures tubes and rods for fuse resistors, gas igniters and laser-machined substrates. The plant produces most of the world’s fuse holders.

NDC Infrared Engineering’s relationship with CeramTec began in Autumn 2002 when they worked with CeramTec’s Seramban facility in Malaysia to provide a gauge to measure moisture in extruded clay, as used in the manufacture of formers for the latex glove industry.

In the case of the Colyton plant, NDC Infrared Engineering has developed special MM710 measurements for CeramTec especially for the two types of ceramics used - Steatite and Cordierite. Steatite and Cordierite have a low coefficient of thermal expansion and excellent resistance to thermal shock. They are relatively low cost, have good electrical insulation properties, have moderate mechanical properties and temperature resistance, and can readily be formed in a variety of shapes. In particular they can be made in high volume through cost-effective extrusion or dry-pressing methods.

“Our main reason for investing in an on-line measurement system was to try and get more out of our existing manufacturing system thereby increasing the total capacity. The new gauge also means we are able to get a moisture level for a whole batch and not just a spot reference as had previously been the case. Furthermore, NDC Infrared Engineering’s ability to customise its MM710 for our application has meant that we have had minimal calibration effort with an improved measurement repeatability and an overall improvement in ROI,” comments Dermot Gooding, General Manager of CeramTec’s Colyton Plant.

CeramTec has the NDC Infrared Engineering MM710 sensor installed over the main clay out-feed belt for accurate measurement of moisture on-line. Moisture measurement is essential for producing ceramic fuse holders, as this a key parameter for controlling the forming process. If moisture levels are not controlled i.e. too much or too little moisture is present, then the clay will behave differently in the extrusion process meaning abnormalities occur in terns of product size. Mr Gooding explains: “Because the manufacture of our products is precise down to hundredths of a millimetre it is vital for us to have an exact, consistent level of moisture present in the process to ensure constant quality of our end product.”

The MM710 gauge is positioned after the extrusion and cutting stage in the manufacturing process. The NDC Infrared Engineering system helps control moisture levels of the clay prior to forming . The target moisture must be maintained to a tolerance of + / - 0.5% and the MM710 gauge readings are displayed on an operator interface in the control room for decision-making by the shift manager. Should the moisture measurement start to drift from the target range, the shift manager can take immediate action to adjust the water content in the manufacturing process.

Mr Gooding comments: “Our previous off-line moisture measurement was a 'loss-on-drying' test and reporting method. This technique adds up to three quarters of an hour to each batch time. By eliminating this time loss, we have the potential to increase production by 1/7th. This enables us to meet current demands with existing equipment and resources instead of purchasing new equipment which would cost us about £175,000 or by adding another shift to our production schedules.

The 100% inspection achieved with a continuous on-line gauge gives us useful information about the variability of the mix. It also allows the operator to take decisions on the product and rule out problems with the clay properties immediately, instead of waiting for off-line results. This allows us to make our process control more responsive and reduce wastage. Near-infrared measuring systems and in-particular the MM710 gauge are an attractive option because of their greater accuracy and reliability and their adaptability to continuous processes,” Mr Gooding continues.

CeramTec plans to use the MM710 to look at clay consistency and mixing times in their manufacturing process. The MM710 provides objective data for further process analysis and testing.

“The CeramTec group already has a strong relationship with NDC Infrared Engineering through the work carried out at our sister plant in Malaysia. When we recognised our problems with offline measurement at the Colyton plant, this strong relationship and the quality of the company and the solution made the MM710 the obvious choice,” comments Mr Gooding.

“We see the successful integration of the NDC Infrared Engineering MM710 gauge as an integral part of consolidating our position as an expert high technology ceramic manufacturer, through the improvements in process control and productivity,” Jurgen Langer, Managing Director, CeramTec UK.