Kyocera's Ceramics and Cermets Revolutionize Industrial Metal Cutting Company Expands North Carolina Plant To Meet Global Demand

Today's manufacturers are under intense competitive pressure to produce higher quality parts at ever-faster production rates. In the field of metal processing, which serves as the foundation for many traditional manufacturing industries, this need is fueling demand for high-technology cutting tools that can cut metals with unprecedented levels of speed and precision. Engineers using today's advanced processing machines are increasingly adopting ceramic and cermet cutting tools because of the dramatic advantages they can offer in cutting speed, quality, maintenance requirements and longevity.

Kyocera Expands U.S. Capacity
Kyocera Industrial Ceramics Corporation has produced the Ceratip line of ceramic and cermet cutting tools in Mountain Home, North Carolina since 1979. In July 1996, the company redoubled its commitment to this technology with a 40,000 square foot addition to its production operations there. Long known for its craftsmanship and work ethic, North Carolina also places Kyocera's production center in close proximity to the truck lines, rail heads, and airports necessary to serve world markets. The company's expanded facility is planned as a manufacturing center for ceramic cutting tools, with the potential of supplying the world's ceramic cutting tool needs.

Cutting Tool Inserts -- General Description A cutting tool insert, when attached to an industrial cutting tool, serves as the "blade" for high-tech cutting operations. These inserts are typically no larger than a fifty-cent piece and often feature geometric shapes to provide a number of cutting edges. Because of their extreme hardness, physical stability, heat resistance and other material properties, ceramic cutting tool inserts are finding acceptance in some of industry's most critical metal-cutting tasks.

Ceramic Cutting Tool Applications Machining Large Workpieces. A primary advantage of ceramic cutting tool inserts is the tremendous time savings they can offer. One example is the machining of large workpieces, which generate high surface feet per minute (SFM) and metal-removal rates (in3/min). Ceramic inserts can run at SFM rates up to eight times faster than traditional cemented carbide tools on large workpieces such as truck hubs, turbine shafts and the processing rolls used in steel mills. The last example includes workpieces so large they must be loaded onto the lathe using a crane. With ceramic cutting tools, these rolls can be machined in a single day -- versus three to four days with cemented carbide cutting tools. Best of all, this productivity improvement can be made without the capital expense of new machinery and with the bonus of a better surface finish on the end product.

Another large-workpiece example is the machining of cast iron truck hubs. For cast iron workpieces in the normal hardness range (180-350 Brinell hardness), silicon nitride ceramics such as Kyocera's KS6000 grade permit cutting speeds up to 5000 SFM and beyond -- a tremendous advantage over carbide and coated carbide cutting tool inserts. Silicon nitride offers higher toughness than most other ceramics and can be used to cut large cast iron parts even where scale and interrupted cutting may occur. Additionally, Kyocera's silicon nitride cutting tools can be run with or without coolant.

Hard Turning Operations. Ceramics can offer significantly reduced downtime and better-quality surface finishes in the turning of hardened workpieces. Known as hard turning, this application is one of the easiest uses for ceramic cutting tools. Kyocera defines it as the machining of materials rated 50 to 65 on the Rockwell "C" scale. In this hardness range, cutting forces are up to 80% higher than traditional "soft" machining processes, with typical workpieces including gears, bearings and shafts. Kyocera's CER2 and A65 hot-pressed ceramic cutting tools are widely used for these applications and are literally replacing the traditional grinding process in a growing number of applications. One reason is that hard turning generates less heat in the workpiece than grinding, due to ceramics' ability to put most of the heat into the chips -- not into the workpiece. Traditional grinding, in contrast, creates extreme heat that requires coolant and may cause surface imperfections. (Ceramics do not require coolant for hard turning, nor is coolant recommended.)

Shorter cutting time is again one of the primary benefits of hard turning with ceramics. A grinding process which requires six to eight hours on a typical part can often be accomplished by hard turning in 15 to 20 minutes, allowing fewer machines to do more work. Hard turning also requires no coolant, pumps or filters, which enhances a machine shop's "housekeeping." Additionally, ceramic cutting tool inserts can be changed in about 1% of the time needed to change an industrial grinding wheel. Cutting speeds for a 60 RC hardness steel workpiece are in the 400 SFM range, with a typical feed rate of .004 inches per revolution. Most computer-numeric-controlled equipment is very capable of these cutting conditions, making the advantages of hot pressed ceramic grades A65 and CER2 easy to enjoy. As an incidental benefit, the noise generated from hard turning is significantly lower than the loud process of grinding.

Large-Quantity Metal Removal. The incremental time savings offered by ceramic cutting tool inserts add up to significant productivity enhancements in large-scale applications. A typical user in this category may be an automotive supplier making 250,000 units of a single brake rotor. Other automotive applications include hubs, shafts, turbocharger parts and engine blocks. The most commonly applied ceramic in these operations is silicon nitride, which Kyocera supplies for such uses as the high-speed removal of cast iron. Kyocera's KS6000 grade is capable of milling and turning cast iron even under unfavorable conditions, such as interrupted cuts, rough scale or high feed rates. In addition, KS6000 can be used with or without coolant, depending on specific needs.

Although ceramic inserts require the customer to do more up-front engineering, the greatly increased cutting speeds pay for this investment many times over. Engineering considerations include safe clamping devices for high-speed cutting; improved machine capabilities to facilitate higher operating frequency and shorter cycles; and a thorough review of the required insert geometry and machining sequence.

Material Limitations
All cutting tool materials enjoy applications in which they excel and others in which their uses are limited. Specific limitations of ceramic cutting tools include the following:

• Low resistance to mechanical shock (excluding silicon nitride grades);
• Limited geometric configurations (i.e., ceramic material properties prohibit insert designs featuring thin cross sections and molded chipbreakers);
• General lack of ceramic expertise by end-users.

Newer grades of ceramics, different machine practices, and end-user training are overcoming many of these limitations and creating more applications for ceramic tool inserts each year.

Cermet -- the Ceramic-and-Carbide Hybrid
Some cutting applications remain unsuited to pure ceramic tool inserts, yet nevertheless demand higher cutting speeds and longer tool life than conventional inserts provide. This middle ground is where the ceramic-and-carbide hybrid known as cermet offers significant advantages. Cermets (ceramic and metal carbides) form a new classification of cutting materials. These materials are composed of titanium nitrides and titanium carbides with various carbides included for increased toughness. Kyocera has long been the leader in cermet technology and continues to expand the use of cermet cutting tool inserts.

Although cermets are manufactured through the same basic process as carbide products, they offer better wear resistance, longer tool life, higher cutting speeds and superior surface finishes in comparison with coated carbide alternatives. Coated carbide inserts are still used where an added degree of toughness is required over cermet tools; however, where high cutting speed and wear resistance are the primary requirements, cermets are superior.

Cermet cutting tools consist of the same basic material that is used to coat carbide cutting tools. When a coated carbide tool is used, the coating gradually wears off -- thus diminishing the insert's wear resistance. In contrast, cermet is a homogeneous material which does not lose its wear resistance. Cermets can be applied on most commonly machined materials including carbon and alloy steels, stainless steels, tool steels, cast irons, powdered metals, nodular irons, and nonmetallics.

Cermet Cutting Tool Applications
Grooving. This may be the ideal application for cermet cutting tools. The majority of grooves are put into a pre-machined portion of a workpiece, with the cutting tool fed straight in and pulled straight out. Wear resistance is the key factor to success in this application and cermets work extremely well. Wear resistant grades such as TC-30 and TC-40 are applied for most grooving applications, with tougher cermet grades like TC-60 applied for such materials as stainless steels and nodular irons. Recent advancements include the addition of cermet grades for both cut-off and plunge-and-turn operations.

Turning and boring. Cermets can perform these operations in areas ranging from semi-roughing to fine finishing. Cermets specialize in helping to meet demanding workpiece requirements -- such as close tolerances and/or high quality surface finishes. In addition, cermets can be run at higher speeds than carbides, with a lower affinity to most workpieces. Kyocera offers cermets in chipbreaker designs to optimize the performance of the cermet grades throughout the stated application range.

Threading. These applications are perhaps the most sensitive of all cutting tasks, subjecting tools to extreme heat on a very small threading point. Cermet tools withstand this heat due to their higher "hot hardness" than carbide or coated carbide tools. Cermets can also be run at higher speeds, resulting in better surface finishes and reduced likelihood for the workpiece material to accumulate on the cutting edge -- a cause of gradual failure in other cutting tool materials. The result will be a cleaner, higher-quality thread.

Milling. New grades, in conjunction with new insert and tool designs, now allow cermets to be used in more milling applications -- including some once considered impossible. Many of the advantages listed above apply directly to milling operations, including higher speeds, longer tool life, better surface finishes, and tighter tolerances. Generally speaking, these advantages ensure a strong future for ceramics and cermets in a growing range of metal cutting operations -- particularly amid today's demands for higher productivity and efficiency in all aspects of manufacturing.

About Kyocera
Kyocera Industrial Ceramics Corporation supplies the CeratipR line of ceramic and cermet cutting tool inserts, as well as industrial and automotive ceramics; ceramic substrates; ceramic fiber optic components; liquid crystal displays; and thermal printheads. This wholly-owned Kyocera subsidiary is headquartered in Vancouver, WA, with production operations in both Vancouver and Mountain Home, NC.

Kyoto, Japan-based Kyocera Corporation, the Kyocera Group's global parent company, is a world-leading producer of advanced ceramics, with high-tech products ranging from advanced materials and components to telecommunications equipment and services.