Advertising in MoldMaking Technology offers
Issue link: https://mmt.epubxp.com/i/485569
Cutting Tools 44 MoldMaking Technology April 2015 same way as toroidal tools, and use the same stepovers and depths of cut. They can cut slots in hardened materials using trochoidal tool paths or new tool paths that control the cutter engagement angle. As explained earlier, it is important to make sure the tool is about 50 percent of the slot width to allow for enough movement and to ensure that the angle of engagement does not increase and generate too much heat. Graphite Cutting The abrasiveness associated with cutting graphite quickly wears out standard carbide tools, and then the worn tool will not accurately cut the necessary complex geometries. Cutter path and technique are not as critical in graphite cutting applications, so it is usu- ally the electrode shape that dictates the type of cutter. Diamond- coated tools are widely used in these applica- tions because they offer added wear resistance. Diamond is grown on the carbide tool, creat- ing a very hard, wear-resistant layer that greatly extends tool life. The life of a diamond-coated tool ranges from 10- to 30-times longer than that of uncoated carbide cutters. For example, a ¼-inch–diameter, uncoated carbide, ball-end tool typically can cut a 6-by-6-inch complex graphite electrode for about four hours before its razor-sharp, detailed features start flaking at the edges. A diamond-coated tool can last more than 98 hours without any flaking of the edges. Some graphite shapes such as thin ribs, sharp geometries and small part sizes specifically require tools with very sharp cutting edges. Even a 2-to-3-micron-thick diamond coating can FOR MORE INFORMATION: RobbJack Corp. 844-299-2540 / mike@robbjack.com / robbjack.com CONTRIBUTOR Mike MacArthur has worked for RobbJack Corp. for 20 years. He currently is vice president of engineering, and leads research and development efforts, as well as technical sales and customer support. VIDEO: Toroidal Tools for Tight Areas Toroidal end mill in hardened steel mold machining of helical bores in 54-HRc H13 steel. short.moldmakingtechnology.com/toroidal improve tool life and maintain the sharp edge in such applica- tions. Because this thinner diamond is less expensive, it is ideal for lower-production applications that don't require tool life to be as long as that provided by the typical 18-micron thickness. Technology such as this means moldmakers with smaller production quantities that are looking for less-expensive tools don't have to sacrifice tool life for lower cost. They can still get the advantages of true-diamond-coated carbide tools, but also take advantage of the fact that thinner diamond coatings will satisfy the requirements of their particular applications. Diamond coatings today are available in thicknesses ranging from 2 to 25 microns. The best cutting tool for a particular application should not only be determined by the material being cut, but by the type of cutting and milling technique as well. By optimizing the cutting tool, speeds and feeds, and programming techniques, parts can be made faster and with lower operating costs. These magnifcations show cutting tool edges that are (left to right) uncoated, coated with a 2-4-micron-thick diamond coating and coated with an 18-20-micron-thick diamond coating. LEARN MORE Visit our Cutting Tools Zone for more information on end mills, drills, inserts, spindles, toolholders, fuids and coatings. Go to moldmakingtechnology.com/ zones for a complete list.