TURNINGTAPPINGHOLEMAKINGSOLID END MILLINGINDEXABLE MILLING High-Performance Solid Carbide End Mills Trochoidal Milling TTHelix Angle and Chip Thickness The chip thickness (h) depends on the helix angle of the cutting edge. If the feed fz is constant, the chip thickness gets thinner as helix angle rises. That means with more helix angle, the chip gets thinner — or you can rise feed rate to increase productivity and load to the cutting edge. TTCalculation of Chip Thickness The chip thickness (h) is not constant, but defines the load of the cutting edge. By reducing the load on the cutting edge, machining at higher speeds is possible through the machining parameters. For easier calculation, use an average chip thickness hm. When calculating machining data this way cutting data may be compromised because the workpiece is often a different shape. fz fz fz B b ap c fz fs/2 fs/2 hm h hm [mm] = average chip thickness fs [°] = engagement angle hm= 360º •p • fsaeD• fz • sin c ae [mm] = width of engagementD1 [mm]=outer diameter tool fz [mm] = feed per tooth c [°] = lead angle l [°] = helix angle * * Solid End Mills: c = 90°-l NOTE: It makes no difference if the tool is solid or an indexable milling tool. B56 widia.com