HIGH-SPEED CUTTING WITH ENDMILL TOOLS MADE OF CERAMICS

近年来，陶瓷材料的力学性能有了很大的提高，尤其是韧性的提高。明确了Si_3N_4基陶瓷作为刀具在灰铸铁高速加工中的应用领域。特别是针状β晶自增强Si3N4和其他Si3N4基陶瓷刀具在恶劣的切削条件下表现出良好的性能。研究了刀具几何形状对陶瓷立铣刀在高速车削条件下的切削性能的影响。结果表明：(1)陶瓷立铣刀加工的工件表面具有较好的螺旋角。(2)陶瓷球头立铣刀在高速(V=1500m/min)条件下的耐磨性优于低速(V=300m/min)。(3)陶瓷球头立铣刀高速加工的加工表面光滑，陶瓷球头立铣刀可以成功地应用于灰铸铁的高速铣削加工。

Recently, the mechanical properties of ceramic materials were improved, especially their tougthness. The applicationfield of the Si_3N_4-based ceramics as cutting tools has been specified in the high-speed machining of gray cast irons. In paticular, self-reinforced Si_3N_4 with acicular beta-grains and other Si_3N_4-based ceramic tools exhibited high performance under severe cutting conditions.In this note, a trial using ceramic endmill tools made of Si_3N_4-based material has been described. The effect of tool geometry on the cutting performace of the ceramic endmill tool under high-speed cutting conditions was investigated.Results obtained can be summarized as follows.(1) The finished surface of the workpice machined by the ceramic endmill tool was better for a tool with a helix angle.(2) Wear property of the ceramic ball-endmill tool was superior under the high-speed cutting condition (V=1500m/min) to that under the low-speed condition (V=300m/min).(3) The finished surface obtained in high-speed cutting by the ceramic ball-endmill tool was smooth, exhibiting low degree of roughness.(4) The ceramic ball-endmill tool can be successfully applied to high-speed milling of gray cast iron.