普通麻花钻受其固有结构的限制,其几何形状存在着某些缺陷。通过对其切削部分的修磨,可以得到一定改善。“群钻”就是一种行之有效的修磨形式。如果采用比普通高速钢性能更好的新型刀具材料,或变革麻花钻的结构,在此基础上再将钻头切削部分修磨成“群钻”钻型,则钻孔效果将进一步提高。近年来,新刀具材料的研制技术和刀具的制造技术有了很大的发展,故使变革麻花钻的材料 The ordinary twist drill is limited by its inherent structure, and its geometry has certain defects. Through its cutting part of the grinding, you can get some improvement. “Group drilling” is an effective form of grinding. If the use of new materials than ordinary high-speed steel performance better, or change the structure of twist drill, drill bit and then re-ground into a “group drill” type, the drilling effect will be further improved. In recent years, the new tool material development technology and tool manufacturing technology has made great progress, it makes the change twist drill material