TABLE OF CONTENTS The purpose of this chapter is to present the latest techniques for high-efficiency rough milling of titanium alloys. Little progress had been made in rough maching of titanium alloys until February of 2004.
This book does not get into the details of standard and sound milling practices for general machining such as the notion of keeping at least two cutter teeth in the work. These practices are well described in many other publications, and it is presumed that your machinists are well versed in these general milling methods.
This chapter opens with a discussion of the traditional practices for rough milling of titanium alloys. Limitations caused by chatter are discussed. This is followed with some recent breakthroughs in rough milling that reduce milling time by about one-third.
For the past 40 years, nearly all rough milling of titanium alloys has been with cobalt cutters (made from M42 cutter material) at speeds up to 60 sfm (18 m/min..) With 0.005 in. (0.127 mm) chip loads, this gives a minimum of 1 hour of cutter life even with the cutter buried in the material. Chip loads per tooth that vary from 0.002-0.012 in. (0.051-0.305 mm) are used. If chip loads of less than 0.002 in. are used, there is danger of work hardening and of overheating.
The traditional cutter material for roughing of titanium alloys is (M42). Cobalt cutters are used because carbide does not hold up well on the uneven surfaces of...
