The Effects of Cryogenic Treatment on Twist Drills Drilling a Titanium Alloy

Drill Brands:

Precision Twist and Union Butterfield (8% Cobalt Hi-Speed M-42 drills). Both brands responded similarly.

Material Drilled:

The Machining Data Handbook recommends a removal rate of .03 in³/min. when drilling titanium. When this rate was doubled, the deep cryogenically treated drills clearly indicated a significantly smaller number of drills were required to drill the same number of holes.

Feeds and Speeds:
Speed= 620 rpm; Feed= .002ipr (inches per revolution) with a target drill life of 20-30 holes.

fewer drills 

39 fewer drills (27%) were necessary to drill the same number of holes. This results in 39 fewer tool changes, significantly reducing machine downtime.

Resharpening Removal Amount Cut By ½

Industrial cryogenic users report that cryogenically treated drills require a material removal rate of less than ½ of the normal material removed in re-sharpening. This reduces the total number of drill bits required by one half.

Data attained from Master’s Thesis by Johnny Chung-hwa Chao, Arizona State University, 1980.