The Difficulties for Titanium Alloy CNC Machining

Owning to some features of titanium alloy,it makes difficult to machining.As the other answer  has stated, the use of good, sharp tools is a must.

What makes Titanium difficult to machine?Taking the universal alloy of titanium ---Grade 5 (6al4v) as an example.

1) It tends to work harden --- that is, when cutting tools rub against it, it becomes harder and more difficult to cut.  That is why it is essential to use sharp tools.  As soon as the tool shows signs of decreased sharpness, replace it immediately.  It will not gradually go from sharp, to kinda sharp to not really sharp but adapt to replacement time --- more like, it will go from sharp.You first notice it's not quite as sharp anymore to disaster in quick order.  Erron on the side of replacing tools too soon.

2) It is in Poor thermal conductivity (for a metal).  You must use coolant when machining titanium.  Because the heat does not dissipate very well throughout the metal, the heat tends to stay at the locus of the cut --- and go into the tool -- and wear it out.

3) Titanium can chemically bond with cutting tools, causing built up edges on the tool, decreasing the effectiveness of the tool.

4) Titanium is springy, it moves away from the cut if you take cuts too light --- this just ends up work hardening it.

  For milling, using flood coolant and a fine pitch roughing end mill made from cobalt steel or some type of powdered metal with an ALTin or Tialn coating.  For finishing, using a carbide or cobalt end mill with at least four (preferably more) flutes. 

   For drilling, using screw machine length 135 degree split point m42 cobalt drills.  Using a squeezy bottle of olive oil and keep a forceful stream going the entire time of the cut.  It is very important not to dwell -- either push hard down or retract the drill entirely --- otherwise you'll end up dwelling, rubbing and work hardening.Tapping is difficult if you do not have the correct tools.