Wednesday, October 10, 2007

The Right Way For Milling Titanium

Milling titanium is like milling other hard-to-machine metals in that a small increase in cutting speed can lead to a big increase in edge wear. Speed and heat will somehow become directly proportional to each other when it comes to hard metals. Working with titanium is different from milling an ordinary metal. For the reason that heat conduction is greater for hard type of metals that its molecular structure are closer and rigid than that of a regular metal for machining.

Shops cutting titanium are familiar with the practice of using low radial immersion to control heat. In a low-radial-immersion pass, the radial depth of cut is much less than the radius of the tool. As a result, every cutting edge spends more time out of the cut than in it, giving each edge relatively little time to heat up and much longer to cool down.

This practice works so well at controlling heat, that many users fail to realize how much extra speed they may be able to observe. The light depth of cut exclude a high metal removal rate, but the shop make finishing passes using this method can partially compensate by leaving the recommended speeds behind.

The rules from the experts:

  • When radial depth is less than 25 percent of diameter, increase the sfm by 50 percent (over the nominal speed used for heavier cuts).
  • When radial depth is less than 10 percent of diameter, increase the sfm by 100 percent

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