Tooling Tips for Exotics

While exotic materials typically provide improved wear characteristics and better service life for in final product, they can present particular challenges during machining. In his article, “Considerations for Machining Exotics,” from a previous issue of Production Machining, Joseph Gentile, product manager at Hangsterfer’s Laboratories Inc., details a number of strategies that can ease this burden for the manufacturer. A specific area he addresses is strategies for extending tool life.

• -  Tools must be mounted at the correct and recommended center line height. Some grooving tools get mounted above centerline.
• -  Indicate the tools mounted in the lathe turret in all axes.
• -  If possible, do not use shims to adjust tooling height.
• -  Fix the turret centerline.
• -  Mount boring bars in a good sleeve, not multiple sleeves, with good, flat bottom set screws so they will not vibrate loose.
• -  Make sure the conical washers in the CNC mill spindle drawbar are not cracked or broken. The toolholder can be pulled out of the tapper with tough materials.
• -  Indicate end mills in more than one place to confirm centerline turning (0.0005 is recommended).
• -  Use the shortest toolholders possible with the shortest tools.
• -  Hold drills and center drills tight. Regular drill chucks are not sufficient for a long running job. Double angle collets can slip while drilling Hastelloy if it is running at the recommended speeds and feeds. Special adapters are made from drill rod or compression adapters.
• -  Remove all obstacles in the way of the coolant. Getting the correct amount of oil or coolant to a small drill without the chips pushing away the fluid lines can be tough.
• -  Chips can get stuck in adapters that have grooves, cutting or deforming the part or creating bird nests.
• -  Roughing tools can work harden the material and destroy the finish tools.