Over the past several years titanium alloys have become a popular choice for structural and other parts for the aerospace and other industries. However working with titanium is challenging due to its physical characteristics and chemical composition. For example, titanium is a poor conductor of heat and more heat is generated when machining titanium than many other metals.
According to cutting tool maker Sandvik Coromant, this exposure of the cutting edge to higher temperatures along with high-pressure cutting may cause premature tool wear. Plus, titanium has a tendency to smear during machining, and this can cause chips to weld to the insert, thus causing edge line problems when re-entering the cut. There’s also an increased risk of chattering caused by titanium’s elasticity.
To deal with these problems, follow these general guidelines when machining titanium:
- Use relatively low cutting speeds
- Use sharp cutting edges
- Optimize feed rates and avoid idling while in cut
- Use large volumes of coolant, preferably at high pressure through spindle and tool
- Replace cutting edges at first sign of any wear
- Employ climb (down) milling wherever possible
- Consider all aspects of the machining process including tooling, fixtures, machine spindle rigidity and speed, and the CNC machine’s control system.
Of course the heart of the process is the CNC machine, itself. That’s why it’s important to have equipment with a rigid spindle and tool holder to eliminate the vibrations that cause out-of-tolerance parts. It’s also critical to maintain a constant cutting feed rate, because if the spindle starts to slow down, the tool may burn up. Additionally, the machine’s control must be capable of maintaining consistent acceleration and deceleration.
Your Torrance, CA Haas Factory Outlet consultants are ready to answer your machining questions and demonstrate how the new ST generation of Haas CNC lathes and turning centers are designed to meet your toughest challenges. To learn more call (310) 381-0750, email: jphillips@haasfactoryoutlet.com, or visit www.haasfactoryoutlet.com.