Machining Composite Materials
July 17, 2012
As with all hard-to-machine materials, nickel-based alloys present some significant challenges that can impact productivity, so it’s important to know what you’re up against.
One critical issue is that there are a number of different nickel-based alloys available, each with unique characteristics. Some are predominantly nickel, have the least hardness and tend to become very gummy when machined. Others, such as nickel-copper and nickel-iron have higher strengths and are typically cold-drawn as they cannot be hardened through heat-treating. There are also some alloys that include titanium or aluminum, which adds another degree of cutting difficulty. So the first step is to identify the type of nickel-alloy you are machining so that you can select the appropriate cutting tool, CNC machine type and program scheme.
In general, nickel-based alloys tend to become work hardened during the cutting process. This means that the metal around the cutting tool can become much more difficult to machine as the process continues. So, again, selecting a cutting tool with the right geometry, hardness, coating and sharpness is critical.
Although using the right cutting tool for the specific alloy is vitally important, the capabilities of the CNC machine tool are equally significant. It’s essential to use a machine with a rigid spindle and tool holder that will eliminate the vibrations that contribute to out-of-tolerance parts. Maintaining constant spindle speed is also vitally important. If the spindle starts to slow down the nickel-based alloys will work-harden and make the next pass more difficult. In the same way, the machine’s control must be capable of maintaining consistent acceleration and deceleration, and to quickly process data so it can prevent dwelling or reduced spindle speeds. Finally, the CNC machine must have the amount of consistent power necessary maintain optimum speed and feed rates.
The applications experts at Gosiger work with customers to help them make the right choices in CNC machines, cutting tools and programming for many difficult-to machine materials. Bring your most challenging application to Gosiger today.