Machining Solutions-HRSA
Information provided by
Global Industry Project Manager - Aerospace, Power Generation and Medical
Ni-Based Super Alloys have high tensile strength which results in extreme cutting forces at the tool edge during machining. These alloys also have low thermal conductivity which transfers the heat generated during machining back into the tool, which consequently raises the tool’s temperature and causes excessive tool wear.
Some of the alloys also have the tendency to work harden, which can cause problems for tools in areas where the tool may dwell or need to be used to take a light depth of cut. While machining, a depth-of-cut notch may occur in the cutting tool creating surface finish problems, cause burrs to form in the work piece, and can lead to edge fracture of the tool itself. Finishing is critical to aerospace components, as the quality of the machined surface can affect the useful life of the part due to the microstructure of the workpiece material being affected. After final finishing, close attention is required to avoid damage to the machined surfaces due to handling or shipping of the parts.
The machining solutions for Super Alloy
First, a common solution to address heat when machining super alloy is the use of high-pressure coolant to mitigate heat as it is generated. Cutting edge heat is one of the biggest challenges when machining Super Alloys, so proper coolant supply is important. If the tool has an internal coolant supply or coolant nozzle and is directed close to the cutting edge using a high-pressure coolant pump of at least 70 bar(1000PSI), a much higher level of machinability can be achieved.
Another approach as an alternative method for heat mitigation is the use of cryogenics. While this method has been available for some time, cryogenics comes with a very high cost of entry. Updating the typical milling machine with cryogenics can cost as much as USD 60,000, so this is a process that shop owners do not arbitrarily adopt.
Second, proper feed rate and cutting depth should be maintained to minimize work hardening, and tools should not be allowed to dwell on the part surface to minimize the possibility of problems in subsequent processes. For semi-finishing and finishing, a tool with a positive rake applied with high heat-resistance PVD coating is suitable.
YG-1 tools for machining Super Alloy
YG-1 has developed tools suitable for machining super alloys such as Inconel.
'TitaNox Power HPC’ is a solid carbide End mill recommended for high-performance milling of Heat-Resistant Super Alloy, Stainless Steel, and Titanium. This new 5 flute design is specialized for heavy cutting using a double taper core and is designed for superior chip evacuation and strength. It’s excellent for Heavy Profiling and high-speed machining techniques.
Our new solid carbide drill for Super Alloys, YG-1 recommends our ‘Dream drills Super Alloy’ with 2 flutes using a unique Flute Shape, Carbide Grade, and optimized PVD Coating for Super Alloys.
YG401 Grade is a PVD coated turning grade optimized for Heat Resistant Super Alloy machining. YG401 grade with 3 different chip breakers that are designed to be free cutting with high edge security, our SF, SM and SR geometries perform well in finishing to roughing operations on HRSA materials.