For aircraft parts, the machining allowance may reach 80% of the weight, which means that the machining cycle is longer. Therefore, processing time is an evaluation parameter that we focus on. Roughing is primarily done to achieve maximum metal removal rates. Usually we adopt a solution that uses a large-diameter machine-cutter for roughing and reserves a certain amount of machining allowance for finishing. Since the processing at this stage accounts for a considerable amount of total processing time, it is necessary to optimize the operation to significantly shorten the processing cycle.
The remaining allowance is processed using a carbide end mill. The requirements mainly include good tool life, short machining time, high surface quality and high safety. To achieve these requirements, the following machining methods can be realized by arc cutting, small cutting width, multi-tooth, high cutting speed and large depth: corner piece milling, narrow groove cycloid milling, etc.
Cycloidal milling is an axial circular motion to achieve a controllable circular arc
In order to reduce the weight, the fuselage structural members often adopt a thin-walled structure. The thin wall is machined by means of a staggered tool path, that is, a small depth of cut is first processed on the thin wall side, and then the two sides of the thin wall are alternately machined at a normal depth of cut.
Solid carbide end mills are required for use on rigid machines with flexible operating systems. Use high-precision tool holder clamping to reduce runout (for every 100% increase in stroke, tool life is reduced by 50%). Coolant must be used to process titanium and superalloys (HRSA) to improve cutting control and limit cutting temperatures, and better performance if high pressure internal cooling is used.
Adopting arc walking, small cutting width, multi-tooth, high speed and large depth of cut,
This is the best way to achieve the finishing requirements with a solid carbide end mill
It is recommended to use such a solid carbide end mill: 50° helix angle, optimized design according to the number of teeth, positive sharp edge with positive rake angle, small support surface, rounded edge instead of chamfer and high performance Coating. In order to improve accessibility and reduce contact with the workpiece to reduce vibration, taper milling cutters are sometimes used.
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