Precision machining in the field of aviation

Precision machining technology is an indispensable key technology in the aerospace, aerospace and electronics industries, and military industry.

As the forefront of high-tech fields, aviation has more prominent requirements and reliability for precision machining, mainly due to the increasing dimensional accuracy and surface quality requirements of parts. China must break through key core technologies such as aircraft engines, airborne equipment and materials. The processing of typical and difficult-to-machine materials is a key link.

Machine processing

There are three types of aircraft engine casings, one is a split ring structure, the other is a monolithic ring structure, and the other is a profiled casing. The casing material is a high-temperature resistant titanium alloy material that is difficult to process. The casing is also a thin-walled, weakly rigid structure with complex profiles, high precision requirements and high processing difficulty. The casing is a large part, and the thrust of a 15,000 kg aero engine is Ф800mm. The large fan size of the large aircraft is 1823.5mm × 546mm, and the thinnest part is 3mm thick. Therefore, machine processing requires medium and large-scale multi-function, high-precision CNC machine tools. For example, a CNC vertical car and a precision CNC vertical car with a diameter of Ф2000mm; a gantry-type five-axis linkage machining center with a working table size of 2400mm×5000mm, with dual-station, on-line measurement and simulation functions, with a tool magazine capacity of about 60 knives. The CNC system has advanced programming capabilities. The machine tool positioning accuracy X/Y/Z is 8μm/8μm/5μm respectively. When the machine is running at high speed, the spindle speed is above 10000r/min, the spindle power is 15 kW~30 kW, with rotary table, positioning accuracy ≦8; table 3000mm× 5000mm gantry key milling machine with rotary table, spindle speed 6000r/min.

Blade processing

The blade material of the aero-engine is a high-temperature resistant titanium alloy material, which requires a five-axis linkage machining center and a five-axis high-speed gantry milling machine to process the blade surface. The processing of the root root caries requires a broaching machine and a slow-feeding to the powerful grinding machine, and it is hoped that the powerful grinding machine has the function of changing the grinding wheel and the wheel dressing wheel device, and also needs online measurement, program adjustment and automatic compensation.

Electrolytic processing of the blade surface can greatly improve the processing efficiency, and it needs to be polished by a numerical control six-axis belt polishing device. It is desirable to have a blade surface inspection device.

Large wide-chord hollow fan blades with wide chord, hollow and damped boss structure, diameter less than 1600mm, fan tip speed of up to 457m / s, using lighter weight titanium alloy or resin-based materials, the manufacture of such blades requires 1000mm ×400mm×570mm five-axis blade milling machine; automatic polishing machine with precision of 0.025mm; combined sealing and diffusion bonding and superplastic forming equipment.

The blade has a lot of holes for cooling, and it is better to punch holes with electric pulses than to use laser drilling (laser drilling has a hardened layer), but now, the electromachining punching machine does not have a shallow hole display, and the operation is difficult. I hope to solve this problem and show the depth of the punch. The nickel-based single crystal turbine blade with high temperature resistance of 1100 °C has good high temperature strength and comprehensive performance. There are many cooling film holes with diameters of Φ0.3mm~Φ0.4mm on the blade. A crystal melting furnace, a ceramic core roasting furnace, a core making machine, a grinding center, a numerically controlled jog grinding machine, and an electro-hydraulic beam current device and a small hole processing unit for the blade hole making.

Whole leaf disc processing

The integral leaf disc is a thin-walled disc type with a bladed groove on the circumference of the leaf disc. Straight grooves can be processed by broaching and grinding. The circular arc-shaped bevel groove can be machined by milling and forming, but the detection of the arc-shaped bevel groove is difficult. The processing of the leaf ring and the leaf disc requires a CNC sleeper and a precision CNC vertical car. The processing machine tool is required to have good rigidity and high positioning accuracy, and the positioning accuracy is about 2 μm to 3 μm. The blade portion of the integral leaf disc can be processed by a five-axis high-speed machining center, and can also be processed by EDM. The diameter of heavy-duty gas turbine blades can reach 2000mm-3000mm, which requires high-speed grinding machine with a grinding wheel speed of l00m/s or more.

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