Application and optimization of NC multi-axis machining in aviation manufacturing

Application and optimization of NC multi-axis machining in aviation manufacturing

The emergence of CNC multi-axis machining technology can be traced back to the development of CNC technology and multi-axis machine tools in the 20th century. With the continuous progress of computer technology, the numerical control system is becoming more and more powerful, and the accuracy and stability of multi-axis machine tools have also been greatly improved. The continuous evolution of this technology provides more opportunities for innovation in the field of aerospace manufacturing. Aerospace manufacturing is a highly sophisticated and safety-demanding industry, and the introduction of any process technology must undergo rigorous evaluation. The application of CNC multi-axis machining technology is important to aviation manufacturing because it can improve the precision, complexity and production efficiency of parts. In this field, the manufacturing of aviation parts often requires highly precise machining, and CNC multi-axis machining technology can achieve higher machining accuracy and greatly reduce the interference of human factors.

1 Overview of CNC multi-axis machining technology

1.1 Basic principle of CNC multi-axis machining technology

The basic principle of CNC multi-axis machining technology can be summarized as the precise control of multiple axes at the same time to achieve high-precision machining of complex workpieces. Among them, the key components include numerical control systems, multi-axis machine tools and tools. The CNC system is the brain of the entire machining process, which accepts the CNC program written by the engineer and converts it into the instructions for the axis movement, which usually includes parameters such as the speed of the axis movement, the direction and the depth of the cut. Multi-axis machine tool is the actual processing executor, it can control the movement of multiple axes at the same time. Different machine types can achieve different types of movement, such as rotation, translation, tilt, etc., and the coordination of this multi-axis movement is the key to achieve high-precision machining. Tool selection and use is also an important part of CNC multi-axis machining, tool type, size and material will affect the efficiency and quality of processing.

1.2 Different types of multi-axis machine tools and their applications in aerospace manufacturing

(1) Five-axis CNC milling machine. Five-axis CNC milling machine is a machine tool that can simultaneously control the movement of tools and workpieces in five axes. In general, it consists of three linear axes, X, Y, and Z, and two rotational axes, A and C. This structure allows the five-axis machine to rotate and move in a complex manner, thus achieving multi-angle, multi-direction cutting operations. Five-axis CNC milling machine is widely used in aviation manufacturing. They can process aerospace components with complex curved surfaces and multi-angle characteristics, such as turbine blades, combustion chamber parts and fuselage components. These components often require high precision and surface quality, and the flexibility of five-axis machines allows them to meet these requirements.

(2) Six-axis CNC robot. Six-axis CNC robots have six rotating axes and are usually used to handle workpieces in three-dimensional space. They can perform complex movements such as bending, rotating, and tilting. In aerospace manufacturing, six-axis CNC robots are often used to automate assembly line and welding work. They enable accurate positioning and installation of aerospace components while improving production efficiency and quality consistency. For example, in aircraft assembly, six-axis robots can be used to install components such as wings, tail fins and aircraft shells.

(3) Multi-axis CNC lathes. Multi-axis CNC lathes have multiple rotating axes and linear axes, and are usually used to process rotationally symmetrical workpieces. They enable complex cutting operations such as threading and gear machining. In aerospace manufacturing, multi-axis CNC lathes are commonly used for machining engine components such as turboshafts and turbine blades. These parts have rotational symmetry, so multi-spindle lathes can perform machining tasks efficiently. In addition, multi-spindle lathes are also used to process aircraft landing gear parts and connecting rods.

(4) Seven-axis CNC machine tools. The seven-axis CNC machine adds two linear axes to the five-axis CNC milling machine, providing greater range of motion and flexibility. Seven-axis CNC machine tools are often used in aerospace manufacturing to process complex workpieces, such as compressor blades for aircraft engines. These blades have complex spatial curves, and seven-axis machines enable high-precision machining in a freer manner.

2 Application of CNC multi-axis machining in aviation manufacturing

2.1 Case 1: Turbine blade manufacturing

An aerospace manufacturing company uses a five-axis CNC milling machine to make turbine blades, one of the key components in an aircraft engine. The five-axis CNC milling machine is a highly flexible machining device with the ability to control the movement of tools and workpieces in five axes at the same time. This machine enables complex cutting operations and is suitable for machining workpieces with complex curved surfaces and multi-angle features, such as turbine blades. Mathematical modeling is a critical first step in turbine blade manufacturing. Engineers use computer-aided design (CAD) software and mathematical modeling techniques to create an accurate three-dimensional model of a turbine blade that includes the complex geometry of the blade, the airflow channels, and the surface details. Through mathematical modeling, each dimension and curvature of the blade can be precisely defined, providing an accurate reference for subsequent processing. Once a mathematical model of the blade is available, tool path planning becomes a crucial step. Dedicated tool path planning software is used to determine the path of the tool to minimize machining time while ensuring high precision machining. Path planning requires precise control of the tool's movement to ensure that the cutting is stable and accurate, which includes the optimization of parameters such as the start and end of the cutting, the cutting direction, the cutting depth and the cutting speed. High-speed cutting technology has been widely used in turbine blade manufacturing to improve production efficiency and ensure surface quality. High-speed cutting uses high-speed rotating tools and fast cutting motion to reduce processing time, while also helping to reduce the cutting temperature and reduce the heat-affected area, thereby improving surface quality. High-speed cutting also reduces the cutting force, prolongs the tool life, and reduces the cutting vibration, further improving the machining accuracy.

2.2 Case 2: Aircraft fuselage component manufacturing

A seven-axis CNC machine tool is a highly flexible machining device with seven independently controlled axes of motion, including rotary and linear axes. This machine tool can realize complex workpiece processing and multi-axis collaboration, and is suitable for machining aircraft fuselage components. At the same time, the automation system is used for automatic assembly process to improve production efficiency. In this case, an aerospace manufacturing company used a seven-axis CNC machine tool and automation system to manufacture aircraft fuselage components. Robot programming is one of the key steps in automated manufacturing. Engineers use specialized robot programming techniques to write motion trajectories and operating procedures for seven-axis CNC machines and automation systems, which determine how precisely the machines and robots are controlled during machining and assembly. In the programming process, the geometry, size and characteristics of different components need to be considered to ensure that the robot can be accurately positioned and operated, and accurate programming ensures the consistency and accuracy of the processing and assembly of components. Multi-axis collaboration technology is the key to realize complex machining and assembly, which allows the cooperative movement between different axes to realize the machining and assembly of complex components. In fuselage component manufacturing, different parts may need to be moved, rotated, or tilted at the same time in order to fit them together precisely. Multi-axis collaboration requires fine coordination and motion control to ensure that each part of the component is accurately aligned during the assembly process, which improves the accuracy and efficiency of the assembly. The automatic assembly system is used for the automatic assembly of aircraft fuselage components. Engineers write automated assembly programs that specify the correct position, orientation, and assembly sequence of individual parts. Automated assembly systems can perform a variety of tasks, including picking, positioning, rotating and securing parts. Through automated assembly, human intervention can be reduced, and consistency and assembly efficiency can be improved. This is essential to ensure the quality of the assembly of aircraft fuselage components, as they are directly related to the safety and performance of the aircraft.

2.3 Case 3: Aircraft landing gear parts processing

How an aerospace parts manufacturing company applies multi-axis CNC lathe technology and related methods to process aircraft landing gear parts. A multi-axis CNC lathe is a highly flexible machining device with multiple independently controlled axes of motion, including rotary and linear axes. This machine tool can realize complex workpiece processing and is suitable for machining aircraft landing gear parts. At the same time, tool optimization technology is used to improve cutting efficiency and reduce cutting costs. In this case, CAD/CAM integration technology is the key to the machining of aircraft landing gear parts. Engineers use CAD (computer-aided design) software to create three-dimensional models of parts and subsequently seamlessly translate these models into numerical control programs (CAM), which ensures precision and consistency in machining while saving time. The CAM program includes parameters such as cutting path, tool path, cutting speed and feed speed, which are generated from the CAD model to ensure that the geometry and dimensions of the parts are consistent with the design. Optimization of cutting parameters is the key to ensure efficient machining. This process includes the optimization of parameters such as tool selection, cutting speed, feed speed, cutting depth and cutting coolant use. The optimization of cutting parameters can improve machining efficiency and reduce material waste, while also helping to reduce the cutting temperature and reduce the heat-affected area, thereby improving the surface quality.

3. Optimize the method of CNC multi-axis machining

3.1 Importance of parameter adjustment

(1) Optimization of cutting speed. Properly increasing the cutting speed can significantly improve production efficiency, and high-speed cutting technology is able to remove more material in the same amount of time, thereby reducing processing cycles and increasing the yield of parts. The optimization of the cutting speed can help reduce the cutting temperature. High-speed cutting is usually accompanied by faster tool movement and smaller cutting times, helping to reduce the size of the heat-affected area, which is critical to avoid thermal deformation, improve surface quality and reduce residual stress. By choosing the right cutting speed, the wear rate of the tool can be reduced and the service life of the tool can be extended. This reduces the frequency of tool changes and reduces downtime in production.

(2) Optimization of feed speed. Appropriate feed speed can reduce the vibration between the tool and the workpiece, improve the stability of the processing, the reduction of resonance phenomenon can reduce the instability of the cutting force, help to maintain consistent processing quality. By selecting the appropriate feed speed, the jump between the cutting paths can be reduced, and the surface defects and roughness can be reduced, which helps to improve the surface finish of the parts and meet the high-quality surface requirements. The optimization of feed speed can reduce cutting forces, reduce tool and machine wear, and increase the life of tools and equipment, which is key to reducing production costs and improving equipment reliability.

3.2 Key steps of process optimization

(1) Tool path planning. By choosing the shortest tool path, processing time can be reduced and production efficiency can be improved. In aerospace manufacturing, complex workpieces often need to be machined, so reducing processing time is key to meeting production cycle requirements. Tool path planning can also affect cutting forces and vibrations during cutting. By optimizing the path, you can reduce the impact and vibration between the tool and the workpiece, reduce the cutting force, extend the tool life, and improve the stability of the machining. In tool path planning, it is necessary to avoid interference between the tool and the clamping device. Interference can lead to machining interruption and workpiece damage, so proper path planning is essential to ensure the stability and safety of the processing.

(2) Optimization of cutting strategy. The cutting strategy includes the decision of cutting depth, cutting width, cutting speed and feed speed. By selecting the appropriate cutting depth and cutting width, maximum material removal can be achieved, resulting in increased production efficiency. In aerospace manufacturing, high material removal rates are often one of the key objectives, as it reduces processing cycles. An appropriate cutting strategy can help reduce the heat accumulation during cutting and reduce the processing temperature. This is important to avoid thermal deformation, improve surface quality and reduce residual stress. Through the optimized cutting strategy, the tool wear can be reduced, the surface quality can be improved, and the requirements of high-quality surface can be met. This is critical for components in aerospace manufacturing, as surface quality directly affects performance and safety.

(3) Tool selection. The choice of the tool is crucial to the processing efficiency and part quality, and the appropriate tool should be selected according to the processing task and the workpiece material. Different workpiece materials require different kinds of tools. For example, cemented carbide tools are suitable for machining high-strength materials, while coated tools can improve cutting performance. Cutting conditions such as cutting speed, cutting depth and feed speed also affect the selection of the tool, and the appropriate tool should be adapted to the specific cutting conditions to achieve the best processing results. The geometry and complexity of the workpiece can also affect tool selection. Different tool geometers are suitable for different types of machining, for example, ball-head tools are suitable for machining curved surfaces.

3.3 Data-driven optimization method

(1) Application of artificial intelligence in tool life prediction. Artificial intelligence can predict the life of a tool by collecting and analyzing a large amount of cutting data, including tool wear, machining parameters and workpiece materials. This data can be acquired in real time through sensors and monitoring systems, and then processed and analyzed by machine learning algorithms. Based on the collected data, AI can build a tool life prediction model that predicts when a tool will need to be replaced or maintained, which can help reduce unplanned downtime and increase productivity. Once a life prediction model is established, AI can automatically make decisions on how to adjust cutting parameters and when to replace tools to maximize tool life. This reduces human intervention and improves processing stability.

(2) Application of machine learning in cutting parameter optimization. Machine learning algorithms can analyze a large number of machining data, including machining effect and part quality data under different cutting parameter combinations, by learning these data, machine learning can find the best cutting parameter combination, so as to achieve automatic cutting parameter optimization. Machine learning can also adjust cutting parameters in real time to respond to changes in machining.

(3) Data-driven quality control. The data-driven approach allows real-time monitoring of key parameters during machining, such as cutting force, temperature and surface quality, and once anomalies are detected, the system can automatically adjust to ensure the quality of the parts. By analyzing machining and image data, a data-driven approach can detect defects and blemishes on parts, which can help identify problems in advance and take steps to fix them. The data-driven approach can also be used for process control to ensure that each process step is carried out within the specified parameters, which helps to improve the consistency and stability of the process.

4 Conclusion

The application of CNC multi-axis machining technology in aviation manufacturing has made remarkable achievements, providing key support for the production of high quality and complex parts. However, with the continuous development of the aviation industry, the requirements for processing technology are also constantly increasing. To meet these challenges, we need to continuously optimize parameters, process and tool selection for CNC multi-axis machining, and actively adopt data-driven approaches such as artificial intelligence and machine learning. The application of these technologies will bring a higher level of performance and efficiency to the aerospace manufacturing industry and drive the industry to a smarter and more innovative direction.

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