The Development of CNC Machine Tools Breaks through the Bottleneck of Aviation Manufacturing

Aviation manufacturing requires advanced, integrated, flexible, high-precision, and high-stability CNC machine tools. The CNC system is the core of CNC machine tools and the brain of CNC machine tools.

The faster and more powerful CNC system allows CNC machine tools to have more powerful computing and processing capabilities, enabling more sophisticated and sophisticated machining. The composite function makes the CNC machine tool significantly improve the machining efficiency of the part. The machining process tends to be high-precision, multi-variety, small-batch, low-cost, short-cycle and complicated processing. With the increasing use of numerically-controlled machine tools in the production of aerospace parts, the processing capability of aerospace parts has been significantly improved. The complex part-profile surface can be completed using digital processing, and its use of ordinary equipment is difficult to process. of.

Although the processing capability of parts has been improved, the application level of CNC machine tools has yet to be improved. No matter programming technology or processing technology, there is still room for improvement. The development of advanced functions of CNC machine tools, improvement of the machining efficiency of CNC machine tools, and the maximization of the superiority of CNC machine tools have become the biggest problems faced by technical personnel.

1. CNC machine tool function development content

The development of aerospace manufacturing CNC machine tools includes the following aspects:

(1) Develop the hardware functions of CNC machine tools, such as the development of drill breakage detection functions, the tool length and radius under machining conditions, and the development of automatic measurement functions in the machine. This kind of function development is aimed at the fact that some CNC machine tools have not been equipped with on-line measurement devices and other hardware facilities in the introduction. It is the introduction of advanced equipment into the production process, thereby improving the advanced nature of the production process.

(2) Introduce the advanced instructions of the operating system into the production process, and further develop the advanced nature of CNC machining. Develop advanced instructions for machine tool operating systems, such as programmable zero offset, programmable rotation (multi-face machining), etc.

(3) The secondary development of high-level programming languages ​​can greatly improve the advanced nature of CNC machining.

Use advanced commands to compile template programs with specific functions, do regular calculations, detect and judge machine data, and then simplify or optimize the machining process or increase the error-proof function in the machining process. The program can more specifically solve the problems encountered in the production of parts.

2. Typical problems of CNC machine tools

In the application of CNC machine tools, there are often problems of low programming efficiency and processing efficiency, and the process is easy to make mistakes. The following are representative examples:

(1) CNC milling CNC programming needs to calculate more parameters, the programming process is relatively complex and error-prone, so the programming milling thread program is low in efficiency and error rate.

(2) For parts with evenly spaced holes or evenly grooved, each hole must be processed with repeated NC programs. When the machining part has a large margin, it is necessary to repeatedly call different tool compensation values ​​of the same NC program to remove the excess. .

This kind of large amount of programming work, a large amount of work, low programming efficiency. Repeated knife work is heavy and prone to errors.

(3) Due to the limitation of the travel of some CNC machine axes, the cycle mode cannot be used when programming, and only the point coordinates can be programmed. The programming efficiency is low and error-prone.

(4) If the tool is damaged during processing, if it is not found in time, it is likely to cause scrapping of the parts.

(5) When machining a part using contour programming, the operator needs to input the tool radius in the machine tool. The input radius is different, and the cutting path of the tool is also different. Entering the wrong tool radius can easily lead to poor parts.

(6) Before CNC machining of parts, it is necessary to establish a machining coordinate system. The operator needs to input the origin of each coordinate axis into the machine tool, and the operator is likely to make mistakes when inputting parameters.

3. Comprehensive development of CNC machine tools

(1) Anti-error function development. Through the operator to check, to prevent mistakes, the main body of this type of mistake-proof method is the person. The effect of error prevention in the actual operation process is directly related to the person's ability and attention and can not achieve 100% error prevention. The use of special technical means to control the operation process, the computer to check, meet the conditions are processed, will not meet the conditions to stop, can basically achieve 100% error prevention. Specifically include:

1Drill damage detection function development. Can effectively detect tool wear in the process of machining, the tool will be alarmed after damage, to avoid damage to the tool to continue machining the parts caused by the excess parts.

2 Vertical lathes and horizontal lathes The development of tool centering and anti-error functions shall be established respectively. The tool inspection template shall be established respectively. Before the machining, the tool checking point shall be checked. If the operator does not modify the tool setting point, the program will be aborted and can be effectively avoided. Parts are poor.

3 knife compensation mistakes. Create a tool radius inspection template, check the radius of the tool before machining, if the input radius does not meet the requirements, the program will be suspended, which can effectively avoid the parts out of tolerance.

4G54 anti-error function for milling and development of CNC machine tool G54 error protection. These two sub-programs respectively establish the coordinate system detection, call the detection subroutine before the program runs, if the coordinate system is wrong, then the program is suspended, which can effectively avoid parts out of tolerance.

(2) Comprehensive development of the functions of CNC machine tools to achieve "unmanned intervention in the whole process". "Process-free intervention" processing means that the processed workpiece is installed on a numerically-controlled machine tool and a process starts to complete the processing and inspection process without manual intervention. It transforms the traditional processing form in which product quality and processing efficiency depend on the skill level of the past into a new form that is guaranteed by the whole process, uninterrupted processing control, and equipment functions, and ultimately achieves high efficiency, precision, full program, and unattended intervention. Processing.

Specifically include:

1 Curing tool holders and tools, optimizing cutting parameters, and achieving accurate statistics on tool life; optimizing the machining process based on the need for uninterrupted CNC machining, adding measurement programs, reducing repetitive machining, and programming the original program as a subroutine. In the machining process program, the “automatic tool setting”, “measurement pause” and “hint instruction” are also fixed in the process monitoring NC program. In the monitoring program, the coordinate system frame instruction and the tool parameter advanced instruction are used to realize the processing. The whole process of monitoring and management.

2 through the tool radius compensation, tool length compensation and coordinate origin monitoring, eliminating the operator's human error in the data entry process, while using information prompts to make the operation more concise and easy to understand, more effectively reduce the operator participation rate.

3 coordinate origin error prevention, judgement by absolute coordinate and adjustment of coordinate value, and alarm when over range, eliminate operator's misoperation in origin setting process.

4 Optimize the cutting amount; According to the need of uninterrupted CNC machining, optimize the processing flow, reduce the repetitive processing, and compile the original program as a subroutine in the process flow program.

5 Increase the automatic tool setting command to replace the previous manual tool setting operation. At the same time, all the machining programs are connected in series and the processing parameters are solidified so that the whole process can be automatically completed. The whole process achieved no intervention or less intervention.

6 CNC lathes online measurement technology function development. On-line inspection can significantly improve the processing efficiency, avoid the secondary clamping positioning caused by offline inspection and repair, and ensure the processing quality. Real-time correction and compensation can be performed on the parts being processed to eliminate the production of waste defective products. Expand the functions of CNC machine tools, improve the performance of CNC machine tools, and increase the efficiency of CNC machine tools. Automatic research on the turning process, automatic tool correction technology and tool automatic compensation technology are carried out in-depth research, which can be automated to complete certain processing, measurement and tool compensation, improve part machining efficiency and utilization of CNC machine tools.

(3) Development of machine tool composite functions to improve the level of intelligent machine tools. Machine tool manufacturers should develop machine tool composite functions to significantly increase the level of machine tool intelligence. The realization of the composite functions of CNC machine tools relies on real-time detection and intelligent judgment, data calculation, tool management and system control for workpieces and tools. High-sensitivity probes, high-speed processing chips, and automated products and technologies such as smaller-size, faster-response sensors and actuators will be widely used. After the CNC machine tool is programmed, the machine tool is executed according to the commands provided by the program. During the machining process, the machine tool can monitor whether the tool is worn or not, whether the spindle has heat, vibration, etc., and can interrupt the machining process at any time, change the operating parameters, and reduce Speed, reduce the feed rate, protect the machine or stop running. The machine tool manufacturer should specify the development trend of CNC machine tools, grasp the development direction of CNC machine tools, and make the functions of CNC machine tools complex and intelligent to meet the needs of customers.