Application of the hottest digital automatic drill

Application of digital automatic drilling and riveting technology in aircraft manufacturing

with the development of cad/cam, computer information and networking technology, the digital design and manufacturing technology of aircraft products is mainly marked by the full adoption of digital product definition, digital pre assembly, product data management, concurrent engineering and virtual manufacturing technology, which has fundamentally changed the traditional aircraft design and manufacturing method, It has greatly improved the level of aircraft design and manufacturing technology. Automatic numerical control drilling and riveting technology is an important part of it

in aircraft manufacturing, the assembly connection quality directly affects the fatigue resistance and reliability of aircraft structures. High performance aircraft connection structures must adopt advanced connection technologies, such as advanced mechanical connection technology, advanced welding technology, bonding technology, etc. At present, foreign countries have used laser-assisted positioning, computer-aided optical theodolite, computer-aided drilling system and robotic assembly unit in assembly and connection technology, which has greatly improved the fatigue resistance of aircraft structure, reduced the number of operators and extended the service life of aircraft. Automatic drilling and riveting technology is the development direction of advanced connection technology

simulation of the automatic drilling and riveting assembly system of wing panels of e4320 automatic drilling and riveting machine

the requirements for the safe service life of modern aircraft are increasing. The service life of military aircraft and trunk aircraft are required to reach more than 8000 and 50000 flight hours respectively, and the load carried by the aircraft structure is transmitted through the connection parts, forming the stress concentration at the connection parts. According to statistics, 70% of the fatigue failure accidents of the aircraft body are from the structural connection parts, of which 80% of the fatigue cracks are from the connection holes. Therefore, the connection quality greatly affects the service life of the aircraft, and manual riveting is difficult to meet the service life requirements

the new ARJ21 branch line designed according to modern design standards and the wall panels and fuselage of large and medium-sized aircraft in the future manufactured by Xi'an airlines have higher requirements for fatigue resistance and reliability, and automatic drilling and riveting technology must be applied to achieve stable and high-quality connections. In the development of ARJ21 new branch line and large and medium-sized aircraft in the future, the wing development is the most difficult project, among which the automatic drilling and riveting of large wing panels is the key to the success or failure of wing development

the development of a full-automatic drilling and riveting system for large wing panels is an urgent need for the development of new aircraft in China. It is also one of the key technologies for the key breakthrough of avic-1, and it is also a challenge to catch up with and surpass the international advanced aviation manufacturing technology

research and application status at home and abroad

automatic drilling and riveting technology has been widely used abroad since the 1970s, and its development has been uninterrupted. At present, the automatic drilling and riveting rate of military and civil aircraft in production abroad has reached more than 17% and 75% respectively. Headless rivet interference fit technology is widely used. New fasteners include headless and crown rivets, titanium ring grooved nails, high locking bolts, conical bolts and various single-sided pull nails. 80% of riveting and 100% of non detachable shear bolt connections adopt interference fit, and the hole wall should be strengthened. The wall panel riveting system of Boeing civil aircraft has reached 60% - 75%, and that of McDonnell Douglas military aircraft has reached 17.5%, but the real automatic riveting still needs to solve the problem of workpiece positioning and leveling. In recent years, riveting is developing towards robots and flexible automatic assembly systems consisting of robot vision systems, large gantry robots, special flexible process equipment, fully automatic riveting machines and coordinate measuring machines. For example, B767 and B777 adopt the wing beam automatic assembly system, which improves the efficiency by 14 times, reduces the cost by 90%, and reduces the scrap rate by 50%. Further improvement can make the drilling and riveting tool reach the previously difficult parts

the main manufacturers of drilling and riveting machines are:

Gemcor company (General Electric Machinery Company) in the United States is the earliest manufacturer of automatic drilling and riveting machines, and it is also one of the main manufacturers providing automatic drilling and riveting machines to the aircraft manufacturing industry all over the world. The main models of automatic drilling and riveting machines produced by the company include G200, G300, g400, G900, g666, g39a, g4013, g4026 and g5013

assembly is the key link in the aircraft development process. At present, the workload of aircraft assembly in China accounts for about 30% - 45% of the total workload of aircraft manufacturing, and its assembly connection mode is mainly riveting. At present, aircraft assembly in China mainly depends on manual assembly, which has poor quality stability. A large number of complete sets of special assembly frames are used, which has high cost and low assembly efficiency. Assembly has become the bottleneck of aircraft development and production in China. Therefore, it is urgent to develop an automatic drilling and riveting system

in the past 20 years, nearly 10 automatic drilling and riveting equipment have been introduced in China, such as automatic drilling and riveting machines introduced by Xi'an airlines, Chengdu airlines and 625 Research Institute, and have been applied locally in subcontracting production. Some technical problems have occurred in production and application: such as deformation of bracket and riveting process, difficulty in ensuring workpiece positioning accuracy and riveting quality; The workpiece positioning clamping device interferes with the riveting process of the drilling and riveting machine; The automatic drilling and riveting system has poor stability of motion accuracy, and the repeated positioning accuracy is difficult to ensure

key technology of digital automatic drilling and riveting application

the core technology of automatic drilling and riveting system mainly includes: deformation analysis and error compensation technology, process simulation of automatic drilling and riveting system, large-scale high-precision control and assurance technology, flexible tooling technology, automatic drilling and riveting technology and equipment, etc

in 2003, the wing wall of ARJ21 aircraft of AVIC commercial aircraft Co., Ltd. 1. First of all, the displacement sensor board was checked, and the internationally advanced headless rivet connection technology was adopted. This technology was applied for the first time in the domestic aviation manufacturing industry. The connection form of headless rivets must adopt automatic drilling and riveting equipment to meet the design technical requirements and realize the stable and high-quality connection of wall panels. Under the condition of lack of data and foreign technology blockade, XAC restarted the research of automatic drilling and riveting technology. After several years of research, it has been able to complete the automatic riveting of wing panels of ARJ21 aircraft, and is developing the automatic riveting of fuselage and other large components

in the research on the application technology of automatic drilling and riveting, Xifei company has mainly solved the following key technologies

1 deformation analysis and error compensation technology of the bracket system of automatic drilling and riveting machine

if the digital controlled drilling and riveting machine is used for automatic drilling and riveting, an accurate image must be established between the computer theoretical model and the fixture and riveted workpiece. In order to establish such an accurate image, factors such as the self weight and load deformation of the bracket, the influence of the rotation of angle A and angle B on the deformation, and the offset to the theoretical coordinates must be considered. For deformation and coordinate offset, it is necessary to carry out real-time correction and compensation to make the computer theoretical model consistent with the fixture and riveted workpiece in the machine tool processing coordinate system

in order to achieve the purpose of engineering application, we must simplify the model, analyze and study its main influencing factors, establish a deformation model that can be used in engineering application, and then use the deformation model to correct and compensate the actual model. Through the structural analysis of the bracket and the measurement and analysis of different loads and different angle states of a and B, it is concluded that the deformation offset in the length direction of the bracket has little effect and can be ignored; The vertical deformation of the bracket has the greatest influence, which can be used as the main factor of deformation; The horizontal and horizontal deformation of the bracket also has an impact on the processing, which can be used as a secondary factor; The deformation model should be considered

the main data processing flow of automatic drilling and riveting machine is based on CATIA V5 platform. The main function of the deformation processing module is to combine the digital simulation and test data, build the deformation surface of the bracket in real time according to the algorithm, calculate the deformation and normal vector change of the rivet point, and modify the NC program in real time for riveting operation, so as to realize the preparation and deployment of digital riveting process, processing programming and automatic NC riveting on CATIA V5 platform

for this reason, we have developed the deformation processing program of the bracket of the automatic drilling and riveting machine for practical production by using the secondary development technology of CAA in V5, VBScript, Delphi, macro and other programming development tools

main design ideas and working process of deformation treatment of bracket of automatic drilling and riveting machine:

(1) establishment of deformation surface. According to the actual measurement or theoretical calculation data, the deformation model is established under CATIA V5

(2) merge deformation models. Copy the "deformation surface model" into the product model, rename the product model name to make it the current working model, merge it into the "deformation surface model/load deformation surface model", and change the Z value of the load deformation measurement point into the deformation value after the load according to the load deformation measurement table. Complete model merging and preprocessing

(3) use of deformation processing program. Open the deformation handler and select the one to process Aptsource file. Conduct deformation treatment

the program is a data processing software designed to meet the needs of the mathematical model of bracket deformation under the environment of CATIA V5, using the CAA secondary development technology of CATIA V5, VB, VBScript, Delphi, macro and other programming development tools

using digital manufacturing technology and g4026sxx-120 full-automatic drilling and riveting system, directly establish the workpiece digital model on CATIA V5 system, carry out rivet process distribution and processing programming. At present, the goal of full-automatic NC riveting has been achieved, and its position accuracy and normal accuracy meet the accuracy requirements of ARJ aircraft wing panel products (the maximum product rear panel length is close to 13m, which is a large workpiece with double curvature)

2 automatic drilling and riveting process design, process simulation and optimization

under CATIA V5 platform, there is no process layout and NC programming function specifically for drilling and riveting machines. To this end, we find out the most suitable functions for drilling and riveting process and programming in CATIA V5 system according to the situation of drilling and riveting machine and the numerical control function module of CATIA system, and realize the whole operation process of process, programming and tooling data processing on CATIA system platform

through the test pieces and the actual production application, it is found that due to the complex motion mechanism of the automatic drilling and riveting machine, interference and collision are likely to occur in the NC machining process. It is difficult for the programmer to discover in advance in the process design process. It is necessary to repeatedly test and adjust the program, and the adjustment strategy only depends on the engineering experience of the programmer, which is not intuitive, low efficiency, large errors, and the use efficiency of the equipment is greatly reduced. With the continuous expansion of the application field of automatic drilling and riveting machine, this contradiction will become more and more prominent. Therefore, it is urgent to use computer simulation technology to establish the motion simulation system of automatic drilling and riveting machine to solve the above problems

the motion simulation system of automatic drilling and riveting machine automatically completes the positioning, clamping, drilling/dimpling, gluing, nail feeding, riveting/installation of large wall panels in the assembly process, and ensures the positioning accuracy of the installed wall panels. The positioning accuracy of holes is an extremely complex process. Simulation of execution process based on the establishment of the motion simulation model of the whole system, simulate all the motion actuators of the system according to the riveting process scheme, and check the interference of riveting joints and clamping equipment in the riveting process and the collision in the system; Synthesis of flexible bracket and wall panel by dynamic simulation