1. Characteristics analysis of CNC bending machines
There are many waveguides in press brake operation. The quality of waveguide curvature processing directly affects the performance of the radar system.
In traditional bending processing, the main processing methods used are groove type, rigid core rod type, flexible core rod type and internal filling type.
However, these methods have low work efficiency, produce few finished products and present processing difficulties during use.
Therefore, in the application of waveguide bending technology, it is necessary to reasonably use curved waveguides instead of traditional welding parts to simplify the overall process, reduce production costs, and improve the reliability and effectiveness of equipment processing.
1.1 Analysis of Necessary Technical Indicators
Firstly, bending processing needs to be carried out in the E and H planes, with the bending angle controlled between 30° to 150°, and the accuracy should be within ±1.6°.
Secondly, the minimum curvature radius of the E-plane needs to be about 21 mm, while that of the H-plane needs to be about 41 mm.
Finally, the deformation of the internal cavity also needs to strictly control the cross-sectional size within 0.05mm and meet the electrical performance requirements.
1.2 Characteristic Analysis
During the bending process of waveguides, not only will there be changes in the cross-sectional shape, but also changes in the wall thickness.
Therefore, it is necessary to focus on the situation of the internal cavity size during the bending process and understand the specific amount of change.
During the pipe bending process, it is necessary to understand the compression deformation of the inner part and clarify the thickness and width characteristics.
As for the tensile deformation of the outer surface, it mainly manifests itself in the increase or decrease of the wall thickness, and the width of the side surface will also determine the actual characteristics of the waveguide.
1.3 Analysis of the bending stress-strain situation
For waveguides, compared with round tubes, rectangular tubes are not self-supporting structures, and the fluidity of the internal and external arc lines of the circular metal during bending cannot be guaranteed.
Therefore, it is difficult to form a small-radius curvature state in the actual analysis of rectangular tubes.
Generally, in practical work, it can be assumed that the same deformation resistance force will be generated for metal materials under tension and compression, and the mechanical properties of the metal can be expressed uniformly, thus forming the same tension and compression method.
During the actual analysis of the waveguide mold and central rod, it can be considered as a rigid structure and the geometric size of the inner cavity of the tube will not change. Only stress-strain analysis of the tube wall needs to be performed.
At the beginning of the bending process, a coincidence phenomenon occurs between the neutral material and the tube material.
After increasing the deformation, the neutral material will partially move, and the tensile area gradually increases while the compression structure decreases, and the wall thickness on the outer side shows an obvious thinning tendency.
When processing waveguides with softening characteristics, elastic deformation problems can be ignored. If the value of R/B is very small, then the amount of deformation will be large, and the material will be in a plastic state, and the pipe will also be subject to certain axial stresses.
Before and after bending, if the position of the neutral layer can be kept unchanged, Y can be used as the main coordinate point, and the formula AY = AS + gb can be used, where G = Y/B represents the stress condition of the fiber layer.
In the process of assuming the section, if it is in the ideal state, the stress distribution of the cross section can be expressed by Figure 1.
Assuming that the bending angle of the tube in actual processing is A, and the neutral layer coincides with the tube, the tension length of the neutral layer can be expressed by the formula L = RA.
In the actual material calculation, the length of the outermost layer can be expressed by the formula L = (R + B/2)A, and for the inner material of the bent tube, the length is l = (R – B /2)A .
2. Design Measurements for Automatic Waveguide Bending
2.1 Analysis of Specific Technical Methods for Design Work
Specific technical methods for design work are as follows:
① In bending design work, it is necessary to fully understand the mechanism and carry out reasonable tension tests to comprehensively understand the characteristics and deformation conditions of the material;
② Repeated experiments are conducted to analyze the bending deformation data information of waveguides under various conditions and obtain accurate tensile limit parameters;
③ Develop a perfect bending heat treatment plan, clarify the content of various aspects of the work standards, so that the bending force and main thrust force of the waveguide during bending meet the regulations;
④ Reasonably rotate the material and shape of the core rod during bending;
⑤ Carry out the electronic control machine design reasonably in accordance with the relevant bending angle accuracy standards;
⑥ During the actual design, it is necessary to reasonably produce the mechanical properties of the waveguide.
2.2 Clarification of the Composition of the Bending Machine System
In the actual operation of automatic waveguide bending machines, the main structural components are clamping system, loading and unloading system, axial thrust system, main rotation system, control and power system, etc.
During the operation of the loading machine, the clamping system can cooperate to reasonably install and fix the core rod material.
For the control system, it mainly controls the camber angle comprehensively. The hydraulic cylinder drives the rack to achieve scientific bending processing, comprehensively improve the overall processing level, and meet current development needs.
For the clamping system, it is mainly designed with a crank connecting rod method in actual operation, which can form a high clamping force under a small rotating driving force to strengthen the control of the clamping state of the mold during forming.
For loading and unloading machines, a double L-type split combination method can be used to rationally design the cavity structure according to relevant bending characteristics.
In the design work, rigorous discussion and analysis of the rectangular cavity must be carried out, which must be divided diagonally. If the machine is on the clamping output turntable, the tube will automatically separate from the mold to complete the unloading task.
During the actual operation of the axial thrust system, the thrust size is adjusted based on the information from the bending radius data in the waveguide bending work, reducing the current problems.
During pressure adjustment, thrust reliability and effectiveness can be improved to increase the effectiveness of loading and unloading the center rods.
During the actual operation of the main rotation system, a rack system is mainly used to rotate under the drive of the hydraulic cylinder, comprehensively improving the driving force, increasing the compactness of the structure, improving the stability of system operation, and improving the uniform rotation speed to avoid impact effects.
During the actual operation of the automatic control system, electromechanical integration control technology is mainly used to fully utilize the positive role of programming controllers, achieve the purpose of mechanical coordination and management, and use a rotary encoder to reasonably measure and feedback the bending angle to improve the overall working level.
3. Conclusion
The use of automatic waveguide tube bending machines can reform traditional bending processing methods. In addition to shortening the overall production cycle, it can also reduce production costs and improve the economic benefits of bending processing.
After investigation, it is found that the processing cycle can be reduced by about 90%, the production cost can be reduced by about 95%, and the yield rate is about 95%.
