1 Proposed issue
CNC electrolytic machining is a brand-new processing technology developed in the middle and late 80s. It introduces computer control technology based on the original copy electrolytic machining (cathode for linear feed motion), and increases the flexibility of cathode track control. Simplifies the cathode design and greatly shortens the product's production cycle. Its main purpose is to solve the difficult processing problems of various types of twisted blade profiles in aviation and aerospace products. Due to the characteristics of electrolytic processing itself, such as improper selection of feed parameters during processing, or the presence of conductive particles in the electrolyte, or vibration caused by insufficient rigidity of the machine, a short circuit may be caused during processing. At this time, the processing can be resumed by processing the point of failure. However, in the process of processing, the cathode must exit the work area, and then go to the processing point according to the original trajectory and then process it. Because it is a distortion-type surface processing, it must be reversed strictly in the original trajectory. If there is no back-off function, only the cathode can be disassembled when a fault occurs. After the fault is re-installed and the position is recalibrated, the operation process is very troublesome, and it is difficult to ensure the accuracy of the re-setting tool and the accuracy of machining.
2 The realization of development and surface fitting methods
2.1 Realization of Extrusion Movement Numerically Controlled Extrusion Electrolytic machining is mainly aimed at machining a type of ruled surface represented by the twisted blade profile of the entire impeller. No matter whether the rotating cathode or non-rotating cathode is used, multi-axis linkage (more than four axes) is required. The ideal method is to design a special CNC machining machine and a dedicated CNC system. However, due to the complex forming rules of CNC machining and the limitation of multi-axis linkage control technology, a comprehensive control system that considers various parameters at home and abroad It has not been reported yet that we adopt the improved economical numerical control system to realize multi-axis linkage NC development. For the five-axis electrolytic machining machine tool, the control scheme of the combination of the upper and lower position machines is adopted. That is, each axis of the machine tool consists of a set of reliable Economical numerical control unit control, as shown in Figure 1.
Fig.1 Principle of multi-axis NC generative movement
2.2 Fitting the surface The upper computer divides the blade surface interpolation into a number of surface patches, and then applies ruled surface fitting to each surface, thereby simplifying the trajectory control of each axis. Through post-processing to generate the numerical control code of each axis, it is transmitted from the communication port to the lower machine to control the linkage processing of each numerical control unit. This scheme better overcomes the disadvantages of the costly introduction of foreign CNC systems and the insufficiency of the stability of domestic multi-axis systems, and each axis has a considerable degree of regulation independence, which brings great convenience to system debugging. It is important to solve the problem of synchronization and linkage between the axes through specific programming techniques (this technology has already applied for patents for inventions), and through process experiments, the results are good.
3 The realization of the original trace back function of the cathode
The retreat of the cathode along the original trajectory is the reverse process of feed processing, and it is also the inverse problem of the feed process. In order to obtain the trajectory of the cathode retreat, the usual method is to obtain the actual position of the cathode edge by the position of the center point of the cathode pendulum shaft (the position at the time of failure and stop feeding). This position is used as the starting point and the original The processing surface is fitted and interpolated to obtain the trajectory coordinates of the cathode retreat, and the trajectory of the center point of the cathode pendulum shaft is further calculated to form the NC code of the regression; while the electrolytic processing is a gap processing, and the machining gap is much larger than the interpolation. Complementary errors, therefore, can be avoided by re-interpolation, fitting calculations, and programming is straightforward because the NC code that is returned directly from the numerical control code sent by the control processing is obtained. The principle is shown in Figure 2: The program is mainly composed of two parts. One is to obtain the interrupt instruction number. Based on the system coordinate at the time of the fault stop, it obtains the interrupt command number of the CNC system at this time. Because the system fails to stop urgently, the current command number is not displayed; the second is the segment code analysis subroutine. It obtains the NC code back by analyzing the feed code.
Figure 2 The principle of the original track backtracking
3.1 The acquisition of the program interruption instruction number starts, and the coordinate value Z of the reference axis is input when the failure stops. Judge that the original numerical control instruction is relative programming or absolute programming. If absolute programming, Zi-Z is calculated segment by segment (Zi is the Z coordinate value of the i-th instruction), and if relative programming, Wi-Z is calculated segment by segment (Wi is the Z-axis relative coordinate value of the i-th instruction) until CNC The end of the instruction. Obtain the interrupt instruction number according to the number of symbol changes of Zi-Z or Wi-Z. If the variable number is once, then it can be concluded that i-1 is the current instruction number. If the variable number is more than one, indicating that the cathode trajectory coordinate Z is non-monotonically increasing or decreasing, the X coordinate value should be input to further determine the current instruction number k. . Then from the k-th segment instruction, the segment number is fetched in the decreasing direction of the instruction number, and a segment code analysis subroutine is called to generate a cathode fallback numerical control code.
3.2 Segment Code Analysis The subroutine segment code analysis subroutine analyzes a section of code, including the programming mode, whether it is a straight line or a circular arc, and whether the arc is to further judge whether the circle is a circle or a circle and whether there is a quadrant. Then, the coordinates of the corresponding rollback segment code are obtained according to the coordinates of the feed segment code. FIG. 3 is an example of the straight line machining of the first quadrant. Relative to the programming mode, an example of a regression code is obtained. The original code G02 U (x2-x1) W (z2-z1) I (x0-x1) K (z0-z1) Fv, v is the speed of feed processing. Move the coordinate system UW to the end of the position of the segment instruction, which is expressed in a relatively programmatic manner. The formed segment code is G03 U-x1 W-z1 I(x0-x2) K(z0-z2)Fv',v 'It is the speed of retreat (can be set according to process requirements). If the fault stops the command segment, the coordinates at the stop position are used instead of (x2, z2). The regression code of the straight-line segment instruction is relatively simple, which is omitted here.
Figure 3 Calculation Example
During the development of the program, the randomness of the fault point, the control accuracy of the machine tool itself and the numerical control system, and the control of the backlash compensation amount are fully considered. Fully considered the invalid instruction code that may be caused when the small feed amount may be caused due to the difference in the effective digits of the upper and lower machines. After on-line examination and program operation, it can fully realize the requirement that the cathode in the NC development electrolysis process be retracted in the original trajectory.
4 Conclusion
The numerical control of the electroforming process of the cathode original path retreat and refeed processing is a key technical problem that must be solved in numerical control electrolytic machining. The program has been integrated with the original computer-aided programming system in the same interface, the application is convenient and reliable, and good experimental results are obtained.
Stainless Steel Sheet Metal CNC Laser Cutting Parts
(1) It is used as a variety of industrial metal parts that like electronic component, auto spare parts,
home appliance, industrial equipment...etc.Material based on SPCC and SGCC, stainless steel, aluminum alloy5052, 6063, 6061, Stainless steel 304, 316, 201, carbon steel,etc.
(2) Software for specification drawings: Pro/E, Auto CAD, PDF, IGES/IGS, STP/STEPS, X_T, DXF etc..
(3) High precision as following: Carbon steel: 0.5mm~16mm,Stainless steel: 1mm~8mm,Aluminum alloy: 1mm~8mm,Brass: 1mm~4mm.
Accuracy: positioning accuracy: ±0.03mm, Repeated positioning accuracy: ±0.02mm
(4) Main poduction machine: Laser cutting machine, CNC punching machine, welder, CNC bending machine
(5) Surface treatment: Polishing, grinding, gavanized, powder coating, nickel, zinc, chrome, silver, gold plating etc.
(6) For packing: A variety of packing methods can be used according to customers' requirement, such as carton , wood box, wood crate and pallet etc.
Stainless Steel Laser Cutting,Custom Laser Cutting,Cnc Laser Cutting Machine,Laser Cutting Machine
Nanpi Jian Tong Hardware Manufacturing Co., Ltd. , https://www.sheetmetals.nl