CN-121995848-A - Electric spark machining coordinate acquisition and execution method and system

CN121995848ACN 121995848 ACN121995848 ACN 121995848ACN-121995848-A

Abstract

A method for collecting and executing the coordinates of electric spark machining includes such steps as obtaining the first coordinate position where no interference is generated and the second coordinate position where machining is finished in the calculation environment with three-dimensional geometric processing function, S2 mapping the reference zero point to the physical machining zero point on electric spark machine, S3 automatically exchanging physical electrodes on machine, measuring the geometric deviation of said physical electrodes, writing it in digital control system, and S4 controlling the electrodes to execute electric discharge machining from said first to said second coordinate positions. According to the invention, the coordinates are obtained through simulation, so that the risk of motion interference of the electrode in the complex inner cavity is eliminated in advance, and the problem that blind hole machining cannot intuitively align the tool is solved. And a large amount of coordinate acquisition work is transferred to a computer end, and the machine tool end only needs to execute automatic calibration and machining, so that the downtime waiting time is obviously reduced, and continuous automatic production is realized.

Inventors

MAO JIGANG
Qing Hucheng
LIN WEI
XU DUO

Assignees

陕西东方航空仪表有限责任公司

Dates

Publication Date: 20260508
Application Date: 20251230

Claims (7)

1. The electric spark machining coordinate acquisition and execution method is characterized by comprising the following steps of: S1, in a computing environment with a three-dimensional geometric processing function, taking the center of a designated reference hole on a workpiece design model as a reference zero point, acquiring the target size of a feature to be processed on the workpiece design model, and correcting an electrode design model by combining discharge process parameters to generate an electrode processing model; S2, measuring the actual center position of the specified reference hole on the physical workpiece by using a measuring head on the electric spark machine tool, and setting the origin of a machine tool machining coordinate system at the actual center position so as to finish mapping from the reference zero point to the physical machining zero point; s3, after the physical electrode is automatically replaced on the machine tool, controlling the physical electrode to be in contact with a fixed reference ball on the machine tool for measurement, measuring the geometric deviation of the physical electrode, and writing the deviation into a numerical control system as a tool bias parameter; s4, calling a numerical control program containing the first coordinate position and the second coordinate position, and controlling an electrode to execute electric discharge machining from the first coordinate position to the second coordinate position under a coordinate system subjected to the physical reference mapping and the electrode error compensation correction.
2. The method according to claim 1, wherein in step S1, the discharge process parameters according to which the electrode processing model is determined at least include a single-sided discharge gap and a translational radius, and the compensation formula is: electrode machining model size = target size of feature to be machined-2× (single side discharge gap-translational radius).
3. The method according to claim 1, wherein in step S1, the first coordinate position is obtained by moving the electrode processing model along the axial direction of the feature to be processed, calculating a minimum distance between the outer contour of the electrode processing model and the inner wall of the workpiece design model in real time, and determining an entering position without interference and recording the entering position as the first coordinate position when the minimum distance is greater than zero and the body of the electrode processing model has completely passed through the specified reference hole region.
4. The method according to claim 1, wherein in step S2, the specific process of measuring the actual center position of the specified reference hole on the physical workpiece comprises the steps of controlling the probe to enter the hole, collecting coordinates of at least three points on the hole wall at least two sections with different depths, calculating the center of each section through a space circle fitting algorithm, and determining the center axis of the hole and the specified center coordinates serving as the origin of a machining coordinate system according to the center of each section.
5. The method according to claim 1, wherein in step S3, each time the automatic tool changer of the machine tool completes the clamping of the electrode, the measurement and the bias calculation with reference to the fixed reference ball are automatically performed once, and the calculated tool bias parameters unique to the electrode are updated to the numerical control system in real time.
6. The method according to claim 1, wherein after step 4 is completed, the control electrode is moved into a calibration hole with a known position on the workpiece to perform position measurement, the measured coordinates are compared with the theoretical coordinates, and the processing coordinates which have not been performed are dynamically compensated according to the deviation obtained by the comparison.
7. An automatic coordinate acquisition and execution system for electric discharge machining for implementing the method according to any one of claims 1 to 6, characterized by comprising: the system comprises a coordinate acquisition module, a machining module and a machining module, wherein the coordinate acquisition module operates in a computing environment with a three-dimensional geometric processing function and is used for acquiring a target size of a feature to be machined on a workpiece design model by taking the center of a designated reference hole on the workpiece design model as a reference zero point, correcting the electrode design model by combining discharge process parameters to generate an electrode machining model; the machine tool hardware subsystem comprises an electric spark machine tool body, a measuring head arranged on a machine tool spindle, an automatic tool changing device and a fixed reference ball fixed on a machine tool workbench; The physical mapping module is in communication connection with the machine tool hardware subsystem and is used for controlling the measuring head to measure the actual center position of the physical workpiece corresponding to the designated reference hole, and setting the origin of a machine tool machining coordinate system at the actual center position so as to finish mapping from a reference zero point to a physical machining zero point; The error compensation module is used for controlling the physical electrode to be in contact with the fixed reference ball for measurement after the automatic tool changing device finishes the assembly of the physical electrode, measuring the geometric deviation of the physical electrode, and writing the deviation into the numerical control system as a tool bias parameter; And the numerical control execution module is used for calling a numerical control program comprising the first coordinate position and the second coordinate position, and controlling an electrode to execute electric discharge machining in a coordinate system with the origin of the coordinate system determined by the physical mapping module and the tool bias parameter set by the error compensation module.

Description

Electric spark machining coordinate acquisition and execution method and system Technical Field The invention belongs to the technical field of automatic electric spark machining, and relates to an electric spark machining coordinate acquisition and execution method and system. Background The electric spark machining technology is a technology for machining metal by utilizing electric energy, and is particularly suitable for difficult-to-cut materials and parts with complex shapes. In the existing precision manufacturing fields of aviation, molds and the like, a single workpiece often contains tens or even more electric spark machining features, such as special-shaped holes, deep grooves and the like. In the existing electric spark machining process, manual operation is highly relied, particularly in the process of processing tens of electric spark characteristics, operators need to manually perform the steps of discharging oil, disassembling the electrode, assembling the electrode, straightening by using a dial gauge electrode, leveling the electrode, separating a workpiece, oiling, calibrating and the like every time the electrode is replaced. The problem is that the machine tool is in a stop waiting state most of the time, and the production efficiency is extremely low. And moreover, the manual tool setting and alignment are easy to generate reading errors, so that the relative positions of the electrode and the workpiece are difficult to visually judge for complex holes positioned on a deep cavity or an inclined plane, and tool collision accidents or machining position deviations are easy to occur. Although the conventional CAM software can generate a virtual path, an automatic correction mechanism for a physical clamping error is lacking, and accurate closed-loop mapping from the virtual path to a physical machine tool is difficult to realize. Disclosure of Invention In view of this, the invention provides a method and a system for collecting and executing electric spark machining coordinates, which eliminate the manual tool setting link and improve the machining efficiency and quality. The technical scheme adopted by the invention is that the electric spark machining coordinate acquisition and execution method is characterized by comprising the following steps of: S1, in a computing environment with a three-dimensional geometric processing function, taking the center of a designated reference hole on a workpiece design model as a reference zero point, acquiring the target size of a feature to be processed on the workpiece design model, and correcting an electrode design model by combining discharge process parameters to generate an electrode processing model; S2, measuring the actual center position of the specified reference hole on the physical workpiece by using a measuring head on the electric spark machine tool, and setting the origin of a machine tool machining coordinate system at the actual center position so as to finish mapping from the reference zero point to the physical machining zero point; s3, after the physical electrode is automatically replaced on the machine tool, controlling the physical electrode to be in contact with a fixed reference ball on the machine tool for measurement, measuring the geometric deviation of the physical electrode, and writing the deviation into a numerical control system as a tool bias parameter; s4, calling a numerical control program containing the first coordinate position and the second coordinate position, and controlling an electrode to execute electric discharge machining from the first coordinate position to the second coordinate position under a coordinate system subjected to the physical reference mapping and the electrode error compensation correction. Further, in step S1, the discharge process parameters according to which the electrode processing model is determined at least include a unilateral discharge gap and a translational radius, and the compensation formula is as follows: electrode machining model size = target size of feature to be machined-2× (single side discharge gap-translational radius). Further, in step S1, the specific manner of obtaining the first coordinate position is to move the electrode processing model along the axis direction of the feature to be processed, calculate the minimum distance between the outer contour of the electrode processing model and the inner wall of the workpiece design model in real time, and determine an entering position without interference and record the entering position as the first coordinate position when the minimum distance is greater than zero and the main body of the electrode processing model has completely passed through the specified reference hole region. Further, in step S2, the specific process of measuring the actual center position of the specified reference hole on the physical workpiece comprises the steps of controlling a measuring head to enter the hole, collecting coordinates o