CN110253151B - Method for improving FSS laser etching processing precision of surface of antenna reflector - Google Patents
Method for improving FSS laser etching processing precision of surface of antenna reflector Download PDFInfo
- Publication number
- CN110253151B CN110253151B CN201910464006.7A CN201910464006A CN110253151B CN 110253151 B CN110253151 B CN 110253151B CN 201910464006 A CN201910464006 A CN 201910464006A CN 110253151 B CN110253151 B CN 110253151B
- Authority
- CN
- China
- Prior art keywords
- antenna reflector
- profile data
- laser etching
- measuring
- point
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
- B23K26/362—Laser etching
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/70—Auxiliary operations or equipment
- B23K26/702—Auxiliary equipment
- B23K26/705—Beam measuring device
Abstract
The invention relates to a method for improving the surface FSS laser etching processing precision of an antenna reflector, belonging to the technical field of FSS processing of antenna reflectors. The method of the invention firstly proposes that the designed profile data for laser etching is corrected by adopting the actually measured profile data of the antenna reflector, namely the actually measured profile data is converted into the designed profile data to be contrasted and analyzed under the same coordinate system, and the designed profile data for laser etching is corrected according to errors, thereby improving the subsequent FSS laser etching processing precision of the antenna surface, and the pattern size precision and the relative position precision of the FSS oscillator on the surface of the antenna reflector manufactured by adopting the method are both superior to 15 mu m.
Description
Technical Field
The invention relates to a method for improving the laser etching processing precision of an antenna reflector surface FSS (frequency selective surface), belonging to the technical field of antenna reflector FSS processing.
Background
Frequency Selective Surface (FSS) refers to a periodic gap distributed on a conductive metal Surface or a periodic metal patch arranged on a medium to achieve the purpose of Frequency selection, i.e., a spatial filter. The three-dimensional curved surface laser etching technology is a frequency selective surface manufacturing method with the most advantages and potential in the current antenna reflector FSS manufacturing.
The satellite antenna shell is made of a composite material with small mass, high specific strength, good chemical stability, fatigue resistance, shock resistance and the like. At present, the composite material antenna shell is mostly processed by one-step molding through a hot pressing process, and although a processing mold has higher precision, the molded surface error caused by resilience in the hot pressing molding process of the composite material cannot be completely avoided; in addition, the determination of the antenna target point, the metallization of the surface of the composite material housing, and the like may cause a certain error between the actual antenna profile and the antenna design profile, and the occurrence of the error inevitably causes that the actual antenna profile and the design profile cannot be completely matched. On the other hand, in the laser etching process, the normal etching of the metal film graph is completed by taking the design profile data of the antenna as a reference, namely, an actual workpiece is positioned under the machine coordinate system of the etching equipment through three target points (three points determine one surface), and then the etching processing is performed by controlling the laser processing head to move to the point to be processed on the surface of the design profile model under the machine coordinate system. If the designed profile of the antenna and the actual profile cannot be accurately matched in the actual processing process, the generated error may cause the over-focusing or under-focusing phenomenon during laser etching processing, further cause the defect of incomplete etching of the metal film on the surface of the composite material, and influence the dimensional precision and the position precision of the metal film pattern etching, thereby finally influencing the electrical performance of the antenna.
Disclosure of Invention
The invention provides a method for improving the laser etching precision of an antenna reflector surface FSS (frequency selective surface system), aiming at the problem that the laser etching precision is reduced due to the error between the actual profile and the designed profile of the antenna reflector.
The purpose of the invention is realized by the following technical scheme.
A method for improving the surface FSS laser etching processing precision of an antenna reflector comprises the following steps:
step 1, actually measuring the molded surface of an antenna reflector to be processed by adopting three-dimensional curved surface non-contact measuring equipment;
step 2, converting the actually measured profile data of the antenna reflector into the same coordinate system with the designed profile data through coordinate system conversion software, and comparing and analyzing the two sets of profile data;
step 3, if the error of the profile data is within the allowable error range of laser etching processing, adopting the designed profile data to carry out laser etching processing on the surface of the antenna reflector; if the error of the profile data exceeds the allowable error range of laser etching processing, firstly correcting the designed profile data according to the actually measured profile data to enable the surface of the antenna reflector to be processed to be in the focal depth range of laser processing in the laser etching process, and then carrying out laser etching processing on the surface of the antenna emitter by adopting the corrected designed profile data.
In step 1, the specific steps of testing the profile of the antenna reflector are as follows: firstly, determining coordinates of a center point of a profile of an antenna reflector through mutually symmetrical reference holes of a skirt edge of the antenna reflector, setting the coordinates as an origin of a rectangular coordinate system, and then setting interval step lengths of adjacent measuring points to enable a Z-axis direction change value caused by the interval step lengths to be smaller than a capture range of a TTL coaxial laser system (automatic focusing can be realized during point-to-point measurement in a measurement process of an operating program); then, starting to carry out manual point-by-point measurement along a bus of the antenna reflector according to the interval step length from a central point by utilizing the measurement point function of a measurement module in the three-dimensional curved surface non-contact measurement equipment until the whole bus is measured; converting the rectangular coordinate system taking the central point as the origin of coordinates into a polar coordinate system taking the central point as the origin of coordinates, copying the operation steps of measuring the bus in the step c once at intervals of an angle not greater than 5 degrees around the origin of coordinates along the circumferential direction by utilizing the copying function of a programming module in the three-dimensional curved surface non-contact measuring equipment, and rotating for one circle to finish copying and storing; then, the measuring point function of a measuring module in the three-dimensional curved surface non-contact measuring equipment is operated, automatic point-by-point measurement of each bus line of the molded surface of the reflector is realized (the number of the measured points on each bus line is the number of the measured points in the selected reference bus line in the programming process), and finally X, Y, Z coordinate values of each measuring point in a rectangular coordinate system with the central point of the reflector as the origin of coordinates are output; in addition, rectangular coordinate data of a target point on the molded surface of the antenna emitter is measured by using the measuring point function of a measuring module in the three-dimensional curved surface non-contact measuring equipment.
The method comprises the following steps of: firstly, determining coordinates of a center point of a profile of an antenna reflector through mutually symmetrical reference holes of a skirt edge of the antenna reflector, setting the coordinates as an origin of a rectangular coordinate system, and then setting interval step lengths of adjacent measuring points to enable a Z-axis direction change value caused by the interval step lengths to be smaller than a capture range of a TTL coaxial laser system; and then, measuring once every interval step length along one bus of the antenna reflector from the central point, and after the whole bus is measured, testing the data of other buses on the molded surface of the antenna reflector according to the bus testing method, wherein the interval angle between two adjacent buses is not more than 5 degrees, and finally obtaining X, Y, Z coordinate values of each testing point in a rectangular coordinate system.
In step 2, the profile data of the antenna reflector obtained by measurement is converted into the same coordinate system with the designed profile data by using the target point test data, and the deviation between the actually measured profile data and the designed profile data is compared by an interpolation method, namely the Z value difference delta Z of the point with the same X, Y coordinate value in the two groups of data is compared substantially.
In step 3, the maximum value delta Z of the allowable error of laser etching processingMAXThe method can be determined through experiments, and comprises the following specific steps: the method comprises the steps of performing FSS oscillator graph laser etching on the surface of an antenna reflector sample accompanying test plate along with a furnace by adopting the same laser etching process parameters, performing defocusing etching processing by continuously changing the distance between a laser etching processing head and the surface of the etching test plate, and observing the oscillator graph etching processing effect of sequential etching, thereby obtaining the maximum allowable deviation value of a Z value in the processing process on the premise of ensuring the integrity of an etched oscillator graph, namely delta ZMAX。
If Δ Z in step 2 is less than or equal to Δ ZMAXThen, laser etching processing of the antenna reflector is completed by adopting laser etching processing parameters set according to the design profile data; if Δ Z>ΔZMAXAnd correcting the data of the designed profile, and finishing the laser etching processing of the antenna reflector according to the laser etching processing parameters set by the data of the designed profile. The specific correction method is as follows: the surface of the antenna reflector to be processed is positioned in the laser processing focal depth range (preferably the focal point) in the laser etching process by adjusting the Z-axis height of the design profile data in the laser etching machine processing coordinate systemPosition) and the laser etching error caused by the actual profile data deviation of the antenna reflector is reduced as much as possible, so that the defects that the metal film is not etched cleanly and the like caused by under-focusing or over-focusing in the laser etching process are avoided, and the size precision and the position precision of the etched FSS oscillator graph are further improved.
Has the advantages that:
(1) the invention provides a novel method generally applicable to FSS laser etching processing on the surface of a regular-shape composite material antenna reflector, which can solve the problem of low laser etching processing precision caused by errors of actual profile data and design profile data of the antenna reflector;
(2) the invention provides a new method for measuring the profile of a regular antenna reflector by utilizing the software programming function and the point-by-point measurement function of non-contact three-dimensional curved surface figure measurement and analysis equipment, which comprises the following steps: in the measuring process, a three-dimensional rectangular coordinate system with the central point of the reflector as the origin of coordinates is converted into a polar coordinate system with the central point of the reflector as the origin of coordinates, and the automatic point-by-point measurement of all to-be-measured buses on the surface of the whole reflector is completed through the manual measurement and programming of one reference bus on the surface of the reflector, so that the testing efficiency is further improved compared with a manual point-by-point measurement method;
(3) the method of the invention firstly proposes that the designed profile data for laser etching is corrected by adopting the actually measured profile data of the antenna reflector, thereby further improving the FSS laser etching processing precision of the antenna surface, and the FSS laser etching processing precision is not reported in journals at home and abroad;
(4) the pattern size precision and the relative position precision of the FSS oscillator on the surface of the antenna reflector manufactured by the method are both superior to 15 mu m.
Detailed Description
The present invention is further illustrated by the following detailed description, wherein the processes are conventional unless otherwise specified, and the starting materials are commercially available from a public perspective unless otherwise specified.
Example 1
Preparing a layer of metal aluminum film with the thickness of about 1.5 mu m on the surface of an antenna reflector (the projection caliber is 400mm, the eccentricity is about 1.45) by adopting an arc ion plating method, and performing non-contact measurement on the antenna reflector shell by adopting a three-coordinate measuring system CNC670 (uniaxial test precision is 2 three mu m) to obtain actual profile data; the method comprises the following specific steps of testing actual profile data:
firstly, determining coordinates of a center point of a molded surface of an antenna reflector through eight mutually symmetrical reference holes at the skirt edge of the antenna reflector, and setting the coordinates as an origin of a rectangular coordinate system; because the capture range of the TTL coaxial laser system is 500 micrometers, the interval step length of adjacent measuring points is set to be 3-4 mm (automatic focusing can be realized during point-by-point measurement in the measuring process of the running program); then, manually measuring once every 3-4 mm along one bus of the antenna reflector from a central point by using the measuring point function of a measuring module in a three-coordinate measuring system CNC670 until the whole bus (marked as a reference bus) is measured; converting a rectangular coordinate system taking a central point as a coordinate origin into a polar coordinate system taking the central point as the coordinate origin, copying a measuring reference bus once by using the copying function of a programming module in a three-coordinate measuring system CNC670 around the coordinate origin along the circumferential direction at an angle of 5 degrees (the smaller the interval angle is, the more the number of measured bus bars is), and rotating for one circle to finish copying and storing; then, the measuring point function of a measuring module in a three-coordinate measuring system CNC670 is operated, automatic point-by-point measurement of each bus of the reflector profile is realized (the number of measured points on each bus is the number of points measured by a selected reference bus in the programming process), and finally X, Y, Z coordinate values (DAT format files) of each measuring point in a rectangular coordinate system taking the center point of the reflector as the origin of coordinates are output; in addition, rectangular coordinate data (DAT format file) of a target point on the profile of the antenna emitter is measured by using the measuring point function of a measuring module in a three-coordinate measuring system CNC 670;
according to the test data of the target point, the actual profile data of the antenna obtained by measurement is converted into the same coordinate system with the designed profile data for etching by using CAD software, then, the deviation of the Z value of the same point of X, Y coordinate values in the actually measured profile data and the designed profile data is compared by an interpolation method to be about 0.4mm, and the deviation is more than 0.3mm of the maximum allowable error value of laser etching processing, so that the designed profile data for antenna etching needs to be corrected;
before etching, the antenna reflector is fixed on a three-dimensional curved surface laser etching system processing platform, three target points are selected as positioning points to position the antenna reflector, and because certain deviation exists between design profile data for laser etching and actual profile data, the surface of the antenna reflector to be processed in the etching process can be positioned at a laser processing focus position by properly adjusting a Z value in the positioning target point data (the essence is to adjust the Z value of the design profile data in a laser etching machine coordinate system to be matched with the Z value of the actual profile data in the laser etching machine coordinate system as much as possible), and after the correction is finished, laser etching processing is carried out by adopting laser etching related process parameters set according to the original design profile data.
And (4) performing extraction measurement (40 groups of extraction measurement) on the FSS oscillator pattern on the surface of the antenna reflector after the laser etching processing, wherein the result shows that the dimensional precision and the relative position precision of the etched oscillator pattern are superior to 15 micrometers.
In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (4)
1. A method for improving the surface FSS laser etching processing precision of an antenna reflector is characterized in that: the method comprises the following steps:
step 1, actually measuring the molded surface of an antenna reflector to be processed by adopting three-dimensional curved surface non-contact measuring equipment;
step 2, converting the actually measured profile data of the antenna reflector into the same coordinate system with the designed profile data through coordinate system conversion software, and comparing and analyzing the two sets of profile data;
step 3, if the error of the profile data is within the allowable error range of laser etching processing, adopting the designed profile data to carry out laser etching processing on the surface of the antenna reflector; if the error of the profile data exceeds the allowable error range of laser etching processing, firstly correcting the designed profile data according to the actually measured profile data to enable the surface of the antenna reflector to be processed to be in the focal depth range of laser processing, and then carrying out laser etching processing on the surface of the antenna emitter by adopting the corrected designed profile data;
wherein, in the step 1, the specific steps for testing the profile of the antenna reflector are as follows,
a) determining the coordinate of the center point of the molded surface of the antenna reflector through the mutually symmetrical reference holes of the skirt edges of the antenna reflector and setting the coordinate as the origin of a rectangular coordinate system; b) setting the interval step length of adjacent measuring points, and enabling the Z-axis direction change value caused by the interval step length to be smaller than the capture range of the TTL coaxial laser system; c) measuring once every interval step length from a central point along a bus of the antenna reflector by using the measuring point function of a measuring module in the three-dimensional curved surface non-contact measuring equipment until the whole bus is measured; d) converting the rectangular coordinate system taking the central point as the origin of coordinates into a polar coordinate system taking the central point as the origin of coordinates, copying the operation steps of measuring the bus in the step c once at intervals of an angle not greater than 5 degrees around the origin of coordinates along the circumferential direction by utilizing the copying function of a programming module in the three-dimensional curved surface non-contact measuring equipment, and rotating for one circle to finish copying and storing; e) the measuring point function of a measuring module in the three-dimensional curved surface non-contact measuring equipment is operated, automatic point-by-point measurement of each bus of the molded surface of the reflector is realized, and finally X, Y, Z coordinate values of each testing point in a rectangular coordinate system are output; f) then measuring rectangular coordinate data of a target point on the molded surface of the antenna emitter by using the measuring point function of a measuring module in the three-dimensional curved surface non-contact measuring equipment;
or, firstly, determining the coordinate of the center point of the profile of the antenna reflector through mutually symmetrical reference holes at the skirt edge of the antenna reflector, setting the coordinate as the origin of a rectangular coordinate system, and then setting the interval step length of adjacent measuring points to ensure that the Z-axis direction change value caused by the interval step length is smaller than the capture range of the TTL coaxial laser system; then, measuring once every interval step length from a central point along a bus of the antenna reflector by using the measuring point function of a measuring module in the three-dimensional curved surface non-contact measuring equipment, and after the whole bus is measured, testing the data of other buses on the molded surface of the antenna reflector according to the bus testing method, wherein the interval angle between two adjacent buses is not more than 5 degrees, and finally obtaining X, Y, Z coordinate values of each testing point in a rectangular coordinate system; in addition, rectangular coordinate data of the target point on the antenna transmitter profile is measured.
2. The method for improving the FSS laser etching processing precision of the surface of the antenna reflector as claimed in claim 1, wherein: in step 2, the target point test data is used, coordinate system conversion software is used for converting the profile data of the antenna reflector obtained through measurement into the same coordinate system with the design profile data, and then the Z value difference delta Z of the point with the same X, Y coordinate value in the actually measured profile data and the design profile data is compared through an interpolation method.
3. The method for improving the FSS laser etching processing precision of the surface of the antenna reflector as claimed in claim 1 or 2, wherein the method comprises the following steps: in step 3, determining the maximum value Delta Z of the allowable error of laser etching processingMAXThe specific steps of (A) are as follows,
the method comprises the steps of performing FSS oscillator graph laser etching on the surface of an antenna reflector sample accompanying test plate along with a furnace by adopting the same laser etching process parameters, performing defocusing etching processing by continuously changing the distance between a laser etching processing head and the surface of the etching test plate, and observing the oscillator graph etching processing effect of sequential etching, thereby obtaining the maximum allowable deviation value of a Z value in the processing process on the premise of ensuring the integrity of an etched oscillator graph, namely delta ZMAX。
4. The method for improving the FSS laser etching processing precision of the surface of the antenna reflector as claimed in claim 1, wherein: in step 3, the specific operations for modifying the profile data involved are as follows,
and adjusting the Z-axis height of the design profile data under the processing coordinate system of the laser etching machine to enable the surface of the antenna reflector to be processed to be in the laser processing focal depth range in the laser etching process.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910464006.7A CN110253151B (en) | 2019-05-30 | 2019-05-30 | Method for improving FSS laser etching processing precision of surface of antenna reflector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910464006.7A CN110253151B (en) | 2019-05-30 | 2019-05-30 | Method for improving FSS laser etching processing precision of surface of antenna reflector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110253151A CN110253151A (en) | 2019-09-20 |
| CN110253151B true CN110253151B (en) | 2021-05-28 |
Family
ID=67916048
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910464006.7A Active CN110253151B (en) | 2019-05-30 | 2019-05-30 | Method for improving FSS laser etching processing precision of surface of antenna reflector |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110253151B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112736477A (en) * | 2020-12-14 | 2021-04-30 | 兰州空间技术物理研究所 | Method for accurately positioning whole double-sided metal film graph of antenna reflector |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102683790A (en) * | 2012-04-27 | 2012-09-19 | 西安空间无线电技术研究所 | Laser etching method of curve frequency selecting surface |
| CN204747769U (en) * | 2015-05-27 | 2015-11-11 | 华中科技大学 | Laser on line measurement processes detection device |
| CN105855722A (en) * | 2016-05-06 | 2016-08-17 | 微刻（北京）科技有限公司 | Laser polarization system-based processing method for target pattern on surface of curved-surface part |
| CN107914084A (en) * | 2017-11-16 | 2018-04-17 | 惠州市契贝科技有限公司 | Curved sheets and its method for laser welding, laser welding system |
| CN107941471A (en) * | 2017-11-17 | 2018-04-20 | 全普光电科技(上海)有限公司 | A kind of detection method of free form surface |
| KR20180137071A (en) * | 2017-06-15 | 2018-12-27 | (주)하드램 | Apparatus for 3D laser patterning |
-
2019
- 2019-05-30 CN CN201910464006.7A patent/CN110253151B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102683790A (en) * | 2012-04-27 | 2012-09-19 | 西安空间无线电技术研究所 | Laser etching method of curve frequency selecting surface |
| CN204747769U (en) * | 2015-05-27 | 2015-11-11 | 华中科技大学 | Laser on line measurement processes detection device |
| CN105855722A (en) * | 2016-05-06 | 2016-08-17 | 微刻（北京）科技有限公司 | Laser polarization system-based processing method for target pattern on surface of curved-surface part |
| KR20180137071A (en) * | 2017-06-15 | 2018-12-27 | (주)하드램 | Apparatus for 3D laser patterning |
| CN107914084A (en) * | 2017-11-16 | 2018-04-17 | 惠州市契贝科技有限公司 | Curved sheets and its method for laser welding, laser welding system |
| CN107941471A (en) * | 2017-11-17 | 2018-04-20 | 全普光电科技(上海)有限公司 | A kind of detection method of free form surface |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110253151A (en) | 2019-09-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7869899B2 (en) | Machine tool method | |
| Castro et al. | Laser additive manufacturing of high added value pieces | |
| CN105081883B (en) | Machining center provided with on-machine detection device and using method of machining center | |
| CN107727011B (en) | Method for measuring flatness and profile on line in selective laser melting manufacturing process | |
| CN111347294B (en) | High-gradient optical mirror surface error polishing correction processing method | |
| CN110640146A (en) | Modular material-increasing and material-decreasing composite repair method for defect area of part surface | |
| CN101478078A (en) | Inner and outer shaped surface precise machining process for antenna cover, active position searching method and processing apparatus | |
| CN110253151B (en) | Method for improving FSS laser etching processing precision of surface of antenna reflector | |
| US20150081074A1 (en) | Method for machining the trailing edge of a turbine engine blade | |
| CN108544181B (en) | Repair method for damaged blades of blisk | |
| CN110487464A (en) | A kind of deformable contour measurement method based on residual stress | |
| JP2017527449A (en) | Geometric control and best fit of EDM tools | |
| CN107243715A (en) | The defect correcting method of one class precision castings blank | |
| CN113427133A (en) | Laser equipment and method for guiding automatic processing based on three-dimensional vision online measurement | |
| CN110153643A (en) | A kind of increase and decrease material manufacturing process accumulated error removing method | |
| CN111069973B (en) | Method and device for quickly aligning complex-shape casting | |
| CN111189389A (en) | Method and device for detecting damage degree of ridge | |
| CN109323643B (en) | Rapid detection device and method for blade profile of blisk subjected to electrolytic rough machining | |
| CN110860947B (en) | Positioning and aligning method | |
| CN113029026A (en) | Online multi-parameter detection method for special-shaped air film hole of engine flame tube | |
| CN112526925A (en) | Profile finish machining method based on three-dimensional cam profile materialized model deviation compensation | |
| CN217096927U (en) | Numerical control machine tool knife repairing detection system | |
| CN113532313B (en) | Method for designing machining standard of combustion chamber shell | |
| CN115507803A (en) | Method, device and equipment for machining and detecting turbine blade | |
| US11208891B2 (en) | Method of repairing a firtree feature with wire electrical discharge machining |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |