CN107451382B - Control method for surface appearance of high-speed cutting workpiece - Google Patents
Control method for surface appearance of high-speed cutting workpiece Download PDFInfo
- Publication number
- CN107451382B CN107451382B CN201710851741.4A CN201710851741A CN107451382B CN 107451382 B CN107451382 B CN 107451382B CN 201710851741 A CN201710851741 A CN 201710851741A CN 107451382 B CN107451382 B CN 107451382B
- Authority
- CN
- China
- Prior art keywords
- cutting
- force
- workpiece
- angle
- tool
- 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.)
- Expired - Fee Related
Links
- 238000005520 cutting process Methods 0.000 title claims abstract description 157
- 238000000034 method Methods 0.000 title claims abstract description 13
- 238000003801 milling Methods 0.000 claims abstract description 5
- 238000006073 displacement reaction Methods 0.000 claims description 12
- 230000004069 differentiation Effects 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 9
- 238000003754 machining Methods 0.000 claims description 8
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 239000011159 matrix material Substances 0.000 claims description 6
- 230000009466 transformation Effects 0.000 claims description 6
- 238000013016 damping Methods 0.000 claims description 3
- 238000013507 mapping Methods 0.000 claims description 3
- 238000010008 shearing Methods 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 claims 1
- 238000012876 topography Methods 0.000 claims 1
- 238000005516 engineering process Methods 0.000 abstract description 3
- 238000007514 turning Methods 0.000 abstract description 2
- 230000003746 surface roughness Effects 0.000 description 3
- 238000013528 artificial neural network Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000000611 regression analysis Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/10—Geometric CAD
- G06F30/17—Mechanical parametric or variational design
Landscapes
- Physics & Mathematics (AREA)
- Geometry (AREA)
- Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Pure & Applied Mathematics (AREA)
- Mathematical Optimization (AREA)
- Mathematical Analysis (AREA)
- Computer Hardware Design (AREA)
- Evolutionary Computation (AREA)
- General Engineering & Computer Science (AREA)
- Computational Mathematics (AREA)
- Numerical Control (AREA)
- Turning (AREA)
Abstract
The patent discloses a control method for high-speed cutting processing workpiece surface appearance, which can be widely applied to mechanical processing technologies such as turning, milling, planing, drawing, inserting and the like, can be used for processing a plane and controlling the surface appearance of a processed curved surface, and realizes the control of the roughness of the preset surface of a processed workpiece.
Description
Technical Field
The invention belongs to the technical field of machining processes, and relates to a control method for the surface appearance of a high-speed cutting workpiece.
Background
With the ever-developing scientific technology, the higher requirements on the surface appearance of the workpiece in the high-speed cutting process are provided, that is, the control method for obtaining the preset roughness of the surface of the machined workpiece is far from enough, and the control on the appearance (wave crest, wave trough, spacing thereof and the like) of different preset positions on the surface of the workpiece needs to be realized. In the traditional machining, the surface roughness of a workpiece machined in a cutting mode is not predicted, and a method for optimizing cutting parameters according to the predicted surface roughness cannot control the surface appearance of the workpiece machined at a high speed.
At present, only a prediction method of the surface roughness of a cutting workpiece exists, and methods such as regression analysis and neural network are adopted, so that the processing control of the preset appearance of the preset surface of the workpiece cannot be realized, and the requirements are difficult to meet. The invention can realize the control of the surface appearance only by carrying out a plurality of groups of cutting processing tests with preset cutting parameters, and has the advantages of low cost, high efficiency and high precision.
Disclosure of Invention
In order to overcome the defects of the prior art, the patent discloses a control method for the surface appearance of a high-speed cutting workpiece, which can be widely applied to mechanical processing technologies such as turning, milling, planing, drawing, inserting and the like, can be used for controlling the surface appearance of a processing plane and a processing curved surface, and realizes the control of the preset roughness of the surface of the processing workpiece.
In order to achieve the purpose, the technical scheme of the invention is as follows:
the invention mainly comprises a three-dimensional surface profiler and a data processing system, the core of the invention is the data processing system, and the concrete steps are as follows: .
A control method for high-speed cutting processing workpiece surface appearance is characterized by comprising the following steps:
determining geometric parameters of a cutter, wherein the geometric parameters comprise a front angle gamma, a rear angle, an installed blade inclination angle and parameters of a manufacturing material, and the parameters of the manufacturing material comprise hardness and density;
step two, obtaining 1 or more groups of tangential, radial and axial cutting force coefficients under different cutting parameters: ktc,Krc,Kac,Kte,Kre,KaeWherein, K istcRepresenting the tangential force coefficient; krcRepresents the radial force coefficient; kacRepresenting the axial force coefficient; kteExpressing the coefficient of tangential edge force, KreRepresenting the radial cutting edge force coefficient; kaeRepresenting the axial edge force coefficient, t the tangential direction, r the radial direction, a the axial direction, c the force coefficient, e the edge force coefficient, then:
β＝arcsin(sinη·sini+cosη·cosi·cosα)
gamma is the tool rake angle, η denotes the angle of the chip flow direction to the direction perpendicular to the tool cutting edge, i denotes the angle of the cutting edge to the direction perpendicular to the workpiece motion,
is the normal shear angle of the cutting tool shear plane, theta is the position angle of the cutting tool during cutting, β is the effective rake angle, α is the tool relief angle, h is the cutting thickness, dMeans differentiation; z represents the z direction of the workpiece coordinate system x-y-z, dz is an axial cutting depth infinitesimal, d represents differentiation, and h represents cutting thickness; fx represents the x-direction cutting force; fy represents a y-direction cutting force, and Fz represents a z-direction cutting force;
and step three, carrying out a high-speed milling test under the set cutting force coefficient to obtain the surface profile of the machined workpiece, wherein the surface profile of the workpiece is formed by the relative displacement between the cutter and the workpiece in a cutting machining system, namely if no vibration exists, the workpiece is an ideal surface, and the surface profile is equal to the relative displacement X between the cutter and the workpiece1(T)；
X, Y and Z represent the relative displacement of the tool tip and the workpiece in the X, Y and Z directions under the workpiece coordinate system X-Y-Z.
Step four, establishing a cutting force model according to the instantaneous rigid force model of the high-speed cutting machining:
Ft＝∫Ktc·h·dz+Kte·ds
dFt＝Ktc·h·dz+Kte·ds
dFr＝Krc·h·dz+Kre·ds
dFa＝Kac·h·dz+Kae·ds
wherein, FtDenotes the tangential cutting force, FrDenotes the radial cutting force, FaThe axial cutting force is shown, and h is the cutting thickness; z represents the z-direction of the object coordinate system x-y-z; dFtIs a tangential force infinitesimal, dFrIs a radial force infinitesimal, dFaIs axial force infinitesimal, ds is cutting edge length infinitesimal, dz is axial cutting depth infinitesimalElement, d represents differentiation, h represents cutting thickness;
and step five, establishing a dynamic model of the relative motion of the high-speed cutting workpiece and the cutter according to a mechanical vibration theory, wherein the dynamic model comprises the following steps:
wherein M is1For cutting system equivalent mass, C1(T) is the equivalent damping coefficient of the cutting system, K1(T) is the equivalent stiffness of the cutting system, f1(T) cutting force, x1(T) represents a vibration displacement function, T represents time;
step six, converting the t-r-a coordinate cutting force of the cutting surface of the cutter into an x-y-z coordinate cutting force through coordinates:
wherein, theta1，β1When the t-r-a coordinate of the cutting surface of the cutter is converted to a coordinate system x-y-z, the rotating angle of the coordinate of the cutting surface around the a axis and the rotating angle around the t axis are respectively; a. the3-rRepresenting the rotation theta of the t-r-a coordinate of the cutting surface of the tool about the a-axis1A transformation matrix of angles, r represents the radial direction of the cutting process; a. ther-aRepresenting the rotation theta of the t-r-a coordinate of the cutting surface of the tool about the a-axis1Rotation β of coordinate system around t-axis after angular rotation1A coordinate transformation matrix of the angle; fx represents the x-direction cutting force; fy represents a y-direction cutting force, and Fz represents a z-direction cutting force;
seventhly, obtaining enough three or more groups of surface profile shapes X1(T), i.e. M is obtained1，C1(T)，K1(T) establishing a mapping rule of cutting processing and workpiece surface appearance;
step eight, obtaining the geometric parameters and cutting parameters of the cutter material required by the surface profile appearance X (T) of any workpiece under the same high-speed cutting machine tool through the dynamic model in the step five; the control of the surface appearance of the high-speed cutting processing is realized.
In a further improvement, in the third step, the surface profile of the machined workpiece is obtained by a three-dimensional surface profiler.
Detailed Description
Example 1
A control method for high-speed cutting processing workpiece surface appearance comprises the following steps:
determining geometric parameters of a cutter, wherein the geometric parameters comprise a front angle gamma, a rear angle, an installed blade inclination angle and parameters of a manufacturing material, and the parameters of the manufacturing material comprise hardness and density;
step two, obtaining 1 or more groups of tangential, radial and axial cutting force coefficients under different cutting parameters: ktc，Krc，Kac，Kte，Kre，KaeWherein, K istcRepresenting the tangential force coefficient; krcRepresents the radial force coefficient; kacRepresenting the axial force coefficient; kteExpressing the coefficient of tangential edge force, KreRepresenting the radial cutting edge force coefficient; kaeRepresenting the axial edge force coefficient, t the tangential direction, r the radial direction, a the axial direction, c the force coefficient, e the edge force coefficient, then:
β＝arcsin(sinη·sini+cosη·cosi·cosα)
gamma is the tool rake angle, η denotes the angle of the chip flow direction to the direction perpendicular to the tool cutting edge, i denotes the angle of the cutting edge to the direction perpendicular to the workpiece motion,
the cutting tool cutting depth is a normal cutting angle of a cutting tool shearing surface, theta is a position angle of the cutting tool in the cutting process, β is an effective front angle, α is a cutting tool rear angle, h is a cutting thickness, d is a differentiation value, z is the z direction of a workpiece coordinate system x-y-z, dz is an axial cutting depth infinitesimal, d is a differentiation value, h is a cutting thickness value, Fx is an x-direction cutting force, Fy is a y-direction cutting force, and Fz is a z-direction cutting force;
thirdly, a high-speed milling test is carried out under the set cutting force coefficient, the surface profile of the processed workpiece is obtained through a three-dimensional surface profile instrument, the surface profile of the workpiece is formed by the relative displacement between a cutter and the workpiece in a cutting processing system, namely if no vibration exists and the workpiece is an ideal surface, the surface profile is equal to the relative displacement X between the cutter and the workpiece1(T)；
X, Y and Z represent the relative displacement of the tool tip and the workpiece in the X, Y and Z directions under the workpiece coordinate system X-Y-Z.
Step four, establishing a cutting force model according to the instantaneous rigid force model of the high-speed cutting machining:
Ft＝∫Ktc·h·dz+Kte·ds
Fr＝∫Krc·h·dz+Kre·ds
Fa＝∫Kac·h·dz+Kae·ds
dFt＝Ktc·h·dz+Kte·ds
dFr＝Krc·h·dz+Kre·ds
dFa＝Kac·h·dz+Kae·ds
wherein, FtDenotes the tangential cutting force, FrDenotes the radial cutting force, FaThe axial cutting force is shown, and h is the cutting thickness; z represents the z-direction of the object coordinate system x-y-z; dFtIs a tangential force infinitesimal, dFrIs a radial force infinitesimal, dFaThe axial force is a infinitesimal, ds is a cutting edge length infinitesimal, dz is an axial cutting depth infinitesimal, d represents differentiation, and h represents cutting thickness;
and step five, establishing a dynamic model of the relative motion of the high-speed cutting workpiece and the cutter according to a mechanical vibration theory, wherein the dynamic model comprises the following steps:
wherein M is1For cutting system equivalent mass, C1(T) is the equivalent damping coefficient of the cutting system, K1(T) is the equivalent stiffness of the cutting system, f1(T) represents a cutting force, x1(T) represents a vibration displacement function, T represents time;
step six, converting the t-r-a coordinate cutting force of the cutting surface of the cutter into an x-y-z coordinate cutting force through coordinates:
wherein, theta1，β1When the t-r-a coordinate of the cutting surface of the cutter is converted to a coordinate system x-y-z, the rotating angle of the coordinate of the cutting surface around the a axis and the rotating angle around the t axis are respectively; a. the3-rRepresenting the rotation theta of the t-r-a coordinate of the cutting surface of the tool about the a-axis1A transformation matrix of angles, r represents the radial direction of the cutting process; a. ther-aRepresenting the t-r-a coordinate of the cutting face of the toolRotation theta about axis a1Rotation β of coordinate system around t-axis after angular rotation1A coordinate transformation matrix of the angle; fx represents the x-direction cutting force; fy represents a y-direction cutting force, and Fz represents a z-direction cutting force;
seventhly, obtaining enough three or more groups of surface profile shapes X1(T), i.e. M is obtained1，C1(T)，K1(T) establishing a mapping rule of cutting processing and workpiece surface appearance;
step eight, obtaining the surface profile shape X of any workpiece under the same high-speed cutting machine tool through the dynamic model in the step five1(T) the required geometrical parameters of the tool material, cutting parameters; the control of the surface appearance of the high-speed cutting processing is realized.
Claims (2)
1. A control method for high-speed cutting processing workpiece surface appearance is characterized by comprising the following steps:
determining geometric parameters of a cutter, wherein the geometric parameters comprise a front angle gamma, a rear angle, an installed blade inclination angle and parameters of a manufacturing material, and the parameters of the manufacturing material comprise hardness and density;
step two, obtaining 1 or more groups of tangential, radial and axial cutting force coefficients under different cutting parameters: ktc，Krc，Kac，Kte，Kre，KaeWherein, K istcRepresenting the tangential force coefficient; krcRepresents the radial force coefficient; kacRepresenting the axial force coefficient; kteExpressing the coefficient of tangential edge force, KreRepresenting the radial cutting edge force coefficient; kaeRepresenting the axial edge force coefficient, t the tangential direction, r the radial direction, a the axial direction, c the force coefficient, e the edge force coefficient, then:
β＝arcsin(sinη·sini+cosη·cosi·cosα)
gamma is the tool rake angle, η denotes the angle of the chip flow direction to the direction perpendicular to the tool cutting edge, i denotes the angle of the cutting edge to the direction perpendicular to the workpiece motion,
the cutting tool cutting depth is a normal cutting angle of a cutting tool shearing surface, theta is a position angle of the cutting tool in the cutting process, β is an effective front angle, α is a cutting tool rear angle, h is a cutting thickness, d is a differentiation value, z is the z direction of a workpiece coordinate system x-y-z, dz is an axial cutting depth infinitesimal, d is a differentiation value, h is a cutting thickness value, Fx is an x-direction cutting force, Fy is a y-direction cutting force, and Fz is a z-direction cutting force;
and step three, carrying out a high-speed milling test under the set cutting force coefficient to obtain the surface profile of the machined workpiece, wherein the surface profile of the workpiece is formed by the relative displacement between the cutter and the workpiece in a cutting machining system, namely if no vibration exists, the workpiece is an ideal surface, and the surface profile is equal to the relative displacement X between the cutter and the workpiece1(T)；
X, Y and Z represent the relative displacement of the tool tip and the workpiece in the X, Y and Z directions under the workpiece coordinate system X-Y-Z.
Step four, establishing a cutting force model according to the instantaneous rigid force model of the high-speed cutting machining:
Ft＝∫Ktc·h·dz+Kte·ds
Fr＝∫Krc·h·dz+Kre·ds
Fa＝∫Kac·h·dz+Kae·ds
dFt＝Ktc·h·dz+Kte·ds
dFr＝Krc·h·dz+Kre·ds
dFa＝Kac·h·dz+Kae·ds
wherein, FtDenotes the tangential cutting force, FrDenotes the radial cutting force, FaThe axial cutting force is shown, and h is the cutting thickness; z represents the z-direction of the object coordinate system x-y-z; dFtIs a tangential force infinitesimal, dFrIs a radial force infinitesimal, dFaThe axial force is a infinitesimal, ds is a cutting edge length infinitesimal, dz is an axial cutting depth infinitesimal, d represents differentiation, and h represents cutting thickness;
and step five, establishing a dynamic model of the relative motion of the high-speed cutting workpiece and the cutter according to a mechanical vibration theory, wherein the dynamic model comprises the following steps:
wherein M is1For cutting system equivalent mass, C1(T) is the equivalent damping coefficient of the cutting system, K1(T) is the equivalent stiffness of the cutting system, f1(T) represents a cutting force, x1(T) represents a vibration displacement function, T represents time;
step six, converting the t-r-a coordinate cutting force of the cutting surface of the cutter into an x-y-z coordinate cutting force through coordinates:
wherein, theta1，β1From the t-r-a coordinate of the cutting surface of the tool to the coordinate system x-During y-z conversion, the rotation angle of the cutting face coordinate around the a axis and the rotation angle around the t axis; a. the3-rRepresenting the rotation theta of the t-r-a coordinate of the cutting surface of the tool about the a-axis1A transformation matrix of angles, r represents the radial direction of the cutting process; a. ther-aRepresenting the rotation theta of the t-r-a coordinate of the cutting surface of the tool about the a-axis1Rotation β of coordinate system around t-axis after angular rotation1A coordinate transformation matrix of the angle; fx represents the x-direction cutting force; fy represents a y-direction cutting force, and Fz represents a z-direction cutting force;
seventhly, obtaining enough three or more groups of surface profiles X1(T), i.e. M is obtained1，C1(T)，K1(T) establishing a mapping rule of cutting processing and workpiece surface appearance;
step eight, obtaining the surface profile X of any workpiece under the same high-speed cutting machine tool through the dynamic model in the step five1(T) the required geometrical parameters of the tool material, cutting parameters; the control of the surface appearance of the high-speed cutting processing is realized.
2. The method for controlling the surface topography of a workpiece machined at high speed according to claim 1, wherein in the third step, the surface profile of the workpiece after machining is obtained by a three-dimensional surface profiler.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710851741.4A CN107451382B (en) | 2017-09-19 | 2017-09-19 | Control method for surface appearance of high-speed cutting workpiece |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710851741.4A CN107451382B (en) | 2017-09-19 | 2017-09-19 | Control method for surface appearance of high-speed cutting workpiece |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107451382A CN107451382A (en) | 2017-12-08 |
| CN107451382B true CN107451382B (en) | 2020-05-12 |
Family
ID=60497793
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710851741.4A Expired - Fee Related CN107451382B (en) | 2017-09-19 | 2017-09-19 | Control method for surface appearance of high-speed cutting workpiece |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107451382B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109332820B (en) * | 2018-09-29 | 2020-06-02 | 中南大学 | A kind of ultrasonic vibration machining gear tooth surface topography machining and control method |
| CN109290638B (en) * | 2018-09-29 | 2019-09-13 | 湖南工学院 | A high-speed dry milling method for surface topography control of workpieces |
| CN109324567B (en) * | 2018-09-29 | 2020-05-22 | 湖南工学院 | Control method for processing surface appearance of ultrasonic vibration processing workpiece |
| CN111241707B (en) * | 2020-02-14 | 2023-07-07 | 中国航空制造技术研究院 | Calculation method for five-axis numerical control machining full-path milling force of complex curved surface |
| CN112571150B (en) * | 2020-12-09 | 2022-02-01 | 中南大学 | Nonlinear method for monitoring thin plate machining state of thin plate gear |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104392090B (en) * | 2014-09-26 | 2017-12-22 | 北京理工大学 | The construction method of aluminum alloy materials end mill cutting force and machining distorted pattern |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140012404A1 (en) * | 2012-07-06 | 2014-01-09 | Caterpillar Inc. | Methods and systems for machine cut planning |
-
2017
- 2017-09-19 CN CN201710851741.4A patent/CN107451382B/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104392090B (en) * | 2014-09-26 | 2017-12-22 | 北京理工大学 | The construction method of aluminum alloy materials end mill cutting force and machining distorted pattern |
Non-Patent Citations (1)
| Title |
|---|
| 微切削加工Al7050-T7451过程切屑形貌及尺度效应研究;周军等;《山东大学学报(工学版)》;20100630;第40卷(第3期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN107451382A (en) | 2017-12-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107451382B (en) | Control method for surface appearance of high-speed cutting workpiece | |
| Altıntas et al. | Mechanics and dynamics of ball end milling | |
| Zhu et al. | Research on rotary surface topography by orthogonal turn-milling | |
| US9696707B2 (en) | Method of controlling tool orientation and step-over distance in face milling of curvilinear surfaces | |
| CN107944176A (en) | A kind of rose cutter multi-axis milling titanium alloy Prediction Method of Milling Forces | |
| CN102156441B (en) | Method for machining outer surface of bent pipe by three-shaft numerically controlled milling | |
| CN103862346B (en) | Instant center-free envelope grinding method for spiral curved surface of micro milling cutter | |
| Ikua et al. | Prediction of cutting forces and machining error in ball end milling of curved surfaces-II experimental verification | |
| Fomin et al. | Geometrical errors of surfaces milled with convex and concave profile tools | |
| CN104462775B (en) | A kind of Five-axis NC Machining Center Milling Force computational methods | |
| Fomin | Limiting product surface and its use in profile milling design operations | |
| CN106980720A (en) | Thin-wall part milling distortion inaccuracy Forecasting Methodology | |
| Gao et al. | Effects of machining inclination angles on microgroove quality in micro ball end milling of Ti-6Al-4V | |
| CN109299581B (en) | End mill milling force prediction method combined with curved surface interpolation | |
| CN112883505A (en) | Ultra-precise end face turning surface modeling method considering relative vibration of cutter workpiece | |
| Fomin | Determining undeformed chip thickness models in milling and its verification during wood processing | |
| CN114578752B (en) | Corner control method for ultrasonic cutting straight-edge sharp knife | |
| Bolar et al. | Experimental investigation on surface quality and dimensional accuracy during curvilinear thin-wall machining | |
| CN103286360B (en) | A kind of tangential offset orthogonal turn-milling cutting method | |
| CN204075839U (en) | A kind of double-deck multiple-cutting-edge wire rod quality equipment for cutter positioning | |
| Matsumura et al. | Simulation of drilling process for control of burr formation | |
| WO2021232735A1 (en) | Machining method and machining device having high efficiency and low damage | |
| CN113887023B (en) | Surface quality optimization method for tilt milling of weak rigid features based on analytical force model | |
| Zhu et al. | Modeling and Experimental Investigation of Surface Generation in Diamond Micro-Chiseling | |
| CN103111791A (en) | Vane surface ultrasonic wave machining process |
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 | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20200512 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |