CN114453641B

CN114453641B - Six-axis linkage machine tool weak electricity control system, six-axis linkage machine tool and milling method

Info

Publication number: CN114453641B
Application number: CN202210101777.1A
Authority: CN
Inventors: 陈明君; 郭锐阳; 于天宇; 王广洲; 周星颖
Original assignee: Harbin Institute of Technology
Current assignee: Harbin Institute of Technology
Priority date: 2022-01-27
Filing date: 2022-01-27
Publication date: 2023-08-18
Anticipated expiration: 2042-01-27
Also published as: CN114453641A

Abstract

A six-axis linkage machine tool weak electric control system, a six-axis linkage machine tool and a milling method relate to the field of micro-milling of tiny components and are used for solving the defects that milling of thin-wall spherical shell tiny components cannot be completed by the processing method in the prior art and a corresponding control system is lacked. The six-axis linkage machine tool is provided with a detachable milling tool shaft and provides a corresponding six-axis linkage machine tool weak electric control system. The method comprises a tool setting step, a first hemispherical crown processing step, a turning clamping step and a second hemispherical crown processing step. The tool setting step is used for positioning the milling cutter to an accurate position through an image acquisition and analysis technology. The first hemispherical crown processing step is used for processing partial areas of the thin-wall spherical shell. The turning clamping step is used for adjusting the position of the spherical shell and adjusting the rest unprocessed area to a position where processing can be performed. The second hemispherical crown machining step is used for machining the remaining area. The invention is used for micro milling of thin-wall spherical shell micro-components.

Description

Six-axis linkage machine tool weak electricity control system, six-axis linkage machine tool and milling method

Technical Field

The invention relates to the field of micro-milling of micro-components, in particular to a six-axis linkage machine tool weak electric control system for micro-milling of thin-wall spherical shell micro-components, a six-axis linkage machine tool and a milling method.

Background

The world is now increasingly demanding of various sophisticated, miniaturized, integrated, and tiny components. As a core device of many precise equipment, the manufacturing realization property and the processing precision of complex micro components directly affect the service performance of the equipment, and a specific ultra-precise processing technology is required to be adopted to meet the corresponding processing requirement of a characteristic microstructure. For example, in the field of energy exploration, thin-wall spherical shell micro-components with the diameter of 1-5 mm and the shell thickness of 20-120 mu m are widely applied, tens to hundreds of micro-pit structures with the longitudinal dimension of 0.5-20 mu m and the transverse dimension of 50-200 mu m are required to be processed on the whole surface, a special ultra-precise five-axis machine tool and a milling tool shaft are required to be equipped, and the high processing precision with the contour error of better than 0.3 mu m and the surface roughness Ra of better than 20nm can be achieved through multi-axis linkage control. The ultra-precise five-axis and milling tool axis linkage machine tool is equipment with the greatest difficulty and the greatest control axis number in the ultra-precise machining process, and the manufacturing precision and the service performance of the equipment directly influence the machining precision and the surface quality of a workpiece. Factors that affect the performance of a machine tool include manufacturing errors in machine tool components, installation accuracy, operating environment, errors in control systems, and the like. As an information input end of a man-machine interaction mechanism, a weak current control system and a weak current control device control the movement of each shaft of a machine tool, monitor the whole processing process, are important component parts of an ultra-precise five-shaft linkage machine tool, and the control performance directly influences the processing process effect of the ultra-precise machine tool of a five-shaft and milling tool shaft. Therefore, the construction and optimization of the weak current control system and the weak current control device special for the ultra-fine five-axis and milling tool axis linkage machine tool for micro milling of the thin-wall spherical shell micro-components have extremely important significance for improving the machining performance of the machine tool, optimizing the surface quality of a workpiece and expanding the application of the machine tool.

The weak current control system is generally composed of a direct current circuit or a part of low-voltage alternating current circuit, and covers a video circuit, an audio circuit, a communication circuit, an information feedback circuit and the like, and the direct current voltage is generally within 36V. Signal input of household cameras, telephones, computers, projectors and the like belong to weak current control equipment. In industry, the weak current control system of the ultra-precise multi-axis linkage machine tool mainly refers to the whole operation control system such as a machine tool control cabinet body, an operation control module on a control operation panel and the like, mainly covers button/knob operation on the control operation panel, program input of an industrial personal computer, plc instruction conversion, driver driving, image information acquisition and the like, and the control form and the diversity of the weak current control system directly determine the function realization property and the diversity of the ultra-precise multi-axis linkage machine tool. The existing weak current control system and device of the machine tool are single in control form, poor in system flexibility, few in repeated read-write times and poor in system flexibility, cannot realize accurate tool setting control under the constraint of a micro-space scale, monitoring of vacuum adsorption conversion during turning and clamping, and omnibearing monitoring and weak in control function in the machining process, can only realize simple motion control of a single shaft or multiple shafts, is complex in structure, low in control and machining precision, cannot meet the requirement of high-precision machining of the micro-components of the thin-wall spherical shell under the constraint of the micro-space scale, and urgent needs to develop and design a weak current control system and device special for an ultra-precision five-shaft and milling tool shaft linkage machine tool for the micro-milling of the micro-components of the thin-wall spherical shell so as to realize high-precision micro-milling of the full-surface micro-pit structure of the micro-components of the thin-wall spherical shell under the constraint of the micro-space scale and fill the technical blank.

Disclosure of Invention

The invention aims to solve the technical problems that:

the invention provides a six-axis linkage machine tool weak electric control system, a six-axis linkage machine tool and a milling method, which are used for solving the defects that the milling of thin-wall spherical shell micro-components cannot be completed by the processing method in the prior art and the corresponding control system is lacked, and further realizing the high-precision micro milling of the full-surface micro-pit structure of the thin-wall spherical shell micro-components under the constraint of micro-space scale.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the technical scheme is as follows: the weak current control system of the six-axis linkage machine tool special for micro-milling of the thin-wall spherical shell micro-components is used for controlling the X-axis movement unit, the Y-axis movement unit and the movement parts on the Z-axis movement unit on the ultra-precise six-axis linkage machine tool special for micro-milling of the thin-wall spherical shell micro-components to do linear reciprocating movement, and the B-axis turntable, the C-axis rotation unit and the rotation parts on the milling tool shaft do rotary movement;

the six-axis linkage machine tool weak electricity control system comprises:

a five-axis controller (UMAC) controlled by an upper computer, and an X-axis subsystem, a Y-axis subsystem, a Z-axis subsystem, a B-axis subsystem and a C-axis subsystem which are respectively connected with the five-axis controller; the tool shaft independent control cabinet is also included;

The X-axis subsystem comprises an X-axis driver, an X-axis linear motor and an X-axis feedback grating; the X-axis driver is used for driving the X-axis linear motor, the X-axis feedback grating is used for feeding back the movement position of the X-axis linear motor, and the X-axis linear motor is used for controlling the moving part on the X-axis moving unit to move back and forth;

the Y-axis subsystem comprises a Y-axis driver, a Y-axis linear motor and a Y-axis feedback grating; the Y-axis driver is used for driving the Y-axis linear motor, the Y-axis feedback grating is used for feeding back the motion position of the Y-axis linear motor, and the Y-axis linear motor is used for controlling the motion part on the Y-axis motion unit to move up and down;

the Z-axis subsystem comprises a Z-axis driver, a Z-axis linear motor and a Z-axis feedback grating; the Z-axis driver is used for driving the Z-axis linear motor, the Z-axis feedback grating is used for feeding back the movement position of the Z-axis linear motor, and the Z-axis linear motor is used for controlling the moving part on the Z-axis moving unit to move left and right;

the B-axis subsystem comprises a B-axis driver, a B-axis rotary motor and a B-axis feedback grating; the B-axis driver is used for driving the B-axis rotary motor, the B-axis feedback grating is used for feeding back the motion position of the B-axis rotary motor, and the B-axis rotary motor is used for controlling the rotary part of the B-axis rotary table to perform rotary motion;

The C-axis subsystem comprises a B-axis driver, a C-axis rotary motor and a C-axis feedback grating; the C-axis driver is used for driving the C-axis rotary motor, the C-axis feedback grating is used for feeding back the movement position of the C-axis rotary motor, and the C-axis rotary motor is used for controlling the rotary part of the C-axis rotary unit to perform rotary movement;

the independent tool shaft control cabinet is used for controlling the start, stop and rotation speed of the milling tool shaft, the independent tool shaft control cabinet sends an instruction to a controller in the independent tool shaft control cabinet through a panel of the independent tool shaft control cabinet, and the controller sends an instruction to a driver in the independent tool shaft control cabinet, so that the start, stop and rotation speed of the milling tool shaft are controlled.

Further, the system also comprises a microscopic imaging system connected with the upper computer, wherein the microscopic imaging system comprises a tool setting subsystem and an image acquisition subsystem.

Further, the tool setting subsystem is used for realizing monitoring of primary clamping tool setting and secondary clamping tool setting (turning clamping), and the specific process comprises the following steps:

CCD tool setting: the workpiece-cutter contact area in the X-Z plane is monitored by a vertical CCD camera, the workpiece-cutter contact area in the X-Y plane is monitored by a horizontal CCD camera, and accurate tool setting under the constraint of micro-space scale can be realized by image processing and multi-axis linkage, and the specific operation steps are as follows:

Step (1): calibrating a horizontal CCD camera and a vertical CCD camera to respectively acquire a horizontal conversion relation and a vertical conversion relation between a pixel coordinate system and a machine tool coordinate system;

step (2): acquiring an image of a cutter-workpiece contact area in an X-Z plane through a vertical CCD camera, and acquiring an image of a cutter-workpiece contact area in an X-Y plane through a horizontal CCD;

step (3): sequentially carrying out gray scale treatment and image segmentation treatment on the X-Z plane image and the X-Y plane image obtained in the step (2), and separating the thin-wall spherical shell micro-component or the ball end mill from other image backgrounds;

step (4): adopting a classical Hough transformation method, and performing iterative computation according to arc contour points to respectively obtain pixel coordinates of the spherical center position of the thin-wall spherical shell type micro-component and the spherical center position of the ball end milling cutter in an X-Z plane, and pixel coordinates of the spherical center position of the thin-wall spherical shell type micro-component and the spherical center position of the ball end milling cutter in an X-Y plane;

step (5): according to the horizontal conversion relation of the step (1), converting the pixel coordinates obtained in the step (4) to obtain the actual positions of the sphere center of the thin-wall spherical shell type micro component and the sphere center of the ball end milling cutter in the X-Y plane;

step (6): according to the vertical conversion relation of the step (1), converting the pixel coordinates obtained in the step (4) to obtain the actual positions of the sphere center of the thin-wall spherical shell type micro component and the sphere center of the ball end milling cutter in the X-Z plane;

Step (7): according to the actual position deviation of the thin-wall spherical shell micro component and the ball center of the ball end mill obtained in the step (5) and (6), the precise tool setting under the constraint of the micro-space scale is realized through program control X, Y, Z linkage;

and (3) turning around, clamping and monitoring: during turning and secondary clamping, the contact area between the thin-wall spherical shell type micro component and the vacuum adsorption clamp needs to be monitored in real time through a vertical CCD, and the specific operation steps are as follows:

step (1): in the process of carrying out secondary turning clamping, a software control system calls a vertical CCD imaging system to carry out microscopic observation on a contact area of the workpiece and the vacuum adsorption clamp;

step (2): calibrating the vertical CCD camera to obtain a conversion relation between pixel coordinates and machine tool coordinates;

step (3): acquiring an image of a contact area of the workpiece and the vacuum adsorption clamp by a vertical CCD camera;

step (4): performing gray level processing and image segmentation processing on the image obtained in the step (3), and separating the thin-wall spherical shell micro-component or the ball end mill from other image backgrounds;

step (5): adopting a classical Hough transformation method, and respectively obtaining pixel coordinates of the sphere center position of the thin-wall spherical shell type micro component in the X-Z plane and pixel coordinates of the midpoint of the head adsorption area of the turning clamping vacuum adsorption clamp according to the iterative computation of the arc contour points;

Step (6): according to the horizontal conversion relation of the step (2), converting the pixel coordinates obtained in the step (5) to obtain the actual position of the midpoint of the head absorption area of the vacuum absorption clamp for turning around and clamping the spherical center of the thin-wall spherical shell type micro component in the X-Z plane;

step (7): and the Z axis is controlled to move by a corresponding distance, so that the vacuum adsorption is monitored during turning and clamping.

Further, the image acquisition subsystem is used for acquiring the surface micro-pit image in the micro-milling process of the thin-wall spherical shell micro-component in real time so as to acquire the surface morphology of the thin-wall spherical shell micro-component, and the specific process comprises the following steps:

characteristic microstructure capture: after turning and clamping, the last micro-pit structure and the coordinates thereof during primary clamping and processing are required to be captured and identified and recorded as reference coordinates to be used as the reference of the coordinates of the primary micro-pits of the secondary turning and clamping, and the specific operation flow is as follows:

step (1): calibrating the vertical CCD camera to obtain a conversion relation between pixel coordinates and machine tool coordinates;

step (2): controlling the workpiece C-axis to rotate at a low speed, and observing the surface of the thin-wall spherical shell type micro component through a vertical CCD camera;

step (3): when the last micro-pit structure appears in the visual field during the primary clamping processing, the C-axis of the air-float workpiece stops rotating, and a vertical CCD camera is used for photographing to obtain the micro-pit image of the surface of the thin-wall spherical shell type micro-component at the moment;

Step (4): carrying out gray level processing and image segmentation processing on the image obtained in the step (3), and separating the thin-wall spherical shell micro-component and the last micro-pit structure clamped for the first time from other image backgrounds;

step (5): adopting a classical Hough transformation method, and obtaining the pixel coordinates of the last micro-pit structural point of the primary clamping of the thin-wall spherical shell micro-component according to the iterative calculation of the arc contour points;

step (6): according to the horizontal conversion relation of the step (1), converting the pixel coordinates obtained in the step (5) to obtain the actual position of the last micro-pit structure during the primary clamping processing, and completing capturing and identifying the characteristic micro-pit structure;

monitoring the processing process: the image acquisition-processing process monitoring microscopic imaging system carries out omnibearing real-time monitoring on the state of a processing area, the appearance of a workpiece, the abrasion of a cutter and the like by a high-resolution CCD camera, and cooperatively realizes the high-precision processing of the surface micro-pit structure of the thin-wall spherical shell type micro-component, and the specific operation steps are as follows:

step (1): the microscopic amplification function of the high-resolution CCD camera is utilized, and the workpiece-cutter contact area in the X-Z plane is monitored by the vertical CCD camera, so that the morphology of the workpiece, the abrasion of the cutter and the like can be monitored in real time;

Step (2): by utilizing the microscopic amplification function of the high-resolution CCD camera, the workpiece-cutter contact area in the X-Y plane is monitored by the horizontal CCD camera, so that the morphology of the workpiece and the abrasion of the cutter can be monitored in real time.

The second technical scheme is as follows: a special super-precision six-axis linkage machine tool for micro-milling of thin-wall spherical shell micro-components comprises: the weak current control system of the six-axis linkage machine tool further comprises a machine body, an X-axis movement unit, a Y-axis movement unit, a C-axis rotation unit, a primary clamping system, a vertical CCD (charge coupled device) camera, a ball end mill, a milling tool shaft, a turning clamping system, a B-axis turntable, a Z-axis movement unit and a horizontal CCD camera; the X-axis movement unit and the Z-axis movement unit are mutually vertical and horizontally arranged on the lathe bed; the Y-axis motion unit is arranged on the X-axis motion unit; the C-axis rotary unit controlled by the feedback of the circular grating is arranged in the middle of the Y-axis motion unit carriage and can move up and down; the primary clamping system is arranged on the C-axis rotation unit, and the tail end of the primary clamping system is used for adsorbing a hemispherical surface of a thin-wall spherical shell type micro component to be processed; the horizontal CCD camera is arranged on a transition plate on a B-axis turntable on the Z-axis motion unit through a first high-precision two-dimensional micro-displacement platform, and the lens axis of the CCD camera points to the center of a ball of the ball-end milling cutter; the vertical CCD camera is arranged on a transition plate of the Y-axis motion unit through a second high-precision two-dimensional micro-displacement platform; the turning clamping system is arranged on the B-axis turntable and can be arranged opposite to the primary clamping system, and is used for adsorbing the other half sphere of the thin-wall spherical shell type micro component, a ball end milling cutter for processing a plurality of micro pits on the surface of the thin-wall spherical shell type micro component is arranged on the end of a rotor of a milling tool shaft, and a stator of the milling tool shaft is detachably arranged on the B-axis turntable through a shaft bracket; the angle between the corresponding axis of the rotor of the milling tool shaft and the XZ horizontal plane is 10-15 degrees; the Z-axis moving unit moves along the direction of the organ cover so as to drive the B-axis turntable on the Z-axis moving unit to move together, and the Y-axis moving unit and the primary clamping system above the X-axis moving unit move along the direction of the organ cover. The six axes refer to the degrees of freedom of movement in six directions: the corresponding X axis of the X axis moving unit 2 (X axis moving platform), the corresponding Y axis of the Y axis moving unit 3 (Y axis moving platform), the corresponding Z axis of the Z axis moving unit 12 (Z axis moving platform), the corresponding rotation direction of the B axis turntable 11 (B axis moving platform), the corresponding rotation direction of the C axis rotating unit (also called air-float workpiece C axis or C axis moving platform), the rotation direction of the rotor of the milling tool shaft.

The technical scheme is as follows: the method is realized based on the ultra-precise six-axis linkage machine tool special for micro milling of the thin-wall spherical shell micro component, and comprises a tool setting step, a first hemispherical crown machining step, a turning clamping step and a second hemispherical crown machining step, wherein the tool setting step comprises the following steps of:

the tool setting step comprises the following steps:

calibrating a horizontal CCD camera and a vertical CCD camera to respectively acquire a horizontal conversion relation and a vertical conversion relation between a pixel coordinate system and a machine tool coordinate system;

acquiring an image of a cutter-workpiece contact area in an X-Z plane through a vertical CCD camera, and acquiring an image of a cutter-workpiece contact area in an X-Y plane through a horizontal CCD;

sequentially carrying out gray scale treatment on the X-Z plane inner cutter-workpiece contact area image and the X-Y plane inner cutter-workpiece contact area image, and carrying out image segmentation treatment to separate a thin-wall spherical shell type micro component or a ball end mill from other image backgrounds;

adopting a classical Hough transformation method, and performing iterative computation according to arc contour points to respectively obtain pixel coordinates of the spherical center position of the thin-wall spherical shell type micro-component and the spherical center position of the ball end milling cutter in an X-Z plane, and pixel coordinates of the spherical center position of the thin-wall spherical shell type micro-component and the spherical center position of the ball end milling cutter in an X-Y plane;

According to the horizontal conversion relation, the actual positions of the centers of the thin-wall spherical shell micro-members and the ball end mill in the X-Y plane can be obtained by converting the pixel coordinates of the positions of the centers of the thin-wall spherical shell micro-members in the X-Y plane and the pixel coordinates of the positions of the centers of the ball end mill in the ball end mill;

according to the vertical conversion relation, the actual positions of the centers of the thin-wall spherical shell micro-members and the ball end mill in the X-Z plane can be obtained by converting the pixel coordinates of the positions of the centers of the thin-wall spherical shell micro-members in the X-Z plane and the pixel coordinates of the positions of the centers of the ball end mill in the ball end mill;

according to the actual positions of the centers of the thin-wall spherical shell micro-components and the ball head milling cutter in the X-Y, X-Z plane, the linkage is controlled X, Y, Z by a program to realize tool setting;

the first hemispherical crown processing step comprises the following steps:

controlling the rotating platform of the B shaft to rotate forward by alpha;

controlling X, Z shaft linkage to enable the ball end mill to radially feed the thin-wall ball shell type micro-members to a set machining depth;

according to the planned program processing path, the C axis of the air-float workpiece rotates by beta ₁ The angle is changed to the other longitude surface, and the step of controlling the B-axis turntable to rotate forward alpha is returned to finish the processing of the next micro-pit structure;

the turning clamping step comprises the following steps:

Control the moving distance X of the X-axis moving unit ₁ The method comprises the steps of carrying out a first treatment on the surface of the The axis of the vacuum adsorption clamp of the turning clamping system and the axis of the vacuum adsorption clamp of the primary clamping system are in the same plane;

control Y-axis motion unit to move Y ₁ The axis of the vacuum adsorption fixture of the turning clamping system is coaxial with the axis of the vacuum adsorption fixture of the primary clamping system;

controlling Z-axis movement distance Z ₁ The method comprises the steps of carrying out a first treatment on the surface of the Observing the contact area between the vacuum adsorption clamp and the thin-wall spherical shell micro component through a vertical CCD camera, so that the vacuum adsorption clamp of the turning clamping system is tightly contacted with the thin-wall spherical shell micro component;

applying vacuum negative pressure to the vacuum adsorption clamp of the head turning clamping system, releasing the vacuum adsorption clamp negative pressure of the primary clamping system, transferring the thin-wall spherical shell micro-components to the vacuum adsorption clamp of the head turning clamping system, and realizing secondary clamping of the thin-wall spherical shell micro-components;

the zero point quick-change system in the turning clamping system and the vacuum adsorption clamp with the tail end connected with the thin-wall spherical shell type micro component are disassembled and connected to the C shaft of the air-float workpiece, so that the turning secondary clamping of the thin-wall spherical shell type micro component is realized;

the second hemispherical crown processing step comprises the following steps:

positioning the last micro-pit structure completed in the first hemispherical crown processing step through a vertical CCD camera, and controlling the workpiece to enable the micro-pit structure to be positioned in an X-Z plane where the C-axis of the air-float workpiece is positioned;

Controlling X, Z shaft linkage to enable the ball end mill to radially feed a set machining depth along the micro component of the thin-wall ball shell;

control the C-axis rotation beta of the air-float workpiece ₂ And (5) finishing the processing of the next micro-pit structure from the corner to the other longitudinal surface.

The invention has the following beneficial technical effects:

(1) The invention integrates five-axis linkage control, a high-speed milling axis independent control module and a double high-resolution CCD microscopic imaging system into a whole, is a weak current control system special for a five-axis linkage machine tool for micro milling of thin-wall spherical shell micro-components, and can realize weak current control of the five-axis linkage machine tool for high-precision machining of thin-wall spherical shell micro-components with the diameter of 1-5 mm, the shell thickness of 20-120 mu m, which are uniformly distributed on the whole surface of tens to hundreds of thin-wall spherical shell micro-components, the longitudinal dimension of 0.5-20 mu m and the transverse dimension of 50-200 mu m;

(2) The invention concentrates the panel operation module, the instruction control module, the program driving module and the element movement module into a cabinet body device, has compact structure, adopts an IPC+NC control mode, takes an industrial personal computer as an upper computer of UMAC to send a command to UMAC, processes related commands and acts on an end execution element through a driver, the execution element starts to make corresponding actions, and finally the execution element feeds back the actual position to UMAC through a grating, the UMAC completes corresponding functions and returns the result to the industrial personal computer to form closed loop compensation, further improves the processing precision, and the PLC and a system control program can repeatedly read and write, has various control modes, good system flexibility and good flexibility;

(3) The invention adopts the self-resetting normally open click button, and the normally closed emergency stop button is rotated to reset, thereby being convenient to operate, effectively ensuring the processing safety and achieving higher weak current control performance and processing precision;

(4) The milling shaft of the high-speed air bearing is independently controlled by the independent control panel, the micro cutter is clamped by the HSKE chuck to realize the processing of the micro-scale and small-scale structure, the motion error is less than 30nm, the rotating speed can be adjusted according to the actual working condition requirement, and the high-rotating speed and high-precision processing requirement of the micro milling processing of the surface microstructure of the thin-wall spherical shell type micro component is met;

(5) The microscopic imaging system comprises a tool setting microscopic imaging system and an image acquisition-processing process monitoring microscopic imaging system, both of which are composed of 2620 ten-thousand-pixel high-resolution CCD cameras, and can realize accurate tool setting under the constraint of micro-space scale, monitoring of vacuum adsorption conversion during turning and clamping and omnibearing monitoring of the processing process;

(6) The method has certain universality, after the double-high-resolution CCD microscopic imaging system is dismantled, the conventional control of a common five-axis machine tool can be realized, the milling shaft can be independently controlled by the high-speed air bearing, and the weak current control of the conventional lathe machining can be realized by replacing the turning tool and the accessories thereof.

Other features of the present invention and its advantages will become apparent from the following detailed description of exemplary embodiments of the invention, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Fig. 1 is a structural diagram of an ultra-precise six-axis linkage machine tool special for micro-milling of thin-wall spherical shell micro-components, according to the invention (fig. 1 is an overall structural assembly diagram of an ultra-precise five-axis and milling tool axis linkage machine tool for micro-milling of thin-wall spherical shell micro-components, provided by the invention);

FIG. 2 is a top view of the vertical CCD camera 6 of FIG. 1 with the vertical CCD camera removed;

FIG. 3 is a functional block diagram of a weak current control system according to one embodiment of the present invention;

FIG. 4 is a flow chart of a weak current control system according to one embodiment of the invention;

FIG. 5 is a schematic diagram of the components of a weak current control system according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of an operator panel layout (milling axis control panel) according to one embodiment of the present invention;

FIG. 7 is a flow chart of a control of a PLC driver according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of the precise tool setting in one embodiment of the invention;

Fig. 9 is a schematic diagram of a turn-around clamp according to an embodiment of the present invention.

Detailed Description

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise.

The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of exemplary embodiments may have different values.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.

< embodiment one: weak current control System)

The present embodiment provides a weak electric control system of a five-axis and milling tool axis linkage machine tool, as shown in fig. 3, for executing the micro milling method of the thin-wall spherical shell type micro-component according to the first embodiment, the weak electric control system of the five-axis and milling tool axis linkage machine tool includes: the device comprises a controller, and an X-axis subsystem, a Y-axis subsystem, a Z-axis subsystem, a B-axis subsystem, a C-axis subsystem and a tool axis subsystem which are respectively connected with the controller; the X-axis subsystem comprises an X-axis driver, an X-axis linear motor, an X-axis feedback grating and an X-axis motion platform; the X-axis driver is used for driving the X-axis linear motor, the X-axis feedback grating is used for feeding back the movement position of the X-axis linear motor, and the X-axis movement platform is used for driving the X-axis linear motor to move on the platform; the Y-axis subsystem comprises an X-axis driver, a Y-axis linear motor, a Y-axis feedback grating and a Y-axis motion platform; the Y-axis driver is used for driving the Y-axis linear motor, the Y-axis feedback grating is used for feeding back the motion position of the Y-axis linear motor, and the Y-axis motion platform is used for driving the X-axis linear motor to move on the platform; the Z-axis subsystem comprises an X-axis driver, a Z-axis linear motor, a Z-axis feedback grating and a Z-axis motion platform; the Z-axis driver is used for driving the Z-axis linear motor, the Z-axis feedback grating is used for feeding back the motion position of the Z-axis linear motor, and the Z-axis motion platform is used for driving the Z-axis linear motor to move on the platform; the B-axis subsystem comprises a B-axis driver, a B-axis rotary motor, a B-axis feedback grating and a B-axis motion platform; the B-axis driver is used for driving the B-axis rotary motor, the B-axis feedback grating is used for feeding back the motion position of the B-axis rotary motor, and the B-axis rotary motor is used for controlling the rotary part of the B-axis rotary table to perform rotary motion; the C-axis subsystem comprises a B-axis driver, a C-axis rotary motor, a C-axis feedback grating and a C-axis motion platform; the C-axis driver is used for driving the C-axis rotary motor, the C-axis feedback grating is used for feeding back the movement position of the C-axis rotary motor, and the C-axis rotary motor is used for controlling the rotary part of the C-axis rotary unit to perform rotary movement; the tool shaft subsystem comprises a control cabinet and a tool shaft, wherein the control cabinet is used for controlling the tool shaft and is controlled by the controller.

Further, the weak current control system further comprises an upper computer connected with the controller and a microscopic imaging system connected with the upper computer, wherein the microscopic imaging system further comprises a tool setting subsystem and an image acquisition subsystem.

The system inputs control instructions manually or by programs through a panel operation module, reads and converts the control instructions through a plc control and system program control module, controls a program driving module, sends instructions to a driver through a controller, and drives a X, Y, Z, B, C shaft and a milling tool shaft to move by the driver, so that the start-stop motion control of a main shaft, the controller, a motion system and the like of the ultra-precise five-shaft machine tool, the precise tool setting under the constraint of micro-space scale, the monitoring of vacuum adsorption conversion during turning and clamping and the omnibearing monitoring of the machining process are realized. The invention integrates the operation on-off of the ultra-precise five-axis linkage machine tool, the automatic control of weak electric hand, the independent control of the high-speed milling tool shaft and the double-high-resolution CCD microscopic imaging system, realizes the motion control of each shaft and the omnibearing monitoring of the processing process through plc control and program drive, and the plc and system control program can be read and written repeatedly, thereby greatly increasing the flexibility of the system, and being particularly suitable for the weak electric control of the ultra-precise five-axis linkage machine tool special for the micro milling of the surface micro pit structure of the thin-wall spherical shell micro-component.

< embodiment two: turning and milling combined five-axis linkage machine tool

The embodiment provides a super-precision six-axis linkage machine tool special for micro-milling of thin-wall spherical shell micro-components, which comprises the six-axis linkage machine tool weak current control system, and further comprises a machine tool body 1, an X-axis motion unit 2, a Y-axis motion unit 3, a C-axis rotation unit 4, a primary clamping system 5, a vertical CCD camera 6, a ball end mill 8, a milling tool shaft 9, a turning clamping system 10, a B-axis turntable 11, a Z-axis motion unit 12 and a horizontal CCD camera 13; the X-axis movement unit 2 and the Z-axis movement unit 12 are mutually vertical and horizontally arranged on the lathe bed 1; the Y-axis moving unit 3 is arranged on the X-axis moving unit 2; the C-axis rotary unit 4 controlled by the circular grating feedback is arranged in the middle of the carriage of the Y-axis motion unit 3 and can move up and down; the primary clamping system 5 is arranged on the C-axis rotary unit 4, and the tail end of the primary clamping system 5 is used for adsorbing a hemispherical surface of a thin-wall spherical shell type micro component 7 to be processed; the horizontal CCD camera 13 is arranged on a transition plate on the B-axis turntable 11 on the Z-axis motion unit 12 through a first high-precision two-dimensional micro-displacement platform, and the lens axis of the CCD camera points to the center of the ball-end milling cutter; the vertical CCD camera 6 is arranged on a transition plate of the Y-axis motion unit 3 through a second high-precision two-dimensional micro-displacement platform; the turning clamping system 10 is arranged on the B-axis turntable 11 and can be arranged opposite to the primary clamping system 5, and is used for adsorbing the other half sphere of the thin-wall spherical shell type micro-component 7, a ball end milling cutter 8 for processing a plurality of micro pits on the surface of the thin-wall spherical shell type micro-component 7 is arranged on the rotor end of the milling tool shaft 9, and a stator of the milling tool shaft 9 is detachably arranged on the B-axis turntable 11 through a shaft bracket; the angle between the corresponding axis of the rotor of the milling tool shaft 9 and the XZ horizontal plane is 10-15 degrees; the Z-axis moving unit 12 moves along the direction of the organ cover thereof to drive the B-axis turntable 11 thereon to move together, and the Y-axis moving unit 3 and the primary clamping system 5 above the X-axis moving unit 2 move along the direction of the organ cover thereof. The six axes refer to the degrees of freedom of movement in six directions: the corresponding X axis of the X axis moving unit 2 (X axis moving platform), the corresponding Y axis of the Y axis moving unit 3 (Y axis moving platform), the corresponding Z axis of the Z axis moving unit 12 (Z axis moving platform), the corresponding rotation direction of the B axis turntable 11 (B axis moving platform), the corresponding rotation direction of the C axis rotating unit 4 (also called as air-float workpiece C axis or C axis moving platform), the rotation direction of the rotor of the milling tool shaft 9.

The X-axis movement unit 2 and the Z-axis movement unit 12 are mutually perpendicular to each other and are arranged on the lathe bed 1; the Y-axis moving unit 3 is arranged on the X-axis moving unit 2; the C-axis 4 of the air-float workpiece is controlled by the feedback of a circular grating and is arranged in the middle of the carriage of the Y-axis motion unit 3; the primary clamping system 5 is connected to the C shaft 4 of the air-float workpiece, and the tail end of the primary clamping system 5 is connected with a thin-wall spherical shell micro component 7 to be processed; the horizontal CCD camera 13 is fixed on a transition plate on the B-axis turntable 11 through a first displacement platform, and the axis of a lens points to the center of a ball of the ball-end milling cutter; the vertical CCD camera 6 is fixed on a transition plate of the Y-axis motion unit 3 through a second displacement platform, and the transition plate of the Y-axis motion unit 3 is connected to a carriage of the Y-axis motion unit 3 and can move along with the Y-axis motion unit 3; the five-axis linkage machine tool is used for realizing the micro milling processing method of the thin-wall spherical shell type micro component in the first embodiment. A significant technical improvement of this embodiment is that the ball end mill 8 and the milling tool shaft 9 are of a detachable structure, and can be flexibly mounted on a general-purpose processing machine tool, so that the machine tool has the capability of processing thin-wall spherical shell type micro members.

Furthermore, the milling tool shaft 9 can be a high-speed air bearing tool spindle of ASD-080H25 type manufactured by Levicron corporation of Germany, the rotating speed range is 0-80000r/min, the axial rigidity is better than 45N/mu m, the radial rigidity is better than 25N/mu m, and the movement error is smaller than 30nm;

The tool shaft independent control cabinet can be an ASD-080H25 main shaft special independent control cabinet manufactured by Levicron corporation of Germany; the control panel of the independent control cabinet adopts a KTP400 Basic model operation panel manufactured by Siemens of Germany, and the resolution is 480x 272;

the independent tool shaft control cabinet sends an instruction to a controller in the independent tool shaft control cabinet through a panel of the independent tool shaft control cabinet, and the controller sends an instruction to a driver in the independent tool shaft control cabinet, so that the start and stop and the rotating speed of the milling tool shaft 9 are controlled.

< embodiment three: milling method >

The present invention is based on a processing apparatus as shown in CN113695646a, and this embodiment is a method of processing using the apparatus. The method of the embodiment mainly comprises a tool setting step, a first hemispherical crown processing step, a turning clamping step and a second hemispherical crown processing step. The tool setting step is used for positioning the milling cutter to an accurate position through an image acquisition and analysis technology. The first hemispherical crown machining step is used for machining a machinable area of the thin-walled spherical shell, and the rest area cannot be machined due to the position of the spherical shell. The turning clamping step is used for adjusting the position of the spherical shell and adjusting the rest unprocessed area to a position where processing can be performed. The second hemispherical crown machining step is used for machining the remaining area.

An example of the processing apparatus according to the present embodiment is shown in fig. 1 and 2, and includes: the device comprises a lathe bed 1, an X-axis moving unit 2, a Y-axis moving unit 3, an air-float workpiece C-axis 4, a primary clamping system 5, a vertical CCD camera 6, a thin-wall spherical shell micro-component 7, a ball end mill 8, a milling tool shaft 9, a turning clamping system 10, a B-axis turntable 11, a Z-axis moving unit 12 and a horizontal CCD camera 13. The horizontal X/Z axis movement units are mutually and vertically arranged on the bed body and driven by the hydrostatic guideway linear motor; the vertical Y-axis movement unit is arranged on the X-axis movement unit and driven by the hydrostatic guideway linear motor; the C-axis of the air-float workpiece adopts an air hydrostatic bearing, is controlled by the feedback of a circular grating and is arranged in the middle of the dragging plate of the Y-axis motion unit; the primary clamping system is connected to the C shaft of the air-float workpiece through an inner hexagon screw, and the tail end of the primary clamping system is connected with a workpiece to be processed, namely a thin-wall spherical shell type micro component; the horizontal CCD camera is fixed on a transition plate on the B-axis rotary table through a high-precision two-dimensional micro-displacement platform, and the axis of the lens points to the center of the ball-end milling cutter; the vertical CCD camera is fixed on a Y-axis motion unit transition plate through a high-precision micro-displacement platform, and the Y-axis transition plate is connected on a Y-axis carriage through an inner hexagon screw and can move along with the Y-axis motion unit.

The tool setting step SA comprises the following steps:

SA-1: and calibrating the horizontal CCD camera and the vertical CCD camera to respectively acquire a horizontal conversion relation and a vertical conversion relation between the pixel coordinate system and the machine tool coordinate system.

SA-2: and acquiring an image of the contact area of the cutter and the workpiece in the X-Z plane through a vertical CCD camera, and acquiring an image of the contact area of the cutter and the workpiece in the X-Y plane through a horizontal CCD.

SA-3: and (3) sequentially carrying out gray scale treatment on the image of the cutter-workpiece contact area in the X-Z plane and the image of the cutter-workpiece contact area in the X-Y plane, and carrying out image segmentation treatment to separate the thin-wall spherical shell micro-members or the ball end mill from other image backgrounds.

SA-4: and (3) adopting a classical Hough transformation method, and respectively obtaining the pixel coordinates of the ball center position of the thin-wall ball shell type micro-component and the pixel coordinates of the ball center position of the ball end mill in the X-Z plane, and the pixel coordinates of the ball center position of the thin-wall ball shell type micro-component and the pixel coordinates of the ball center position of the ball end mill in the X-Y plane according to the iterative computation of the arc contour points.

SA-5: according to the horizontal conversion relation, the actual positions of the centers of the thin-wall spherical shell micro-components and the ball end mill in the X-Y plane can be obtained by converting the pixel coordinates of the positions of the centers of the thin-wall spherical shell micro-components and the pixel coordinates of the positions of the centers of the ball end mill in the X-Y plane.

SA-6: according to the vertical conversion relation, the actual positions of the centers of the thin-wall spherical shell micro-components and the ball end mill in the X-Z plane can be obtained by converting the pixel coordinates of the positions of the centers of the thin-wall spherical shell micro-components and the pixel coordinates of the positions of the centers of the ball end mill in the X-Z plane.

SA-7 realizes tool setting by program control X, Y, Z linkage according to the actual positions of the centers of the thin-wall spherical shell micro-members and the ball center of the ball end milling cutter in the X-Y, X-Z plane.

The first hemispherical crown processing step SB includes:

SB-1: and controlling the B-axis turntable to rotate forward by alpha.

SB-2: and controlling X, Z shaft linkage to enable the ball end mill to radially feed the thin-wall ball shell type micro-component to a set machining depth.

SB-3: according to the planned program processing path, the C axis of the air-float workpiece rotates by beta ₁ And (3) returning to the step of controlling the B-axis turntable to rotate forward alpha from the angle to the other longitudinal surface, and finishing the processing of the next micro-pit structure.

The turning clamping step SC comprises the following steps:

SC-1: control the moving distance X of the X-axis moving unit ₁ The method comprises the steps of carrying out a first treatment on the surface of the The axis of the vacuum adsorption clamp of the turning clamping system and the axis of the vacuum adsorption clamp of the primary clamping system are in the same plane.

SC-2: control Y-axis motion unit to move Y ₁ The axis of the vacuum adsorption fixture of the turning clamping system is coaxial with the axis of the vacuum adsorption fixture of the primary clamping system.

SC-3: controlling Z-axis movement distance Z ₁ The method comprises the steps of carrying out a first treatment on the surface of the And observing the contact area between the vacuum adsorption clamp and the thin-wall spherical shell micro component through a vertical CCD camera, so that the vacuum adsorption clamp of the turning clamping system is tightly contacted with the thin-wall spherical shell micro component.

SC-4: and applying vacuum negative pressure to the vacuum adsorption clamp of the head adjusting clamping system, releasing the vacuum adsorption clamp negative pressure of the primary clamping system, transferring the thin-wall spherical shell micro-components to the vacuum adsorption clamp of the head adjusting clamping system, and realizing the secondary clamping of the thin-wall spherical shell micro-components.

SC-5: and disassembling the zero point quick-change system in the turning clamping system and the vacuum adsorption clamp with the tail end connected with the thin-wall spherical shell type micro component, and connecting the vacuum adsorption clamp to the C shaft of the air-float workpiece to realize the turning secondary clamping of the thin-wall spherical shell type micro component.

The second hemispherical crown processing step SD includes:

SD-1: and positioning the last micro-pit structure finished in the first hemispherical crown processing step by a vertical CCD camera, and controlling the workpiece C to enable the micro-pit structure to be positioned in an X-Z plane where the axis of the C shaft of the air-float workpiece is positioned.

SD-2: and controlling X, Z shaft linkage to enable the ball end mill to radially feed the thin-wall ball shell micro-component to a set machining depth.

SD-3: control the C-axis rotation beta of the air-float workpiece ₂ And (5) finishing the processing of the next micro-pit structure from the corner to the other longitudinal surface.

< example >

In this embodiment, the processing apparatus shown in CN113695646a is shown in fig. 1 and 2 in the structure, the corresponding weak current control system is shown in fig. 3, and the weak current control flow is shown in fig. 4. The weak current control system of the present embodiment is composed of a panel operation module, an instruction control module, a program driving module, and an element movement module, as shown in fig. 5. The panel operation module comprises an instruction input button for starting, stopping, emergency stopping, safety control and the like, a touch screen-mechanical key integrated milling shaft independent control operation panel and an industrial level display, as shown in fig. 6. When the ultra-precise five-axis and milling tool axis (collectively referred to as six axes) linkage machine tool is controlled, the on-off control of the whole control loop can be realized through a knob switch, the manual input of a control command is realized by the touch-and-release rising edge of a click button, a scram button is connected in the control loop in series in a normally closed mode, the control power supply loop can be disconnected by one key under the emergency, the movement of each axis is stopped, and the operation safety is effectively ensured. The instruction control module consists of a plc controller, an intermediate relay, a software control system and the like, establishes communication between the plc controller and an upper computer (industrial personal computer) through communication setting, realizes uploading and downloading of a plc control program through an RS232 communication port, and can be read and written repeatedly; the software control system is used for leading in the processing program of the whole surface micro-pit structure of the thin-wall spherical shell micro-component, so that the program instruction control of the processing process can be realized. The program driving module consists of an upper computer (industrial personal computer), each motion axis driver and a microscopic imaging system. And a program control instruction is input through the upper computer to control the motion axis controller to control the end execution element. The microscopic imaging system is connected with an upper computer (industrial personal computer) through a USB3.0 data interface to carry out high-speed transmission of image data. The microscopic imaging system comprises a tool setting microscopic imaging system and an image acquisition-processing process monitoring microscopic imaging system, and consists of 2620 ten-thousand-pixel high-resolution CCD cameras carried with micro-displacement platforms, so that accurate tool setting of two clamping before and after processing of the thin-wall spherical shell type micro-component full-surface micro-pit structure under the constraint of a micro-space scale and omnibearing monitoring of the processing process can be realized. The element movement module comprises a X, Y, Z shaft movement unit, an air bearing workpiece main shaft, a hydraulic rotary table and a high-speed air bearing milling tool shaft. The control instruction is input through the instruction control module, so that the on-off control of the driver is realized, the instruction is further sent by the upper computer, and the driver drives the tail end executing element to move.

When the ultra-fine five-axis and milling tool axis linkage special weak current control system based on micro-milling of the micro-surface pit structure of the thin-wall spherical shell micro-component works, a PLC control program is written into a PLC controller through an RS232 communication port, a panel operation module inputs a control instruction manually or by a program through an upper computer (an industrial personal computer), the control instruction is processed through a UMAC motion controller, the control program is driven by an I/O program conversion of the PLC and a system program, a control program driving module realizes driving control of an element motion module through each axis driver, an executive element feeds back the actual position of each axis motion to the UMAC controller through a high-precision feedback grating, closed-loop compensation is performed, and the processing precision is further improved, as shown in figure 6. The high-speed air bearing milling tool shaft touch screen-mechanical key integrated milling shaft independent control operation panel is independently controlled, the micro-tool can be clamped by the HSKE chuck to process the micro-scale and small-scale component, the movement error is less than 30nm, the rotating speed can be adjusted according to the actual working condition requirement, and the high-rotating-speed and high-precision processing requirement of a workpiece is met.

The specific control flow of this embodiment is as follows:

step 1-program loading of instructions:

starting a circuit main power supply, switching on a PLC logic controller power supply module and an ultra-precise five-axis and milling tool axis linkage machine tool power supply module, and writing a weak current control program into the PLC logic controller through an RS232 communication port by a PC; the five-axis and milling tool axis linkage control instruction is imported/manually input through the panel operation module, so that weak current motion control of the machine tool is realized, and the specific steps are as follows:

Step 1.1: pressing a start button of a control operation panel, communicating a weak current control device with a control cabinet power supply, and connecting an upper computer (industrial personal computer) and an industrial display;

step 1.2: the X, Y, Z, B, C shaft manual control-knob switch ON the control panel is adjusted to the ON position, so that the communication of the manual control switch in the control loop is realized;

step 1.3: according to the control flow shown in fig. 4, the power supply of the independent control cabinet of the spindle, the controller, the movement shaft, the light source control and the milling shaft is sequentially pressed down to be communicated with the click button;

step 1.4: the control program is imported or manually written to send instructions to the controller according to actual control needs through the industrial display by the upper computer software control system, the controller processes related commands and drives end execution elements such as an X axis, a Y axis, a Z axis, a B axis, a C axis and the like through the driver, the milling shaft is independently controlled to start and stop through the touch screen-mechanical key integrated milling shaft, the rotating speed is adjusted through the operation panel, and high-precision machining of the full-surface micro pit structure of the thin-wall spherical shell micro component is cooperatively achieved, and a specific control flow is shown in figure 7.

Step 2-multiaxial linkage control:

the method comprises the following steps of sending an instruction to a multi-axis motion controller through an upper computer (industrial personal computer), driving each axis motion unit by a driver, realizing ultra-precise five-axis and milling tool axis (six-axis) multi-axis linkage control, and further realizing the high-precision processing requirement of the full-surface micro-pit structure of the thin-wall spherical shell type micro-component, wherein the specific steps are as follows:

Step 2.1: and clamping the workpiece and the cutter, and connecting the thin-wall spherical shell type micro component to the C shaft of the air-float workpiece through a primary clamping system. The primary clamping system comprises a vacuum adsorption clamp and a zero point quick change system. The thin-wall spherical shell type micro component is connected to the vacuum adsorption clamp under the action of vacuum negative pressure, and the vacuum adsorption clamp is connected to the reference plate of the zero point quick-change system through the socket head cap screw and can be detached together with the zero point quick-change system. The zero quick-change system is connected to the C shaft of the air-float workpiece through an inner hexagon screw; and clamping the micro-diameter ball end mill at the tail end of the milling tool shaft through the HSKE chuck.

Step 2.2: zeroing each axis of the machine tool: the upper computer software control system inputs the command G00X 0Y 0Z 0B 0C 0, drives each axis to return to the origin of coordinates, and performs preparation work before machining.

Step 2.3: tool setting and program preparation: manual tool setting is realized by program control feeding, a X, Y, Z shaft is controlled to respectively realize accurate tool setting in a horizontal plane and a vertical plane, an image of a tool-workpiece contact area in an X-Z plane is obtained through a vertical CCD, an image of a tool-workpiece contact area in an X-Y plane is obtained through a horizontal CCD, real-time coordinates of the center of a thin-wall spherical shell micro-component and the center of a ball end milling cutter are obtained through image processing, the thin-wall spherical shell micro-component is just contacted with the ball end milling cutter through X, Y, Z shaft linkage, the center of the ball is positioned in the same plane, and accurate tool setting before machining is completed, as shown in fig. 8. At this time, Z-axis moves by a distance Z ₀ Distance X of movement of X axis ₀ Distance Y of movement of Y axis ₀ . And importing a pre-written numerical control program for machining the weak hemispherical crown surface micro-pit structure of the thin-wall spherical shell micro-component, and completing the preparation work before numerical control machining.

Further, in step 2.3, the main steps of accurate tool setting of the CCD include:

step (7): according to the actual position deviation of the thin-wall spherical shell micro component and the ball center of the ball end mill obtained in the step (5) and (6), accurate tool setting under the constraint of micro-space scale is realized through program control X, Y, Z linkage.

Step 2.4: multiaxial coordinated control-initial weak hemispherical crown: loading a pre-written numerical control program for machining the weak hemispherical crown surface micro-pit structure of the thin-wall spherical shell micro-component through a software control system, running the program, and starting to machine the weak hemispherical crown surface micro-pit structure of the thin-wall spherical shell micro-component, wherein the specific control flow of each shaft is as follows:

step (1): starting a milling tool shaft through a milling shaft independent control panel, and adjusting the milling tool shaft to a required rotating speed n;

step (2): the rotation alpha of the B-axis turntable in the forward direction (clockwise in overlook) is controlled, and the X, Z-axis linkage is further controlled so that the ball end milling cutter reaches the position right above the initial micro-pit structure in the planned processing track and is recorded as an initial longitude plane;

Step (3): control X, Z shaft linkage, and radial feeding of ball end mill along thin-wall ball shell type micro-component requires machining depth a _p After feeding, X, Z is linked, and moves reversely along the radial direction of the workpiece and returns to a safe distance, so that the processing of the initial micro-pit structure is completed;

step (4): according to the planned program processing path, the C axis of the air-float workpiece rotates by beta ₁ Repeating the step (2) and the step (3) from the corner to the other longitudinal surface to finish the processing of the second micro-pit structure;

step (5): and (4) repeating the step to finish the machining of the weak hemispherical crown micro-pit structure of the thin-wall spherical shell micro-component, and after the machining is finished, executing zero return operation by the machine tool, stopping milling the tool shafts, and returning each shaft to the origin of coordinates.

Step 2.5: turning and clamping. After the processing of the initial weak hemispherical crown surface micro-pit structure of the thin-wall spherical shell micro-component is completed, turning and clamping of the thin-wall spherical shell micro-component are required to be carried out so as to realize the high-precision processing of the full surface micro-pit structure of the thin-wall spherical shell micro-component, and the specific turning and clamping method is as follows:

step (1): the turning clamping system comprises a vacuum adsorption clamp and a zero point positioning system. The instruction control module controls the X-axis movement unit to move by a distance X ₁ The axis of the vacuum adsorption clamp of the turning clamping system and the axis of the vacuum adsorption clamp of the primary clamping system are in the same plane; further control the Y-axis motion unit to move Y ₁ The axis of the vacuum adsorption fixture of the turning clamping system is coaxial with the axis of the vacuum adsorption fixture of the primary clamping system; further control of Z-axis movement distance Z ₁ The contact area of the vacuum adsorption clamp and the thin-wall spherical shell micro-component is observed through a vertical CCD, so that the vacuum adsorption clamp of the turning clamping system is tightly contacted with the thin-wall spherical shell micro-component, as shown in fig. 9.

Step (2): applying vacuum negative pressure to the vacuum adsorption clamp of the head turning clamping system, releasing the vacuum adsorption clamp negative pressure of the primary clamping system, transferring the thin-wall spherical shell micro-components to the vacuum adsorption clamp of the head turning clamping system, and realizing secondary clamping of the thin-wall spherical shell micro-components;

step (3): the zero point quick-change system in the clamping system and the vacuum adsorption fixture with the tail end connected with the thin-wall spherical shell type micro component are disassembled by utilizing the high repeated positioning precision quick-change property of the zero point quick-change system in the clamping system and are connected to the C shaft of the air-float workpiece, so that the turning secondary clamping of the thin-wall spherical shell type micro component is realized.

Step 2.6: multiaxial coordinated control-residual hemispherical crown: after turning around and clamping the thin-wall spherical shell type micro-component for the second time, processing the surface micro-pit structure of the residual hemispherical crown, wherein the specific steps are as follows:

Step (1): capturing a characteristic microstructure, controlling the workpiece C-axis to rotate at a low speed, monitoring the surface of a thin-wall spherical shell type micro component through a vertical CCD camera, capturing the last micro-pit structure processed during primary clamping, recording as a reference micro-pit, and further rotating the air-float workpiece C-axis to enable the micro-pit structure to be positioned in an X-Z plane where the axis of the air-float workpiece C-axis is positioned, and taking the micro-pit structure as a reference of initial micro-pit coordinates after secondary turning and clamping; and recording the next pit of the reference pit in the planned program as the initial pit of the turning clamping.

Step (2): starting a milling tool shaft through a milling shaft independent control panel, and adjusting the milling tool shaft to a required rotating speed n;

step (3): control the B-axis turntable to rotate forward (clockwise in overlook) by alpha ₂ Further controlling X, Z shaft linkage to enable the ball end milling cutter to reach the position right above the initial turning clamping micro-pit to be recorded as an initial longitude surface;

step (4): control X, Z shaft linkage, and radial feeding of ball end mill along thin-wall ball shell type micro-component requires machining depth a _p After feeding, X, Z is linked, and moves reversely along the radial direction of the workpiece to return to a safe distance, so that the processing of the turning clamping initial micro-pit structure is completed;

step (5): according to the planned program processing path, the C axis of the air-float workpiece rotates by beta ₂ Repeating the step (3) (4) from the corner to the other longitudinal surface to finish the processing of the second micro-pit structure;

step (6): and (5) repeating the step, finishing the machining of the surface micro-pit structure of the residual semi-spherical crown of the thin-wall spherical shell type micro-component, and after finishing the machining, executing zero return operation by the machine tool, stopping milling the tool shafts, and returning each shaft to the origin of coordinates.

Step (7): and (3) finishing the high-precision processing of the full-surface micro-pit structure of the thin-wall spherical shell type micro-component.

Step 3-microscopic imaging System monitoring:

a 2620 ten thousand high-resolution microscopic imaging system in an upper computer (industrial personal computer) collects and analyzes the image of a processing area in real time and feeds the image back to a display image display module, and a 2620 ten thousand high-resolution CCD camera observes a workpiece-cutter contact area in the cutter setting microscopic imaging system so as to realize accurate cutter setting under the constraint of a micro-space scale; the image acquisition-processing process monitoring microscopic imaging system captures the characteristic pit microstructure in real time by a high-resolution CCD camera, monitors vacuum adsorption conversion during turning and clamping, monitors the processing area state, the workpiece morphology, cutter abrasion and the like in an all-around manner in real time, and cooperatively realizes high-precision processing of the pit structure on the surface of the thin-wall spherical shell type micro component. The method comprises the following specific steps:

Step 3.1: CCD tool setting: the workpiece-cutter contact area in the X-Z plane is monitored by a vertical CCD camera, the workpiece-cutter contact area in the X-Y plane is monitored by a horizontal CCD camera, and accurate tool setting under the constraint of micro-space scale can be realized by image processing and multi-axis linkage, and the specific operation steps are as follows:

Step 3.2: and (3) turning around, clamping and monitoring: during turning and secondary clamping, the contact area between the thin-wall spherical shell type micro component and the vacuum adsorption clamp needs to be monitored in real time through a vertical CCD, and the method specifically comprises the following steps:

Step 3.4: characteristic microstructure capture: after turning and clamping, the last micro-pit structure and the coordinates thereof during primary clamping and processing are required to be captured and identified and recorded as reference coordinates to be used as the reference of the coordinates of the primary micro-pits of the secondary turning and clamping. The specific operation flow is as follows:

step (6): according to the horizontal conversion relation of the step (1), converting the pixel coordinates obtained in the step (5) to obtain the actual position of the last micro-pit structure during the primary clamping processing, and completing capturing and identifying the characteristic micro-pit structure.

Step 3.3: monitoring the processing process: the image acquisition-processing process monitoring microscopic imaging system carries out omnibearing real-time monitoring on the state of a processing area, the appearance of a workpiece, the abrasion of a cutter and the like by a high-resolution CCD camera, and cooperatively realizes the high-precision processing of the surface micro-pit structure of the thin-wall spherical shell type micro-component, and the specific operation steps are as follows:

step (2): the microscopic amplification function of the high-resolution CCD camera is utilized, and the contact area of the workpiece and the cutter in the X-Y plane is monitored by the horizontal CCD camera, so that the morphology of the workpiece, the abrasion of the cutter and the like can be monitored in real time;

4. the machine tool stops running:

the machine tool stops running, comprises normal stop after finishing the processing of a specific structure of a workpiece and emergency stop when abnormality or safety risk occurs in the processing process, and is specifically analyzed as follows:

normal stop: after finishing the processing of the thin-wall surface characteristic junction, pressing a stop button on the control operation panel, and then realizing the program power down of the whole weak current control system through plc driving;

unconventional stopping: in the course of working, when the course of working appears unusual or appears the security risk, press emergency stop button, can cut off each axle power, effectively guarantee processingquality and operating personnel safety. After the scram button is pressed, each executive component realizes power-down protection, the total power supply of the weak current control system is not cut off, and after the fault is removed, the scram button is released, and the linkage control operation of each shaft can be continued.

Fifth step: system composition description:

the invention-weak current control system and device integrates five-axis linkage control, a high-speed milling axis independent control module and a double high-resolution CCD microscopic imaging system into a whole, is a special weak current control system for a five-axis linkage machine tool for micro milling of thin-wall spherical shell micro-components, and can realize weak current control of a five-axis linkage machine tool for high-precision machining of a micro-pit structure with the diameter of 1-5 mm, the shell thickness of 20-120 mu m, and the longitudinal dimension of tens to hundreds of more than 0.5-20 mu m, and the transverse dimension of 50-200 mu m;

the weak current control system has certain universality, and can realize the conventional control of a common five-axis machine tool after the double-high-resolution CCD microscopic imaging system is dismantled; the high-speed air bearing is independently controlled, the milling shaft is detachable, and a turning tool and accessories thereof are replaced, so that the weak current system control of the conventional lathe machining can be realized;

the weak current control system and the weak current control device special for the ultra-precise five-axis linkage machine tool based on micro milling of the thin-wall spherical shell micro-components are formed by cooperation of numerical control system software and hardware. The high-speed loading of the program and friendly man-machine interaction with the user are realized by combining the research and development industrial personal computer with the industrial display. The controller adopts a Delta Tau Power Umac type motion controller, the working main frequency (1 GHz) is high, the hardware 64-bit (double-precision) floating point calculation is high, the calculation speed is high, and a larger memory is supported. Each shaft driver adopts a TRUST company TA330 series driver, and the AB class push-pull amplification linear output has no zero dead zone, no crossover distortion and no electromagnetic noise. The X/Y/Z axis is driven by a Parker series high-precision linear motor in the United states, closed-loop compensation is carried out by a Heidenhain high-precision open type linear grating ruler in Germany, and high-precision linear reciprocating motion can be realized. The rotary table customized and produced by German AMETEK PRECITECH company is supported by the hydraulic bearing, so that the radial error is small, the positioning precision is high, and higher bearing capacity can be realized; the high-precision workpiece shaft of the model ISO5.5PG of the United states PI company is supported by air floatation, and has high axial and radial rigidity. The tool shaft adopts an ASD-080H25 high-speed air bearing tool main shaft of Levicron company, is provided with an independent controller and a driver, is integrated in a special control cabinet, can be independently controlled to realize high-speed and high-precision rotary motion, can be dismantled, and further expands other purposes of a weak current control system and a machine tool; . The microscopic imaging system adopts a water star second-generation PRO-2620 ten-thousand-pixel high-resolution CCD camera produced by large constant images, and can transmit image data through a USB3.0 data interface under various severe environments; the panel point-operated switch selects a Schneider strip lamp flat head self-reset normally open point-operated button, the knob switch selects a Schneider self-locking one-opening one-closing knob, and the scram button selects a Schneider rotary reset normally closed button.

While certain specific embodiments of the invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A special ultra-precise six-axis linkage machine tool for micro milling of thin-wall spherical shell micro components is characterized in that the six-axis linkage machine tool comprises: the six-axis linkage machine tool weak electric control system special for micro milling of thin-wall spherical shell micro components comprises a lathe bed (1), an X-axis motion unit (2), a Y-axis motion unit (3), a C-axis rotation unit (4), a primary clamping system (5), a vertical CCD camera (6), a ball end mill (8), a milling tool shaft (9), a turning clamping system (10), a B-axis turntable (11), a Z-axis motion unit (12) and a horizontal CCD camera (13); the X-axis movement unit (2) and the Z-axis movement unit (12) are horizontally arranged on the lathe bed (1) in a mutually vertical mode; the Y-axis movement unit (3) is arranged on the X-axis movement unit (2); the C-axis rotary unit (4) controlled by the circular grating feedback is arranged in the middle of the carriage of the Y-axis motion unit (3) and can move up and down; the primary clamping system (5) is arranged on the C-axis rotary unit (4), and the tail end of the primary clamping system (5) is used for adsorbing a hemispherical surface of a thin-wall spherical shell type micro component (7) to be processed; the horizontal CCD camera (13) is arranged on a transition plate on a B-axis turntable (11) on the Z-axis motion unit (12) through a first high-precision two-dimensional micro-displacement platform, and the lens axis of the CCD camera points to the center of a ball end mill; the vertical CCD camera (6) is arranged on a transition plate of the Y-axis motion unit (3) through a second high-precision two-dimensional micro-displacement platform; the turning clamping system (10) is arranged on the B-axis turntable (11) and can be arranged opposite to the primary clamping system (5) for adsorbing the other half sphere of the thin-wall spherical shell type micro component (7), a ball end milling cutter (8) for processing a plurality of micro pits on the surface of the thin-wall spherical shell type micro component (7) is arranged at the end of a rotor of the milling tool shaft (9), and a stator of the milling tool shaft (9) is detachably arranged on the B-axis turntable (11) through a shaft bracket; the angle between the corresponding axis of the rotor of the milling tool shaft (9) and the XZ horizontal plane is 10-15 degrees; the Z-axis moving unit (12) moves along the direction of the organ cover so as to drive the B-axis turntable (11) on the Z-axis moving unit to move together, and the Y-axis moving unit (3) and the primary clamping system (5) above the X-axis moving unit (2) move along the direction of the organ cover;

The six-axis linkage machine tool weak electric control system is used for controlling the X-axis movement unit (2), the Y-axis movement unit (3) and the movement parts on the Z-axis movement unit (12) on the superfinishing six-axis linkage machine tool special for micro milling of thin-wall spherical shell micro-components to do linear reciprocating movement, and the B-axis turntable (11), the C-axis rotation unit (4) and the rotation parts on the milling tool shaft (9) do rotary movement;

the six-axis linkage machine tool weak electricity control system comprises:

the B-axis subsystem comprises a B-axis driver, a B-axis rotary motor and a B-axis feedback grating; the B-axis driver is used for driving the B-axis rotary motor, the B-axis feedback grating is used for feeding back the motion position of the B-axis rotary motor, and the B-axis rotary motor is used for controlling the rotary part of the B-axis rotary table (11) to perform rotary motion;

the C-axis subsystem comprises a B-axis driver, a C-axis rotary motor and a C-axis feedback grating; the C-axis driver is used for driving the C-axis rotary motor, the C-axis feedback grating is used for feeding back the movement position of the C-axis rotary motor, and the C-axis rotary motor is used for controlling the rotary part of the C-axis rotary unit (4) to perform rotary movement;

the independent tool shaft control cabinet is used for controlling the start, stop and rotation speed of the milling tool shaft (9), the independent tool shaft control cabinet sends an instruction to a controller in the independent tool shaft control cabinet through a panel of the independent tool shaft control cabinet, and the controller sends an instruction to a driver in the independent tool shaft control cabinet, so that the start, stop and rotation speed of the milling tool shaft (9) are controlled;

The six-axis linkage machine tool weak electric control system special for micro milling of the thin-wall spherical shell micro-components also comprises a microscopic imaging system connected with the upper computer, wherein the microscopic imaging system comprises a tool setting subsystem and an image acquisition subsystem;

in the six-axis linkage machine tool weak electric control system special for micro milling of thin-wall spherical shell micro-components, a tool setting subsystem is used for monitoring primary clamping tool setting and secondary clamping tool setting, and the specific process comprises the following steps:

step (7): the Z axis is controlled to move by a corresponding distance, so that the vacuum adsorption is monitored during turning and clamping;

In the six-axis linkage machine tool weak electric control system special for micro milling of the thin-wall spherical shell micro component, the image acquisition subsystem is used for acquiring a surface micro pit image in the micro milling process of the thin-wall spherical shell micro component in real time so as to acquire the surface morphology of the thin-wall spherical shell micro component, and the specific process comprises the following steps:

2. The micro milling method for the thin-wall spherical shell micro component is realized based on the ultra-precise six-axis linkage machine tool special for micro milling of the thin-wall spherical shell micro component, and is characterized by comprising a tool setting step, a first hemispherical crown processing step, a turning clamping step and a second hemispherical crown processing step, wherein:

the tool setting step comprises the following steps:

the first hemispherical crown processing step comprises the following steps:

controlling the rotating platform of the B shaft to rotate forward by alpha;

the turning clamping step comprises the following steps:

the second hemispherical crown processing step comprises the following steps: