阅读说明：本技术 一种微细超声复合电解加工系统 (Fine ultrasonic composite electrolytic machining system ) 是由 朱永伟 陈湾湾 李晶 于 2020-07-30 设计创作，主要内容包括：一种微细超声复合电解加工系统,涉及特种加工和微细加工包括：工具头、运动系统、超声发生系统、控制单元、脉冲电源以及电解液循环系统,另外还包括数字示波器和工业相机等加工状态监测装置。所述运动系统包括X轴进给机构、Y轴进给机构、Z轴进给机构,所述X轴进给机构上布置Y轴进给机构,所述电解液循环系统布置于Y轴进给机构上,所述电解液循环系统由X轴进给机构、Y轴进给机构进行X向、Y向调节；所述工具头安装于Z轴进给机构,由Z轴进给机构对工具头进行Z向调节。本发明定位精度高,进给平稳低速,伺服响应快,实时检测间隙状态,脉冲电源和超声振动与主轴伺服同步控制,工件及夹具与运动台体绝缘,操作空间大,关键部件耐腐蚀,具有实用性。(A micro-ultrasonic composite electrolytic machining system relates to special machining and micro-machining and comprises: the ultrasonic processing device comprises a tool head, a motion system, an ultrasonic generation system, a control unit, a pulse power supply, an electrolyte circulating system, a digital oscilloscope, an industrial camera and other processing state monitoring devices. The movement system comprises an X-axis feeding mechanism, a Y-axis feeding mechanism and a Z-axis feeding mechanism, the Y-axis feeding mechanism is arranged on the X-axis feeding mechanism, the electrolyte circulating system is arranged on the Y-axis feeding mechanism, and the X-axis feeding mechanism and the Y-axis feeding mechanism are used for adjusting the electrolyte circulating system in the X direction and the Y direction; the tool head is arranged on the Z-axis feeding mechanism, and the Z-axis feeding mechanism is used for adjusting the tool head in the Z direction. The invention has the advantages of high positioning precision, stable and low feeding speed, quick servo response, real-time gap state detection, synchronous control of the pulse power supply, ultrasonic vibration and main shaft servo, insulation of the workpiece and the clamp and the motion table body, large operation space, corrosion resistance of key parts and practicability.)

1. A micro-ultrasonic composite electrolytic machining system is characterized by comprising a tool head, a motion system, an ultrasonic generation system, a control unit, a pulse power supply, an electrolyte circulation system and a machining state monitoring device; the movement system comprises an X-axis feeding mechanism, a Y-axis feeding mechanism and a Z-axis feeding mechanism, the Y-axis feeding mechanism is arranged on the X-axis feeding mechanism, the electrolyte circulating system is arranged on the Y-axis feeding mechanism, and the X-axis feeding mechanism and the Y-axis feeding mechanism are used for adjusting the electrolyte circulating system in the X direction and the Y direction; the tool head is arranged on the Z-axis feeding mechanism, and the Z-axis feeding mechanism is used for adjusting the tool head in the Z direction; the Z-axis feeding mechanism is of a coarse-movement and fine-movement composite structure, and the fine-movement structure is positioned above the coarse-movement structure and can perform coarse adjustment and fine adjustment; the machining state monitoring device monitors the machining process in real time and adjusts machining parameters in time through the control unit.

2. The combined electrochemical machining system of claim 1, wherein the coarse motion structure of the Z-axis feeding mechanism is an open loop system formed by a stepping motor and a ball screw, and provides coarse positioning within a large range of motion; the precise structure of the Z-axis feeding mechanism is a closed-loop system formed by a servo motor driving a high-precision ball screw and a built-in high-resolution grating ruler.

3. The ultrasonic micromachining system of claim 1, wherein the machining state monitoring device includes a digital oscilloscope and an industrial camera.

4. The combined electrochemical micro-machining system as claimed in claim 1, wherein the ultrasonic generating system is a partially coupled non-contact power transmission system and has a structure in which the primary and secondary sides are not completely symmetrical.

5. The combined electrochemical micro-machining system as claimed in claim 4, wherein the ultrasonic generating system has an electrical compensation system, and a primary side compensation method and a secondary side uncompensation method are adopted.

6. The micro-ultrasonic composite electrochemical machining system according to claim 1, wherein the control unit comprises an electrical control system and control software, wherein the electrical control system adopts a programmable multi-axis motion control card as a core of the control system and is connected with an industrial personal computer through a bus.

7. The combined electrolytic machining system of claim 1, wherein the pulse power supply is a dual MOSFET tube for generating high frequency narrow pulse power supply with a minimum pulse width of 100ns, and pulse parameters can be continuously adjusted on-line.

8. The combined electrochemical micro-machining system according to claim 3, wherein the digital oscilloscope is used for displaying voltage signals in the workpiece, the electrolyte circulating system and the tool electrode loop in real time, and the image detection device adopts a CCD industrial camera.

Technical Field

The invention relates to special processing and micro-processing, in particular to a micro-ultrasonic composite electrolytic processing system.

Background

In modern industry, miniaturization and fine equipment play more and more important roles, and have more and more urgent special requirements on fine manufacturing. At present, precision parts with a fine structure are widely used in the fields of automobiles, biomedicine, precision instruments, aerospace and the like. With this trend, the processing demand of fine structures is increasing. In comparison, the micro-electrochemical machining process removes the workpiece material in the form of ions, and can realize micron, submicron and submicron precision in principle. The method has the advantages of no limitation of mechanical properties of materials, good integrity of the processed surface, online controllable size and the like. However, since the electrolytic machining uses an electrochemical reaction to dissolve the metal material, there are many problems in the machining efficiency for the special material, the machining localization, the dimension, the shape accuracy, the machining gap detection and control, and the like.

Disclosure of Invention

In order to solve the problems in the prior art, the invention designs a micro-ultrasonic composite electrolytic machining system, which meets the problems and requirements in the background technology.

A micro-ultrasonic composite electrochemical machining system comprising: the ultrasonic machining device comprises a tool head, a motion system, an ultrasonic generation system, a control unit (an electrical control system and control software), a pulse power supply, an electrolyte circulating system and a machining state monitoring device such as a digital oscilloscope, an industrial camera and the like. The movement system comprises an X-axis feeding mechanism, a Y-axis feeding mechanism and a Z-axis feeding mechanism, the Y-axis feeding mechanism is arranged on the X-axis feeding mechanism, the electrolyte circulating system is arranged on the Y-axis feeding mechanism, and the X-axis feeding mechanism and the Y-axis feeding mechanism are used for adjusting the electrolyte circulating system in the X direction and the Y direction; the tool head is arranged on the Z-axis feeding mechanism, and the Z-axis feeding mechanism is used for adjusting the tool head in the Z direction.

Furthermore, the motion system can realize two-dimensional X-Y plane motion, and a Z axis adopts a 'coarse motion + fine motion' composite structure;

furthermore, in the motion system, a Z-axis coarse motion part in a Z-axis feeding mechanism adopts a stepping motor and a ball screw to form an open-loop system, provides coarse positioning in a large motion range and is mainly used for tool electrode clamping preparation; the fine motion part is fixedly connected on the coarse motion part, a servo motor is adopted to drive a high-precision ball screw, and a high-resolution grating ruler is arranged in the fine motion part to form a closed-loop system.

Furthermore, the ultrasonic generation system adopts a partial coupling type non-contact electric energy transmission system and adopts a structure of which the primary side and the secondary side are not completely symmetrical.

Furthermore, the ultrasonic generating system is provided with an electrical compensation system and adopts a primary side compensation method and a secondary side uncompensation method.

The electric control system adopts a programmable multi-axis motion control card as the core of the control system, and related information instructions are transmitted and connected with an industrial personal computer through a bus.

In the electrolytic machining system, the pulse power supply adopts a double-channel MOSFET to generate a high-frequency narrow pulse power supply, the minimum pulse width is 100ns, the maximum current is 5A, and pulse parameters can be continuously adjusted on line.

The micro-ultrasonic composite electrolytic machining system is provided with a digital oscilloscope for displaying voltage signals in a workpiece-electrolyte-tool electrode loop in real time, and a CCD industrial camera is used for image detection.

The invention has the following functions and characteristics: the positioning precision is high, the feeding is stable and low-speed, the servo response is fast, the gap state is detected in real time, the pulse power supply and the ultrasonic vibration are synchronously controlled with the main shaft servo, the workpiece and the clamp are insulated from the moving table body, the operation space is large, the key parts are corrosion-resistant, and the practicability is realized.

Drawings

FIG. 1 is a schematic diagram of the principal components of a processing system;

FIG. 2 is a schematic diagram of an electrical model of a non-contact power delivery system for a processing system;

FIG. 3 is a block diagram (mm) of a partially coupled power transfer system of the processing system;

FIG. 4 is a graph of voltage and current waveforms after partial coupling compensation of the processing system;

FIG. 5 is an overall mechanical structure of the ultrasonic integrated tool shank of the machining system;

fig. 6 is a block diagram of the electric control unit of the processing system.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

As shown in fig. 1, a micro-ultrasonic composite electrochemical machining system includes: the ultrasonic generator comprises a mechanical and motion system, an ultrasonic generating system, a control unit (an electrical control system and control software), a pulse power supply, an electrolyte circulating system, a digital oscilloscope, an industrial camera and other processing state monitoring devices.

In the motion unit, the X-Y axis plane motion (X-axis feeding mechanism and Y-axis feeding mechanism) is realized by an electric control integral displacement platform and a crossed roller guide rail is adopted. The minimum motion resolution can reach 1um, and the closed-loop control of cooperation control unit to motion actuating mechanism, its positioning accuracy is 2um, and the repeated positioning accuracy is about 1.5 um.

In the Z-axis direction, a 'coarse motion + fine motion' composite structure is adopted, and the positioning precision is further improved. Z_cuThe coarse motion part of the shaft adopts a stepping motor and a ball screw to form an open-loop system, provides coarse positioning in a large motion range, is mainly used for tool electrode clamping preparation and processing workpieces with large scale change, and the shaft is locked in micro-machining; z_xiThe shaft fine motion part is fixedly connected on the coarse motion part and is driven by a servo motor, and a high-resolution grating ruler is arranged in the shaft fine motion part to form a closed-loop system. Z_xiThe shaft motion is driven by servo motor and is executed by high accuracy ball, and its motion resolution is 1.5um, and photoelectric encoder feedback motion signal realizes closed loop motion control, and positioning accuracy is 1.5 um. The high-speed rotating main shaft and the special fixture are clamped in the Z position_xiOn the shaft, aiming at different processing objects, the two main shaft mechanisms can be switched and used on the motion mechanism in place.

The designed processing system is combined with an ultrasonic processing unit, an ultrasonic vibration system in the ultrasonic processing unit is a main part, and main parts comprise an ultrasonic generator, a non-contact electric energy transmission system, an ultrasonic transducer, an ultrasonic amplitude transformer, an ultrasonic cutter and the like. When the system is in operation, the ultrasonic generator outputs ultrasonic frequency electric signals to provide electric energy for the operation of the ultrasonic transducer, the non-contact electric energy transmission system transmits the electric signals to the piezoelectric ultrasonic transducer in a non-contact electric energy transmission mode, so that the piezoelectric transducer can stably work in the rotating cutter handle, the piezoelectric ultrasonic transducer converts the electric energy into mechanical energy and outputs ultrasonic frequency mechanical vibration, the mechanical vibration is transmitted and further amplified through the ultrasonic amplitude transformer, and finally, the large-amplitude ultrasonic frequency mechanical vibration is output at the end part of the cutter, so that the cutter can carry out rotary ultrasonic machining on a workpiece.

The designed ultrasonic generating system adopts a partial coupling type non-contact power transmission system, and in order to achieve the aim that the ultrasonic knife handle can automatically change the knife, the partial coupling type power transmission system is designed to be a partially symmetrical structure, namely, the primary side coil is a partial annular structure, the secondary side coil is a complete annular structure, and the sections of the primary side coil and the secondary side coil are symmetrical. Wherein the electrical model of the non-contact power transmission system is shown in fig. 2, and the structural size of the designed partially-coupled power transmission system is shown in fig. 3. The wire in the designed coil is a copper enameled wire with certain temperature resistance, the coil framework is used as a supporting structure of the copper wire, the material needs to meet the conditions of no electromagnetic shielding effect, no conduction, good enough rigidity and heat resistance and the like, and epoxy resin is selected as the material of the coil framework according to the requirements. The magnetic core material is soft magnetic manganese-zinc ferrite, and the ferrite with the model number of DMR90 is selected. Considering the non-resonance state in the working process of the non-contact electric energy transmission system, the equivalent electrical network of the ultrasonic vibration system is electrically compensated by the design of the invention, so that the output amplitude of the ultrasonic transducer is improved to meet the requirement of rotary ultrasonic processing, the compensated ultrasonic vibration system outputs larger amplitude under smaller voltage excitation, and the compensated current and voltage waveforms are shown in figure 4. The power voltage and the primary side current are in the same phase, the system is in an electrical resonance state, and the voltage at the two ends of the ultrasonic vibrator and the current flowing through the ultrasonic vibrator are in the same phase approximately, so that the requirement of a processing system is met.

The designed non-contact ultrasonic system mainly comprises a static part and a rotating part: the static part mainly comprises an ultrasonic generator, a primary side compensation circuit, a primary side coil, a magnetic core and a bracket. The ultrasonic generator and the primary side compensation circuit are arranged outside the machine tool body, the primary side coil, the magnetic core and the bracket are fixed on the lengthened shaft, and the primary side coil is connected with the ultrasonic generator through the primary side compensation circuit. The rotating part is the ultrasonic integrated knife handle and mainly comprises three parts:

1) secondary coil, magnetic core and support. The secondary side is electromagnetically coupled with the primary side, and the secondary side coil is connected with the transducer through a lead.

2) Ultrasonic transducer, amplitude transformer and cutter. This part is the source of mechanical vibration and the transmission line.

3) A tool shank housing having a standard form of attachment. The knife handle structure can be connected with a machine tool spindle, and the shell mainly plays a role in connecting, supporting and protecting electric and machine parts. According to the research on an ultrasonic vibration system and a non-contact electric energy transmission system, the end face structure and the size of a machine tool lengthened shaft connected with a cutter handle are considered, a BBT30 type cutter handle is selected as a reference, a non-standard connection mode is designed, a nodal surface with the first processing theory amplitude of the amplitude transformer being 0 is selected, a threaded press block is adopted to fix the amplitude transformer, and a stepped amplitude transformer is adopted in the design. The final design overall mechanical structure is shown in fig. 5.

In the designed electrochemical machining system of the micro-ultrasonic composite electrochemical machining system, NaNO3 is used as electrolyte, and the mass fraction is 5%. The electrolytic power supply adopts a double-channel MOSFET to generate a high-frequency narrow pulse power supply, the minimum pulse width is 100ns, the maximum current is 5A, and pulse parameters can be continuously adjusted on line; the output pulse parameters of the motion control card can be controlled on line through a serial interface of the motion control card.

In the processing process, the electric control system adopts a programmable multi-axis motion control card as the core of the control system, and related information instructions are transmitted and connected with an industrial personal computer through a bus. An industrial personal computer in the electric control system is mainly used as an upper operating machine and is mainly responsible for graphical man-machine interaction, the industrial personal computer adopts a Windows operating system with stable performance, and communicates with a motion control card at regular time to transmit data, so that tasks with low real-time requirements such as processing parameter setting, state and coordinate display, dynamic simulation of a processing process and the like are realized.

The motion control card is used as a lower computer and is simultaneously responsible for tasks with high real-time requirements such as multi-axis motor speed and position control, track interpolation, machining gap state detection and control, pulse power supply synchronous control, ultrasonic vibration and the like. After the control and motion program is downloaded from the industrial personal computer to the memory of the motion control card, the high-speed digital signal processor (DSP or FPGA) in the motion control card and the industrial personal computer run in parallel, one-time cyclic scanning is completed in a very short time, and the judgment is rapidly made and the corresponding instruction is output, so that the real-time performance of the control is ensured. The process of the electrical control of the processing system is shown in fig. 6.

The motion control card integrates a certain number of A/D conversion interfaces and DI/DO digital input/output interfaces for controlling and communicating other devices. The control program measures interelectrode voltage and machining current in the machining process in real time through an A/D interface, detects the state of the pulse power supply through the interface, judges whether the machining state in the gap is normal or not according to the voltage and the current, performs main shaft servo control, and controls the pulse power supply to output on-off and be synchronous with the main shaft motion through an IO interface. The industrial personal computer drives the relay through an IO interface of the motion control card to control the electrolyte system.

In the processing process, in order to display the voltage signal in the workpiece-electrolyte-tool electrode loop in real time, a digital oscilloscope is used, the bandwidth of the digital oscilloscope is selected to be 2GHz in the designed processing system, and the time gating FFT function can be used for mixed domain analysis. The image detection device adopts a CCD industrial camera with the highest resolution of 2456 multiplied by 2058, adopts digital I/O interface control, and has the matched industrial magnifying lens with the magnification of 0.7 to 4.5 times. The image detection device can not only display the electrolytic machining state in real time, but also has the functions of online measurement, determination of the initial position of the machining tool head and the like.