WO2021003898A1

WO2021003898A1 - Pulsed discharge edge trimming apparatus and method for edge grinding grains of micro-grinding head

Info

Publication number: WO2021003898A1
Application number: PCT/CN2019/114163
Authority: WO
Inventors: 谢晋; 卢阔; 罗宜毫; 李文哲
Original assignee: 华南理工大学
Priority date: 2019-07-05
Filing date: 2019-10-29
Publication date: 2021-01-14
Also published as: CN110181403A

Abstract

A pulsed discharge edge trimming apparatus for edge grinding grains of a micro-grinding head, comprising a micro-grinding head edge trimming device and a monitoring device. The micro-grinding head edge trimming device comprises, from top to bottom, an upper electrode (4), a main shaft (1), a micro-grinding head (3), a lower electrode (2), a tool platform (5), a programmable power supply (10) and a device controller (11); and the monitoring device comprises a voltage sensor (6), a current sensor (7), a data acquisition module (8) and a decision-making control module (9). The pulsed discharge edge trimming apparatus for edge grinding grains of a micro-grinding head achieves an edge trimming process for diamond grinding grains on the tip end of the micro-grinding head, and achieves feedback control on the edge trimming process by means of the monitoring device, thereby reducing labor costs and effectively improving the stability of the edge trimming process. Also provided is a pulsed discharge edge trimming method for edge grinding grains of a micro-grinding head.

Description

Pulse discharge edge grinding device and method for edge abrasive particles of micro grinding head

Technical field

The invention relates to the technical fields of precision ultra-precision machining and intelligent manufacturing, and in particular to a pulse discharge edge sharpening device and method for edge abrasive particles of a micro-grinding head.

Background technique

At present, micro-manufacturing technology is developing in the direction of high degree of freedom, high precision, nano-mirror, large-area molding and mass production. Micro machining, mainly grinding, can ensure shape accuracy. However, the abrasive grains on the surface of conventional diamond tools are irregular, which is easy to leave fine cut marks on the surface of the workpiece, and when processing high-hard and brittle workpieces, edge burrs and structural embrittlement will occur due to the rapid wear of micro tools. The parts are difficult to reach the mirror surface. Micro groove processing mainly relies on laser processing or dressing wheel grinding, but laser processing cannot guarantee the bottom surface quality, and the tip radius of dressing wheel grinding is relatively large. In addition, for the grinding field, the decision-making of process parameters often depends on the field experience of the technicians. In addition, the grinding process usually takes a long time, and the fixed process flow cannot be combined with the actual process conditions, which easily causes unpredictable instability. However, manual real-time control consumes a lot of manpower and time cost.

In order to solve the above problems, "Pulse discharge dressing parameters and motion parameter control method for grinding wheel micro-abrasive smoothing" [Patent No.: 201710823408.2, Application Date: 2017.09.13] The patent discloses pulse discharge applied to diamond abrasive particles on the surface of the grinding wheel. Smoothing process, process parameters and control methods. However, the contact arc length of the grinding wheel and the electrode involved in the smoothing method described in this patent is 0.7-1.5mm, and the abrasive grain size is 24#～180#, and the contact arc length used by the vertical grinder is only 0.05-0.5mm. The cylindrical micro-grinding head, and the abrasive grain size does not involve the case of 180# or more (100μm or less).

Summary of the invention

technical problem

The solution to the problem

Technical solutions

The purpose of the present invention is to overcome the problems of micro-grinding, especially the grinding of hard and brittle materials, that the surface of the workpiece is difficult to achieve a mirror surface, and the micro-grooves are difficult to be precisely formed, and proposes a pulse discharge sharpening device and a micro-grinding head edge abrasive grain The method can effectively and controllably sharpen one or more surfaces of diamond abrasive grains on the edge of the micro-grinding head, and intelligently adjust the process parameters according to real-time monitoring indicators during the sharpening process to ensure the stability of the sharpening process Realization, thereby obtaining a micro-grinding head that is conducive to mirror grinding processing and micro-groove precision molding.

The purpose of the present invention is achieved by at least one of the following technical solutions:

A pulse discharge edge sharpening device for edge grinding particles of a micro-grinding head, comprising a micro-grinding head sharpening equipment and a monitoring device. The micro-grinding head sharpening equipment includes an upper electrode, a main shaft, a micro-grinding head, and a lower electrode from top to bottom , Tool platform, programmable power supply and equipment controller; said monitoring equipment includes voltage sensor, current sensor, data acquisition module and decision control module;

The front end of the spindle is equipped with a micro-grinding head; the upper electrode is connected to the micro-grinding head and clamped on the spindle; the lower electrode is fixedly connected to the tool platform; the positive and negative poles of the programmable power supply are respectively connected to the upper electrode and the lower electrode Are connected; the equipment controller is used to control the running direction, feed speed, distance, and rotation speed of the spindle and tool platform;

The voltage sensor and the current sensor are respectively connected to the data acquisition module for data transmission, and the data acquisition module transmits the collected voltage and current data to the decision control module in real time or in a fixed time;

The decision control module is used to analyze the collected data, adjust the process parameters, and respectively connect with the programmable power supply and the equipment controller for control.

Further, the tiltable angle of the main shaft is 0°-60°, and the rotation speed of the main shaft is 0-80000 rpm.

Further, the lower electrode is made of a conductive metal material; the flatness of the surface of the lower electrode is less than 1 μm, and the parallelism with the horizontal movement plane of the spindle and the tool platform is less than 1 μm.

Further, the diameter of the micro-grinding head is 0.05-5 mm, and the particle size of the diamond abrasive grains at the front end is 100#-600#.

Further, the programmable power supply can output a voltage range of 0-5000V.

A pulse discharge edge trimming method using the edge abrasive grains of the micro-grinding head as described above includes the steps:

1) Set the tilt angle of the spindle, and install a micro-grinding head on the front end of the spindle;

2) Control the main shaft to rotate at a speed of 0～80,000 rpm, and coordinate the movement of the tool platform to drive the micro-grinding head to the surface of the lower electrode;

3) Turn on the programmable power switch to load the upper electrode and the lower electrode with a voltage of 0-100V;

4) Set the cutting depth of the micro-grinding head on the surface of the lower electrode to 0-50 μm, and the coordinated movement of the spindle and tool platform makes the relative feed speed of the micro-grinding head relative to the lower electrode 0-100 mm/min at any time;

5) The micro-grinding head performs cutting and sharpening of the lower electrode. The cutting time of the micro-grinding head from cutting into the lower electrode to cutting out is 0 to 1500 minutes, completing the sharpening process of the micro-grinding head once.

Further, the cutting time is the total time for the micro-grinding head to cut in and cut out the lower electrode multiple times.

Further, the spindle speed, the programmable power supply voltage, the depth of cut, the relative feed speed, and the cutting time are all initial process parameters, which are determined by the decision control module using a neural network The input of the neural network is the diameter of the micro-grinding head 3, the grain size of the abrasive particles, and the desired cutting edge area.

Further, during the cutting process, it also includes the step: the data acquisition module transmits the process parameters obtained from the voltage sensor and the current sensor to the decision control module at an interval of 0 to 100 minutes, and the decision control module determines whether the process parameters are Normal, if there is an offset, adjust the process parameters, and transmit the process parameters to the programmable power supply and equipment controller to achieve real-time control.

Further, steps 1) to 5) are repeated under different spindle inclination angles to perform double-sided discharge trimming, so that the edge abrasive grains of the micro-grinding head obtain sharp angles of corresponding angles.

The beneficial effects of the invention

Beneficial effect

Compared with the prior art, the present invention has the following advantages:

1. The present invention effectively trims the diamond grit at the tip of the micro-grinding head through the pulse discharge assist, replacing the diamond grinding head that has not been sharpened in the traditional grinding process, and is beneficial to improve the service life of the grinding head. It is conducive to mirror processing, and the two-sided sharpening is conducive to the precision molding of micro grooves.

2. The present invention realizes the intelligent initial decision-making of the trimming process parameters by adding monitoring equipment to the traditional equipment. In addition, real-time timing monitoring of the state parameters in the processing process, intelligent adjustment of the process parameters, feedback control of the trimming process parameters, instead of manual long-time real-time control, greatly saving manpower and time costs.

Brief description of the drawings

Description of the drawings

Figure 1 is an overall schematic diagram of a micro-grinding head intelligent sharpening device based on electric discharge assist.

Figure 2a) shows the normal discharge waveform in the edge trimming process collected by the data acquisition module.

Figure 2b) is the discharge waveform diagram of the offset in the edge trimming process collected by the data acquisition module.

Fig. 3 is a characteristic diagram of the morphology of diamond abrasive grains after the sharpening by the intelligent sharpening device and method.

Figure 4 is a contour diagram of the edge of the micro-grinding head after both sides are sharpened.

Shown in the picture: 1-spindle; 2-lower electrode; 3-micro grinding head; 4-upper electrode; 5-tool platform; 6-voltage sensor; 7-current sensor; 8-data acquisition module; 9-decision control Module; 10-programmable power supply; 11-device controller.

Invention embodiment

Embodiments of the invention

The present invention will be further described below with reference to the drawings and embodiments, but the scope of protection of the present invention is not limited to this.

Example one

As shown in Fig. 1, a pulse discharge sharpening device for edge abrasive particles of a micro-grinding head includes a micro-grinding head sharpening equipment and a monitoring device. The micro-grinding head sharpening equipment includes an upper electrode 4 and a spindle from top to bottom. 1. Micro grinding head 3, bottom electrode 2, tool platform 5, programmable power supply 10 and equipment controller 11; the monitoring equipment includes voltage sensor 6, current sensor 7, data acquisition module 8 and decision control module 9;

The front end of the spindle 1 is equipped with a micro-grinding head 3; the upper electrode 4 is connected to the micro-grinding head 3 through a spring carbon rod, and is clamped on the spindle 1; the lower electrode 2 is fixedly connected to the tool platform 5; the programmable The positive and negative poles of the power supply 10 are respectively connected with the upper electrode 4 and the lower electrode 2; the device controller 11 is used to control the running direction, feed speed, distance and the rotation speed of the spindle 1 and the tool platform 5;

The voltage sensor 6 and the current sensor 7 are respectively used to connect to the data acquisition module 8 for data transmission, and the data acquisition module 8 transmits the collected voltage and current data to the decision control module 9 at a fixed time or in real time;

The decision control module 9 is used to analyze the collected data and adjust the process parameters, and is respectively connected to the programmable power supply 10 and the equipment controller 11 and can be controlled.

Specifically, the tiltable angle of the main shaft 1 is 0°-60°, and the rotational speed of the main shaft is 0-80000 rpm.

Specifically, the bottom electrode 2 is a conductive metal material, and its materials include iron, copper, and aluminum; the flatness of the surface of the bottom electrode 2 is less than 1 μm, and the parallelism to the horizontal movement plane of the spindle 1 and the tool platform 5 is less than 1μm.

Specifically, the diameter of the micro-grinding head 3 is 0.05-5 mm, and the particle size of the diamond abrasive grains at the front end is 100#-600#.

Specifically, the programmable power supply 10 can output a voltage range of 0-5000V.

Hereinafter, using the pulse discharge sharpening device of the edge abrasive grain of the micro-grinding head, the second embodiment verifies the feasibility of the corresponding sharpening method, and the third embodiment verifies the feasibility of the two-sided sharpening process to obtain a certain angle sharp angle.

Example two

In this embodiment, the inclination angle of the main shaft 1 is 45°; the material of the lower electrode 2 is cast iron; the diameter of the micro-grinding head 3 is 1mm, and the diamond abrasive grain size at the front end is 140#; the feed speed is 10mm /min.

A pulse discharge edge trimming method for edge abrasive grains of a micro-grinding head includes the steps:

S1, set the inclination angle of the spindle 1, install the micro grinding head 3 on the front end of the spindle 1;

S2. Control the spindle 1 to rotate at a speed of 20000 rpm, coordinate with the movement of the tool platform 5, and drive the micro-grinding head 3 to move to the surface of the lower electrode 2;

S3. Turn on the switch of the programmable power supply 10 to load the upper electrode 4 and the lower electrode 2 with a voltage of 10V;

S4. The cutting depth of the micro-grinding head 3 on the surface of the lower electrode 2 is 1 μm, and the coordinated movement of the spindle 1 and the tool platform 5 makes the relative feed speed of the micro-grinding head 3 relative to the lower electrode 2 at any time 10 mm/min;

S5. The micro-grinding head 3 performs cutting and sharpening on the lower electrode 2. The cutting time of the micro-grinding head 3 from cutting into the lower electrode 2 to cutting out is 120 minutes, completing the sharpening process of the micro-grinding head once.

Wherein, the rotation speed of the spindle 1 in step S2 is 20000 rpm, the programmable power supply 10 in step S3 is loaded with a voltage of 12.5V, the depth of cut in step S4 is 1 μm, the relative feed speed in step S4 is 10 mm/min, and the cutting time in step S5 is 120min is the initial process parameter, which is determined by the decision control module using neural network. The input of the neural network is the diameter of the micro-grinding head 3 is 1mm, the abrasive grain size is 140#, and the desired sharpening area is 500μm ^2. The specific construction, setting and training process of the neural network is the existing technology, and those skilled in the art can Make appropriate settings as needed, so I won’t repeat them here.

In the process of step S5, the data acquisition module 8 transmits the data obtained from the voltage sensor 6 and the current sensor 7 to the decision control module 9 at an interval of 1 min. The decision control module 9 judges whether the process parameters are normal or not, and makes a decision if there is an offset The process parameters are adjusted, and the process parameters are transmitted to the programmable power supply 10 and the equipment controller 11 to achieve real-time control. As shown in Figures 2a) and 2b), the discharge waveform diagrams of normal and offset in the sharpening process collected by the data collection module in this embodiment are respectively.

As shown in FIG. 3, it is a characteristic diagram of the morphology of diamond abrasive particles after sharpening by the intelligent sharpening device and method. The trimming areas of the three diamonds are 554.869μm ² , 494.278μm ² and 576.928μm ^{2 respectively} , and the average value is close to the expected tipping area of 500μm ² , which verifies that the device and method can achieve the reduction of diamond abrasive grains at the tip of the micro-grinding head Sharpening, and the feasibility of using intelligent decision-making and feedback control.

Example three

This embodiment applies the same sharpening method as the first embodiment to perform double-sided sharpening. In the first sharpening, the inclination angle of the spindle 1 is 15 degrees, and the inclination angle during the second sharpening is 45 degrees. The diameter of the micro-grinding head 3 is 2 mm, and the diamond abrasive grain size at the front end is 100#. As shown in Table 1, it is the various parameters of the two-sided sharpening process.

Table 1 Parameters of the two-time trimming process

[Table 1]

After the two-sided sharpening process is completed, the tool is grooved on the surface of the graphite plate to replicate the surface topography and profile, and the Taylor profiler CLI-1000 is used for inspection.

As shown in Figure 4, it is the contour map of the edge of the micro-grinding head after both sides are sharpened. After measurement, the angle of the abrasive grains on the edge of the micro-grinding head after sharpening is 149.5°, which is very close to the theoretical 150°; the tip radius is 3.1μm, which is much smaller than the tip radius of the traditional dressing wheel.

The above embodiments use the pulse discharge assisted edge sharpening process. The micro-grinding tip sharpening equipment can sharpen the edge diamond abrasive grains of the micro-grinding head with a diameter of 0.05-5mm, and the diamond abrasive grain size can be 100#～600# , It is mainly used to solve the problem of micro-cuts and cracks on the surface of the product in the ultra-precision grinding process due to the irregularities of the diamond abrasive grains of the micro-grinding head and the burrs and structural embrittlement produced during the processing, so as to achieve super-clean mirror grinding and micro grooves The groove is precisely formed. Use monitoring equipment to make preliminary decisions on the process parameters of the pulse discharge assisted edge sharpening process; and through the regular monitoring of the voltage, current and the motion parameters of the edge sharpening equipment during the edge sharpening process, the process status and the effect of the edge sharpening can be achieved To realize the feedback control function.

In summary, the device and method of pulse discharge edge sharpening for the edge abrasive grains of the micro-grinding head of the present invention can effectively sharpen the diamond abrasive grains at the tip of the micro-grinding head. The use of the micro-grinding head for grinding processing has It is beneficial to improve the processing quality of the workpiece surface; and through the intelligent decision-making and feedback control, it is possible to control the sharpening area to reach the set target value, without manual involvement in the whole process, which greatly saves manpower and time costs.

The above are the preferred embodiments and examples of the present invention, but the implementation of the present invention is not limited by the above content, and any other changes, modifications, substitutions, combinations, and modifications made without departing from the spirit and principle of the present invention Simplified, all should be equivalent replacement methods, and they are all included in the protection scope of the present invention.

Claims

A pulse discharge sharpening device for edge abrasive particles of a micro-grinding head, comprising a micro-grinding head sharpening equipment and monitoring equipment, characterized in that: the micro-grinding head sharpening equipment includes an upper electrode (4) and a main shaft from top to bottom (1), micro grinding head (3), bottom electrode (2), tool platform (5), programmable power supply (10) and equipment controller (11); the monitoring equipment includes voltage sensor (6), current sensor (7), data acquisition module (8) and decision control module (9);

A micro-grinding head (3) is installed at the front end of the main shaft (1); the upper electrode (4) is connected to the micro-grinding head (3) and clamped on the main shaft (1); the lower electrode (2) and the tool platform (5) Fixed connection; the positive and negative poles of the programmable power supply (10) are respectively connected to the upper electrode (4) and the lower electrode (2); the equipment controller (11) is used to control the spindle (1) and the tool The running direction, feed speed, distance of the platform (5) and the speed of the main shaft (1);

The voltage sensor (6) and the current sensor (7) are respectively connected to the data acquisition module (8) for data transmission, and the data acquisition module (8) transmits the collected voltage and current data to the decision-making control at a fixed time or in real time Module(9);

The decision control module (9) is used for analyzing the collected data, adjusting the process parameters, and is respectively connected with the programmable power supply (10) and the equipment controller (11) for control.
The pulse discharge sharpening device according to claim 1, characterized in that the tiltable angle of the spindle (1) is 0°-60°, and the spindle speed is 0-80,000 rpm.
The pulse discharge sharpening device according to claim 1, characterized in that: the lower electrode (2) is made of conductive metal material; the flatness of the surface of the lower electrode (2) is less than 1 μm, and is in line with the main shaft (1) and The horizontal movement plane of the tool platform (5) maintains a parallelism of less than 1 μm.
The pulse discharge sharpening device according to claim 1, characterized in that the diameter of the micro-grinding head (3) is 0.05-5 mm, and the size of the diamond abrasive grains at the front end is 100#-600#.
5. The pulse discharge sharpening device according to claim 1, wherein the programmable power supply (10) can output a voltage range of 0-5000V.
A method for sharpening the edge of the micro-grinding head by using the device according to any one of claims 1 to 5, characterized in that it comprises the steps of:

1) Set the inclination angle of the spindle (1), and install a micro-grinding head (3) at the front end of the spindle (1);

2) Control the main shaft (1) to rotate at a speed of 0～80,000 rpm, and cooperate with the movement of the tool platform (5) to drive the micro grinding head (3) to move to the surface of the bottom electrode (2);

3) Turn on the programmable power supply (10) switch to load the upper electrode (4) and the lower electrode (2) with a voltage of 0-100V;

4) Set the cutting depth of the micro-grinding head (3) on the surface of the lower electrode (2) to be 0-50μm, and the coordinated movement of the spindle (1) and the tool platform (5) makes the micro-grinding head (3) relative to The relative feed speed of the lower electrode (2) is 0～100mm/min;

5) The micro-grinding head (3) performs cutting and trimming on the lower electrode (2). The cutting time of the micro-grinding head (3) from cutting into the lower electrode (2) to cutting out is 0～1500min, completing a micro-grinding head repair Blade craft.
The method of pulse discharge sharpening edge abrasive grains of a micro-grinding head according to claim 6, characterized in that: the cutting time is the total time of the micro-grinding head (3) cutting in and cutting out the bottom electrode (2) multiple times .
The pulse discharge sharpening method for edge abrasive particles of a micro-grinding head according to claim 6, characterized in that: the rotation speed of the spindle (1), the loading voltage of the programmable power supply (10), the depth of cut, the The relative feed rate and the cutting time are both initial process parameters, which are obtained by the decision control module (9) using a neural network for decision-making, and the input of the neural network is the diameter of the micro-grinding head (3) and the abrasive grain size And the expected sharpening area.
The method of pulse discharge sharpening edge abrasive grains of a micro-grinding head according to claim 6, characterized in that, during the cutting process, it further comprises the step of: the data acquisition module (8) reads from the voltage sensor (6) at an interval of 0-100 min. ) And the process parameters obtained by the current sensor (7) are transmitted to the decision control module (9), and the decision control module (9) judges whether the process parameters are normal or not, if there is an offset, the process parameters are adjusted, and the process The parameters are transmitted to the programmable power supply (10) and the equipment controller (11) to achieve the purpose of real-time control.
According to any one of claims 6 to 9, the method of pulse discharge trimming of edge abrasive grains of a micro-grinding head, characterized in that steps 1) to 5) are repeated under different inclination angles of the spindle (1) to perform double-sided discharge trimming. The edge makes the abrasive grains at the edge of the micro-grinding head get a sharp angle corresponding to the angle.