CN207273009U - A kind of micro- tip abrasive particle electrothermal chemical retapering device of emery wheel - Google Patents

Abstract

The utility model discloses an electrothermochemical sharpening device for grinding wheel micro-tip abrasive grains, which comprises a power supply, a graphite electric brush, a micro-tip grinding wheel, a counter-grinding cone, a rotating device, a CNC grinding machine workbench, a current sensor, a voltage sensor, and an oscilloscope. The rotating device is fixed on the CNC grinding machine workbench, the counter-grinding cone is fixed on the rotating device, and the micro-tip grinding wheel, graphite brush, current sensor, power supply, and counter-grinding cone are connected sequentially by wires in a positive polarity manner. A discharge circuit is formed, and the voltage sensor and the current sensor are commonly connected to an oscilloscope. The utility model only needs to adjust the motion parameters of the CNC grinding machine to control the pulse discharge dressing parameters to obtain a good sharpening effect of the micro-tip and micro-abrasive particles of the grinding wheel; Wear, can realize precision grinding of non-hard and brittle materials.

Description

A grinding wheel micro-tip abrasive grain electrothermal chemical sharpening device

technical field

The utility model relates to a precision control technology for sharpening the tip of a micro-tip grinding wheel, in particular to an electrothermal chemical sharpening device for the micro-tip abrasive grain of the grinding wheel.

technical background

At present, the micro-grooves on the surface of parts are mainly formed by precision grinding of micro-tip grinding wheels formed by mechanical dressing. However, the mechanical dressing method only removes the bond of the micro-tip grinding wheels to make the abrasive grains out of the edge, which can control the micro-tips. Macroscopic morphology, but cannot control the micro-tip abrasive grain shape of the grinding wheel that affects the processing quality.

In order to solve this problem, "A method of sharpening and trimming large-grain diamond grinding wheel by air discharge", [Patent No.: ZL201310314120.4, date of authorization: 2016.01.06] discloses the in-air discharge of coarse diamond grinding wheel The method of sharpening and trimming, its principle is: during the dressing, the chips generated by the abrasive cutting copper-based electrode and the grinding wheel bond form a discharge gap to cause electric spark discharge, and the metal bond on the surface of the grinding wheel can be removed by pulse electric sparks, so that When the diamond abrasive grains come out of the edge, the instantaneous high temperature generated will also be transferred from the chips to the abrasive grains participating in the cutting, making the tip of the cutting edge graphitized, so as to achieve the effect of diamond abrasive grains for smoothing and trimming. The advantage of in-air discharge dressing technology is that only need to connect the discharge circuit between the grinding wheel and the electrode to perform dressing (abrasive sharpening and trimming), its sharpening efficiency is 5 to 10 times that of mechanical dressing, and it is environmentally friendly. In order to generate pulse discharge, in the prior art, the discharge gap is controlled within a range smaller than the edge height of the abrasive particles by reasonably setting the parameters of the open circuit voltage and the motion parameters of the CNC grinding machine. However, this technology has the following disadvantages:

1. The effect of abrasive grain trimming and trimming is not obvious. For example, using a copper electrode to trim a #46 diamond grinding wheel for 20 hours at an open circuit voltage of DC-25V, the grinding edge is significantly improved, but its shape basically does not change;

2. The molten copper scrap produced during the dressing process is easy to adhere to the surface of the grinding wheel, which affects the grinding of the abrasive grains.

3. The sharpening and trimming effect of abrasive grains is not easy to control, especially in the dressing process, the plowing action of the abrasive grain cutting edge will easily cause the surface of the copper electrode to form a bulge (reduce the discharge gap), and then generate a pulse arc discharge, resulting in grinding The grain surface structure is damaged or falls off directly.

The principle described in the patent "A Method for Dressing V-shaped Sharp Angles of Diamond Grinding Wheels by Electric Discharge in Air" (Application Publication No.: CN102490121A, Application Publication Date: 2012.06.13) is the same as "a large-grain diamond grinding wheel in air The "discharging sharpening and trimming method" patent is basically the same, and the difference in this technology is only that the grinding wheel is trimmed through the V-shaped grinding path to achieve the purpose of removing the grinding wheel bond and forming the V-tip. However, in addition to the problems in the above-mentioned patents, this technology still has the following deficiencies:

1. The grinding path of the grinding wheel from bottom to top makes the side of the micro-tip always contact the electrode before the top, which cannot effectively dress the micro-abrasive particles on the top of the grinding wheel;

2. The grinding path of the grinding wheel from bottom to top increases the cutting contact arc length of a single diamond abrasive grain, and it is impossible to control the pulse discharge dressing parameters by adjusting the motion parameters of the CNC grinding machine, and arc discharge is prone to occur during the dressing;

3. The electrode is fixed on the CNC grinding machine to keep the direction of the grinding force on the abrasive grains of the grinding wheel unchanged during dressing, and it is impossible to use the fragile surface of the diamond anisotropy to dress the abrasive grains.

In addition, "A micro-abrasive edge trimming device and online control method for coarse diamond grinding wheel", (Patent No.: ZL201511022295.3, date of authorization: 2017.06.02) discloses the use of a circular microstructure array The method of smoothing and leveling the diamond grinding wheel with the cast iron micro-powder diamond grinding disc is based on the principle that the iron element can reduce the graphitization temperature of the diamond abrasive grains, and use the cast iron micro-powder diamond grinding disc on the rotating disc The micro-abrasive grains on the edge of the flat diamond grinding wheel can be smoothed and trimmed. The diamond abrasive grains are thermally trimmed and removed by physical sliding, and the micro-structure array on the disc has the effect of chip heat dissipation, which can improve the dressing performance. However, the diamond micro-removal rate in this technology is low. Although the micro-abrasives can be thermochemically removed by physical sliding, the heat accumulation is slow and cannot meet the requirements of high-efficiency dressing. For example, using #60 diamond grinding wheel and rotating iron The electrode (without fine diamond particles) has to be ground for up to two weeks before the abrasive grains come out of the edge of the blade.

Utility model content

In order to overcome the shortcomings of the above-mentioned prior art, the utility model provides a grinding wheel micro-tip abrasive electrothermal chemical sharpening device and its online control method. The method only needs to control the pulse discharge dressing parameters by adjusting the movement parameters of the CNC grinding machine Obtain a good sharpening effect of the micro-tip and micro-abrasive grains of the grinding wheel. The working principle is: the use of rotating electrode dressing can use the characteristics of diamond anisotropy in the rotating grinding of the grinding wheel micro-abrasive grains, cone-shaped micro-abrasive grains and their base materials. Dress the fragile surface of the abrasive grains, and through the reasonable planning of the grinding path and the grinding force, grinding heat and instantaneous high temperature caused by the grinding of the grinding wheel micro-abrasive grains, cone-shaped micro-abrasive grains and their matrix materials The physical and thermochemical effects generated under the grinding wheel are sharpened with micro-tips and micro-abrasive grains.

The technical scheme that the utility model solves the problems of the technologies described above is:

An electrothermochemical sharpening device for grinding wheel micro-tip abrasive grains, including power supply, graphite brush, micro-tip grinding wheel, counter-grinding cone, rotating device, CNC grinding machine table, current sensor, voltage sensor, oscilloscope, the rotating device It is fixed on the CNC grinding machine workbench, the grinding cone is fixed on the rotating device, the center line of the rotating device is perpendicular to the center line of the micro-tip grinding wheel, and the micro-tip grinding wheel, graphite A brush, a current sensor, a power supply, and a grinding cone are connected to form a discharge circuit, and the voltage sensor is connected in parallel with the power supply and is jointly connected with an oscilloscope with the current sensor;

Further, the cone angle of the grinding cone is 60°≤β≤150°.

Further, the power supply is a DC/pulse power supply.

Compared with the prior art, the utility model has the following beneficial effects:

1. Using the rotating electrode method, through reasonable grinding path planning, the grinding wheel micro-abrasive grains, cone-shaped micro-abrasive grains and their matrix materials are ground against each other, and the parameters of the pulse discharge dressing are controlled by adjusting the movement parameters of the CNC grinding machine, which can improve the micro-tip. Sharpening efficiency of abrasive grains.

2. By tracking the dressing parameters of the pulse discharge, the number of effective abrasive grains on the micro-tip can be evaluated online, which avoids complicated and cumbersome detection and data processing processes, and creates favorable conditions for realizing the intelligent dressing process.

3. After dressing, the surface of the micro-tip grinding wheel has less molten matter, and the cutting edge of the tip micro-abrasive grains is high and the forming precision is high. It can be used for high-precision micro-groove grinding of non-hard and brittle materials.

Description of drawings

Figure 1 is a schematic diagram of the overall structure of the electrothermochemical sharpening device for the micro-tip abrasive grains of the grinding wheel.

FIG. 2 is an enlarged schematic diagram of point A in FIG. 1 .

Fig. 3 is a schematic diagram of the electrothermochemical sharpening of the micro-tip abrasive grains of the grinding wheel.

Figure 4a is a waveform diagram of EDM + arc discharge trimming.

Figure 4b is a waveform diagram of EDM trimming.

Figure 5a is an electron microscope image of chips produced by EDM + arc discharge trimming.

Figure 5b is an electron microscope image of chips produced by EDM trimming.

Fig. 6a is a schematic diagram of constant voltage and constant current control of DC power supply.

Figure 6b is the pulse discharge waveform diagram collected during trimming.

Fig. 7a is an electron microscope image of the micro-abrasive grains of the grinding wheel before dressing.

Fig. 7b is the SEM image of the micro-abrasive particles of the grinding wheel after dressing.

As shown in the figure: 1-power supply; 2-graphite brush; 3-micro-tip grinding wheel; 4-cone grinding platform; 9-Oscilloscope; 10-Grinding path; 11-Grinding wheel micro-tip diamond abrasive grains; 12-Grinding wheel side diamond abrasive grains; 13-Frustum diamond abrasive grains; 14-Pulse EDM; 15-Graphite; 16-Grinding place .

Detailed ways

The utility model will be further described in detail below in conjunction with the embodiments and accompanying drawings, but the implementation of the utility model is not limited thereto.

As shown in Figure 1, an electrothermochemical sharpening device for grinding wheel micro-tip abrasive grains, including a power supply 1, graphite brush 2, micro-tip grinding wheel 3, grinding cone 4, rotating device 5, CNC grinding machine table 6, Current sensor 7, voltage sensor 8, oscilloscope 9, described rotating device 5 is fixed on the CNC grinder workbench 6, and described grinding cone 4 is fixed on the rotating device 5, and the center line of described rotating device 5 is slightly The center line of the tip grinding wheel 3 is vertical, and the micro-tip grinding wheel 3, the graphite brush 2, the current sensor 7, the power supply 1, and the grinding cone 4 are connected to form a discharge circuit in a positive polarity manner, and the voltage sensor 8 and The power supply 1 is connected in parallel with the oscilloscope 9 together with the current sensor 7; the cone angle of the grinding cone 4 is 60°≤β≤150°. The power supply 1 is a direct current or pulse power supply.

An online control method of an electrothermal chemical sharpening device based on the micro-tip abrasive grains of the grinding wheel, comprising steps:

1) Set up the device, fix the grinding cone 4 on the rotating device 5 of the CNC grinding machine workbench 6, make the center line of the microtip grinding wheel 3 perpendicular to the center line of the rotating device 5, and use the wires to sequentially place the microtips in a positive polarity manner. Grinding wheel 3, graphite electric brush 2, current sensor 7, power supply 1, and grinding cone 4 are connected to form a discharge circuit, and the voltage sensor 8 is connected in parallel with the power supply 1 and is jointly connected with the oscilloscope 9 with the current sensor 7;

2) The parameter control of grinding wheel micro-abrasive sharpening, load the open circuit voltage E for the discharge circuit, collect the pulse discharge signal sent by the voltage sensor 8 and the current sensor 7 online through the oscilloscope 9 to obtain the pulse discharge voltage U and the pulse discharge current I, set Set the motion parameters of the CNC grinding machine, including the grinding wheel speed N _w , the grinding wheel feed speed v _f , the feed depth a _p and the rotation speed N _r of the rotating device, and control the pulse discharge voltage U and pulse discharge current I at 18~30V and 4~ Within the range of 10A, a stable pulse electric spark 14 appears on the surface of the grinding cone 4;

3) The sharpening operation of the grinding wheel micro-abrasive grains, the micro-tip grinding wheel 3 circulates along the grinding path 10 of the dressing angle β=α, and the matrix elements of the grinding cone 4 during the dressing promote the graphitization of the grinding wheel micro-abrasive grains, and pass through the grinding wheel micro-grinding. The physical and electrothermochemical effects of abrasive grains, conical micro abrasive grains and their matrix materials caused by the grinding force, grinding heat and instantaneous high temperature of electric spark discharge, and the sharpening of micro abrasive grains on the micro tip of the grinding wheel. ;

4) On-line detection of micro-abrasive particles at the tip of the grinding wheel, using the trimmed tip of the grinding wheel for discharge grinding, the pulse discharge current waveform generated by online detection and the cross-sectional profile of the workpiece scratches, calculate the effective number of abrasive particles n _d at the tip of the grinding wheel, and judge the grinding wheel The tip angle γ and the arc radius r of the micro-tip diamond abrasive grains 11; when the number of effective abrasive grains n _d is greater than the target value, and the detected scratch tip angle γ ₁ and the arc radius r ₁ respectively satisfy γ ₁ = γ = α When ±1° and r ₁ =r≤0.05mm, the CNC grinding machine stops working.

Specifically, in step 2), the feed speed v _f of the grinding wheel is determined by formula (1):

In the formula, W and α are the width and angle of the tip of the grinding wheel.

Specifically, in step 4), the number n _d of effective abrasive grains at the tip of the grinding wheel is determined by formula (2):

In the formula, t _m is the pulse discharge waveform acquisition time, n _e is the number of pulse discharge current peaks.

Specifically, in step 2), when the pulse discharge voltage U and the pulse discharge current I do not satisfy the 18-30V and 4-10A, by adjusting the motion parameters of the CNC grinding machine or/and the open circuit voltage of the power supply, until the pulse discharge voltage and The discharge current is re-stabilized within the range of 18-30V and 4-10A.

Specifically, adjust the CNC grinding machine motion parameters or/and power supply open circuit voltage as follows:

When the pulse discharge voltage U<18V and the pulse discharge current I<4A, reduce the grinding wheel feed speed v _f or/and feed depth a _p or/and open circuit voltage E;

When the pulse discharge voltage U>30V and the pulse discharge current I>10A, increase the grinding wheel feed speed v _f or/and feed depth a _p or/and reduce the open circuit voltage E.

Specifically, in step 1), the particle size of the microtip grinding wheel 3 is 20-400 mesh diamond abrasive grains, and the microtip angle is 60°≤α≤150°; the particle size of the grinding cone 4 is 100-400°. 2000 mesh diamond abrasive grains, the matrix material contains iron and chromium.

Specifically, in step 2), the grinding wheel speed of the CNC grinding machine motion parameters is 250rpm≤N _w ≤2500rpm, the grinding wheel feed speed is 10mm/min≤v _f ≤500mm/min, and the grinding wheel feed depth is 1μm≤a _p ≤ 3 μm, rotating speed of the rotating device is 10rpm ≤ N _r ≤ 500rpm; the open circuit voltage of the power supply 1 is 23V ≤ E ≤ 35V, and the pulse discharge voltage U is not lower than the set open circuit voltage E within the range of 2-5V.

Referring to Fig. 1～Fig. 7 below, take the tip abrasive sharpening of the diamond emery wheel (diameter 150mm, thickness 4mm) of 46 orders 120 ° tip as an example, describe the electrothermal chemical sharpening device of the grinding wheel micro-tip abrasive grain of the present utility model in detail And the working principle of its online control method, and then verify the technical effect of the utility model.

The overall structure of the electrothermochemical sharpening device for the micro-tip abrasive grains of the grinding wheel is shown in Figure 1. The open-circuit voltage E is applied to the discharge circuit of the electrothermochemical sharpening device for the micro-tip abrasive grains of the grinding wheel, and the motion parameters of the CNC grinding machine are adjusted, including the grinding wheel speed N _w , the feed speed v _f of the grinding wheel, the feed depth a _p , the rotational speed of the rotating device N _r , the micro-tip grinding wheel 3 circulates along the grinding path 10, so that a stable pulse electric spark 14 appears on the grinding cone 4 and reaches the micro-tip diamond of the grinding wheel The purpose of sharpening the abrasive grains 11, the pulse discharge signal sent by the current sensor 7 and the voltage sensor 8 collected online by the oscilloscope 9 can be adjusted through the movement parameters of the numerical control grinding machine to control the sharpening effect of the micro-tip diamond abrasive grains 11 of the grinding wheel (as shown in Figure 2 ).

The electrothermochemical sharpening principle of the micro-tip abrasive grains of the grinding wheel is shown in Figure 3. The micro-tip grinding wheel 3 circulates according to the grinding path 10, and the side of the grinding wheel and the counter-grinding cone 4 play a grinding role, so that the raised grinding debris and the grinding wheel A discharge gap is formed between the surfaces of the bonding agent, and a pulse electric spark discharge is generated under the open circuit voltage E of the power supply 1 . On the one hand, the instantaneous high temperature generated by the pulse electric spark 14 can melt and erode the metal bond on the surface of the grinding wheel, so that the diamond abrasive grains come out of the edge; Graphite 15 formed by the electrothermal chemical graphitization of diamond abrasive grains appears on the surface of the micro-abrasive grains, and the frustum diamond abrasive grains 13 on the frustum-cone substrate are easy to produce counter-grinding with the friable surface of the micro-abrasive grains of the grinding wheel at the grinding place 16, and then Promote the sharpening of the micro-tip diamond abrasive grains 11 of the grinding wheel and the smoothing of the diamond abrasive grains 12 on the side of the grinding wheel.

Whether controlling the pulse discharge dressing parameters and motion parameters during the dressing process can promote diamond graphitization, and then obtain a good grinding wheel micro-tip and micro-abrasive sharpening effect, can be verified by theory and experiments.

When the diamond is heated to 900°C, the binding force between the carbon atom crystals on the surface weakens, and graphitization begins. As the temperature rises, the graphitization accelerates. After 1050°C, the entire crystal rapidly graphitizes, and the chemical reaction is O ₂ +2C _diamond →2CO, 2CO+C _diamond →CO ₂ +2C _graphite . However, diamond begins to graphitize when heated to 750°C under the action of iron and chromium elements, and its surface is completely graphitized at 850°C, that is, the iron element reduces the graphitization temperature of diamond by about 150-200°C. Therefore, in the technology described in the utility model, adopt iron, chromium and other elements to make up the purpose of dressing the grinding cone to be to reduce the graphitization temperature of the micro-abrasive grains of the emery wheel.

Taking a single diamond micro-abrasive particle (diameter 350 μm) as an example to simulate and analyze the temperature field in the dressing process, the grinding wheel speed N _w and table feed speed v _f in the motion parameters are replaced by the contact between the abrasive grain and the workpiece surface Time, and set the workpiece material to 45 steel. The simulation results show that when grinding with the motion parameters of N _w = 2400rpm, v _f = 80mm/min and a _p = 1μm, the surface temperature of the micro-abrasive grains (that is, the temperature in the grinding zone) is 600°C, and the graphitization of diamond has not been achieved. Minimum temperature; if a heat source (instantaneous high temperature generated by pulse electric spark discharge) is added to the top of the raised abrasive debris, the surface temperature of the diamond abrasive grains has been as low as 800-900°C by simulating. Under the catalysis of other elements, graphite 15 appears on the diamond abrasive grains. During the grinding process, the cutting edge of graphite 15 appears on the diamond abrasive grains 12 on the side of the grinding wheel through grinding force. Therefore, the technology described in the utility model can theoretically realize rapid sharpening of micro-abrasive particles.

The premise of rapid graphitization of diamond is to absorb enough heat. In the above-mentioned "a device and method for trimming and leveling the edge of the micro-abrasive grains of a coarse diamond grinding wheel", only the rotating disk is used to dress the micro-abrasive grains of the grinding wheel, and the grinding heat generated by the physical sliding mode generated It is impossible to rapidly graphitize the diamond surface, so the smoothing efficiency of micro-abrasive particles is low; and in "a method of sharpening and trimming large-grain diamond grinding wheels by gas discharge", the heat generated by gas discharge can make the grinding wheel micro-abrasive particles Graphitization, but this technology uses copper-based electrodes, and copper elements cannot reduce the graphitization temperature of diamonds, so even if the surface of micro abrasive grains absorbs more heat, the temperature generated is not enough to cause graphitization of diamond abrasive grains . In addition, during the dressing process, the grinding force generated by grinding the copper electrode with the grinding wheel is smaller than that of the iron electrode, so it is difficult for the copper electrode to smooth the micro-abrasive particles without graphitization.

As shown in Figure 4, in the process of adjusting motion parameters, as the feed depth increases, the generated pulse discharge waveform and wear debris will have completely different changes. It should be noted that the utility model defines the discharge forms in Fig. 4a and 4b as electric spark+arc discharge and electric spark discharge respectively. When the open-circuit voltage of pulse discharge is 23V≤E≤35V, when the feed rate is 200rpm≤v _f ≤500rpm, the amplitude of pulse discharge voltage U is easily lower than 18V and unstable, and it is easy to drop below 5V, while the pulse discharge current I The frequency of _c is greater than 500Hz, and the amplitude is less than 4A; as shown in Figure 4b, when the feed rate is 10rpm ≤ v _f ≤ 200rpm, the amplitude of the pulse discharge trimming parameters is larger and more stable, and the frequency of the pulse discharge current I is generally Less than 100Hz. As shown in Figures 5a and 5b, compared with EDM + arc discharge, the grinding debris generated by EDM dressing is doped with a large amount of spherical melt. The necessary condition for diamond graphitization is to absorb enough heat. Figures 4 and 5 illustrate that the heat released by EDM is much greater than that of EDM + arc discharge, so the lower limit of the effective pulse discharge voltage U needs to be set.

As the trimming time goes by, the pulse discharge voltage U and pulse discharge current I under the spark discharge tend to increase, and the increase of the pulse discharge trimming parameters means the increase of the discharge gap (external load). On the one hand, the greater the external load, the more heat energy the discharge circuit consumes, that is, the less heat energy the abrasive particles can absorb, which directly affects the graphitization effect of the micro abrasive particles; on the other hand, the spattered particles during the dressing process Under the action of electric spark discharge, the grinding debris will be fully melted and attached to the surface of the grinding wheel, which directly affects the sharpening effect of the micro-abrasive particles. When the pulse discharge voltage U increases from 30V to 31V, the pulse discharge current I is greater than 10A, and the molten iron attached to the surface of the grinding wheel increases significantly. Therefore, considering the sharpening effect of tip micro-abrasive grains, it is necessary to set the upper limit value of U for the effective pulse discharge voltage.

To sum up, when the pulse discharge voltage U is less than 18V, it is easy to generate electric spark + arc discharge; It is necessary to control the pulse discharge voltage U within the range of 18-30V.

It should be emphasized that the technology described in the utility model is not a simple superposition of the prior art. The essential difference is that it is the sharpening of the micro-abrasive particles at the tip of the grinding wheel, rather than the sharpening of the tip shape of the grinding wheel. In the dressing process, only Reasonably planning the grinding path, and controlling the motion parameters of the CNC grinding machine and the pulse discharge dressing parameters can make the micro-tip abrasive grains of the grinding wheel obtain a good sharpening effect. Due to the difference in the theoretical basis and methods of process parameter control, even if those skilled in the art combine the basic common sense and limited experiments in this field, they cannot obtain the pulse discharge voltage of 18-30V and the micro-grinding of the grinding wheel tip as defined by the utility model. Grain sharpening effect.

The working principle and necessity of the electrothermochemical sharpening device and the online control method of the grinding wheel micro-tip abrasive grains of the present utility model are illustrated below through examples:

First, a 46-mesh 120° micro-tip diamond grinding wheel (diameter D=150mm, bronze bond) is installed on the grinding wheel shaft of a CNC precision grinding machine (SMART 818), and the iron-based grinding cone 4 is fixed on the center of the rotating device 5 Above, it is connected with graphite brush 2, oscilloscope 9 (DS1102E), DC power supply 1, voltage sensor 8 and current sensor 7 in a positive polarity manner to form a discharge circuit. The working principle of the DC power supply 1 is shown in Figures 6a and 6b. The constant voltage and constant current control unit in the power supply 1 can adaptively adjust the input voltage/current (U _i /I _i ) of the discharge circuit according to the load R. During the trimming process, the load increases with the increase of the discharge gap, so the pulse discharge voltage U detected by the sensor is the input voltage (DC) after the power supply is adaptively adjusted, and its occurrence time is not limited to the pulse duration of the pulse discharge current I time.

Then with open circuit voltage E=30V, grinding wheel speed N _w =2400rpm, grinding wheel microtip width W and angle α are 4mm and 120° respectively, set rotating device speed N _r =10～250rpm, feed depth a _p =1～ Experiments were carried out at 3 μm, and the feed speed of the grinding wheel v _f =23-577mm/min was calculated according to formula (2), and the rotation speed of the rotating device was specified to be increased by 10 rpm each time until the continuous pulse electric spark discharge rate η _c was less than 80%, and each time The accumulative feeding depth of trimming ∑a _p =3a _p , the next feeding depth is carried out, the purpose is to obtain the motion parameters of high-efficiency CNC grinding machine under high discharge efficiency. The experimental phenomenon shows that with the increase of the rotation speed of the rotating device, the continuous pulse electric spark discharge rate η _c is stable above 90% at first, and then rapidly drops to 60% due to the accumulation of wear debris, which is used as the evaluation standard.

By observing the pulse electric spark phenomenon and pulse voltage and current signals, and optimizing the motion parameters of the CNC grinding machine, the grinding wheel speed N _w = 2400rpm, the grinding wheel feed speed v _f = 184mm/min, the grinding wheel feed depth a _p = 3μm, and the rotation speed of the rotating device N _r = 80rpm, so that the 46-mesh 120° micro-tip grinding wheel moves with a grinding path with a dressing angle of β = 120°.

As shown in Figures 7a and 7b, the micro-tip and micro-abrasive grains of the grinding wheel are sharpened under electrothermochemical dressing, and the tip angle γ=120.8° is close to the dressing angle β, and the trimming plane of the micro-abrasive grains on the side of the grinding wheel is the same as that of the bond reference plane. parallel. The workpiece is subjected to electric discharge grinding with the motion parameters of the CNC grinding machine with the grinding wheel speed N _w =250rpm, the feed speed v _f =10mm/min, and the feed depth a _p =1μm. The number of pulse discharge current peaks collected within 5 minutes is about 5300 , then the effective microtip abrasive particles calculated by the formula (2) in step 4) is 5; then detect the cross-sectional profile of the workpiece scratches, the scratch tip angle γ ₁ =121.6° and tip arc radius r ₁ =0.041 mm, indicating that the micro-tip abrasive grains of the grinding wheel have been sharpened.

In summary, using the above steps to sharpen the micro-tip grinding wheel not only has less molten material on the surface of the grinding wheel, but also has a good molding effect of the tip micro-abrasive grains, and can online evaluate and control the number of effective micro-abrasive grains and their morphology characteristics. A precision sharpening technique for microtip grinding wheels.

The above-mentioned embodiments of the present utility model are only examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. All modifications, equivalent replacements and improvements made within the spirit and principles of the utility model shall be included in the protection scope of the claims of the utility model.

Claims (3)

1. a kind of micro- tip abrasive particle electrothermal chemical retapering device of emery wheel, is characterized in that：Including power supply, electrographite brush, micro- tip sand Take turns, to grinding core platform, rotating device, numerically control grinder workbench, current sensor, voltage sensor, oscillograph, the rotating dress Put and be fixed on numerically control grinder workbench, described to be fixed to grinding core platform on the spinning device, the center line of the rotating device The center line of micro- tip emery wheel is perpendicular, is successively passed micro- tip emery wheel, electrographite brush, electric current in a manner of positive polarity using conducting wire Sensor, power supply, connect and compose grinding core platform discharge loop, the voltage sensor and power sources in parallel and the rear and current sense Device connects oscillograph jointly.

2. the micro- tip abrasive particle electrothermal chemical retapering device of emery wheel according to claim 1, is characterized in that：It is described to grinding core platform Angle of taper for 60 °≤β≤150°。

3. the micro- tip abrasive particle electrothermal chemical retapering device of emery wheel according to claim 1, is characterized in that：The power supply is straight Stream/the pulse power.