CN114029859A - Electric spark dressing process method based on small ball head grinding wheel - Google Patents
Electric spark dressing process method based on small ball head grinding wheel Download PDFInfo
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- CN114029859A CN114029859A CN202111273581.2A CN202111273581A CN114029859A CN 114029859 A CN114029859 A CN 114029859A CN 202111273581 A CN202111273581 A CN 202111273581A CN 114029859 A CN114029859 A CN 114029859A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B53/00—Devices or means for dressing or conditioning abrasive surfaces
- B24B53/06—Devices or means for dressing or conditioning abrasive surfaces of profiled abrasive wheels
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B53/00—Devices or means for dressing or conditioning abrasive surfaces
- B24B53/12—Dressing tools; Holders therefor
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Abstract
An electric spark dressing process method based on a small ball head grinding wheel relates to the technical field of grinding wheel dressing and is used for solving the problem of grinding wheel abrasion in the grinding process of complex-structure parts with small-size curvature radius. The technical points of the invention comprise: connecting the grinding wheel to be trimmed with the positive electrode of a pulse power supply, and connecting the tool electrode with the negative electrode of the pulse power supply to form a spark discharge loop; the tool setting of the grinding wheel to be dressed and the tool electrode before finishing dressing processing is finished, and the final feeding positions of the grinding wheel to be dressed and the tool electrode are determined; carrying out rough finishing and fine finishing on the grinding wheel to be finished; finishing the grinding wheel dressing when the precision of the grinding wheel to be dressed reaches a preset value. The invention improves the dressing efficiency and dressing quality of the grinding wheel, improves the recycling rate of the grinding wheel, and reduces the grinding cost and grinding efficiency in the grinding process of the complex-structure part with small-size curvature radius. The method has universality and can be popularized and used for electric spark in-situ dressing of various small-size ball grinding wheels.
Description
Technical Field
The invention relates to the technical field of grinding wheel dressing, in particular to an electric spark dressing process method based on a small-ball-head grinding wheel.
Background
Parts with complex structures and small-size curvature radii, which are made of hard and brittle materials such as fused quartz, engineering ceramics and the like, play an increasingly important role in advanced technical fields such as aerospace, optics, microelectronics and the like, because of the hardness and brittleness of the materials, the parts become typical parts which are difficult to machine, and ultra-precise grinding and polishing are currently ideal machining modes of the materials. In the ultra-precision grinding process, in order to meet the processing requirements of high surface quality and surface shape precision, a small-diameter ball head metal-based diamond grinding wheel is widely adopted, and the hardness of diamond abrasive particles and the wear resistance of a metal matrix material are perfectly combined. However, due to the limitation of the structural size of the grinding wheel, the grinding linear velocity adopted by the grinding processing is small, the granularity of the grinding wheel is small, the grinding wheel is easy to wear in the grinding processing process, and the surface shape precision of the worn grinding wheel directly influences the surface shape precision of part processing, so that the worn small ball head grinding wheel needs to be repaired.
Disclosure of Invention
In view of the above problems, the invention provides an electric spark dressing process method based on a small ball head grinding wheel, which is used for solving the problem of grinding wheel abrasion in the grinding process of a complex-structure part with a small curvature radius.
An electric spark dressing process method based on a small ball head grinding wheel comprises the following steps:
step one, mounting a grinding wheel to be dressed on a grinding wheel spindle to enable the grinding wheel to rotate around the axis of the grinding wheel spindle; mounting a tool electrode on an electric spindle, so that the tool electrode can rotate around the axis of the electric spindle and feed along the axis direction; connecting the grinding wheel to be trimmed with the positive electrode of a pulse power supply, and connecting the tool electrode with the negative electrode of the pulse power supply to form a spark discharge loop;
rotating the grinding wheel spindle to enable the axis of the grinding wheel to be trimmed and the axis of the tool electrode to form a fixed included angle;
thirdly, tool setting of the grinding wheel to be dressed and the tool electrode before finishing dressing processing is completed, and final feeding positions of the grinding wheel to be dressed and the tool electrode are determined;
rotating the grinding wheel spindle, electrifying a pulse power supply, and roughly finishing the grinding wheel to be finished;
rotating the grinding wheel spindle, electrifying a pulse power supply, and finely finishing the grinding wheel to be finished;
step six, detecting whether the precision of the grinding wheel to be dressed reaches a preset value, and finishing the grinding wheel dressing if the precision of the grinding wheel to be dressed reaches the preset value; and if not, repeating the fifth step until the precision of the grinding wheel to be trimmed reaches a preset value.
Further, the third step specifically comprises:
adjusting the relative position of the grinding wheel to be dressed and the tool electrode to ensure that the height of the center of the end face of the grinding wheel to be dressed is the same as the height of the center axis of the tool electrode, and feeding the tool electrode to a position which is at a fixed distance from the gap between the tool electrode and the grinding wheel to be dressed; acquiring an image containing a grinding wheel to be trimmed and a tool electrode by using a CCD (charge coupled device) camera and carrying out image processing to obtain edge characteristic points of the grinding wheel to be trimmed and the tool electrode;
step three, extracting the highest point A (x) of the edge characteristic point of the end face of the tool electrode in the imaging graph1，y1) And the lowest point B (x)1，y2) Extracting the highest point C (x) of the edge characteristic point of the end face of the grinding wheel to be dressed2，y3) And the lowest point D (x)3，y4) The coordinate of the center point O of the end face of the tool electrode in the imaging graph is
The coordinate of the central point O' of the end face of the grinding wheel to be dressed in the imaging graph is
Adjusting the position of the grinding wheel to be modified to ensure that the vertical coordinate of the end surface central point O' of the grinding wheel to be modified is equal to the vertical coordinate of the end surface central point O of the tool electrode, namely: y is1+y2＝y3+y4Recording the coordinate value (x ', y ') of the center O ' of the end face of the grinding wheel to be dressed in the imaging graph and the coordinate value of the working platform of the grinding wheel to be dressedPosition value P0；
Step three, the grinding wheel to be trimmed is retreated along the axis direction by a first fixed distance, so that the tool electrode does not interfere with the grinding wheel to be trimmed in the subsequent moving process; adjusting the position of the tool electrode to ensure that the transverse coordinate value of the center point O of the end surface of the tool electrode is the same as the recorded x' value, namely: x is the number of1The position of the center point of the end face of the tool electrode is the center of the spherical surface which is trimmed by the grinding wheel to be trimmed; withdrawing the tool electrode from the position by a second fixed distance, wherein the second fixed distance is half of the intermediate diameter of the tool electrode, the position of the tool electrode is the final feeding position of the trimmed tool electrode, and the position value P of the working platform where the tool electrode is positioned is recorded1；
Step three, the tool electrode is retreated by a third fixed distance, so that the grinding wheel to be trimmed does not interfere with the tool electrode in the subsequent moving process, and the working platform where the grinding wheel to be trimmed is located is fed to the recorded position value P0Then continuously feeding the grinding wheel to be dressed for a fixed distance along the axial direction of the grinding wheel to be dressed to a position value P0' the fixed feeding distance is the radius of the grinding wheel to be dressed, the center of the end face of the grinding wheel to be dressed is the top point of the spherical surface dressed by the grinding wheel, and the position P of the grinding wheel to be dressed0' is the final feeding position of the dressed grinding wheel.
Further, the final feed position of the grinding wheel to be dressed in step three is at its position value P0' further feeding forward by 50 μm in the axial direction; the final feed position of the tool electrode is at its position value P1And then feeding forwards for a fourth fixed distance, wherein the fourth fixed distance is obtained by calculation according to the diameter of the grinding wheel in the dressing process.
Further, the grinding wheel to be dressed is a metal-based diamond grinding wheel with the diameter of 3.8mm, the diameter of diamond abrasive particles of 5 microns and the grinding wheel concentration of 130%.
Further, the tool electrode is composed of a thin-wall cylinder and an insulating rod, the medium diameter of the thin-wall cylinder is 2.687mm, and the wall thickness of the thin-wall cylinder is 0.2 mm.
Further, in the second step, the included angle of the fixed space is 45 degrees.
Further, the trimming parameters set in the rough trimming process in the fourth step include: the peak current of the pulse power supply is 6.6A, the rotating speed of the grinding wheel spindle is 1000r/min, the feeding speed of the tool electrode is 10 mu m/min, the open-circuit voltage of the pulse power supply is 60V, the duty ratio is 25%, the frequency is 80kHz, and the rotating speed of the tool electrode spindle is 500 r/min.
Further, the trimming parameters set in the fine trimming process in the fifth step include: the peak current of the pulse power supply is 3.3A, the rotating speed of the grinding wheel spindle is 3000r/min, the feeding speed of the tool electrode is 8 mu m/min, the open-circuit voltage of the pulse power supply is 60V, the duty ratio is 25%, the frequency is 80kHz, and the rotating speed of the tool electrode spindle is 500 r/min.
Further, after the step six, the method also comprises a step seven: and putting the trimmed grinding wheel in an acetone solution for ultrasonic vibration cleaning.
Further, the preset value in the sixth step is that the precision error of the profile shape of the trimmed grinding wheel is within 3 μm, and the distribution and the protruding height of the abrasive particles are uniform.
The beneficial technical effects of the invention are as follows:
the method optimizes the dressing step of the small ball head grinding wheel, improves the dressing efficiency and the dressing quality of the grinding wheel, and effectively solves the problem of grinding wheel abrasion in the grinding process of the complex-structure part with small-size curvature radius; by adopting the grinding wheel electric spark dressing process parameters set in the method, the radius of the grinding wheel which can be processed reaches 1.9085mm, the radius error is 8.5 mu m, the face shape precision of the dressed grinding wheel is about 2.5 mu m, and the grinding wheel abrasive particles are fully exposed again after being dressed, are uniformly distributed, have good equal height and micro-blade performance and have better grinding capacity; the repeated utilization rate of the grinding wheel is improved, and the grinding cost and the grinding efficiency in the grinding process of the complex-structure part with the small-size curvature radius are reduced. The method has universality and can be popularized and used for electric spark in-situ dressing of various small-size ball grinding wheels.
Drawings
The present invention may be better understood by reference to the following description taken in conjunction with the accompanying drawings, which are incorporated in and form a part of this specification, and which are used to further illustrate preferred embodiments of the present invention and to explain the principles and advantages of the present invention.
FIG. 1 is an in-place electric spark dressing schematic diagram of a small-diameter ball grinding wheel in an embodiment of the invention;
FIG. 2 is a schematic diagram of the adjustment of the relative position of the spindles in the embodiment of the invention;
FIG. 3 is a schematic diagram of dressing and setting of a grinding wheel according to an embodiment of the present invention;
FIG. 4 is a tool setting schematic diagram and an actual imaging diagram in an embodiment of the invention;
FIG. 5 is a schematic diagram illustrating a dressing and tool setting process of a grinding wheel according to an embodiment of the present invention;
FIG. 6 is a schematic illustration of a wheel dressing in an embodiment of the invention;
FIG. 7 is a comparison of the grinding wheel dressing before and after the embodiment of the present invention.
Detailed Description
In order that those skilled in the art will better understand the disclosure, exemplary embodiments or examples of the disclosure are described below with reference to the accompanying drawings. It is obvious that the described embodiments or examples are only some, but not all embodiments or examples of the invention. All other embodiments or examples obtained by a person of ordinary skill in the art based on the embodiments or examples of the present invention without any creative effort shall fall within the protection scope of the present invention.
In the process of machining a small-size part with a curvature radius by using a small-ball-head grinding wheel, the adopted grinding wheel is a metal-based diamond grinding wheel, the grinding wheel is inevitably worn in the process of grinding hard and brittle materials such as fused quartz, engineering ceramics and the like, and electric spark discharge correction needs to be carried out on the small-ball-head grinding wheel so as to meet the surface shape precision requirement of machining the small-size part with the curvature radius. The method can ensure that the surface shape precision error of the diamond grinding wheel after electric spark trimming is controlled within 3 mu m, the distribution and the protruding height of the abrasive particles are uniform, and the requirement of the surface quality of the part with the complex structure and small curvature radius is met.
The principle of in-place electric spark dressing of the metal-based diamond ball head grinding wheel is shown in figure 1. The ball head grinding wheel is arranged on the grinding wheel spindle so as to rotate around the axis, and is connected with the positive electrode of the pulse power supply through a graphite electrode; the tool electrode consists of a pure copper thin-wall cylinder and a bakelite insulating rod, wherein the insulating rod is used for avoiding a conductive loop from being formed in a machine tool; the position of a grinding wheel working platform is fixed in the grinding wheel dressing process, the grinding wheel rotates around the axis of a spindle, a tool electrode is fed in the axis direction at a certain speed while rotating around the axis, and when the feeding speed of the electrode and the speed of discharging and corroding materials of the grinding wheel are balanced, a certain discharging gap is generated, so that a continuous and obvious discharging phenomenon occurs, discharging machining is realized, metal matrix materials are removed, abrasive particles are protruded, and the ball grinding wheel dressing process is completed.
The electric spark dressing of the small ball head grinding wheel refers to: the small ball head grinding wheel is processed by electric spark discharge erosion by using a tool electrode, the surface shape precision error of the grinding wheel profile is controlled within 3 mu m, and the abrasive particles are distributed and the protruding height is uniform. The electric spark dressing comprises the following specific steps:
the method comprises the following steps: and starting the machine tool, connecting a machine tool motion system, and returning each motion guide rail and the rotary table to zero.
Step two: mounting a grinding wheel blank to be dressed on a grinding wheel spindle so that the grinding wheel blank can rotate around an axis; the grinding wheel blank is a metal-based diamond grinding wheel with the diameter of 3.8mm, the diameter of diamond abrasive particles of 5 mu m and the grinding wheel concentration of 130%.
Step three: the tool electrode is arranged on the precise electric spindle and consists of a pure copper thin-wall cylinder and an electric wood insulating rod, the insulating rod is used for avoiding a conductive loop from being formed in a machine tool, the intermediate diameter of the thin-wall cylinder is 2.687mm, and the wall thickness is 0.2 mm.
Step four: the grinding wheel blank is connected with the positive pole of a pulse power supply through a graphite electric brush, and the tool electrode is connected with the negative pole of the pulse power supply to form a spark discharge loop.
Step five: in order to ensure that the relative spatial position of the central axis of the grinding wheel and the central axis of the tool electrode is correct, avoid the true sphericity error of the surface of the grinding wheel caused by the out-of-plane error of two axes, and realize the electric spark dressing of the ball head grinding wheel, the relative position of the grinding wheel spindle and the electrode spindle is adjusted before the grinding wheel dressing, so that the grinding wheel spindle rotates for a certain angle around the Z axis of a machine tool coordinate system, and the aim is to rotate the angle of the grinding wheel spindle, so that an included angle of 40 degrees is formed in the space of the grinding wheel axis and the tool electrode axis, and under the fixed included angle, the face shape precision of the grinding wheel dressing can reach a higher level, namely, the grinding wheel dressing precision is improved, as shown in fig. 2.
Step six: and (4) setting the tool of the grinding wheel to be dressed and the tool electrode before finishing dressing, and determining the final feeding positions of the grinding wheel to be dressed and the tool electrode.
According to the embodiment of the invention, during the diamond grinding wheel electric spark dressing process, the position of the grinding wheel is kept unchanged, the tool electrode is axially fed, and the final position error of the tool electrode feeding will cause the spherical radius error after the grinding wheel dressing, and the grinding wheel dressing is incomplete or over-dressing possibly. The position error of the grinding wheel has no influence on the surface shape precision of the surface of the grinding wheel after dressing, but the dressing of the grinding wheel can be incomplete. Therefore, before dressing, the position of the grinding wheel needs to be adjusted and the feed final position of the tool electrode needs to be calibrated, namely, tool setting is carried out. When the tool is adjusted, the sight line of the CCD camera is parallel to the horizontal plane and is vertical to the axis of the grinding wheel, the position of the grinding wheel is adjusted and the final feeding position of the tool electrode is calibrated through the micro-displacement workbench according to the coordinates of the characteristic points of the grinding wheel and the electrode in the CCD image, and the position is shown in figure 3. The method comprises the following specific steps:
step six: the relative position of the grinding wheel and the tool electrode is adjusted through the micro-displacement workbench, the central height of the end face of the grinding wheel is close to the central axis height of the tool electrode, and the tool electrode is fed to a position which is spaced from the grinding wheel by a fixed distance (for example, 2-3 mm).
Step six and two: and adjusting the position of the CCD camera to enable the grinding wheel and the tool electrode to be simultaneously positioned in the imaging range of the CCD camera, and then adjusting the focal length of the camera to enable the grinding wheel and the tool electrode to be clearly displayed on the control computer.
Step six and three: extracting the highest point A and the lowest point B of the electrode end face edge characteristic points in the imaging graph, and recording the coordinates (x) of the two points in the imaging graph1，y1) And (x)1，y2) Extracting the highest point C and the lowest point D of the edge characteristic points of the end surface of the grinding wheel, and recording the coordinates (x) of the two points in an imaging graph2，y3) And (x)3，y4) As shown in fig. 4. The coordinate of the central point O of the end face of the electrode in the imaging graph is
The coordinate of the central point O' of the end face of the grinding wheel in an imaging graph is
Step six and four: the position of the grinding wheel is adjusted by the micro-displacement workbench, so that the ordinate of the central point O' of the end surface of the grinding wheel is equal to the ordinate of the central point O of the end surface of the electrode, even if y1+y2＝y3+y4As shown in fig. 5 (a). Recording the coordinate value (x ', y ') of the center O ' of the end face of the grinding wheel in the imaging graph and the position value P of the micro-displacement workbench of the grinding wheel0。
Step six and five: the grinding wheel is retreated along the axis of the grinding wheel by a first fixed distance, and the first fixed distance is 10-15 mm, so that the tool electrode does not interfere with the grinding wheel in the subsequent moving process. The tool electrode position is adjusted by the micro-displacement workbench, so that the transverse coordinate value of the central point O of the electrode end face is the same as the recorded x' value, even if x is1At this time, the position of the center point of the end face of the electrode is the center of the sphere after being dressed by the grinding wheel, as shown in fig. 5 (b). And (3) retreating the tool electrode from the position by a second fixed distance, wherein the value of the second fixed distance is half (0.5d) of the intermediate diameter of the tool electrode, and the position of the tool electrode is the final position of electrode feeding during trimming, as shown in fig. 5 (c). Recording the position value P of the electrode micro-displacement workbench at the moment1And then exits the tool electrode.
Step six: retracting the tool electrode a third fixed distanceAnd the third fixed distance is 2-3 mm, for example, so that the grinding wheel does not interfere with the tool electrode in the subsequent moving process, and the grinding wheel micro-displacement workbench is fed to the recorded position value P0Then continuously axially fed for a certain distance to reach a working position P for dressing the grinding wheel0', the feed distance value is the grinding wheel radius R, as shown in FIG. 5 (d). The center of the end face of the grinding wheel is the top point of the spherical surface finished by the grinding wheel.
Sixthly, seventh step: the final grinding wheel and tool electrode feed position is shown in figure 6. From the tool setting process, the theory shows that P is0' and P1The final feeding positions of the grinding wheel and the tool electrode are respectively, but the final feeding positions can be obtained by subsequent dressing experimental experience, and the grinding wheel is required to be positioned at P for ensuring that the spherical surface of the grinding wheel is dressed more completely0' then feeding the material by 50 μm along the axis (ensuring small positive deviation); the final feed position of the tool electrode is required to be at P in consideration of the electrode wear error and the electrode axial position error during dressing1And continuing to feed for a certain distance on the basis, and analyzing by a subsequent dressing experiment, wherein when power supply parameters are fixed, the difference of the loss value of the electrode for each dressing machining is small and is about 20 mu m, on the basis, the micro-displacement platform of the electrode needs to stop the cutter repeatedly for many times when feeding to the position, the current diameter of the grinding wheel is extracted by a corresponding algorithm, when the diameter reaches the target size, the tool electrode is fed to the ideal position, and the specific feeding fourth fixed distance needs to be calibrated by combining the experiment and image detection.
Step seven: diluting the standard emulsified grinding fluid according to a ratio of 1:50, using the diluted standard emulsified grinding fluid as working fluid in a dressing process, and adjusting the position of a spray head of the dressing working fluid to enable the spray head to be aligned between a grinding wheel blank and an electrode.
Step eight: the electrical parameters of the pulse power supply are set to be open-circuit voltage 60V, duty ratio 25%, peak current 6.6A and frequency 80 kHz. The dressing efficiency of the grinding wheel under the electrical parameter is higher.
Step nine: the grinding wheel spindle is started, the rotating speed of the spindle is set to be 1000r/min, the electrode spindle is started, the rotating speed of the spindle is set to be 500r/min, and the electrode feeding speed is set to be 10 mu m/min.
Step ten: the working fluid pump is started, the pulse power supply is switched on, the electrode is fed at the speed of 10 mu m/min, and the process of preparing the ball grinding wheel by the cylindrical grinding wheel electric spark is started.
Step eleven: and finishing the rough finishing of the grinding wheel by the tool electrode according to the corresponding machining process parameters and the programmed machining track program.
Step twelve: and after the rough dressing of the grinding wheel is finished, closing the working liquid pump and the pulse power supply, and gradually reducing the rotating speed of the grinding wheel spindle and the tool electrode spindle until the grinding wheel spindle and the tool electrode spindle stop.
Step thirteen: the pulse power supply electrical parameters were set to an open circuit voltage of 60V, a duty cycle of 25%, a peak current of 3.3A, and a frequency of 80 kHz. The grinding wheel dressing is carried out under the electric parameters, so that higher precision of the surface shape of the ball head grinding wheel can be obtained.
Fourteen steps: the grinding wheel spindle is started and the set rotating speed is 3000r/min, the electrode spindle is started and the set rotating speed is 500r/min, and the electrode feeding speed is set to be 8 mu m/min.
Step fifteen: and starting a working fluid pump, switching on a pulse power supply, feeding the electrode at the speed of 8 mu m/min, and starting the process of further trimming the ball grinding wheel by electric sparks.
Sixthly, the steps are as follows: finishing the fine finishing of the grinding wheel by the tool electrode according to the corresponding machining process parameters and the programmed machining track program; detecting whether the precision of the grinding wheel to be dressed reaches a preset value, and finishing the grinding wheel dressing if the precision of the grinding wheel to be dressed reaches the preset value; if not, continuing to perform fine finishing until the precision of the grinding wheel reaches a preset value; the preset values can be set as: the precision error of the profile shape of the grinding wheel is within 3 mu m, and the distribution and the protruding height of the abrasive particles are uniform.
Seventeen steps: and according to the twelfth step, the working fluid pump, the pulse power supply, the grinding wheel spindle and the tool electrode spindle are sequentially closed, the machine tool is operated, the ball head grinding wheel is far away from the workpiece, a machine tool motion system is closed, and electric spark dressing of the grinding wheel is completed.
Eighteen steps: and putting the trimmed grinding wheel in an acetone solution for ultrasonic vibration cleaning.
The method for evaluating the surface quality and the surface shape accuracy of the dressed grinding wheel comprises the following specific steps:
the method comprises the following steps: the protruding condition of the abrasive particles on the surface of the grinding wheel is observed by adopting a microscope with ultra depth of field for amplifying 2000 times, and the surface quality of the grinding wheel after primary finishing is shown in figure 7. As can be seen from FIG. 7, the abrasive particles before dressing are worn to be flat, the space for containing the chips is reduced, the grinding capacity is greatly reduced, the abrasive particles after dressing are fully exposed again, the distribution is uniform, the equal-height micro-blade performance is good, and the grinding capacity is good.
Step two: measuring the surface shape precision of the finished grinding wheel by using a Taylor Hobson surface profiler, enabling a probe to pass through the vertex of a hemisphere of the grinding wheel, drawing 2mm circular arcs along different meridian directions, and taking the average value of roundness errors of a plurality of meridian circular arcs as the surface shape precision error of a ball head of the grinding wheel. In the profile measurement results of a group of experiments, the radius measurement value of the small ball head grinding wheel is 1.9085mm, the radius error is 8.5 mu m, and the surface shape error is 2.541 mu m, which all meet the requirement of the ball head grinding wheel on the surface shape precision of 3 mu m.
The electric spark dressing method for the small ball head grinding wheel is verified by processing experiments on a self-developed ultra-precise grinding machine tool, and can realize high-quality grinding of parts with complex structures and small-size curvature radii. The method optimizes the dressing step of the small ball head grinding wheel, improves the dressing efficiency and the dressing quality of the grinding wheel, and effectively solves the problem of grinding wheel abrasion in the grinding process of the complex-structure part with small-size curvature radius; by adopting the grinding wheel electric spark dressing process parameters set in the method, the radius of the grinding wheel which can be processed reaches 1.9085mm, the radius error is 8.5 mu m, the face shape precision of the dressed grinding wheel is about 2.5 mu m, and the grinding wheel abrasive particles are fully exposed again after being dressed, are uniformly distributed, have good equal height and micro-blade performance and have better grinding capacity; the repeated utilization rate of the grinding wheel can be improved, and the grinding cost and the grinding efficiency in the grinding process of the complex-structure part with the small-size curvature radius are reduced. The method has certain universality, and can be popularized and used for electric spark in-situ dressing of various small-size (phi 3-phi 10mm) ball head grinding wheels.
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this description, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as described herein. The present invention has been disclosed in an illustrative rather than a restrictive sense, and the scope of the present invention is defined by the appended claims.
Claims (10)
1. An electric spark dressing process method based on a small ball head grinding wheel is characterized by comprising the following steps:
step one, mounting a grinding wheel to be dressed on a grinding wheel spindle to enable the grinding wheel to rotate around the axis of the spindle; mounting a tool electrode on an electric spindle, so that the tool electrode can rotate around the axis of the electric spindle and feed along the axis direction; connecting the grinding wheel to be trimmed with the positive electrode of a pulse power supply, and connecting the tool electrode with the negative electrode of the pulse power supply to form a spark discharge loop;
rotating the grinding wheel spindle to enable the axis of the grinding wheel to be trimmed and the axis of the tool electrode to form a fixed included angle;
thirdly, tool setting of the grinding wheel to be dressed and the tool electrode before finishing dressing processing is completed, and final feeding positions of the grinding wheel to be dressed and the tool electrode are determined;
rotating the grinding wheel spindle, electrifying a pulse power supply, and roughly finishing the grinding wheel to be finished;
rotating the grinding wheel spindle, electrifying a pulse power supply, and finely finishing the grinding wheel to be finished;
step six, detecting whether the precision of the grinding wheel to be dressed reaches a preset value, and finishing the grinding wheel dressing if the precision of the grinding wheel to be dressed reaches the preset value; and if not, repeating the fifth step until the precision of the grinding wheel to be trimmed reaches a preset value.
2. The electric spark dressing process method based on the small ball head grinding wheel as claimed in claim 1, wherein the specific steps of the third step comprise:
adjusting the relative position of the grinding wheel to be dressed and the tool electrode to ensure that the height of the center of the end face of the grinding wheel to be dressed is the same as the height of the center axis of the tool electrode, and feeding the tool electrode to a position which is at a fixed distance from the gap between the tool electrode and the grinding wheel to be dressed; acquiring an image containing a grinding wheel to be trimmed and a tool electrode by using a CCD (charge coupled device) camera and carrying out image processing to obtain edge characteristic points of the grinding wheel to be trimmed and the tool electrode;
step three, extracting the highest point A (x) of the edge characteristic point of the end face of the tool electrode in the imaging graph1，y1) And the lowest point B (x)1，y2) Extracting the highest point C (x) of the edge characteristic point of the end face of the grinding wheel to be dressed2，y3) And the lowest point D (x)3，y4) The coordinate of the center point O of the end face of the tool electrode in the imaging graph is
The coordinate of the central point O' of the end face of the grinding wheel to be dressed in the imaging graph is
Adjusting the position of the grinding wheel to be modified to ensure that the vertical coordinate of the end surface central point O' of the grinding wheel to be modified is equal to the vertical coordinate of the end surface central point O of the tool electrode, namely: y is1+y2＝y3+y4Recording the coordinate value (x ', y ') of the center O ' of the end face of the grinding wheel to be dressed in the imaging graph and the position value P of the working platform where the grinding wheel to be dressed is located0；
Step three, the grinding wheel to be trimmed is retreated along the axis direction by a first fixed distance, so that the tool electrode does not interfere with the grinding wheel to be trimmed in the subsequent moving process; adjusting the position of the tool electrode to ensure that the transverse coordinate value of the center point O of the end surface of the tool electrode is the same as the recorded x' value, namely: x is the number of1The position of the center point of the end face of the tool electrode is the center of the spherical surface which is trimmed by the grinding wheel to be trimmed; withdrawing the tool electrode from the position by a second fixed distance, wherein the second fixed distance is half of the intermediate diameter of the tool electrode, the position of the tool electrode is the final feeding position of the trimmed tool electrode, and the position value P of the working platform where the tool electrode is positioned is recorded1；
Step three, the tool electrode is retreated by a third fixed distance, so that the grinding wheel to be dressed is not in contact with the tool electrode in the subsequent moving processThe tool electrode is interfered, and the working platform where the grinding wheel to be dressed is positioned is fed to the recorded position value P0Then continuously feeding the grinding wheel to be dressed for a fixed distance along the axial direction of the grinding wheel to be dressed to a position value P0' the fixed feeding distance is the radius of the grinding wheel to be dressed, the center of the end face of the grinding wheel to be dressed is the top point of the spherical surface dressed by the grinding wheel, and the position P of the grinding wheel to be dressed0' is the final feeding position of the dressed grinding wheel.
3. An electric spark dressing process method based on small ball head grinding wheel as claimed in claim 2, characterized in that the final feeding position of the grinding wheel to be dressed in step three is at its position value P0' further feeding forward by 50 μm in the axial direction; the final feed position of the tool electrode is at its position value P1And then feeding forwards for a fourth fixed distance, wherein the fourth fixed distance is obtained by calculation according to the diameter of the grinding wheel in the dressing process.
4. An electric spark dressing process method based on a small ball head grinding wheel as claimed in claim 3, characterized in that the grinding wheel to be dressed is a metal-based diamond grinding wheel with a diameter of 3.8mm, a diameter of diamond abrasive particles of 5 μm and a grinding wheel concentration of 130%.
5. The electric spark dressing process method based on the small ball head grinding wheel as claimed in claim 4, wherein the tool electrode is composed of a thin-wall cylinder and an insulating rod, the medium diameter of the thin-wall cylinder is 2.687mm, and the wall thickness is 0.2 mm.
6. The electric spark dressing process method based on the small ball head grinding wheel as claimed in claim 5, wherein the included angle of the fixed space in the second step is 45 °.
7. The electric spark dressing process method based on the small ball head grinding wheel as claimed in claim 6, wherein the dressing parameters set in the rough dressing process in the fourth step comprise: the peak current of the pulse power supply is 6.6A, the rotating speed of the grinding wheel spindle is 1000r/min, the feeding speed of the tool electrode is 10 mu m/min, the open-circuit voltage of the pulse power supply is 60V, the duty ratio is 25%, the frequency is 80kHz, and the rotating speed of the tool electrode spindle is 500 r/min.
8. The electric spark dressing process method based on the small ball head grinding wheel as claimed in claim 7, wherein the dressing parameters set in the fine dressing process in the fifth step include: the peak current of the pulse power supply is 3.3A, the rotating speed of the grinding wheel spindle is 3000r/min, the feeding speed of the tool electrode is 8 mu m/min, the open-circuit voltage of the pulse power supply is 60V, the duty ratio is 25%, the frequency is 80kHz, and the rotating speed of the tool electrode spindle is 500 r/min.
9. The electric spark dressing process method based on the small ball head grinding wheel as claimed in claim 8, characterized by further comprising a seventh step after the sixth step: and putting the trimmed grinding wheel in an acetone solution for ultrasonic vibration cleaning.
10. The electric spark dressing process method based on the small ball head grinding wheel as claimed in claim 9, wherein the preset values in the sixth step are as follows: the precision error of the profile shape of the trimmed grinding wheel is within 3 mu m, and the distribution and the protruding height of the abrasive particles are uniform.
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU6853881A (en) * | 1980-03-19 | 1981-09-24 | Boart International Limited | Dressing grinding wheels |
| EP0938949A1 (en) * | 1998-02-26 | 1999-09-01 | The Institute Of Physical & Chemical Research | Electrodeless electrolytic dressing grinding method and apparatus |
| CN101623847A (en) * | 2009-07-31 | 2010-01-13 | 哈尔滨工业大学 | Diamond ball head grinding wheel electric sparkle dressing cutter adjustment method based on two-time cutter adjustment process |
| CN101623848A (en) * | 2009-07-31 | 2010-01-13 | 哈尔滨工业大学 | Trimming method of metal-based diamond ball-end grinding wheel with minor diameter |
| CN103770006A (en) * | 2014-01-22 | 2014-05-07 | 西安工业大学 | Method for finishing diamond grinding wheel by utilizing electric spark, as well as disc-shaped electrode and device adopted |
| CN107263323A (en) * | 2017-08-16 | 2017-10-20 | 哈尔滨工业大学 | Ball-end grinding wheel dressing method in place during superfine grinding special-shaped thin wall structural member |
| CN110202478A (en) * | 2019-07-05 | 2019-09-06 | 湖南科技大学 | A kind of dressing method of arc-shaped skive |
| CN112792740A (en) * | 2021-02-09 | 2021-05-14 | 上海橄榄精密工具有限公司 | Method for trimming grinding wheel by electric spark |
-
2021
- 2021-10-29 CN CN202111273581.2A patent/CN114029859A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU6853881A (en) * | 1980-03-19 | 1981-09-24 | Boart International Limited | Dressing grinding wheels |
| EP0938949A1 (en) * | 1998-02-26 | 1999-09-01 | The Institute Of Physical & Chemical Research | Electrodeless electrolytic dressing grinding method and apparatus |
| CN101623847A (en) * | 2009-07-31 | 2010-01-13 | 哈尔滨工业大学 | Diamond ball head grinding wheel electric sparkle dressing cutter adjustment method based on two-time cutter adjustment process |
| CN101623848A (en) * | 2009-07-31 | 2010-01-13 | 哈尔滨工业大学 | Trimming method of metal-based diamond ball-end grinding wheel with minor diameter |
| CN103770006A (en) * | 2014-01-22 | 2014-05-07 | 西安工业大学 | Method for finishing diamond grinding wheel by utilizing electric spark, as well as disc-shaped electrode and device adopted |
| CN107263323A (en) * | 2017-08-16 | 2017-10-20 | 哈尔滨工业大学 | Ball-end grinding wheel dressing method in place during superfine grinding special-shaped thin wall structural member |
| CN110202478A (en) * | 2019-07-05 | 2019-09-06 | 湖南科技大学 | A kind of dressing method of arc-shaped skive |
| CN112792740A (en) * | 2021-02-09 | 2021-05-14 | 上海橄榄精密工具有限公司 | Method for trimming grinding wheel by electric spark |
Non-Patent Citations (1)
| Title |
|---|
| 张坤: "半球陀螺加工用球头砂轮修整装置研制与修整工艺研究", 《中国优秀博硕士学位论文全文数据库（硕士） 工程科技Ⅰ辑》 * |
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