CN111077347B - Atomic Force Microscopy Probe Holder - Google Patents

Abstract

The invention relates to an atomic force microscopy probe clamping device, which comprises a probe base, wherein the probe base is used for installing a probe substrate, the probe base is provided with a first inclined plane and a second inclined plane which respectively form a first included angle and a second included angle with a horizontal plane, the first included angle is smaller than the second included angle, and a probe substrate positioning groove for loading the probe substrate is arranged on the first inclined plane; clamping tool positioning grooves are formed in the two sides of the probe substrate positioning groove; after the probe substrate is arranged in the probe substrate positioning groove, the clamping tool positioning grooves are positioned on two sides of the middle part of the probe substrate.

Description

Atomic Force Microscopy Probe Holder

technical field

The invention relates to the technical field of scanning probe microscopy, in particular to a device for clamping and fixing atomic force probes in atomic force microscopy instruments.

Background technique

Atomic Force Microscopy (AFM) is a scanning probe microscopy imaging technique that enables people to observe the surface structure of a sample with nanometer or even atomic precision. AFM imaging can be performed directly in the atmosphere without the need to maintain extreme conditions such as ultra-high vacuum; it can also observe the surface of the sample in an environment close to the physiological conditions of the sample. The working principle of AFM is to use a microcantilever with a needle tip at one end to approach the sample surface and generate a force interaction with it. By detecting the interaction information between the needle tip and the sample, it is collected point by point in a raster scanning manner, and finally drawn with computer software. A high-resolution image of the surface structure of the sample is produced. At present, the principle based on optical lever detection is used in common AFM technologies, and the micro-cantilever probe is a mechanical sensor fabricated by modern micro-machining technology. Typical probe structures include: tip, cantilever and probe substrate. In addition to the conventional topography imaging and mechanical detection functions, the samples can be observed in various modes such as electricity and magnetism by covering the probe with thin-film materials with different functions.

Usually in the process of actually operating the AFM for experiments, the first step is to load the AFM probe onto the instrument. Then in the process of scanning and imaging, after the needle tip scans the surface of different test materials, the sharpness of the needle tip will inevitably decrease due to the existence of wear effect; or the needle tip adheres to the impurity particles on the surface of the sample during the scanning process ; these factors will lead to a decrease in the resolution of the observed image and even the appearance of artifacts. Damaged or no longer sharp probes need to be replaced from time to time to ensure measurement accuracy. Finally, after using the AFM instrument and equipment, in order to facilitate other users to continue to use, it is necessary to take out the loaded probe and put it back into the probe box.

Due to the small size of the probe, especially the microcantilever, the operability part is mainly the probe substrate. It is difficult to manually operate the probe when directly loading the probe onto the instrument or removing the probe from the instrument, and it is easy to be caused by humans. Damage to the probe.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is provided an atomic force microscopy probe holding device, comprising a probe base for mounting a probe substrate, the probe base having a first inclined surface and a The second inclined surface respectively forms a first included angle and a second included angle with the horizontal plane, the first included angle is smaller than the second included angle, wherein a probe base for loading probe substrates is arranged on the first inclined surface chip positioning groove; both sides of the probe substrate positioning groove are provided with clamping tool positioning grooves; after the probe substrate is loaded into the probe substrate positioning groove, the clamping tool positioning groove on both sides of the middle of the probe substrate.

According to an embodiment, the atomic force microscopy probe clamping device further includes a clamping base and a pressure-sliding assembly, the pressure-sliding assembly includes a spring, a fixing screw and a pressure-sliding sheet, the pressure-sliding sheet is provided on There is a body part, a sliding hole part and a forward extension part, the clamping base includes a spring accommodating hole, a threaded hole, and a probe base mounting part, one end of the spring is arranged in the spring accommodating hole, the body The sliding part is arranged at the other end of the spring for pressing the spring, and the fixing screw passes through the sliding hole part and is connected with the threaded hole, so as to connect the pressing sliding piece and the spring It is arranged on the clamping base, which can push the body part, and the sliding hole part is used to make the forward extension part move back and forth. The probe base is installed on the probe base installation part, so When the protruding part moves to the front part, the protruding part presses the probe substrate provided on the probe base, and when the protruding part moves to the front part, the probe substrate is released .

According to an embodiment, the forward extension portion and the body portion form a third included angle, the third included angle is smaller than the first included angle, and the second included angle is greater than 45 degrees.

According to one embodiment, the ratio of the second included angle to the difference between the first included angle and the third included angle is greater than 15 and less than 25, and the difference between the first included angle and the third included angle is Greater than or equal to 3 degrees and less than or equal to 5 degrees.

According to an embodiment, the second included angle is 60 degrees, the first included angle is 15 degrees, and the third included angle is 12 degrees.

According to an embodiment, a piezoelectric ceramic block is provided between the probe base and the probe base mounting part; the spring is a compression spring, the spring accommodating hole is a blind hole, and the end of the blind hole is provided with A via hole for easy installation; the clamping tool positioning groove is semicircular, and the probe substrate positioning groove is square.

According to an embodiment, the atomic force microscopy probe clamping device further includes a probe holder fixing base, the probe base is provided with at least two connecting holes, and the probe holder fixing base is provided with corresponding screw The probe holder fixing base and the probe base are fixedly connected by the connecting hole and the screw hole.

According to an embodiment, the probe holder fixing base has three positioning points, and each positioning point includes two positioning pin grooves and a circular hole, and the difference between adjacent groups of positioning pin grooves is 120 degrees. A positioning pin is arranged in the pin groove.

According to an embodiment, the two connecting holes are provided with a notch near the edge of the base body, so that the types of connecting components can be selected in a wider range.

The above angles do not exclude various processing errors during manufacturing.

According to an embodiment, the probe holder fixing base has two magnet slots, the magnet slots are cylindrical blind holes, magnets are arranged in the magnet slots, and the ends of the blind holes are provided with via holes for easy installation.

Embodiments of the present invention provide a probe holding and fixing device that allows an operator to place or take out an AFM probe more conveniently and reliably, and by using the device, the operator can more easily load the AFM probe onto the instrument body .

Description of drawings

In order to explain the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings that need to be used in the embodiments of the present invention. It should be noted that these drawings are schematic and do not limit the scope of protection of the present invention, nor are they drawn to scale.

FIG. 1 shows a perspective view of a probe holding device with a top surface facing upwards according to an embodiment of the present invention;

Fig. 2 shows a perspective view of a probe holding device according to an embodiment of the present invention with the bottom surface facing upward;

FIG. 3 shows an exploded view of the assembly of the probe holding device according to an embodiment of the present invention;

Figure 4 shows a perspective view, a bottom view and a front view of a clamping base according to an embodiment of the present invention;

Figure 5 shows a perspective view, a side view and a top view of a pressing slide according to an embodiment of the present invention;

FIG. 6 shows a schematic cross-sectional view of the probe holding device according to an embodiment of the present invention after installation;

7 shows a perspective view of a probe base according to an embodiment of the present invention and a schematic diagram of the area covered by a milling cutter trajectory during machining operations;

Figure 8 shows a perspective view, a front view and a top view after it is combined with a metal or ceramic sheet;

9 shows a schematic diagram of clamping a loading probe according to an embodiment of the present invention when a tweezer is used as a clamping tool, and a schematic diagram for comparing the differences in different positions of the probe substrate operated by the tweezers.

Detailed ways

In order to illustrate the purpose and specific embodiments of the present invention more clearly, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. These descriptions are all exemplary and do not limit the scope of protection of the present invention.

Fig. 1 shows a perspective view of the probe holding device according to an embodiment of the present invention with the top surface facing upward; Fig. 2 shows the bottom surface of the probe holding device according to an embodiment of the present invention facing upwards. The perspective view of the upper state; FIG. 3 shows an assembled exploded view of the probe holding device according to an embodiment of the present invention. As shown in FIGS. 1 to 3 , a probe holding device according to an embodiment of the present invention mainly includes a probe holding mechanism 10 and a probe holder fixing base 20 .

As shown in FIGS. 1 to 3 , the probe clamping mechanism 10 includes a clamping base 101 , and the clamping base 101 is provided with a connecting hole 1013 (see FIG. 4 ). The probe holder fixing base 20 includes a fixing base 201, and the fixing base 201 is provided with screw holes. According to one embodiment, the screw hole is threaded. The screw 109 and the screw 108 can pass through the connecting hole on the clamping base 101 and be threadedly connected with the screw hole provided on the fixing base 201, so as to connect the clamping base 101 and the fixing base 201, that is, the probe The frame fixing base 20 and the probe holding mechanism 10 are connected.

A threaded interface is provided on one side of the fixing base of this embodiment of the present invention, and probe clamping mechanisms of different structures can be fixed through threaded connection, which increases the flexibility of the entire device.

The fixed base 201 can be a cubic structure made of metal materials such as aluminum alloy or stainless steel as processing raw materials.

There are three positioning points 210 on the fixed base 201 . Each positioning point includes two positioning pin grooves and a positioning circular hole, and the difference between each adjacent group of positioning pin grooves is 120 degrees. The positioning pins 204 and 205, the positioning pins 206 and 207, and the positioning pins 208 and 209 are arranged in the positioning pin grooves of the corresponding positioning points. It should be noted that the three positioning points here are for matching with the equipment to which the probe holder fixing base 20 is to be installed, and there may be more or less positioning points. For example, the positioning structure of three steel balls can be preset on the main body of the instrument, which can be matched with the three positioning points 210 of this embodiment. The locating pin can be cylindrical, and the cylindrical locating pin (about 1.5mm in diameter) can be fixed in the grooves on both sides of the positioning circular hole by bonding, and the groove spacing is equivalent to the radius of the positioning steel ball on the main body of the instrument (about 4.5mm). The positioning point 210 and the positioning pins 204 to 209 may be collectively referred to as a positioning mechanism.

The fixed base 201 is also provided with two magnet slots 211 for installing the magnets 202 and 203 respectively. The magnets 202 and 203 can be made of NdFeB magnets, with a diameter of about 6mm and a thickness of about 3mm, and more magnets and magnet slots can be selected according to the cooperation with the instrument. The magnet slot may be a cylindrical blind hole, and the end of the blind hole is provided with a via hole for easy installation. After the positioning between the fixture base and the instrument interface is good, the two magnets on the fixture base and the corresponding two magnets on the instrument body will generate enough attractive force to ensure sufficient binding force between the fixture base and the instrument body. . The magnet and the magnet slot can be collectively referred to as a positioning guarantee mechanism. The use of a magnetic loading and positioning structure can simplify the mechanical structure of the positioning guarantee mechanism, and the fixed base can be removed without other tools, which is convenient for the operator to directly load or take out the clamping device with the probe and its base. At the same time, the wear of the mechanical device caused by repeatedly disassembling and assembling the clamping device and its base from the instrument and equipment is also reduced. The probe holder fixing base 20 mainly fixes the probe holding mechanism 10 on the instrument according to the positioning point 210 , the magnet and the magnet slot.

The probe holder fixing base 20 of this embodiment of the present invention adopts an assembling manner, which is convenient to process and flexible to assemble.

Figure 4 shows perspective, bottom and front views of a clamping base according to an embodiment of the present invention. As shown in FIG. 3 and FIG. 4 , the clamping base 101 according to an embodiment of the present invention includes a base body and two connecting parts arranged on both sides of the base body, and the connecting parts are provided with connecting holes 1013 , and a notch portion 1016 is provided on the two connecting holes near the edge of the base body. Between the two connecting parts, a component connecting part 1015 is provided, and two sides of the component connecting part 1015 are provided with grooves 1014, which can facilitate wiring, for example, leads from a piezoelectric ceramic block or from a needle tip. A screw hole 1011 and a spring accommodating hole 1012 are provided at the rear of the component connecting portion 1015, and a probe base mounting portion is provided at the front thereof. In the illustrated embodiment of the present invention, the threaded hole 1011 is a through hole, but it may also be a blind hole. The spring receiving hole 1012 is a blind hole. Blind holes are holes that do not penetrate through the whole. In one embodiment, a small via hole (the via hole is a through hole) is provided at the bottom of the blind hole, so as to facilitate the installation of the spring. For example, a guide is used to introduce the spring into the hole through the via, and the guide is removed. Such an embodiment also expands the choice of springs.

The spring 106, the fixing screw 111, and the pressure-sliding sheet 102 together constitute a pressure-sliding assembly.

FIG. 5 shows a perspective view, a side view, and a top view of the pressing slide 102 according to an embodiment of the present invention. As shown in FIG. 5 , the pressing slide 102 according to an embodiment of the present invention includes a main body portion 1023 , a sliding hole portion 1022 provided on the main body portion 1023 , and a forward pressing portion 1021 .

The main function of the pressure sliding sheet 102 is to cooperate with the pressure spring and the fixing screw to form a lever structure to fix the probe substrate 103 in the probe groove. In one embodiment, the pattern in the figure can be engraved on a metal sheet (eg, stainless steel or copper sheet) with a thickness of about 0.2 mm by means of laser processing. Several feature areas include a rectangle whose top is slightly smaller than the width of the AFM probe substrate (about 1.6mm), which can ensure that the probe substrate in the positioning groove of the probe base 105 is pressed; the diameter of the oblong hole in the middle is slightly larger than that of the fixed The screw diameter of the fixing screw of the sliding piece, such as a flat head screw (the screw diameter is about 2mm), and the length of the oblong hole (the length in which the fixing screw can slide) is about 3.5mm, which can ensure that the position of the rectangular part at the front end of the pressure sliding piece is completely Remove it from the probe groove; use mechanical sheet metal to make an inclination angle of about 12 degrees (the third inclination angle) on the front section of the metal sheet; make a structure that bends about 90 degrees on both sides of the rear end to prevent direct manipulation of the metal by hand Was cut during the film. Put the spring 106 (can be a compression spring, about 2.5mm in diameter, 5mm in length) into the round hole, adjust the tightening degree of the flat-head screw that fixes the sliding plate, so that the compression spring generates a certain pre-pressure, due to the lever effect, the pressure slip The other end of the sheet will generate downward pressure, which will be used to hold the probe substrate in the positioning groove of the probe base.

FIG. 6 shows a schematic cross-sectional view of the probe holding device according to an embodiment of the present invention after installation.

As shown in FIG. 3 to FIG. 6 , when installing the device, first make the bottom surface of the clamping base 101 face up, set the piezoelectric ceramic block 107 on the component connecting part 1015 of the clamping base 101 , and then place the The probe base 105 to which the blocking sheet (which can be metal or ceramic material) 104 is bonded is disposed on the piezoelectric ceramic block 107 . The blocking sheet 104 can be considered as an integral part of the probe base 105 . In one embodiment, the ceramic block can be fixed to the component connection part 1015 of the clamping base 101 by means of, for example, bonding; the piezoelectric ceramic block and the probe base 105 can also be fixed together by means of bonding or the like .

Then, set the spring 106 in the spring accommodating hole 1012 of the clamping base 101 , set the main body 1023 of the pressing slide 102 on the spring 106 , and make the fixing screw 111 pass through the sliding hole of the pressing slide 102 1022 , which is connected with the threaded hole 1011 , so that the pressing sliding piece 102 and the spring 106 are arranged on the clamping base 101 . Due to the existence of the sliding hole portion 1022, the pressing sliding piece 102 can move back and forth.

When loading the probes, first move the pressing slide back to prevent the forward pressing portion 1021 from covering the probe groove and affecting subsequent probe installation. Finally, the probe substrate 103 is set in the probe groove of the probe base 105 . Lift the forward pressing portion 1021 of the pressing slide and push the pressing slide 102 forward; lower the forward pressing portion 1021 to press and fix the probe 103, thereby completing the loading of the probe.

Figure 7 shows a perspective view of a probe base according to an embodiment of the present invention. FIG. 8 shows a perspective view, a front view, and a top view after it is combined with the blocking sheet 104 .

As shown in FIG. 7 and FIG. 8 , the probe base according to an embodiment of the present invention has two inclined surfaces (a flat inclined surface 1054 and an inclined surface 1055 ), which respectively form an included angle of 15 degrees and 60 degrees with the horizontal plane, wherein on the inclined surface 1054 There is a probe substrate positioning groove 1052 for loading the probe substrate 103. The probe substrate positioning groove is square and matches the shape of the probe substrate; the convex parts on both sides of the probe substrate positioning groove 1052 On 1053, there is a clamping tool positioning groove 1051 in the middle part that is convenient for the operation of the clamping tool (such as tweezers). The clamping tool positioning groove 1051 can be semicircular; One end of the slot is sealed to prevent the inserted probe from slipping. After the probe substrate is loaded into the probe substrate positioning groove 1052, the semicircular positioning grooves on both sides for the tweezers to operate are just located on both sides of the middle of the probe substrate.

During manufacture, using metal such as aluminum alloy or stainless steel as the processing material, two planes (plane 1054 and 1055), and the remaining planes are kept in vertical or horizontal direction; among which planes 1054 and 1056 require higher surface roughness for machining than other planes because they involve probe fixation and piezoelectric ceramic block bonding respectively. The plane 1054 is used to further process the positioning groove for placing the probe; a small size milling cutter is used to machine a probe positioning groove with a depth of 0.5mm and a width of about 2mm on this plane, and semicircular positioning with the same depth is machined on both sides of the groove The groove 1051 (about 1mm in diameter) is used to facilitate the operation of the tweezers, and the 0.5mm thick material is also removed from the track coverage area operated by the milling cutter (see Figure 7). The end of the probe groove is bonded to a blocking sheet 104 with the same thickness as the groove depth.

The method of using the probe clamping and fixing device is as follows: first, remove the device base fixed by the magnetic attraction method from the main body of the instrument and turn it over to place the bottom surface upward; adjust the position of the pressing slide 102 to the probe groove 1052 All are exposed to the field of view; use tweezers to clamp the middle section of the probe substrate, place the probe substrate in the probe groove and make fine adjustments. Since the semicircular groove reserved for the operation of the tweezers is located in the middle section of the probe substrate, the tweezers can always operate the middle section of the probe substrate during placement and adjustment, avoiding the need to operate due to the structural limitation of the clamping device. Other parts of the substrate (eg: only at the front or back end) are prone to human-caused probe damage. Then lift the forward pressing portion 1021 of the pressing slide and push the pressing slide 102 forward, so that the position of the forward pressing portion 1021 is just on the probe substrate; lower the forward pressing portion 1021 to press and fix the probe 103, so that the probe substrate is well fixed.

In addition, as shown in FIG. 6 , the edge of the clamping base 101 may have an inclination angle, and the inclination angle is the same as the second angle B. As shown in FIG. According to an embodiment of the present invention, the second inclination angle is greater than 45 degrees and less than 75 degrees. At the same time, the difference between the first angle A and the third angle C should be greater than or equal to 3 degrees and less than or equal to 5 degrees, and at the same time B/(A-C) should be between 15 and 25. The technical solution can not only ensure the normal operation of the probe, but also facilitate the clamping of the probe substrate.

Figure 9 compares the differences when the tweezers operate the probe substrate at different positions. For example, in order to use the dome-type probe holding device to fix the substrate, the front end of the substrate is usually clamped during operation with tweezers; Closer, there is a greater possibility of artificial needle tip damage caused by operational errors. In another way, although there is space reserved for the clamping tool in the positioning groove of the probe substrate, the tweezers can only operate the end of the substrate, while the edge of the common AFM probe substrate has chamfered edges, and only the substrate can be manipulated. The end of the clamp is easy to cause an unstable state of clamping.

It should be noted that each angle value herein does not exclude various machining errors during manufacture.

The clamping and fixing device of the atomic force microscopy probe according to the embodiment of the present invention has one or more of the following advantages and positive effects: the lever-type pressure-sliding sheet structure is used as the clamping device of the AFM probe, and during operation The pressing end of the pressing slide can be completely removed from the probe groove, and the probe positioning groove can be completely exposed to the operator's field of vision, which is convenient for the operation of loading the probe substrate; when using a clamping tool (such as tweezers) During operation, the semicircular positioning groove reserved for tweezers is located in the middle of the probe substrate, which makes it easier for the operator to put in and take out the substrate; the magnetic fixed base can make the operation easier. The user can directly load or take out the holding device with the probe without other tools, and at the same time avoid the structural wear caused by the mechanical insertion method. These measures make manual placement and automated placement of probes more convenient and reliable, and reduce unnecessary losses caused by operations during loading of AFM probes.

It should be noted that the described embodiments are only some, but not all, embodiments of the present invention. Based on the concept of the present invention, any other embodiments within the scope of the claims of the present invention belong to the protection scope of the present invention.

Claims (8)

1. The atomic force microscopy probe clamping device is characterized by comprising a probe base, wherein the probe base is used for mounting a probe substrate, the probe base is provided with a first inclined plane and a second inclined plane which respectively form a first included angle and a second included angle with the horizontal plane, the first included angle is smaller than the second included angle, and a probe substrate positioning groove for loading the probe substrate is formed in the first inclined plane; clamping tool positioning grooves are formed in the two sides of the probe substrate positioning groove; after the probe substrate is arranged in the probe substrate positioning groove, the clamping tool positioning groove is positioned at two sides of the middle part of the probe substrate, and a blocking piece is arranged at the tail end of the probe substrate positioning groove and used for preventing the probe substrate from sliding off, wherein the blocking piece is bonded with the probe base, and the clamping tool positioning groove is not arranged at two sides of the end part of the probe substrate positioning groove;

wherein, the probe substrate positioning groove is processed on the first inclined plane by a milling cutter, the same thickness of material is removed from the track coverage area operated by the milling cutter, the clamping tool positioning grooves with the same depth are processed on the two sides of the probe substrate positioning groove, then the barrier sheet with the same thickness as the groove depth of the probe substrate positioning groove is bonded at the tail end of the probe substrate positioning groove,

the atomic force microscopy probe clamping device further comprises a clamping base and a pressing and sliding assembly; the sliding pressing component comprises a spring, a fixed screw piece and a sliding pressing piece, the sliding pressing piece is provided with a main body part, a sliding hole part and a front extension part,

the edge of the clamping base has an inclination angle which is the same as the second included angle,

the forward extending portion forms a third included angle with the body portion, the third included angle being smaller than the first included angle,

the ratio of the second included angle to the difference between the first included angle and the third included angle is more than 15 and less than 25, the difference between the first included angle and the third included angle is more than or equal to 3 degrees and less than or equal to 5 degrees,

wherein the second included angle is greater than 45 degrees and less than 75 degrees.

2. The atomic force microscopy probe clamping device as claimed in claim 1, wherein the clamping tool positioning groove comprises two semicircular grooves, the blocking piece is a metal piece or a ceramic piece, and the thickness of the blocking piece is the same as the groove depth of the probe substrate positioning groove;

the clamping base comprises a spring accommodating hole, a threaded hole and a probe base mounting part, and the front extension part is a metal sheet;

one end of the spring is arranged in the spring accommodating hole, the body part is arranged at the other end of the spring and used for pressing the spring, and the fixing screw piece penetrates through the sliding hole part and is connected with the threaded hole, so that the pressing sliding piece and the spring are arranged on the clamping base and can push the body part, and the forward extending part can move back and forth by utilizing the sliding hole part;

the probe base is installed on the probe base installation part, when the forward extension part moves to the front part, the forward extension part presses the probe substrate arranged on the probe base, and when the forward extension part moves to the rear part, the probe substrate is released.

3. The atomic force microscopy probe clamping device of claim 2, wherein the second included angle is 60 degrees, the first included angle is 15 degrees, and the third included angle is 12 degrees.

4. The atomic force microscopy probe clamping device of claim 2 wherein a piezoelectric ceramic block is disposed between the probe base and the probe base mounting portion; the spring is a pressure spring, the spring accommodating hole is a blind hole, and a through hole convenient for installation is formed in the tail end of the blind hole; the clamping tool positioning groove is semicircular, and the probe substrate positioning groove is square.

5. The atomic force microscopy probe clamping device according to claim 2, further comprising a probe holder fixing base, wherein the clamping base is provided with at least two connecting holes, the probe holder fixing base is provided with corresponding screw holes, and the probe holder fixing base and the clamping base are fixedly connected through the connecting holes and the screw holes.

6. The atomic force microscopy probe clamping device as claimed in claim 5, wherein the probe holder fixing base has three positioning points, each positioning point comprises two positioning pin grooves and a round hole, the difference between each adjacent group of positioning pin grooves is 120 degrees, and each positioning pin groove is provided with a positioning pin.

7. The atomic force microscopy probe clamping device as claimed in claim 5, wherein the two connecting holes are provided with a gap part near the edge of the base body.

8. The atomic force microscopy probe clamping device as claimed in claim 5, wherein the probe holder fixing base is provided with two magnet slots, the magnet slots are cylindrical blind holes, magnets are arranged in the magnet slots, and the tail ends of the blind holes are provided with through holes convenient for installation.

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