Micro-core fine machining grinding device and core preparation method

Abstract

The present application relates to the technical field of sampling, in particular to a micro-core fine processing grinding device and a core preparation method, the micro-core fine processing grinding device comprises a clamping module and a power module, the clamping module comprises a chuck and a clamping jaw movably arranged on the end face of the chuck, the clamping jaw is used for clamping one end of a core sample, the clamping module further comprises three sanding rollers uniformly and spacedly arranged on the periphery of the clamping jaw, the periphery of the three sanding rollers is used for clamping the core sample and polishing the outer circumferential surface of the core sample, the power module is used for driving connection with the three sanding rollers, and the sanding rollers are driven to rotate to polish the outer circumferential surface of the core sample, and the power module and the three sanding rollers can be connected and disconnected. The present application solves the technical problems that the core sample is easy to break during polishing in the prior art, and the diameter of the polished core sample is large, which affects the scanning precision.

Description

Technical Field

[0001] This invention relates to the field of sampling technology, specifically to a micro-core fine processing grinding device and a core preparation method. Background Technology

[0002] In oil exploration and development, it is common practice to drill for formation rock samples and prepare cores of different sizes for analysis of reservoir mineral composition and rock properties. CT scanning core analysis technology is a technique developed in recent years. It can digitally reconstruct the three-dimensional structural features of pore throats through scanned images, and conduct reservoir microstructure analysis and seepage simulation based on the reconstructed data. The resolution of CT scans directly depends on the sample size; the smaller the diameter of the core sample, the higher the scanning accuracy, meaning the finer the pore throat structure that can be resolved.

[0003] Existing microcore preparation devices or methods are prone to breakage or fracture during the preparation of millimeter-scale microcores, or their size and shape do not meet the requirements for core CT scanning. For example, a microcore sample grinding device disclosed in Chinese invention patent application CN115056091A includes a chuck, a pin, and a diamond grinding disc. The rock sample is clamped and fixed between the chuck and the pin. The rotation of the chuck causes the rock sample to rotate, and the diamond grinding disc grinds the core sample from one side. Since the diameter of the ground core sample is often relatively small, and the core sample is unsupported, grinding from one side with the diamond grinding disc easily leads to core sample breakage. Moreover, to avoid core sample breakage, the ground core sample is often not small enough, which affects the accuracy of CT scanning. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention proposes a micro-core fine processing grinding device and core preparation method to solve the technical problems in existing technologies, such as the easy occurrence of core sample breakage during grinding and the large diameter of the ground core sample affecting scanning accuracy.

[0005] The present invention provides a micro-core fine machining grinding device and core preparation method, which adopts the following technical solution:

[0006] A micro-core fine processing grinding device and core preparation method include a grinding platform and a clamping module disposed on the grinding platform. The clamping module includes a chuck and jaws movably disposed on the end face of the chuck. The jaws are used to clamp one end of the core sample. The clamping module also includes three abrasive rollers evenly spaced around the jaws. The three abrasive rollers are parallel to each other and their axes extend in the left-right direction. The axis extension direction of the abrasive rollers is the same as the axis extension direction of the core sample clamped on the jaws. The outer periphery of the three abrasive rollers is used to clamp the core sample and grind the outer peripheral surface of the core sample. The chuck has three sliding blocks that move radially around the jaws. The three sliding blocks are evenly spaced around the circumference of the chuck. One end of each grinding roller is rotatably mounted on three sliding blocks. When the three sliding blocks move closer to each other radially along the chuck, they drive the three grinding rollers to move closer together to clamp the outer periphery of the core sample. The grinding platform is also equipped with a power module, which is used to drive the three grinding rollers to rotate and grind the outer periphery of the core sample. At least one of the power module and the clamping module can move in the left and right direction to engage and disengage between the power module and the three grinding rollers. When one end of the core sample is clamped by the chuck, the power module and the clamping module move closer together, and the power module is driven by the grinding rollers. When it is necessary to remove the core sample, the power module and the clamping module separate, and the power module is disconnected from the grinding rollers.

[0007] Furthermore, the power module includes a support frame, a rotary drive mechanism, a drive pulley, and three transmission pulleys. The rotary drive mechanism is mounted on the support frame, and the three transmission pulleys are arranged in an equilateral triangle and correspond one-to-one with the three grinding rollers. The rotary drive mechanism is connected to the drive pulley, and the drive pulley is connected to the three transmission pulleys simultaneously via the same transmission belt. When the power module and the clamping module approach each other, the end of each grinding roller away from the chuck is inserted into and engaged with the end of the corresponding transmission pulley, preventing rotation. When the power module and the clamping module separate, the end of each grinding roller away from the chuck is disconnected from the corresponding transmission pulley.

[0008] Furthermore, two of the three drive pulleys have the same outer diameter, namely the first pulley and the second pulley, and the third pulley has an outer diameter larger than the first and second pulleys. The first and second pulleys are located below the third pulley. When the drive pulley drives the three drive pulleys to rotate via the drive belt, the rotational speed of the first and second pulleys is greater than that of the third pulley. This results in the rotational speed of the sand grinding roller connected to the third pulley being less than the rotational speed of the sand grinding rollers connected to the first and second pulleys respectively. When the three sand grinding rollers approach each other and clamp the core sample... After the core sample is removed from the outer circumference, the gripper releases its grip on the core sample. Two grinding rollers, which are respectively connected to the first and second pulleys, drive the core sample to rotate. A grinding roller connected to the third pulley rotates relative to the core sample to grind it. The outer circumferential surfaces of the three grinding rollers all have a grinding layer with different mesh counts. The grinding precision of the three grinding rollers on the core sample is different. When the chuck is rotated, the circumferential position of the three grinding rollers can be switched, so that the three grinding rollers are respectively connected to different drive pulleys.

[0009] Furthermore, the micro-core fine processing grinding device includes a circumferentially enclosed isolation cabinet. Inside the isolation cabinet is a central partition that divides the internal space of the entire isolation cabinet into upper and lower chambers. The upper chamber is the grinding chamber, and the upper side of the central partition forms the grinding platform. The clamping module and the power module are mounted on the central partition. The core sample to be ground is ground in the grinding chamber. The lower chamber is the dust collection chamber, which contains a vacuum cleaner. A dust baffle is located on one side of the power module, and a dust suction port is provided on the dust baffle. The vacuum cleaner is connected to the dust suction port on the dust baffle via a suction pipe. When grinding the core sample, the dust suction port faces the core sample to extract debris from its surface.

[0010] Furthermore, the power module includes a deformable bracket, which includes three connecting shafts. The axes of the three connecting shafts extend in the left-right direction and are respectively arranged in correspondence with the three grinding rollers. Three transmission pulleys are rotatably installed on the ends of each connecting shaft facing the grinding rollers. A guide rod is connected between each pair of adjacent connecting shafts. One end of the guide rod is fixedly connected to one of the two adjacent connecting shafts, and the other end is movably inserted into the other connecting shaft. The three guide rods form an equilateral triangle structure. A first compression spring is sleeved on each guide rod. The first compression spring presses against the two adjacent connecting shafts, so that the three connecting shafts are far apart from each other in the initial state.

[0011] Furthermore, the power module also includes a conical cylinder movably mounted on the support frame in the left-right direction. The axis of the conical cylinder extends in the left-right direction, with one end being a flared end and the other end being a constricted end. The flared end of the conical cylinder faces the chuck. A dovetail groove extending along the generatrix of the conical cylinder is formed on the inner wall of the conical cylinder. Three dovetail grooves are evenly spaced along the circumference of the conical cylinder. A dovetail block is fixed at the end of the three connecting shafts away from the transmission pulley. Each dovetail block is slidably installed in the corresponding dovetail groove. When the conical cylinder moves relative to the support frame in the left-right direction, the dovetail block moves along the extension direction of the dovetail groove, so that the three connecting shafts move closer to or further away from each other in the radial direction of the conical cylinder.

[0012] Furthermore, the support frame includes an upright frame and a support shaft that extends outward from the upright frame in the left-right direction. The conical cylinder is movably sleeved on the support shaft in the left-right direction. Three connecting shafts and three guide rods are located on the periphery of the support shaft. The power module also includes a telescopic drive mechanism. The telescopic drive mechanism has a telescopic shaft extending in the left-right direction. When the telescopic shaft extends, it pushes the conical cylinder toward the direction closer to the chuck, so that the three connecting shafts move closer to each other in the radial direction of the conical cylinder.

[0013] Furthermore, a push ring is guided through the upright frame in the left-right direction. One end of the push ring is in push contact with the constricted end of the tapered cylinder, and the other end is in push contact with the telescopic shaft. An axial tension spring is connected between the constricted end of the tapered cylinder and the upright frame. One end of the axial tension spring is connected to the constricted end of the tapered cylinder, and the other end is connected to the upright frame. When the telescopic shaft is shortened, the axial tension spring drives the tapered cylinder to move away from the chuck. The first compression spring drives the three connecting shafts to move away from each other radially along the tapered cylinder.

[0014] Furthermore, the push ring consists of multiple guide rods and two circular rings arranged symmetrically on the left and right sides. The two circular rings are located on the left and right sides of the upright frame, respectively. The multiple guide rods extend in the left and right direction and are evenly spaced along the circumference of the support shaft. The two ends of each guide rod are fixedly connected to the circular rings on the left and right sides, respectively. Each guide rod is guided through the upright frame in the left and right direction. One of the two circular rings is in push contact with the concave end of the conical cylinder, and the other is in push contact with the telescopic shaft of the telescopic drive mechanism.

[0015] Furthermore, the deformable bracket also includes a triangular plate with a through hole at its center. The triangular plate is mounted on the support shaft through the through hole. Three guide slots extending radially along the through hole are provided on the triangular plate around the periphery of the through hole. The guide slots are arranged one-to-one with the connecting shafts, and each connecting shaft is respectively inserted into the corresponding guide slot. The side wall of the connecting shaft is provided with a retaining groove that cooperates with the side wall of the triangular plate to prevent the triangular plate from moving axially along the connecting shaft.

[0016] Furthermore, the support shaft is movably mounted on the upright frame in the left-right direction. A second compression spring is sleeved on the support shaft. The second compression spring is located inside the conical cylinder. One end of the second compression spring contacts the inner wall of the conical cylinder's constricted end. A shoulder is provided on the side wall of the support shaft. The other end of the second compression spring contacts the shoulder. When the conical cylinder moves toward the chuck, the conical cylinder drives the support shaft to move toward the chuck via the second compression spring, so that the end of the support shaft facing the chuck fits against the end of the core sample, thereby preventing the core sample from moving toward the conical cylinder.

[0017] Furthermore, the support frame includes a limiting bracket and a lifting frame movably disposed in the limiting bracket in the vertical direction. The limiting bracket and the lifting frame are located below the transmission pulley. A lifting drive mechanism is provided below the lifting frame, and the rotation drive mechanism is disposed on the lifting frame. The drive pulley is rotatably mounted on the lifting frame. When the lifting frame moves up and down, the tension of the transmission belt is adjusted. When the transmission pulley separates from the sand grinding roller, the lifting frame rises to loosen the transmission belt, and the transmission belt separates from each transmission pulley. When the three sand grinding rollers approach each other and clamp the core sample, the lifting frame descends to tension the transmission belt and make it tightly fit with each transmission pulley. Tensioning wheels are rotatably disposed on opposite sides of the transmission belt on the limiting bracket. The two tensioning wheels are located above the drive pulley, and the distance between the two tensioning wheels is smaller than the outer diameter of the drive pulley.

[0018] Furthermore, a limiting ring is fixed on the periphery of the jaws on the chuck. The limiting ring is circumferentially spaced with three sliding grooves extending radially. The sliding blocks are respectively guided and installed in the corresponding sliding grooves. Each sliding groove is provided with a radial tension spring. One end of the radial tension spring is fixedly connected to the sliding block, and the other end is fixedly connected to the limiting ring. When each grinding roller is separated from the drive pulley, each radial tension spring drives the sliding block to move away from each other radially along the limiting ring, so that the three grinding rollers move away from each other.

[0019] Furthermore, the grinding platform is provided with a transverse slide rail extending in the left-right direction and a longitudinal slide rail extending in the front-back direction. A transverse slide block that moves in the left-right direction is guided on the transverse slide rail, and a longitudinal slide block that moves in the front-back direction is guided on the longitudinal slide rail. The clamping module is disposed on the transverse slide block, and the power module is disposed on the longitudinal slide block. The left-right movement of the transverse slide block causes the clamping module to move closer to or away from the power module, and the front-back movement of the longitudinal slide block causes the power module to be offset from or aligned with the clamping module in the front-back direction.

[0020] A method for preparing cores using the aforementioned micro-core fine processing grinding device includes the following steps:

[0021] a. Prepare core samples; select initial core samples that meet the length requirements, then select the target area by performing CT scanning on the initial core samples, and use a wire cutting tool to cut the part of the initial core sample containing the target area into columnar core samples with flat end faces at both ends.

[0022] b. First grinding of the core sample: The cylindrical core sample is inserted between the three grinding rollers of the clamping module. The jaws clamp one end of the core sample, fixing it on the chuck. The clamping module and the power module are close to each other and connected by transmission. The three grinding rollers are close to each other and clamp the outer circumference of the core sample. The power module drives the grinding rollers to rotate to grind the outer circumference of the core module. Grinding is performed on the core sample using grinding rollers with a grinding layer of 800 grit. The rotation speed of the rotary drive mechanism is set to 3000 rpm. The telescopic rod of the telescopic drive mechanism extends at the set speed, causing the conical cylinder to move towards the chuck at the set speed. The three grinding rollers move closer to the core sample radially at a feed speed of 0.05 mm / min, that is, the feed speed of the grinding rollers is 0.05 mm / min. The grinding feed amount for the entire first grinding is 2 mm.

[0023] c. Perform a second grinding on the core sample; use a grinding roller with a grinding layer of 1200 mesh to grind the core sample, set the rotation speed of the rotary drive motor to 2000 rpm, the grinding feed of the grinding roller to 2 mm, and the feed speed to 0.02 mm / min.

[0024] d. Perform a third grinding on the core sample; use a 2000-mesh grinding roller to grind the core sample, set the rotation drive motor speed to 2000 rpm, the grinding roller feed rate to 1 mm, and the feed speed to 0.01 mm / min.

[0025] The beneficial effects of this invention are as follows: The micro-core fine processing grinding device and core preparation method of this invention utilize grinding rollers arranged parallel to the core sample axis around the core sample. These grinding rollers support and grind the core sample, protecting it from breakage during grinding. This allows for more repeated grinding of the core sample, resulting in smaller diameter core samples. Furthermore, by setting different grinding grits on the three grinding rollers and switching between different rollers to grind the core sample, grinding efficiency is improved, and the device is more convenient to use.

[0026] This invention utilizes a vacuum cleaner to extract dust from one side of the core sample surface. This not only removes debris from the core sample surface but also uses air cooling to reduce heat buildup during grinding. Furthermore, it controls dust dispersion in terms of HSE (Health, Safety, and Environment), ensuring a healthy and safe working environment for staff.

[0027] The core samples prepared using the core preparation method of this invention achieve a voxel accuracy of 1.743 μm in a micron-CT system. The core preparation process requires manual operation only in the steps of adjusting grinding parameters and changing grinding heads; the rest of the process does not require personnel to be on duty. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Those skilled in the art should understand that these drawings are not necessarily drawn to scale.

[0029] Figure 1 This is a three-dimensional schematic diagram of an embodiment of a micro-core precision grinding device of the present invention;

[0030] Figure 2 This is a schematic diagram of a micro-core fine processing grinding device according to the present invention after removing the isolation cabinet and the vacuum cleaner;

[0031] Figure 3 This is a schematic diagram of the docking of the power module and the clamping module in one embodiment of the micro-core precision grinding device of the present invention (the outer shell of the power module is removed).

[0032] Figure 4 This is a schematic diagram of the power module and clamping module after separation in one embodiment of the micro-core fine machining grinding device of the present invention (power module with outer shell removed).

[0033] Figure 5 for Figure 3 The main view;

[0034] Figure 6 for Figure 5 Sectional view along line AA;

[0035] Figure 7 for Figure 5 Sectional view along the BB direction;

[0036] Figure 8 for Figure 3 Top view;

[0037] Figure 9 for Figure 8 CC-direction sectional view.

[0038] In the diagram: 1. Isolation cabinet; 2. Middle partition; 3. Vacuum cleaner; 4. External touch screen; 5. Lateral limiter; 6. Longitudinal limiter; 7. Dustproof baffle; 8. Rotary motor; 9. Telescopic drive mechanism; 10. Longitudinal slide; 11. Lateral slide; 12. Chuck; 13. Gripper; 14. Lateral slide rail; 15. Core sample; 17. Longitudinal slide rail; 19. Support frame; 20. Push ring; 201. Axial tension spring; 21. Stand; 22. Limiting frame; 23. Threaded shaft; 24. Lifting frame; 25. Rotary drive mechanism; 26. Drive pulley; 27. Transmission belt; 28. Third pulley; 29. ​​Guide link; 30. First compression spring; 32. Triangular plate; 33. Dovetail block; 34. Second pulley; 35. Conical cylinder; 36. Second compression spring; 37. Support shaft; 38. Grinding roller; 39. Sliding block; 40. Limiting ring; 50. Power module; 60. Clamping module. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] An embodiment of the micro-core fine machining grinding device and core preparation method of the present invention, such as... Figures 1 to 9 As shown, the micro-core fine processing grinding device includes a circumferentially enclosed isolation cabinet 1. Inside the isolation cabinet 1 is a central partition 2, which divides the interior of the cabinet 1 into upper and lower chambers. The upper chamber is the grinding chamber, where the core sample 15 to be ground is ground. The upper side of the central partition 2 forms a grinding platform. The lower chamber is the dust collection chamber, which contains a vacuum cleaner 3 connected to the grinding chamber via a dust collection pipe to absorb dust generated within the grinding chamber. An external touchscreen 4 is located on one side of the isolation cabinet 1, allowing operators to control the operation of the micro-core fine processing grinding device.

[0041] In this invention, the micro-core precision grinding device further includes a clamping module 60 and a power module 50 arranged in the grinding chamber of the isolation cabinet 1. In this embodiment, both the clamping module 60 and the power module 50 are movably mounted on the grinding platform. Specifically, the grinding platform is provided with a transverse slide rail 14 extending in the left-right direction and a longitudinal slide rail 17 extending in the front-back direction. A transverse slide block 11 that moves in the left-right direction is guided on the transverse slide rail 14, and a longitudinal slide block 10 that moves in the front-back direction is guided on the longitudinal slide rail 17. The clamping module 60 is mounted on the transverse slide 11, and the power module 50 is mounted on the longitudinal slide 10. The transverse slide 11 moves left and right, causing the clamping module 60 to move closer to or further away from the power module 50. The longitudinal slide 10 moves back and forth, causing the power module 50 to be offset from or aligned with the clamping module 60 in the front-back direction. When the clamping module 60 and the power module 50 are offset in the front-back direction, it helps to provide sufficient space for the clamping module 60 to install and remove the core sample 15. In this invention, the left end of the transverse slide rail 14 is connected to a transverse limiter 5, and the front end of the longitudinal slide rail 17 is connected to a longitudinal limiter 6. The transverse limiter 5 and the longitudinal limiter 6 are used to drive the transverse slide 11 and the longitudinal slide 10 to move a set distance, respectively. It should be noted that the transverse slide rail 14, the longitudinal slide rail 17, the transverse slide 11, the longitudinal slide 10, the transverse limiter 5, the longitudinal limiter 6, and the vacuum cleaner 3 are all existing known structures and will not be described in detail here.

[0042] In this invention, the clamping module 60 includes a chuck 12 and a jaw 13 movably disposed on the end face of the chuck 12. The jaw 13 is used to clamp one end of the core sample 15. The chuck 12 is rotatably disposed on the left end of the transverse slide 11, and a rotary motor 8 is provided on the right end of the transverse slide 11. The rotary motor 8 is connected to the chuck 12 to drive the chuck 12 to rotate. It should be noted that the rotary motor 8, the chuck 12, the jaw 13, and the connection and cooperation structure between the three are all existing structures and will not be described in detail here. The clamping module 60 also includes three abrasive rollers 38 evenly spaced around the jaw 13. The three abrasive rollers 38 are parallel to each other and their axes extend in the left-right direction. The direction of the extension of the axis of the abrasive rollers 38 is the same as the direction of the extension of the axis of the core sample 15 clamped on the jaw 13. The outer periphery of the three abrasive rollers 38 is used to clamp the core sample 15 and polish the outer peripheral surface of the core sample 15.

[0043] In this embodiment, a limiting ring 40 is fixed on the end face of the chuck 12 around the periphery of the jaws 13. The limiting ring 40 has three sliding grooves extending radially at intervals along its circumference. The three sliding grooves are arranged one-to-one with the three grinding rollers 38. A sliding block 39 is guided and movably installed in each sliding groove. There are three jaws 13 and three sliding blocks 39, which are evenly and alternately distributed along the circumference of the chuck 12. One end of each of the three grinding rollers 38 is rotatably mounted on the three sliding blocks 39. When the three sliding blocks 39 move closer to each other radially along the chuck 12, they drive the three grinding rollers 38 to move closer to each other to clamp the outer periphery of the core sample 15. When the three sliding blocks 39 move away from each other radially along the chuck 12, they drive the three grinding rollers 38 to move away from each other to release the core sample 15. In this embodiment, each groove is provided with a radial tension spring. One end of the radial tension spring is fixedly connected to the sliding block 39, and the other end is fixedly connected to the limiting ring 40. In the initial state, each radial tension spring drives the sliding block 39 to move away from each other along the radial direction of the limiting ring 40, so that the three sanding rollers 38 move away from each other.

[0044] The power module 50 is connected to the three grinding rollers 38 and drives the grinding rollers 38 to rotate to grind the outer periphery of the core sample 15. The transverse slide 11 drives the clamping module 60 to move left and right, so that the clamping module 60 and the power module 50 move closer or further apart, so that the power module 50 and the three grinding rollers 38 can be engaged or disengaged. When one end of the core sample 15 is clamped by the chuck 12, the power module 50 and the clamping module 60 move closer to each other, and the power module 50 is connected to the grinding rollers 38. When it is necessary to remove the core sample 15, the power module 50 and the clamping module 60 separate, and the power module 50 is disconnected from the grinding rollers 38.

[0045] In this embodiment, the power module 50 includes a housing and a support frame 19, a rotary drive mechanism 25, a drive pulley 26, and three transmission pulleys disposed within the housing. A dustproof baffle 7 is fixed to the outside of the housing, and a dust suction port is provided on the dustproof baffle 7. The vacuum cleaner 3 is connected to the dust suction port on the dustproof baffle 7 through a dust suction pipe. When grinding the core sample 15, the dust suction port faces the side of the core sample 15 to suck up debris from the surface of the core sample 15. The three transmission pulleys are arranged in an equilateral triangle and are respectively arranged in a one-to-one correspondence with the three sanding rollers 38. In this embodiment, the rotary drive mechanism 25 is a motor, which is mounted on the support frame 19. The rotary drive mechanism 25 is connected to the drive pulley 26, and the drive pulley 26 is connected to the three transmission pulleys simultaneously through the same transmission belt 27. When the power module 50 and the clamping module 60 approach each other, the end of each grinding roller 38 away from the chuck 12 is inserted into and anti-rotationally connected to the end of the corresponding transmission pulley. When the power module 50 and the clamping module 60 separate, the end of each grinding roller 38 away from the chuck 12 is disconnected from the corresponding transmission pulley. In this embodiment, a square hole is provided at the end of each grinding roller 38 away from the chuck 12, and a square shaft that fits into the square hole is provided at the end of each transmission pulley facing the grinding roller 38. In the initial state, the distance between the three transmission pulleys is the same as the distance between the three grinding rollers 38. Thus, when the clamping module 60 and the power module 50 are aligned and approach each other, the square shafts on the three transmission pulleys can be inserted into the square holes on the three grinding rollers, realizing the transmission connection between the power module 50 and the grinding rollers 38.

[0046] In this embodiment, to ensure that the spacing between the three drive pulleys matches the spacing between the three grinding rollers 38, i.e., the three drive pulleys can move closer to each other and further away from each other, the power module 50 further includes a tapered cylinder 35 movably mounted on the support frame 19 in the left-right direction, and a deformable bracket movably connected to the tapered cylinder 35. The deformable bracket includes three connecting shafts, the axes of which all extend in the left-right direction and are respectively arranged corresponding to the three grinding rollers 38. The three drive pulleys are rotatably mounted on the end of each connecting shaft facing the grinding roller 38. A guide rod 29 is connected between each pair of adjacent connecting shafts. One end of the guide rod 29 is fixedly connected to one of the two adjacent connecting shafts, and the other end is movably inserted into the other connecting shaft. The three guide rods 29 form an equilateral triangle structure. A first compression spring 30 is sleeved on each guide rod 29. The first compression spring 30 presses against the two adjacent connecting shafts, causing the three connecting shafts to move away from each other in the initial state. The axis of the conical cylinder 35 extends in the left-right direction, and one end of the conical cylinder 35 is a flared end and the other end is a constricted end. The flared end of the conical cylinder 35 faces the chuck 12. A dovetail groove extending along the generatrix of the conical cylinder 35 is provided on the inner wall of the conical cylinder 35. Three dovetail grooves are evenly spaced along the circumference of the conical cylinder 35. A dovetail block 33 is fixed at the end of the three connecting shafts away from the transmission pulley. Each dovetail block 33 is slidably installed in the corresponding dovetail groove. When the conical cylinder 35 moves in the left-right direction relative to the support frame 19, the dovetail block 33 moves along the extension direction of the dovetail groove so that the three connecting shafts move closer to each other or further away from each other in the radial direction of the conical cylinder 35.

[0047] Furthermore, the support frame 19 includes a vertical frame 21 and a support shaft 37 extending from the vertical frame 21 in the left-right direction. The conical cylinder 35 is movably sleeved on the support shaft 37 in the left-right direction. Three connecting shafts and three guide rods 29 are located on the periphery of the support shaft 37. The power module 50 also includes a telescopic drive mechanism 9, which is a telescopic cylinder. The telescopic cylinder has a fixed cylinder body and a telescopic shaft that extends and retracts in the left-right direction. The fixed cylinder body of the telescopic cylinder is fixed to the outer wall of the outer shell of the power module 50. When the telescopic shaft extends, it pushes the conical cylinder 35 towards the chuck 12, so that the three connecting shafts move closer to each other radially along the conical cylinder 35. When the telescopic shaft retracts, the conical cylinder 35 loses the pushing action of the telescopic cylinder, and the first compression spring 30 sleeved on the guide rod 29 drives the three connecting shafts away from each other. The dovetail blocks 33 on each connecting shaft slide along the dovetail groove.

[0048] Furthermore, in order to control the tension of the transmission belt 27 so as to make the three transmission pulleys approach and move away from each other, in this embodiment, the support frame 19 includes a limiting bracket and a lifting frame 24 that is movably arranged in the limiting bracket in the vertical direction. The limiting bracket and the lifting frame 24 are located below the transmission pulleys. A lifting drive mechanism is provided below the lifting frame 24. The rotation drive mechanism 25 is arranged on the lifting frame 24. The drive pulley 26 is rotatably mounted on the lifting frame 24. When the lifting frame 24 moves up and down, it adjusts the tension of the transmission belt 27. After the transmission pulleys separate from the sand grinding rollers 38, the lifting frame 24 rises to loosen the transmission belt 27, separating it from each transmission pulley. When the three sand grinding rollers 38 approach each other and clamp the core sample 15, the lifting frame 24 descends to tension the transmission belt 27 and tightly engage it with each transmission pulley. Tensioning wheels are rotatably mounted on opposite sides of the transmission belt 27 on the limiting bracket. The two tensioning wheels are located above the drive pulley 26, and the distance between the two tensioning wheels is less than the outer diameter of the drive pulley 26. In this embodiment, the lifting drive mechanism includes a threaded shaft 23 extending in the vertical direction. The threaded shaft 23 is threadedly engaged with the lifting frame 24. The lower end of the threaded shaft 23 is rotatably mounted on the bottom of the limiting frame 22. A lifting drive motor is located at the bottom of the limiting frame 22, and the lower end of the threaded shaft 23 is connected to the lifting drive motor. The bottom of the limiting frame 22 is provided with a guide shaft extending in the vertical direction on one side of the threaded shaft 23, and the guide shaft is guided and engaged with the lifting frame 24.

[0049] In this embodiment, a push ring 20 is guided through the upright frame 21 in the left-right direction, and the telescopic drive mechanism 9 pushes the conical cylinder 35 through the push ring 20. One end of the push ring 20 is in push contact with the constricted end of the conical cylinder 35, and the other end is in push contact with the telescopic shaft. An axial tension spring 201 is connected between the constricted end of the conical cylinder 35 and the upright frame 21. One end of the axial tension spring 201 is connected to the constricted end of the conical cylinder 35, and the other end is connected to the upright frame 21. When the telescopic shaft is shortened, the axial tension spring 201 drives the conical cylinder 35 to move away from the chuck 12, and the first compression spring 30 drives the three connecting shafts to move away from each other radially along the conical cylinder 35.

[0050] In this embodiment, the push ring 20 is composed of multiple guide rods and two circular rings arranged symmetrically on the left and right sides. The two circular rings are located on the left and right sides of the upright 21, respectively. The multiple guide rods extend in the left and right direction and are evenly spaced along the circumference of the support shaft 37. The two ends of each guide rod are fixedly connected to the circular rings on the left and right sides, respectively. Each guide rod is guided through the upright 21 in the left and right direction. One of the two circular rings is in push contact with the concave end of the tapered cylinder 35, and the other is in push contact with the telescopic shaft of the telescopic drive mechanism 9.

[0051] In this embodiment, the deformable bracket further includes a triangular plate 32. The center of the triangular plate 32 has a through hole, and the triangular plate 32 is mounted on the support shaft 37 through the through hole. Three guide slots extending radially along the through hole are provided on the periphery of the triangular plate 32. The guide slots are arranged one-to-one with the connecting shafts, and each connecting shaft is respectively inserted into the corresponding guide slot. The side wall of the connecting shaft is provided with a retaining groove that cooperates with the side wall of the triangular plate 32 to prevent the triangular plate 32 from moving axially along the connecting shaft.

[0052] In this embodiment, two of the three transmission pulleys have the same outer diameter, namely the first pulley and the second pulley 34, and the third pulley 28 has an outer diameter larger than the first and second pulleys 34. The first and second pulleys 34 are located below the third pulley 28. When the drive pulley 26 drives the three transmission pulleys to rotate via the transmission belt 27, the rotational speed of the first and second pulleys 34 is greater than the rotational speed of the third pulley 28. This results in the rotational speed of the sand grinding roller 38, which is connected to the third pulley 28, being less than the rotational speed of the sand grinding roller 38, which is connected to the first and second pulleys 34 respectively. In this invention, when the three sand grinding rollers 38 approach each other and clamp the outer periphery of the core sample 15, the gripper 13 releases the core sample 15, releasing the clamping effect on the core sample 15, allowing the core sample 15 to rotate with the rotation of the three sand grinding rollers 38. Specifically, among the three grinding rollers 38, the two grinding rollers 38 that are driven and connected to the first pulley and the second pulley 34 have a higher rotation speed, which results in a greater friction between these two grinding rollers 38 and the core sample 15. Thus, the two grinding rollers 38 that are driven and connected to the first pulley and the second pulley 34 can drive the core sample 15 to rotate around its own axis. The grinding roller 38 that is driven and connected to the third pulley 28 has a lower rotation speed, which will generate relative rotation with the core sample 15, thereby grinding the core sample 15.

[0053] In this embodiment, the outer circumferential surfaces of the three grinding rollers 38 all have a grinding layer, and the grit count of the grinding layer of the three grinding rollers 38 is different. That is, the grinding precision of the core sample 15 by the three grinding rollers 38 is different. In other words, the larger the grit count of the grinding layer, the finer the grinding of the outer circumference of the core sample 15 and the higher the grinding precision, and vice versa. In this embodiment, the grit counts of the grinding layers of the three grinding rollers 38 are 800 grit, 1200 grit, and 2000 grit, respectively. During use, after the transverse slide 11 drives the clamping module 60 to separate from the power module 50, the chuck 12 is rotated by the rotary motor 8. The rotation of the chuck 12 can switch the circumferential position of the three grinding rollers 38, so that the three grinding rollers 38 are respectively connected to different transmission pulleys. Since the grinding layer mesh count of the three grinding rollers 38 is different, after the different grinding rollers 38 are connected to the third pulley 28, they can grind the outer circumference of the core sample 15 with different precision. In this way, by switching different grinding rollers 38, the core sample 15 can be ground multiple times with different precisions.

[0054] During the grinding of the core sample 15, the gripper 13 will release the core sample 15. To prevent the core sample 15 from moving axially, in this embodiment, the support shaft 37 is movably mounted on the stand 21 in the left-right direction. A second compression spring 36 is sleeved on the support shaft 37. The second compression spring 36 is located inside the conical cylinder 35, with one end of the second compression spring 36 contacting the inner wall of the constricted end of the conical cylinder 35. A shoulder is provided on the side wall of the support shaft 37, and the other end of the second compression spring 36 contacts the shoulder. When the conical cylinder 35 moves towards the chuck 12, the conical cylinder 35 drives the support shaft 37 to move towards the chuck 12 via the second compression spring 36, causing the end of the support shaft 37 facing the chuck 12 to fit against the end of the core sample 15. By fitting the end of the core sample 15 against the support shaft 37, movement of the core sample 15 towards the conical cylinder 35 is prevented.

[0055] This invention utilizes the core preparation method of the aforementioned micro-core fine machining and grinding apparatus, wherein the micro-core fine machining and grinding apparatus is as follows: Figures 1 to 9 As shown, the core preparation method includes inserting a cylindrical core sample 15 between three abrasive rollers 38 of a clamping module 60. A jaw 13 clamps one end of the core sample 15, fixing it on a chuck 12. The clamping module and the power module 50 are close to each other and connected by a drive mechanism. The three abrasive rollers 38 are close to each other and clamp the outer periphery of the core sample 15. The power module 50 drives the abrasive rollers 38 to rotate, thus polishing the outer periphery of the core module. The specific steps are as follows:

[0056] a. Preparation of core sample 15. Select an initial core sample that meets the length requirements, and then select the target area by performing a CT scan on the initial core sample. Use a wire cutting tool to cut the part of the initial core sample containing the target area into a columnar core sample 15. The diameter of the core sample 15 is about 1 cm, and both ends of the core sample 15 are flat end faces.

[0057] b. First grinding of core sample 15. Initially, the clamping module 60 and the power module 50 are separated and offset in the front-to-back direction, as shown below. Figure 2 The core sample 15 is inserted between the three grinding rollers 38, and the gripper 13 clamps one end of the core sample 15. The rotary motor 8 drives the chuck 12 to rotate, so that the grinding roller 38 with a grinding layer of 800 grit is at the top, corresponding to the position of the third pulley 28. The position of the longitudinal slide 10 is adjusted through the external touch screen 4 to align the clamping module 60 and the power module 50. Then the position of the transverse slide 11 is adjusted so that the clamping module 60 carrying the core sample 15 is close to the power module 50, so that the grinding rollers 38 are connected to the drive pulleys respectively. Then the telescopic drive mechanism 9 is controlled to extend the telescopic shaft, pushing the conical cylinder 35 towards the chuck 12 until the outer circumference of the three grinding rollers 38 is in contact with the outer circumference of the core sample 15. The telescopic drive mechanism 9 then stops extending, and the lifting drive mechanism controls the lifting frame 24 to descend, so that the drive belt 27 is tensioned and connected to the three drive pulleys. Then, the gripper 13 releases the core sample 15, the vacuum cleaner 3 is started, the rotary drive mechanism 25 is activated, and its speed is set to 3000 rpm. The two lower grinding rollers 38 of the three grinding rollers rotate at the same speed, driving the core sample 15 to rotate at the same speed. The upper grinding roller 38 rotates at a lower speed than the two lower grinding rollers 38, and relative sliding occurs between it and the core sample 15, thereby grinding the outer circumference of the core sample 15. During the grinding process, the telescopic rod of the telescopic drive mechanism 9 extends at a set speed, causing the conical cylinder 35 to move towards the chuck 12 at a set speed, so that the three connecting shafts approach the core sample 15 radially at a feed speed of 0.05 mm / min, that is, the feed speed of the grinding rollers 38 is 0.05 mm / min, and the grinding feed amount for the entire first grinding is 2 mm.

[0058] c. Perform a second grinding on the core sample 15. After the first grinding is completed, control the rotary drive mechanism 25 to stop and control the lifting frame 24 to rise, so that the transmission belt 27 is released and the gripper 13 is controlled to clamp one end of the core sample 15. Then the telescopic drive mechanism 9 retracts, and after the conical cylinder 35 loses its pushing effect, under the action of the first compression spring 30 and the circumferential tension spring, the conical cylinder 35 moves away from the chuck 12. The three connecting shafts move away from the chuck 12 together with the conical cylinder 35, and at the same time move away from each other radially along the core sample 15. The transverse slide 11 drives the clamping component to move away from the power module 50. Then the rotary motor 8 drives the chuck 12 to rotate at a set angle, and switches the 1200-mesh grinding roller 38 to the upper position. Then the clamping module 60 and the power module 50 are reconnected and connected. In this step, the rotation speed of the rotary drive motor is set to 2000 rpm, the grinding feed of the grinding roller 38 is 2 mm, and the feed speed is 0.02 mm / min.

[0059] d. Perform a third grinding on core sample 15. Following the above steps (3), switch the 2000-mesh grinding roller 38 to the upper position, and then reconnect the clamping module 60 and the power module 50. In this step, the rotation speed of the rotary drive motor is set to 2000 rpm, the grinding feed of the grinding roller 38 is 1 mm, and the feed speed is 0.01 mm / min.

[0060] e. Following the above operation process, the core sample 15 can be ground for the fourth time by replacing the sand grinding roller 38 with a larger mesh size, or by grinding and polishing more times, and finally a slender columnar core with a diameter of 1.89 mm and a length of more than 3 cm can be prepared.

[0061] The core sample 15 prepared using the core preparation method of the present invention achieved a voxel accuracy of 1.743 μm in a micron-CT system. During the core preparation process, only the steps of adjusting grinding parameters and changing grinding heads require manual operation, and the rest of the process does not require personnel to be on duty.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A micro-core fine processing grinding device, comprising a grinding platform and a clamping module (60) disposed on the grinding platform, the clamping module (60) comprising a chuck (12) and a jaw (13) movably disposed on the end face of the chuck (12), the jaw (13) being used to clamp one end of a core sample (15), characterized in that, The clamping module (60) further includes three abrasive rollers (38) evenly spaced around the jaws (13). The three abrasive rollers (38) are parallel to each other and their axes extend in the left-right direction. The axis of the abrasive rollers (38) extends in the same direction as the axis of the core sample (15) clamped on the jaws (13). The outer periphery of the three abrasive rollers (38) is used to clamp the core sample (15) and polish the outer periphery of the core sample (15). The chuck (12) has three sliding blocks (39) on the periphery of the jaws (13) that move radially along the chuck (12). The three sliding blocks (39) move radially along the chuck (12). The three grinding rollers (38) are arranged evenly in the circumferential direction. One end of each roller is rotatably mounted on a sliding block (39). When the three sliding blocks (39) move closer to each other radially along the chuck (12), they drive the three grinding rollers (38) to move closer to each other to clamp the outer periphery of the core sample (15). The grinding platform is also equipped with a power module (50). The power module (50) is used to drive the three grinding rollers (38) and drive the grinding rollers (38) to rotate to grind the outer periphery of the core sample (15). At least one of the power module (50) and the clamping module (60) can move in the left and right direction so that the power module (50) can move in the left and right direction. The power module (50) and the clamping module (60) are engaged and disengaged. When one end of the core sample (15) is clamped by the chuck (12), the power module (50) and the clamping module (60) move closer to each other. The power module (50) is connected to the grinding roller (38) for transmission. When it is necessary to remove the core sample (15), the power module (50) and the clamping module (60) separate from each other, and the power module (50) is disconnected from the grinding roller (38) for transmission. The power module (50) includes a support frame (19), a rotary drive mechanism (25), an active pulley (26), and three transmission pulleys. The rotary drive mechanism (25) is set on the support frame. (19) On the three transmission pulleys, they are arranged in an equilateral triangle and are respectively arranged in correspondence with the three sanding rollers (38). The rotary drive mechanism (25) is connected to the drive pulley (26). The drive pulley (26) is connected to the three transmission pulleys simultaneously through the same transmission belt (27). When the power module (50) and the clamping module (60) approach each other, the end of each sanding roller (38) away from the chuck (12) is inserted and engaged with the end of the corresponding transmission pulley and is connected to prevent rotation. When the power module (50) and the clamping module (60) separate from each other, the end of each sanding roller (38) away from the chuck (12) is disconnected from the corresponding transmission pulley.Two of the three drive pulleys have the same outer diameter, namely the first pulley and the second pulley (34), and the third pulley (28) has an outer diameter larger than the first pulley and the second pulley (34). The first pulley and the second pulley (34) are located below the third pulley (28). When the drive pulley (26) drives the three drive pulleys to rotate through the drive belt (27), the rotational speed of the first pulley and the second pulley (34) is greater than the rotational speed of the third pulley (28), so that the rotational speed of the sand grinding roller (38) connected to the third pulley (28) is less than the rotational speed of the sand grinding roller (38) connected to the first pulley and the second pulley (34) respectively. When the three sand grinding rollers (38) approach each other and clamp the outer periphery of the core sample (15) The gripper (13) releases the core sample (15) from its grip. Two grinding rollers (38), respectively connected to the first and second pulleys (34), drive the core sample (15) to rotate. The grinding roller (38), connected to the third pulley (28), rotates relative to the core sample (15) to grind it. The outer circumferential surfaces of all three grinding rollers (38) have grinding layers, and the mesh counts of these layers are different. The grinding precision of the three grinding rollers (38) on the core sample (15) is different. Rotating the chuck (12) allows switching the circumferential positions of the three grinding rollers (38), enabling them to be connected to different drive pulleys.

2. The micro-core precision grinding device according to claim 1, characterized in that: The system includes a circumferentially enclosed isolation cabinet (1), with an internal partition (2) dividing the internal space of the isolation cabinet (1) into upper and lower chambers. The upper chamber is the grinding chamber, and the upper side of the partition (2) forms the grinding platform. The clamping module (60) and the power module (50) are mounted on the partition (2). The core sample (15) to be ground is placed in the grinding chamber. During the grinding process, the chamber located below the middle partition (2) is a dust collection chamber. A vacuum cleaner (3) is installed in the dust collection chamber. A dustproof baffle (7) is provided on one side of the power module. A dust suction port is opened on the dustproof baffle (7). The vacuum cleaner (3) is connected to the dust suction port on the dustproof baffle (7) through a dust suction pipe. When grinding the core sample (15), the dust suction port faces the side of the core sample (15) to suck up the debris on the surface of the core sample (15).

3. The micro-core precision grinding device according to claim 2, characterized in that: The power module (50) includes a deformable bracket, which includes three connecting shafts. The axes of the three connecting shafts extend in the left-right direction and are respectively arranged in correspondence with three sanding rollers (38). Three transmission pulleys are respectively rotatably installed on one end of each connecting shaft facing the sanding roller (38). A guide rod (29) is connected between each pair of adjacent connecting shafts. One end of the guide rod (29) is fixedly connected to one of the two adjacent connecting shafts, and the other end is movably inserted into the other connecting shaft. The three guide rods (29) form an equilateral triangle structure. A first compression spring (30) is sleeved on each guide rod (29). The first compression spring (30) presses against the two adjacent connecting shafts, so that the three connecting shafts are far apart from each other in the initial state.

4. The micro-core precision grinding device according to claim 3, characterized in that: The power module (50) also includes a conical cylinder (35) that is movably mounted on the support frame (19) in the left-right direction. The axis of the conical cylinder (35) extends in the left-right direction, and one end of the conical cylinder (35) is a flared end and the other end is a constricted end. The flared end of the conical cylinder (35) faces the chuck (12). A dovetail groove extending along the generatrix of the conical cylinder (35) is provided on the inner wall of the conical cylinder (35). Three dovetail grooves are evenly spaced along the circumference of the conical cylinder (35). A dovetail block (33) is fixed at the end of the three connecting shafts away from the transmission pulley. Each dovetail block (33) is slidably mounted in the corresponding dovetail groove. When the conical cylinder (35) moves relative to the support frame (19) in the left-right direction, the dovetail block (33) moves along the extension direction of the dovetail groove so that the three connecting shafts move closer to each other or further away from each other in the radial direction of the conical cylinder (35).

5. The micro-core precision grinding device according to claim 4, characterized in that: The support frame (19) includes a stand (21) and a support shaft (37) that extends outward along the left and right direction on the stand (21). The conical cylinder (35) is movably sleeved on the support shaft (37) in the left and right direction. Three connecting shafts and three guide rods (29) are located on the periphery of the support shaft (37). The power module (50) also includes a telescopic drive mechanism (9). The telescopic drive mechanism (9) has a telescopic shaft that extends in the left and right direction. When the telescopic shaft is extended, it pushes the conical cylinder (35) toward the direction closer to the chuck (12) so that the three connecting shafts move closer to each other in the radial direction of the conical cylinder (35).

6. The micro-core precision grinding device according to claim 5, characterized in that: A push ring (20) is provided on the upright frame (21) along the left and right direction. One end of the push ring (20) is in push contact with the concave end of the conical cylinder (35), and the other end is in push contact with the telescopic shaft. An axial tension spring (201) is connected between the concave end of the conical cylinder (35) and the upright frame (21). One end of the axial tension spring (201) is connected to the concave end of the conical cylinder (35), and the other end is connected to the upright frame (21). When the telescopic shaft is shortened, the axial tension spring (201) drives the conical cylinder (35) to move away from the chuck (12). The first compression spring (30) drives the three connecting shafts to move away from each other along the radial direction of the conical cylinder (35).

7. The micro-core precision grinding device according to claim 6, characterized in that: The push ring (20) consists of multiple guide rods and two circular rings arranged symmetrically on the left and right sides. The two circular rings are located on the left and right sides of the upright frame (21). The multiple guide rods extend in the left and right direction and are evenly spaced along the circumference of the support shaft (37). The two ends of each guide rod are fixedly connected to the circular rings on the left and right sides respectively. Each guide rod is guided through the upright frame (21) in the left and right direction. One of the two circular rings is in push contact with the concave end of the conical cylinder (35), and the other is in push contact with the telescopic shaft of the telescopic drive mechanism (9).

8. The micro-core precision grinding device according to claim 5, characterized in that: The deformable bracket also includes a triangular plate (32), which has a through hole in its center. The triangular plate (32) is mounted on the support shaft (37) through the through hole. Three guide slots extending radially along the through hole are provided on the triangular plate (32) around the through hole. The guide slots are provided in correspondence with the connecting shafts. Each connecting shaft is respectively installed in the corresponding guide slot. The side wall of the connecting shaft is provided with a retaining groove that cooperates with the side wall of the triangular plate (32). The retaining groove prevents the triangular plate (32) from moving axially along the connecting shaft.

9. The micro-core precision grinding device according to claim 5, characterized in that: The support shaft (37) is movably mounted on the upright frame (21) in the left-right direction. A second compression spring (36) is sleeved on the support shaft (37). The second compression spring (36) is located inside the conical cylinder (35). One end of the second compression spring (36) contacts the inner wall of the conical cylinder (35) at the constricted end. A shoulder is provided on the side wall of the support shaft (37). The other end of the second compression spring (36) contacts the shoulder. When the conical cylinder (35) moves toward the chuck (12), the conical cylinder (35) drives the support shaft (37) to move toward the chuck (12) through the second compression spring (36), so that one end of the support shaft (37) toward the chuck (12) fits against the end of the core sample (15) to prevent the core sample (15) from moving toward the conical cylinder (35).

10. The micro-core precision grinding device according to claim 5, characterized in that: The support frame (19) includes a limiting bracket and a lifting frame (24) that is movably disposed in the limiting bracket in the vertical direction. The limiting bracket and the lifting frame (24) are located below the transmission pulley. A lifting drive mechanism is provided below the lifting frame (24). The rotary drive mechanism (25) is disposed on the lifting frame (24). The drive pulley (26) is rotatably mounted on the lifting frame (24). When the lifting frame (24) moves up and down, the tension of the transmission belt (27) is adjusted. When the transmission pulley separates from the grinding roller (38)... The lifting frame (24) rises to loosen the transmission belt (27), and the transmission belt (27) separates from each transmission pulley. When the three sand grinding rollers (38) approach each other and clamp the core sample (15), the lifting frame (24) descends to tension the transmission belt (27) and make it fit tightly against each transmission pulley. Tensioning wheels are respectively provided on the limiting bracket on the opposite sides of the transmission belt (27). The two tensioning wheels are respectively located above the driving pulley (26), and the distance between the two tensioning wheels is smaller than the outer diameter of the driving pulley (26).

11. The micro-core precision grinding device according to claim 5, characterized in that: A limiting ring (40) is fixed on the chuck (12) around the jaw (13). The limiting ring (40) is provided with three sliding grooves extending radially at circumferential intervals. The sliding blocks (39) are respectively guided and installed in the corresponding sliding grooves. Each sliding groove is provided with a radial tension spring. One end of the radial tension spring is fixedly connected to the sliding block (39), and the other end is fixedly connected to the limiting ring (40). When each sanding roller (38) is separated from the transmission pulley, each radial tension spring drives the sliding block (39) to move away from each other radially along the limiting ring (40), so that the three sanding rollers (38) move away from each other.

12. The micro-core precision grinding device according to claim 5, characterized in that: The grinding platform is provided with a transverse slide rail (14) extending in the left-right direction and a longitudinal slide rail (17) extending in the front-back direction. A transverse slide block (11) that moves in the left-right direction is guided on the transverse slide rail (14), and a longitudinal slide block (10) that moves in the front-back direction is guided on the longitudinal slide rail (17). The clamping module (60) is set on the transverse slide block (11), and the power module (50) is set on the longitudinal slide block (10). The transverse slide block (11) moves left and right, causing the clamping module (60) to move closer to or away from the power module (50). The longitudinal slide block (10) moves back and forth, causing the power module (50) to be offset from or aligned with the clamping module (60) in the front-back direction.

13. A method for preparing a core using the micro-core fine processing grinding apparatus according to any one of claims 4-12, characterized in that: The process includes the following steps: a) preparing core samples (15); selecting initial core samples that meet the length requirements, then selecting the target area by performing a CT scan on the initial core samples, and using a wire cutting tool to cut the part of the initial core sample containing the target area into a columnar core sample (15), with both ends of the core sample (15) being flat end faces. b. First grinding of core sample (15): Insert the cylindrical core sample (15) between the three grinding rollers (38) of the clamping module (60). The jaws (13) clamp one end of the core sample (15), fixing the core sample (15) on the chuck (12). The clamping module and the power module (50) are close to each other and connected by transmission. The three grinding rollers (38) are close to each other and clamp the outer periphery of the core sample (15). The power module (50) drives the grinding rollers (38) to rotate to grind the outer periphery of the core module. Use a grinding layer of 800. The purpose of the grinding roller is to grind the core sample (15). The rotation speed of the rotary drive mechanism (25) is set to 3000 rpm. The telescopic rod of the telescopic drive mechanism (9) extends at a set speed, so that the conical cylinder (35) moves towards the chuck (12) at a set speed, so that the three grinding rollers (38) approach the core sample (15) radially at a feed speed of 0.05 mm / min. That is, the feed speed of the grinding rollers (38) is 0.05 mm / min, and the grinding feed amount of the entire first grinding is 2 mm. c. Grind the core sample (15) for the second time; use a grinding roller with a grinding layer of 1200 mesh to grind the core sample (15), set the rotation speed of the rotary drive motor to 2000 rpm, the grinding feed of the grinding roller (38) to 2 mm, and the feed speed to 0.02 mm / min. d. Grind the core sample (15) for the third time. Use a grinding roller with a grinding layer of 2000 mesh to grind the core sample (15). Set the rotation speed of the rotary drive motor to 2000 rpm, the grinding feed of the grinding roller (38) to 1 mm, and the feed speed to 0.01 mm / min.

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