End face metallographic grinding clamping device for small-diameter metal rod

Abstract

The application provides a fine-diameter metal rod end face metallographic polishing clamping device, and belongs to the technical field of metallographic sample preparation. The device adopts a split and matched main body structure, mainly comprising a clamping device main body and a clamping mechanism. The clamping device main body is composed of two parts and is provided with a through clamping hole at the center position for placing a fine columnar metal sample. The clamping mechanism is composed of two pairs of M4 inner hexagonal cylindrical head bolts and matched embedded M4 hexagonal nuts. By symmetrically tightening the bolts, uniform and controllable clamping force can be applied to the sample in the hole, and stable centering and fixing are realized. An elastic shockproof pad is arranged on the sample clamping interface of the device, which can effectively buffer the polishing vibration and avoid rigid pressure injury on the sample surface. A spring washer is arranged on the contact end surface of the bolt and the device, which is used for dispersing the contact pressure and inhibiting the bolt loosening caused by polishing vibration. The application can structurally ensure that the sample polishing end face is highly parallel to the polishing disc surface, significantly improve the flatness precision and batch consistency of the metallographic sample preparation, effectively avoid the safety risk of sample flying out, and has the advantages of simple structure, convenient clamping, strong adaptability, and can be used with various manual and automatic metallographic polishing equipment.

Description

Technical Field

[0001] This invention relates to the field of metallographic sample preparation technology, and to a special clamping device for metallographic end face grinding of small-diameter rod-shaped metal materials. It can be widely used in the metallographic testing sample preparation process of metal materials in fields such as metallurgical engineering, materials science and engineering, mechanical manufacturing, aerospace, new energy materials, and medical devices. It is especially suitable for the end face metallographic sample preparation grinding and polishing process of small-diameter metal rods and samples. Background Technology

[0002] Metallographic analysis is a core method for performance testing, quality control, and failure analysis of metallic materials. Grinding and polishing are key steps in metallographic sample preparation, and the rationality of the clamping method directly determines the sample preparation accuracy, efficiency, and operational safety. Currently, for samples such as small-diameter metal rods, due to their small size and limited clamping area, end-face grinding remains a challenge in sample preparation. Existing technologies generally have the following shortcomings:

[0003] Firstly, manual sample preparation involves large errors and low efficiency. Operators rely solely on their hands to control the sample angle, making it difficult to ensure that the end face remains parallel to the grinding disc. Tilting the end face directly causes uneven focusing during microscopic observation, affecting the accuracy of quantitative measurements. Furthermore, due to the small overall size of the sample, it is prone to slipping out of the hand during high-speed polishing, posing a safety hazard.

[0004] Secondly, the mounting method has poor sample preparation accuracy and high overall cost. During the mounting process, the sample is prone to shifting and tilting, making it impossible to guarantee the perpendicularity of the end face; during grinding, the difference in hardness between the mounting material and the metal can easily cause chamfering of the sample edges, affecting the observation of edge microstructure, and the consumable cost is also high in the long term.

[0005] Third, the existing general-purpose clamping devices lack adaptability. Most devices use fixed holes with single-sided bolts for tightening, which can easily cause the sample to tilt or become eccentric. Furthermore, the fixed hole diameter cannot be continuously adapted to small rods of different diameters. Some split-type clamps have uneven locking force and poor alignment accuracy, which can easily cause the sample to misalign or deform.

[0006] In summary, existing technologies cannot simultaneously meet the requirements of clamping accuracy, stability, and efficiency for grinding the end faces of small rods. Therefore, it is necessary to design a metallographic grinding clamping device for the end faces of small-diameter metal rods to solve the above problems. Summary of the Invention

[0007] To address the aforementioned issues, a metallographic grinding clamping device for the end face of small-diameter metal rods was designed. This device solves the problem of accurate centering and clamping of small rod samples, ensures the parallelism of the end face grinding, and enhances the controllability of the clamping force, shock absorption, and anti-loosening performance of the device. This improves sample preparation quality and efficiency while reducing operational safety risks.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A metallographic grinding clamping device for the end face of a small-diameter metal rod includes a clamping device body and a clamping mechanism.

[0010] The main body of the clamping device is composed of a first clamping component and a second clamping component that fit together. The mating surfaces of the two components are precision-machined flat, resulting in no obvious gaps after fitting. Semi-cylindrical grooves are machined at the center of the mating surfaces of the two components, forming a through-hole central clamping hole after fitting, used to hold small rod samples. The axis of the clamping hole is perpendicular to the bottom surface of the device, structurally ensuring that the grinding end face of the sample is parallel to the surface of the polishing disc.

[0011] The inner wall of the central clamping hole is provided with an elastic shock-absorbing pad. The shock-absorbing pad is made of wear-resistant elastic polymer material, which can fill the tiny gap between the sample and the hole, evenly distribute the clamping force, avoid rigid clamping from scratching or crushing the sample surface, and also buffer the high-frequency vibration during the grinding process to reduce vibration marks and chatter marks on the sample surface.

[0012] The clamping mechanism includes two sets of symmetrically arranged M4 hexagon socket head cap screws and matching M4 hexagon nuts. The outer surface of the first clamping component has two hexagonal grooves into which the M4 hexagon nuts are embedded, achieving circumferential anti-rotation and axial positioning, eliminating the need for additional nut fixing during tightening. The corresponding position of the second clamping component has a countersunk bolt through-hole, through which the bolt passes to form a threaded engagement with the nut. When the bolts are tightened, the two clamping components smoothly approach each other along the mating direction, uniformly reducing the inner diameter of the clamping holes, applying a symmetrical and controllable clamping force to the sample, achieving stable centering and fixation.

[0013] Furthermore, a spring washer is provided between the head of the M4 socket head cap screw and the countersunk end face. On the one hand, it can disperse the contact pressure of the bolt head and protect the contact surface of the device from crushing and deformation. On the other hand, it can use elastic tension to offset the loosening torque caused by vibration, prevent the bolt from loosening on its own during the grinding process, and maintain the clamping stability during long-term operation.

[0014] The specific operating steps of this device are as follows:

[0015] (1) Sample preparation: Cut a small rod sample of appropriate length and remove the end face burrs and cutting deformation layer in advance;

[0016] (2) Device pre-assembly: Insert the M4 hexagonal nut into the groove of the first clamping component, and pass the bolt through the through hole of the second clamping component and pre-tighten the nut so that the two components are kept in a slightly taut state;

[0017] (3) Clamping the sample: Place the sample into the central clamping hole and adjust the axial position so that the end face to be ground protrudes slightly from the bottom surface of the device;

[0018] (4) Symmetrical locking: Tighten the two internal hex bolts alternately and evenly, and control the tightening force according to the material and size of the sample to ensure that the sample is firmly clamped and does not move.

[0019] (5) Grinding and polishing operation: Place the device stably on the grinding and polishing equipment, and complete the rough grinding, fine grinding and polishing processes according to the standard process;

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] First, it offers high clamping and positioning accuracy. The split-type mating structure with symmetrical locking ensures centered clamping of the sample, with the clamping holes perpendicular to the bottom surface of the device. This effectively reduces end-face tilting errors, guarantees the parallelism between the sample grinding end face and the polishing disc surface, and improves sample preparation accuracy and subsequent testing accuracy.

[0022] Secondly, the clamping force is highly controllable. It uses fine-thread internal hex bolts for locking, and the clamping force can be adjusted linearly and delicately, which can be flexibly controlled according to the hardness and size of the sample. With the help of elastic anti-vibration pads to disperse pressure, it can avoid indentation and plastic deformation on the sample surface, and is suitable for various soft and hard metal rods.

[0023] Third, it has good anti-vibration and anti-loosening effects. The anti-vibration pad can absorb the high-frequency vibration during the grinding process, reduce vibration marks and chatter marks on the sample surface, improve surface smoothness, and reduce the amount of subsequent polishing work; the spring washer can suppress bolt loosening caused by vibration and ensure clamping stability during long-term grinding.

[0024] Fourth, it has a wide range of applications and is easy to operate. The split clamping holes have a certain diameter adjustment margin, which can be used to fit samples of similar specifications, making it more versatile; the device only requires the operation of two bolts to install and remove samples, making the process simple and easy to learn, which can greatly improve sample preparation efficiency and reduce the labor intensity of operators.

[0025] Fifth, it offers high operational safety. The sample is completely enclosed within the device, and with a reliable anti-loosening structure, the safety hazard of the sample flying out can be effectively avoided; all fasteners adopt an embedded design with no protruding sharp structures, making it less likely to scratch during operation. Attached Figure Description

[0026] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0027] Figure 2 is a top view of the present invention;

[0028] Figure 3 is a front view of the present invention;

[0029] Figure 4 is a right view of the present invention;

[0030] Figure 5 is a schematic diagram of the structure of the first clamping component of the present invention;

[0031] Figure 6 is a top view of the first clamping component of the present invention;

[0032] Figure 7 is a front view of the first clamping component of the present invention;

[0033] Figure 8 is a schematic diagram of the structure of the second clamping component of the present invention;

[0034] Figure 9 is a top view of the second clamping component of the present invention;

[0035] Figure 10 is a front view of the second clamping component of the present invention;

[0036] The labels in the diagram are as follows: 1-First clamping component, 2-Second clamping component, 3-M4 hex nut, 4-M4 internal hex head bolt. Detailed Implementation

[0037] For the purpose of further explanation, specific embodiments of the present invention will be described below in conjunction with the accompanying drawings.

[0038] Combination Figure 1 , Figure 2 As shown, the metallographic grinding clamping device for the end face of a small-diameter metal rod of the present invention adopts a split-type mating structure, mainly composed of a first clamping component 1, a second clamping component 2, two M4 hexagonal nuts 3, and two M4 internal hexagonal head bolts 4. The inner wall of the clamping hole has a built-in anti-vibration pad, and the bolts are equipped with spring washers. The two sets of bolt and nut assemblies are symmetrically arranged vertically along the axis of the clamping hole. When the bolts are tightened, the two clamping components are smoothly mated, achieving uniform clamping of the small rod sample inside the central hole.

[0039] Combination Figure 5 , Figure 6 , Figure 7 As shown, on the non-matementing outer end face of the first clamping component 1, two regular hexagonal grooves are symmetrically formed vertically. The groove dimensions are precisely matched with the M4 hexagonal nut 3, allowing the nut to be fully embedded in the groove, achieving circumferential anti-rotation and axial positioning. When tightening the bolt, no additional tools are needed to fix the nut; the operation can be completed on one side. The bottom of each hexagonal groove is machined with a through hole leading to the mating surface for the bolt thread to pass through. A semi-cylindrical groove is machined vertically at the center of the end face, with the groove axis strictly perpendicular to the bottom surface of the component. After the two components are mated, this groove forms half of the central clamping hole.

[0040] Combination Figure 8 , Figure 9 , Figure 10As shown, on the non-materical outer end face of the second clamping component 2, two countersunk through holes are formed at positions corresponding to the nut groove of the first clamping component. The outer side of the through hole is a countersunk step, the depth of which matches the head height of the M4 hexagon socket head cap screw 4. After the bolt is tightened, the head is completely recessed into the hole and does not protrude from the component surface, avoiding operational scratches and equipment interference. The inner side of the through hole is a smooth hole, which is coaxially aligned with the smooth hole of the first clamping component. The center position of its mating end face is also machined with a semi-cylindrical groove, which is coaxially aligned with the groove of the first clamping component, together forming a complete central clamping through hole.

[0041] The specific usage of this embodiment is as follows:

[0042] Sample pretreatment: Cut a bar sample with a length of about 15mm, grind the end face to be ground with silicon carbide sandpaper to remove cutting burrs and surface heat deformation layer, and set aside.

[0043] Pre-assembly of the device: Press the two M4 hexagonal nuts 3 into the hexagonal grooves of the first clamping component 1 respectively, ensuring that they fit the bottom of the groove completely and without looseness; put the spring washer on the M4 internal hexagonal cylindrical head bolt 4, insert it from the countersunk hole side of the second clamping component 2, and pre-tighten the corresponding nut to keep the two clamping components in a slightly open state, with sufficient sample loading gap left in the center clamping hole.

[0044] Sample placement: Insert the pretreated brass rod sample into the central clamping hole from the top of the device, adjust the axial position of the sample so that the end face to be ground protrudes slightly from the bottom surface of the device by about 0.2mm, ensuring that the end face of the sample contacts the abrasive first in the initial stage of grinding, and avoid the bottom surface of the device directly abrading the sandpaper.

[0045] Symmetrical tightening: Use an Allen wrench to alternately and evenly tighten the two bolts to ensure that the sample does not move axially or rotate circumferentially, while avoiding excessive clamping force that could cause indentation deformation on the surface of the bar sample.

[0046] Grinding and polishing operation: Start the metallographic grinding and polishing machine, place the device stably on the grinding and polishing disc, and change sandpaper of different grits in sequence according to the standard sample preparation process to complete the rough grinding and fine grinding. Then change the polishing cloth and use diamond polishing agent to complete the polishing process.

[0047] Disassembly and storage: After polishing, rinse the surface of the device to remove the grinding debris and polishing agent residue. Loosen the bolts in sequence, separate the two clamping parts and take out the sample. After cleaning and drying the device, put it back in its place for future use.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A metallographic grinding clamping device for the end face of a small-diameter metal rod, characterized in that, include: The clamping device component (1) and clamping device component (2) form the core framework of the main body of the device. The clamping mechanism consists of two sets of M4 hexagonal nuts (3) and M4 socket head cap screws (4). Components (1) and (2) are connected by two sets of M4 socket head cap screws (4) and matching M4 hexagonal nuts (3). A hole for placing metallographic samples is provided at the center of the entire device. The clamping device component (1) has two grooves, and the M4 hexagonal nuts (3) can be embedded in the grooves of the clamping device component (1). Both components have through holes for placing the M4 socket head cap screws (4). By tightening the M4 socket head cap screws (4), a controllable preload can be applied to the metal sample. Its function is to clamp the metallographic sample placed in the hole, so that it is firmly fixed and does not produce relative movement.

2. The metallographic grinding clamping device for the end face of a small-diameter metal rod according to claim 1, characterized in that, The clamping device component (1) and the clamping device component (2) are each provided with a semi-circular hole to form a complete cavity to accommodate the dimensional deviation of the columnar metal sample.

3. The metallographic grinding clamping device for the end face of a small-diameter metal rod according to claim 1, characterized in that, The device also includes a shock-absorbing pad, which is disposed at the contact interface between the hole where the metallographic sample is placed and the metal sample, and is used to counteract the vibration generated during the grinding process.

4. The metallographic grinding clamping device for the end face of a small-diameter metal rod according to claim 1, characterized in that, The device also includes a spring washer, which is disposed between the contact surface of the M4 internal hexagonal head bolt (4) and the clamping device component (2) to distribute pressure and prevent loosening.

5. The metallographic grinding clamping device for the end face of a small-diameter metal rod according to claim 3, characterized in that, The shock-absorbing pad is made of an elastic polymer material.

6. The metallographic grinding clamping device for the end face of a small-diameter metal rod according to claim 4, characterized in that, The spring washer is made of stainless steel.

7. The metallographic grinding clamping device for the end face of a small-diameter metal rod according to claim 1, characterized in that, The clamping device component (1) and the clamping device component (2) are made of stainless steel or aluminum alloy.

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