Hydraulic sample punching machine and method for preparing transmission electron microscopic sample

Abstract

The invention discloses a hydraulic sample punching machine and method for preparing a transmission electron microscopic sample. The top cover is arranged above the base, the sliding seat is arranged between the top cover and the base, the top cover and the base are connected through the stand column, the sliding seat is connected to the stand column in an up-down moving mode through the sliding seat guide sleeve, and the hydraulic jack is installed between the top cover and the sliding seat and used for driving the sliding seat to move up and down. The upper male die unit and the lower female die unit are fixedly connected to the sliding base and the base respectively, the upper male die unit and the lower female die unit are connected in a vertically movable mode, a to-be-stamped metal plate is placed on the lower female die unit, and accurate positioning stamping of the to-be-stamped metal plate is achieved through relative movement between the upper male die unit and the lower female die unit. Labor-saving blanking is achieved through the hydraulic jack, the material utilization rate is increased through the positioning pin, the sample yield is increased, manual intervention is reduced by arranging automatic discharging and a reset spring, the production efficiency and operation convenience are improved, and normal operation of equipment is protected.

Description

Technical Field

[0001] The invention belongs to the technical field of sample preparation equipment, and in particular relates to a hydraulic punching machine and a method for preparing transmission electron microscopic samples. Background Art

[0002] In modern industrial production and materials science research, transmission electron microscopy (TEM) plays a vital role and has strict requirements for sample preparation. The sample must be a disc with a standard diameter of 3mm and a thickness between 10um and 100um before thinning, and the edges must be smooth and burr-free. The rationality and advancement of the structure of the sample punching equipment directly affect the quality and precision of the stamping parts, and thus affect the reliability of the experimental results, as well as the efficiency of sample preparation and the safety and convenience of operation.

[0003] Existing transmission electron microscope metal sample punchers are mainly of two types: vertical and horizontal. They shear metal sheets through the shear force generated between the moving pressure head and the fixed punch. However, the existing equipment still has some shortcomings as follows: the transmission mode is mainly manual machinery, which makes it difficult to slice high-strength and high-wear-resistant materials, affecting the sample preparation efficiency; the equipment structure is open pressure transmission, and the mold lacks a guiding mechanism, resulting in low dynamic accuracy, which affects the sample accuracy and surface quality; the sample lacks a positioning mechanism, the punching position distribution is unreasonable, which reduces the material utilization rate and the sample output quantity is small; the sample lacks a reasonable edge pressing mechanism, which leads to wrinkling of the sample and the metal sheet after punching; the equipment operation efficiency is low, and manual unloading, manual sampling, and manual resetting of the equipment are required after the punching is completed. Summary of the invention

[0004] In order to solve the problems existing in the background technology, the purpose of the present invention is to provide a hydraulic punching machine and method for preparing transmission electron microscopy samples, so as to solve the problems of low operating efficiency and poor sample preparation accuracy of the punching machine in the prior art.

[0005] The technical solution adopted by the present invention is: 1. A hydraulic punching machine for preparing transmission electron microscopy samples: It includes a base, a slide, a column, a top cover, a hydraulic jack, an upper punch unit and a lower die unit; the top cover and the base are respectively fixedly connected to the upper and lower ends of the column, the slide is located between the base and the top cover, and the slide is connected to the column movably up and down, the hydraulic jack is installed between the top cover and the slide, the upper punch unit and the lower die unit are respectively fixedly connected to the slide and the base, the metal sheet to be stamped is placed on the lower die unit, and the precise positioning and stamping of the metal sheet to be stamped is achieved through the relative movement between the upper punch unit and the lower die unit.

[0006] The upper punch unit comprises an upper die seat, an annular upper die cushion block, an annular blank holder ring limiting plate, a blank holder ring, a blank holder spring, a blank holder ring insert, a punch, a ball guide sleeve, a punch cushion block and a punch fixing sleeve; The upper surface of the upper die seat is fixedly connected to the lower surface of the slide seat, the upper surface of the upper die pad is fixedly connected to the lower surface of the upper die seat, the upper surface of the pressure ring limiting plate is fixedly connected to the lower surface of the upper die pad, the pressure ring is installed in the middle of the pressure ring limiting plate, the pressure ring insert is fixedly installed on the inner circumference of the pressure ring, the upper die seat, the pressure ring limiting plate, and the pressure ring insert are all provided with a first through hole in the middle, the punch pad is arranged at the first through hole of the upper die seat, and the top of the punch pad is fixedly connected to the lower surface of the slide seat, the upper and lower parts of the punch fixing sleeve are fixedly connected to the lower surface of the slide seat, and the upper and lower parts of the punch fixing sleeve are fixedly connected to the lower surface of the slide seat. The first through holes are respectively arranged on the upper die seat and the pressure ring limit plate, the punch is fixedly installed on the inner periphery of the punch fixing sleeve, the top of the punch is fixedly connected to the lower surface of the punch pad, the ball guide sleeve is fixedly installed at the position of the first through hole of the pressure ring insert, the lower part of the punch passes through the first through hole in the middle of the pressure ring limit plate and is arranged in the middle of the ball guide sleeve, a pressure spring is arranged on the outer periphery of the middle part of the punch, and the upper and lower ends of the pressure spring are respectively connected to the lower surface of the upper die seat and the top of the pressure ring, and the pressure spring is used for resetting the pressure ring.

[0007] The lower die unit comprises a lower die seat, an annular die fixing plate, a die, an ejector spring, an ejector, a locating pin and a locating pin spring; the lower surface of the lower die seat is fixedly connected to the upper surface of the base, the lower surface of the die fixing plate is fixedly connected to the upper surface of the lower die seat, the die is installed in the middle of the die fixing plate, a second through hole is provided in the middle of the die, the ejector can be movably arranged at the position of the second through hole in the middle of the die, the bottom end of the ejector is connected to the lower die seat through the ejector spring, a blind hole is provided at the top of the die, a locating pin spring and a locating pin are provided in the blind hole at the top of the die, the upper and lower ends of the locating pin spring are respectively connected to the bottom of the locating pin and the inner bottom surface of the blind hole of the die.

[0008] The hydraulic punching machine also includes a support spring, a limit sleeve and a limit sleeve gasket; the support spring is wound around the outer periphery of the two columns in the hydraulic punching machine, and the upper and lower ends of the support spring are respectively connected to the lower end surface of the slide and the upper end surface of the base, and the support spring is used to realize the resetting of the slide; the limit sleeve is arranged on the outer periphery of the other two columns, the lower end surface of the limit sleeve is connected to the upper end surface of the base, and the limit sleeve gasket is installed on the upper end surface of the limit sleeve, and the limit sleeve is used to limit the bottom dead point position of the slide.

[0009] The lower end surface of the inner side of the pressure ring limiting plate is stepped, and the upper end surface of the outer side of the pressure ring is stepped. The stepped lower end surface of the pressure ring limiting plate matches the stepped upper end surface of the pressure ring, so that the pressure ring can be installed on the inner side of the pressure ring limiting plate so as to move up and down. At the same time, the pressure ring limiting plate limits the moving stroke of the pressure ring.

[0010] The punch in the upper punch unit and the ejector in the lower die unit are coaxially arranged, and the metal sheet to be stamped is placed between the punch and the ejector. The punch, the positioning pin and the ejector are used to achieve precise positioning and stamping of the metal sheet to be stamped.

[0011] The upper die seat in the upper punch unit is connected with a die guide sleeve, and the lower die seat in the lower concave die unit is connected with a die guide column. The die guide sleeve can be installed on the upper part of the die guide column so as to move up and down along the die guide column.

[0012] The bottom end of the hydraulic jack is fixedly connected to the slide seat, the top end of the piston rod of the hydraulic jack is in contact with the lower surface of the top cover, and the hydraulic jack is used to drive the slide seat to move up and down.

[0013] The lower end face of the blank holder is flush with the lower end face of the blank holder insert and is lower than the lower end face of the punch, and the lower end face of the punch is lower than the lower end face of the blank holder limit plate; the upper end face of the die is flush with the upper end face of the ejector, and the upper end face of the locating pin is higher than the upper end face of the ejector.

[0014] 2. A method for preparing a transmission electron microscopy sample, comprising the following steps: Step S1, placing the metal sheet to be punched horizontally on the upper end surface of the die in the lower die unit, and moving the metal sheet to be punched so that the edge of the metal sheet is tangent to the outer diameter of the positioning pin in the lower die unit; Step S2, control the piston rod of the hydraulic jack to move upward to push the slide to move downward, the lower end surface of the blank holder ring block first contacts the metal sheet to be punched and applies a blank holder force, then the slide continues to move downward, the punch contacts the metal sheet and cooperates with the die to generate a shear force to punch out a sample, and at the same time, the remaining part of the metal sheet is stuck at the lower end of the punch, the punch pushes the sample into the inside of the die, the sample pushes the ejector pin to move downward, the ejector pin spring is compressed, and the punching is completed; Step S3, the piston rod of the hydraulic jack moves downward, and the supporting spring pushes the slide seat to move upward, thereby pushing out the remaining part of the metal sheet stuck on the punch, completing automatic unloading.

[0015] The die cutting edge of the present invention adopts a rounded structure, and the spring at the lower end of the ejector pin is always in a compressed state, thereby eliminating the tensile stress in the area to be cut of the metal sheet blanking part, making it in a three-dimensional compressive stress state and being blanked in the form of pure shear, so that the sample has a smooth edge and no burrs, and under the extrusion of the punch and the ejector pin, the sample surface is flat and smooth. It is guaranteed that in subsequent experiments, the thin area of ​​the sample is prepared by the electrolytic double spraying method, the electrolyte uniformly corrodes the center of the sample and forms holes, and then the microscopic characteristics of the thin area around the hole are observed under a transmission electron microscope. Samples with burrs or uneven surfaces are prone to form multiple small holes or eccentric holes after electrolytic double spraying, so that the thin area of ​​the sample cannot be obtained, and then it cannot be observed under a transmission electron microscope, resulting in sample waste and experimental failure.

[0016] The present invention utilizes a combination of a limit sleeve and a limit washer to set an upper mold pad, and the limit washer and the upper mold pad are made of polyurethane rubber, thereby providing a flexible limit buffer. In addition, when the slide moves to the bottom dead center position, a spray mark is sprayed at the intersection of the upper end surface of the slide and the column as a warning prompt, thereby preventing excessive downward movement due to manual operation errors, causing the upper and lower molds to collide rigidly, affecting the service life of the equipment.

[0017] The present invention limits the position of the metal sheet to be punched by reasonably arranging the locating pins, so that when punching multiple samples, the positions selected on the metal sheet are evenly distributed and appropriately spaced, thereby preparing more samples and improving material utilization. The locating pins are combined with locating pin springs to avoid rigid interference with the equipment.

[0018] The present invention adopts a closed structure and is designed with a precise guiding mechanism. The column and guide sleeve cooperate to guide the movement of the slide, and the mold guide column and mold guide sleeve accurately guide the punch for precise blanking. The blank holder ring and the blank holder spring are reasonably equipped so that the blank holder ring contacts the metal sheet to be punched before the punch, thereby providing a suitable blank holder force. The blank holder ring insert has a gear ring and cooperates with the blank holder spring to limit the vertical flow of the material, further ensuring the blank holder effect and preventing the metal sheet from wrinkling during blanking. Otherwise, once the metal sheet wrinkles, the subsequent sample will have additional large plastic deformation. When observing the dislocation configuration inside the sample under a transmission electron microscope, it is difficult to distinguish the intrinsic dislocation of the sample from the interference dislocation introduced by wrinkling, which affects the reliability of the experimental results.

[0019] The beneficial effects of the present invention are: 1. The present invention adopts hydraulic punching technology, designs the structure through strength verification, and selects a small jack to reduce the size of the equipment. Compared with traditional manual punching, it can punch high-strength and wear-resistant materials more labor-savingly, thereby improving the punching efficiency and safety.

[0020] 2. The present invention limits the position of the metal sheet to be punched by reasonably setting the positioning pins, so that when punching multiple samples, the positions selected on the metal sheet are evenly distributed and the spacing is appropriate, so as to prepare more samples and improve material utilization. The positioning pin is combined with the positioning pin spring to avoid rigid interference with the equipment.

[0021] 3. The punch of the present invention adopts a punch fixing sleeve, which is easy to replace. The ball guide sleeve is used to guide the precise movement of the blank holder ring, reducing the direct friction between the inner hole of the blank holder ring and the punch, thereby ensuring the rigidity of the punch and increasing the service life of the punch. The gear ring structure and inner hole structure of the blank holder ring are easy to wear, and inserts are used for easy replacement. The die cutting edge is easy to wear, and is designed separately from the die fixing plate for easy replacement.

[0022] 4. After the punching is completed, the blank holder structure of the present invention can automatically unload the metal sheet, and the ejector structure can automatically eject the sample, thereby reducing manual operation and improving production efficiency and convenience of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below.

[0024] Figure 1 It is a three-dimensional diagram of the hydraulic punching machine after being reset in the present invention; Figure 2 It is a right side view of the hydraulic punching machine after being reset in the present invention; Figure 3 It is a cross-sectional view of the hydraulic punching machine after being reset in the present invention; Figure 4 It is a right side view of the hydraulic punching machine after punching in the present invention; Figure 5 It is a cross-sectional view after the hydraulic punching machine of the present invention has completed punching; Figure 6 It is a first cross-sectional view of the hydraulic punching machine after being reset in the present invention; Figure 7 It is a second cross-sectional view of the hydraulic punching machine after being reset in the present invention; Figure 8 It is the third cross-sectional view of the hydraulic punching machine after being reset in the present invention.

[0025] In the figure: base-1; limit sleeve-2; limit sleeve gasket-3; slide-4; column-5; top cover-6; hydraulic jack-7; support spring-8; upper die seat-9; upper die pad-10; blank holder limit plate-11; blank holder-12; blank holder spring-13; blank holder insert-14; punch-15; ball guide sleeve-16; lower die seat-17; die fixing plate-18; die-19; ejector spring-20; ejector-21; locating pin-22; mold guide column-23; mold guide sleeve-24; spring pad-25; locating pin spring-26; punch pad-27; punch fixing sleeve-28; slide guide sleeve-29. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] like Figure 1As shown, the hydraulic punching machine includes a base 1, a slide 4, a column 5, a top cover 6, a hydraulic jack 7, an upper punch unit and a lower die unit; the top cover 6 and the base 1 are respectively fixedly connected to the upper and lower ends of the column 5, the slide 4 is located between the base 1 and the top cover 6, and the slide 4 is connected to the column 5 movably up and down, the hydraulic jack 7 is installed between the top cover 6 and the slide 4, the upper punch unit and the lower die unit are respectively fixedly connected to the slide 4 and the base 1, the metal sheet to be stamped is placed on the lower die unit, and the precise positioning and stamping of the metal sheet to be stamped is achieved through the relative movement between the upper punch unit and the lower die unit.

[0028] like Figure 2 As shown, the base 1, the slide 4, and the top cover 6 are arranged in parallel and spaced apart. The bottom end of the column 5 is fixedly connected to the countersunk hole opened on the periphery of the base 1, and the periphery of the top cover 6 is provided with a light hole, the aperture of the light hole of the top cover 6 is smaller than the diameter of the smooth surface of the column 5, and larger than the diameter of the threaded surface of the column 5, and the top cover 6 is fixedly connected to the top of the column 5 at the position of the light hole through a nut, as shown in FIG. Figure 6 As shown, the slide 4 moves up and down along the column 5 through the slide guide sleeve 29, thereby ensuring the accuracy of the up and down movement of the slide 4 and improving the surface quality of the sample. The lower end of the hydraulic jack 7 is fixed to the upper end of the slide 4 by a hexagon socket bolt, and the upper end of the piston rod of the hydraulic jack 7 contacts the lower surface of the top cover 6. The up and down movement of the piston rod of the hydraulic jack 7 drives the slide 4 to move up and down, thereby providing a larger blanking force, and the force can be manually added one by one, making the blanking more stable, so that high-strength wear-resistant materials can be blanked more easily and efficiently.

[0029] like Figure 4 As shown, the support spring 8 is in a compressed state throughout the whole process and is diagonally distributed. It is sleeved on the two diagonally distributed columns 5. Only two support springs 8 are used to provide appropriate supporting force and reduce the punching force. It is also convenient for the equipment to be reset after the punching is completed. The lower end of the support spring 8 is connected to the upper end face of the base 1, and the upper end of the support spring 8 is connected to the lower end face of the slide 4. The support spring 8 moves up and down with the slide 4. After the punching is completed, the pressure reducing valve of the hydraulic jack 7 is opened, and the slide 4 is automatically reset under the thrust of the support spring 8, thereby improving the punching efficiency.

[0030] like Figure 3 As shown, the upper punch unit includes an upper die seat 9, an annular upper die cushion block 10, an annular blank holder ring limiting plate 11, a blank holder ring 12, a blank holder spring 13, a blank holder ring insert 14, a punch 15, a ball guide sleeve 16, a punch cushion block 27 and a punch fixing sleeve 28; The upper surface of the upper die seat 9 is fixedly connected to the lower surface of the slide 4, the upper die pad 10 is located between the upper die seat 9 and the pressure ring limiting plate 11, the upper surface of the upper die pad 10 is fixedly connected to the lower surface of the upper die seat 9, the upper surface of the pressure ring limiting plate 11 is fixedly connected to the lower surface of the upper die pad 10, the pressure ring 12 is movably installed in the middle of the pressure ring limiting plate 11, the pressure ring insert 14 is fixedly installed on the inner periphery of the pressure ring 12, the ball guide sleeve 16 is installed in the middle of the pressure ring insert 14, the punch fixing sleeve 28, the pressure ring 12, the upper die seat 9, the pressure ring limiting plate 11, and the pressure ring insert 14 are all provided with a first through hole in the middle, the punch pad 27 is arranged at the first through hole of the upper die seat 9, and the top of the punch pad 27 is fixedly connected to the lower surface of the slide 4, the upper and lower parts of the punch fixing sleeve 28 The first through holes are respectively arranged on the upper die seat 9 and the pressure ring limit plate 11, the punch 15 is fixedly installed on the inner periphery of the punch fixing sleeve 28, the top of the punch 15 is fixedly connected to the lower surface of the punch pad 27, the ball guide sleeve 16 is fixedly installed at the position of the first through hole of the pressure ring insert 14, the lower part of the punch 15 passes through the first through hole in the middle of the pressure ring limit plate 11 and can be movably arranged in the middle of the ball guide sleeve 16 up and down, the outer periphery of the middle part of the punch 15 is provided with a pressure spring 13, the pressure spring 13 is located at the first through hole in the middle of the pressure ring limit plate 11, and the upper and lower ends of the pressure spring 13 are respectively connected to the lower surface of the upper die seat 9 and the top of the pressure ring 12, the pressure spring 13 is used to provide pressure force and reset the pressure ring 12, and a gear ring is provided at the lower part of the pressure ring insert 14 to increase the pressure force.

[0031] The upper die seat 9 is fixed to the lower end surface of the slide seat 4 by means of hexagon socket bolts, the pressure ring limiting plate 11 is fixed to the lower end surface of the upper die pad 10 by means of hexagon socket bolts, and the upper die pad 10 is fixed to the lower end surface of the upper die seat 9 . The punch 15 is arranged in the first through hole in the middle of the upper die seat 9, and the punch pad 27 is installed on the top of the punch 15, and together with the punch fixing sleeve 28, the up and down movement of the punch 15 is limited; the outer diameter of the upper end of the pressure ring 12 is slightly smaller than the inner hole diameter of the pressure ring limiting plate 11, so that the pressure ring 12 can move up and down smoothly, the lower end of the pressure spring 13 contacts the bottom surface of the blind hole at the upper end of the pressure ring 12, and the upper end of the pressure spring 13 contacts the upper die seat 9. The pressure spring 13 is always in a compressed state, which is convenient for pressure and unloading. In the initial state, the pressure ring 12 is flush with the lower end surface of the pressure ring insert 14 and is lower than the lower end surface of the punch 15, and the lower end surface of the punch 15 is lower than the lower end surface of the pressure ring limiting plate 11, thereby smoothly ensuring that the pressure ring 12 first contacts the metal sheet to be stamped and applies the pressure force, and then the punch 15 contacts the metal sheet to be stamped, thereby ensuring that the edges of the sample and the metal sheet to be stamped are not wrinkled.

[0032] The outer diameter of the lower end of the blank holder insert 14 is interference fit with the inner diameter of the first through hole of the blank holder 12. The blank holder insert 14 is tangent to the outer diameter of the punch 15 through the ball guide sleeve 16, thereby preventing the blank holder insert 14 from directly colliding with the punch 15 in the radial direction, and cooperates with the punch fixing sleeve 28 to improve the rigidity and service life of the punch 15. To ensure the service life of the punch 15, the punch fixing sleeve 28 with a stepped top design can limit the blank holder 12 from moving upward to limit the movement stroke of the blank holder 12.

[0033] like Figure 5 As shown, the lower die unit includes a lower die base 17, an annular die fixing plate 18, a die 19, an ejector spring 20, an ejector 21, a locating pin 22 and a locating pin spring 26; the lower surface of the lower die base 17 is fixedly connected to the upper surface of the base 1, the lower surface of the die fixing plate 18 is fixedly connected to the upper surface of the lower die base 17, the die 19 is installed in the middle of the die fixing plate 18, the middle of the die 19 is provided with a second through hole, the ejector 21 is movably arranged at the position of the second through hole in the middle of the die 19, the bottom end of the ejector 21 is connected to the lower die base 17 through the ejector spring 20, the top of the die 19 is provided with a blind hole, the blind hole at the top of the die 19 is provided with a locating pin spring 26 and a locating pin 22, the upper and lower ends of the locating pin spring 26 are respectively connected to the bottom of the locating pin 22 and the inner bottom surface of the blind hole of the die 19.

[0034] The lower die seat 17 is fixed to the upper end surface of the base 1 by means of hexagon socket bolts, and the die 19 is fixed to the upper end surface of the base 1 by means of countersunk holes on the die fixing plate 18. The outer diameter of the upper end of the ejector pin 21 is slightly smaller than the second through hole of the die 19, so that the ejector pin 21 can move up and down easily. The top end of the ejector pin spring 20 is connected to the ejector pin 21, and the bottom end of the ejector pin spring 20 is connected to the upper surface of the lower die seat 17 through the spring pad 25. The ejector pin spring 20 is always in a compressed state, and the upper end of the ejector pin spring 20 contacts the lower end surface of the ejector pin 21, and the lower end of the ejector pin spring 20 contacts the spring pad 25, so as to eject the sample stuck in the inner diameter of the punch 15, so as to facilitate subsequent sampling.

[0035] The lower end of the locating pin 22 contacts the bottom of the blind hole at the upper end of the die 19 through the locating pin spring 26, avoiding the rigid collision between the locating pin 22 and the pressure ring 12, making it convenient for the edge of the metal sheet to be punched to be tangent to the locating pin 22 during punching, thereby ensuring a reasonable and accurate punching position, improving material utilization, and increasing the number of samples; the lower die seat 17 fixes the die guide column 23 through the countersink, and the upper die seat 9 fixes the die guide sleeve 24, and the die guide column 23 and the die guide sleeve 24 can move relative to each other. The upper die seat 9 moves up and down along the die guide column 23 through the die guide sleeve 24, combined with the directional movement of the slide guide sleeve 29 and the column 5, to ensure the punching accuracy and the sample has no flash and burrs.

[0036] like Figure 7As shown, the base 1 is provided with a threaded hole and connected to the countersunk hole of the lower die seat 17 by a hexagon socket bolt. The top cover 6 is provided with a light hole to ensure that the column 5 passes smoothly and is fixed by a nut. The slide 4 is provided with a threaded hole and connected to the countersunk hole of the pressure ring limit plate 11 by a hexagon socket bolt, and the slide 4 is provided with a countersunk hole and connected to the threaded hole of the upper die seat 9 by a hexagon socket bolt. The hydraulic jack 7 is connected to the threaded hole of the slide 4 by a hexagon socket bolt, thereby fixing the position of the hydraulic jack 7 and ensuring stable and accurate pressure output. The slide 4 is provided with a countersunk hole, and the slide 4 is connected and fixed to the threaded hole of the upper die seat 9 by a hexagon socket bolt. The lower die seat 17 is provided with a threaded hole and connected to the countersunk hole of the die fixing plate 18 by a hexagon socket bolt, thereby fixing the die 19. The upper end surface of the ejector 21 and the upper end surface of the die 19 are flush with the upper end surface of the die fixing plate 18 to ensure that the metal sheet to be stamped is placed horizontally.

[0037] The hydraulic punching machine also includes a support spring 8, a limit sleeve 2 and a limit sleeve gasket 3; the support spring 8 is wound around the outer periphery of the two columns 5 in the hydraulic punching machine, and the upper and lower ends of the support spring 8 are respectively connected to the lower end surface of the slide 4 and the upper end surface of the base 1, and the support spring 8 is used to realize the reset of the slide 4; the limit sleeve 2 is arranged on the outer periphery of the other two columns 5, the inner diameter of the limit sleeve 2 is slightly larger than the outer diameter of the column 5, the height of the limit sleeve 2 is less than the height of the column 5, the lower end surface of the limit sleeve 2 is connected to the upper end surface of the base 1, and the limit sleeve gasket 3 is installed on the upper end surface of the limit sleeve 2, and the limit sleeve 2 is used to limit the bottom dead point position of the slide 4.

[0038] The inner diameters of the limit sleeve 2 and the limit sleeve gasket 3 are equal and slightly larger than the column 5. The limit sleeve 2 is diagonally distributed on the two columns 5, and the outer diameter of the limit sleeve gasket 3 is larger than the limit sleeve 2. When the slide 4 moves further downward, the upper end surface of the limit sleeve gasket 3 contacts the lower end surface of the slide 4, and prevents the slide 4 from moving further under the support of the limit sleeve 2. The upper mold pad 10 and the limit sleeve gasket 3 are both made of polyurethane rubber material. When the slide 4 moves to the bottom dead center, it provides flexible buffering to prevent the upper and lower molds from rigidly colliding. At the intersection of the upper end surface of the slide and the column, the spray mark is exposed, thereby preventing excessive downward movement due to manual operation errors, causing the upper and lower molds to rigidly collide, affecting the service life of the equipment.

[0039] The lower end surface of the inner side of the blank holding ring limiting plate 11 is stepped, and the upper end surface of the outer side of the blank holding ring 12 is stepped. The stepped lower end surface of the blank holding ring limiting plate 11 and the stepped upper end surface of the blank holding ring 12 match, so that the blank holding ring 12 can be installed on the inner side of the blank holding ring limiting plate 11 so as to move up and down. At the same time, the blank holding ring limiting plate 11 limits the moving stroke of the blank holding ring 12.

[0040] The punch 15 in the upper punch unit and the ejector pin 21 in the lower die unit are coaxially arranged, and the metal sheet to be stamped is placed between the punch 15 and the ejector pin 21. The punch 15, the die 19, the positioning pin 22 and the ejector pin 21 are used to achieve precise positioning and stamping of the metal sheet to be stamped.

[0041] like Figure 8 As shown, the upper die base 9 in the upper punch unit is connected to a die guide sleeve 24, and the lower die base 17 in the lower die unit is connected to a die guide column 23. The die guide sleeve 24 can be installed on the upper part of the die guide column 23 so as to move up and down along the die guide column 23.

[0042] The bottom end of the hydraulic jack 7 is fixedly connected to the slide 4, and the top end of the piston rod of the hydraulic jack 7 is in contact with the lower surface of the top cover 6. The hydraulic jack 7 is used to drive the slide 4 to move up and down.

[0043] In the initial state, the lower end face of the blank holder 12 is flush with the lower end face of the blank holder insert 14 and is lower than the lower end face of the punch 15, and the lower end face of the punch 15 is lower than the lower end face of the blank holder limit plate 11; in the initial state, the upper end face of the die 19 is flush with the upper end face of the ejector pin 21, and the upper end face of the locating pin 22 is higher than the upper end face of the ejector pin 21.

[0044] An embodiment of the present invention comprises the following steps: Step S1: During the stroke, the metal sheet to be stamped is horizontally placed on the upper end surface of the die 19 in the lower die unit, and the metal sheet to be stamped is positioned using the positioning pins 22: When the metal sheet is used for the first time, the metal sheet to be punched is moved so that the edge of the metal sheet is tangent to the outer diameter of the positioning pin 22 in the lower die unit; After the holes of the sample are punched out on the metal sheet, the positioning pins 22 can be set at the holes on the metal sheet to position the metal sheet; Step S2, operate the handle of the hydraulic jack 7, control the piston rod of the hydraulic jack 7 to move upward to push the slide 4 to move downward, thereby driving the upper die seat 9, the upper die cushion block 10, the blank holder ring limit plate 11, the blank holder ring 12, the blank holder spring 13, the blank holder ring insert 14, the punch 15, the ball guide sleeve 16, the punch cushion block 27 and the punch fixing sleeve 28 in the upper punch unit to move downward as a whole, and continue to move. The lower end surface of the blank holder ring insert 14 in the upper punch unit first contacts the metal sheet to be stamped and applies the blank holder force, and then the slide 4 Continue to move downward, the blank holder 12, the blank holder insert 14, and the ball guide sleeve 16 are stationary, the blank holder spring 13 is further compressed, the blank holder force increases, and the movement continues. The punch 15 in the upper punch unit contacts the metal sheet and cooperates with the die 19 to generate a shear force to punch out a sample. At the same time, the remaining part of the metal sheet (i.e., the non-sample part of the metal sheet) is stuck at the lower end of the punch 15. The punch 15 pushes the sample into the inside of the die 19. The sample pushes the ejector 21 in the lower die unit to move downward, and the ejector spring 20 is compressed to complete the punching. Step S3, during the return stroke, open the pressure reducing valve of the hydraulic jack 7, the piston rod of the hydraulic jack 7 moves downward, the support spring 8 pushes the slide 4 upward, thereby driving the upper punch unit to move upward as a whole, the edge clamp spring 13 gradually increases, the edge clamp ring 12, the edge clamp ring block 14 and the ball guide sleeve 16 remain fixed, thereby pushing out the remaining non-sample metal sheet stuck on the punch 15, and completing the automatic unloading. Continue to move, the edge clamp ring limit plate 11 continues to move upward with the whole, when the inner diameter countersunk surface of the edge clamp ring limit plate 11 contacts the lower end of the outer diameter of the edge clamp ring 12, the edge clamp ring 12 and the edge clamp ring block 14 are lifted, and the ejector spring 20 is extended, pushing the ejector 21 upward to automatically eject the sample, and the equipment is automatically reset under the push of the support spring 8.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hydraulic punching machine for preparing transmission electron microscopy samples, characterized in that: The invention comprises a base (1), a slide (4), a column (5), a top cover (6), a hydraulic jack (7), an upper punch unit and a lower die unit; the top cover (6) and the base (1) are respectively fixedly connected to the upper and lower ends of the column (5); the slide (4) is located between the base (1) and the top cover (6), and the slide (4) is connected to the column (5) so as to be movable up and down; the hydraulic jack (7) is installed between the top cover (6) and the slide (4); the upper punch unit and the lower die unit are respectively fixedly connected to the slide (4) and the base (1); a metal sheet to be stamped is placed on the lower die unit; and accurate positioning and stamping of the metal sheet to be stamped is achieved through relative movement between the upper punch unit and the lower die unit.

2. A hydraulic punching machine for preparing transmission electron microscopy samples according to claim 1, characterized in that: The upper punch unit comprises an upper die seat (9), an annular upper die cushion block (10), an annular blank holder ring limiting plate (11), a blank holder ring (12), a blank holder spring (13), a blank holder ring insert (14), a punch (15), a ball guide sleeve (16), a punch cushion block (27) and a punch fixing sleeve (28); The upper surface of the upper die seat (9) is fixedly connected to the lower surface of the slide seat (4), the upper surface of the upper die pad (10) is fixedly connected to the lower surface of the upper die seat (9), the upper surface of the pressure ring limiting plate (11) is fixedly connected to the lower surface of the upper die pad (10), the pressure ring (12) is installed in the middle of the pressure ring limiting plate (11), the pressure ring insert (14) is fixedly installed on the inner periphery of the pressure ring (12), the upper die seat (9), the pressure ring limiting plate (11), and the pressure ring insert (14) are all provided with a first through hole in the middle, the punch pad (27) is arranged at the first through hole of the upper die seat (9), and the top of the punch pad (27) is fixedly connected to the lower surface of the slide seat (4), the upper and lower parts of the punch fixing sleeve (28) are respectively A first through hole is arranged on the upper die seat (9) and the pressure ring limiting plate (11), the punch (15) is fixedly mounted on the inner periphery of the punch fixing sleeve (28), the top of the punch (15) is fixedly connected to the lower surface of the punch pad (27), the ball guide sleeve (16) is fixedly mounted at the first through hole position of the pressure ring insert (14), the lower part of the punch (15) passes through the first through hole in the middle of the pressure ring limiting plate (11) and is arranged in the middle of the ball guide sleeve (16), the outer periphery of the middle of the punch (15) is provided with a pressure spring (13), and the upper and lower ends of the pressure spring (13) are respectively connected to the lower surface of the upper die seat (9) and the top of the pressure ring (12), and the pressure spring (13) is used for resetting the pressure ring (12).

3. A hydraulic punching machine for preparing transmission electron microscopy samples according to claim 2, characterized in that: The lower die unit comprises a lower die seat (17), an annular die fixing plate (18), a die (19), an ejector spring (20), an ejector (21), a positioning pin (22) and a positioning pin spring (26); the lower surface of the lower die seat (17) is fixedly connected to the upper surface of the base (1), the lower surface of the die fixing plate (18) is fixedly connected to the upper surface of the lower die seat (17), the die (19) is mounted in the middle of the die fixing plate (18), and the middle of the die (19) is fixedly connected to the upper surface of the base (1). A second through hole is provided, and an ejector pin (21) is movably arranged at the position of the second through hole in the middle of the die (19). The bottom end of the ejector pin (21) is connected to the lower die seat (17) via an ejector pin spring (20). A blind hole is provided at the top of the die (19). A positioning pin spring (26) and a positioning pin (22) are provided in the blind hole at the top of the die (19). The upper and lower ends of the positioning pin spring (26) are respectively connected to the bottom of the positioning pin (22) and the inner bottom surface of the blind hole of the die (19).

4. A hydraulic punching machine for preparing transmission electron microscopy samples according to claim 2, characterized in that: The hydraulic punching machine further comprises a support spring (8), a limit sleeve (2) and a limit sleeve gasket (3); the support spring (8) is wound around the outer periphery of two columns (5) in the hydraulic punching machine, the upper and lower ends of the support spring (8) are respectively connected to the lower end surface of the slide seat (4) and the upper end surface of the base (1), and the support spring (8) is used to realize the reset of the slide seat (4); the limit sleeve (2) is sleeved on the outer periphery of the other two columns (5), the lower end surface of the limit sleeve (2) is connected to the upper end surface of the base (1), the limit sleeve gasket (3) is installed on the upper end surface of the limit sleeve (2), and the limit sleeve (2) is used to limit the bottom dead point position of the slide seat (4).

5. A hydraulic punching machine for preparing transmission electron microscopy samples according to claim 2, characterized in that: The lower end surface of the inner side of the blank holding ring limiting plate (11) is stepped, and the upper end surface of the outer side of the blank holding ring (12) is stepped. The stepped lower end surface of the blank holding ring limiting plate (11) matches the stepped upper end surface of the blank holding ring (12), so that the blank holding ring (12) can be installed on the inner side of the blank holding ring limiting plate (11) so as to move up and down. At the same time, the blank holding ring limiting plate (11) limits the movement stroke of the blank holding ring (12).

6. A hydraulic punching machine for preparing transmission electron microscopy samples according to claim 3, characterized in that: The punch (15) in the upper punch unit and the ejector pin (21) in the lower die unit are coaxially arranged, and the metal sheet to be stamped is placed between the punch (15) and the ejector pin (21). The punch (15), the positioning pin (22) and the ejector pin (21) are used to achieve accurate positioning and stamping of the metal sheet to be stamped.

7. A hydraulic punching machine for preparing transmission electron microscopy samples according to claim 3, characterized in that: The upper die seat (9) in the upper punch unit is connected to a die guide sleeve (24), the lower die seat (17) in the lower die unit is connected to a die guide post (23), and the die guide sleeve (24) is mounted on the upper part of the die guide post (23) so as to be movable up and down along the die guide post (23).

8. The hydraulic punching machine for preparing transmission electron microscopy samples according to claim 2, characterized in that: The bottom end of the hydraulic jack (7) is fixedly connected to the slide seat (4), the top end of the piston rod of the hydraulic jack (7) is in contact with the lower surface of the top cover (6), and the hydraulic jack (7) is used to drive the slide seat (4) to move up and down.

9. A hydraulic punching machine for preparing transmission electron microscopy samples according to claim 2, characterized in that: The lower end surface of the blank holder (12) is flush with the lower end surface of the blank holder insert (14) and is lower than the lower end surface of the punch (15), and the lower end surface of the punch (15) is lower than the lower end surface of the blank holder limiting plate (11); the upper end surface of the die (19) is flush with the upper end surface of the ejector pin (21), and the upper end surface of the positioning pin (22) is higher than the upper end surface of the ejector pin (21).

10. A method for preparing transmission electron microscopic samples applied to the hydraulic punching machine according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step S1, placing the metal sheet to be punched horizontally on the upper end surface of the die (19) in the lower die unit, and moving the metal sheet to be punched so that the edge of the metal sheet is tangent to the outer diameter of the positioning pin (22) in the lower die unit; Step S2, control the piston rod of the hydraulic jack (7) to move upward to push the slide (4) to move downward, the lower end surface of the blank holder ring insert (14) first contacts the metal sheet to be punched and applies a blank holder force, then the slide (4) continues to move downward, the punch (15) contacts the metal sheet and cooperates with the die (19) to generate a shear force to punch out a sample, and at the same time, the remaining part of the metal sheet is stuck at the lower end of the punch (15), the punch (15) pushes the sample into the inside of the die (19), the sample pushes the ejector pin (21) to move downward, the ejector pin spring (20) is compressed, and the punching is completed; Step S3: The piston rod of the hydraulic jack (7) moves downward, and the support spring (8) pushes the slide seat (4) to move upward, thereby pushing out the remaining part of the metal sheet stuck on the punch (15), completing the automatic unloading.

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