Preparation method of micro mold and micro mold

Abstract

The invention provides a preparation method of a micro-mold and the micro-mold, and relates to the technical field of micro-molds, the preparation method of the micro-mold comprises the following steps: preparing a nano block with a required grain size; a template piece is cut on the nanometer block body; grinding the thickness of the template piece to a preset thickness; a mold hole is cut in the template piece; and sequentially stacking and fixing the at least two template pieces to form the micro mold, and enabling the at least two mold holes to be communicated with each other to form a mold cavity. According to the preparation method of the micro-mold, the preparation difficulty of the micro-mold can be reduced, the micro-mold is not prone to deformation in the preparation process, the preparation precision of the micro-mold can be improved, the grain size of the micro-mold is easy to control, the structural strength and toughness of the micro-mold are enhanced, and the service life of the micro-mold is prolonged.

Description

Technical Field

[0001] The present application belongs to the field of micro mold technology, and more specifically, relates to a micro mold preparation method and a micro mold. Background Art

[0002] A micro mold is a mold with sub-millimeter or micron-level micro-feature structures on at least two dimensions. It is widely used in many fields such as microelectronics, micromechanics, biomedicine, optics, and chemical engineering. It can achieve high-precision processing and manufacturing, and provides important support for the development of micro-nano technology.

[0003] In the design and manufacturing process of micro molds, precision and stability are crucial factors. The preparation of micro molds not only requires the mold itself to have extremely high dimensional accuracy and surface quality, but also needs to consider issues such as the selection of its materials, the optimization of the preparation method, and the durability of the mold.

[0004] At present, when processing micro molds with traditional cutting technology, the traditional cutting preparation method will generate large processing stress and heat during the processing, which is easy to cause the shape of the micro mold to change and affect the dimensional accuracy of the micro mold. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a method for preparing a micro mold and a micro mold, so as to solve the problem in the prior art that the traditional cutting process is difficult to ensure the dimensional accuracy of the micro mold.

[0006] To achieve the above objectives, in a first aspect, the present application provides a method for preparing a micro mold, comprising:

[0007] preparing nano-bulks with desired grain sizes;

[0008] cutting a template piece on the nano block;

[0009] Grinding the thickness of at least two of the template members to respective corresponding preset thicknesses;

[0010] Cutting a mold hole on the template;

[0011] At least two of the template members are stacked in sequence, and the mold holes on all the template members are interconnected to form a mold cavity;

[0012] Each two adjacent template members are fixedly connected to form the micro-mold.

[0013] In some embodiments of the first aspect, grinding the thickness of the template members to respective corresponding preset thicknesses comprises:

[0014] Fixing the template member to a grinding jig;

[0015] The template material is ground multiple times in sequence using a plurality of grinding pieces with increasing mesh sizes until the thickness of the template reaches the corresponding preset thickness.

[0016] In some embodiments of the first aspect, the template member is fixed to the grinding jig using an adhesive.

[0017] In some embodiments of the first aspect, the mold hole is cut on the template member using a femtosecond laser.

[0018] In some embodiments of the first aspect, the preset thickness is no greater than 50 μm.

[0019] In some embodiments of the first aspect, the thickness of the template member before grinding is 5 to 20 times the preset thickness.

[0020] In some embodiments of the first aspect, after the mold hole is cut on the template, the method further includes:

[0021] The template part and the grinding jig are immersed in a cleaning liquid together to separate the template part from the grinding jig and remove residual adhesive on the surface of the template part.

[0022] In some embodiments of the first aspect, before grinding the template member to a preset thickness, the method further includes: performing surface treatment on the template member.

[0023] In some embodiments of the first aspect, the method for preparing a nano-bulk having a desired grain size comprises:

[0024] Extruding the raw material through an extrusion channel provided on an extrusion die at a rated pressure; the extrusion channel comprises a first straight line segment, a corner segment and a second straight line segment which are connected in sequence, and the first straight line segment and the second straight line segment are arranged at an angle;

[0025] The above steps are repeated to obtain a nano-block with a grain size corresponding to the number of repetitions.

[0026] In the second aspect, the present application also provides a micro mold, which is prepared by the micro mold preparation method described in any one of the first aspect and any optional embodiments thereof, and the micro mold includes at least two stacked template parts, the template parts are provided with mold holes, and the mold holes on all the template parts are interconnected to form a mold cavity.

[0027] The preparation method of the micro-mold and the beneficial effect of the micro-mold provided by the present application are: after cutting out the template parts on the nano block with the required grain size, the template parts are then ground and cut in sequence to form template parts corresponding to different positions of the micro-mold, and finally the micro-mold is formed by stacking and fixing multiple template parts. Compared with the prior art, cutting the template parts and grinding the template parts are relatively simple, and the shape of the mold hole cut out on the template parts is also more stable. The micro-mold formed by stacking and fixing multiple template parts has good structural stability, and the cavity is not easy to deform, thereby reducing the difficulty of preparing the micro-mold, not only facilitating the control of the grain size of each part of the micro-mold, improving the structural strength of the micro-mold, but also ensuring the shape and precision of the cavity in the micro-mold. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0029] Figure 1 This is a schematic structural diagram of a micro mold in an exemplary embodiment of the present application;

[0030] Figure 2 is a flow chart of a method for preparing a micro mold in an exemplary embodiment of the present application;

[0031] Figure 3 This is a schematic structural diagram of an extrusion die in an exemplary embodiment of the present application;

[0032] Figure 4 It is a schematic structural diagram of cutting a template member from a raw material in an exemplary embodiment of the present application;

[0033] Figure 5 A schematic diagram of a structure for cutting a template member from a raw material in another exemplary embodiment of the present application;

[0034] Figure 6 This is a schematic diagram of a structure in which a template is fixed to a grinding jig in an exemplary embodiment of the present application;

[0035] Figure 7 It is a schematic structural diagram of a femtosecond laser ablation device in an exemplary embodiment of the present application;

[0036] Figure 8 An exploded view of a micro mold formed by laminating multiple layers of workpieces in an exemplary embodiment of the present application.

[0037] Among them, the reference numerals in the figure are:

[0038] 100-micro mold; 101-cavity;

[0039] 200-extrusion die; 210-die body; 211-extrusion channel; 220-pressing head;

[0040] 300-raw materials;

[0041] 400-nanometer bulk;

[0042] 500-template piece; 501-hole;

[0043] 600-Grinding fixture;

[0044] 700 - femtosecond laser ablation device; 710 - femtosecond laser; 720 - attenuation plate; 730 - shutter; 740 - total reflection mirror; 750 - focusing objective lens; 760 - motion platform; 761 - driving mechanism; 770 - controller; 780 - charge coupled device. DETAILED DESCRIPTION

[0045] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0046] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0047] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0048] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0049] In a first aspect, the present invention provides a method for preparing a micro mold 100. Figure 1 As shown, the prepared micro mold 100 is provided with a cavity 101, which can be through-set or non-through-set, and when used, parts of corresponding shapes are formed inside the cavity 101. It is understandable that the shapes of the micro mold 100 and the cavity 101 can be arbitrary.

[0050] like Figure 2 As shown, the method for preparing the micro mold includes steps 101 to 106.

[0051] In step 101 , a nano-bulk having a desired grain size is prepared.

[0052] The nano block is a nano-scale material that can be prepared by changing the grain size inside the metal material. The raw material for preparing the nano block can be pure copper, pure aluminum, pure nickel, or an alloy of at least two of the above materials, or other metal materials with good plasticity and processing properties. In addition, according to the specific performance requirements of the micro mold, the raw material 300 material with trace alloy elements added or subjected to specific heat treatment can be used to further optimize the performance of the micro mold.

[0053] Grain size refers to the average size of a single grain inside a material. A smaller grain size can improve the hardness and wear resistance of the micro mold, thereby extending the service life of the micro mold. Nano blocks with a suitable grain size can be prepared according to the use requirements of the micro mold.

[0054] In some embodiments, a method of preparing a nano-bulk having a desired grain size may include:

[0055] Extruding the raw material through the extrusion channel of the extrusion die at a rated pressure;

[0056] The raw material is repeatedly extruded for multiple times to obtain a nano-block with a grain size corresponding to the number of extrusion times.

[0057] Specifically, Figure 3As shown, the extrusion die 200 includes a die body 210 and a pressing head 220. The die body 210 is provided with an extrusion channel 211. The extrusion channel 211 includes a first straight segment 211a, a corner segment 211b and a second straight segment 211c. The first straight segment 211a and the second straight segment 211c are respectively connected and arranged at two ends of the corner segment 211b. The end of the first straight segment 211a away from the corner segment 211b is opened as the entrance of the extrusion channel 211, and the end of the second straight segment 211c away from the corner segment 211b is opened as the outlet of the extrusion channel 211. The central angle corresponding to the corner segment 211b can be arbitrary. In this embodiment, the central angle corresponding to the corner segment is 90°, that is, the first straight segment 211a and the second straight segment 211c are arranged perpendicular to each other.

[0058] The shape of the raw material 300 can be cylindrical or other shapes. The cross-sectional shape of the extrusion channel 211 is the same as that of the raw material 300, so that the raw material 300 can enter the extrusion channel 211. The pressure head 220 is movably arranged at the entrance of the extrusion channel 211, and can push the raw material 300 from the entrance into the extrusion channel 211 at a rated pressure, so that the raw material 300 passes through the first straight segment 211a, the corner segment 211b and the second straight segment 211c in sequence. When the raw material 300 passes through the corner segment 211b, shear deformation occurs, so that the coarse grains inside the raw material 300 are crushed and become smaller. After the raw material 300 is deformed by the corner segment 211b, it enters the second straight segment 211c and is restricted by the shape of the second straight segment 211c, so that the shape of the raw material 300 after being extruded is basically the same as the shape before being extruded, so that the raw material 300 can enter the extrusion channel 211 again and be repeatedly extruded. Among them, the pressure source of the pressure head 220 can be hydraulic pressure or air pressure.

[0059] By repeatedly extruding the raw material 300, the strain of each deformation of the raw material 300 is accumulated and superimposed to obtain a larger total strain, thereby crushing the coarse grains in the raw material 300 into smaller ultrafine grains. It can be understood that the grain size of the nano block finally obtained by repeatedly extruding the raw material 300 for different times is also different, and nano blocks with different grain sizes can be prepared by changing the number of extrusions of the raw material 300.

[0060] For example, when pure copper is used as the raw material 300, the grain size inside the raw material 300 can reach the ultrafine grain level by repeatedly extruding the raw material 300 4 times, and as the number of extrusions continues to increase, the grain size of the raw material 300 will continue to be refined and uniform. When the extrusion is repeated 8 times, the grain size of the raw material 300 reaches the minimum. At this time, the grain size of the raw material 300 changes less when the number of extrusions continues to increase. Therefore, nano blocks with different grain sizes can be prepared by repeatedly extruding the raw material 4 times, 6 times, or 8 times.

[0061] In addition, it can be understood that when a cylindrical raw material is used, the nanoblock obtained after extruding the raw material multiple times is also cylindrical.

[0062] In step 102 , a template piece is cut out from the nano block.

[0063] Specifically, a wire cutting device can be used to cut out the template on the nano block. Figure 4 As shown, when the nano block 400 is cylindrical, a rectangular or other shaped template 500 can be cut along the axial direction of the nano block 400. The maximum length of the template 500 obtained is the axial length of the nano block 400, and the maximum width can be approximately the diameter of the nano block, thereby obtaining a template 500 with a larger area. Figure 5 As shown, when cutting the template part 500, it is also possible to cut along the radial direction of the nano block 400 so as to cut out a circular template part 500, thereby saving the material of the nano block 400. Moreover, when multiple template parts 500 of the same grain size are required, multiple template parts 500 can be cut from the same nano block 400.

[0064] The shape of the template element 500 should be the same as the cross-sectional outer contour of the micro mold 100 . The template element 500 can be used as a part of the micro mold 100 , so that the micro mold 100 can be formed by overlapping a plurality of template elements 500 .

[0065] In step 103, at least two template members are ground to respective corresponding preset thicknesses.

[0066] Among them, at least two template components can be cut from the same nanosecond block, or can be cut separately from nanosecond blocks with different grain sizes, which can be determined according to the grain size required for each template component.

[0067] By grinding the template part, the thickness of the template part can be reduced and the surface quality of the template part can be improved, which is convenient for the subsequent superposition and fixation of the template part. The preset thickness of different template parts can be the same or different. The size of the preset thickness can be adaptively set based on the subsequent processing requirements of the template part, the height of the micro mold, and the number of template parts constituting the micro mold, so that the height of the base formed by the superposition of multiple template parts is the same as the design requirements.

[0068] In some embodiments, the method of grinding the template pieces to their respective corresponding preset thicknesses may include:

[0069] Fix the template part on the grinding jig;

[0070] The template member is ground multiple times in sequence using a plurality of grinding pieces with increasing mesh sizes until the thickness of the template member reaches the respective corresponding preset thicknesses.

[0071] like Figure 6 As shown, the grinding jig 600 can be a platform of any shape, and the upper surface of the grinding jig 600 is required to be flat, so that the template member 500 can be flatly attached to the upper surface of the grinding jig 600 to avoid bending and deformation of the template member 500 during the grinding process. In some embodiments, an adhesive can be used to fix the template member 500 on the grinding jig 600. For example, the template member 500 is bonded to the grinding jig 600 using 502 glue to keep the template member 500 in a fixed position during grinding.

[0072] The grinding piece can be sandpaper. When grinding the template 500, 1500#, 2000# and 3000# sandpaper can be used in sequence to grind the template 500. The larger the mesh number of the sandpaper, the finer the grinding effect, and the lower the surface roughness of the template 500 after grinding. In addition, the grinding piece can also be a grinding wheel or an oil stone.

[0073] Specifically, you can use 1500# sandpaper to rough grind the template to quickly remove the larger uneven parts on the template surface, then use 2000# sandpaper to medium grind the template, and finally use 3000# sandpaper to fine grind the template to obtain a template with high precision and smooth surface. The step-by-step grinding method not only improves the grinding efficiency, but also ensures that the thickness and surface quality of the template can meet the design requirements, which is convenient for subsequent processing of the template.

[0074] During the grinding process, it should be ensured that the contact between the grinding piece and the template piece is uniform to avoid excessive local pressure causing scratches or uneven wear on the template piece. In addition, the grinding piece should be kept clean during grinding to avoid sand particles falling off and contaminating the surface of the template piece. Before and after each replacement of the grinding piece, the surface of the template piece can be cleaned with a dust-free cloth or a special cleaning agent to ensure the uniformity and consistency of the grinding effect. The grinding process can be performed manually or automatically by a grinding device, which is not limited in this embodiment.

[0075] In some embodiments, the template member may be surface treated before being ground to a preset thickness.

[0076] Specifically, after cutting the template part out on the nano block, the surface of the template part can be repeatedly polished with 1500# sandpaper to remove the oxide layer on the surface of the template part. The template part is then soaked in anhydrous ethanol and cleaned with an ultrasonic cleaner for 10 to 15 minutes until the surface of the template part is clean and bright, so that there is no impurity on the surface of the template part in the subsequent grinding, avoiding interference with the grinding and reducing the occurrence of defects in the grinding.

[0077] In step 104, a mold hole is cut in each template piece.

[0078] The shape of the mold hole is the same as the cross-sectional shape of the mold cavity at the micro-mold position corresponding to the template part, so that after the multiple template parts are stacked in sequence, the multiple mold holes are connected to form the mold cavity.

[0079] In some embodiments, a femtosecond laser may be used to cut the holes in the template piece.

[0080] Specifically, a femtosecond laser ablation device may be used to perform femtosecond laser cutting on the template. Figure 7 As shown, the femtosecond laser ablation device 700 includes: a femtosecond laser 710 , an attenuation plate 720 , a shutter 730 , a total reflection mirror 740 , a focusing objective lens 750 and a motion platform 760 .

[0081] The central wavelength of the femtosecond laser 710 is 800nm, the pulse width is 35fs, the maximum average power is 4W, and the maximum repetition frequency is 1kHz. The output end of the femtosecond laser 710 is connected to the input end of the attenuation plate 720, the output end of the attenuation plate 720 is connected to the input end of the shutter 730, the output end of the shutter 730 is connected to the reflection surface of the total reflection mirror 740, and is reflected to the input end of the focusing lens 750 through the total reflection mirror 740. The output end of the focusing lens 750 is set downward, and the motion platform 760 is located below the focusing lens 750. The motion platform 760 is provided with a driving mechanism 761, which can drive the motion platform 760 to move in the X-axis, Y-axis or Z-axis direction.

[0082] The femtosecond laser 710 also includes a controller 770 and a charge coupled device 780. The controller 770 may be a computer. The controller 770 is connected to the shutter 730 and a driving mechanism 761 of the motion platform 760. On the one hand, the opening and closing of the shutter 730 may be controlled by the controller 770, and on the other hand, the motion of the motion platform 760 may be controlled by the driving mechanism 761.

[0083] During operation, the template 500 and the grinding jig 600 are placed on the upper surface of the motion platform 760, so that the template 500 is below the focusing lens 750. The femtosecond laser emitted by the femtosecond laser 710 passes through the attenuation plate 720, the shutter 730, the total reflection mirror 740 and the focusing lens 750 in sequence, and then irradiates one side of the template 500. First, the movement of the motion platform 760 on the Z axis is adjusted to make the light plate of the femtosecond laser accurately fall on the surface of the template 500, and then the controller 770 controls the motion platform 760 to drive the template 500 to move according to the preset trajectory, so that the femtosecond laser cuts the corresponding contour shape on the template 500, thereby forming a mold hole of the corresponding shape on the template 500.

[0084] The controller 770 is also connected to the other side of the total reflective mirror 740 through a charge coupled device 780, so that the spot position and energy distribution during the laser ablation process can be monitored in real time through the charge coupled device 780, thereby realizing accurate monitoring and adjustment of the ablation process. The charge coupled device 780 can capture image information during the laser ablation process and transmit this information to the controller 770, which adjusts the parameters of the laser in real time according to the image information to ensure that the ablation effect reaches the expected goal.

[0085] In some embodiments, when a femtosecond laser is used to cut a mold hole on a template, the preset thickness is no greater than 50 μm to ensure that the femtosecond laser can penetrate the template and cut the mold hole. In this embodiment, the preset thickness is 30-50 μm.

[0086] In some embodiments, the initial thickness of the template member is 5 to 20 times the thickness of the template member.

[0087] The initial thickness of the template part is the thickness of the template part after it is cut from the nano block and before it is ground. By making the initial thickness of the template part larger, on the one hand, the difficulty of cutting the template part on the nano block can be reduced, and on the other hand, the template part has sufficient thickness for multiple grinding, so that the template part can be accurately ground to the preset thickness, ensuring the grinding accuracy and surface quality of each template part.

[0088] In some embodiments, after the mold hole is cut on the template part, the template part and the grinding jig can be immersed in a cleaning liquid together to separate the template part from the grinding jig and clean the residual adhesive on the surface of the template part.

[0089] The cleaning liquid can be an alcohol solution, which can be used to weld the adhesive between the template and the grinding fixture by immersion, thereby not only achieving lossless separation of the template, but also cleaning the adhesive remaining on the surface of the template, making the surface of the workpiece clean and tidy.

[0090] In step 105, at least two template members are stacked in sequence, and the mold holes on all the template members are connected to form a mold cavity.

[0091] The base of the micro-mold is fixed, and at least two mold holes are connected to each other to form a mold cavity.

[0092] Specifically, Figure 7 As shown, by preparing a plurality of template parts 500, the grain size of each template part 500 can be the same or different, and the outer contour shape of each template part 500 corresponds to the outer contour shape of the cross section of the micro mold 100 at different heights, and the contour of the mold hole 501 of each template part 500 corresponds to the contour shape of the cross section of the cavity 101 at different heights. According to the position of the micro mold 100 corresponding to each template part 500, the plurality of template parts 500 are stacked and arranged in sequence, and the plurality of mold holes 501 are interconnected to form the cavity 101 of the micro mold 100.

[0093] In step 106, each two adjacent template members are fixedly connected to form a micro-mold.

[0094] Among them, laser welding technology can be used between two adjacent template members 500. By accurately controlling the intensity and position of the laser beam, micron-level welding accuracy can be achieved between the template members 500. Laser welding can not only ensure the close bonding between the layers, but also will not cause thermal damage to the internal structure of the micro mold 100, thereby maintaining the high precision and high stability of the micro mold 100.

[0095] In summary, the preparation method of the micro-mold provided by the present invention obtains a nano-block of the required grain size by repeatedly extruding the raw materials for multiple times, and after cutting out the template parts on the nano-block, the template parts are successively ground and femtosecond laser cut to obtain template parts corresponding to different positions of the micro-mold, and finally multiple template parts are stacked and fixed to form a micro-mold. This not only makes it easy to control the grain size of the micro-mold and ensure the structural strength of the micro-mold, but also can ensure the shape and precision of the cavity in the micro-mold. The process is simple, easy to operate, and effectively reduces the difficulty of preparing the micro-mold.

[0096] In a second aspect, an embodiment of the present application provides a micro mold, which is prepared by the micro mold preparation method in the embodiment of the first aspect.

[0097] Specifically, Figure 1 and Figure 7As shown, the micro mold 100 provided in the present application includes at least two stacked template members 500 , the template member 500 is provided with mold holes 501 , and at least two mold holes 501 are interconnected to form a mold cavity 101 .

[0098] The grain size of each template 500 is controlled by extruding the raw material 300 at different times, and the grain sizes of the templates 500 at different positions can be the same or different. Figure 7 From left to right, the grain sizes of the template parts 500 are 7 μm, 0.79 μm, 0.51 μm and 0.51 μm, respectively. In addition, the mold holes 501 on the template parts 500 are formed by femtosecond laser cutting, which has high precision. The micro mold 100 formed by stacking multiple template parts 500 has the advantages of easy processing, high precision, high surface quality and high mechanical properties.

[0099] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a micro mold, characterized in that: include: preparing nano-bulks with desired grain sizes; cutting a template piece on the nano block; Grinding the thickness of at least two of the template members to respective corresponding preset thicknesses; Cutting a mold hole on the template; At least two of the template members are stacked in sequence, and the mold holes on all the template members are interconnected to form a mold cavity; Each two adjacent template members are fixedly connected to form the micro-mold.

2. The method for preparing a micro mold according to claim 1, characterized in that: Grinding the thickness of the template members to respective corresponding preset thicknesses comprises: Fixing the template member to a grinding jig; The template material is ground multiple times in sequence using a plurality of grinding pieces with increasing mesh sizes until the thickness of the template reaches the corresponding preset thickness.

3. The method for preparing a micro-mold according to claim 2, characterized in that: The template is fixed to the grinding tool using an adhesive.

4. The method for preparing a micro-mold according to claim 2, characterized in that: The mold hole is cut on the template member using a femtosecond laser.

5. The method for preparing a micro-mold according to claim 4, characterized in that: The preset thickness is no greater than 50 μm.

6. The method for preparing a micro mold according to claim 5, characterized in that: The thickness of the template member before grinding is 5 to 20 times the preset thickness.

7. The method for preparing a micro-mold according to claim 4, characterized in that: After the mold hole is cut on the template, the method further comprises: The template part and the grinding jig are immersed in a cleaning liquid together to separate the template part from the grinding jig and remove residual adhesive on the surface of the template part.

8. The method for preparing a micro-mold according to any one of claims 1 to 7, characterized in that: Before grinding the template member to a preset thickness, the method further includes: performing surface treatment on the template member.

9. The method for preparing a micro-mold according to any one of claims 1 to 7, characterized in that: The method for preparing a nano-block having a desired grain size comprises: Extruding the raw material through an extrusion channel provided on an extrusion die at a rated pressure; the extrusion channel comprises a first straight line segment, a corner segment and a second straight line segment which are connected in sequence, and the first straight line segment and the second straight line segment are arranged at an angle; The above steps are repeated to obtain a nano-block with a grain size corresponding to the number of repetitions.

10. A micro mold, characterized in that: The micro mold is prepared by the preparation method of any one of claims 1-9, wherein the micro mold comprises at least two stacked template parts, the template parts are provided with mold holes, and the mold holes on all the template parts are interconnected to form a mold cavity.

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