Local sanding method of uneven thickness mobile phone shell, mobile phone shell and preparation method

Abstract

The application provides a local sand wheel sanding method for a non-uniform thickness mobile phone shell, comprising: using a CNC controlled sand wheel to process the local thickness of the mobile phone shell; according to the design requirements of the final product, using the CNC controlled sand wheel to cut the mobile phone shell after the local thickness processing; using the CNC controlled processing path of a plurality of profiled resin sand wheels to grind and sand the sanding area of the mobile phone shell fixed in the jig; printing protective oil on the sanding surface and polishing the non-sanding area using a grinding machine; and chemically strengthening the sanding and polished mobile phone shell. Through the CNC size processing and different profiled resin sand wheel processing, the application can realize the sanding of the mobile phone shell with non-uniform thickness and thickness step positions, and can ensure the R value of the step position. The sanding shape is controlled by CNC programming, and the sanding of various shape surfaces of mobile phone shells of various materials can be realized. The process is simple, the size precision of the sanding area is high, no chemical solvent is used and recovered and treated, the environment is friendly, and the cost is high.

Description

Technical Field

[0001] This application relates to the field of glass surface treatment technology, and in particular to a method for partial sanding with a grinding wheel for mobile phone cases of unequal thickness, the mobile phone case and its preparation method. Background Technology

[0002] Current methods for creating a frosted finish on mobile phone cases primarily employ sandblasting and chemical etching. Sandblasting involves first CNC machining the phone case to the desired dimensions and cutouts. Then, the non-frosted areas of the surface are protected with a protective oil or film. Next, a nozzle propels fine abrasive particles (diamond or quartz sand) at high speed and direction onto these unprotected areas (the frosted areas), causing cross-shaped micro-cracks and the removal of tiny, shell-like fragments. This results in an opaque or semi-transparent matte finish, achieving the frosted effect. Chemical etching, on the other hand, involves CNC machining to the desired dimensions and cutouts, followed by protection of the non-frosted areas with a protective oil or film. Then, a chemical solution, such as hydrofluoric acid, is sprayed onto the surface, etching the frosted areas. The resulting insoluble reactant crystals accumulate and adhere to the surface, hindering further corrosion. This non-uniform erosion creates a semi-transparent or opaque matte finish, achieving the frosted effect.

[0003] Currently, both sandblasting and chemical etching processes achieve their desired abrasive effects by spraying abrasive particles or solvents onto the entire surface of the workpiece. These methods inherently lack the ability to control localized surface treatment, necessitating the application of protective oil or films to non-processed areas. The shape and dimensional accuracy of the abrasive-coated areas are heavily dependent on the precision of the protective oil (film), resulting in poor accuracy control. Damage to the protective oil (film) can lead to sand overflow, and in cases of uneven thickness, the protective oil (film) may not adequately cover the steps, compromising the radius (R) value and making it difficult to accurately control sandblasting at these areas. Subsequent processes are required to repair the damaged R value. Furthermore, the high-speed impact of sandblasting particles can easily damage the edges of the protective oil (film), resulting in poor edge sandblasting or incorrect abrasive dimensions. When chemical etching is used to process workpieces of varying thickness with stepped sections, there is an accumulation of chemical solution at the stepped sections, making it difficult to accurately control the R-value and the sanding effect at the stepped sections. Furthermore, the chemical solvents require additional recycling and treatment, which is subject to environmental restrictions. In some regions, it is not possible to set up factories using this process, and recycling and treatment also increase processing costs.

[0004] Therefore, a new solution is needed. Summary of the Invention

[0005] The purpose of this invention is to provide a method for localized sanding with a grinding wheel for mobile phone cases of unequal thickness.

[0006] Therefore, this application provides a method for partial sanding with a grinding wheel for mobile phone cases of unequal thickness, comprising the following steps:

[0007] Step S1: Use CNC-controlled grinding wheels to perform local thickness processing on the phone case;

[0008] Step S2: According to the final product design requirements, use CNC-controlled grinding wheels to cut the phone case after the local thickness processing.

[0009] Step S3: Use CNC to control the processing path of various contour resin grinding wheels to grind and sand the frosted area of ​​the mobile phone case fixed in the fixture.

[0010] Step S4: Apply protective oil to the frosted surface and polish the non-frosted areas using a grinder.

[0011] Step S5: Chemically strengthen the sandblasted and polished phone case.

[0012] In one feasible implementation, the grinding wheel used in step S1 is a common precision carving grinding wheel, and the local thickness processing includes roughing the stepped surface and finely shaping the stepped surface.

[0013] In one feasible implementation, the grinding wheel used in step S2 is a common precision carving grinding wheel, and the cutting process includes cutting the outline, hole positions, and bevels.

[0014] In one feasible implementation, step S3 includes:

[0015] Step S31: Use CNC-controlled bevel-shaped resin grinding wheel to process and sand the bevel;

[0016] Step S32: Use a resin grinding wheel with CNC control to sand the plane and step of the sanded area. The resin grinding wheel consists of two parts: an edge area and a plane area that are shaped to the step.

[0017] In one feasible implementation, in step S4, the material of the brush for body polishing is white twisted wire, the material of the brush for bevel polishing is sheepskin, and the material of the grinding powder is rare earth metal oxide with added chemical elements.

[0018] In one feasible implementation, in step S5, chemical enhancement is performed using NaNO3 solution and KNO3 solution.

[0019] In one feasible implementation, step S5, after chemical strengthening, further includes: printing gray ink on the frosted area.

[0020] In one feasible implementation, the material of the phone case is selected from one of injection-molded PC board, glass, and sapphire.

[0021] According to another aspect of the present invention, a method for preparing a mobile phone case with unequal thickness is also provided, comprising the following steps:

[0022] Preparation of colored explosion-proof film;

[0023] The phone case, which is processed according to the local sanding method of uneven thickness phone case as described above, is vacuum bonded to the color explosion-proof film to remove bubbles.

[0024] The bonded product is then vacuum electroplated with an anti-fingerprint film.

[0025] According to another aspect of the present invention, a phone case with unequal thickness is also provided, which is prepared by the method for preparing an unequal thickness phone case as described above.

[0026] The technical solution of this application has at least the following beneficial effects:

[0027] This application provides a method for partial sanding of mobile phone cases with unequal thickness. A resin grinding wheel mounted on a CNC machine is used to grind the surface of the workpiece to form a frosted surface. The shape and precision of the frosted area are programmed by the CNC according to the drawing, eliminating the need for separate protection of non-sanded areas with protective oil (film). The sanded area exhibits high processing precision, good edge finish, and no sand overflow defects. When processing stepped areas, the sanding quality is guaranteed while ensuring the R-value of the step, eliminating the need for subsequent separate R-value repair. The process does not require the use of environmentally unfriendly chemical solvents or additional chemical solution recovery treatment. The processing steps are simple, the shape accuracy and effect of the frosted area are excellent, unaffected by differences in workpiece thickness, and the manufacturing cost is low, greatly improving production efficiency. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort:

[0029] Figure 1 The diagram shown is a flowchart of a method for partial sanding of mobile phone cases with unequal thickness provided in an embodiment of the present invention. Detailed Implementation

[0030] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Typical embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0032] The overall concept of this invention is as follows: Addressing the limitations of existing surface sanding methods that use nozzles to spray abrasive particles or solvents onto the surface of a workpiece, which cannot control the localized processing of the workpiece surface, requiring the application of protective oil or films in non-processed areas for localized protection; the shape and dimensional accuracy of the sanded area are controlled by the precision of the protective oil (film), resulting in poor precision control; damage to the protective oil (film) leads to sand overflow, and in the presence of uneven thicknesses, the protective oil (film) cannot adequately cover the steps, failing to guarantee the R-value of the steps and accurately control whether sanding is applied to the steps, necessitating additional processing to repair the damaged R-value. This invention provides a localized sanding method for mobile phone cases with uneven thicknesses, utilizing a CNC-machined resin grinding wheel to grind the workpiece surface to form a frosted surface. The shape and precision of the frosted area are machined by CNC according to the drawing, eliminating the need for separate protection of non-frosted areas with protective oil (film). The frosted area has high machining precision, good edge effect, and no sand overflow defects. When machining the step position of the product, the R value of the step position is well guaranteed while ensuring the quality of the frosting, eliminating the need for subsequent separate R value repair. No environmentally unfriendly chemical solvents are used in the processing, and no additional chemical solution recycling treatment is required. The processing steps are simple, the shape accuracy and effect of the frosted area are excellent, and it is not affected by the thickness difference of the processed part. The production cost is low, which greatly improves production efficiency.

[0033] To better understand the above technical solutions, the following will describe the above technical solutions in detail with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solutions of this application, rather than limitations on the technical solutions of this application. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0034] Figure 1 The diagram shown is a schematic flowchart of a method for partial sanding with a grinding wheel for mobile phone cases of unequal thickness provided in an embodiment of the present invention. Figure 1As shown, the present invention provides a method for partial sanding with a grinding wheel for mobile phone cases of unequal thickness, comprising the following steps:

[0035] Step S1: Use CNC-controlled grinding wheels to perform local thickness processing on the phone case;

[0036] Specifically, in one embodiment of the present invention, the phone case to be processed is a non-uniform thickness phone case, and its material can be glass, sapphire, injection molded parts, or other materials that can be processed by grinding wheels. The overall phone case structure design can include various phone case structures such as camera hole, viewing window area, non-frosted area, 2.5D bevel, partial or full-surface ink printing, 3D curved surface, etc.

[0037] Specifically, in one embodiment of the present invention, a mobile phone case with protective oil on both sides and uniform thickness is locally processed using a CNC machine, so that the processed thickness has a certain thickness margin compared with the final shipped product thickness. The grinding wheel used is a common precision carving wheel, and the thickness processing mainly includes roughing and finely shaping the stepped surface.

[0038] Step S2: According to the final product design requirements, use CNC-controlled grinding wheels to cut the phone case after the local thickness processing.

[0039] Specifically, in one embodiment of the present invention, in step S2, the thickened phone case is machined using a CNC machine with a certain machining allowance through ordinary precision carving wheel cutting, according to the final product design requirements. The machining of the holes includes rough drilling and fine drilling; the machining of the 2.5D bevel includes machining the lower bevel + body + chamfer and machining the upper bevel + body + chamfer.

[0040] Step S3: Use CNC to control the processing path of various contour resin grinding wheels to grind and sand the frosted area of ​​the mobile phone case fixed in the fixture.

[0041] Specifically, in one embodiment of the present invention, the local sanding uses various contoured resin grinding wheels to grind and sand the sanding area of ​​the mobile phone case fixed in the fixture. The structure of the local sanding area can be a thickness step, a 2.5D arc-shaped bevel, a uniform plane, a sloped surface with a thickness gradient, a 3D mobile phone case surface, etc. The shape design of the local sanding can be of various forms. The size and structure of the sanding area are designed and processed by the machining path of the CNC programmed grinding wheel in combination with the use of different contoured resin grinding wheels. Specifically, step S3 includes:

[0042] Step S31: Use CNC-controlled bevel-shaped resin grinding wheel to process and sand the bevel;

[0043] Step S32: Use a resin grinding wheel with CNC control to sand the plane and step of the sanded area. The resin grinding wheel consists of two parts: an edge area and a plane area that are shaped to the step.

[0044] Step S4: Apply protective oil to the frosted surface and polish the non-frosted areas using a grinder.

[0045] Specifically, in one embodiment of the present invention, a protective oil is applied to the frosted surface, and the non-frosted areas are polished using a grinding mill. The polishing includes body polishing and bevel polishing. The brush material for body polishing is white twisted filament, and the grinding powder is a rare earth metal oxide with added chemical elements. The brush material for bevel polishing is sheepskin, and the grinding powder is a rare earth metal oxide with added chemical elements.

[0046] Step S5: Chemically strengthen the sandblasted and polished phone case.

[0047] Specifically, in one embodiment of the present invention, the frosted and polished mobile phone case is chemically strengthened twice by using NaNO3 solution and KNO3 solution to enhance the strength of the mobile phone case.

[0048] Furthermore, in one embodiment of the present invention, after chemical strengthening, a layer of gray ink can be printed on the frosted area of ​​the mobile phone case, with an ink thickness of 4-8 μm.

[0049] This invention utilizes CNC machining and different contour resin grinding wheels to achieve sandblasting on phone cases with varying thicknesses and thickness steps, while ensuring the R-value of each step. The sandblasting shape is controlled by CNC programming, allowing for sandblasting on various shapes and surfaces of phone cases made of different materials. The grinding wheel sandblasting process is simple; when sandblasting specific areas, there is no need to repeatedly apply protective oil (film) to non-sandblasted areas, eliminating the problem of poor sandblasting in non-sandblasted areas due to inadequate protective oil (film). The sandblasting area achieved through localized grinding wheel sandblasting has high dimensional accuracy, clear boundaries between sandblasted and non-sandblasted areas, and consistent sandblasting effect at the edges with the main body of the sandblasted area, resulting in superior edge sandblasting performance. It eliminates the use and recycling of chemical solvents, making it environmentally friendly and cost-effective.

[0050] This invention also provides a method for preparing a mobile phone case with unequal thickness, comprising the following steps:

[0051] Step S10: Prepare the colored explosion-proof film;

[0052] Specifically, in one embodiment of the present invention, the production of the color-coated explosion-proof film mainly includes UV brushed texture production, electroplating, printing the base color on the coating layer, and laser engraving and cutting to the required shape. The color film can achieve various color effects, including but not limited to monochrome, matte, gradient, high-gloss, high-gloss gradient, and zoned colors, providing design space for mobile phone appearance design.

[0053] Step S20: Vacuum bond the phone case processed according to the above-mentioned partial sanding method for uneven thickness phone cases with the color explosion-proof film to remove bubbles;

[0054] Step S30: Vacuum electroplating an anti-fingerprint film onto the bonded product.

[0055] In this embodiment, by using various structures and frosted areas of the phone case, combined with color films that fit different designs, the design space for the phone's appearance and structure is greatly improved.

[0056] The following is an example of a 2.5D glass phone case with uneven thickness and partial frosted finish. The specific production steps are as follows.

[0057] 1. Preparation of colored explosion-proof film

[0058] 1. UV-etched texture fabrication: The non-OCA side of the explosion-proof film is printed with a UV-etched mold onto the film using a UV-etching mold. After UV curing, a stable texture is formed. UV curing energy: 200-2000mJ, UV layer thickness: 4-16um, OCA thickness: 10um-30um, PET substrate thickness: 50-75um.

[0059] 2. Electroplating: Electroplating is performed on the explosion-proof film after UV transfer printing to improve the brightening effect;

[0060] Depending on the desired appearance, ion sputtering or evaporation coating processes can be used to coat the product with a single or multiple layers.

[0061] 3. Print the base color on the coating layer. Depending on the window design and desired appearance, 2 to 8 layers of color or a pure black base can be applied, with each layer being 5 to 8 μm thick. Taking light blue as an example, print three layers of black oil and one layer of DM varnish on the non-frosted areas of the film, each layer being 5 to 8 μm thick. Print five layers of blue oil, two layers of gray oil, and one layer of varnish on the frosted areas, each layer being 5 to 8 μm thick.

[0062] Taking gray as an example, three layers of black varnish and one layer of DM varnish are printed on the non-frosted areas of the film, each layer being 5-8µm. Three layers of black varnish and one layer of varnish are printed on the frosted areas, each layer being 5-8µm.

[0063] For the remaining colors, three layers of black varnish and one layer of DM varnish are printed on the non-frosted areas of the film, each layer being 5-8µm. Four layers of corresponding color layers are printed on the frosted areas: two layers of gray varnish and one layer of varnish, each layer being 5-8µm.

[0064] 4. Perform laser engraving and cutting to fit the required shape.

[0065] 2.5D Uneven Thickness Partial Sandblasting Processing for Mobile Phone Cases

[0066] 1. Local Thickness Processing: Incoming glass with uniform thickness and protective oil on both sides is locally thickened using CNC equipment. The original material thickness is 1mm, and the frosted area thickness is 0.6mm. The processed thickness has a certain allowance compared to the final finished product thickness. The grinding wheel used is a standard precision carving wheel. The roughing step surface processing parameters are: grinding wheel diameter: Ф48mm; diamond grit size: 325#; rotation speed: 2000±300rpm; processing speed: 350±50mm / min; processing depth: 0.3mm; processing allowance: 0.1mm.

[0067] 2. Grinding wheel diameter for precision step surface machining: Ф48mm; diamond grit size: 800#; rotation speed: 2000±300rpm; machining speed: 230±20mm / min; machining depth: 0.05mm;

[0068] 3. After the glass thickness is processed, it is cut using CNC machining according to the final product design requirements, with a certain machining allowance, holes, and 2.5D bevels. Machining dimensions: grinding wheel diameter: Ф11.4mm, abrasive particle size: 325#, rotation speed: 20000±300rpm, machining speed: 750±20mm / min, machining depth: 1.2mm, machining allowance: 0.2mm;

[0069] 4. Rough opening of the machining hole, grinding wheel diameter: Ф4m, diamond grit size: 325#, rotation speed: 20000±300rpm, machining speed: 300±20mm / min, machining allowance: 0.3mm;

[0070] 5. Precision drilling, grinding wheel diameter: Ф4mm, grinding wheel grit: 600#, rotation speed: 20000±300rpm, machining speed: 400±20mm / min.

[0071] 6. Machining the lower bevel, body, and chamfer: The lower bevel is machined using a contour grinding wheel. Grinding wheel diameter: Ф4.4mm, R1.2mm, diamond abrasive particle size: 600#, rotation speed: 20000±300rpm, machining speed: 480±20mm / min, contour body thickness: 0.12mm, the starting position of the contour lower bevel is 1.57mm from the edge, and the bevel machining thickness is 0.33mm.

[0072] 7. Machining the upper bevel + chamfer + chamfer, grinding wheel diameter: Ф4.4mm, grinding wheel grit: 600#, rotation speed: 20000±300rpm, machining speed: 500±20mm / min, thickness of the chamfer in the contouring section: 0.13mm, the starting position of the lower bevel is 2.5mm from the edge, and the thickness of the bevel is 0.74mm.

[0073] 8. Sanding the lower bevel of the frosted area: The 2.5D bevel is machined and sanded using a CNC bevel profile resin grinding wheel. The resin grinding wheel used is a specially designed bevel profile grinding wheel with a diameter of Ф4.4mm, a diamond particle size of 200#, a porosity of 4%, a rotation speed of 2200±300rpm, and a machining speed of 380±20mm / min.

[0074] 9. Sanding the flat and stepped areas of the frosted region: Replace the resin grinding wheel with one that conforms to the stepped edge, and sand the flat and stepped areas of the frosted region. The resin grinding wheel used consists of two parts: the edge area conforming to the stepped edge and the flat area. Grinding wheel diameter: Ф90mm; diamond grit size: 200#; porosity: 4%; rotation speed: 2400±300rpm; machining depth: 0.05mm; machining speed: 310±20mm / min.

[0075] 3. Apply protective oil to the frosted surface, and polish the non-frosted areas with a grinder. For the body polishing, the brush material is white twisted wire, the processing time is 300±100s, the grinding powder concentration is 9±2be, and the grinding powder material is rare earth metal oxide with added chemical elements. For the bevel polishing, the brush material is sheepskin, the processing time is 800±200s, the grinding powder concentration is 9±2be, and the grinding powder material is rare earth metal oxide with added chemical elements.

[0076] IV. The frosted and polished glass is chemically strengthened to enhance the strength of the phone case. The parameters for the first strengthening are: NaNO3 concentration 45%, KNO3 concentration 55%, temperature 410±10℃, time 145±5min. The parameters for the second strengthening are: NaNO3 concentration 1%, KNO3 concentration 99%, temperature 390±10℃, time 15±5min.

[0077] 5. Print a layer of gray ink on the frosted glass area, with an ink thickness of 4-8 μm.

[0078] 6. Vacuum bonding and debubbling of the processed phone case and color film. Vacuum bonding pressure: 400~1200kgf, holding time: 3~10S, vacuum degree: 4.0~1.0*10-1Torr. Debubbling pressure: 900±300KPA, temperature: 50±10℃, time: 40min±20min.

[0079] 7. Vacuum electroplating an anti-fingerprint film onto the bonded product completes the manufacturing process.

[0080] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0081] Similarly, it should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, this method of disclosure should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into this detailed description, wherein each claim itself is a separate embodiment of the invention.

[0082] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0083] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

Claims

1. A method for partial sanding with a grinding wheel on mobile phone cases of unequal thickness, characterized in that, Includes the following steps: Step S1: Use CNC-controlled grinding wheel to perform local thickness processing on the phone case to form thickness steps; Step S2: According to the final product design requirements, use CNC-controlled grinding wheels to cut the phone case after the local thickness processing. Step S3: Using CNC control to control the processing paths of various contour resin grinding wheels, the frosted area of ​​the mobile phone casing fixed in the fixture is ground and sanded. Step S3 includes: Step S31: Use CNC-controlled bevel-shaped resin grinding wheel to process and sand the bevel; Step S32: Use a resin grinding wheel with CNC control to sand the plane and step of the sanded area. The resin grinding wheel is composed of two parts: the edge area and the plane area that are shaped to the step. Step S4: Apply protective oil to the frosted surface and polish the non-frosted areas using a grinder. Step S5: Chemically strengthen the sandblasted and polished phone case.

2. The method for partial sanding of mobile phone cases with unequal thickness according to claim 1, characterized in that, The grinding wheel used in step S1 is a common precision carving grinding wheel, and the local thickness processing includes roughing the stepped surface and finely shaping the stepped surface.

3. The method for partial sanding of mobile phone cases with unequal thickness according to claim 1, characterized in that, The grinding wheel used in step S2 is a common precision carving grinding wheel, and the cutting process includes cutting the outline, hole positions and bevels.

4. The method for partial sanding of mobile phone cases with unequal thickness according to claim 1, characterized in that, In step S4, the material of the brush for body polishing is white twisted wire, the material of the brush for bevel polishing is sheepskin, and the material of the grinding powder is rare earth metal oxide with added chemical elements.

5. The method for partial sanding of mobile phone cases with unequal thickness according to claim 1, characterized in that, In step S5, chemical enhancement is performed using NaNO3 solution and KNO3 solution.

6. The method for partial sanding of mobile phone cases with unequal thickness according to claim 1, characterized in that, In step S5, after chemical strengthening, the process further includes printing gray ink on the frosted area.

7. The method for partial sanding of mobile phone cases with unequal thickness according to claim 1, characterized in that, The material of the phone case is selected from one of injection-molded PC board, glass, and sapphire.

8. A method for preparing a mobile phone case with unequal thickness, characterized in that, Includes the following steps: Preparation of colored explosion-proof film; The phone case processed by the partial grinding wheel sanding method of the unequal thickness phone case according to any one of claims 1-7 is vacuum bonded to the color explosion-proof film to remove bubbles; The bonded product is then vacuum electroplated with an anti-fingerprint film.

9. A mobile phone case with unequal thickness, characterized in that, The phone case with unequal thickness is prepared using the preparation method described in claim 8.

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