A 3D curved glass cover plate processing process based on fine carving pretreatment and hot bending forming

Abstract

The application discloses a kind of 3D curved surface glass cover plate processing technology based on fine carving pretreatment and hot bending forming, belong to glass cover plate processing technical field.The application is made positioning mark, i.e.positioning hole in non-bending area in the fine carving pretreatment stage before hot bending forming, and fine carving finishing is carried out with the positioning mark as reference after hot bending, effectively avoids the positioning reference deviation problem caused by hot bending deformation, so that the size precision of final product reaches high standard requirement, overcome the technical problem that size is out of tolerance caused by hot bending deformation in traditional process, and fine carving pretreatment is only completed in non-bending area, without affecting the material integrity of bending area, cooperate with the hot bending mould with circular arc groove structure, so that the internal stress of glass four corners is effectively released in the hot bending process, avoid folding mark and deformation defect, greatly improve product appearance yield and structural strength.

Description

Technical Field

[0001] This invention relates to the field of glass cover processing technology, specifically a 3D curved glass cover processing technology based on precision carving pretreatment and hot bending forming. Background Technology

[0002] As consumer electronics products continue to demand higher aesthetics and better user experience, 3D curved glass covers have gradually become the mainstream configuration for high-end smartphones, smartwatches, and automotive display panels. Compared to traditional 2D or 2.5D glass covers, 3D curved glass covers can achieve a larger display area ratio, a smoother feel, and richer optical visual effects.

[0003] Currently, the mainstream processing flow for 3D curved glass covers typically includes processes such as material cutting, fine carving, grinding, cleaning, hot bending, polishing, tempering, and screen printing. Among these, hot bending is one of the most critical processes in 3D glass manufacturing and also the most challenging. Existing technologies generally adopt a process route of fine carving followed by hot bending, which involves first machining the outline, holes, and chamfers of the flat glass substrate using a CNC fine carving machine, and then placing it into a graphite mold for hot bending.

[0004] However, during the hot bending process described above, the glass deforms under the pressure of the mold while softened at high temperature. Uncontrollable shrinkage or expansion of the glass edges, especially at corners, can easily occur, causing the outline processed in the fine carving stage to shift after hot bending. As a result, the dimensional accuracy of the final product cannot meet high standards. Even if a probe positioning method is used to perform secondary fine carving and correction on the curved glass after hot bending, the positioning reference deviation problem remains prominent due to the uncertainty of the deformation of the curved glass. Furthermore, during hot bending, the uneven material flow in the four corners of the glass prevents the effective release of internal stress, which can easily lead to defects such as fold marks, microcracks, or deformation, affecting the appearance yield and structural strength of the product. Therefore, there is an urgent need to improve the technology of 3D curved glass cover processing structure to perfect this equipment. Summary of the Invention

[0005] The purpose of this invention is to provide a 3D curved glass cover processing technology based on precision carving pretreatment and hot bending forming, so as to solve the problems in the current market mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a 3D curved glass cover plate processing technology based on precision carving pretreatment and hot bending forming, characterized by comprising the following steps: S1 provides a flat glass substrate: a flat glass of uniform thickness is selected as the initial substrate, and the glass surface is cleaned and dried to ensure that the surface is free of contaminants; S2 Precision Engraving Pre-processing: The flat glass substrate is clamped on the working platform of the CNC engraving machine. The glass substrate has a bending area and a non-bending area. The non-bending area refers to the area of ​​the glass substrate that remains flat or has a small degree of bending after being hot-bent. Positioning marks, i.e. positioning holes, are made in the non-bending area of ​​the glass substrate through precision engraving. At the same time, the rough processing of the outer contour of the glass substrate or the pre-processing of the hole position are completed. S3 Grinding and Cleaning: The glass substrate after fine carving pretreatment is ground at the edges to remove burrs and micro-cracks generated during fine carving. Then, ultrasonic cleaning is used to remove residual processing debris and contaminants from the glass surface. S4 Hot Bending Forming: The glass substrate that has been pre-carved is placed into the hot bending mold, and the mold containing the glass substrate is sent into the hot bending machine. Under a protective atmosphere, it is heated and pressurized according to the preset temperature and pressure curves to form the preset 3D curved surface shape of the glass substrate in the mold cavity. S5 Fine Carving and Finishing: After hot bending, the 3D curved glass establishes a processing coordinate system based on the positioning holes. The 3D curved glass is then finely processed by a CNC carving machine. The fine processing includes, but is not limited to, the refinement of the outline, the fine processing of the holes, and the fine processing of the edge chamfers. S6 Removal of Positioning Marks: After fine carving and finishing, the positioning holes on the glass substrate are removed by polishing or grinding to restore the glass surface to flatness; S7 Post-processing: The 3D curved glass, after being finely carved and processed, undergoes polishing, chemical strengthening, and surface decoration treatments to finally obtain the finished 3D curved glass cover.

[0007] Preferably, the positioning hole is formed by laser etching or chemical etching.

[0008] Preferably, the hot bending die is a combination structure of a punch and a die made of high-purity isostatic graphite material, and the punch and the die form a cavity inside.

[0009] Preferably, the four corners of the internal cavity of the die are provided with arc grooves.

[0010] Preferably, the hot bending forming process includes a preheating section, a forming section, and an annealing section. The temperature of the preheating section is controlled at 500-650℃, the temperature of the forming section is controlled at 700-800℃, and the temperature of the annealing section is reduced to room temperature in stages.

[0011] Preferably, the coordinate system is established with the geometric center of the positioning hole as the reference point.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention creates positioning marks, or positioning holes, in the non-bending area during the precision carving pretreatment stage before hot bending. After hot bending, these positioning marks are used as a reference for precision carving and finishing. This effectively avoids the positioning reference deviation problem caused by hot bending deformation, enabling the final product to meet high standard requirements for dimensional accuracy. It overcomes the technical problem of dimensional deviation caused by hot bending deformation in traditional processes. Moreover, the precision carving pretreatment is only completed in the non-bending area, without affecting the material integrity of the bending area. Combined with a hot bending mold with a circular arc groove structure, the internal stress at the four corners of the glass is effectively released during the hot bending process, avoiding fold marks and deformation defects, and significantly improving the product's appearance yield and structural strength.

[0013] This invention achieves synergistic optimization of the fine carving and hot bending processes. The fine carving pretreatment only completes the positioning mark production and rough machining, and the final dimension fine machining is arranged after the hot bending forming. This not only utilizes the high-precision machining capability of the fine carving process, but also avoids the impact of hot bending deformation on the fine carving accuracy. It achieves synergistic cooperation between the fine carving and hot bending processes, further improving the overall product yield. Moreover, the manufacturing process is simple, easy to operate, and suitable for mass production. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the processing flow of the 3D curved glass cover plate of the present invention; Figure 2 This is a schematic diagram of the three-dimensional structure of the concave mold of the present invention.

[0015] In the figure: 1. Glass substrate; 11. Bending area; 12. Non-bending area; 2. Positioning hole; 3. Die; 31. Cavity; 32. Circular groove. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0017] Please see Figures 1 to 2 This invention provides a technical solution: a 3D curved glass cover plate processing technology based on precision carving pretreatment and hot bending forming, characterized by including the following steps: S1 provides a flat glass substrate: a 0.55mm thick high aluminosilicate flat glass is selected as the initial substrate. The large glass is cut into sheets of a preset size using a cutting device. Then, an ultrasonic cleaner is used with a semi-aqueous cleaning agent to clean the glass sheets, removing surface oil and impurities. After cleaning, the sheets are dried for later use.

[0018] S2 Precision Engraving Pre-treatment: The cleaned and dried flat glass substrate 1 is clamped on the working platform of the CNC engraving machine.

[0019] The glass substrate 1 is divided into a bending region 11 and a non-bending region 12 for hot bending. The bending region 11 is the four-sided region of the glass substrate, and the non-bending region 12 is the central region of the glass substrate.

[0020] A positioning hole 2 is machined at each of the four corners of the non-bending area 12 as a positioning mark. The diameter of the positioning hole 2 is 0.5mm, and the positioning hole 2 is 2mm away from the edge of the non-bending area 12. The four positioning holes 2 are distributed at the four corners of the non-bending area 12 to facilitate X / Y direction positioning when establishing the fine carving coordinate system later. At the same time, the outer contour of the glass substrate 1 is rough machined by a CNC fine carving machine, leaving a margin of 0.15mm on each side for subsequent fine machining.

[0021] S3 Grinding and Cleaning: The glass substrate 1 that has completed the fine carving pretreatment is subjected to edge grinding treatment. A 600-grit abrasive wheel is used to remove the tool marks and micro-cracks generated during fine carving. After grinding, the glass substrate 1 is placed in an ultrasonic cleaner for cleaning. It is rinsed with tap water, cleaned with water-based cleaning agent, rinsed with pure water in sequence, and finally dehydrated and dried.

[0022] S4 Hot Bending Forming: The cleaned and dried glass substrate 1 is placed in the hot bending mold. In this embodiment, a hot bending mold made of high-purity isostatic graphite material is used, including a punch and a die 3. The die 3 has a cavity 31 that matches the preset 3D curved surface shape. The four corners of the cavity 31 are provided with arc grooves 32. The function of the arc grooves 32 is that when the four corners of the glass are squeezed during the hot bending process, excess material and stress can be released through the arc grooves 32, avoiding fold marks or deformation at the four corners.

[0023] The mold containing the glass substrate 1 is fed into the hot bending machine and hot bending is performed under a nitrogen protective atmosphere. The hot bending process parameters are as follows: the preheating section is heated to 600°C and held for 180 seconds, the forming section is heated to 750°C, the punch is subjected to a pressure of 100 kgf and held for 120 seconds, and the annealing section is cooled to room temperature in stages at a cooling rate of 5°C / min.

[0024] After hot bending is completed, the four sides of the glass substrate 1 are bent into a preset curved shape, while the middle area remains flat, forming a 3D curved glass semi-finished product.

[0025] S5 Fine Carving and Finishing: The 3D curved glass after hot bending is used as the reference to establish a fine carving coordinate system.

[0026] The specific method is as follows: the geometric center positions of the four positioning holes 2 are identified by the CCD vision system, and the origin and direction of the machining coordinate system are calculated. Since the positioning holes 2 are set in the non-bending area 12 that does not deform during the hot bending process, their relative positional relationship remains unchanged before and after the hot bending. The accuracy of the machining coordinate system established in this way is much higher than that of the traditional positioning method based on the arc edge.

[0027] Under the established coordinate system, the 3D curved glass is precision-machined using a CNC engraving machine, including: refining the outline to the final size, precision machining of the camera hole, and fine machining of the edge chamfers.

[0028] S6 Removal of positioning marks: After the fine carving and finishing process is completed, the four positioning holes 2 on the non-bending area 12 of the glass substrate are removed by the polishing process, so that the glass surface is restored to flatness and smoothness.

[0029] S7 Post-processing: The following steps are performed: Polishing: A nylon brush and polishing liquid are used to polish the curved parts of the 3D curved glass to achieve a mirror effect; Chemical strengthening: The glass is placed in potassium nitrate molten salt for ion exchange strengthening at a strengthening temperature of 420℃ for 4 hours; and Surface decoration: An ink layer is screen-printed on the non-visible area of ​​the concave surface of the glass to form the final product.

[0030] Please see Figures 1 to 2 The positioning hole 2 is formed by laser etching or chemical etching. The hot bending mold is a combination structure of punch and die 3 made of high-purity isostatic graphite material. Cavities 31 are formed inside the punch and die 3. Arc grooves 32 are opened at the four corners of the internal cavity 31 of the die 3.

[0031] Please see Figures 1 to 2 The hot bending forming process includes a preheating section, a forming section, and an annealing section. The temperature of the preheating section is controlled at 500-650℃, the temperature of the forming section is controlled at 700-800℃, and the temperature of the annealing section is reduced to room temperature in stages. The coordinate system is established with the geometric center of the positioning hole as the reference point.

[0032] The 3D curved glass cover processing technology provided by this invention can be widely used in the manufacturing of glass covers for electronic devices such as smartphones, tablets, smartwatches, automotive displays, and laptops, and has good industrial practical value and application prospects.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A 3D curved glass cover processing technology based on precision carving pretreatment and hot bending forming, characterized in that, Includes the following steps: S1 provides a flat glass substrate: a flat glass of uniform thickness is selected as the initial substrate, and the glass surface is cleaned and dried to ensure that the surface is free of contaminants; S2 Precision carving preprocessing: The flat glass substrate is clamped on the working platform of the CNC precision carving machine. The glass substrate (1) is provided with a bending area (11) and a non-bending area (12). The non-bending area (12) refers to the area where the glass substrate remains flat or has a small degree of bending after hot bending. Positioning marks, i.e. positioning holes (2), are made in the non-bending area (12) of the glass substrate through precision carving. At the same time, the rough processing of the outer contour of the glass substrate or the pre-processing of the hole position are completed. S3 Grinding and Cleaning: The glass substrate after fine carving pretreatment is ground at the edges to remove burrs and micro-cracks generated during fine carving. Then, ultrasonic cleaning is used to remove residual processing debris and contaminants from the glass surface. S4 Hot Bending Forming: The glass substrate that has been pre-carved is placed into the hot bending mold, and the mold containing the glass substrate is sent into the hot bending machine. Under a protective atmosphere, it is heated and pressurized according to the preset temperature and pressure curves to form the preset 3D curved surface shape of the glass substrate in the mold cavity. S5 Fine Carving and Finishing: The 3D curved glass after hot bending is used as the reference to establish a processing coordinate system. The 3D curved glass is then finely processed by a CNC carving machine. The fine processing includes, but is not limited to, the fine finishing of the outline, the fine finishing of the holes, and the fine finishing of the chamfered edges. S6 Remove positioning marks: After fine carving and finishing, remove the positioning holes (2) on the glass substrate by polishing or grinding to restore the glass surface to flatness; S7 Post-processing: The 3D curved glass, after being finely carved and processed, undergoes polishing, chemical strengthening, and surface decoration treatments to finally obtain the finished 3D curved glass cover.

2. The 3D curved glass cover processing technology based on precision carving pretreatment and hot bending forming according to claim 1, characterized in that: The positioning hole (2) is formed by laser etching or chemical etching.

3. The 3D curved glass cover processing technology based on precision carving pretreatment and hot bending forming according to claim 1, characterized in that: The hot bending die is a combination structure of a punch and a die (3) made of high-purity isostatic graphite material, and a cavity (31) is formed inside the punch and the die (3).

4. The 3D curved glass cover processing technology based on precision carving pretreatment and hot bending forming according to claim 3, characterized in that: The inner cavity (31) of the die (3) is provided with arc grooves (32) at the four corners.

5. The 3D curved glass cover processing technology based on precision carving pretreatment and hot bending forming according to claim 1, characterized in that: The hot bending forming process includes a preheating section, a forming section, and an annealing section. The temperature of the preheating section is controlled at 500-650℃, the temperature of the forming section is controlled at 700-800℃, and the temperature of the annealing section is reduced to room temperature in stages.

6. The 3D curved glass cover processing technology based on precision carving pretreatment and hot bending forming according to claim 1, characterized in that: The coordinate system is established with the geometric center of the positioning hole as the reference point.

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