Polishing-free process for glass with small curvature radius
Through the glass polishing-free process of small curvature radius glass, the secondary thermal bending molding process is used to solve the problem of unevenness of the surface of the automobile display glass, simplifying the production process, allowing etching AG processing, and improving appearance quality and production efficiency.
Patent Information
- Application Number
- CN202411750994.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-02
- Publication Date
- 2025-03-14
AI Technical Summary
The existing automobiles show that when the glass thickness is 1.1mm/1.3mm and the 3D curved surface bending radius is less than R50, the surface is prone to uneven surfaces, which requires additional polishing steps, and the traditional process is not suitable for glass products with etched AG coatings.
The glass without polishing process of small curvature radius is adopted, including the selection of glass raw materials of appropriate specifications, performing steps such as cutting, CNC precision processing, first hot bending molding, annealing, natural cooling, second hot bending molding, annealing and natural cooling. The glass surface is ensured to be flat through the secondary hot bending molding process to avoid polishing steps.
Through the secondary thermal bending forming process, the problem of unevenness on the glass surface is solved, the production process is simplified, and the etching AG processing is allowed on the glass surface, which improves the appearance quality and production efficiency of the product.
Smart Images
Figure CN119612936A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of automobile display glass, and in particular to a polishing-free process for glass with a small curvature radius. Background Art
[0002] Automotive display glass refers to special glass used in automotive dashboards, infotainment systems, rearview mirrors, windows and other parts. This type of glass usually needs to have multiple functions. In addition to basic light transmittance, it also needs to consider durability, scratch resistance, anti-reflection, UV resistance and other characteristics to ensure the safety, convenience and comfort of drivers and passengers. Automotive display glass is a very important component of modern cars. It not only affects the appearance design and user experience of the car, but also directly affects the safety and convenience of driving. With the development of automotive technology, automotive display glass will continue to develop towards higher functionality, stronger durability and better display effects.
[0003] At present, the existing automotive display glass processing technology mainly includes cutting, CNC processing, hot bending, polishing, strengthening and other steps. However, under the conditions of glass thickness of 1.1mm / 1.3mm and 3D curved surface bending radius <R50, the product is prone to uneven surface appearance problems, which require additional polishing steps to solve. The traditional processing method is generally to thin the thickness of the glass to obtain a smoother surface, but these processes have some limitations. First, it cannot be used for glass products with etched AG coating, because the etched coating may be damaged during the polishing process; secondly, this process requires the use of a customized niche polishing machine, which means that the equipment is more specific and costly, and is not suitable for large-scale production. Summary of the invention
[0004] The purpose of the present invention is to solve the shortcomings existing in the prior art, and a small curvature radius glass polishing-free process is proposed, which includes the following steps: S1, selecting glass raw materials of suitable specifications, and cutting the materials according to the design requirements; S2, using CNC precision processing technology to perform preliminary processing on the glass to ensure the accuracy of the shape; S3, placing the processed glass into a mold, performing the first hot bending, heating and forming, and then annealing, and then naturally cooling to room temperature through a cooling plate; S4, performing a second hot bending on the glass that has not been fully formed by the first hot bending, placing the product into the mold again, preheating and forming, and then annealing, and then naturally cooling to room temperature through a cooling plate; S5, performing subsequent processes such as strengthening, cutting, and punching on the glass that has completed hot bending.
[0005] As a further description of the above technical solution: in step S3, the heating temperature is 600°C to 650°C, and the heating is continued for 30 to 40 minutes.
[0006] As a further description of the above technical solution: in step S3, molding is performed when the temperature reaches 650°C to 660°C, and the molding time is 6 minutes.
[0007] As a further description of the above technical solution: in step S3, the product is annealed at about 550°C for 10 minutes.
[0008] As a further description of the above technical solution: in step S4, preheating is performed at 600°C to 630°C, and heating is continued for 30 to 40 minutes.
[0009] As a further description of the above technical solution: in step S4, the molding temperature is 630°C and the molding time is 6 minutes.
[0010] As a further description of the above technical solution: in step S4, an annealing treatment at 550°C is then performed for 10 minutes.
[0011] The above technical solution has the following advantages or beneficial effects:
[0012] 1. The present invention uses a secondary hot bending molding process to ensure that the glass surface has no uneven appearance problem, thereby avoiding the polishing step in the traditional process and simplifying the production process. The process allows etching AG treatment on the glass surface, which cannot be performed in the traditional process due to the need for polishing. The secondary hot bending ensures that the warping of the product is controlled within 0.3mm to meet the customer's requirements for appearance accuracy. The two hot bendings ensure that the glass is always heated evenly throughout the entire molding process, avoiding appearance defects caused by high temperature or uneven heating. Through process optimization, not only the appearance quality of the product is improved, but also the production links and operation difficulties are reduced, thereby improving the overall production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 The process flow chart of the small curvature radius glass polishing-free process of the present invention;
[0014] Figure 2 This is a temperature variation curve of the small curvature radius glass free polishing process of the present invention. DETAILED DESCRIPTION
[0015] 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.
[0016] like Figure 1-2As shown, a small curvature radius glass polishing-free process of the present invention includes the following steps: S1, selecting glass raw materials of appropriate specifications, and cutting the materials according to the design requirements; S2, using CNC precision processing technology to perform preliminary processing on the glass to ensure the accuracy of the shape; S3, placing the processed glass into a mold, performing the first hot bending, heating and forming, and then annealing, and then naturally cooling to room temperature through a cooling plate; S4, performing a second hot bending on the glass that was not fully formed by the first hot bending, placing the product into the mold again, preheating and forming, and then annealing, and then naturally cooling to room temperature through a cooling plate; S5, performing subsequent processes such as strengthening treatment, cutting, and punching on the glass that has completed hot bending.
[0017] In this embodiment, the glass raw material is placed in the mold and preheated at 600℃~650℃ for 30min~40min to make the glass material evenly heated and reach a state suitable for molding. When the temperature of the preheated glass material reaches about 650℃~660℃, molding begins, and the molding time is about 6 minutes. At this time, since the softening temperature of the glass is about 750℃, this temperature range can ensure that the glass is initially formed in the mold, and the shape is close to the final demand, but because the mold is not pressed, there will be no obvious unevenness on the surface. After molding, the glass product is annealed to about 550℃ and maintained for about 10 minutes to ensure that the material is gradually cooled to a suitable temperature to avoid the accumulation of internal stress and increase the flatness of the glass surface and edges. The annealed glass product is naturally cooled to room temperature through a cooling plate. In this process, the initial shape of the glass material is completed, but because the mold is not pressed, the product warpage is large, generally 0.6mm~0.8mm. At this time, there is no obvious unevenness on the surface, which meets the appearance requirements. The glass product formed for the first time is put into the mold again, and preheated at 600℃~630℃ again for 30min~40min to ensure that the glass material is evenly heated to the appropriate temperature. When preheated to about 630℃, the second molding is carried out for about 6 minutes. At this time, due to the low temperature, the softening degree of the glass is moderate, and the shape of the glass product will be further fine-tuned. At this time, the temperature is low, which can avoid the uneven surface appearance caused by excessive temperature and mold pressing. After the second molding is completed, the glass product is annealed again to 550℃ for about 10 minutes to ensure that the glass material is fully cooled and further relieve the internal stress. It is naturally cooled to room temperature through the cooling plate. In this process, the glass product undergoes secondary expansion and contraction, the shape is fully adjusted, and the warpage can be controlled within 0.3mm, meeting the customer's precision requirements. After two rounds of hot bending and sufficient annealing, the warping of the glass product is controlled within 0.3mm. The product surface is flat without obvious bumps and defects, which meets the customer's high-quality requirements for the shape and appearance of glass products. It can effectively avoid appearance defects and reduce the polishing process. At the same time, it can support etching AG processing, which has significant technical advantages and market value.
[0018] Among them, through the secondary hot bending molding process, the glass surface has no uneven appearance problems, thus avoiding the polishing steps in the traditional process and simplifying the production process. This process allows etching AG treatment on the glass surface, which cannot be performed in the traditional process due to the need for polishing. AG treatment can effectively reduce the reflection of the glass surface and improve the display effect. Through the secondary hot bending, the warping of the product is controlled within 0.3mm to meet the customer's requirements for appearance accuracy. The use of two hot bendings ensures that the glass is always heated evenly throughout the entire molding process, avoiding appearance defects caused by high temperature or uneven heating. Through process optimization, not only the appearance quality of the product is improved, but also the production links and operation difficulties are reduced, and the overall production efficiency is improved.
[0019] Specifically, the traditional process flow: cutting---CNC---hot bending---polishing---strengthening---post-process is improved to cutting---CNC---first hot bending---second hot bending---strengthening---post-process. By optimizing the process steps, the disadvantages of traditional processes in glass product processing are overcome, especially for glass products with a thickness of 1.1mm / 1.3mm and a 3D curved surface bending radius of <R50. It can effectively avoid appearance defects and reduce the polishing process. At the same time, it can support etching AG processing, which has significant technical advantages and market value.
[0020] like Figure 2 As shown, in step S3, the heating temperature is 600°C to 650°C, and the heating is continued for 30 to 40 minutes; the glass becomes soft and plastic enough when heated to a temperature range of 600°C to 650°C. This temperature range changes the molecular structure of the glass, which can smoothly adapt to the curved shape of the mold in the subsequent molding process. If the temperature is too low, the glass cannot be fully softened, resulting in difficulty in molding; if the temperature is too high, the glass surface may be damaged or defects such as bubbles and cracks may be generated. The purpose of continuous heating for 30 to 40 minutes is to ensure that the glass can be fully heated evenly at this temperature, and the entire glass thickness can reach the required temperature. During this period of time, the heat inside the glass is evenly conducted to ensure that the temperature of the glass surface and the inside is consistent, avoiding uneven glass surface or inconsistent deformation due to uneven heat distribution.
[0021] like Figure 2 As shown, in step S3, the molding is performed when the temperature reaches 650°C to 660°C, and the molding time is 6 minutes; within the temperature range of 650°C to 660°C, the glass has reached an ideal plastic state. At this time, the molecular structure of the glass becomes looser and can be deformed flexibly in the molding mold, avoiding the glass being too hard and difficult to shape due to insufficient temperature. However, too high a temperature may cause damage to the glass surface or generate too much internal stress, so the temperature range of 650°C to 660°C is particularly critical for glass molding.
[0022] like Figure 2 As shown, in step S3, the product is annealed at about 550°C for 10 minutes; the main purpose is to eliminate the internal stress that may be generated in the glass during hot bending or heating, and ensure the structural stability of the glass. During the heating and cooling process, the glass may generate internal stress due to temperature gradient or uneven heating. The annealing process can fully adjust the molecular structure of the glass through slow and uniform heating, thereby eliminating these internal stresses and avoiding the glass from breaking or warping due to stress concentration during the cooling process. If the glass has tiny surface cracks or uneven stress distribution during the molding process, the annealing treatment can help repair these surface defects. The annealing temperature of about 550°C does not remelt the glass, but is in a temperature range that allows the glass to self-adjust at the molecular level, reduce surface stress, and thus reduce the risk of breakage. The purpose of annealing at 550°C for 10 minutes is to eliminate the stress inside the glass through appropriate heating time and temperature, ensure its stability and uniformity, avoid stress concentration problems during the molding process, and improve the strength and reliability of the final product.
[0023] like Figure 2 As shown, in step S4, the preheating is performed at 600°C to 630°C for 30 to 40 minutes; the core function of the preheating process is to ensure the uniform temperature distribution of the glass during the heating process. When the glass is heated, a temperature gradient may be generated due to its own thickness and material. By heating the glass to 600°C to 630°C and maintaining it for a certain period of time, it can be ensured that the temperature of the surface and the inside of the glass are close, thereby avoiding internal stress or local deformation due to excessive temperature difference. When the glass is heated to a temperature range of 600°C to 630°C, its thermal expansion characteristics begin to stabilize. This temperature range can not only avoid the softening or deformation of the glass caused by excessively high temperatures, but also prepare for subsequent higher temperature heating processes. The expansion coefficient of the glass is relatively stable within this temperature range, helping to keep the shape and size of the glass from changing suddenly.
[0024] like Figure 2As shown, in step S4, the molding temperature is 630°C and the molding time is 6 minutes; at a temperature of 630°C, the viscosity of the glass decreases, becoming softer and easier to mold. This temperature changes the glass from a hard and brittle state to a state of higher plasticity. Therefore, the setting of the molding temperature is crucial to the processability and molding accuracy of the glass. At this temperature, the glass can more easily adapt to the shape of the mold, avoiding molding difficulties or defects caused by too high or too low temperatures. By maintaining a heating time of 6 minutes at 630°C, the glass will be evenly heated and shaped during this process, ensuring that the fluidity and viscosity of the glass are consistent, so that the molding accuracy and uniformity can be guaranteed. Especially when producing glass products with complex shapes, uniform heating helps to avoid surface defects and shape distortion.
[0025] like Figure 2 As shown, in step S4, an annealing treatment at 550°C is then performed for 10 minutes; internal stress may be generated in the glass during the molding process, especially after rapid heating or rapid cooling, stress concentration may exist inside the glass. The annealing temperature of 550°C is between the softening point and the hardening point of the glass, which can effectively relieve the internal stress in the glass. Through the annealing treatment, the molecular structure of the glass will be fine-tuned, reducing the internal stress caused by uneven cooling or heating, thereby improving the overall stability and strength of the glass.
[0026] Specifically, in the glass bending process, each temperature range and time setting has a specific purpose, which is to achieve uniform heating, control the plasticity of the glass, avoid surface defects, and ensure that the warpage and appearance of the final product meet customer needs. The following is an analysis of the reasons and functions of each temperature range and time setting:
[0027] 1. Preheating range of 600℃~650℃ (lasting 30 minutes~40 minutes)
[0028] Function: Uniform heating: The temperature distribution of glass must be uniform during heating. If the temperature is too low, the glass cannot be fully softened, resulting in poor molding; if the temperature is too high, the glass surface will soften too quickly, affecting the surface quality. The preheating temperature of 600℃~650℃ can gradually heat the glass to a plastic state, avoid thermal stress concentration, and ensure the overall uniformity of the glass during molding.
[0029] Reduce thermal stress: When heating the glass, temperature differences may cause excessive internal stress in the glass, so the temperature needs to be increased gradually to avoid cracking or deformation of the glass due to excessive temperature differences.
[0030] Prepare for subsequent molding: In this range, the glass is preheated to close to its softening temperature (750°C), which enables the glass to have sufficient plasticity in the subsequent high-temperature molding process and facilitate deformation in the mold.
[0031] 2.650℃~660℃ molding range (lasting 6 minutes)
[0032] Function: To achieve glass molding: In this temperature range, the plasticity of glass reaches the best state. Since the softening point of glass is about 750℃, the temperature range of 650℃~660℃ enables the glass to maintain sufficient softening while avoiding excessive softening, so that it can be effectively molded.
[0033] Avoid excessive deformation: At this time, the glass surface will not produce uneven surface defects due to direct contact with the mold at high temperature. At the same time, the plasticity of the glass is sufficient to ensure that it can adapt to the shape of the mold and complete the molding.
[0034] 3.550℃ annealing zone (lasting 10 minutes)
[0035] Function: Eliminate thermal stress: There may be a temperature difference between the surface and the inside of the formed glass, which will cause thermal stress inside the glass. If annealing is not performed, these stresses may cause cracks or deformation in the glass. The annealing process helps to relieve and release these stresses and ensure the stability of the glass shape.
[0036] Stable structure: The annealing process cools the glass slowly and reduces the temperature difference during the cooling process, so that the glass maintains a stable structure during the cooling process and avoids cracks after cooling.
[0037] 4. Cool to room temperature (natural cooling through cooling plate)
[0038] Function: Slow cooling, avoid rapid cooling: Rapid cooling will cause uneven thermal stress in the glass, which may cause cracking or uneven deformation. Natural cooling through the cooling plate gradually reduces the temperature of the glass, which helps to keep its shape stable and avoid cracks caused by thermal shock.
[0039] Avoid surface defects: Natural cooling can also avoid surface unevenness or bumps caused by rapid cooling, ensuring the surface quality of the glass.
[0040] 5. Second preheating (600℃~630℃, lasting 30 minutes~40 minutes)
[0041] Function: Ensure that the glass softens again: Since the glass has only completed about 90% of its forming during the first hot bending process, and the warping is between 0.6mm and 0.8mm, it is necessary to heat the glass a second time to make it reach the best plastic state and help the glass to be further adjusted and formed in the mold.
[0042] Uniform heating: The second preheating is to ensure that the temperature of the glass is evenly distributed before it is formed, reducing any stress and deformation caused by temperature differences.
[0043] 6.630℃ molding zone (lasting 6 minutes)
[0044] Function: Re-molding and adjustment: After the first molding, the shape of the glass may have some deviation (excessive warpage). At this time, it is heated to 630℃, and the glass has become softer and can better adapt to the shape of the mold to complete the remaining molding tasks. The temperature is set lower to avoid additional surface defects at high temperatures.
[0045] Fine-tune the shape: Through the second forming, the glass can be further bent and adjusted to ensure that the places that were not fully bent into place during the first forming are fully adjusted.
[0046] 7.550℃ annealing zone (lasting 10 minutes)
[0047] Function: Eliminate new internal stress: After the second molding, the temperature difference inside the glass may cause stress accumulation again, so it is necessary to release these stresses through annealing again to ensure that the glass does not deform or break during the cooling process.
[0048] Ensure shape stability: After annealing, the shape of the glass is more stable and the internal stress distribution is more uniform, avoiding deformation during the subsequent cooling process.
[0049] 8. Cool to room temperature (natural cooling through cooling plate)
[0050] Function: Ensure final stability: After two molding and annealing processes, the glass needs to be naturally cooled to stabilize its final shape. Slow cooling can further reduce the stress in the glass and ensure that its shape does not change.
[0051] Smooth surface: Through natural cooling, the glass surface will not have problems such as unevenness or cracks due to excessive cooling, ensuring that the final product has a smooth and intact appearance.
[0052] Through two rounds of forming and annealing, combined with precise temperature control and time settings, it is possible to ensure that the glass is gradually adjusted and perfected in shape during the hot bending process, ultimately meeting the customer's strict requirements for warpage (within 0.3mm). The processing at each stage plays a role in reducing stress, adjusting the shape, and avoiding surface defects, thereby ensuring that the final product not only meets the precision requirements, but also has a high-quality surface and stability.
[0053] Working principle: Through the secondary hot bending process, the staff makes the glass surface have no uneven appearance problems, thus avoiding the polishing steps in the traditional process and simplifying the production process. This process allows etching AG treatment on the glass surface, which cannot be performed due to the need for polishing. Through secondary hot bending, the warping of the product is controlled within 0.3mm to meet the customer's requirements for appearance accuracy. The use of two hot bending processes ensures that the glass is always evenly heated throughout the entire molding process, avoiding appearance defects caused by high temperature or uneven heating. Through process optimization, not only the appearance quality of the product is improved, but also the production links and operation difficulties are reduced, thereby improving the overall production efficiency.
[0054] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A small curvature radius glass free polishing process, characterized in that: The steps include: S1. Select glass raw materials of appropriate specifications and cut them according to design requirements; S2. Use CNC precision processing technology to perform preliminary processing on the glass to ensure the accuracy of the shape; S3, the processed glass is placed in a mold, subjected to the first heat bending, heated and formed, then annealed, and then naturally cooled to room temperature on a cooling plate; S4, performing a second hot bending on the glass that was not fully formed after the first hot bending, placing the product into the mold again, performing preheating and forming, then performing annealing treatment, and then naturally cooling to room temperature through a cooling plate; S5. Perform subsequent processes such as strengthening, cutting, and punching on the hot-bent glass.
2. The small curvature radius glass free polishing process according to claim 1, characterized in that: In step S3 , the heating temperature is 600° C. to 650° C., and the heating is continued for 30 to 40 minutes.
3. The small curvature radius glass free polishing process according to claim 1, characterized in that: In step S3, molding is performed when the temperature reaches 650°C to 660°C, and the molding time is 6 minutes.
4. The small curvature radius glass free polishing process according to claim 1, characterized in that: In step S3, the product is annealed at about 550°C for 10 minutes.
5. The small curvature radius glass free polishing process according to claim 1, characterized in that: In step S4, preheating is performed at 600° C. to 630° C. and the heating is continued for 30 to 40 minutes.
6. The small curvature radius glass free polishing process according to claim 1, characterized in that: In step S4, the molding temperature is 630° C. and the molding time is 6 minutes.
7. The small curvature radius glass free polishing process according to claim 1, characterized in that: In step S4, an annealing treatment is then performed at 550°C for 10 minutes.