3D glass hot bending forming process

Abstract

The invention provides a 3D glass hot bending forming technology, and relates to the technical field of 3D glass preparation, and the 3D glass hot bending forming technology comprises the following steps: 1, designing and cutting plate glass according to 3D glass, and carrying out CNC finish machining, washing and drying to obtain plate original glass; step 2, loading the dried plate original glass into a mold, and preheating the plate original glass step by step in a multi-stage preheating station; 3, after the preheated and heated mold is moved to a hot pressing station, 3D glass in a preset shape is obtained by adjusting the temperature of an upper pressing plate and a lower pressing plate and adjusting the pressing speed and the load of the upper pressing plate; 4, the hot-pressed 3D glass mold is moved to annealing stations, and the minimum resilience effect of the 3D glass is achieved through step-by-step cooling of the multi-stage annealing stations; and step 5, taking out the 3D glass, cooling, cleaning, laminating, and finishing. The method is used for solving the technical problems that a traditional 3D glass hot bending process is difficult to meet the specification requirement that the size precision of a product is lower than 0.2 mm, and concave and convex points exist on the surface of the glass, and further grinding and polishing are needed.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of 3D glass preparation, and in particular to a 3D glass hot bending forming process. Background Art

[0002] 3D glass not only has the characteristics of transparency, sun resistance, small deformation and strong reliability, but also can be designed with unique curvature characteristics according to the needs of the usage occasion. It is widely used in mobile phones, smart watches, vehicle display cover plates, HUD head-up displays and other fields.

[0003] However, when the glass size exceeds 15 inches, the thermal bending deformation of the center and edge areas of the product is not synchronized, which affects the overall deformation consistency of the glass. The traditional 3D glass thermal bending process is difficult to achieve product size accuracy below 0.2mm specification requirements. The thermal bending deformation of the center and edge areas of the product is not synchronized. This phenomenon is mainly caused by the real-time temperature difference between the edge and center areas. Specifically, the edge area rises and cools down before the center area. The real-time temperature difference phenomenon will also cause stress concentration and cooling rebound problems, further aggravating the dimensional deviation of 3D glass.

[0004] In addition, the traditional 3D glass bending process easily creates uneven spots on the product surface, which requires a polishing process for post-processing, increasing the difficulty of preparation and manufacturing costs, greatly limiting the development of the 3D glass industry. How to control the product precision while ensuring its good appearance, thereby eliminating the polishing process, has been a problem that has plagued a large number of practitioners.

[0005] It should be noted that the above contents belong to the technical cognition scope of the inventor. Since the technical contents in this field are vast and too complicated, the above contents of this application do not necessarily constitute prior art. Summary of the invention

[0006] 1. Technical problems to be solved by the invention: The present invention provides a 3D glass hot bending forming process to solve the technical problems existing in the above-mentioned background technology.

[0007] 2. Technical solution: To achieve the above object, the present invention provides a technical solution: a 3D glass hot bending forming process, comprising the following steps: Step 1: Prepare the flat glass, design and cut the flat glass according to the 3D glass, and then obtain the flat glass through CNC finishing, washing and drying; Step 2: Load the dried flat glass into the mold and preheat it step by step in the multi-stage preheating station; Step 3: After the preheated mold is moved to the hot pressing station, the 3D glass of the preset shape is obtained by adjusting the temperature of the upper and lower pressing plates and the pressing speed and load of the upper pressing plate; Step 4: The 3D glass mold after hot pressing is moved to the annealing station, and the temperature is gradually reduced in the multi-stage annealing station to achieve the minimum rebound effect of the 3D glass; Step 5: Take out the 3D glass and cool, clean and coat it to complete the 3D glass hot bending process.

[0008] Furthermore, in step 2, the number of multi-stage preheating stations i≥4, and the temperatures of different preheating stations are increased step by step.

[0009] Furthermore, in step 2, the preset temperature of the first multi-stage preheating station is 300-500°C, and the preset temperature of the i-th stage preheating station is not more than 700°C.

[0010] Furthermore, in step 2, the multi-stage preheating station is divided into an upper heat source and a lower heat source, the upper heat source adopts a near-infrared radiation heating method, and the lower heat source adopts a resistance wire heat conduction or a near-infrared radiation heating method.

[0011] Furthermore, in step three, the pressing speed of the upper pressing plate of the hot pressing station is 0.2~2mm / s, the pressing force of the hot pressing station is 0.05~1.5MPa, and after the hot pressing station is fully pressed, the holding time is 10~60s.

[0012] Furthermore, in step 4, the number of multi-stage annealing stations j≥3, and the preset temperatures of different annealing stations decrease step by step.

[0013] Furthermore, in step 4, the upper and lower heat sources of the multi-stage annealing station both use a heating method of resistance wire heat conduction, the upper pressing plate and the lower bottom plate have the same temperature, and after entering the annealing station, the upper pressing plate is always pressed on the upper mold.

[0014] Furthermore, in step 4, the first multi-stage annealing station is preset at a temperature of 500-600°C, and the j-th stage annealing station is preset at a temperature of 300°C.

[0015] Furthermore, in step 2, step 3 and step 4, the multi-stage preheating station, hot pressing station and multi-stage annealing station are all equipped with temperature measuring thermocouples, and the heating and cooling time of the mold in the multi-stage preheating station, hot pressing station and multi-stage annealing station can be set individually.

[0016] Furthermore, in step 2, step 3, and step 4, the mold punch is set as an upper mold, and the mold concave is set as a lower mold.

[0017] Furthermore, the upper mold and the lower mold of the mold are pushed into the multi-stage preheating station by different transmission mechanisms respectively, and the upper mold is suspended by a hanger. A distance is maintained between the upper mold and the lower mold, and the distance can be adjusted by the hanger.

[0018] 3. Beneficial effects: Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: The present invention is reasonably designed, and adopts a multi-stage preheating and annealing scheme to improve the consistency of the overall temperature of the glass and suppress the occurrence of stress concentration; through a rapid pressing scheme, the contact time between the glass and the mold in the high temperature zone is reduced, and the appearance abnormality is reduced; a pressure-holding segmented annealing scheme is adopted, relying on step cooling and continuous pressure holding to control the temperature difference of the glass in each area during the cooling process and suppress the rebound phenomenon; a rapid cooling scheme is adopted to make the mold approach room temperature before leaving the furnace, reducing mold oxidation. The 3D glass hot bending molding process described in the present invention has high product precision, simple operation, and no need for polishing, which greatly reduces production costs; Compared with the traditional 3D glass hot bending process, the 3D glass hot bending molding process described in the present invention has low cost, high efficiency, simple operation, stable product dimensional accuracy within 0.2mm, and good appearance without polishing.

[0019] It should be noted that the structures not introduced in the present invention are the same as the prior art or can be implemented by using the prior art, and are not described in detail here because they do not involve the design points and improvement directions of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION

[0021] To facilitate understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0022] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "page", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0023] 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. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0024] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed", "provided with", "provided on" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] The embodiment of the present invention introduces a 3D glass hot bending forming process, which includes the following steps: Step 1: Prepare the flat glass, design and cut the flat glass according to the 3D glass, and then obtain the flat glass through CNC finishing, washing and drying; Step 2: Load the dried flat glass into the mold and preheat it step by step in the multi-stage preheating station; Step 3: After the preheated mold is moved to the hot pressing station, the 3D glass of the preset shape is obtained by adjusting the temperature of the upper and lower pressing plates and the pressing speed and load of the upper pressing plate; Step 4: The 3D glass mold after hot pressing is moved to the annealing station, and the temperature is gradually reduced in the multi-stage annealing station to achieve the minimum rebound effect of the 3D glass; Step 5: Take out the 3D glass and cool, clean and coat it to complete the 3D glass hot bending process.

[0026] In step 2, the number of multi-stage preheating stations i ≥ 4, and the temperatures of different preheating stations increase step by step.

[0027] In step 2, the preset temperature of the first multi-stage preheating station is 300-500°C, the preset temperature of the i-th stage preheating station does not exceed 700°C, and the rising temperature of the latter stage preheating station is lower than the rising temperature of the previous stage preheating station.

[0028] In step 2, the multi-stage preheating station is divided into an upper heat source and a lower heat source. The upper heat source adopts a near-infrared radiation heating method, and the lower heat source adopts a resistance wire heat conduction or a near-infrared radiation heating method. By using near-infrared radiation as the upper heat source for heating the flat plate original glass, the heating uniformity of the flat plate original glass is increased.

[0029] In step three, the pressing speed of the upper pressing plate of the hot pressing station is 0.2~2mm / s, the pressing force of the hot pressing station is 0.05~1.5MPa, and after the hot pressing station is fully pressed, the holding time is 10~60s.

[0030] In step 4, the number of multi-stage annealing stations j≥3, and the preset temperatures of different annealing stations decrease step by step.

[0031] In step 4, the upper and lower heat sources of the multi-stage annealing station both use resistance wire heat conduction to increase the temperature, the upper pressing plate and the lower bottom plate have the same temperature, and after entering the annealing station, the upper pressing plate is always pressed on the upper mold.

[0032] In step 4, the first multi-stage annealing station is preset at a temperature of 500-600°C, and the j-stage annealing station is preset at a temperature of 300°C.

[0033] In step 2, step 3 and step 4, the multi-stage preheating station, hot pressing station and multi-stage annealing station are all equipped with temperature measuring thermocouples for real-time monitoring of relevant temperature parameters. The heating and cooling time of the mold in the multi-stage preheating station, hot pressing station and multi-stage annealing station can be set individually. Since the preheating, hot pressing and annealing conditions of 3D glass with different specifications and shapes are different, setting the time individually according to the situation can improve the final forming effect of the 3D glass.

[0034] In step 2, step 3 and step 4, the punch of the mold is set as the upper mold, and the concave mold is set as the lower mold. The upper mold and the lower mold can be used even if they are installed in reverse positions.

[0035] In addition, it should be noted that the upper mold and the lower mold of the mold are pushed into the multi-stage preheating station by different transmission mechanisms respectively, and the upper mold is suspended by a hanging rack. A distance is maintained between the upper mold and the lower mold, and the distance can be adjusted by the hanging rack to avoid the flat glass being subjected to the pressure of the upper mold in the early softening stage, which may cause the glass surface accuracy to decrease, and reduce the appearance defects caused by direct contact between the upper mold and the flat glass.

[0036] The following is the implementation of the operation in combination with the specific process flow; Example 1

[0037] A 3D vehicle glass cover plate hot bending forming process comprises the following steps: Step 1: Design and cut the flat glass according to the 3D glass, and then obtain the flat original glass through CNC finishing, washing and drying; Step 2: Load the dried flat glass into the mold, heat it to 400°C in the first preheating station, 500°C in the second preheating station, 570°C in the third preheating station, and 600°C in the fourth preheating station; Step 3: Move the mold to the hot press station, adjust the temperature of the upper press plate to 620°C and the temperature of the lower press plate to 600°C, adjust the descending speed of the upper press plate to 1mm / s, and adjust the load to 0.1MPa. After holding the pressure for 30S, the upper press plate is depressurized; Step 4: The mold moves to the annealing station, and the temperature is lowered to 560°C in the first annealing station, 530°C in the second annealing station, 500°C in the third annealing station, and 400°C in the fourth annealing station. During this process, the upper and lower platens have the same temperature, the upper platen descends at a speed of 1mm / s, and the load is adjusted to 0.1MPa. The pressure is maintained throughout the process until the mold leaves. Step 5: Take out the 3D glass and cool, clean and coat it to complete the 3D glass hot bending process. Example 2

[0038] Step 1: Design and cut the flat glass according to the 3D glass, and then obtain the flat original glass through CNC finishing, washing and drying; Step 2: Load the dried flat glass into the mold. The heating time of the mold in the first preheating station is 600s, and the mold temperature rises from the initial temperature of 200℃ to 400℃, with a heating rate of 20℃ / min; the heating time of the second preheating station is 400s, and the mold heating rate is 15℃ / min; the heating time of the third preheating station is 400s, and the mold heating rate is 7.5℃ / min; the heating time of the fourth preheating station is 600s, and the mold heating rate is 5℃ / min; Step 3: The mold is moved from the preheating station to the hot pressing station. The mold is heated up for 240 seconds in the hot pressing station at a rate of 5°C / min. After the pressure holding is completed, the upper pressing plate is depressurized, the upper mold is separated from the rack, and is supported by the lower mold and the glass. Step 4: The mold is moved from the hot pressing station to the annealing station. The cooling time of the mold in the first-level annealing station is 1000s, the mold temperature drops from 600℃ to 560℃, and the annealing rate is 2.5℃ / min; the cooling time of the mold in the second and third-level annealing stations is 600s, and the annealing rate is 3℃ / min; the cooling time of the mold in the fourth-level annealing station is 1200s, and the annealing rate is 5℃ / min; Step 5: The mold is moved from the annealing station to the cooling station and air-cooled to 200°C. The 3D glass is taken out from the feeding station and cooled, cleaned, and coated to complete the 3D glass hot bending process.

[0039] The above-described embodiments only express a certain implementation mode of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A 3D glass hot bending forming process, characterized in that: The following steps are included Step 1: Prepare the flat glass, design and cut the flat glass according to the 3D glass, and then obtain the flat glass through CNC finishing, washing and drying; Step 2: Load the dried flat glass into the mold and preheat it step by step in the multi-stage preheating station; Step 3: After the preheated mold is moved to the hot pressing station, the 3D glass of the preset shape is obtained by adjusting the temperature of the upper and lower pressing plates and the pressing speed and load of the upper pressing plate; Step 4: The 3D glass mold after hot pressing is moved to the annealing station, and the temperature is gradually reduced in the multi-stage annealing station to achieve the minimum rebound effect of the 3D glass; Step 5: Take out the 3D glass and cool, clean and coat it to complete the 3D glass hot bending process.

2. A 3D glass hot bending forming process according to claim 1, characterized in that: In step 2, the number of multi-stage preheating stations i ≥ 4, and the temperatures of different preheating stations increase step by step.

3. A 3D glass hot bending forming process according to claim 2, characterized in that: In step 2, the preset temperature of the first multi-stage preheating station is 300-500°C, and the preset temperature of the i-th stage preheating station is not more than 700°C.

4. A 3D glass hot bending forming process according to claim 1, characterized in that: In step 2, the multi-stage preheating station is divided into an upper heat source and a lower heat source. The upper heat source adopts a near-infrared radiation heating method, and the lower heat source adopts a resistance wire heat conduction or a near-infrared radiation heating method.

5. The 3D glass hot bending forming process according to claim 1, characterized in that: In step three, the pressing speed of the upper pressing plate of the hot pressing station is 0.2~2mm / s, the pressing force of the hot pressing station is 0.05~1.5MPa, and after the hot pressing station is fully pressed, the holding time is 10~60s.

6. A 3D glass hot bending forming process according to claim 1, characterized in that: In step 4, the number of multi-stage annealing stations j≥3, and the preset temperatures of different annealing stations decrease step by step.

7. The 3D glass hot bending forming process according to claim 1, characterized in that: In step 4, the upper and lower heat sources of the multi-stage annealing station both use resistance wire heat conduction to increase the temperature, the upper pressing plate and the lower bottom plate have the same temperature, and after entering the annealing station, the upper pressing plate is always pressed on the upper mold.

8. The 3D glass hot bending forming process according to claim 6, characterized in that: In step 4, the first multi-stage annealing station is preset at a temperature of 500-600°C, and the j-stage annealing station is preset at a temperature of 300°C.

9. The 3D glass hot bending forming process according to claim 1, characterized in that: In step 2, step 3 and step 4, the multi-stage preheating station, hot pressing station and multi-stage annealing station are all equipped with temperature measuring thermocouples, and the heating and cooling time of the mold in the multi-stage preheating station, hot pressing station and multi-stage annealing station can be set separately; In step 2, step 3 and step 4, the punch of the mold is set as an upper mold and the concave mold is set as a lower mold.

10. A 3D glass hot bending forming process according to claim 9, characterized in that: The upper die and the lower die of the mold are pushed into the multi-stage preheating station by different transmission mechanisms respectively, the upper die is suspended by a hanging rack, and a distance is maintained between the upper die and the lower die, and the distance is adjusted by the hanging rack.

Images