阅读说明：本技术 非等厚曲面玻璃净成型工艺、模具、预制件及其设计方法 (Non-uniform-thickness curved glass net forming process, mold, prefabricated part and design method thereof ) 是由 潘再勇 王健强 王乃帅 于 2021-10-12 设计创作，主要内容包括：本发明属于玻璃加工技术领域,具体公开了一种非等厚曲面玻璃净成型工艺、模具、预制件及其设计方法,旨在提高制作非等厚曲面玻璃元件过程中对材料的利用率并降低加工成本。本发明提供的成型模具通过其成型腔,能够将软化的预制件成型为需要的非等厚曲面玻璃；其能够用于精密净成型工艺,配合精确设计的预制件,一次性制作成型非等厚曲面玻璃,提高了制作非等厚曲面玻璃过程中对材料的利用率、以及加工效率和良品率,并降低加工成本。本发明提供的成型工艺采用上述的成型模具和设计的预制件制作非等厚曲面玻璃,制作过程中通过除氧并有效控制成型工艺参数,不仅能够实现净成型并使得玻璃充型饱满,而且能够提高制作的非等厚曲面玻璃的表面质量。(The invention belongs to the technical field of glass processing, and particularly discloses a non-uniform-thickness curved glass net forming process, a mold, a prefabricated member and a design method thereof, aiming at improving the utilization rate of materials in the process of manufacturing non-uniform-thickness curved glass elements and reducing the processing cost. The forming mold provided by the invention can form the softened prefabricated member into the required non-uniform-thickness curved glass through the forming cavity of the forming mold; the method can be used for a precise net forming process, and matched with a precisely designed prefabricated part, the non-uniform-thickness curved glass can be manufactured and formed at one time, so that the utilization rate of materials, the processing efficiency and the yield of the non-uniform-thickness curved glass are improved, and the processing cost is reduced. The forming process provided by the invention adopts the forming mold and the designed prefabricated member to manufacture the non-uniform-thickness curved glass, and not only can realize net forming and make the glass fully filled, but also can improve the surface quality of the manufactured non-uniform-thickness curved glass by removing oxygen and effectively controlling the forming process parameters in the manufacturing process.)

1. The non-uniform thickness curved surface glass net forming die is characterized in that: comprises a convex die (100), a concave die (200), an inner die sleeve (300) and an outer die sleeve (400);

the lower part of the convex die (100) is provided with a bulge (110), the bulge (110) comprises a connecting part and a profiling part arranged on the lower side of the connecting part, the profiling part comprises a profiling surface (111), the profiling surface (111) comprises a middle plane and two convex arc surfaces respectively arranged at the left end and the right end of the middle plane, and the convex arc surfaces are in smooth transition connection with the middle plane;

the upper part of the concave die (200) is provided with a groove (210), the groove (210) comprises a notch matched with the connecting part of the bulge (110) and a forming part arranged on the lower side of the notch, and the forming part comprises a forming surface (211) corresponding to the middle plane of the pressing surface (111) and two concave arc surfaces respectively arranged at the left end and the right end of the forming surface (211);

when the forming die is closed, the concave die (200) and the convex die (100) are respectively nested into the lower part and the upper part of the inner die sleeve (300), the vertical center of the convex die (100) and the vertical center of the concave die (200) are positioned in a centering way through the inner die sleeve (300), and the bulge (110) of the convex die (100) and the groove (210) of the concave die (200) are matched together to form a forming cavity for forming the non-uniform-thickness curved glass; the outer die sleeve (400) is nested outside the inner die sleeve (300) and used for limiting the pressing position of the convex die (100).

2. The non-isopachous curved glass net shaping mold of claim 1, wherein: the convex die (100), the concave die (200) and the inner die sleeve (300) are all made of tungsten carbide or tungsten-nickel alloy, and the outer die sleeve (400) is made of heat-resistant stainless steel; the surface roughness of the protrusions (110) is 0-10 nm, and the surface roughness of the grooves (210) is 0-10 nm.

3. The non-isopachous curved glass net shaping mold of claim 1, wherein: the lower surface part of the convex die (100) on the periphery of the bulge (110) is a lower convex die end surface (120), and the upper surface part of the concave die (200) on the periphery of the groove (210) is an upper concave die end surface (220); when the forming die is used for die assembly, the gap between the lower end face (120) of the male die and the upper end face (220) of the female die is 0.05-3 mm, the die parting surface of the female die (200) and the male die (100) is higher than the forming cavity by 0.3-10 mm on the horizontal height, the assembly gap between the inner die sleeve (300) and the male die (100) and the assembly gap between the inner die sleeve (200) and the female die (100) are 0.001-0.01 mm, and the assembly gap between the outer die sleeve (400) and the inner die sleeve (300) is 1-4 mm.

4. The non-isopachous curved glass net shaping mold according to any of claims 1 to 3, wherein: the inner die sleeve (300) is provided with at least two first through holes (310), and the outer die sleeve (400) is provided with second through holes (410) which are correspondingly communicated with the first through holes (310) one by one; the diameter of the first through hole (310) is 2-5 mm, and the diameter of the second through hole (410) is 2-6 mm.

5. The non-isopachous curved glass net shaping mold of claim 4, wherein: the inner die sleeve (300) comprises at least two straight walls, and any two adjacent straight walls are in transition connection through an arc-shaped structure; each arc-shaped structure is provided with a first through hole (310), and each straight wall is provided with 1-3 first through holes (310).

6. The design method of the prefabricated member for net forming the curved glass with non-equal thickness is characterized in that: the non-uniform thickness curved glass net shape forming mold according to any one of claims 1 to 5, wherein the preform is designed as follows;

firstly, designing a preform according to the volume of a non-uniform-thickness curved glass element to be manufactured and the shape and size of a groove (210) of a concave die (200);

secondly, optimizing the shape and size of the initial blank of the prefabricated part by using numerical simulation software according to the principle that materials in all directions simultaneously reach the farthest end and synchronously complete mold filling in all directions to obtain a primary optimized blank of the prefabricated part;

setting the horizontal left-right direction of the groove (210) of the concave die (200) as a horizontal X direction, setting the horizontal front-back direction of the groove (210) of the concave die (200) as a horizontal Y direction, and optimizing the preform primary optimization blank again by using three-dimensional design software to obtain a preform secondary optimization blank; when the secondary optimized blank of the prefabricated member is aligned and placed in the groove (210), the distance between the side surface of the secondary optimized blank of the prefabricated member and the inner wall of the groove (210) in the horizontal X direction is less than or equal to 0.08mm, and the distance between the side surface of the secondary optimized blank of the prefabricated member and the inner wall of the groove (210) in the horizontal Y direction is less than or equal to 0.08 mm;

step four, according to a formula: calculating the final mass of the prefabricated member, wherein the mass M of the prefabricated member is (V-A x (0.005-0.1)) × rho; in the formula, V represents the volume of a forming cavity of the non-uniform thickness curved glass net forming die, A represents the area of the peripheral edge end faces of the non-uniform thickness curved glass element, and rho represents the material density of the non-uniform thickness curved glass; and calculating the final thickness of the prefabricated member according to the rho and the final quality of the prefabricated member and the area of the upper surface or the lower surface of the secondary optimized blank of the prefabricated member, and designing the prefabricated member.

7. A prefab for net shaping non-uniform thickness curved surface glass, its characterized in that: the method for designing a preform for net shaping curved glass with non-uniform thickness according to claim 6, wherein the quality, shape and size of the preform are designed, and the preform is obtained by drawing materials according to the designed quality, shape and size.

8. The net forming process of the non-uniform-thickness curved glass is characterized by comprising the following steps of: forming the non-uniform-thickness curved glass by using the non-uniform-thickness curved glass net forming mold as defined in any one of claims 1 to 5 and the preform for net forming the non-uniform-thickness curved glass as defined in claim 7 according to the following steps;

s1, loading: placing the prefabricated member at the notch of the groove (210) of the female die (200), nesting the male die (100) into the upper part of the inner die sleeve (300) in an unclamped state, and finally installing the outer die sleeve (400) to finish loading;

s2, removing oxygen: placing the forming mold loaded with the prefabricated member into an independent space filled with nitrogen, and purging the forming mold for 120-400 seconds by using the nitrogen;

s3, preheating: placing the molding die loaded with the prefabricated part into a preheating station for preheating treatment;

s4, molding: placing the preheated forming mold on a forming station, heating and forming the forming mold, and sequentially performing three stages of hot bending, mold pressing and pressure maintaining on the inner prefabricated member of the forming mold to obtain the non-uniform-thickness curved glass by pressing; during the forming process, the forming temperature is controlled at The glass has a viscosity of 10^7.6The temperature corresponding to poise; in the hot bending stage, closing the forming die, controlling the pressure to be 0.35-0.5 Mpa, and controlling the hot bending time to be 0.23t +/-20 s; in the mould pressing stage, the pressure is controlled to be 0.65-0.85 Mpa, and the mould pressing time is 0.69t +/-20 s; in the pressure maintaining stage, the pressure is controlled to be 0.3-0.4 Mpa, and the pressure maintaining time is 0.08t +/-10 s; wherein the time t is 120-400 s;

s5, annealing: annealing the non-uniform-thickness curved glass obtained by pressing and a forming die;

s6, cooling: cooling the annealed non-uniform-thickness curved glass and the forming mold;

s7, unloading: and taking the cooled non-uniform-thickness curved glass out of the forming die.

9. The process for net shaping of non-isopachous curved glass as in claim 8, wherein: in the step S3, carrying out N-stage gradual temperature rise preheating on the deaerated forming mold and the deaerated prefabricated part, wherein N is an integer larger than or equal to 3, and the heating time of each stage is 120-400S; heating temperature T of stage 1₁Tg-100 ℃ to Tg-10 ℃, Tg being the transition temperature of the glass; heating temperature T of Nth stage_NThe difference between the molding temperature and the heating temperature is 0-20 ℃, and the heating temperature in other stages is T_N-1＝T_N-2+(△T±40)℃，△T＝(T_N-T₁)/(N-1)。

10. The process for net shaping of non-isopachous curved glass as in claim 8, wherein: in the step S5, performing M-stage gradual cooling annealing on the non-uniform-thickness curved glass obtained by pressing and a forming mold, wherein M is an integer greater than or equal to 3, and the annealing time of each stage is 120-400S; and at least the following three stages are included in the M stages and are respectively marked as the Mi stage, the Mj stage and the Mk stage; the annealing temperature in the Mi stage is Tg + 5-Tg +30 ℃, and the pressure is controlled to be 0.05-0.2 Mpa; m thThe annealing temperature of the j stage is The glass has a viscosity of 10^14.5The temperature corresponding to the time of the poise,the glass has a viscosity of 10¹³Controlling the temperature and pressure at 0.05-0.2 MPa; the annealing temperature of the Mk stage is The pressure is controlled to be 0.01-0.1 MPa.

11. The process for net shaping of curved glass with non-uniform thickness according to any one of claims 8 to 10, wherein: further comprising step S8;

s8, precision annealing: and sending the taken out non-uniform-thickness curved glass into a precision annealing device for precision annealing treatment.

12. The non-equal thickness curved glass is characterized in that: the non-uniform thickness curved glass net-shape forming process as claimed in any one of claims 8 to 11.

Technical Field

The invention belongs to the technical field of glass processing, and particularly relates to a non-uniform-thickness curved glass net forming process, a mold, a prefabricated member and a design method thereof.

Background

At present, a non-uniform-thickness curved glass element is generally machined by a CNC machine in a whole block, and a concave surface and a convex surface are required to be dug out firstly and then polished to obtain the non-uniform-thickness curved glass element; the processing by the process has the problems of extremely low material utilization rate, long time consumption, low efficiency, low yield, high cost, poor surface roughness, difficult polishing and the like.

One processing method of the curved glass element is hot bending forming, namely, hot pressing equipment is used for processing and forming through processes of preheating, hot bending, cooling, CNC mechanical cutting of excess materials, polishing and the like. Another processing mode is that hot bending and hot suction combined forming is adopted, namely a vacuum adsorption structure is arranged on a lower die, firstly hot bending forming is carried out to obtain glass blank preliminary deformation, then hot suction forming is carried out to obtain curved surface glass, after cooling, CNC mechanical cutting excess material, polishing and other processing are carried out to obtain a final product, for example: the Chinese utility model with the authorization notice number of CN211311304U is processed in the way. The two processing modes are essentially hot bending forming, the forming pressure is small, but only the equal-thickness curved surface can be obtained, and the processing procedures of CNC mechanical cutting excess material, polishing and the like are required after cooling, so that the glass excess material is more, the procedures are more, the cost is high, the efficiency is low, and the forming process cannot obtain the non-equal-thickness curved surface glass element.

Chinese patent application publication No. CN112759236A, which discloses a method for forming curved glass elements with unequal thickness, wherein the forming temperature is increased to a temperature range above the softening point temperature of the glass based on the hot bending method: i.e. the forming temperature is that the glass viscosity is 10^3.7Pa·s～10^6.6The temperature corresponding to Pa.s is characterized in that the viscosity of the glass is very low, the glass has better fluidity, and the glass can be better filled into the gaps of the die to obtain the curved glass with different thicknesses. But because the forming temperature is very high, the die and the glass are interacted, the die is easy to stick, and the service life of the die is low. The recommended graphite material for the mold material has poor glass surface quality, and the mold is easy to be oxidized and the like to deteriorate so as to introduce impuritiesAnd the like, and this process also requires subsequent CNC machining resection anticipation and polishing processes.

Disclosure of Invention

The invention provides a net forming die for non-uniform-thickness curved glass, and aims to improve the utilization rate of materials in the process of manufacturing non-uniform-thickness curved glass elements and reduce the processing cost.

The technical scheme adopted by the invention for solving the technical problems is as follows: the non-uniform thickness curved surface glass net forming die comprises a convex forming die, a concave forming die, an inner die sleeve and an outer die sleeve;

the lower part of the convex section mould is provided with a bulge, the bulge comprises a connecting part and a profiling part arranged on the lower side of the connecting part, the profiling part comprises a profiling surface, the profiling surface comprises a middle plane and two convex cambered surfaces respectively arranged at the left end and the right end of the middle plane, and the convex cambered surfaces are in smooth transition connection with the middle plane;

the upper part of the concave section mould is provided with a groove, the groove comprises a notch matched with the convex connecting part and a forming part arranged on the lower side of the notch, and the forming part comprises a forming surface corresponding to the middle plane of the pressing surface and two concave cambered surfaces respectively arranged at the left end and the right end of the forming surface;

when the forming mold is closed, the concave section mold and the convex section mold are respectively nested into the lower part and the upper part of the inner mold sleeve, the vertical center of the convex section mold and the vertical center of the concave section mold are positioned in a centering way through the inner mold sleeve, and the bulge of the convex section mold and the groove of the concave section mold are matched together to form a forming cavity for forming the non-uniform-thickness curved glass; the outer die sleeve is nested outside the inner die sleeve and used for limiting the pressing position of the convex die.

Further, the convex section mould, the concave section mould and the inner mould sleeve are all made of tungsten carbide or tungsten-nickel alloy, and the outer mould sleeve is made of heat-resistant stainless steel; the surface roughness of the convex pattern die is 0-10 nm, and the surface roughness of the concave pattern die is 0-10 nm.

Further, the lower surface part of the convex die on the periphery of the protrusion is the lower end surface of the convex die, and the upper surface part of the concave die on the periphery of the groove is the upper end surface of the concave die; when the forming die is used for die assembly, the gap between the lower end face of the male die and the upper end face of the female die is 0.05-3 mm, the die parting surface of the female die and the male die is higher than the forming cavity by 0.3-10 mm on the horizontal height, the assembly gaps of the inner die sleeve and the male die and the female die are 0.001-0.01 mm, and the assembly gap of the outer die sleeve and the inner die sleeve is 1-4 mm.

Furthermore, at least two first through holes are formed in the inner die sleeve, and second through holes which are communicated with the first through holes in a one-to-one correspondence mode are formed in the outer die sleeve; the diameter of the first through hole is 2-5 mm, and the diameter of the second through hole is 2-6 mm.

Further, the inner mold sleeve comprises at least two straight walls, and any two adjacent straight walls are in transition connection through an arc-shaped structure; a first through hole has all been seted up on each arc structure, has all seted up 1 ~ 3 first through holes on each straight wall.

The invention also provides a design method of the prefabricated member for net forming of the non-uniform thickness curved glass, according to the non-uniform thickness curved glass net forming mold, the prefabricated member is designed according to the following steps;

designing a preform according to the volume of a non-uniform-thickness curved glass element to be manufactured and the shape and size of a groove of a concave die;

secondly, optimizing the shape and size of the initial blank of the prefabricated part by using numerical simulation software according to the principle that materials in all directions simultaneously reach the farthest end and synchronously complete mold filling in all directions to obtain a primary optimized blank of the prefabricated part;

setting the horizontal left and right directions of the groove of the concave die as horizontal X directions, setting the horizontal front and back directions of the groove of the concave die as horizontal Y directions, and optimizing the primary optimized blank of the prefabricated part again by using three-dimensional design software to obtain a secondary optimized blank of the prefabricated part; when the secondary optimized blank of the prefabricated member is aligned and placed in the groove, the distance between the side surface of the secondary optimized blank of the prefabricated member and the inner wall of the groove in the horizontal X direction is less than or equal to 0.08mm, and the distance between the side surface of the secondary optimized blank of the prefabricated member and the inner wall of the groove in the horizontal Y direction is less than or equal to 0.08 mm;

step four, according to a formula: calculating the final mass of the prefabricated member, wherein the mass M of the prefabricated member is (V-A x (0.005-0.1)) × rho; in the formula, V represents the volume of a forming cavity of the non-uniform thickness curved glass net forming die, A represents the area of the peripheral edge end faces of the non-uniform thickness curved glass element, and rho represents the material density of the non-uniform thickness curved glass; and calculating the final thickness of the prefabricated member according to the rho and the final quality of the prefabricated member and the area of the upper surface or the lower surface of the secondary optimized blank of the prefabricated member, and designing the prefabricated member.

The invention also provides a prefabricated member for net forming of the non-uniform thickness curved glass, the quality, the shape and the size of the prefabricated member are designed by the design method for the net forming of the non-uniform thickness curved glass, and the prefabricated member is obtained by obtaining materials according to the designed quality, shape and size.

The invention also provides a non-uniform thickness curved glass net forming process, which adopts the non-uniform thickness curved glass net forming mold and the prefabricated member for non-uniform thickness curved glass net forming to form the non-uniform thickness curved glass according to the following steps;

s1, loading: placing the prefabricated part at the notch of the groove of the concave die, nesting the convex die into the upper part of the inner die sleeve in the state of not closing the die, and finally installing the outer die sleeve to finish loading;

s2, removing oxygen: placing the forming mold loaded with the prefabricated member into an independent space filled with nitrogen, and purging the forming mold for 120-400 seconds by using the nitrogen;

s3, preheating: placing the molding die loaded with the prefabricated part into a preheating station for preheating treatment;

s4, molding: placing the preheated forming mold on a forming station, heating and forming the forming mold, and sequentially performing three stages of hot bending, mold pressing and pressure maintaining on the inner prefabricated member of the forming mold to obtain the non-uniform-thickness curved glass by pressing; during the forming process, the forming temperature is controlled at The glass has a viscosity of 10^7.6The temperature corresponding to poise; in the hot bending stage, closing the forming die, controlling the pressure to be 0.35-0.5 Mpa, and controlling the hot bending time to be 0.23t +/-20 s; in the mould pressing stage, the pressure is controlled to be 0.65-0.85 Mpa, and the mould pressing time is 0.69t +/-20 s; in the pressure maintaining stage, the pressure is controlled to be 0.3-0.4 Mpa, and the pressure maintaining time is 0.08t +/-10 s; wherein the time t is 120-400 s;

s5, annealing: annealing the non-uniform-thickness curved glass obtained by pressing and a forming die;

s6, cooling: cooling the annealed non-uniform-thickness curved glass and the forming mold;

s7, unloading: and taking the cooled non-uniform-thickness curved glass out of the forming die.

Further, in step S3, performing N-stage stepwise temperature rise preheating on the deaerated forming mold and the deaerated preform, wherein N is an integer greater than or equal to 3, and the heating time of each stage is 120-400S; heating temperature T of stage 1₁Tg-100 ℃ to Tg-10 ℃, Tg being the transition temperature of the glass; heating temperature T of Nth stage_NThe difference between the molding temperature and the heating temperature is 0-20 ℃, and the heating temperature in other stages is T_N-1＝T_N-2+(△T±40)℃，△T＝(T_N-T₁)/(N-1)。

Further, in step S5, performing M-stage gradual cooling annealing on the pressed non-uniform-thickness curved glass and the forming mold, where M is an integer greater than or equal to 3, and the annealing time of each stage is 120-400S; and at least the following three stages are included in the M stages and are respectively marked as the Mi stage, the Mj stage and the Mk stage; the annealing temperature in the Mi stage is Tg + 5-Tg +30 ℃, and the pressure is controlled to be 0.05-0.2 Mpa; the annealing temperature in the Mj stage is The glass has a viscosity of 10^14.5Corresponding when parkedThe temperature of the mixture is controlled by the temperature,the glass has a viscosity of 10¹³Controlling the temperature and pressure at 0.05-0.2 MPa; the annealing temperature of the Mk stage isThe pressure is controlled to be 0.01-0.1 MPa.

Further, the process further includes step S8;

s8, precision annealing: and sending the taken out non-uniform-thickness curved glass into a precision annealing device for precision annealing treatment.

The invention also provides the non-uniform-thickness curved glass which is prepared by the non-uniform-thickness curved glass net forming process.

The invention has the beneficial effects that:

(1) the forming mold provided by the invention can enclose a forming cavity for forming the non-uniform-thickness curved glass through the convex section mold and the concave section mold which are matched together, and can form the softened prefabricated member into the required non-uniform-thickness curved glass; meanwhile, the vertical center of the convex section mould and the vertical center of the concave section mould can be positioned in a centering way through the inner mould sleeve, the degree of freedom of the convex section mould and the concave section mould in the horizontal direction is limited, and deviation is prevented, so that the surface center deviation of the upper surface and the lower surface of the obtained non-uniform-thickness curved glass is less than 0.01 mm; the outer die sleeve can control the down dead point of the convex die during profiling, so that the thickness of the non-uniform-thickness curved glass is accurately controlled; therefore, the forming die can be used for a precise net forming process, and matched with a precisely designed prefabricated member, the non-uniform-thickness curved glass can be manufactured and formed at one time, the utilization rate of materials, the processing efficiency and the yield in the process of manufacturing the non-uniform-thickness curved glass are improved, and the processing cost is reduced.

(2) The first through hole is formed in the inner die sleeve, the second through hole is formed in the outer die sleeve, and the functions of exhausting, radiating, protecting inert gas outside the die and the like flowing into the die in the process of forming the non-uniform-thickness curved glass can be achieved; by controlling the fit clearance, the surface roughness and the like of the die, the non-uniform thickness curved glass can be manufactured and molded at one time, and the surface quality of the non-uniform thickness curved glass is ensured.

(3) The design method of the prefabricated member provided by the invention can ensure that the manufactured prefabricated member can prevent the deviation of the prefabricated member in the forming process by accurately designing the prefabricated member, and the deformation and flow of the prefabricated member can basically meet the requirement of synchronously completing mold filling in all directions, thereby realizing net forming.

(4) The forming process provided by the invention adopts the forming die to manufacture the non-uniform-thickness curved glass, and the forming die and the prefabricated member are deoxidized in the manufacturing process, so that impurities caused by deterioration such as oxidation in the using process of the forming die can be prevented, and the quality of the manufactured non-uniform-thickness curved glass is ensured; in addition, the molding process is carried out by stages of pressing, and the temperature, the pressure and the time of each pressing stage are reasonably controlled, so that not only can net molding be realized and the glass is fully filled, but also the surface quality of the manufactured non-uniform-thickness curved glass can be improved. The non-uniform-thickness curved glass manufactured by the molding process has good surface quality and qualified dimensional precision, does not need to be machined and subjected to excess material removal, polishing and other treatments by CNC (computerized numerical control), and the utilization rate of the glass material can basically reach 100%; the problems of extremely low utilization rate of glass materials, long consumed time, low efficiency, low yield, high cost, poor surface roughness, difficulty in polishing and the like in the conventional mechanical processing are solved. In addition, the forming temperature is lower in the process of pressing the non-uniform-thickness curved glass by using the forming die and the process provided by the invention, the service life of the forming die is prolonged, and the phenomenon of die sticking of the glass is basically avoided.

(5) The preheating and annealing process is reasonably controlled in the manufacturing process, so that the non-uniform-thickness curved glass is prevented from cracking; the processing efficiency and the yield of the manufactured non-uniform-thickness curved glass are ensured, and the processing cost is favorably reduced.

(6) Compared with the prior art, the forming process provided by the invention combines hot bending, mould pressing and pressure maintaining for forming, wherein the hot bending mainly has the same function as preforming to obtain a curved surface, and exhaust, good positioning of a prefabricated part and the like are also ensured in the hot bending process; the mould pressing is to press the prefabricated part with a large force, so that the material of the prefabricated part flows along the circumferential direction, the thickness of the prefabricated part is changed, and the curved glass with unequal thickness is manufactured.

(7) Compared with the prior art, the forming process provided by the invention can form curved glass with non-uniform thickness, but does not increase the forming temperature and the quality of a prefabricated part, has good surface quality and does not need subsequent processing; the reason is as follows: 1) the molding temperature is lower than the softening point temperature of the glass and is almost the same as the hot bending molding temperature; the forming die material adopts high-temperature-resistant high-strength alloy such as WC and the like, so that glass with lower temperature can deform and flow by adopting higher pressure during forming; in addition, in order to reduce the glass flow resistance, the surface roughness of a mold cavity is improved to be less than 10 nm; 2) the invention provides a forming die capable of precisely and net-forming non-uniform-thickness curved glass and a design method of a prefabricated member for net-forming non-uniform-thickness curved glass, wherein the quality of the designed prefabricated member is slightly lower than that of a product, and the material utilization rate can reach 100%; 3) because the glass forming temperature is lower, the surface roughness of the mold forming cavity is very high, the dimensional accuracy is high, and the prefabricated part is reasonably designed; in the mould pressing stage during forming, the flow deformation of the prefabricated part is small, so that the produced product has good surface quality and high dimensional precision, and subsequent reprocessing is not needed.

Drawings

FIG. 1 is a three-dimensional exploded view of a non-uniform thickness curved glass net-shape mold according to the present invention;

FIG. 2 is a schematic view of an implementation structure of the non-uniform thickness curved glass net-forming mold according to the present invention;

FIG. 3 is a schematic view of the process of the present invention for net-shaping of non-uniform thickness curved glass;

FIG. 4 is a schematic diagram of an implementation structure of the non-uniform thickness special-shaped watch cover manufactured in example 3;

FIG. 5 is a schematic plan view of a preform designed in example 2;

FIG. 6 is a first analysis diagram of simulation of compression molding values during the design of a preform;

FIG. 7 is a second analysis diagram of simulation of compression molding values during the design of the preform;

labeled as: the special-shaped watch cover comprises a convex die 100, a protrusion 110, a profiling surface 111, a stepped surface 112, a male die lower end surface 120, a concave die 200, a groove 210, a forming surface 211, a female die upper end surface 220, an inner die sleeve 300, a first through hole 310, an outer die sleeve 400, a second through hole 410, a prefabricated part 5, a non-uniform-thickness special-shaped watch cover 6, a watch cover body bottom surface 61, a watch cover high side wall 62 and a watch cover low side wall 63.

Detailed Description

The invention is further described below with reference to the figures and examples.

Referring to fig. 1 and 2, the non-uniform thickness curved glass net forming mold includes a convex mold 100, a concave mold 200, an inner mold 300 and an outer mold 400;

the lower part of the convex pattern die 100 is provided with a bulge 110, the bulge 110 comprises a connecting part and a profiling part arranged on the lower side of the connecting part, the profiling part comprises a profiling surface 111, the profiling surface 111 comprises a middle plane and two convex arc surfaces respectively arranged at the left end and the right end of the middle plane, and the convex arc surfaces are in smooth transition connection with the middle plane;

the upper part of the female die 200 is provided with a groove 210, the groove 210 comprises a notch matched with the connecting part of the protrusion 110 and a forming part arranged on the lower side of the notch, and the forming part comprises a forming surface 211 corresponding to the middle plane of the pressing surface 111 and two concave arc surfaces respectively arranged at the left end and the right end of the forming surface 211;

when the forming mold is closed, the concave mold 200 and the convex mold 100 are respectively nested into the lower part and the upper part of the inner mold sleeve 300, the vertical center of the convex mold 100 and the vertical center of the concave mold 200 are positioned in a centering way through the inner mold sleeve 300, and the bulge 110 of the convex mold 100 and the groove 210 of the concave mold 200 are matched together to form a forming cavity for forming the non-uniform-thickness curved glass; the outer mold 400 is nested outside the inner mold 300 to limit the pressing position of the male mold 100.

When the forming die is used for producing the non-uniform-thickness curved glass, the non-uniform-thickness curved glass is usually placed into a precision press, the forming die and the inner prefabricated part of the forming die are heated by controlling the precision press, and the prefabricated part is net formed into the non-uniform-thickness curved glass by controlling the technological parameters of the precision press, such as the temperature rise and fall rate, the pressure, the period and the like of the forming die, so that the utilization rate, the processing efficiency and the yield of materials in the whole production process are high. The net forming means forming with a material utilization rate of 100% and no excess material.

Wherein, the male mold 100 and the female mold 200 are mainly used for matching together and profiling the preform placed in the groove 210; the male mold 100 and the female mold 200 are generally made of a high temperature resistant alloy, preferably tungsten carbide or tungsten-nickel alloy; the convex die 100 is provided with the protrusion 110, and the concave die 200 is provided with the groove 210, so that the convex die and the concave die are matched to form a forming cavity with the same shape as the non-uniform-thickness curved glass; in order to improve the surface quality of the manufactured non-uniform-thickness curved glass, mechanical processing such as surface polishing is not carried out after the profiling is finished, and the surface roughness of the protrusions 110 and the grooves 210 is generally less than or equal to 10nm, preferably less than or equal to 5 nm.

Specifically, the lower surface portion of the male mold 100 around the protrusion 110 is a male lower end surface 120, and the upper surface portion of the female mold 200 around the groove 210 is a female upper end surface 220; when the forming die is closed, the gap between the lower end surface 120 of the male die and the upper end surface 220 of the female die is 0.05-3 mm, so that over-limitation can be prevented, and the compression quality is ensured;

preferably, when the forming mold is closed, the parting surface of the female mold 200 and the male mold 100 is higher than the forming cavity by 0.3 to 10mm in the horizontal height.

The inner die sleeve 300 is mainly used for centering and positioning the vertical center of the convex die 100 and the vertical center of the concave die 200, limiting the degree of freedom of the convex die 100 and the concave die 200 in the horizontal direction, preventing deviation and ensuring no vibration, and generally controlling the assembly clearance of the inner die sleeve 300 and the convex die 100 and the concave die 200 to be 0.001-0.01 mm, so that the surface center deviation of the upper surface and the lower surface of the prepared non-uniform-thickness curved glass can be ensured to be less than 0.01 mm; for the convenience of assembly, corners of the upper and lower ends of the inner mold sleeve 300 are generally chamfered.

The outer die sleeve 400 is mainly used for controlling the down dead point of the convex die 100 during profiling, so that the thickness of the non-uniform-thickness curved glass is accurately controlled; the assembly gap between the outer mold 400 and the inner mold 300 is generally controlled to be 1 to 4 mm.

Preferably, as shown in fig. 1 and 2, at least two first through holes 310 are formed in the inner mold shell 300, and the first through holes 310 correspond to the upper end of the female mold 200; the number of the first through holes 310 is at least two, and the first through holes are uniformly distributed along the circumferential direction of the inner die sleeve 300; the outer die sleeve 400 is provided with second through holes 410 which are in one-to-one correspondence communication with the first through holes 310; the diameter of the first through hole 310 is 2-5 mm, and the diameter of the second through hole 410 is 2-6 mm. The first through hole 310 is formed in the inner die sleeve 300, and the second through hole 410 is formed in the outer die sleeve 400, so that the functions of exhausting and dissipating heat in the process of forming the non-uniform-thickness curved glass, protecting the mold by allowing inert gas outside the mold to flow into the mold, and the like can be achieved.

On the basis, in order to facilitate deoxidization, exhaust and heat dissipation in deoxidization, preheating, molding and annealing cooling, the inner die sleeve 300 is designed into a structure that the inner die sleeve 300 comprises at least two straight walls, and any two adjacent straight walls are in transition connection through an arc-shaped structure; each arc-shaped structure is provided with a first through hole 310, and each straight wall is provided with 1-3 first through holes 310; the number and position of the second through holes 410 correspond to those of the first through holes 310.

The invention also provides a design method of the prefabricated member for net forming the non-uniform thickness curved glass, so as to accurately, quickly and effectively design the prefabricated member of the non-uniform thickness curved glass required by profiling, and the design method designs the prefabricated member according to the following steps according to the non-uniform thickness curved glass net forming mould;

step one, designing a preform according to the volume of a non-uniform-thickness curved glass element to be manufactured and the shape and size of a groove 210 of a concave die 200;

secondly, according to the principle that materials flow in all directions reach the farthest end at the same time and the filling is completed in all directions synchronously, optimizing the shape and the size of the initial blank of the prefabricated part by using numerical simulation software to obtain a primary optimized blank of the prefabricated part, wherein the shape and the size are as shown in fig. 6 and 7; performing simulation analysis on the flowing and mold filling process of the glass material by using numerical simulation software, specifically, aligning and placing the primary optimized blank of the prefabricated member in the groove 210 of the concave mold 200, wherein the primary optimized blank of the prefabricated member deforms in the mold pressing forming process, and the glass material flows towards the periphery and can fill the farthest space of the molding cavity and reach the farthest end at the same time, so that the requirement that the material flows in all directions reach the farthest end at the same time and the mold filling principle is synchronously completed in all directions is met; for example: the primary optimized preform is placed in alignment in the recess 210 of the female mould 200, at any 7 points in different directions on the primary optimized preform, which points are directed in the respective flow directions and reach the furthest end of the mould cavity during the moulding process;

setting the horizontal left-right direction of the groove 210 of the concave die 200 as a horizontal X direction, setting the horizontal front-back direction of the groove 210 of the concave die 200 as a horizontal Y direction, and optimizing the primary optimized blank of the prefabricated part again by using three-dimensional design software to obtain a secondary optimized blank of the prefabricated part; when the secondary optimized blank of the prefabricated member is aligned and placed in the groove 210, the distance between the side surface of the secondary optimized blank of the prefabricated member and the inner wall of the groove 210 in the horizontal X direction is less than or equal to 0.08mm, and the distance between the side surface of the secondary optimized blank of the prefabricated member and the inner wall of the groove 210 in the horizontal Y direction is less than or equal to 0.08 mm;

step four, according to a formula: calculating the final mass of the prefabricated member, wherein the mass M of the prefabricated member is (V-A x (0.005-0.1)) × rho; in the formula, V represents the volume of a forming cavity of the non-uniform thickness curved glass net forming die, A represents the area of the peripheral edge end faces of the non-uniform thickness curved glass element, and rho represents the material density of the non-uniform thickness curved glass; and (3) calculating the final thickness of the prefabricated member according to the rho and the final quality of the prefabricated member and the area of the upper surface or the lower surface of the secondary optimized blank of the prefabricated member, and designing the prefabricated member as shown in the reference of figure 5. The final thickness of the preform is generally 0.7 to 3 mm.

The invention also provides a prefabricated member for net forming of the non-uniform thickness curved glass, which is obtained by designing the quality, the shape and the size of the prefabricated member by the design method for net forming of the non-uniform thickness curved glass, taking materials according to the designed quality, the designed shape and the designed size and manufacturing. The fabricated part 5 is generally a flat plate structure, corners of the upper and lower surfaces are chamfered, and four corners are transition fillets with different diameters, as shown in fig. 5.

In order to improve the quality of the manufactured non-uniform thickness curved glass, the length and width dimensional accuracy of the prefabricated member is preferably controlled to be +/-0.01 mm, and the thickness dimensional accuracy is preferably controlled to be +/-0.008 mm.

The invention also provides a non-uniform thickness curved glass net forming process, which adopts the non-uniform thickness curved glass net forming mold and the pre-fabricated part for non-uniform thickness curved glass net forming to form the non-uniform thickness curved glass according to the following steps, and is combined with the steps shown in figure 3;

s1, loading: placing the prefabricated member at the notch of the groove 210 of the female die 200, nesting the male die 100 into the upper part of the inner die sleeve 300 in an unclamped state, and finally installing the outer die sleeve 400 to finish loading;

s2, removing oxygen: placing the forming mold loaded with the prefabricated member into an independent space filled with nitrogen, and purging the forming mold for 120-400 seconds by using the nitrogen;

s3, preheating: placing the molding die loaded with the prefabricated part into a preheating station for preheating treatment;

s4, molding: placing the preheated forming mold on a forming station, heating and forming the forming mold, and sequentially performing three stages of hot bending, mold pressing and pressure maintaining on the inner prefabricated member of the forming mold to obtain the non-uniform-thickness curved glass by pressing; hot bending is to bend the prefabricated part with a plane structure to form a curved glass piece with a certain curvature, but the thickness is not changed; the mould pressing is that after the hot bending is finished, higher pressure is loaded to change the thickness of the curved glass piece with a certain curvature, and the glass material flows along the thickness normal direction to fill the whole space of the forming cavity, so that the non-uniform-thickness curved glass is obtained; maintaining pressure, namely maintaining certain pressure after the molding is finished to shape the non-uniform-thickness curved glass; during the forming process, the forming temperature is controlled at The glass has a viscosity of 10^7.6The temperature corresponding to poise; in the hot bending stage, closing the forming die, controlling the pressure to be 0.35-0.5 Mpa, and controlling the hot bending time to be 0.23t +/-20 s; in the mould pressing stage, the pressure is controlled to be 0.65-0.85 Mpa, and the mould pressing time is 0.69t +/-20 s; in the pressure maintaining stage, the pressure is controlled to be 0.3-0.4 Mpa, and the pressure maintaining time is 0.08t +/-10 s; wherein the time t is 120-400 s;

s5, annealing: annealing the non-uniform-thickness curved glass obtained by pressing and a forming die;

s6, cooling: cooling the annealed non-uniform-thickness curved glass and the forming mold;

s7, unloading: and taking the cooled non-uniform-thickness curved glass out of the forming die.

The forming process adopts the forming mold and the prefabricated member to manufacture the non-uniform-thickness curved glass, and can prevent impurities from being introduced due to deterioration caused by oxidation and the like in the using process of the forming mold by removing oxygen from the forming mold and the prefabricated member, thereby ensuring the quality of the manufactured non-uniform-thickness curved glass; in addition, the glass can be fully filled and the surface quality of the manufactured non-uniform-thickness curved glass can be improved by pressing in stages and reasonably controlling the temperature, pressure and time of each pressing stage in the forming process. The non-uniform-thickness curved glass manufactured by the molding process has good surface quality and qualified dimensional precision, does not need to be machined and subjected to excess material removal, polishing and other treatments by CNC (computerized numerical control), and the utilization rate of the glass material can basically reach 100%; the problems of extremely low utilization rate of glass materials, long consumed time, low efficiency, low yield, high cost, poor surface roughness, difficulty in polishing and the like in the conventional mechanical processing are solved. In addition, the forming temperature is lower in the process of pressing the non-uniform-thickness curved glass by using the forming die and the process provided by the invention, the service life of the forming die is prolonged, and the phenomenon of sticking the glass die is avoided.

In order to ensure uniform preheating of the forming mold and the preform and to ensure that the preform does not burst, it is preferable that in step S3, the forming mold and the preform after oxygen removal are preheated by heating in N stages, where N is 3 or moreInteger, wherein the heating time of each stage is 120-400 s; heating temperature T of stage 1₁Tg-100 ℃ to Tg-10 ℃, Tg being the transition temperature of the glass; heating temperature T of Nth stage_NThe difference between the molding temperature and the heating temperature is 0-20 ℃, and the heating temperature in other stages is T_N-1＝T_N-2+(△T±40)℃，△T＝(T_N-T₁)/(N-1)。

In order to effectively reduce the internal stress of the non-uniform-thickness curved glass and prevent the non-uniform-thickness curved glass from cracking, preferably in step S5, performing M-stage gradual cooling annealing on the pressed non-uniform-thickness curved glass and a forming mold, wherein M is an integer greater than or equal to 3, and the annealing time of each stage is 120-400S; and at least the following three stages are included in the M stages and are respectively marked as the Mi stage, the Mj stage and the Mk stage; the annealing temperature in the Mi stage is Tg + 5-Tg +30 ℃, and the pressure is controlled to be 0.05-0.2 Mpa; the annealing temperature in the Mj stage is The glass has a viscosity of 10^14.5The temperature corresponding to the time of the poise,the glass has a viscosity of 10¹³Controlling the temperature and pressure at 0.05-0.2 MPa; the annealing temperature of the Mk stage is The pressure is controlled to be 0.01-0.1 MPa.

Considering that the non-uniform-thickness curved glass cooled in the forming press is still generally high in stress and easy to crack in the subsequent use process, the service life is shortened. In particular, some non-uniform thickness curved glass with high requirements on optical indexes has large internal residual stress, which affects the refractive index, the stability of some indexes and the like, so that it is necessary to apply precision annealing equipment to precisely anneal the non-uniform thickness curved glass to obtain the non-uniform thickness curved glass with smaller residual stress and better various optical indexes and stability.

Therefore, the molding process generally further includes step S8;

s8, precision annealing: and sending the taken out non-uniform-thickness curved glass into a precision annealing device for precision annealing treatment. In the precision annealing, thousands of pieces of curved glass with unequal thickness are generally put into precision annealing equipment together for precision annealing.

The invention also provides the non-uniform-thickness curved glass which is prepared by the non-uniform-thickness curved glass net forming process.

Example 1

The non-uniform thickness curved glass net forming mold comprises a convex mold 100, a concave mold 200, an inner mold sleeve 300 and an outer mold sleeve 400;

the lower part of the convex die 100 is provided with a bulge 110, the bulge 110 comprises a connecting part and a profiling part arranged on the lower side of the connecting part, the profiling part comprises a profiling surface 111, the profiling surface 111 comprises a middle plane and two convex arc surfaces respectively arranged at the left end and the right end of the middle plane, and the convex arc surfaces are in smooth transition connection with the middle plane;

the upper part of the female mold 200 is provided with a groove 210, the groove 210 comprises a notch matched with the connecting part of the protrusion 110 and a forming part arranged on the lower side of the notch, the forming part comprises a forming surface 211 corresponding to the middle plane of the molding surface 111 and two female arc surfaces respectively arranged at the left end and the right end of the forming surface 211, and the radian of the female arc surfaces is greater than that of the male arc surfaces;

the surface roughness of the protrusion 110 and the groove 210 is less than or equal to 8nm, and the coating treatment is carried out on the surface roughness;

the inner die sleeve 300 comprises four straight walls, and any two adjacent straight walls are in transition connection through an arc-shaped structure; the inner die sleeve 300 is provided with first through holes 310, the first through holes 310 correspond to the upper end of the female die 200, the number of the first through holes 310 is 8, each arc-shaped structure is provided with one first through hole 310, and each straight wall is provided with 1 first through hole 310; the outer die sleeve 400 is provided with second through holes 410, and the number of the second through holes 410 is equal to that of the first through holes 310 and the second through holes 410 are communicated in a one-to-one correspondence manner; the diameters of the first through hole 310 and the second through hole 410 are both 2.8 mm;

the male pattern die 100, the female pattern die 200, and the inner mold sleeve 300 are all made of tungsten carbide, and the outer mold sleeve 400 is made of heat-resistant stainless steel;

the assembly clearance between the inner die sleeve 300 and the male die 100 and the female die 200 is controlled to be 0.0065 mm; the assembly gap between the outer die sleeve 400 and the inner die sleeve 300 is controlled to be 2.5 mm;

when the forming mold is closed, the concave mold 200 and the convex mold 100 are respectively nested into the lower part and the upper part of the inner mold sleeve 300, the vertical center of the convex mold 100 and the vertical center of the concave mold 200 are positioned in a centering way through the inner mold sleeve 300, and the bulge 110 of the convex mold 100 and the groove 210 of the concave mold 200 are matched together to form a forming cavity for forming the non-uniform-thickness curved glass; the outer die sleeve 400 is nested outside the inner die sleeve 300 and used for limiting the pressing position of the male die 100; the parting surface of the concave section die 200 and the convex section die 100 is 1-4 mm higher than the molding cavity in the horizontal height; a gap of 0.1mm is maintained between the lower end face 120 of the male die and the upper end face 220 of the female die.

Example 2

According to the non-uniform thickness curved glass net forming mold in the embodiment 1, a prefabricated part is designed according to the following steps;

step one, designing a preform according to the volume of a non-uniform-thickness curved glass element to be manufactured and the shape and size of a groove 210 of a concave die 200; the non-uniform thickness curved surface glass element is a non-uniform thickness special-shaped watch cover 6 shown in figure 4, the preform is an upper surface chamfer and a lower surface chamfer, and 4 unequal diameter transition fillets are chamfered on 4 edges in the thickness direction; the length a of the preform is 43.30mm, the width b is 36.42mm, the transition fillet is 4-R9 x 9mm, and the chamfer angle is 4 x C0.1mm;

secondly, optimizing the initial blank of the prefabricated part by using numerical simulation software, namely, a polyflow, according to the principle that materials in all directions flow to the farthest end simultaneously and the filling is finished synchronously in all directions, so as to obtain a primary optimized blank of the prefabricated part; the length a of the primary optimized blank of the prefabricated part is 40.25mm, the width b of the primary optimized blank of the prefabricated part is 36.67mm, and the transition fillet is 4-R9.1 multiplied by 6.2 mm;

setting the horizontal left and right directions of the groove 210 of the concave die 200 as horizontal X directions, setting the horizontal front and back directions of the groove 210 of the concave die 200 as horizontal Y directions, and optimizing the primary optimized blank of the prefabricated part again by using three-dimensional design software solidworks to obtain a secondary optimized blank of the prefabricated part; when the secondary optimized blank of the prefabricated member is aligned and placed in the groove 210, the minimum distance between the side surface of the secondary optimized blank of the prefabricated member and the inner wall of the groove 210 in the horizontal X direction is 0.03mm, and the minimum distance between the side surface of the secondary optimized blank of the prefabricated member and the inner wall of the groove 210 in the horizontal Y direction is 0.02 mm; the length a of the secondary optimized blank of the prefabricated part is 42.25mm, the width b of the secondary optimized blank of the prefabricated part is 36.75mm, and the transition fillet is 4-R10 multiplied by 5.55 mm;

step four, according to a formula: calculating the final mass of the prefabricated member, wherein the mass M of the prefabricated member is (V-A x (0.005-0.1)) × rho; and calculating the final thickness of the preform to be 1.120mm according to the rho and the final quality of the preform and the area of the upper surface or the lower surface of the preform secondary optimization blank, and designing the preform 5 as shown in FIG. 5.

Example 3

The non-uniform thickness special-shaped watch cover 6 is manufactured by utilizing the non-uniform thickness curved surface glass net forming process provided by the invention, and the process is as follows:

s1, loading: placing the prefabricated member at the notch of the groove 210 of the female die 200, nesting the male die 100 into the upper part of the inner die sleeve 300 in an unclamped state, and finally installing the outer die sleeve 400 to finish loading;

s2, removing oxygen: placing the forming mold loaded with the prefabricated member into an independent space filled with nitrogen, and purging the forming mold for 260s by using the nitrogen;

s3, preheating: preheating the deoxidized forming die by heating step by step in 3 stages, wherein the heating temperature in the 1 st stage is 465 ℃, and the heating time is 260 s; the heating temperature of the 2 nd stage is 540 ℃, and the heating time is 260 s; the heating temperature of the 3 rd stage is 592 ℃ and the heating time is 260 s;

s4, molding: placing the preheated forming mold on a forming station, heating and forming the forming mold, and sequentially performing hot bending, mold pressing and pressure maintaining treatment on the inner prefabricated member of the forming mold, and pressing to obtain the non-uniform-thickness special-shaped watch cover 6; in the molding process, the molding temperature is controlled at 595 ℃; in the hot bending stage, the forming die is closed, the pressure is controlled to be 0.41Mpa, and the hot bending time is 50 s; in the mould pressing stage, closing the forming mould, controlling the pressure to be 0.81Mpa, and controlling the mould pressing time to be 190 s; in the pressure maintaining stage, the forming die is closed, the pressure is controlled to be 0.36Mpa, and the pressure maintaining time is 20 s;

s5, annealing: carrying out 3-stage gradual cooling annealing on the pressed special-shaped watch cover 6 with unequal thickness and the forming die, wherein the annealing temperature of the 1 st stage is 505 ℃, the pressure is controlled to be 0.12Mpa, and the annealing time is 260 s; the annealing temperature of the 2 nd stage is 481 ℃, the pressure is controlled to be 0.08Mpa, and the annealing time is 260 s; the annealing temperature of the 3 rd stage is 400 ℃, the pressure is controlled to be 0.02Mpa, and the annealing time is 260 s;

s6, cooling: cooling the annealed non-uniform-thickness special-shaped watch cover 6 and the forming die in two stages, wherein the cooling temperature in the 1 st stage is 200 ℃, and the cooling time is 260 s; the cooling temperature of the stage 2 is 28 ℃, and the cooling time is 260 s;

s7, unloading: the cooled non-uniform thickness contoured watch cover 6 is removed from the forming mold as shown in fig. 4.

The non-uniform thickness special-shaped watch cover 6 measured by a three-coordinate measuring instrument has the advantages that the middle thickness of the bottom surface 61 of the watch cover main body is 1.060mm, the arc height of the high side wall 62 of the watch cover is 3.481mm, the arc height of the low side wall 63 of the watch cover is 1.270mm, the outer length is 43.665mm, the outer width is 36.783mm, and the dimensional precision is qualified. The appearance of the whole non-uniform-thickness special-shaped watch cover 6 is detected, the surface quality is good, and the glass has no crack, concave-convex points, unfilled corners and stripes.