Forming tooling for ultra-thick double-curved plexiglass and its usage method

Abstract

The present invention provides a forming tooling for ultra-thick double-curved plexiglass and its usage method, which relates to a power output structure and includes a concave die mold base with guide wheels and a convex die mold base located above the concave die mold base and driven to lift by a hydraulic cylinder on the concave die mold base. A concave die body is provided on the concave die mold base, and a convex die body is provided on the convex die mold base. A vacuum suction pipe group is further arranged on the concave die mold base. The vacuum suction pipe group includes multiple groups of suction holes arranged on the surface of the concave die body, a suction pipe connected to the suction holes, and a vacuum pump connected to the suction pipe. The vacuum pump is used to extract the non-adhered air between the surface of the concave die body and the plexiglass during mold closing through the suction pipe and the suction holes. The present invention utilizes a large-scale forming device, adopts a forming device combining male and female die mold closing and vacuum thermoforming, and a special forming process to solve the problems of difficult forming and easy springback after forming of ultra-thick double-curved plexiglass with a thickness greater than 30 mm.

Description

Technical Field

[0001] The present invention relates to a forming processing device and method, in particular to a forming tooling for ultra-thick double-curvature plexiglass and its usage method. Background Art

[0002] At present, with the fourth-generation fighter jets gradually becoming the main combat models, the demand for integrated cockpit canopies is gradually increasing. In the future, except for unmanned aerial vehicles, most fighter jets will probably be equipped with integrated cockpit canopies. At the current stage in China, there are few manufacturers capable of producing and manufacturing this type of cockpit canopy, so there is a large gap in the industry.

[0003] The traditional cockpit canopy structure is generally divided into a fixed windshield and a movable canopy. The integrated cockpit canopy eliminates the interface between the traditional windshield and the canopy, integrating the windshield and the canopy into an integral form, improving the anti-bird strike performance and stealth performance. The integrated cockpit canopy adopts a double-curved special-shaped structure. As a large-sized part, it has a large single-piece weight and a relatively thick thickness. The problems exposed in the manufacturing process include the great difficulty in forming large-sized transparent parts, complex processes, long production cycles, and the difficulty in eliminating the peripheral skirt during the forming process. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a forming tooling for ultra-thick double-curvature plexiglass and its usage method. By using a large-scale forming device, a forming device combining male and female die clamping and vacuum thermoforming, and a special forming process, the problems of great difficulty in forming ultra-thick double-curvature plexiglass with a thickness greater than 30 mm and easy springback after forming are solved.

[0005] The present invention provides the following technical solutions:

[0006] A forming tooling for ultra-thick double-curvature plexiglass and its usage method, including a female die mold base with guide wheels and a male die mold base located above the female die mold base and driven to lift by a hydraulic cylinder on the female die mold base. The female die mold base with guide wheels can facilitate the transfer of the glass into the oven during the actual operation process. A female die body is provided on the female die mold base, and a male die body is provided on the male die mold base. The female die body and the male die body are used for clamping and forming ultra-thick double-curvature plexiglass with a thickness greater than 30 mm. A vacuum suction pipe group is also provided on the female die mold base. The vacuum suction pipe group includes multiple groups of suction holes arranged on the surface of the female die body, a suction pipe connected to the suction holes, and a vacuum pump connected to the suction pipe. The vacuum pump is used to extract the non-adhered air between the surface of the female die body and the plexiglass during clamping through the suction pipe and the suction holes, ensuring that the formed part fits the female die and maintaining the shape.

[0007] So far, a special forming and processing device for the present invention is designed. By adopting the form of hydraulic force application and vacuum pumping in cooperation to increase the forming force, the forming temperature can be appropriately reduced. Through vacuum thermoforming, it is ensured that the top surface of the transparent part closely adheres to the female die, so as to obtain more machining allowance for subsequent CNC milling of the outer shape.

[0008] Preferably, a placement rack group is further arranged on the female die mold base. The placement rack group includes two pairs of linear guide rail groups arranged at both ends of the female die body and two groups of glass placement rack angle steels horizontally installed between the two pairs of linear guide rail groups. Each pair of linear guide rail groups includes two groups of linear guide rail units distributed in an upward flared shape towards the outside. And both ends of the glass placement rack angle steel are slidably installed on two groups of linearly opposed linear guide rail units through their respective sliders, and are used to support and fix the glass blank before mold closing.

[0009] In actual operation, after the glass blank - flat glass is cut according to the cutting size, it is fixed to the glass placement rack angle steel with thick cotton ropes. Due to the adoption of the simulated forming state, after the device is pushed into the oven and heated to the softening temperature, and through the sliding traction of the linear guide rail units around the glass placement rack angle steel, the glass blank can be bent into a U - shape due to its own weight, achieving the effect of reducing the influence of the skirt edge by designing a special cutting shape.

[0010] Preferably, two groups of guide rods are respectively arranged at both ends of the female die mold base. The guide rods are in guiding connection with the male die mold base to ensure the stability when the male die mold base is lifted and lowered by the hydraulic cylinder.

[0011] Preferably, the female die body is positioned on the female die mold base through a number of partition reinforcing ribs one, and the male die body is positioned on the male die mold base through a number of partition reinforcing ribs two. Based on this, the lightness of the mold base can be ensured and the fixing stability can also be guaranteed.

[0012] Preferably, the partition reinforcing ribs one and the partition reinforcing ribs two are distributed in a pairwise up - and - down opposite manner. Therefore, when the female die body and the male die body are stamping and closing the mold, stamping deformation can be better avoided.

[0013] Preferably, after the glass blank is cut according to the cutting size, it is fixed to the glass placement rack angle steel with thick cotton ropes, so as to fix the glass blank to the glass placement rack angle steel. At the same time, through the sliding traction of the linear guide rail units around the glass placement rack angle steel, the glass blank can be bent into a U - shape due to its own weight, achieving the effect of reducing the influence of the skirt edge by designing a special cutting shape.

[0014] A method for using a forming tool for ultra - thick double - curvature plexiglass includes the following steps:

[0015] S1: Pre-bending forming: First, cut the glass blank according to the cutting size and fix it on the angle steel of the glass placement rack with thick cotton ropes. Then, push the female die mold base into the oven. The pre-bending forming temperature in the oven is set to 120°C - 130°C, and the heat preservation time is 2h - 3h to soften the glass blank. Through the sliding traction of the linear guide unit around the angle steel of the glass placement rack, the glass blank can be bent into a U-shaped semi-finished product due to its own weight.

[0016] S2: Die closing forming: Push the female die mold base completed in step S1 out of the oven, use a crane to hoist and install the male die mold base above the female die mold base, and fix the hydraulic cylinder to the male die mold base through the hydraulic flange. Then, push the female die mold base into the oven again. After heating the temperature in the oven to the die closing temperature of 135°C - 145°C, use the hydraulic cylinder to slowly control the female die body and the male die body to close to the limit in multiple times, and set the heat preservation time to 2h - 3h.

[0017] S3: Vacuum thermoforming: Turn on the vacuum pump under the heat preservation state in step S2, extract the remaining air between the surface of the female die body and the plexiglass to form a negative pressure, ensure that the transparent part is completely attached to the surface of the female die body, and keep the pressure for 2h - 3h and then cool down.

[0018] S4: Cooling and taking out the part: Cool down the temperature in the oven to room temperature with the vacuum pump turned on, then push out the forming tooling, remove the male die body through the crane, and remove the formed ultra-thick double-curvature plexiglass transparent part to complete the forming process.

[0019] The beneficial effects of the present invention are:

[0020] 1. The forming device and method of the present invention are applicable to the forming of non-oriented plexiglass. Ensure the fitting degree of the formed surface through hydraulic die closing extrusion. Finally, ensure that the surface of the top (where it may become thinner) of the transparent part is closely attached to the female die through vacuum thermoforming, striving for more machining allowance for the subsequent numerical control milling of the outer shape. The advantages of this forming method for double-curvature products are: The forming process can not only ensure the fitting degree of the surface but also reduce the thinning rate of the material thickness. And because of cooling after the male and female dies are closed, the cooling rates of the inner and outer surfaces of the transparent part are basically the same, and the stress difference between the inner and outer surfaces after cooling is small, and the formed part is not easy to rebound and deform.

[0021] 2. In the present invention, the transparent part material is YB-M-10 non-oriented plexiglass sheet. During the forming process, due to excessive curvature, skirt edges are likely to be generated around. Therefore, a special cutting shape is designed, and the hydraulic cylinder is used to apply force to slowly close the male and female dies. The surfaces of the male and female dies are machined according to the theoretical surface. By adopting the method of constant-temperature vacuum adsorption, the convex surface of the transparent part is closely attached to the female die of the tooling, reducing the thinning rate of the top of the transparent part and removing stress at the same time. Description of the drawings

[0022] The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the accompanying drawings:

[0023] Figure 1 is a three-dimensional schematic diagram of the present invention;

[0024] Figure 2 is a structural schematic diagram of the female die mold base;

[0025] Figure 3 is a structural schematic diagram of the male die mold base;

[0026] Markings in the figure:

[0027] 1. Female die mold base; 2. Male die mold base; 11. Guide wheel; 12. Hydraulic cylinder; 13. Female die body; 14. Suction pipeline; 15. Suction hole; 16. Linear guide rail group; 17. Angle steel for glass placement rack; 18. Guide rod; 19. Partition reinforcing rib 1; 21. Male die body; 22. Partition reinforcing rib 2. Detailed implementation manners

[0028] Embodiment 1

[0029] As Figures 1-3 shown, a forming tooling for ultra-thick double-curved plexiglass, in this embodiment, includes a female die mold base 1 with a guide wheel 11 and a male die mold base 2 located above the female die mold base 1 and driven to lift by a hydraulic cylinder 12 on the female die mold base 1. The female die mold base 1 with the guide wheel 11 can facilitate the transfer of the glass into the oven during the actual operation process. The female die mold base 1 is provided with a female die body 13, and the male die mold base 2 is provided with a male die body 21. The female die body 13 and the male die body 21 are used for clamping and forming ultra-thick double-curved plexiglass with a thickness greater than 30 mm. The female die mold base 1 is further provided with a vacuum suction pipe group. The vacuum suction pipe group includes multiple groups of suction holes 15 arranged on the surface of the female die body 13, a suction pipeline 14 connected to the suction holes 15, and a vacuum pump connected to the suction pipeline 14. The vacuum pump is used to extract the non-adhered air between the surface of the female die body 13 and the plexiglass during clamping through the suction pipeline 14 and the suction holes 15, ensuring that the formed part fits the female die and guaranteeing the prototype.

[0030] So far, a special forming processing device of the present invention is designed. By adopting the form of combining hydraulic force and vacuum pumping to increase the forming force, the forming temperature can be appropriately reduced. Through vacuum thermoforming, it is ensured that the top surface of the transparent part closely adheres to the female die, and more machining allowance can be obtained for the subsequent numerical control milling of the outer shape.

[0031] A placing rack group is further arranged on the female die mold base 1. The placing rack group includes two pairs of linear guide rail groups 16 arranged at both ends of the female die body 13 and two groups of glass placing rack angle steels 17 horizontally arranged between the two pairs of linear guide rail groups 16. Each pair of linear guide rail groups 16 includes two groups of linear guide rail units distributed in an upward flared shape towards the outside. Both ends of the glass placing rack angle steel 17 are slidably connected and installed on two groups of relatively distributed linear guide rail units for supporting and fixing the glass blank before mold clamping.

[0032] In actual operation, after the glass blank - flat glass is cut according to the cutting size, it is fixed on the glass placing rack angle steel 17 with thick cotton ropes. Since the simulated forming state is adopted, after the device is pushed into the oven and heated to the softening temperature, and through the sliding traction of the linear guide rail units around the glass placing rack angle steel 17, the glass blank can be bent into a U - shape due to its own weight, achieving the effect of reducing the influence of the skirt edge by designing a special cutting shape.

[0033] Two groups of guide rods 18 are further arranged at both ends of the female die mold base 1. The guide rods 18 are in guiding connection with the male die mold base 2 to ensure the stability when the hydraulic cylinder 12 drives the male die mold base 2 to lift and lower.

[0034] The female die body 13 is positioned on the female die mold base 1 through a number of partition reinforcing ribs one 19, and the male die body 21 is positioned on the male die mold base 2 through a number of partition reinforcing ribs two 22. Based on this, the lightness of the mold base can be ensured and the fixing stability can also be guaranteed.

[0035] The partition reinforcing ribs one 19 and the partition reinforcing ribs two 22 are distributed in a pairwise up - and - down relative manner. Therefore, when the female die body 13 and the male die body 21 are stamping and clamping the mold, stamping deformation can be better avoided.

[0036] After the glass blank is cut according to the cutting size, it is fixed on the glass placing rack angle steel 17 with thick cotton ropes to fix the glass blank on the glass placing rack angle steel 17. At the same time, through the sliding traction of the linear guide rail units around the glass placing rack angle steel 17, the glass blank can be bent into a U - shape due to its own weight, achieving the effect of reducing the influence of the skirt edge by designing a special cutting shape.

[0037] Embodiment 2

[0038] A using method of a forming tool for ultra - thick double - curvature plexiglass, based on the forming tool for ultra - thick double - curvature plexiglass described in Embodiment 1, includes the following steps:

[0039] S1: Pre-bending forming: First, cut the glass blank according to the cutting size and fix it on the angle steel 17 of the glass placement rack with thick cotton ropes. Then, push the female die mold base 1 into the oven. The pre-bending forming temperature in the oven is set to 120°C - 130°C, and the heat preservation time is 2h - 3h, so that the glass blank is softened. Through the sliding traction of the linear guide unit around the angle steel 17 of the glass placement rack, the glass blank can be bent into a U-shaped semi-finished product due to its own weight.

[0040] S2: Die closing forming: Push the female die mold base 1 that has completed step S1 out of the oven. Use a crane to hoist and install the male die mold base 2 above the female die mold base 1, and fix the hydraulic cylinder 12 and the male die mold base 2 through the hydraulic flange. Then, push the female die mold base 1 into the oven again. After heating the temperature in the oven to the die closing temperature of 135°C - 145°C, use the hydraulic cylinder 12 to slowly control the female die body 13 and the male die body 21 to close to the limit in multiple times, and set the heat preservation time to 2h - 3h.

[0041] S3: Vacuum thermoforming: Turn on the vacuum pump in the heat preservation state of step S2, extract the remaining air between the surface of the female die body 13 and the plexiglass to form a negative pressure, ensure that the transparent part is completely attached to the surface of the female die body 13, and keep the pressure for 2h - 3h and then cool down.

[0042] S4: Cooling and taking out the part: Cool down the temperature in the oven to room temperature with the vacuum pump turned on, then push out the forming tooling, remove the male die body 21 through a crane, and remove the formed ultra-thick double-curvature plexiglass transparent part to complete the forming process.

[0043] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A forming method for ultra-thick double-curved plexiglass, characterized in that, The forming tooling used in this method includes a concave die mold base (1) with guide wheels (11), and a convex die mold base (2) located above the concave die mold base (1) and driven to lift by a hydraulic cylinder (12) on the concave die mold base (1). A concave die body (13) is provided on the concave die mold base (1), and a convex die body (21) is provided on the convex die mold base (2). The concave die body (13) and the convex die body (21) are used for die closing to form an ultra-thick double-curved plexiglass with a thickness greater than 30 mm. A vacuum suction pipe group is also arranged on the concave die mold base (1). The vacuum suction pipe group includes multiple groups of suction holes (15) arranged on the surface of the concave die body (13), a suction pipe (14) connected to the suction holes (15), and a vacuum pump connected to the suction pipe (14). The vacuum pump is used to extract the non-adhered air between the surface of the concave die body (13) and the plexiglass during die closing through the suction pipe (14) and the suction holes (15); A placement rack group is also arranged on the concave die mold base (1). The placement rack group includes two pairs of linear guide rail groups (16) arranged at both ends of the concave die body (13) and two groups of glass placement rack angle steels (17) parallelly erected between the two pairs of linear guide rail groups (16). Each pair of linear guide rail groups (16) includes two groups of linear guide rail units distributed in an upward flared shape towards the outside, and both ends of the glass placement rack angle steel (17) are slidably mounted on two groups of relatively distributed linear guide rail units through their respective sliders, and are used to support and fix the glass blank before die closing; This method includes the following steps: S1: Pre-bending forming: First, cut the glass blank according to the cutting size and fix it on the glass placement rack angle steel (17) with thick cotton ropes. Then, push the concave die mold base (1) into the oven. The pre-bending forming temperature in the oven is set to 120°C - 130°C, and the heat preservation time is 2h - 3h, so that the glass blank is softened. Through the sliding traction of the linear guide rail units around the glass placement rack angle steel (17), the glass blank can be bent into a U-shaped semi-finished product due to its own weight; S2: Die closing forming: Push the concave die mold base (1) that has completed step S1 out of the oven, use a crane to hoist and install the convex die mold base (2) above the concave die mold base (1), and fix the hydraulic cylinder (12) and the convex die mold base (2) through a hydraulic flange. Then, push the concave die mold base (1) into the oven again. After raising the temperature in the oven to the die closing temperature of 135°C - 145°C, use the hydraulic cylinder (12) to slowly control the die closing of the concave die body (13) and the convex die body (21) in multiple times to the limit, and set the heat preservation time to 2h - 3h; S3: Vacuum thermoforming: Turn on the vacuum pump under the heat preservation state in step S2, extract the remaining air between the surface of the concave die body (13) and the plexiglass to form a negative pressure, ensure that the transparent part is completely attached to the surface of the concave die body (13), and keep the pressure for 2h - 3h and then cool down; S4: Cooling and taking out the part: Cool the temperature in the oven to room temperature while the vacuum pump is on, then push out the forming tooling, remove the convex die body (21) through a crane, and remove the formed ultra-thick double-curved plexiglass transparent part to complete the forming process.

2. The forming method of a super-thick double-curved plexiglass according to claim 1, characterized in that, Two groups of guide rods (18) are further arranged at both ends of the female die mold base (1), and the guide rods (18) are in guiding connection with the male die mold base (2).

3. The forming method of an ultra-thick double-curved plexiglass according to claim 1, characterized in that, The female die body (13) is positioned on the female die mold base (1) through a plurality of partition reinforcing ribs I (19), and the male die body (21) is positioned on the male die mold base (2) through a plurality of partition reinforcing ribs II (22).

4. A forming method for a super-thick double-curved plexiglass according to claim 3, characterized in that, The partition reinforcing ribs I (19) and the partition reinforcing ribs II (22) are distributed in a pairwise up-and-down opposite manner.

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