High-temperature forming vacuum sheath for forming sheet metal and sheet forming method

Abstract

The invention belongs to the technical field of plate vacuum hot forming, and particularly relates to a high-temperature forming vacuum sheath used for forming a metal plate and a plate forming method.The high-temperature forming vacuum sheath used for forming the metal plate comprises an inner-layer soft vacuum sheath body, an outer-layer soft vacuum sheath body, an outer-layer soft vacuum sheath body, an inner-layer soft vacuum sheath body and an outer-layer soft vacuum sheath body, and the hard sheath wraps the outer side of the inner-layer soft vacuum sheath. The plate forming method comprises the following steps that S1, the formed plate blank is placed in the cavity of the inner-layer soft vacuum sheath, and the cavity is sealed after being vacuumized; s2, the inner-layer soft vacuum sheath filled with the formed plate blank is placed in a hard sheath; s3, the hard sheath is placed in a hot press to be machined; and S4, after cooling, the formed component is separated from the inner-layer soft vacuum sheath and the hard sheath, and the formed metal part is obtained. According to the invention, the air exhaust cost can be reduced, the air exhaust quality is improved, and the vacuum hot-pressing forming cost of the plate blank is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of vacuum hot forming of sheet metal, and in particular relates to a high-temperature forming vacuum jacket for forming metal sheet metal and a sheet metal forming method. Background Art

[0002] Vacuum forming has become an important force in promoting industrial progress with its special performance and wide application fields. With the rapid development of the aviation industry, the demand for large-sized, small-batch high-temperature vacuum-formed parts made of metal sheets is increasing. How to build a high-temperature vacuum forming environment for large-sized metal sheets at low cost and high quality has become a key issue in the aviation industry.

[0003] In the forming process of large-size metal sheets, in order to reduce the springback of the sheets, a stress relaxation stage is required after the sheets are formed to improve the forming accuracy. The metal sheets need to be insulated during this stage. Since the insulation time is long, the sheets are severely oxidized. In order to improve the quality of the metal sheets and reduce the degree of oxidation during the insulation process, the metal sheets need to be moved to a vacuum environment for forming and insulation.

[0004] Commonly used vacuum forming methods in industry include vacuum hot pressing furnace and welding metal sleeve. Vacuum hot pressing furnace is mainly composed of furnace body, furnace door, heating and insulation and temperature measurement system, vacuum system, inflation system, water cooling system, control system, hydraulic system, etc. It can effectively ensure the vacuum environment during high-temperature forming process, but due to the scarcity of large-size vacuum hot pressing furnace equipment, it is difficult to call the equipment and the cost of opening the furnace is high, which greatly limits the vacuum forming of large-size metal sheets.

[0005] Although welding metal sheaths can effectively reduce the cost of vacuum forming, large-sized sheaths are difficult to weld and are prone to leakage. At the same time, the forming shape is limited and the deformation is too large, which makes it easy for the weld to crack and leak. It cannot effectively ensure the stability of the vacuum environment. It is generally used for forming and heat preservation of materials with low vacuum requirements.

[0006] In summary, how to provide a large-size metal sheet forming device with good vacuum environment stability and low cost has become an urgent problem to be solved. Therefore, we propose a high-temperature forming vacuum jacket and a sheet forming method for forming metal sheets to solve the above problems. Summary of the invention

[0007] The object of the present invention is to provide a high temperature forming vacuum bag for forming metal sheets and a sheet forming method to solve the above problems.

[0008] To achieve the above object, the present invention provides the following solutions:

[0009] High temperature forming vacuum bag for forming metal sheets, including:

[0010] An inner soft vacuum bag has a cavity inside for accommodating the formed blank, and the cavity is used to be connected to a vacuum pumping device, wherein the cavity is evacuated by the vacuum pumping device to form a vacuum environment in the cavity;

[0011] The hard bag is wrapped around the outer side of the inner soft vacuum bag.

[0012] Preferably, the inner soft vacuum bag comprises a placement copper foil, a placement composite hot melt adhesive film, a covering composite hot melt adhesive film and a covering copper foil arranged in sequence from top to bottom;

[0013] The placement copper foil is fixedly connected to the placement composite hot melt adhesive film, the covering copper foil is fixedly connected to the covering composite hot melt adhesive film, and the cavity is located between the placement composite hot melt adhesive film and the covering composite hot melt adhesive film;

[0014] The placement copper foil is fixed to the edge of the covering copper foil.

[0015] Preferably, the hard casing comprises a sealing cover plate on the hard casing, a bottom plate placed under the hard casing and a heat expansion casing fixing strip;

[0016] A receiving cavity for receiving the inner soft vacuum bag is formed between the upper sealing cover plate of the hard bag and the bottom plate placed under the hard bag. The size of the receiving cavity matches the inner soft vacuum bag. The heat expansion bag fixing strip is respectively interference fit with the upper sealing cover plate of the hard bag and the bottom plate placed under the hard bag. The heat expansion bag fixing strip is used to fix the upper sealing cover plate of the hard bag and the bottom plate placed under the hard bag.

[0017] Preferably, a forming blank placement groove is provided in the middle of the bottom plate under the hard package, the inner soft vacuum package is placed in the forming blank placement groove, and the size of the forming blank placement groove matches the size of the inner soft vacuum package;

[0018] The left and right sides of the bottom plate under the hard package are respectively provided with staggered sealing step grooves for sliding sealing of the sealing cover plate on the hard package;

[0019] A fixing strip single-port card slot is provided at the front end of the bottom plate placed under the hard sleeve along the sliding direction of the sealing cover plate on the hard sleeve, and the fixing strip single-port card slot is interference-fitted with one side of the fixing strip of the thermal expansion sleeve;

[0020] One end of the single-port slot of the fixing strip passes through the side wall of the bottom plate placed under the hard cover, and the other end of the single-port slot of the fixing strip cooperates with the limit position of the thermal expansion cover fixing strip. A through hole is connected between the single-port slot of the fixing strip and the limit position of the thermal expansion cover fixing strip, and the through hole is used for a push rod to pass through to push the thermal expansion cover fixing strip out of the single-port slot of the fixing strip.

[0021] A Z-shaped sealing step groove is provided at the tail end of the bottom plate placed under the hard casing along the sliding direction of the sealing cover plate on the hard casing, and the Z-shaped sealing step groove is used for sealing and limiting cooperation with the sealing cover plate on the hard casing.

[0022] Preferably, staggered sealing steps are provided on both sides of the sealing cover plate on the hard package for slidingly sealingly cooperating with the staggered sealing step grooves;

[0023] The front end of the upper sealing cover plate of the hard sleeve in the sliding direction is provided with an upper cover plate fixing groove, and the upper cover plate fixing groove is interference-fitted with the other side of the thermal expansion sleeve fixing strip;

[0024] A Z-shaped sealing step is provided at the rear end of the sealing cover plate on the hard package in the sliding direction, and the Z-shaped sealing step is in sealing and limiting cooperation with the Z-shaped sealing step groove.

[0025] A sheet forming method, using the above-mentioned high temperature forming vacuum bag for forming metal sheet, comprises the following steps:

[0026] S1, placing the formed board blank in the cavity of the inner soft vacuum bag, and sealing the cavity after evacuating the cavity;

[0027] S2, placing the inner soft vacuum bag containing the formed slab into the hard bag;

[0028] S3, placing the hard package in a hot press for processing;

[0029] S4. After cooling, the formed plate blank is separated from the inner soft vacuum jacket and the hard jacket to obtain a formed metal part.

[0030] Preferably, in S1, the upper surface of the formed blank is covered with an upper layer of insulating graphite paper, and the lower surface of the formed blank is covered with a lower layer of insulating graphite paper, and then placed in the cavity.

[0031] Preferably, in S1, a hot pressing sealing machine is first used to seal three sides of the inner soft vacuum bag, leaving an opening for placing the formed board blank; after the formed board blank is placed in the inner soft vacuum bag, a hot pressing sealing machine is used to seal the edge of the opening and leave a vacuum exhaust port compatible with a vacuum pump; the vacuum exhaust port is connected to the vacuum pump, and the vacuum pump is used to evacuate the cavity; after the vacuum degree meets the forming requirements, a hot pressing sealing machine is used to hot-press and seal the vacuum exhaust port from the inside to the outside of the cavity, and then the vacuum pump is disconnected.

[0032] Compared with the prior art, the present invention has the following advantages and technical effects:

[0033] When in use, the formed plate blank is placed in the cavity inside the inner soft vacuum bag, and the cavity is evacuated to form a vacuum environment. The inner soft vacuum bag serves as the first layer of vacuum environment to ensure the vacuum requirement of the formed plate blank during hot pressing and cooling, and avoids oxidation of the formed plate blank in contact with air during hot pressing and cooling. Compared with the traditional use of a vacuum hot press for sheet forming, the application of a double-layer composite vacuum bag can reduce the cost of evacuation and improve the quality of evacuation. The double-layer composite vacuum bag is easy to manufacture and can be used with a traditional hot press, thereby reducing the cost of vacuum hot pressing of the formed plate blank. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor:

[0035] Figure 1 It is a schematic diagram of the structure of the present invention;

[0036] Figure 2 It is an exploded diagram of the structural schematic diagram of the present invention;

[0037] Figure 3 This is an exploded view of the inner soft vacuum jacket structure of the present invention;

[0038] Figure 4 A top view of the hard casing structure of the present invention;

[0039] Figure 5 For the present invention Figure 4 Middle AA section structure diagram;

[0040] Figure 6 For the present invention Figure 4 Middle BB section structure diagram;

[0041] Figure 7 This is a longitudinal parameter design diagram of the outer hard fixed cover of the present invention;

[0042] Figure 8 For the present invention Figure 5 A partial enlarged view of point C in the middle;

[0043] Fig. 9 For the present invention Figure 5 A partial enlarged view of point D in the middle;

[0044] Fig.10 For the present invention Figure 6 A partial enlarged view of point E in the middle;

[0045] Among them, 1. upper isolation graphite paper; 2. formed board blank; 3. lower isolation graphite paper; 4. inner soft vacuum jacket; 5. sealing cover plate on hard jacket; 6. heat expansion jacket fixing strip; 7. bottom plate placed under hard jacket; 401. copper foil placed; 402. composite hot melt adhesive film placed; 403. composite hot melt adhesive film covered; 404. copper foil covered; 501. staggered sealing steps; 502. Z-shaped sealing steps; 503. upper cover plate fixing groove; 701. through hole; 702. single-mouth card slot of fixing strip; 703. formed board blank placement groove; 704. staggered sealing step groove; 705. Z-shaped sealing step groove; 706. single-opening fixing strip guide groove. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] Reference Figures 1 to 10 The present invention discloses a high temperature forming vacuum bag for forming metal sheets, comprising:

[0049] The inner soft vacuum bag 4 has a cavity for accommodating the formed board blank 2, and the cavity is used to be connected to a vacuum pumping device, wherein the cavity is evacuated by the vacuum pumping device to form a vacuum environment in the cavity;

[0050] The hard package is wrapped around the outer side of the inner soft vacuum package 4.

[0051] When in use, the formed plate blank 2 is placed in the cavity inside the inner soft vacuum bag 4, and the cavity is evacuated to form a vacuum environment. The inner soft vacuum bag 4 serves as the first layer of vacuum environment to ensure the vacuum requirement of the formed plate blank 2 during the hot pressing and cooling process, and avoids the formed plate blank 2 from contacting and oxidizing with air during the hot pressing and cooling process. Compared with the traditional use of a vacuum hot press for sheet forming, the application of the inner soft vacuum bag 4 can reduce the exhaust cost and improve the exhaust quality. The double-layer composite vacuum bag is easy to manufacture and can be used with a traditional hot press, thereby reducing the cost of vacuum hot pressing of the formed plate blank 2.

[0052] Further optimizing the scheme, the inner soft vacuum bag 4 includes a copper foil 401, a composite hot melt adhesive film 402, a composite hot melt adhesive film 403 and a copper foil 404 arranged in sequence from top to bottom;

[0053] The placement copper foil 401 is fixedly connected to the placement composite hot melt adhesive film 402, the covering copper foil 404 is fixedly connected to the covering composite hot melt adhesive film 403, and the cavity is located between the placement composite hot melt adhesive film 402 and the covering composite hot melt adhesive film 403;

[0054] The copper foil 401 is placed and fixed at the edge with the covering copper foil 404 .

[0055] Through the above arrangement, during the hot pressing process, the placed composite hot melt adhesive film 402 and the covered composite hot melt adhesive film 403 are melted by heat to fill the gap in the cavity formed by the placed copper foil 401 and the covered copper foil 404, thereby avoiding damage and leakage during the forming process, and greatly improving the stability of the vacuum sealing environment during the forming process.

[0056] Furthermore, the placement composite hot melt adhesive film 402 and the covering composite hot melt adhesive film 403 are preferably HR-8787 water glass composite hot melt adhesive film.

[0057] Furthermore, the design and preparation method of the inner soft vacuum bag 4 is as follows:

[0058] The inner soft vacuum bag 4 comprises two layers of copper foil and two layers of water glass composite hot melt adhesive film.

[0059] First, the placement copper foil 401 is fixed to the placement composite hot melt adhesive film 402, and the covering copper foil 404 is fixed to the covering composite hot melt adhesive film 403. The smaller placement copper foil 401 and the placement composite hot melt adhesive film 402 are used as the reference. The larger covering composite hot melt adhesive film 403 and the covering copper foil 404 are fixed to the smaller placement film according to the design steps by a hot pressing sealing machine according to the design size requirements. The first edge sealing leaves the placement opening of the formed board blank 2, and the remaining edges are sealed according to the designed size requirements. Edge sealing is performed. After the formed board blank 2 is placed in, the second edge sealing is performed. The second edge sealing process leaves an exhaust port that is compatible with the vacuum exhaust machine. The vacuum exhaust machine is used to evacuate the inner layer of the soft vacuum bag 4 of the second edge sealing. After the vacuum degree requirement is met, the third edge sealing is performed. The third edge sealing first uses a hot press sealing machine to seal the inside of the exhaust port close to the formed board blank 2. After that, while disconnecting the vacuum exhaust machine, the exhaust port is completely sealed from the inside to the outside to ensure the uniformity of the soft bag around after three sealings.

[0060] Further optimizing the scheme, the hard casing includes a sealing cover plate 5 on the hard casing, a bottom plate 7 placed under the hard casing, and a heat expansion casing fixing strip 6;

[0061] An accommodating cavity for accommodating the inner soft vacuum jacket 4 is formed between the upper sealing cover plate 5 of the hard jacket and the bottom plate 7 placed under the hard jacket. The size of the accommodating cavity matches the inner soft vacuum jacket 4. The thermal expansion jacket fixing strip 6 is respectively interference fit with the upper sealing cover plate 5 of the hard jacket and the bottom plate 7 placed under the hard jacket. The thermal expansion jacket fixing strip 6 is used to fix the upper sealing cover plate 5 of the hard jacket and the bottom plate 7 placed under the hard jacket.

[0062] Further optimization scheme, the bottom plate 7 under the hard package is provided with a forming blank placement groove 703 in the middle, the inner soft vacuum package 4 is placed in the forming blank placement groove 703, and the size of the forming blank placement groove 703 matches the size of the inner soft vacuum package 4;

[0063] The left and right sides of the bottom plate 7 placed under the hard package are respectively provided with staggered sealing step grooves 704 for sliding sealing of the sealing cover plate 5 on the hard package;

[0064] A fixing strip single-port card slot 702 is provided at the front end of the bottom plate 7 placed under the hard sleeve along the sliding direction of the sealing cover plate 5 on the hard sleeve. The fixing strip single-port card slot 702 is interference-fitted with one side of the thermal expansion sleeve fixing strip 6.

[0065] One end of the single-port card slot 702 of the fixing strip passes through the side wall of the bottom plate 7 placed under the hard sleeve, and the other end of the single-port card slot 702 of the fixing strip is limitedly matched with the thermal expansion sleeve fixing strip 6. The single-port card slot 702 of the fixing strip and the thermal expansion sleeve fixing strip 6 are connected at the limit position with a through hole 701, and the through hole 701 is used for the ejector rod to pass through to eject the thermal expansion sleeve fixing strip 6 from the single-port card slot 702 of the fixing strip.

[0066] A Z-shaped sealing step groove 705 is provided at the tail end of the bottom plate 7 placed under the hard cover along the sliding direction of the sealing cover plate 5 on the hard cover. The Z-shaped sealing step groove 705 is used for sealing and limiting cooperation with the sealing cover plate 5 on the hard cover.

[0067] Further optimizing the solution, staggered sealing steps 501 are provided on both sides of the sealing cover plate 5 on the hard package to cooperate with the staggered sealing step grooves 704 for sliding sealing;

[0068] The front end of the hard cover upper sealing cover plate 5 in the sliding direction is provided with an upper cover plate fixing groove 503, and the upper cover plate fixing groove 503 is interference fit with the other side of the thermal expansion cover fixing strip 6;

[0069] A Z-shaped sealing step 502 is provided at the rear end of the sealing cover plate 5 on the hard package in the sliding direction, and the Z-shaped sealing step 502 is matched with the Z-shaped sealing step groove 705 for sealing and limiting.

[0070] Furthermore, the bottom plate 7 placed under the hard sleeve and the sealing cover plate 5 on the hard sleeve are made of materials with the same or similar forming properties as the formed plate blank 2, so as to reduce the influence of the hard sleeve on the formed plate blank 2 during the forming process, and the heat expansion sleeve fixing strip 6 is made of a material with a slightly higher thermal expansion coefficient than the hard sleeve, and the heat expansion sleeve fixing strip 6 and the hard sleeve have an interference fit, which is convenient for the installation and removal of the heat expansion sleeve fixing strip 6. At the same time, during the heating and forming process, the expansion of the heat expansion sleeve fixing strip 6 can further squeeze the sealing edge of the inner soft vacuum sleeve 4 and the fixed edge of the bottom plate 7 placed under the hard sleeve and the sealing cover plate 5 on the hard sleeve, so as to improve the sealing of the inner soft vacuum sleeve 4 and the structural stability of the outer hard fixed sleeve during the forming process.

[0071] Furthermore, the bottom plate 7 placed under the hard package is provided with a forming plate blank placement groove 703 for placing the inner soft vacuum package 4 covering the forming plate blank 2, and staggered sealing step grooves 704 are provided on the left and right sides of the forming plate blank placement groove 703 for sealing and fixing the two sides of the inner soft vacuum package 4 in the direction of the exhaust port, and are used for the staggered sealing steps 501 set on both sides of the sealing cover plate 5 on the hard package to slide in, and Z-shaped sealing step grooves 705 and single-opening fixing strips are provided on the upper and lower sides of the forming plate blank placement groove 703, respectively. The guide groove 706 is used to seal the inner soft vacuum bag 4 and fix the sealing cover plate 5 on the hard bag. A fixing bar single-mouth card groove 702 is provided at the extended end of the single-opening fixing bar guide groove 706 to further fix the heat expansion bag fixing bar 6 to prevent the fixed heat expansion bag fixing bar 6 from shifting during the forming process. A through hole 701 is provided on the outer side of the fixing bar single-mouth card groove 702 as a fixing bar extraction mark to mark the position of the fixed heat expansion bag fixing bar 6 and facilitate the removal of the heat expansion bag fixing bar 6 after forming.

[0072] The upper sealing cover plate 5 of the hard casing and the bottom plate 7 placed under the hard casing are provided with staggered sealing steps 501, Z-shaped sealing steps 502 and upper cover plate fixing grooves 503 correspondingly. At the same time, an upper cover plate fixing groove 503 is opened on the upper sealing cover plate 5 of the hard casing. The upper cover plate fixing groove 503 and the single-opening fixing strip guide groove 706 are spliced ​​to form a mortise for placing the heat expansion casing fixing strip 6. The heat expansion casing fixing strip 6 serves as a tenon and is inserted into the mortise. The open end of the single-opening fixing strip guide groove 706 of the bottom plate is inserted into the mortise of the upper sealing cover plate 5 of the hard casing, so that the upper and lower cover plates are connected and fixed.

[0073] A sheet forming method, using the above-mentioned high temperature forming vacuum bag for forming metal sheet, comprises the following steps:

[0074] S1, placing the formed board blank 2 in the cavity of the inner soft vacuum bag 4, and sealing the cavity after evacuating the cavity;

[0075] S2, placing the inner soft vacuum bag 4 containing the formed board blank 2 in the hard bag;

[0076] S3, placing the hard package in a hot press for processing;

[0077] S4. After cooling, the formed plate blank 2 is separated from the inner soft vacuum jacket 4 and the hard jacket to obtain a formed metal part.

[0078] According to a further optimized solution, in S1, the upper surface of the formed plate blank 2 is covered with an upper insulating graphite paper 1, and the lower surface of the formed plate blank 2 is covered with a lower insulating graphite paper 3, and then placed in the cavity.

[0079] To further optimize the solution, in S1, first use a hot press sealing machine to seal the three sides of the inner soft vacuum bag 4, leaving an opening for placing the formed board 2. After placing the formed board 2 into the inner soft vacuum bag 4, use a hot press sealing machine to seal the edge of the opening and leave a vacuum exhaust port compatible with the vacuum pump. The vacuum exhaust port is connected to the vacuum pump, and the vacuum pump is used to evacuate the cavity. After the vacuum degree meets the forming requirements, use a hot press sealing machine to hot-press and seal the vacuum exhaust port from the inside to the outside of the cavity, and then disconnect the vacuum pump.

[0080] The production and working principle of high temperature forming vacuum encapsulation of large size metal sheets, taking a rectangular structure as an example, includes the following steps:

[0081] S101, the specific process of the first edge sealing of the inner soft vacuum bag 4 is as follows: overlap a large and a small HR-8787 water glass composite hot melt adhesive film of designed size, then place a copper foil of corresponding size on both sides, and fix three of the sealing edges according to the designed surrounding size position by a hot pressing sealing machine, leaving an opening for placing the plate;

[0082] S102, the second edge sealing of the inner soft vacuum encapsulation 4 is as follows: the formed plate blank 2 is covered with graphite paper to prevent the formed plate blank 2 from directly contacting the HR-8787 water glass composite hot melt adhesive film, and then the opening of the inner soft vacuum encapsulation 4 is sealed again using a hot press sealing machine, leaving a vacuum exhaust port adapted to the vacuum exhaust machine;

[0083] S103, the specific process of the third edge sealing of the inner soft vacuum bag 4 is to connect the vacuum exhaust port of the inner soft vacuum bag 4 to the vacuum exhaust machine, and when the vacuum degree meets the forming requirements, use a hot pressing sealing machine to hot press and seal one end of the inner soft vacuum bag 4 close to the forming plate blank 2, and then disconnect the vacuum exhaust machine, and completely hot press and seal the inner soft vacuum bag 4 from the inside to the outside along the vacuum exhaust port, squeeze out the air in the exhaust port while ensuring the consistency of the surrounding structure of the inner soft vacuum bag 4.

[0084] S201, the raised covering end of the inner soft vacuum jacket 4 that has completed three edge sealing is placed into the designed forming blank placement groove 703, and the flat placement end of the inner soft vacuum jacket 4 is fitted with the sealing groove of the bottom plate 7 placed under the hard jacket, and then a long scraper is used to scrape and fit the surrounding sealing edges of the inner soft vacuum jacket 4 with the staggered sealing step groove 704, Z-shaped sealing step groove 705, and single-opening fixed strip guide groove 706 of the outer hard jacket, so as to facilitate the placement and pressing of the sealing cover plate 5 on the hard jacket;

[0085] S202, slowly push the upper sealing cover plate 5 of the hard sleeve along the staggered sealing step groove 704 of the bottom plate 7 placed under the hard sleeve to ensure the uniform discharge of the gas of the outer hard sleeve and the extrusion fit with the inner soft vacuum sleeve 4, and then insert the heat expansion sleeve fixing strip 6 into the mortise of the upper sealing cover plate 5 of the hard sleeve through the single-opening fixing strip guide groove 706, the tenon fits with the upper sealing cover plate 5 of the hard sleeve, and the tenon shoulder fits with the single-opening slot 702 of the fixing strip and the insertion end of the single-opening fixing strip guide groove 706, so that the upper and lower cover plates are connected and fixed.

[0086] S301, place the prepared high-temperature forming vacuum sheath of large-sized metal sheet in large-sized hot forming equipment. During the heating process of the high-temperature forming vacuum sheath of large-sized metal sheet in the equipment, the heat expansion sheath fixing strip 6 expands due to the heat and fixes the sealing cover plate 5 on the hard sheath and the bottom plate 7 under the hard sheath more tightly together. At the same time, the HR-8787 water glass composite hot melt adhesive film in the soft vacuum sheath is heated. While the HR-8787 water glass ensures the stable connection of the inner soft vacuum sheath 4, part of the internal composite components melt and soften, and flow to fill every corner of the inner soft vacuum sheath 4, thereby ensuring the stability of the vacuum environment during the high-temperature forming process.

[0087] S302, in the common mold bending and rolling extension forming process, the sealing ends of the sealing cover plate 5 on the hard sleeve and the bottom plate 7 placed under the hard sleeve will be continuously squeezed and fitted, which can further enhance the sealing stability of the inner soft vacuum sleeve 4 on all sides. At the same time, the composite components of the internal HR-8787 water glass composite hot melt adhesive film that are partially melted by heat can also flow in time under the action of extrusion to fill the gaps with smaller extrusion pressure, thereby stably ensuring the airtightness of the overall structure.

[0088] S401, after the hot forming of the formed plate blank 2 is completed, the high-temperature formed vacuum sheath of the large-sized metal plate will be re-solidified during the overall cooling process. The solidified components can better fit the plate blank and the surrounding of the sheath, effectively ensuring the airtightness during the cooling process. At the same time, the heat expansion sheath fixing strip 6 will also cool and shrink. After the forming is completed, an iron nail is used to knock and insert it from the through hole 701, and the heat expansion sheath fixing strip 6 can be pushed out from the other end to a certain length. After that, the heat expansion sheath fixing strip 6 can be pulled out. After the upper and lower hard sheaths are separated, the inner soft vacuum sheath 4 is taken out, and it is cut along the junction of the soft sheath covering surface and the plate blank placement surface to take out the high-temperature vacuum formed product after vacuum thermoforming wrapped with graphite paper.

[0089] Furthermore, the dimension design method of the inner soft vacuum bag 4 comprises the following steps:

[0090] The first step is to place the single-side dimensions of the copper foil 401 and the composite hot melt adhesive film 402. The composition includes staggered sealing sections , Deformation reserved segment , and the length of the plate blank L. Among them, the staggered sealing section In the middle, two horizontal sealing sections as well as According to design experience, 0.5H~2H is taken, where H is the thickness of the blank. At the same time, in order to reduce the influence of the package on the blank forming, the sealing structure dimensions of the left and right ends of the inner soft vacuum package 4 should be arranged symmetrically, and the staggered sections should be The value should be 0.5H, so that the sealing section of the inner soft vacuum jacket 4 is located at the bottom surface of the board embryo and the neutral layer of the board embryo respectively, so the total value range of the staggered sealing section at both ends is 3H~9H. The design is carried out according to the simulation results of abaqus and the sheet metal analysis of NX, where rolling is the length and thickness change value before and after deformation, and bending forming is the dimension extension value before and after deformation. At the same time, corrections are made based on actual experience, and the error estimate of the sheet thickness H is reserved on both sides. According to the above design method, the single-side dimensions for placing copper foil 401 and placing composite hot melt adhesive film 402 are finally designed as follows:

[0091] ;

[0092] The second step is to cover the composite hot melt adhesive film 403 and the single side size of the copper foil 404. The single-side dimensions of the copper foil 401 and the composite hot melt adhesive film 402 are On the basis of, two more board blank thickness H, so the single side size of the covering composite hot melt adhesive film 403 and the covering copper foil 404 is designed to be

[0093] ;

[0094] The third step is to determine the relevant dimensions of the cover layer and the placement layer, and use one side as the reference to hot press the staggered sealing section. Then, copper foil 401 and composite hot melt adhesive film 402 are placed to leave a blank placement section and a deformation reserved section. , covering the composite hot melt adhesive film 403 and covering the copper foil 404 to leave the corresponding blank covering section and deformation reserved section , and then according to the reserved size, the other section is hot-pressed from the inside to form the inner soft vacuum bag 4 in one direction to complete the size design and fixation, and the size design of the non-vacuum pumping end in the other direction is similar to the previous size determination step, and the size of the vacuum pumping end is determined according to the existing vacuum pumping machine. After the vacuum pumping is completed, further cutting is performed according to the size of the bag to complete the design of the inner soft vacuum bag 4.

[0095] Furthermore, the outer hard fixed package size design method includes the following steps:

[0096] The first step is that in the thickness direction, the maximum thickness of the outer hard fixed package after assembly is 3H, wherein at the placement position of the formed plate, the thickness of the placement bottom plate 7 under the hard package is H, the thickness of the formed plate blank placement groove is H, and the thickness of the cover plate of the sealing cover plate 5 on the hard package is H. In order to ensure the uniformity and reliability of the formed plate blank after being integrally formed with the package, the design always ensures that the neutral layer of the plate blank is located in the middle layer of the package thickness. At the same time, the thickness of the thermal expansion package fixing strip is designed to be H, and the lower end face of the single-opening fixing strip guide groove 706 is also arranged at the neutral layer of the plate blank to reduce interference with the plate blank forming process.

[0097] In the second step, in the width direction, the separation dimension n between the formed slab and the fixing strip is 0.5H to 1.5H to avoid the interference of the fixing strip on the deformation of the slab. At the same time, the width of the heat expansion sleeve fixing strip 6 is designed to be 1.5H, and the matching mode with the outer hard sleeve is transition matching, and the connection mode is mortise and tenon connection, which is convenient for the installation and removal of the heat expansion sleeve fixing strip 6, and at the same time ensures that the outer hard fixing sleeve can be better fixed during the heating and forming process. The distance of the Z-shaped sealing section is designed in combination with the sleeve fixing section f of the outer hard sleeve. At the same time, the outer width m of the sleeve should maintain consistency all around, and ensure To ensure the overall strength of the package.

[0098] The third step is to keep the middle working section of the package consistent with the soft package design in the length direction, and take the outer width as m, while ensuring that the overall design detail dimensions of the package are consistent in the width and length directions.

[0099] The fourth step is that the position of the fixing strip extraction mark should be consistent with the position of the thermal expansion sleeve fixing strip. At the same time, the width is about 0.5H. There is no strict design size requirement. It is sufficient to ensure that the positioning size is accurate and avoid interference with the internal board blank.

[0100] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., 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 do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0101] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A high temperature forming vacuum jacket for forming metal sheets, characterized in that: include: An inner soft vacuum bag (4) is provided with a cavity for accommodating the formed board blank (2), wherein the cavity is connected to a vacuum pumping device, wherein the cavity is evacuated by the vacuum pumping device so that a vacuum environment is formed in the cavity; The hard casing is wrapped around the outer side of the inner soft vacuum casing (4).

2. The high temperature forming vacuum bag for forming metal sheets according to claim 1, characterized in that: The inner soft vacuum bag (4) comprises a placement copper foil (401), a placement composite hot melt adhesive film (402), a covering composite hot melt adhesive film (403) and a covering copper foil (404) arranged in sequence from top to bottom; The placement copper foil (401) is fixedly connected to the placement composite hot melt adhesive film (402), the covering copper foil (404) is fixedly connected to the covering composite hot melt adhesive film (403), and the cavity is located between the placement composite hot melt adhesive film (402) and the covering composite hot melt adhesive film (403); The placement copper foil (401) and the covering copper foil (404) are fixed at their edges.

3. The high temperature forming vacuum bag for forming metal sheets according to claim 1, characterized in that: The hard casing comprises a sealing cover plate (5) on the hard casing, a bottom plate (7) placed under the hard casing, and a heat expansion casing fixing strip (6); A receiving cavity for receiving the inner soft vacuum jacket (4) is formed between the upper sealing cover plate (5) of the hard jacket and the lower base plate (7) of the hard jacket. The size of the receiving cavity matches that of the inner soft vacuum jacket (4). The heat expansion jacket fixing strip (6) is respectively interference-fitted with the upper sealing cover plate (5) of the hard jacket and the lower base plate (7) of the hard jacket. The heat expansion jacket fixing strip (6) is used to fix the upper sealing cover plate (5) of the hard jacket and the lower base plate (7) of the hard jacket.

4. The high temperature forming vacuum bag for forming metal sheets according to claim 3, characterized in that: A forming blank placement groove (703) is provided in the middle of the bottom plate (7) placed under the hard casing, and the inner soft vacuum casing (4) is placed in the forming blank placement groove (703), and the size of the forming blank placement groove (703) matches the size of the inner soft vacuum casing (4); The left and right sides of the bottom plate (7) placed under the hard casing are respectively provided with staggered sealing step grooves (704) for sliding sealing of the sealing cover plate (5) on the hard casing; A fixing strip single-port card slot (702) is provided at the front end of the bottom plate (7) placed under the hard sleeve along the sliding direction of the sealing cover plate (5) on the hard sleeve, and the fixing strip single-port card slot (702) is interference-fitted with one side of the thermal expansion sleeve fixing strip (6); One end of the fixing strip single-port slot (702) passes through the side wall of the bottom plate (7) placed under the hard sleeve, and the other end of the fixing strip single-port slot (702) cooperates with the thermal expansion sleeve fixing strip (6) in a limiting position. A through hole (701) is connected between the fixing strip single-port slot (702) and the thermal expansion sleeve fixing strip (6) in a limiting position, and the through hole (701) is used for a push rod to pass through to push the thermal expansion sleeve fixing strip (6) out of the fixing strip single-port slot (702); A Z-shaped sealing step groove (705) is provided at the rear end of the bottom plate (7) placed under the hard casing along the sliding direction of the sealing cover plate (5) on the hard casing, and the Z-shaped sealing step groove (705) is used for sealing and limiting cooperation with the sealing cover plate (5) on the hard casing.

5. The high temperature forming vacuum bag for forming metal sheets according to claim 4, characterized in that: Both sides of the sealing cover plate (5) on the hard casing are provided with staggered sealing steps (501) which cooperate with the staggered sealing step grooves (704) in a sliding and sealing manner; An upper cover plate fixing groove (503) is provided at the front end of the upper sealing cover plate (5) of the hard sleeve in the sliding direction, and the upper cover plate fixing groove (503) is interference-fitted with the other side of the thermal expansion sleeve fixing strip (6); A Z-shaped sealing step (502) is provided at the rear end of the sealing cover plate (5) on the hard casing in the sliding direction, and the Z-shaped sealing step (502) is in sealing and limiting cooperation with the Z-shaped sealing step groove (705).

6. A sheet forming method, using the high temperature forming vacuum bag for forming metal sheets according to any one of claims 1 to 5, characterized in that: The steps include: S1, placing the formed board blank (2) in the cavity of the inner soft vacuum bag (4), and sealing the cavity after evacuating the cavity; S2, placing the inner soft vacuum bag (4) containing the formed slab (2) inside the hard bag; S3, placing the hard package in a hot press for processing; S4, after cooling, separating the formed plate blank (2) from the inner soft vacuum jacket (4) and the hard jacket to obtain a formed metal part.

7. A sheet forming method according to claim 6, characterized in that: In S1, the upper surface of the formed plate blank (2) is covered with an upper layer of insulating graphite paper (1), and the lower surface of the formed plate blank (2) is covered with a lower layer of insulating graphite paper (3), and then placed in the cavity.

8. A sheet forming method according to claim 6, characterized in that: In S1, a hot press sealing machine is first used to seal three sides of the inner soft vacuum bag (4), leaving an opening for placing the formed blank (2). After the formed blank (2) is placed in the inner soft vacuum bag (4), a hot press sealing machine is used to seal the edge of the opening and leave a vacuum exhaust port compatible with a vacuum pump. The vacuum exhaust port is connected to the vacuum pump, and the vacuum pump is used to evacuate the cavity. After the vacuum degree meets the forming requirements, the hot press sealing machine is used to heat-press and seal the vacuum exhaust port from the inside of the cavity to the outside, and then the vacuum pump is disconnected.

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