Environment-friendly stadium seat and metal plate heat transfer printing forming process thereof

Abstract

The invention discloses an environment-friendly stadium seat and a metal plate heat transfer printing forming process thereof. The environment-friendly stadium seat and the metal plate heat transfer printing forming process are suitable for public stadiums such as report halls and theaters. The seat comprises standing feet, a seat body and a leaning body, the seat body and the leaning body are both designed in a mode that an inner lining plate (a stress component) and an outer decorative plate (a decorative component) are separated, the inner lining plate is of a composite structure of a multi-layer plate and a steel frame and bears main loads, the outer decorative plate is an aluminum alloy plate or a cold-roll steel plate which is 1.5-3 mm thick, and the outer decorative plate is processed through a high-temperature wood grain heat transfer printing technology after being processed through stamping, welding and the like. The seat body is provided with high-density polyurethane shaping sponge and flame-retardant wear-resistant environment-friendly fabric, the backrest body is provided with a turnover mechanism which can be folded and stored, and the outer decorative plate is detachably connected with the inner lining plate. The metal plate heat transfer printing process comprises the steps of material selection, cutting, stamping, welding, polishing, pretreatment, plastic powder spraying and curing, high-temperature heat transfer printing and cooling demolding, and parameters are accurate and controllable. Formaldehyde release is completely eradicated, the structure is stable, the appearance is vivid, wear resistance and fire prevention are achieved, the service life is prolonged by 30% or above, the production efficiency is improved by 40%, and environment friendliness and practicability are both considered.

Description

Technical Field

[0001] This invention relates to the field of public seating manufacturing technology, specifically to an environmentally friendly seat suitable for public venues such as lecture halls, theaters, multi-purpose halls, auditoriums, and conference rooms, and the processing technology of its core components. Background Technology

[0002] In public venues such as lecture halls, theaters, and multi-purpose halls, seating serves as a core infrastructure, requiring simultaneous fulfillment of multiple demands regarding structural stability, environmental safety, and aesthetic appeal. Current technology commonly employs an integrated design where the outer panel is fixed to bear the load. This means the outer panel serves both decorative and load-bearing functions, making it prone to deformation, cracking, and other damage, severely impacting the seat's lifespan. Furthermore, the existing seat and backrest panels are often treated with paint, which continuously releases volatile harmful substances like formaldehyde and benzene, polluting the indoor environment and posing health risks to users, failing to meet the environmental requirements of modern public venues. In addition, traditional painting processes are cumbersome, offer limited color options, produce poor surface texture, and lack sufficient wear and scratch resistance, making it difficult to meet the high standards of public venues for both aesthetic appeal and durability.

[0003] Furthermore, while some existing technologies use electroplating or powder coating instead of painting for the metal outer panels of venue seats, electroplating carries the risk of heavy metal (such as chromium and nickel) pollution, incurs high wastewater treatment costs, and the plating layer is prone to oxidation and peeling. Powder coating suffers from poor adhesion and low coverage at edges and corners, easily leading to paint peeling and exposing the substrate after long-term use, significantly increasing maintenance costs. Meanwhile, the inner lining structure of traditional seats is mostly a single multi-layer board without reinforcing steel frames, making them prone to bending and deformation under long-term, high-frequency use, resulting in a loose overall seat structure and posing safety hazards. In addition, public venue seats have stringent fire resistance requirements; existing painting or powder coating processes often only achieve a fire resistance rating of GB 8624-2012C, which is insufficient to meet the fire safety standards of densely populated areas. Moreover, traditional molded foam often uses low-density polyurethane materials with poor resilience, showing significant collapse after 1-2 years of use, drastically reducing seating comfort and requiring frequent replacement, increasing venue operating costs.

[0004] Therefore, developing a venue seat that is structurally stable, environmentally friendly, aesthetically pleasing, durable, and meets fire safety requirements, along with its supporting processing technology, has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an environmentally friendly venue seat and its metal plate thermal transfer molding process. By optimizing the stress structure of the seat and innovating the surface treatment process, the seat achieves multiple technical effects such as "stable structure, environmentally friendly and formaldehyde-free, beautiful and durable", solving the problems of unreasonable stress, poor environmental performance and short service life of existing seats.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] An environmentally friendly venue seat includes a standing leg, a seat, and a backrest. Both the seat and backrest include an inner lining panel and an outer decorative panel. The outer decorative panel is a metal sheet that has been stamped, welded, and polished before being treated with a high-temperature wood grain heat transfer process. The inner lining panel is a load-bearing component, supporting the main loads of the seat and backrest, while the outer decorative panel is a decorative component and does not bear the main loads. The seat releases no formaldehyde, meeting environmental protection requirements. The seat is suitable for auditoriums, theaters, multi-purpose halls, auditoriums, and conference rooms.

[0008] Preferably, the inner lining is a combination structure of multi-layer board and steel frame, wherein the steel frame is embedded inside the multi-layer board or fixed to the outside of the multi-layer board.

[0009] Preferably, the metal plate is an aluminum alloy plate or a cold-rolled steel plate with a thickness of 1.5-3mm.

[0010] Preferably, the processing parameters of the high-temperature wood grain heat transfer process are: temperature 160-200℃, heat transfer time 15-30 minutes, and pressure 0.3-0.5MPa.

[0011] Preferably, the seat body further includes a molded sponge and a fabric. The molded sponge is attached to the outside of the inner lining plate, and the fabric is wrapped around the outside of the molded sponge. The fabric is a flame-retardant, wear-resistant, and environmentally friendly fabric, and the molded sponge is a high-density polyurethane sponge.

[0012] Preferably, the inner lining of the backrest is fixedly connected to a steel frame, and the steel frame is provided with a flipping mechanism, which is used to realize the folding and storage of the backrest.

[0013] Preferably, the outer decorative panel and the inner lining panel are detachably connected by clips or bolts.

[0014] Preferably, the feet are made of metal and formed by stamping, welding and grinding processes.

[0015] A heat transfer molding process for environmentally friendly stadium seating includes the following steps:

[0016] (1) Metal plate selection: Aluminum alloy plate or cold-rolled steel plate are selected;

[0017] (2) Cutting and blanking: CNC cutting equipment is used to precisely cut the metal plate;

[0018] (3) Stamping: The cut metal sheet is placed into a special mold and stamped into the prototype of the outer decorative panel by stamping equipment;

[0019] (4) Welding assembly: Argon arc welding is used to assemble the exterior decorative panel components that need to be spliced.

[0020] (5) Grinding: Use coarse sandpaper and fine sandpaper to grind the welded exterior decorative panel in turn to remove burrs, welding slag and surface defects.

[0021] (6) Surface pretreatment: Degreasing, oil removal and rust removal treatment of the polished exterior decorative panel;

[0022] (7) Powder coating and curing: The workpiece after surface pretreatment is subjected to particle grinding, then pretreatment spraying to remove dirt and oil, and then dried. After that, powder coating is applied and cured at 220℃ to form the first base color.

[0023] (8) High-temperature wood grain heat transfer: The cured exterior decorative board and wood grain paper are manually and tightly bonded together, and then placed in a heat transfer equipment and baked at about 170°C for 30 minutes to transfer the wood grain pattern on the wood grain paper to the surface of the metal plate to achieve the wood grain decorative effect.

[0024] (9) Cooling and demolding: After the heat transfer is completed, the material is allowed to cool naturally to room temperature. The remaining wood grain paper is then peeled off to obtain the finished outer decorative panel.

[0025] Preferably, the thickness of the metal plate in step (1) is 1.5-3mm; the stamping equipment in step (3) is a CNC stamping equipment with a stamping pressure of 100-150MPa; the argon arc welding current in step (4) is 80-120A; and the coarse sandpaper in step (5) is 80 mesh and the fine sandpaper is 200 mesh.

[0026] The beneficial effects of this invention are:

[0027] 1. Significantly improved structural stability: This invention adopts a separate design with an inner lining panel bearing the load and an outer decorative panel for decoration. The inner lining panel is reinforced with a multi-layer board + steel frame composite structure to enhance its load-bearing capacity, while the outer decorative panel is separated from the load-bearing load, avoiding deformation and damage caused by concentrated load, thus extending the service life of the seat by more than 30%.

[0028] 2. Environmental performance meets standards: The combination of powder coating and high-temperature wood grain heat transfer printing replaces traditional painting processes, completely eliminating the release of harmful substances such as formaldehyde and benzene. Formaldehyde release is tested to be ≤0.02mg / m³. 3The formaldehyde emission levels are far below the national standard GB 18587-2017 "Formaldehyde Emission Limits in Wood-based Panels and Their Products for Interior Decoration and Renovation", meeting the environmental protection requirements for public venues.

[0029] 3. Combining appearance and durability: The metal plate is powder coated to form a stable base color, and then heat transfer is used to form a natural and realistic wood grain effect, which is superior to traditional spray painting. At the same time, the surface of the metal plate forms a double-layer protective structure, with a wear resistance level of EN 317 standard level 4 or above, which is scratch-resistant, corrosion-resistant, and suitable for high-frequency use scenarios in public venues.

[0030] 4. High efficiency and energy saving: The combined process is reasonably designed, reducing multiple steps such as primer, topcoat and clear coat compared with the traditional spray painting process, increasing production efficiency by 40%, and eliminating spray painting exhaust emissions, which is environmentally friendly and energy-saving.

[0031] 5. High practicality: The seat structure is suitable for various public venues such as lecture halls and theaters. The backrest flipping mechanism can realize flexible use of space. The exterior decorative panel is detachable for easy maintenance and replacement. It has a wide range of applications. Attached Figure Description

[0032] Figure 1 This is a schematic diagram illustrating the implementation process of the metal plate heat transfer molding process for environmentally friendly stadium seats in this invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0034] This invention proposes an environmentally friendly stadium seat and its metal sheet thermal transfer molding process, characterized in that:

[0035] 1. Environmentally friendly venue seating structure

[0036] The environmentally friendly venue seating includes standing legs, a seat, and a backrest. These components work together to meet the usage needs of public venues.

[0037] The legs are made of high-strength metal (preferably aluminum alloy or cold-rolled steel plate), which are stamped and welded by molds and then polished to provide stable support for the entire seat and ensure that the seat does not tilt or wobble after installation.

[0038] The seat, from top to bottom, comprises fabric, molded foam, inner lining board, and outer decorative panel. The inner lining board is the core load-bearing component, employing a composite structure of multi-layer board and internal steel frame. The multi-layer board is made of environmentally friendly solid wood, and the steel frame is embedded inside the multi-layer board or fixed to the outside, forming a high-strength load-bearing skeleton to withstand the main load generated by the human body sitting on it. The outer decorative panel is a metal plate (1.5-3mm thick, aluminum alloy plate or cold-rolled steel plate are optional), serving only a decorative and protective function and not bearing the main load. It is detachably connected to the inner lining board by buckles or bolts for easy maintenance and replacement. The molded foam is made of high-density polyurethane material with excellent resilience, and the fabric is made of flame-retardant, wear-resistant, and environmentally friendly fabric that conforms to the human body's seating comfort requirements.

[0039] The backrest includes fabric, molded sponge, inner lining board, steel frame, flipping mechanism, and outer decorative panel; the inner lining board has the same structure as the seat's inner lining board, which is a multi-layer board + steel frame composite load-bearing structure, and is fixedly connected to the steel frame; the flipping mechanism is installed on the steel frame, which can realize the folding and storage of the backrest, saving venue space; the outer decorative panel has the same material and processing technology as the seat's outer decorative panel, which is a metal plate heat transfer part, and only serves a decorative function.

[0040] 2. Metal plate heat transfer molding process

[0041] The processing technology of the seat exterior trim panel includes the following steps:

[0042] (1) Metal plate selection: Select aluminum alloy plate or cold-rolled steel plate with a thickness of 1.5-3mm. This thickness range ensures the structural strength of the decorative plate and facilitates stamping.

[0043] (2) Cutting and blanking: According to the design dimensions of the outer decorative panel of the seat, a CNC laser cutting machine is used for precise cutting to ensure that the size error of the panel is ≤ ±0.5mm;

[0044] (3) Stamping: The cut metal sheet is placed into a special stamping die, and 100-150MPa pressure is applied by CNC stamping equipment to stamp and form an outer decorative panel prototype that matches the contour of the seat and backrest, ensuring that the sheet is free of wrinkles and cracks after forming.

[0045] (4) Welding assembly: For the external decorative panel components that need to be spliced ​​(such as the arc splicing part near the outer side panel), argon arc welding is used for welding assembly. The welding current is controlled at 80-120A to ensure that the weld is flat, without false welds, and without weld slag residue.

[0046] (5) Grinding process: rough grinding and fine grinding are carried out in sequence. Rough grinding uses 80-grit sandpaper to remove burrs and welding slag, and fine grinding uses 200-grit sandpaper to make the surface roughness Ra≤1.6μm of the board to ensure a smooth and flawless surface.

[0047] (6) Surface pretreatment: Place the polished metal plate into the degreasing tank and degrease it for 10-15 minutes at 50-60℃ with an alkaline degreasing agent (pH value 10-12). Then, wash and remove rust in sequence to remove surface oil and oxide layer and improve the adhesion between the subsequent plastic powder and the metal plate.

[0048] (7) Powder coating and curing: After surface pretreatment, the workpiece is subjected to particle grinding to further optimize the surface flatness; then, residual oil is removed by pretreatment spraying equipment, with the spraying pressure controlled at 0.2-0.3MPa and the spraying time at 5-8 minutes; after completion, it is sent to the drying oven and dried at 80-100℃ for 15-20 minutes to ensure that there is no moisture residue on the surface of the workpiece; then, the workpiece is coated with powder using electrostatic powder coating equipment. The powder is environmentally friendly polyester powder (free of heavy metals and volatile harmful substances), and the coating thickness is controlled at 60-80μm; after spraying, the workpiece is placed in the curing oven and cured at 220℃ for 20-25 minutes to form a uniform and dense first base color;

[0049] (8) High-temperature wood grain heat transfer: Use environmentally friendly wood grain paper (water-based environmentally friendly ink), and manually attach the wood grain paper to the surface of the cured exterior decorative board to ensure no bubbles or wrinkles; place the attached board into the heat transfer equipment, control the temperature at about 170℃ and the pressure at 0.3-0.5MPa, and bake for about 30 minutes to transfer the wood grain pattern on the wood grain paper evenly to the surface of the base color layer, so as to achieve a natural and realistic wood grain decorative effect.

[0050] (9) Cooling and demolding: After the heat transfer is completed, the metal plate is naturally cooled to room temperature, and the residual wood grain paper is peeled off to obtain a finished exterior decorative panel with a smooth surface, clear wood grain, and uniform base color.

[0051] (10) Assembly and molding: The molded sponge is attached and fixed to the outside of the inner lining board, wrapped with fabric and fixed with pressure strips. Then the outer decorative panel and the inner lining board are connected by buckles or bolts. Finally, the seat, backrest and legs are assembled and fixed to complete the production of the entire seat. Specific implementation examples:

[0053] The present invention will be further described in detail below with reference to specific embodiments:

[0054] Material Selection: The exterior decorative panel uses 2mm thick cold-rolled steel plate (material Q235, yield strength ≥235MPa) to ensure that the decorative panel has both rigidity and toughness; the inner lining panel uses 18mm thick environmentally friendly solid wood multilayer board (base material is poplar wood core, glue is formaldehyde-free soybean glue) + 3mm thick cold-rolled steel frame (steel frame cross-section size is 20mm×40mm, laser cutting is used for cutting), the multilayer board and steel frame are fixed with self-tapping screws (specification M4×16mm) to form a composite load-bearing structure; the shaping sponge uses 35 density high-resilience polyurethane sponge (resilience rate ≥70%, compression set ≤5%) to ensure that it will not collapse after long-term use; the fabric uses flame-retardant linen fabric (tested by GB 8624-2012 to meet the B1 fire resistance standard, Martindale abrasion resistance ≥50,000 times), taking into account both safety and durability;

[0055] Metal sheet processing: Cold-rolled steel sheets are cut according to the design dimensions (420mm×410mm for the seat exterior decorative panel and 520mm×760mm for the backrest exterior decorative panel) using a CNC laser cutting machine (1000W power, 500mm / min cutting speed), with cutting accuracy controlled within ±0.3mm; the cut steel sheets are then placed into a special stamping die (die material is Cr12MoV, surface hardness HRC). 58-62) The outer decorative panel prototype was stamped into shape using a CNC stamping machine (model J21-100, stamping pressure 120MPa, stamping speed 10 times / min). After stamping, an endoscope was used to check for cracks inside the panel. The curved joints of the body decorative panel (joint gap ≤0.5mm) were welded by argon arc welding (welding machine model WS-200, welding current 100A, argon flow rate 8L / min). After welding, the surface slag was removed with a wire brush, and then the burrs were removed by rough grinding with 80-grit alumina sandpaper (grinding speed 300r / min) and fine grinding with 200-grit silicon carbide sandpaper (grinding speed 500r / min). Finally, the surface roughness Ra of the panel was ≤1.6μm, which was confirmed by on-site testing with a surface roughness meter.

[0056] Surface pretreatment: The polished metal sheet is placed in a degreasing tank (tank material is 304 stainless steel, volume is 500L). The degreasing agent is a 5% concentration of sodium hydroxide and sodium carbonate mixed solution (mass ratio 1:1). The temperature is controlled at 55℃ and the degreasing time is 12 minutes. During this time, the sheet is continuously stirred with a stirrer (speed 60r / min) to ensure that the oil stains are completely removed. After degreasing, the sheet is transferred to a water washing tank for 3 water washes, each wash lasting 5 minutes, at room temperature. After water washing, the surface moisture is dried with compressed air (pressure 0.6MPa). Then, the sheet is placed in a rust removal tank and rust is removed for 5 minutes with an 8% concentration of phosphoric acid solution (temperature 40℃) to remove the surface oxide layer. After rust removal, the sheet is washed 3 more times, each time for 5 minutes. Finally, the sheet is placed in a drying oven (temperature 80℃, drying time 20 minutes) to dry, ensuring that there is no moisture residue on the surface of the metal sheet.

[0057] Powder Coating and Curing: The pre-treated workpiece undergoes particle polishing using 320-grit sandpaper, applied manually with uniform pressure to avoid scratching the surface. Residual oil and dirt are then removed using a pre-treatment spraying system (model PL-800) at a pressure of 0.25 MPa for 6 minutes, using a neutral cleaning agent (pH 7-8). After completion, the workpiece is placed in a drying oven at 90℃ for 18 minutes. Subsequently, electrostatic powder coating is applied using a system (model KCI-800) with environmentally friendly polyester powder (brand: AkzoNobel, model: Interpon 610), maintaining a coating thickness of 70 μm. Following coating, the workpiece is placed in a curing oven (model GH-100) and cured at 220℃ for 22 minutes to form a uniform and dense base coat. The thickness is then checked using a coating thickness gauge to ensure compliance with requirements.

[0058] Heat transfer: Use environmentally friendly walnut wood grain paper with a thickness of 80g / ㎡ (the ink is water-based and environmentally friendly, free of harmful substances such as benzene and toluene). Manually adhere the wood grain paper tightly to the surface of the cured exterior decorative panel, gently smoothing it with a scraper to remove air bubbles and ensure complete adhesion between the wood grain paper and the base color layer. Place the adhered panel into a heat transfer machine (model HT-600, electric heating method), set the temperature to 170℃ and the pressure to 0.4MPa, and bake for 30 minutes. Monitor the equipment temperature and pressure in real time during the heat transfer process to avoid parameter fluctuations that could cause blurry transfer patterns. After heat transfer, remove the panel and place it on a cooling rack (made of aluminum alloy with ventilation holes) to cool naturally to room temperature (approximately 30 minutes). After cooling, gently peel off any remaining wood grain paper along the edges with a utility knife and check for completeness of the transfer pattern, ensuring there are no missed prints or ghosting.

[0059] Assembly and Testing: The polyurethane foam is assembled using an environmentally friendly spray adhesive (model XY-603, formaldehyde emission ≤0.01mg / m³). 3 The sponge is pasted onto the outside of the inner lining panel, with a bonding area of ​​≥95% between the sponge and the inner lining panel to avoid air pockets. The sponge is then wrapped in flame-retardant linen fabric, with double-stitched seams (10 stitches / inch) and secured to the inner lining panel using stainless steel strips (1mm thick, 15mm wide). The outer decorative panel is connected to the inner lining panel using four ABS engineering plastic clips (model K-08, load-bearing capacity ≥50N), with a clip installation position deviation ≤1mm. The seat, backrest, and legs (made of 3mm thick cold-rolled steel plate, stamped and welded) are connected with M5×10mm stainless steel bolts, with the bolt tightening torque controlled at 8N·m, confirmed using a torque wrench. After assembly, the seat undergoes multiple performance tests: formaldehyde emission is measured using a 1m³ / hm filter. 3 The result obtained by climate chamber method (temperature 23℃, relative humidity 45%, detection time 24 hours) was 0.015 mg / m³. 3It conforms to GB 18587-2017 standard; in the structural strength test, the seat was subjected to a 750N pressure for 1 hour with a deformation of 1.2mm, and the backrest was subjected to a 300N tensile force for 1 hour with no loosening or deformation; in the fire resistance test, the fabric combustion performance reached GB 8624-2012 B1 level with no open flame combustion; in the abrasion resistance test of the exterior decorative panel, it was tested by a Martindale abrasion tester and the abrasion resistance was ≥60,000 times, which meets the requirements for use in public venues.

[0060] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. An environmentally friendly venue seat, characterized in that: it comprises a standing foot, a seat body and a back body, the seat body and the back body each comprise an inner lining plate and an outer decorative plate; the outer decorative plate is a metal plate, which is processed by high-temperature wood grain heat transfer printing process after being punched, welded and polished; the inner lining plate is a force-bearing component, which bears the main load of the seat body and the back body, and the outer decorative plate is a decorative component, which does not bear the main load; the seat is free of formaldehyde release and meets the environmental protection requirements; and the seat is suitable for report halls, theaters, multi-purpose halls, auditoriums and conference rooms. The inner lining plate is a combined structure of a multi-layer plate and a steel frame, and the steel frame is embedded in the multi-layer plate or fixed to the outside of the multi-layer plate.

2. The environmentally friendly venue seat of claim 1, wherein: The metal plate is an aluminum alloy plate or a cold-rolled steel plate, and the thickness is 1.5-3 mm.

3. The environmentally friendly venue seat of claim 1, wherein: The processing parameters of the high-temperature wood grain heat transfer printing process are: temperature 160-200℃, heat transfer printing time 15-30 minutes, and pressure 0.3-0.5 MPa.

4. The environmentally friendly venue seat of claim 1, wherein: The seat body further comprises a shaped sponge and a fabric, the shaped sponge is attached to the outside of the inner lining plate, and the fabric is wrapped outside the shaped sponge; the fabric is a flame-retardant and wear-resistant environmentally friendly fabric, and the shaped sponge is a high-density polyurethane sponge.

5. The environmentally friendly venue seat of claim 1, wherein: The inner lining plate of the back body is fixedly connected with a steel frame, and the steel frame is provided with a turnover mechanism for folding and storing the back body.

6. The environmentally friendly venue seat of claim 1, wherein: The outer decorative plate and the inner lining plate are detachably connected by buckles or bolts.

7. The environmentally friendly venue seat of claim 1, wherein: The standing foot is made of metal and is formed by punching, welding and polishing processes.

8. The environmentally friendly venue seat of claim 1, wherein: It comprises the following steps:

9. An environmentally friendly metal plate heat transfer printing forming process for a venue seat, characterized in that, (1) Selecting a metal plate: selecting an aluminum alloy plate or a cold-rolled steel plate; (2) Cutting and blanking: precisely cutting the metal plate by using a numerical control cutting equipment; (3) Punching forming: placing the cut metal plate into a special mold and punching it into an outer decorative plate by a punching equipment; (4) Welding assembly: welding and assembling the outer decorative plate components to be spliced by argon arc welding; (5) Polishing: polishing the welded outer decorative plate by using coarse sandpaper and fine sandpaper in sequence to remove burrs, welding slag and surface defects; (6) Surface pretreatment: degreasing, oil removal and rust removal treatment of the polished outer decorative plate; (7) Plastic powder spraying and curing: particle polishing of the surface pretreated workpiece, then removing dirt oil by pre-treatment spraying, drying after completion, then plastic powder spraying, and curing at 220℃ after spraying to form the first base color; (8) High-temperature wood grain heat transfer printing: manually closely attaching the cured outer decorative plate to the wood grain paper, placing it into a heat transfer printing equipment, baking at about 170℃ for 30 minutes to transfer the wood grain pattern on the wood grain paper to the surface of the metal plate to achieve a wood grain decoration effect; (9) Cooling and demolding: naturally cooling to room temperature after heat transfer printing, peeling off the residual wood grain paper to obtain the finished outer decorative plate. In step (1), the thickness of the metal plate is 1.5-3 mm; in step (3), the punching equipment is a numerical control punching equipment, and the punching pressure is 100-150 MPa; in step (4), the argon arc welding current is 80-120 A; and in step (5), the grit of the coarse sandpaper is 80 mesh, and the grit of the fine sandpaper is 200 mesh.

10. The sheet metal heat transfer printing forming process of claim 9, wherein: ​

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