Automated manufacturing method for formaldehyde-free moisture-proof plywood

Abstract

The present invention discloses an automated manufacturing method for formaldehyde-free moisture-proof plywood, comprising the following steps: pre-treatment of rotary-cut veneers; whole-sheet splicing of veneers; gluing: transporting whole-sheet veneers to a manipulator stack via a rail trolley, where the manipulator grabs the whole-sheet veneers on the manipulator stack one by one and places them on a gluing conveyor line, which delivers the whole-sheet veneers to a dual-fluid automatic atomizing gluing area for spraying with isocyanate adhesive; intelligent stacking of whole-sheet veneers; microwave preheating of slabs; continuous hot pressing of the slabs, followed by sawing, cooling, and curing to obtain core boards; gluing the surface of the core boards, which are then fed into a veneering device for laminating top and bottom surface boards, and then subjected to cold pressing, trimming, hot pressing, and polishing to obtain formaldehyde-free moisture-proof plywood. The method of the present invention can greatly improve the automation and scale of formaldehyde-free moisture-proof plywood production, effectively improve the product quality of the plywood, and increase production efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of plywood manufacturing, in particular to an automated manufacturing method for formaldehyde-free moisture-proof plywood. Background Art

[0002] Excessive formaldehyde levels in homes are a significant concern, with consumers viewing formaldehyde as public enemy number one. Consumers are increasingly seeking environmentally friendly, high-quality, and high-performance home products, leading to "formaldehyde-free" and "zero formaldehyde" becoming standard features for healthy and environmentally friendly homes. my country has also established a series of formaldehyde emission standards, such as GB / T 39600-2021 Formaldehyde Emission Classification for Artificial Boards and Their Products, the industry standard "Technical Requirements for Green Artificial Boards and Their Products" (LY / T2870-2017), and the currently revised group standard "Formaldehyde-Free Artificial Boards and Their Products" (T / CNFPIA3002-2018). The implementation of these standards regulates the production of formaldehyde-free / low-formaldehyde products. Among formaldehyde-free / low-formaldehyde artificial board products, plywood is the most widely used board, accounting for 2 / 3 of the total artificial board. It can be used for airplanes, ships, trains, cars, construction and packaging. It can be used not only in indoor furniture, bathroom toilets and balconies, but also in outdoor landscape gardens, parks, homestay cabins, exterior wall decoration and other scenes.

[0003] Most formaldehyde released from wood-based panels comes from adhesives. To meet market demands for green, environmentally friendly, and healthy products, adhesives used in plywood are being replaced with formaldehyde-free adhesives, water-based polyurethanes, and isocyanate adhesives made from biomass resources such as tannins, starch, lignin, and soy protein. However, the quality of boards produced with the first two adhesives is poor, primarily due to defects such as uneven bonding strength, susceptibility to cracking and deformation, poor stability, and mildew. Consequently, research on the use of isocyanate adhesives in plywood is increasing. However, the current automated production of formaldehyde-free, moisture-proof plywood using isocyanates still involves manual labor in many steps, such as manual gluing and stacking, resulting in low production efficiency. Furthermore, manual stacking after gluing can cause air to enter the adhesive between the boards after stacking, forming bubbles due to the curvature of the boards. These bubbles are difficult to expel, resulting in poor bonding and, in turn, uneven bonding strength. Therefore, it is very necessary to study a method for manufacturing formaldehyde-free moisture-proof plywood with a high degree of automation and the ability to ensure the strength of the plywood. Summary of the Invention

[0004] The present invention provides an automated manufacturing method for formaldehyde-free moisture-proof plywood, which can greatly improve the automation and scale level of formaldehyde-free moisture-proof plywood production, effectively improve the product quality of the plywood, and improve production efficiency.

[0005] To achieve the above object, the technical solution of the present invention is:

[0006] An automated manufacturing method for formaldehyde-free moisture-proof plywood comprises the following steps:

[0007] S1. Pretreatment of peeled veneer: Select one or two or more wood veneers from eucalyptus, birch, sycamore and poplar as peeled veneer, dry the veneer to a moisture content of 10-15%;

[0008] S2. Single-sheet splicing process: Splice the dried single sheets into a single sheet of the designed size and store them for later use;

[0009] S3. Gluing: A rail-mounted trolley transports the whole veneer sheets to the robotic stacking station. The robot, assembling the sheets in alternating horizontal and vertical directions, picks up the whole veneer sheets one by one and places them on the gluing conveyor line. The gluing conveyor line then delivers the whole veneer sheets to the dual-fluid automatic atomizing gluing area, where isocyanate adhesive and curing agent are sprayed.

[0010] S4. Intelligent stacking of whole veneer sheets: The automatic assembly head stacks the glued whole veneer sheets in alternating horizontal and vertical stacking to create the desired number of layers.

[0011] S5. Microwave preheating: The assembled slabs are heated by microwaves on the slab conveyor line, rapidly raising the temperature of the inner core of the slab to 50-60°C.

[0012] S6. Slab processing: The microwave-preheated slab is continuously hot-pressed, then sawn, cooled, and cured to obtain the core board.

[0013] S7. Glue is applied to the surface of the core board and sent to the veneering device to be attached to the top and bottom surface boards. After cold pressing, trimming, hot pressing and polishing, the formaldehyde-free moisture-proof plywood is obtained.

[0014] Furthermore, in step S3, the viscosity of the isocyanate adhesive is 150-250 mPa·s, the isocyanate content is 30.5-32%, and the density is 1.22-1.25 g / cm3.

[0015] Furthermore, in step S3, glue is applied in the dual-fluid automatic atomization gluing area using a single-sided gluing method. The isocyanate adhesive is transported to the continuous induction atomization spray rod through a closed channel, and after atomization, glue droplets are formed and glue is applied to the entire surface of the veneer. The glue application pressure of the continuous induction atomization spray rod is 5-10 Bar, the glue application temperature is 45-60°C, and the glue application amount is 25-50g / ㎡.

[0016] Furthermore, in step S5, the continuous hot pressing forming specifically includes: the microwave preheated slab is sequentially passed through a high-temperature pressurization zone, a high-temperature holding zone, a cooling and thickness setting zone, and a cooling and pressure reduction zone for continuous hot pressing, wherein the high-temperature pressurization zone is to increase the hot pressing temperature to T, and the hot pressing pressure is increased to F, and the high-pressure holding zone is to maintain the hot pressing temperature T and the hot pressing pressure F, wherein the hot pressing temperature T is 140-195°C, the hot pressing pressure F is 65-120N / ㎝2, the hot pressing speed is 50-300mm / s, and the hot pressing factor is 10-50s / mm, the cooling and thickness setting zone is to reduce the hot pressing temperature T to 130-(T-10)°C, and the cooling and pressure reduction zone is to reduce the temperature to below 100°C and the pressure to 60-80N / ㎝2.

[0017] Furthermore, in step S7, the veneer device includes a first conveyor, a second conveyor and a third conveyor with the same conveying direction, the first conveyor, the second conveyor and the third conveyor are arranged at intervals from top to bottom, and further include a first flip conveyor, a second flip conveyor and a limiting device, the loading end of the first flip conveyor is rotatably connected to the unloading end of the first conveyor, the unloading end is provided with a rotatable guide roller, the guide roller can move outward along the unloading end of the first flip conveyor, and a visual camera is provided below the first flip conveyor; the loading end of the second flip conveyor is rotatably connected to the unloading end of the second conveyor; the limiting device is slidably provided on the third conveyor, and a limiting plate is provided on the limiting device, and the direction of the limiting plate is opposite to the conveying direction of the third conveyor;

[0018] The laminating of the top surface plate and the bottom surface plate includes the following steps: the first conveyor, the second conveyor and the third conveyor respectively convey the top surface plate, the core plate and the bottom surface plate; when the bottom surface plate moves to the bottom of the unloading end of the second flip conveyor, the second flip conveyor flips downward, and the core plate moves downward along the second flip conveyor and is laminated from the front side of the bottom surface plate; at the same time, the limiting device moves to the front of the core plate and the bottom surface plate, and the limiting plate of the limiting device moves downward to block the front side of the core plate and the bottom surface plate, so that the front sides of the core plate and the bottom surface plate remain flush, and move forward with the core plate and the bottom surface plate; the first flip conveyor also flips downward, conveys the top surface plate to the core plate and laminates from the front side of the core plate; the limiting device remains in front of the top surface plate, core plate and bottom surface plate, so that the front sides of the top surface plate, core plate and bottom surface plate remain flush, and the rear limiting plate moves upward, so that the laminated top surface plate, core plate and bottom surface plate move along the third conveyor to the feed and discharge power rolling line, and then are conveyed to the cold press.

[0019] Furthermore, the veneer device also includes a fourth conveyor and a lifting conveyor, the unloading end of the fourth conveyor is connected to the loading end of the third conveyor, and the loading end of the fourth conveyor extends to the side of the third conveyor; the unloading end of the fourth conveyor is provided with a plurality of conveying rollers, the rotation axis of the conveying rollers is consistent with the conveying direction of the third conveyor, and the conveying rollers are arranged at equal intervals, and the height of the conveying surface of the fourth conveyor is lower than the height of the conveying surface of the third conveyor; the lifting conveyor includes a base, a lifting frame, a lifting drive assembly and a lifting pulley, the The base is fixedly installed below the unloading end of the fourth conveyor, one end of the lifting drive assembly is connected to the base, and the other end of the lifting drive assembly is connected to the lifting frame and can drive the lifting frame to rise and fall in the vertical direction; there are several groups of lifting pulleys, each group of the lifting pulleys is installed on the lifting frame at equal intervals, and the positions of the lifting pulleys are staggered with the positions of the conveying rollers, and a lifting conveyor belt is wrapped around the periphery of each group of the lifting pulleys. The conveying direction of the lifting conveyor belt is consistent with the conveying direction of the third conveyor, and each group of the lifting pulleys can operate synchronously.

[0020] Furthermore, the distance from the other end of the first overturning conveyor to the other end of the third conveyor is smaller than the distance from the other end of the second overturning conveyor to the other end of the third conveyor.

[0021] Furthermore, an introduction block is installed at the discharge end of the second flip conveyor, the bottom of the introduction block is provided with an arc surface, and the top of the introduction block is provided with a detachable nylon plate, and the top surface of the nylon plate is not higher than the conveying plane of the second flip conveyor.

[0022] Furthermore, the limiting device further includes a movable column and a movable beam, the movable columns having two in total, one end of each of the two movable columns being slidably mounted on the side of the third conveyor, and both ends of the movable beam being slidably connected to the side of one of the movable columns, and a plurality of limiting plates being installed on the movable beam at intervals, so that when the movable beam slides along the movable column, the limiting plates can be moved closer to or away from the conveying plane of the third conveyor;

[0023] The third conveyor is provided with a third conveyor belt, and the number of the third conveyor belts is several, and the third conveyor belts are arranged at equal intervals. When the limit plate approaches the conveying plane of the third conveyor, the bottom of the limit plate can extend into the area between the third conveyor belts.

[0024] Furthermore, the veneer device also includes a first hydraulic cylinder and a second hydraulic cylinder; the telescopic end of the first hydraulic cylinder is connected to the front bottom of the first flip conveyor, and the fixed end is fixed; the telescopic end of the second hydraulic cylinder is connected to the front bottom of the second flip conveyor, and the fixed end is fixed.

[0025] The automated manufacturing method for formaldehyde-free moisture-proof plywood described above has the following advantages:

[0026] (1) The present invention combines the use of a robot for automatic assembly, dual-fluid automatic atomization gluing, a conveyor line for conveying panels for stacking, microwave heating and continuous hot pressing, which greatly improves the degree of automation and scale of plywood production, effectively improves the product quality of plywood, increases production efficiency and reduces labor costs.

[0027] (2) The present invention uses isocyanate as an adhesive and is equipped with an automated manufacturing method for formaldehyde-free moisture-proof plywood suitable for isocyanate as an adhesive, which solves the "formaldehyde" problem from the source and ensures green, environmentally friendly and healthy production.

[0028] (3) The present invention further improves the laminating method of the top surface plate and the bottom surface plate. During laminating, the core plate is laminated from the front side to the back side of the bottom surface plate, and the top surface plate is laminated from the front side to the back side of the core plate, so that the air in the adhesive layer can be expelled from the back side during assembly to prevent the formation of bubbles. Compared with manual stacking, this can greatly reduce the number of bubbles in the adhesive between the core plate and the bottom surface plate, improve the bonding performance, better solve the problem of uneven bonding strength, ensure that the product is flat and uniform, and hassle-free pressing, while further improving the degree of automation of production.

[0029] (4) When assembling the top surface plate, the present invention locks the edge of the core plate through a visual camera, and then automatically adjusts the support position through a guide roller to adapt to the curvature of the surface plates of different materials, so that the edges of the top surface plates of different materials are automatically aligned when they are fitted together, thereby ensuring the quality of the assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural diagram of the veneer device of the present invention.

[0031] Figure 2 It is a structural diagram of the first overturning conveyor.

[0032] Figure 3 It is a structural diagram of the second turning conveyor.

[0033] Figure 4 It is a structural diagram of the limit device.

[0034] Figure 5 It is a structural diagram of the fourth conveyor and the lifting conveyor.

[0035] Explanation of main figure marks: 100-first conveyor; 200-second conveyor; 300-third conveyor, 310-third conveyor belt, 320-glue spraying mechanism, 330-collecting trough; 400-first flip conveyor, 410-guide roller, 420-first hydraulic cylinder; 500-second flip conveyor, 510-introduction block, 511-arc surface, 512-nylon plate, 520-second hydraulic cylinder; 600-limiting device, 610-limiting plate, 620-movable column, 630-moving beam; 700-visual camera; 800-fourth conveyor, 810-conveyor roller; 900-lifting conveyor, 910-base, 920-lifting frame, 930-lifting drive assembly, 940-lifting pulley. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0037] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "top", "bottom", "top surface", "bottom surface", "inside", "outside", "inside", "outside" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the 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 limiting the present invention.

[0038] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The terms "first," "second," and "third" are used solely for descriptive purposes and to distinguish technical features. They are not to be construed as indicating or implying relative importance, or as implicitly specifying the number or order of the technical features indicated.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified or limited, the terms "installed," "connected," "connected," and "set" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium, or they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances. The following describes an embodiment of the present invention based on its overall structure. Example 1

[0040] An automated method for manufacturing formaldehyde-free, moisture-proof plywood includes the following steps: S1. Pretreatment of peeled veneers: Selecting sycamore veneers as peeled veneers and drying them to control the moisture content of the veneers to within the range of 10-15%; S2. Splicing the veneers into whole sheets: Splicing the dried veneers into whole sheets of designed dimensions and storing them for future use; S3. Gluing: Using a rail trolley, the whole sheets are transported to a robotic stacking station. The robotic stacking station, in an alternating horizontal and vertical arrangement, picks up the whole sheets one by one and places them on a gluing conveyor line. The gluing conveyor line then delivers the whole sheets to a dual-fluid automatic atomizing gluing area for spraying with isocyanate adhesive and curing agent; S4. Intelligent stacking of whole veneer sheets: The automatic assembling head stacks the whole veneer sheets after gluing in an alternating horizontal and vertical manner to form 9 layers of slabs, among which birch and sycamore are stacked alternately; S5. Microwave preheating: The assembled slabs are passed through the slab conveyor line for microwave heating of the core, so that the temperature of the inner layer of the core of the slab is rapidly raised to 53-55°C; S6. Slab processing: The microwave-preheated slabs are continuously hot-pressed, and then sawed, cooled, and cured to obtain the core board; S7. Glue is applied to the surface of the core board and sent to the veneering device to be covered with the top and bottom surface boards. The top and bottom surface boards are made of mahogany veneer, which is cold-pressed, trimmed, hot-pressed, and polished to obtain formaldehyde-free moisture-proof plywood.

[0041] In step S3, the viscosity of the isocyanate adhesive is 225-230 mPa·s, the isocyanate content is 31.5-32%, and the density is 1.22-1.25 g / cm3.

[0042] In step S3, adhesive is applied in a dual-fluid automated atomization area using a single-sided adhesive application method. Isocyanate adhesive is delivered through a closed channel to a continuous induction atomization spray bar. Atomized adhesive droplets are applied across the entire surface of the veneer sheet. The continuous induction atomization spray bar applies adhesive at a pressure of 8-10 bar, a temperature of 45-47°C, and a quantity of 25g / m2. Using a closed channel to deliver the isocyanate adhesive prevents direct contact between operators and reduces its negative impact on the human body. Atomized adhesive droplets are applied across the entire surface of the veneer sheet, improving adhesive application uniformity and penetration, thereby enhancing bonding performance.

[0043] In step S5, continuous hot pressing forming specifically includes: the microwave preheated slab passes through the high-temperature boosting zone, the high-temperature holding zone, the cooling and thickness setting zone, and the cooling and pressure reduction zone for continuous hot pressing in sequence. The high-temperature boosting zone is to increase the hot pressing temperature to 182°C, and the hot pressing pressure is increased to 108N / ㎝2. The high-pressure holding zone is to maintain the hot pressing temperature at 182-185°C, the hot pressing pressure is 108-110N / ㎝2, the hot pressing speed is 90mm / s, and the hot pressing factor is 30.2s / mm. The cooling and thickness setting zone is to reduce the hot pressing temperature from 182-185°C to 130°C. The cooling and pressure reduction zone is to reduce the temperature to below 100°C and the pressure to 65N / ㎝2.

[0044] Furthermore, in step S7, combined with Figure 1-5 As shown, the veneering device includes a first conveyor 100, a second conveyor 200 and a third conveyor 300 with the same conveying direction. The first conveyor 100, the second conveyor 200 and the third conveyor 300 are arranged at intervals from top to bottom. The first conveyor 100, the second conveyor 200 and the third conveyor 300 are used to convey the top surface board, the core board and the bottom surface board respectively. The veneering device also includes a first flip conveyor 400, a second flip conveyor 500 and a limiting device 600. The loading end of the first flip conveyor 400 is connected to the first conveyor 1 00 is rotatably connected to the unloading end, and the unloading end is provided with a rotatable guide roller 410, which can move outward along the unloading end of the first flip conveyor 400, and a visual camera 700 is provided under the first flip conveyor 400; the loading end of the second flip conveyor 500 is rotatably connected to the unloading end of the second conveyor 200; the limiting device 600 is slidably provided on the third conveyor 300, and a limiting plate 610 is provided on the limiting device 600, and the direction of the limiting plate 610 is opposite to the conveying direction of the third conveyor 300.

[0045] The laminating process of the top surface plate and the bottom surface plate includes the following steps: the first conveyor 100, the second conveyor 200 and the third conveyor 300 respectively convey the top surface plate, the core plate and the bottom surface plate; when the bottom surface plate moves to the bottom of the unloading end of the second flip conveyor 500, the second flip conveyor 500 flips downward, and the core plate moves downward along the second flip conveyor 500 and is laminated from the front side of the bottom surface plate; at the same time, the limiting device 600 moves to the front of the core plate and the bottom surface plate, and the limiting plate 610 of the limiting device 600 moves downward to block the core plate and the bottom surface plate. The front side of the core plate and the bottom surface plate are kept flush, and the core plate and the bottom surface plate move forward together. The first flip conveyor 400 also flips downward, transports the top surface plate to the top of the core plate and fits it from the front side of the core plate. The limiting device 600 remains in front of the top surface plate, the core plate and the bottom surface plate, so that the front sides of the top surface plate, the core plate and the bottom surface plate are kept flush. The rear limiting plate 610 moves upward, so that the top surface plate, the core plate and the bottom surface plate that are fitted together follow the movement of the third conveyor 300 to the inlet and outlet power roller line, and then transported to the cold press. The core plate is fitted from the front side to the back side of the bottom surface plate, that is, pressed from one side to the other side, so that the air in the glue layer can be expelled from the back side during assembly to prevent the formation of bubbles. Compared with manual stacking, this can greatly reduce the bubbles in the adhesive between the core plate and the bottom surface plate, improve the bonding performance, and better solve the problem of uneven bonding strength. Similarly, the top surface plate is bonded from the front side to the back side of the core plate, so that the air in the glue layer can be driven out from the back side during assembly to prevent the formation of bubbles. In addition, a visual camera 700 is provided below the first flip conveyor 400, which cooperates with the first flip conveyor 400 and the guide roller 410 to align the edge of the top surface plate with the edge of the core plate. The visual camera can lock the edge of the core plate, and the guide roller 410 automatically adjusts the support position so that the top surface plate made of materials with different curvatures can fit the core plate as closely as possible. For example, for top surface plates with larger curvatures, the guide roller 410 needs to be extended forward to prevent it from sagging excessively and affecting the bonding effect. For top surface plates with smaller curvatures, they can rely more on their own strength to keep straight and fit the core plate. In combination with the position and speed of the core plate, the first flip conveyor 400 adjusts the appropriate rotation angle so that the top surface plate can control a reasonable walking speed. Ultimately, the top surface plates of different materials are automatically aligned with the edge of the core plate when bonded, ensuring the quality of the assembly. Regarding the automatic adjustment of the support position of the guide roller 410, a hydraulic cylinder or pneumatic cylinder can be provided to drive the guide roller 410 to extend and retract, thereby adjusting the curvature of the surface plate of different materials. The limit device 600 can be slidably provided on the third conveyor 300. This can be achieved by providing slide rails on both sides of the frame of the third conveyor 300, with a hydraulic cylinder or pneumatic cylinder installed at one end. The telescopic end of the hydraulic cylinder or cylinder is connected to the limit device 600, and the telescopic movement of the hydraulic cylinder or cylinder can drive the limit device 600 to slide back and forth.

[0046] Preferably, the technical solution of the above-mentioned veneer device further includes a fourth conveyor 800 and a lifting conveyor 900, wherein: the unloading end of the fourth conveyor 800 is docked with the loading end of the third conveyor 300, and the loading end of the fourth conveyor 800 extends to the side of the third conveyor 300. The unloading end of the fourth conveyor 800 is provided with a plurality of conveying rollers 810, and the rotation axis of the conveying rollers 810 is consistent with the conveying direction of the third conveyor 300; each conveying roller 810 is arranged at equal intervals, and the height of the conveying surface of the fourth conveyor 800 is lower than the height of the conveying surface of the third conveyor 300. Combined Figure 5 As shown, the lifting conveyor 900 includes a base 910, a lifting frame 920, a lifting drive assembly 930 and a lifting pulley 940; the base 910 is fixedly installed below the unloading end of the fourth conveyor 800, one end of the lifting drive assembly 930 is connected to the base 910, and the other end of the lifting drive assembly 930 is connected to the lifting frame 920 and can drive the lifting frame 920 to move up and down in the vertical direction. The lifting drive assembly 930 can adopt a variety of structures, such as a hydraulic cylinder, a pneumatic cylinder, or a motor-driven screw structure; there are several groups of lifting pulleys 940, each of which is installed on the lifting frame 920 at equal intervals, and the position of the lifting pulleys 940 is staggered with the position of the conveying roller 810. The lifting pulleys 940 are surrounded by a lifting conveyor belt, and the conveying direction of the lifting conveyor belt is consistent with the conveying direction of the third conveyor 300. The lifting pulleys 940 can operate synchronously, and the conveying surface of the lifting conveyor belt is the conveying surface of the unloading end of the fourth conveyor 800. In this embodiment, the loading end of the fourth conveyor 800 is extended to the side of the third conveyor 300, so that the fourth conveyor 800 and the third conveyor 300 form an L-shaped layout. A robot can be installed in the area enclosed by the third conveyor 300 and the fourth conveyor 800. The robot can conveniently load materials onto the first conveyor 100 and the fourth conveyor 800 at the same time, saving equipment installation space and improving the automation level of loading; the lifting conveyor 900 can make the conveying direction of the bottom surface plate on the fourth conveyor 800 achieve a 90-degree turn on the spot, so that the conveying direction of the bottom surface plate remains consistent with the conveying direction of the third conveyor 300, thereby further saving equipment installation space. The lifting conveyor 900 can change the height of the conveying surface of the unloading end of the fourth conveyor 800. When the bottom surface plate is transported to the location and needs to be transferred to the third conveyor 300, the height of the conveying surface of the unloading end of the fourth conveyor 800 is raised so that it is consistent with the height of the conveying surface of the third conveyor 300 or slightly higher than the conveying surface of the third conveyor 300, thereby transporting the bottom surface plate to the third conveyor 300 through the conveying roller 810.

[0047] Preferably, in the technical solution of the above-mentioned veneering device, the distance from the other end of the first flip conveyor 400 to the other end of the third conveyor 300 is smaller than the distance from the other end of the second flip conveyor 500 to the other end of the third conveyor 300. This allows the composite structure of the core board and the bottom surface board, and the top surface board and the core board and the bottom surface board to be sequentially bonded, thereby better ensuring the veneering quality.

[0048] Preferably, in the technical solution of the above-mentioned veneer device, an introduction block 510 is installed at the discharge end of the second flip conveyor 500. The bottom of the introduction block 510 is provided with a circular arc surface 511, and the top of the introduction block 510 is provided with a detachable nylon plate 512, and the top surface of the nylon plate 512 is not higher than the conveying plane of the second flip conveyor 500. Due to the provision of the introduction block 510 and the circular arc surface 511 at the bottom of the introduction block 510, the circular arc surface 511 can prevent the bottom surface plate from being scratched when the second flip conveyor 500 is flipped at the discharge end. The nylon plate 512 installed on the top of the introduction block 510 can prevent the bottom surface of the core plate from being scratched during discharge and can make the discharge of the core plate smoother.

[0049] Preferably, in the technical solution of the above-mentioned veneer device, Figure 4 As shown, the limiting device 600 also includes a movable column 620 and a movable beam 630. There are two movable columns 620. One end of the two movable columns 620 is respectively slidably mounted on the side of the third conveyor 300. The slidable mounting method can be that the columns are set in a slide rail and driven by a hydraulic cylinder or an air cylinder; the two ends of the movable beam 630 are respectively slidably connected to the side of a movable column 620. There are several limiting plates 610, and each limiting plate 610 is installed at intervals on the movable beam 630. When the movable beam 630 slides along the movable column 620, the limiting plate 610 can be moved closer to or away from the conveying plane of the third conveyor 300. When it is close to the conveying plane, it can block the plate, and when it is away from the conveying plane, it can allow the plate to pass smoothly. The third conveyor 300 is provided with a third conveyor belt 310. There are several third conveyor belts 310, and each third conveyor belt 310 is arranged at equal intervals. When the limiting plate 610 approaches the conveying plane of the third conveyor 300, the bottom of the limiting plate 610 can extend into the area between the third conveyor belts 310 to better keep the front sides of each layer of the plate flush when blocking the plate.

[0050] Preferably, in the technical solution of the above-mentioned laminating device, this embodiment provides a structure for driving the first flip conveyor 400 and the second flip conveyor 500 to rotate, combined with Figure 2 and Figure 3As shown, the veneer device also includes a first hydraulic cylinder 420 and a second hydraulic cylinder 520; the telescopic end of the first hydraulic cylinder 420 is connected to the front bottom of the first flip conveyor 400, and the fixed end is fixed. The fixed end can be fixed on the ground, or it can be fixed on the bottom of the frame of the first conveyor 100 or the second conveyor 200 or the third conveyor 300. At the same time, the loading end of the first flip conveyor 400 is rotatably connected to the unloading end of the first conveyor 100, and the rotation of the first flip conveyor 400 can be achieved by extending or shortening the first hydraulic cylinder 420; the telescopic end of the second hydraulic cylinder 520 is connected to the front bottom of the second flip conveyor 500, and the fixed end is fixed. The fixed end can be fixed on the ground, or it can be fixed on the bottom of the frame of the second conveyor 200 or the third conveyor 300. Similarly, the rotation of the second flip conveyor 500 can be achieved by extending or shortening the second hydraulic cylinder 520. There are many options for the rotational connection between the loading end of the first flip conveyor 400 and the unloading end of the first conveyor 100, and the rotational connection between the loading end of the second flip conveyor 500 and the unloading end of the second conveyor 200. The most convenient installation method is the shaft rotation connection method.

[0051] In addition, the veneer needs to be coated with adhesive. For the core board, the adhesive can be applied to the core board surface in advance using a glue roller. For the bottom surface board, the adhesive can be applied to the core board surface in advance using a glue roller. Alternatively, a glue spraying mechanism 320 can be installed in the veneer device. Figure 1 As shown, a glue spraying mechanism 320 is provided above the third conveyor 300, which needs to spray glue before laminating with the core board. Below the third conveyor 300, corresponding to the position of the glue spraying mechanism 320, a collection tank 330 is provided. If the adhesive exceeds the area of ​​the bottom surface board during spraying, it can be recovered through the collection tank 330.

[0052] After the top surface board, core board and bottom surface board are pasted, the subsequent cold pressing, trimming, hot pressing, polishing and other processes can be operated by referring to the "A method for manufacturing fully automatic and fast formaldehyde-free pressed veneer plywood" disclosed in CN114833902A. Example 2

[0053] The second embodiment is basically the same as the first embodiment, but with the following substitutions:

[0054] In step S1, eucalyptus wood veneer is selected as the peeled veneer; in step S3, the viscosity of the isocyanate adhesive is 200-202 mPa·s, the isocyanate content is 30.5-31%, and the density is 1.22-1.25 g / cm3; the pressure of the continuous induction atomization spray rod for gluing is 6-8 Bar, the gluing temperature is 58-60°C, and the gluing amount is 40 g / ㎡; in step S5, microwave heating is used to quickly raise the temperature of the inner layer of the core of the slab to 58- 60℃; the high temperature and pressure rising zone is to increase the hot pressing temperature to 192℃, and the hot pressing pressure is increased to 118N / ㎝2; the high pressure insulation zone is to maintain the hot pressing temperature at 192-195℃, the hot pressing pressure is 118-120N / ㎝2, the hot pressing speed is 110mm / s, and the hot pressing factor is 25.5s / mm; the cooling and thickness setting zone is to reduce the hot pressing temperature from 192-195℃ to 140℃; the cooling and pressure reduction zone is to reduce the temperature to below 100℃ and the pressure to 70N / ㎝2. Example 3

[0055] The third embodiment is basically the same as the first embodiment, but with the following substitutions:

[0056] In step S1, a poplar wood veneer is selected as the peeled veneer; in step S3, the viscosity of the isocyanate adhesive is 180-185 mPa·s, the isocyanate content is 30.5-31%, and the density is 1.22-1.25 g / cm3; the pressure of the continuous induction atomization spray rod for gluing is 9-10 Bar, the gluing temperature is 53-55°C, and the amount of glue applied is 35 g / ㎡; in step S5, microwave heating is used to quickly raise the temperature of the inner layer of the core of the slab to 5 0-52℃; the high temperature and pressure rising zone is to increase the hot pressing temperature to 150℃, and the hot pressing pressure is increased to 118N / ㎝2; the high pressure insulation zone is to maintain the hot pressing temperature at 150-152℃, the hot pressing pressure is 70-72N / ㎝2, the hot pressing speed is 60mm / s, and the hot pressing factor is 45.3s / mm; the cooling and thickness setting zone is to reduce the hot pressing temperature from 150-152℃ to 130℃; the cooling and pressure reduction zone is to reduce the temperature to below 100℃ and the pressure to 60N / ㎝2.

[0057] Comparative Example 1

[0058] Comparative Example 1 is basically the same as Example 1, but in step S7, the step of sending the top surface board and the bottom surface board into the veneer device for cladding is replaced by: applying adhesive on the bottom surface board using a glue roller, and then placing the core board on it, applying adhesive on the core board using a glue roller, and then placing the top surface board on the core board, that is, the top surface board and the bottom surface board are clad by manual stacking.

[0059] Comparative Example 2

[0060] Comparative Example 2 is basically the same as Example 2, but in step S7, the step of sending the top surface board and the bottom surface board into the veneer device to veneer is replaced by: applying adhesive on the bottom surface board using a glue roller, and then placing the core board on it, applying adhesive on the core board using a glue roller, and then placing the top surface board on the core board, that is, the top surface board and the bottom surface board are veneered by manual stacking.

[0061] Comparative Example 3

[0062] Comparative Example 3 is basically the same as Example 3, but in step S7, the step of sending the top surface board and the bottom surface board into the veneer device for cladding is replaced by: applying adhesive on the bottom surface board using a glue roller, and then placing the core board on it, applying adhesive on the core board using a glue roller, and then placing the top surface board on the core board, that is, the top surface board and the bottom surface board are clad by manual stacking.

[0063] The plywood of Examples 1 to 3 and Comparative Examples 1 to 3 was subjected to performance testing. Formaldehyde emission was tested in accordance with "GB / T 39600-2021 Formaldehyde Emission Classification of Wood-Based Panels and Their Products," and bonding strength was tested in accordance with "GB / T 17657 Test Methods for Physical and Chemical Properties of Wood-Based Panels and Veneered Wood-Based Panels." In addition, the plywood of Examples 1 to 3 and Comparative Examples 1 to 3 also referred to the surface bonding strength test method. Three 600 mm × 600 mm specimens were cut from each plywood to be tested. The front and bottom bonding strengths of the specimens were tested, and the average surface bonding strength was calculated. The test results are shown in Table 1:

[0064] Table 1 Plywood performance test results

[0065]

[0066] It can be seen from the above test results that the use of a veneer device to laminate the top and bottom panels can significantly improve the bonding strength, and the front and bottom bonding strengths are more uniform, which can better solve the problem of uneven bonding strength.

[0067] The foregoing descriptions of specific exemplary embodiments of the present invention are for the purpose of illustration and description. These descriptions are not intended to limit the invention to the precise form disclosed, and it is obvious that many changes and variations can be made based on the above teachings. Although an embodiment of the present invention has been shown and described, this specific embodiment is only an explanation of the present invention and is not a limitation of the invention. The specific features, structures, materials or characteristics described can be combined in an appropriate manner in any one or more embodiments or examples. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can make modifications, substitutions, variations and various different selections and changes to the embodiments as needed without departing from the principles and purpose of the present invention after reading this specification, but they are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. An automated manufacturing method for formaldehyde-free moisture-proof plywood, characterized in that The following steps are involved: S1. Pretreatment of peeled veneer: Select one or more of eucalyptus, birch, sycamore and poplar as peeled veneer, drying, so that the moisture content of the veneer is controlled within the range of 10-15%; S2. Single-sheet splicing process: Splice the dried single sheets into a single sheet of the designed size and store them for later use; S3. Gluing: A rail-mounted trolley transports the whole veneer sheets to the robotic stacking station. The robot, assembling the sheets in alternating horizontal and vertical directions, picks up the whole veneer sheets one by one and places them on the gluing conveyor line. The gluing conveyor line then delivers the whole veneer sheets to the dual-fluid automatic atomizing gluing area, where isocyanate adhesive and curing agent are sprayed. S4. Intelligent stacking of whole veneer sheets: The automatic assembly head stacks the glued whole veneer sheets in alternating horizontal and vertical stacking to create the desired number of layers. S5. Microwave preheating: The assembled slabs are heated by microwaves on the slab conveyor line, rapidly raising the temperature of the inner core of the slab to 50-60°C. S6. Slab processing: The microwave-preheated slab is continuously hot-pressed, then sawn, cooled, and cured to obtain the core board. S7. The core board is glued and fed into a veneer device to be laminated with the top and bottom sheets. After cold pressing, trimming, hot pressing, and polishing, the formaldehyde-free moisture-proof plywood is obtained. In step S7, the veneer device includes a first conveyor, a second conveyor and a third conveyor with the same conveying direction, the first conveyor, the second conveyor and the third conveyor are arranged at intervals from top to bottom, and further include a first flip conveyor, a second flip conveyor and a limiting device, the loading end of the first flip conveyor is rotatably connected to the unloading end of the first conveyor, the unloading end is provided with a rotatable guide roller, the guide roller can move outward along the unloading end of the first flip conveyor, and a visual camera is provided below the first flip conveyor; the loading end of the second flip conveyor is rotatably connected to the unloading end of the second conveyor; the limiting device is slidably provided on the third conveyor, and a limiting plate is provided on the limiting device, and the direction of the limiting plate is opposite to the conveying direction of the third conveyor; The laminating of the top surface plate and the bottom surface plate includes the following steps: the first conveyor, the second conveyor and the third conveyor respectively convey the top surface plate, the core plate and the bottom surface plate; when the bottom surface plate moves to the bottom of the unloading end of the second flip conveyor, the second flip conveyor flips downward, and the core plate moves downward along the second flip conveyor and is laminated from the front side of the bottom surface plate; at the same time, the limiting device moves to the front of the core plate and the bottom surface plate, and the limiting plate of the limiting device moves downward to block the front side of the core plate and the bottom surface plate, so that the front sides of the core plate and the bottom surface plate remain flush, and move forward with the core plate and the bottom surface plate; the first flip conveyor also flips downward, conveys the top surface plate to the core plate and laminates from the front side of the core plate; the limiting device remains in front of the top surface plate, core plate and bottom surface plate, so that the front sides of the top surface plate, core plate and bottom surface plate remain flush, and the rear limiting plate moves upward, so that the laminated top surface plate, core plate and bottom surface plate move along the third conveyor to the feed and discharge power rolling line, and then are conveyed to the cold press.

2. The automated manufacturing method of formaldehyde-free moisture-proof plywood according to claim 1, characterized in that: In step S3, the viscosity of the isocyanate adhesive is 150-250 mPa·s, the isocyanate content is 30.5-32%, and the density is 1.22-1.25 g / cm 3 .

3. The automated manufacturing method of formaldehyde-free moisture-proof plywood according to claim 1, characterized in that: In step S3, glue is applied in the dual-fluid automatic atomization gluing area using a single-sided gluing method. The isocyanate adhesive is transported to the continuous induction atomization spray rod through a closed channel, and after atomization, glue droplets are formed and applied to the entire surface of the veneer. The pressure of the continuous induction atomization spray rod for gluing is 5-10 Bar, the gluing temperature is 45-60°C, and the amount of glue applied is 25-50g / ㎡.

4. The automated manufacturing method of formaldehyde-free moisture-proof plywood according to claim 1, characterized in that: In step S5, continuous hot pressing specifically includes: the microwave preheated slab is sequentially passed through a high-temperature pressurization zone, a high-temperature holding zone, a cooling and thickness setting zone, and a cooling and pressure reduction zone for continuous hot pressing, wherein the high-temperature pressurization zone is a zone where the hot pressing temperature is raised to T and the hot pressing pressure is raised to F, and the high-temperature holding zone is a zone where the hot pressing temperature T and the hot pressing pressure F are maintained, wherein the hot pressing temperature T is 140-195°C and the hot pressing pressure F is 65-120N / cm 2 The hot pressing speed is 50-300mm / s, the hot pressing factor is 10-50s / mm, the cooling and thickness setting zone is to reduce the hot pressing temperature T to 130-(T-10)℃, the cooling and pressure reduction zone is to reduce the temperature to below 100℃ and the pressure to 60-80N / ㎝ 2 .

5. The automated manufacturing method of formaldehyde-free moisture-proof plywood according to claim 1, characterized in that: The veneer device also includes a fourth conveyor and a lifting conveyor, the unloading end of the fourth conveyor is docked with the loading end of the third conveyor, and the loading end of the fourth conveyor extends to the side of the third conveyor; the unloading end of the fourth conveyor is provided with a plurality of conveying rollers, the rotation axis of the conveying rollers is consistent with the conveying direction of the third conveyor, and the conveying rollers are arranged at equal intervals, and the height of the conveying surface of the fourth conveyor is lower than the height of the conveying surface of the third conveyor; the lifting conveyor includes a base, a lifting frame, a lifting drive assembly and a lifting pulley, and the base is fixed It is fixedly installed below the unloading end of the fourth conveyor, one end of the lifting drive assembly is connected to the base, and the other end of the lifting drive assembly is connected to the lifting frame and can drive the lifting frame to rise and fall in the vertical direction; there are several groups of lifting pulleys, each group of the lifting pulleys is installed on the lifting frame at equal intervals, and the positions of the lifting pulleys are staggered with the positions of the conveying rollers, and a lifting conveyor belt is wrapped around the periphery of each group of the lifting pulleys. The conveying direction of the lifting conveyor belt is consistent with the conveying direction of the third conveyor, and each group of the lifting pulleys can operate synchronously.

6. The automated manufacturing method of formaldehyde-free moisture-proof plywood according to claim 1, characterized in that: The distance from the unloading end of the first overturning conveyor to the discharging end of the third conveyor is smaller than the distance from the unloading end of the second overturning conveyor to the discharging end of the third conveyor.

7. The automated manufacturing method of formaldehyde-free moisture-proof plywood according to claim 1, characterized in that: An introduction block is installed at the unloading end of the second flip conveyor. The bottom of the introduction block is provided with an arc surface, and the top of the introduction block is provided with a detachable nylon plate. The top surface of the nylon plate is not higher than the conveying plane of the second flip conveyor.

8. The automated manufacturing method of formaldehyde-free moisture-proof plywood according to claim 1, characterized in that: The limiting device also includes a movable column and a movable beam, the movable columns having two in total, one end of each of the two movable columns being slidably mounted on the side of the third conveyor, and the two ends of the movable beam being slidably connected to the side of one of the movable columns, the number of the limiting plates being several, and each of the limiting plates being installed on the movable beam at intervals, so that when the movable beam slides along the movable column, the limiting plates can be moved closer to or away from the conveying plane of the third conveyor; The third conveyor is provided with a third conveyor belt, and the number of the third conveyor belts is several, and the third conveyor belts are arranged at equal intervals. When the limit plate approaches the conveying plane of the third conveyor, the bottom of the limit plate can extend into the area between the third conveyor belts.

9. The automated manufacturing method of formaldehyde-free moisture-proof plywood according to claim 1, characterized in that: The veneer device also includes a first hydraulic cylinder and a second hydraulic cylinder; the telescopic end of the first hydraulic cylinder is connected to the front bottom of the first turning conveyor, and the fixed end is fixed; the telescopic end of the second hydraulic cylinder is connected to the front bottom of the second turning conveyor, and the fixed end is fixed.

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