A new process for preparing a bamboo tray

Abstract

This invention provides a novel bamboo pallet manufacturing process, relating to the field of pallet processing technology. The novel bamboo pallet manufacturing process includes preliminary treatment, pre-processing, mid-processing, and final assembly. The preliminary treatment includes bamboo cutting, bamboo impaction, and rough milling. Based on the conical shape of the bamboo, the bamboo is cut to the required length and dimensions according to product requirements and specifications. The bamboo segments are then split into pieces, sorted by thickness and width, and the outer green and yellow parts are removed. Through a combination of drying, carbonization, hot pressing, and cold pressing processes, along with subsequent curing treatments, the internal stress of the bamboo is effectively eliminated, significantly reducing its moisture absorption expansion and drying shrinkage rates. The resulting bamboo panels have good flatness and low warping. The pallets made from this process maintain excellent dimensional stability and structural integrity even under complex temperature and humidity environments, extending their service life.

Description

Technical Field

[0001] This invention relates to the field of pallet processing technology, specifically a novel bamboo pallet manufacturing process. Background Technology

[0002] As an environmentally friendly logistics carrier, bamboo pallets have a technological background that can be traced back to the weaving and processing techniques of traditional bamboo utensils. Bamboo, as a natural and renewable material, has the characteristics of short growth cycle and excellent mechanical properties. It has high axial tensile strength and compressive strength, as well as a certain degree of flexibility and impact resistance. In the pallet manufacturing field, bamboo is mainly prepared into bamboo strips, bamboo sheets or bamboo boards through processes such as cutting, planing, drying and mildew prevention treatment. Then, it is formed into pallet structures through processes such as weaving, nailing or gluing.

[0003] Early bamboo pallets were mostly hand-woven, using interlaced bamboo strips to form a load-bearing surface and reinforced with bamboo frames. With industrial development, bamboo processing gradually incorporated technologies such as mechanical cutting, high-temperature carbonization, and insect-proof and anti-corrosion impregnation, improving the material's durability and environmental adaptability. In terms of structural design, common bamboo pallet forms include single-layer plank type and double-layer bidirectional cross-type locally reinforced design. During the manufacturing process, metal fasteners or special adhesives are often used to connect components.

[0004] The biggest problem with existing processing methods is their lack of control and inconsistency in quality. Bamboo drying often relies on natural air drying or rudimentary earthen kilns, and the moisture content depends entirely on the weather and the feel of the material. This makes the finished pallets extremely prone to cracking in dry areas and mold in humid areas. The load-bearing strength is as unstable as a lottery. Size processing relies on manual labor or simple machinery, resulting in large errors. When assembled, the gaps are obvious and the structure is loose. Therefore, those skilled in the art have provided a new bamboo pallet manufacturing process to solve the problems mentioned in the background art. Summary of the Invention

[0005] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a novel bamboo pallet manufacturing process that solves the problems of inherent deficiencies, instability, and low efficiency in existing technologies.

[0006] (II) Technical Solution To achieve the above objectives, the present invention is implemented through the following technical solution: a novel bamboo pallet manufacturing process, including preliminary treatment, pre-processing, mid-processing and final assembly, characterized in that: the preliminary treatment includes bamboo cutting, bamboo striking and rough milling, according to the conical characteristics of bamboo, the length of bamboo is cut according to product requirements and specifications, and the bamboo nodes are broken into pieces, the thickness and width are sorted, and the green and yellow parts of the bamboo pieces are removed at the same time; The preliminary processing includes carbonization, drying, fine milling, and color selection. High-temperature carbonization is used to remove sugar and oil from bamboo strips, kill bacteria and insect eggs inside the bamboo, and drying equipment is used to reduce the moisture content of bamboo strips to prevent mold and insect infestation. The quality, width, and thickness of bamboo are determined to ensure uniformity of appearance. Bamboo strips with similar colors are selected to avoid color differences in the finished product. The intermediate processing includes arranging bamboo strips, splicing, hot pressing, and cold pressing. Arranging bamboo strips in advance can clarify the placement of bamboo strips and avoid repeated adjustments during splicing. By splicing them crosswise or along the grain, and evenly applying special glue, the stress direction of the bamboo fibers is integrated. Hot pressing equipment is used to squeeze them and promote the rapid curing of the glue. The cooling effect of cold pressing is used to suppress the thermal expansion and contraction of the bamboo board and avoid warping and bending during the cooling process, thus ensuring the flatness and dimensional stability of the board. The final assembly includes sanding, CNC cutting, and automatic pallet assembly. Sanding equipment is used to remove excess glue left after splicing and hot pressing of the main board. A computer numerical control cutting center is used to cut the sanded large-format bamboo boards according to the pallet design drawings. The various bamboo parts cut by CNC are then assembled into a pallet using an automatic pallet assembly machine.

[0007] Preferably, the preliminary treatment of the bamboo includes raw material screening and classification, selecting bamboo aged 3.5 to 5 years, removing bamboo with a middle bend height exceeding 2% of the bamboo length during the selection process, and sawing off bamboo sections with insect holes or mold spots, and cutting a section further back and forth to ensure complete removal of lesions; accurately calculating the length, the final length of the bamboo tube = the length of the bamboo strips designed for the tray + the reserved processing allowance, leaving a length of 20mm to 30mm at each end, and using a tabletop circular saw to cut the bamboo, first cutting off the thickest part at the root with hairs and the excessively thin and thin-walled part at the tip; The bamboo impact process includes incoming material preparation and pretreatment. A radial bamboo splitting machine is used for the bamboo impact process. First, ensure that the length of the bamboo tubes is consistent. Adjust the distance between the cutter discs according to the width of the bamboo strips. During operation, flatten the end face of the bamboo tube, align it with all the cutter discs, and push it forward at a stable and appropriate speed so that the center of the cutter disc is aligned with the center line of the bamboo node to minimize cracking. A four-sided planer is used as the rough milling equipment. In the early stage of processing, the single-sided single-cut depth is adjusted to be controlled within 1.5mm to 3.0mm to avoid vibration, tearing of bamboo fibers or breakage of bamboo strips. The feeding speed is controlled at 10 to 20 meters per minute. During rough milling, all bamboo strips should be processed with the yellow side facing up. Bamboo shavings generated during processing are promptly conveyed and discharged using a conveyor belt.

[0008] Preferably, the drying process involves uniformly and stably reducing the moisture content of the bamboo strips from 30% to 40% or higher after initial milling to a target range of 8% to 12%, while minimizing deformation, cracking, and mold growth. Specific drying steps are as follows: S1. Preparation before drying: Dry bamboo strips of different thicknesses and widths in batches. Place pads with a thickness of 25mm to 30mm at the bottom of the bamboo strip pile, and leave even gaps between the bamboo strips to ensure unobstructed airflow. S2. Drying Process Control: First Stage: Preheating and Moisturizing. Dry bulb temperature controlled at 60℃ to 65℃, high-temperature environment RH>85%, wet bulb temperature 58℃ to 62℃, overall time controlled at 8 to 12 hours. This ensures uniform heating of the bamboo chips, preventing premature surface hardening and allowing internal moisture migration channels. Second Stage: Constant-Range Dehumidification. Dry bulb temperature controlled at 68℃ to 75℃, gradually reducing humidity from 65% to 50%, wet bulb temperature 65℃ to 68℃, overall time controlled at 24 to 36 hours. This stage allows for rapid evaporation of free water from the potato chip surface, a critical period for preventing cracking, requiring stable dehumidification. Third Stage: Slow-Moving Drying. Dry bulb temperature controlled at 78℃ to 85℃, low-humidity environment RH40%-30%, wet bulb temperature 68℃ to 70℃, overall time... The process involves several stages: 1) **Temperature Adjustment:** The dry-bulb temperature is controlled at 70°C to 75°C, and the bamboo strips are rehydrated to 45%-55% RH to eliminate internal stress, balance internal and external moisture content, and prevent immediate cracking after firing. This stage lasts 6 to 12 hours. 2) **Cooling:** The bamboo strips are allowed to cool naturally to <40°C, the heat source is turned off, and the fan is used for circulation to stabilize the bamboo strips and prepare them for firing. This stage lasts 4 to 8 hours. After firing, the bamboo strips are stacked and stored in a constant temperature and humidity workshop for at least 24 to 48 hours. The temperature in the constant temperature and humidity workshop is 20°C to 25°C, and the humidity is 50% to 60%. This allows residual stress to be released and the moisture content to reach a uniform balance within the entire batch of bamboo and in the air. The carbonization process involves high-temperature treatment to permanently alter the chemical composition and physical structure of bamboo, achieving the goals of mold and insect resistance, dimensional stability, and color modification. The manufacturing steps are as follows: S1. Pre-treatment: After drying, the bamboo strips are neatly and evenly stacked on the kiln car or support, with spacers between layers to ensure that high-temperature steam and hot air can pass through each bamboo strip evenly and smoothly. S2. Kiln loading and sealing: Push the kiln car loaded with bamboo strips into the carbonization kiln, close the kiln door, and ensure that the kiln body is highly sealed. S3. Heating and humidifying: Inject saturated steam or spray atomized water into the kiln. In the initial stage of heating, rapidly increase the relative humidity in the kiln to over 90%. At the same time, raise the temperature from room temperature to around 100°C at a slower rate and keep it warm for a period of time. Use the high temperature and high humidity environment to fully soften and plasticize the bamboo fibers, reduce the stress caused by subsequent high temperature, and prevent pressure buildup from causing cracking. S4. High-temperature carbonization: Stop or significantly reduce the steam supply, and switch the medium in the kiln to high-temperature hot air. Raise the temperature to the target carbonization temperature at a rate of 5°C to 10°C / hour. Control the carbonization temperature at 180°C to 200°C and keep it at that temperature for 2 to 4 hours. S5. Cooling and Humidification: Turn off the heat source and allow the temperature inside the kiln to drop slowly and naturally, or cool it down at a rate of 10°C to 15°C / hour through the cooling system. When the temperature drops to 50°C to 60°C, a small amount of steam or atomized water can be injected into the kiln for humidification treatment, so that the extremely dry bamboo strips can absorb a small amount of moisture, release internal stress, and prevent cracking immediately after leaving the kiln. S6. Kiln exit and curing: Open the kiln door, push out the kiln car, and place the carbonized bamboo strips in a constant temperature and humidity workshop for 24 to 48 hours for curing. This allows the moisture content to fully balance with the workshop environment and the performance to be completely stable before proceeding to the next process. The precision milling and color selection are typically performed on a high-precision four-sided planer. Specific machining parameters are as follows: Target dimensional accuracy: thickness and width tolerance ±0.1mm to ±0.2mm; Surface finish: Ra≤6.3μm; Machining allowance: single-sided cutting amount is typically 0.5mm to 1.5mm; Feed rate: 15m to 25m / min; Tool requirements: diamond tools or ultra-fine ground carbide tools; Spindle speed: 4000 to 6000rpm. The color selection process in the fine milling and color selection is a processing step in bamboo processing that enhances product added value and appearance consistency. By using a high-resolution camera and AI recognition system, the bamboo pieces are automatically sorted according to a set color difference threshold and then placed separately.

[0009] Preferably, the arrangement of bamboo strips is to arrange bamboo strips into a board blank that meets the requirements in terms of size, structure, density and appearance. Arranging the bamboo strips in advance can clarify the placement of the bamboo strips, avoid repeated adjustments during splicing, reduce material waste, ensure a smooth production process, determine the number of bamboo strips according to product specifications, and separate the front panel, back panel and middle panel, which facilitates the splicing production of the next process and avoids quality problems caused by insufficient or incorrect bamboo strips. During the processing of the bamboo strips, after arranging the sorted bamboo strips, a roller brush is used to coat the surface of the bamboo strips with glue. The glue is made of phenolic resin. The scattered bamboo strips are spliced ​​into large bamboo boards. By splicing them in a cross or along the grain, the stress direction of the bamboo fibers is integrated. During splicing, the texture and color are unified, which enhances the bending and compressive strength of the board and makes the finished product more durable and less prone to deformation. At the same time, small pieces and corner bamboo strips are fully utilized to reduce raw material waste and lower production costs. Packing straps are used to bind and position them.

[0010] Preferably, the hot pressing is a process in which the slabs prepared in the sheet-laying process are cured into a solid, integral sheet using an adhesive under precisely controlled temperature, pressure, and time. Specifically, it includes the following steps: S1. Pre-press preparation: Ensure the adhesive is slightly sticky but not dry, and use an infrared thermometer or surface thermocouple to measure the hot press at multiple points. Control the temperature difference on the hot plate surface within ±3℃. At the same time, thoroughly clean the heating plate surface to prevent the old adhesive from carbonizing and affecting heat transfer and plate quality. S2. Centering control: Each layer of board must be centered and separated by pressure-resistant technical spacers of equal thickness and height to ensure absolutely uniform stress on each layer. Segmented pressing is used to achieve full thickness pressing. Due to glue flow and bamboo compression, the pressure will decrease slightly. Specific parameters are: hot pressing temperature: 130℃ to 150℃; unit pressure: 2.5MPa to 4.0MPa; hot pressing time: 0.8 minutes to 1.5 minutes / mm board thickness; board closing speed: fast closing in the early stage and slow pressing in the later stage; pressure holding and cooling: cooling under pressure until the core temperature of the board is <60℃.

[0011] Preferably, the cold pressing utilizes the cooling effect of cold pressing to suppress the thermal expansion and contraction of bamboo boards, preventing warping and bending during the cooling process, ensuring the flatness and dimensional stability of the boards, further compacting the splicing interface, allowing the incompletely cured adhesive to fully penetrate under pressure, improving bonding strength, preventing delamination later, and smoothing out any minor protrusions that may appear after hot pressing, making the board surface smoother, reducing the workload of subsequent processes, and rapid cooling can accelerate the complete curing of the adhesive, reducing waiting time and improving overall production efficiency.

[0012] Preferably, the sanding is to eliminate unevenness, glue marks, slight indentations and processing defects on the surface of the board, and obtain a smooth, flat and uniform surface. The board blank is sanded using a sander, which is equipped with sanding belts of 80 grit, 150 grit to 240 grit. During the sanding process, the tiny protrusions and burrs on the surface of the bamboo board can be removed simultaneously, further improving the flatness of the board.

[0013] Preferably, the CNC cutting piece is cut using a computer numerical control (CNC) cutting center. The cutting is controlled by a program, resulting in minimal error and ensuring that each bamboo board is the same size, meeting the product assembly accuracy requirements. This avoids the dimensional deviations of manual cutting. The CNC system can automatically optimize the layout, maximize the use of bamboo board raw materials, reduce waste of scraps, lower production costs, and improve resource utilization. Different sizes and shapes can be cut according to customer needs.

[0014] Preferably, the automatic pallet assembly includes the following steps: S1. Check the air source and power supply, start the assembly line, and calibrate the sensors and robotic arms at each workstation; S2. Material supply and positioning: The longitudinal beams, foot piers, and panels are accurately delivered to their respective workstations through the material supply system; S3. Automatic nailing prevents the bottom panel from being nailed. A multi-head nail gun drives in bamboo and wood special screws according to the set program to connect the panel, foot block and longitudinal beam. The station is flipped to prevent the top panel from being nailed and top-mounted. S4. Process monitoring: The system automatically detects material shortages and misalignments, and operators can monitor and listen for abnormal sounds. S5. Finished Product Output and Final Inspection: Finished product pallets are output, and random checks are performed on appearance, dimensions, diagonals, and structure. The system automatically completes the positioning, splicing, and fastening processes of bamboo boards cut from data. The batch assembly speed far exceeds that of manual assembly, significantly shortening the production cycle and adapting to the needs of large-scale production. At the same time, the positioning and splicing pressure are controlled by the program to ensure that the structural dimensions and slat spacing of the bamboo pallets are consistent, avoiding deviations in manual assembly and improving the product assembly accuracy and stability.

[0015] (III) Beneficial Effects This invention provides a novel process for manufacturing bamboo trays. It offers the following advantages: 1. In this invention, the combined process of drying, carbonization, hot pressing and cold pressing, and subsequent curing treatment effectively eliminates the internal stress of bamboo, significantly reduces its moisture absorption expansion and drying shrinkage rate, and the resulting bamboo board has good flatness and low warping. The pallets made from it can still maintain excellent dimensional stability and structural integrity under complex temperature and humidity environments, thus extending their service life.

[0016] 2. In this invention, a cross- or parallel-grain splicing process is adopted to scientifically integrate the stress direction of bamboo fiber. Combined with a precisely controlled hot pressing process, the bonding interface has high strength, and the final product's bending resistance, compression resistance and impact resistance are significantly improved, fully meeting the heavy load and stacking requirements of logistics warehousing, and its durability far exceeds that of ordinary wooden pallets.

[0017] 3. In this invention, the high-temperature carbonization process permanently removes nutrients such as sugar and starch from the bamboo, and kills bacteria and insect eggs. Combined with a drying process that precisely controls the moisture content, the risk of mold, insect infestation or decay during storage, transportation and use is fundamentally eliminated. It is particularly suitable for environments with high requirements for hygiene and durability.

[0018] 4. In this invention, precision milling ensures the dimensional accuracy of bamboo strips, and an innovative AI recognition system is introduced for automatic color selection, realizing intelligent sorting and matching of bamboo strip colors. The final product has a smooth and flat surface, minimal color difference, and harmonious texture, possessing high appearance consistency and commercial quality, thereby enhancing product added value and market competitiveness. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall processing technology in this invention. Detailed Implementation

[0020] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1: like Figure 1 As shown, this embodiment of the invention provides a novel bamboo pallet manufacturing process, including preliminary treatment, pre-processing, mid-processing and final assembly. The preliminary treatment includes bamboo cutting, bamboo striking and rough milling. According to the conical characteristics of bamboo, the length of bamboo is cut according to product requirements and specifications, and bamboo nodes are broken into pieces, and the thickness and width are sorted. At the same time, the green and yellow parts of the bamboo pieces are removed. The initial processing includes carbonization, drying, fine milling, and color selection. High-temperature carbonization is used to remove sugar and oil from bamboo strips, kill bacteria and insect eggs inside the bamboo, and drying equipment is used to reduce the moisture content of bamboo strips to prevent mold and insect infestation. The quality, width, and thickness of bamboo are determined to ensure uniformity of appearance. Bamboo strips with similar colors are selected to avoid color differences in the finished product. Mid-term processing includes arranging bamboo strips, splicing, hot pressing, and cold pressing. Arranging bamboo strips in advance can clarify the placement of bamboo strips and avoid repeated adjustments during splicing. By splicing them crosswise or along the grain, and evenly applying special glue, the stress direction of the bamboo fibers is integrated. Hot pressing equipment is used to compress the bamboo strips and promote the rapid curing of the glue. The cooling effect of cold pressing is used to suppress the thermal expansion and contraction of the bamboo board and avoid warping and bending during the cooling process, ensuring the flatness and dimensional stability of the board. The final assembly includes sanding, CNC cutting, and automatic pallet assembly. Sanding equipment is used to remove excess glue left after splicing and hot pressing of the main board. A computer numerical control cutting center is used to cut the sanded large-format bamboo boards according to the pallet design drawings. The various bamboo parts cut by CNC are then assembled into pallets using an automatic pallet assembly machine.

[0022] The initial treatment of interrupted bamboo includes raw material screening and classification. Bamboo aged 3.5 to 5 years is selected. During the selection process, bamboo with a middle bend height exceeding 2% of the bamboo length is removed. For bamboo nodes with insect holes or mold spots, the entire section needs to be sawed off, and a section is cut forward and backward to ensure that the disease is completely removed. The length is accurately calculated. The final length of the bamboo tube = the length of the bamboo strip designed for the tray + the reserved processing allowance. A length of 20mm to 30mm is reserved at each end. The bamboo is cut with a tabletop circular saw. First, the thickest part with hairs at the root and the excessively thin and thin-walled part at the tip are cut off. Bamboo impacting includes incoming material preparation and pretreatment. A radial bamboo splitting machine is used for bamboo impacting. First, ensure that the length of the bamboo tubes is consistent. Adjust the distance between the cutter discs according to the width of the bamboo strips. During operation, flatten the end face of the bamboo tube, align it with all the cutter discs, and push it forward at a stable and appropriate speed so that the center of the cutter disc is aligned with the center line of the bamboo node to minimize cracking. A four-sided planer is used as the rough milling equipment. In the early stage of processing, the single-sided single-cut depth is adjusted to be controlled within 1.5mm to 3.0mm to avoid vibration, tearing of bamboo fibers or breakage of bamboo strips. The feeding speed is controlled at 10 to 20 meters per minute. During rough milling, all bamboo strips should be processed with the yellow side facing up. Bamboo shavings generated during processing are promptly conveyed and discharged using a conveyor belt.

[0023] Drying involves uniformly and stably reducing the moisture content of bamboo strips from 30% to 40% or higher after initial milling to the target range of 8% to 12%, while minimizing deformation, cracking, and mold growth. The specific drying steps are as follows: S1. Preparation before drying: Dry bamboo strips of different thicknesses and widths in batches. Place pads with a thickness of 25mm to 30mm at the bottom of the bamboo strip pile, and leave even gaps between the bamboo strips to ensure unobstructed airflow. S2. Drying Process Control: First Stage: Preheating and Moisturizing. Dry bulb temperature controlled at 60℃ to 65℃, high-temperature environment RH > 85%, wet bulb temperature 58℃ to 62℃, overall time controlled at 8 to 12 hours. This ensures uniform heating of the bamboo chips, preventing premature surface hardening and allowing internal moisture migration channels. Second Stage: Constant-Range Dehumidification. Dry bulb temperature controlled at 68℃ to 75℃, gradually reducing humidity from 65% to 50%, wet bulb temperature 65℃ to 68℃, overall time controlled at 24 to 36 hours. This stage allows for rapid evaporation of free water from the potato chip surface, a critical period for preventing cracking, requiring stable dehumidification. Third Stage: Slow-Moving Drying. Dry bulb temperature controlled at 78℃ to 85℃, low-humidity environment RH 40%-30%, wet bulb temperature 68℃ to 70℃, overall time controlled at 8 to 12 hours. The first stage involves controlling the drying time to 24 to 36 hours to remove bound water from the bamboo cell walls and achieve the target moisture content. The second stage involves conditioning and balancing, with the dry-bulb temperature controlled at 70°C to 75°C and the RH treatment at 45% to 55% to eliminate internal stress, balance the internal and external moisture content, and prevent immediate cracking after firing. The entire process takes 6 to 12 hours. The third stage involves cooling, with the temperature naturally dropping to <40°C, the heat source turned off, and the fan circulated to stabilize the bamboo strips and prepare them for firing. The entire process takes 4 to 8 hours. After firing, the bamboo strips are stacked and stored in a constant temperature and humidity workshop for at least 24 to 48 hours. The temperature in the constant temperature and humidity workshop is 20°C to 25°C, and the humidity is 50% to 60%. The purpose is to release residual stress and achieve a uniform balance of moisture content within the entire batch of bamboo and between the bamboo and the air. Carbonization is a process that uses high temperatures to permanently alter the chemical composition and physical structure of bamboo, achieving effects such as mold and insect resistance, dimensional stability, and color modification. The production steps are as follows: S1. Pre-treatment: After drying, the bamboo strips are neatly and evenly stacked on the kiln car or support, with spacers between layers to ensure that high-temperature steam and hot air can pass through each bamboo strip evenly and smoothly. S2. Kiln loading and sealing: Push the kiln car loaded with bamboo strips into the carbonization kiln, close the kiln door, and ensure that the kiln body is highly sealed. S3. Heating and humidifying: Inject saturated steam or spray atomized water into the kiln. In the initial stage of heating, rapidly increase the relative humidity in the kiln to over 90%. At the same time, raise the temperature from room temperature to around 100°C at a slower rate and keep it warm for a period of time. Use the high temperature and high humidity environment to fully soften and plasticize the bamboo fibers, reduce the stress caused by subsequent high temperature, and prevent pressure buildup from causing cracking. S4. High-temperature carbonization: Stop or significantly reduce the steam supply, and switch the medium in the kiln to high-temperature hot air. Raise the temperature to the target carbonization temperature at a rate of 5°C to 10°C / hour. Control the carbonization temperature at 180°C to 200°C and keep it at that temperature for 2 to 4 hours. S5. Cooling and Humidification: Turn off the heat source and allow the temperature inside the kiln to drop slowly and naturally, or cool it down at a rate of 10°C to 15°C / hour through the cooling system. When the temperature drops to 50°C to 60°C, a small amount of steam or atomized water can be injected into the kiln for humidification treatment, so that the extremely dry bamboo strips can absorb a small amount of moisture, release internal stress, and prevent cracking immediately after leaving the kiln. S6. Kiln exit and curing: Open the kiln door, push out the kiln car, and place the carbonized bamboo strips in a constant temperature and humidity workshop for 24 to 48 hours for curing. This allows the moisture content to fully balance with the workshop environment and the performance to be completely stable before proceeding to the next process. Precision milling and color selection are typically performed on a high-precision four-sided planer. Specific machining parameters are as follows: Target dimensional accuracy: thickness and width tolerance ±0.1mm to ±0.2mm; Surface finish: Ra≤6.3μm; Machining allowance: single-sided cutting amount is typically 0.5mm to 1.5mm; Feed rate: 15m to 25m / min; Tool requirements: diamond tools or ultra-fine ground carbide tools; Spindle speed: 4000 to 6000rpm. Color selection in precision milling and color sorting is a processing step in bamboo processing that enhances product added value and appearance consistency. By using a high-resolution camera and AI recognition system, the bamboo pieces are automatically sorted according to the set color difference threshold and then placed separately.

[0024] Arranging bamboo strips into boards that meet the requirements in terms of size, structure, density, and appearance. Arranging bamboo strips in advance can clarify the placement of bamboo strips, avoid repeated adjustments during splicing, reduce material waste, and ensure a smooth production process. The number of bamboo strips is determined according to the product specifications, and the front panel, back panel, and middle strip are separated to facilitate the splicing production of the next process and avoid quality problems caused by insufficient or incorrect strips. During the processing of the bamboo strips, after arranging the sorted bamboo strips, a roller brush is used to coat the surface of the bamboo strips with glue. The glue is made of phenolic resin. The scattered bamboo strips are spliced ​​into large bamboo boards. By splicing them in a cross or along the grain, the stress direction of the bamboo fibers is integrated. During splicing, the texture and color are unified, which enhances the bending and compressive strength of the board and makes the finished product more durable and less prone to deformation. At the same time, small pieces and corner bamboo strips are fully utilized to reduce raw material waste and lower production costs. Packing straps are used to bind and position them.

[0025] Hot pressing is a process in which the slabs prepared in the sheet-laying process are cured into a solid, integral sheet using adhesives under precisely controlled temperature, pressure, and time. Specifically, it includes the following steps: S1. Pre-press preparation: Ensure the adhesive is slightly sticky but not dry, and use an infrared thermometer or surface thermocouple to measure the hot press at multiple points. Control the temperature difference on the hot plate surface within ±3℃. At the same time, thoroughly clean the heating plate surface to prevent the old adhesive from carbonizing and affecting heat transfer and plate quality. S2. Centering control: Each layer of board must be centered and separated by pressure-resistant technical spacers of equal thickness and height to ensure absolutely uniform stress on each layer. Segmented pressing is used to achieve full thickness pressing. Due to glue flow and bamboo compression, the pressure will decrease slightly. Specific parameters are: hot pressing temperature: 130℃ to 150℃; unit pressure: 2.5MPa to 4.0MPa; hot pressing time: 0.8 minutes to 1.5 minutes / mm board thickness; board closing speed: fast closing in the early stage and slow pressing in the later stage; pressure holding and cooling: cooling under pressure until the core temperature of the board is <60℃.

[0026] Cold pressing utilizes the cooling effect of cold pressing to suppress the thermal expansion and contraction of bamboo boards, preventing warping and bending during the cooling process, ensuring the flatness and dimensional stability of the boards, further compacting the splicing interface, allowing the not fully cured glue to fully penetrate under pressure, improving the bonding strength, and preventing delamination later. Cold pressing can also smooth out any small bumps that may appear after hot pressing, making the board surface smoother, reducing the workload of subsequent processes. Rapid cooling can accelerate the complete curing of the glue, reduce waiting time, and improve overall production efficiency.

[0027] Sanding is used to eliminate unevenness, glue marks, minor indentations, and processing defects on the surface of the board, so as to obtain a smooth, flat, and uniform surface. A sander is used to sand the board blank. The sander is equipped with sanding belts with grits ranging from 80 grit, 150 grit to 240 grit. During the sanding process, tiny protrusions and burrs on the surface of the bamboo board can be removed simultaneously, further improving the flatness of the board.

[0028] The CNC cutting process utilizes a computer numerical control (CNC) cutting center. The cutting is controlled by a program, resulting in minimal error and ensuring that each bamboo board is the same size, meeting the product assembly precision requirements. This avoids the dimensional deviations of manual cutting. The CNC system can automatically optimize the layout, maximizing the use of bamboo raw materials, reducing waste of scraps, lowering production costs, and improving resource utilization. Different sizes and shapes can be cut according to customer needs.

[0029] Automated pallet assembly includes the following steps: S1. Check the air source and power supply, start the assembly line, and calibrate the sensors and robotic arms at each workstation; S2. Material supply and positioning: The longitudinal beams, foot piers, and panels are accurately delivered to their respective workstations through the material supply system; S3. Automatic nailing prevents the bottom panel from being nailed. A multi-head nail gun drives in bamboo and wood special screws according to the set program to connect the panel, foot block and longitudinal beam. The station is flipped to prevent the top panel from being nailed and top-mounted. S4. Process monitoring: The system automatically detects material shortages and misalignments, and operators can monitor and listen for abnormal sounds. S5. Finished Product Output and Final Inspection: Finished product pallets are output, and random checks are performed on appearance, dimensions, diagonals, and structure. The system automatically completes the positioning, splicing, and fastening processes of bamboo boards cut from data. The batch assembly speed far exceeds that of manual assembly, significantly shortening the production cycle and adapting to the needs of large-scale production. At the same time, the positioning and splicing pressure are controlled by the program to ensure that the structural dimensions and slat spacing of the bamboo pallets are consistent, avoiding deviations in manual assembly and improving the product assembly accuracy and stability.

[0030] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A novel bamboo pallet manufacturing process, comprising preliminary treatment, pre-processing, intermediate processing, and final assembly, characterized in that: The preliminary processing includes bamboo cutting, bamboo striking, and rough milling. Based on the conical shape of the bamboo, the bamboo is cut to the required length according to product requirements and specifications. The bamboo segments are then split into pieces, and the thickness and width are sorted. At the same time, the green and yellow parts of the bamboo pieces are removed. The preliminary processing includes carbonization, drying, fine milling, and color selection. High-temperature carbonization is used to remove sugar and oil from bamboo strips, kill bacteria and insect eggs inside the bamboo, and drying equipment is used to reduce the moisture content of bamboo strips to prevent mold and insect infestation. The quality, width, and thickness of bamboo are determined to ensure uniformity of appearance. Bamboo strips with similar colors are selected to avoid color differences in the finished product. The intermediate processing includes arranging bamboo strips, splicing, hot pressing, and cold pressing. Arranging bamboo strips in advance can clarify the placement of bamboo strips and avoid repeated adjustments during splicing. By splicing them crosswise or along the grain, and evenly applying special glue, the stress direction of the bamboo fibers is integrated. Hot pressing equipment is used to squeeze them and promote the rapid curing of the glue. The cooling effect of cold pressing is used to suppress the thermal expansion and contraction of the bamboo board and avoid warping and bending during the cooling process, thus ensuring the flatness and dimensional stability of the board. The final assembly includes sanding, CNC cutting, and automatic pallet assembly. Sanding equipment is used to remove excess glue left after splicing and hot pressing of the main board. A computer numerical control cutting center is used to cut the sanded large-format bamboo boards according to the pallet design drawings. The various bamboo parts cut by CNC are then assembled into a pallet using an automatic pallet assembly machine.

2. The novel bamboo tray manufacturing process according to claim 1, characterized in that: The preliminary treatment of the bamboo includes raw material screening and classification. Bamboo aged 3.5 to 5 years is selected. During the selection process, bamboo with a middle bend height exceeding 2% of the bamboo length is removed. For bamboo nodes with insect holes or mold spots, the entire section needs to be sawed off, and a section is cut off at the front and back to ensure that the disease is completely removed. The length is accurately calculated. The final length of the bamboo tube = the length of the bamboo strip designed for the tray + the reserved processing allowance. A length of 20mm to 30mm is reserved at each end. The bamboo is cut using a tabletop circular saw. First, the thickest part with hairs at the root and the excessively thin and thin-walled part at the tip are cut off. The bamboo impact process includes incoming material preparation and pretreatment. A radial bamboo splitting machine is used for the bamboo impact process. First, ensure that the length of the bamboo tubes is consistent. Adjust the distance between the cutter discs according to the width of the bamboo strips. During operation, flatten the end face of the bamboo tube, align it with all the cutter discs, and push it forward at a stable and appropriate speed so that the center of the cutter disc is aligned with the center line of the bamboo node to minimize cracking. A four-sided planer is used as the rough milling equipment. In the early stage of processing, the single-sided single-cut depth is adjusted to be controlled within 1.5mm to 3.0mm to avoid vibration, tearing of bamboo fibers or breakage of bamboo strips. The feeding speed is controlled at 10 to 20 meters per minute. During rough milling, all bamboo strips should be processed with the yellow side facing up. Bamboo shavings generated during processing are promptly conveyed and discharged using a conveyor belt.

3. The novel bamboo tray manufacturing process according to claim 1, characterized in that: The drying process involves uniformly and stably reducing the moisture content of the bamboo strips from 30% to 40% or higher after initial milling to a target range of 8% to 12%, while minimizing deformation, cracking, and mold growth. The specific drying steps are as follows: S1. Preparation before drying: Dry bamboo strips of different thicknesses and widths in batches. Place pads with a thickness of 25mm to 30mm at the bottom of the bamboo strip pile, and leave even gaps between the bamboo strips to ensure unobstructed airflow. S2. Drying Process Control: First Stage: Preheating and Moisturizing. Dry bulb temperature controlled at 60℃ to 65℃ in a high-temperature environment (RH > 85%), wet bulb temperature at 58℃ to 62℃, total time controlled at 8 to 12 hours. This ensures even heating of the bamboo chips, preventing premature surface hardening and allowing internal moisture to migrate. Second Stage: Constant-Range Dehumidification. Dry bulb temperature controlled at 68℃ to 75℃, gradually reducing humidity (RH 65% → 50%), wet bulb temperature at 65℃ to 68℃, total time controlled at 24 to 36 hours. This stage allows for rapid evaporation of free water from the potato chip surface, a critical period for preventing cracking, requiring stable dehumidification. Third Stage: Slow-Decelerating Drying. Dry bulb temperature controlled at 78℃ to 85℃ in a low-humidity environment (RH 40% - 30%), wet bulb temperature at 68℃ to 70℃, total time controlled at 8 to 12 hours. The first stage involves 24 to 36 hours of conditioning to remove bound water from the bamboo cell walls and achieve the target moisture content. The second stage involves conditioning and balancing, with the dry-bulb temperature controlled at 70°C to 75°C, followed by rehumidification (RH 45%-55%) to eliminate internal stress, balance the internal and external moisture content, and prevent immediate cracking after firing. The entire process takes 6 to 12 hours. The third stage involves cooling, with the temperature naturally dropping to <40°C, the heat source turned off, and the fan circulated to stabilize the bamboo strips and prepare them for firing. This process takes 4 to 8 hours. After firing, the bamboo strips are stacked and stored in a constant temperature and humidity workshop for at least 24 to 48 hours. The temperature in the constant temperature and humidity workshop is 20°C to 25°C, and the humidity is 50% to 60%. The purpose of this is to release residual stress and achieve a uniform moisture content balance within the entire batch of bamboo and between it and the air. The carbonization process involves high-temperature treatment to permanently alter the chemical composition and physical structure of bamboo, achieving the goals of mold and insect resistance, dimensional stability, and color modification. The manufacturing steps are as follows: S1. Pre-treatment: After drying, the bamboo strips are neatly and evenly stacked on the kiln car or support, with spacers between layers to ensure that high-temperature steam and hot air can pass through each bamboo strip evenly and smoothly. S2. Kiln loading and sealing: Push the kiln car loaded with bamboo strips into the carbonization kiln, close the kiln door, and ensure that the kiln body is highly sealed. S3. Heating and humidifying: Inject saturated steam or spray atomized water into the kiln. In the initial stage of heating, rapidly increase the relative humidity in the kiln to over 90%. At the same time, raise the temperature from room temperature to around 100°C at a slower rate and keep it warm for a period of time. Use the high temperature and high humidity environment to fully soften and plasticize the bamboo fibers, reduce the stress caused by subsequent high temperature, and prevent pressure buildup from causing cracking. S4. High-temperature carbonization: Stop or significantly reduce the steam supply, and switch the medium in the kiln to high-temperature hot air. Raise the temperature to the target carbonization temperature at a rate of 5°C to 10°C / hour. Control the carbonization temperature at 180°C to 200°C and keep it at that temperature for 2 to 4 hours. S5. Cooling and Humidification: Turn off the heat source and allow the temperature inside the kiln to drop slowly and naturally, or cool it down at a rate of 10°C to 15°C / hour through the cooling system. When the temperature drops to 50°C to 60°C, a small amount of steam or atomized water can be injected into the kiln for humidification treatment, so that the extremely dry bamboo strips can absorb a small amount of moisture, release internal stress, and prevent cracking immediately after leaving the kiln. S6. Kiln exit and curing: Open the kiln door, push out the kiln car, and place the carbonized bamboo strips in a constant temperature and humidity workshop for 24 to 48 hours for curing. This allows the moisture content to fully balance with the workshop environment and the performance to be completely stable before proceeding to the next process. The precision milling and color selection are typically performed on a high-precision four-sided planer. Specific machining parameters are as follows: Target dimensional accuracy: thickness and width tolerance ±0.1mm to ±0.2mm; Surface finish: Ra≤6.3μm; Machining allowance: single-sided cutting amount is typically 0.5mm to 1.5mm; Feed rate: 15m to 25m / min; Tool requirements: diamond tools or ultra-fine ground carbide tools; Spindle speed: 4000 to 6000rpm. The color selection process in the fine milling and color selection is a processing step in bamboo processing that enhances product added value and appearance consistency. By using a high-resolution camera and AI recognition system, the bamboo pieces are automatically sorted according to a set color difference threshold and then placed separately.

4. The novel bamboo tray manufacturing process according to claim 1, characterized in that: The arrangement of bamboo strips is to arrange bamboo strips into boards that meet the requirements in terms of size, structure, density and appearance. Arranging the bamboo strips in advance can clarify the placement of the bamboo strips, avoid repeated adjustments during splicing, reduce material waste, and ensure a smooth production process. The number of bamboo strips is determined according to the product specifications, and the front panel, back panel and middle strip are separated to facilitate the splicing production of the next process and avoid quality problems caused by missing or incorrect strips. During the processing of the bamboo strips, after arranging the sorted bamboo strips, a roller brush is used to coat the surface of the bamboo strips with glue. The glue is made of phenolic resin. The scattered bamboo strips are spliced ​​into large bamboo boards. By splicing them in a cross or along the grain, the stress direction of the bamboo fibers is integrated. During splicing, the texture and color are unified, which enhances the bending and compressive strength of the board and makes the finished product more durable and less prone to deformation. At the same time, small pieces and corner bamboo strips are fully utilized to reduce raw material waste and lower production costs. Packing straps are used to bind and position them.

5. The novel bamboo tray manufacturing process according to claim 1, characterized in that: The hot pressing process involves curing the slabs prepared in the sheet-laying process into a solid, integral sheet using adhesives under precisely controlled temperature, pressure, and time. Specifically, it includes the following steps: S1. Pre-press preparation: Ensure the adhesive is slightly sticky but not dry, and use an infrared thermometer or surface thermocouple to measure the hot press at multiple points. Control the temperature difference on the hot plate surface within ±3℃. At the same time, thoroughly clean the heating plate surface to prevent the old adhesive from carbonizing and affecting heat transfer and plate quality. S2. Centering control: Each layer of board must be centered and separated by pressure-resistant technical spacers of equal thickness and height to ensure absolutely uniform stress on each layer. Segmented pressing is used to achieve full thickness pressing. Due to glue flow and bamboo compression, the pressure will decrease slightly. Specific parameters are: hot pressing temperature: 130℃ to 150℃; unit pressure: 2.5MPa to 4.0MPa; hot pressing time: 0.8 minutes to 1.5 minutes / mm board thickness; board closing speed: fast closing in the early stage and slow pressing in the later stage; pressure holding and cooling: cooling under pressure until the core temperature of the board is <60℃.

6. The novel bamboo tray manufacturing process according to claim 1, characterized in that: The cold pressing process utilizes the cooling effect of cold pressing to suppress the thermal expansion and contraction of bamboo boards, preventing warping and bending during the cooling process, ensuring the flatness and dimensional stability of the boards, further compacting the splicing interface, allowing the incompletely cured adhesive to fully penetrate under pressure, improving bonding strength, and preventing delamination later. Cold pressing can also smooth out any minor protrusions that may appear after hot pressing, making the board surface smoother, reducing the workload of subsequent processes, and rapid cooling can accelerate the complete curing of the adhesive, reducing waiting time and improving overall production efficiency.

7. The novel bamboo tray manufacturing process according to claim 1, characterized in that: The sanding process aims to eliminate unevenness, glue marks, minor indentations, and processing defects on the surface of the board, thereby obtaining a smooth, flat, and uniform surface. The board blank is sanded using a sander, which is equipped with sanding belts ranging from 80 grit, 150 grit to 240 grit. During the sanding process, tiny protrusions and burrs on the surface of the bamboo board can be removed simultaneously, further improving the flatness of the board.

8. The novel bamboo tray manufacturing process according to claim 1, characterized in that: The CNC cutting sheet is produced using a computer numerical control cutting center. The cutting is controlled by a program, resulting in minimal error and ensuring that each bamboo board is the same size, meeting the product assembly accuracy requirements. This avoids the dimensional deviations of manual cutting. The CNC system can automatically optimize the layout, maximize the use of bamboo board materials, reduce waste of scraps, lower production costs, and improve resource utilization. Different sizes and shapes can be cut according to customer needs.

9. The novel bamboo tray manufacturing process according to claim 1, characterized in that: The automated pallet assembly includes the following steps: S1. Check the air source and power supply, start the assembly line, and calibrate the sensors and robotic arms at each workstation; S2. Material supply and positioning: The longitudinal beams, foot piers, and panels are accurately delivered to their respective workstations through the material supply system; S3. Automatic nailing prevents the bottom panel from being nailed. A multi-head nail gun drives in bamboo and wood special screws according to the set program to connect the panel, foot block and longitudinal beam. The station is flipped to prevent the top panel from being nailed and top-mounted. S4. Process monitoring: The system automatically detects material shortages and misalignments, and operators can monitor and listen for abnormal sounds. S5. Finished Product Output and Final Inspection: Finished product pallets are output, and random checks are performed on appearance, dimensions, diagonals, and structure. The system automatically completes the positioning, splicing, and fastening processes of bamboo boards cut from data. The batch assembly speed far exceeds that of manual assembly, significantly shortening the production cycle and adapting to the needs of large-scale production. At the same time, the positioning and splicing pressure are controlled by the program to ensure that the structural dimensions and slat spacing of the bamboo pallets are consistent, avoiding deviations in manual assembly and improving the product assembly accuracy and stability.

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