Online automatic measurement method for moisture content of sawn timber and production line

Abstract

The present application provides a kind of saw material moisture content online automatic measurement method and production line, the production line can be measured saw material with automatic transmission root / each piece, high-definition camera for shooting the surface condition of measured saw material is installed at the entrance end of production line, mechanical hand for fixing moisture content detection probe is installed on production line;Production line control unit shoots the surface image of each saw material by high-definition camera, the type of measured saw material is quickly identified according to image, control unit controls mechanical hand and moisture content detection probe to contact with the surface of measured saw material vertically or parallel to the texture direction of surface of measured saw material, measures the moisture content of saw material point by point;According to the measurement result, the average of each point is the moisture content of this root / piece measured saw material;And the measurement result is sprayed on measured saw material.The present application compared with traditional saw material moisture content measurement method, measurement precision is high, work efficiency is strong, labor intensity is low, can promote subsequent processing process product quality, help timber processing enterprise optimization and upgrading.

Description

Technical Field

[0001] This invention relates to a method and production line for online automatic measurement of the moisture content of sawn timber. This invention belongs to the field of wood processing technology. Background Technology

[0002] Sawn timber moisture content generally refers to the final percentage of moisture content in dried sawn timber. The detection of sawn timber moisture content is crucial in wood processing and applications. The range of moisture content significantly affects the physical and mechanical properties of sawn timber, and excessively high or low moisture content can easily lead to quality defects in wood products. Therefore, accurate detection of sawn timber moisture content during sawing is a key factor in ensuring the quality and processing effect of finished wood products.

[0003] The traditional method for testing the moisture content of sawn timber is as follows: Sawn timber is randomly selected from a batch according to a standard proportion. Moisture content test pieces are cut from both ends and within a specified range in the middle of the entire piece of timber and weighed. These test pieces are then placed in a drying oven and dried to absolute dryness. The moisture content is calculated using the weight difference between the two states. The average moisture content of the selected pieces represents the final moisture content of the entire batch. The disadvantages of this method are: 1. Low representativeness of the test results. The moisture content of each sawn timber in a batch varies, and the test cannot completely cover every piece. The traditional method of randomly selecting a few pieces to represent the average moisture content of the entire batch results in a large measurement error, making it difficult to determine the actual moisture content range. 2. The traditional method is inefficient, time-consuming, and energy-intensive, making it unsuitable for processing enterprises. Manual testing is time-consuming, labor-intensive, costly, and has low cost-effectiveness. It is prone to errors, leading to a high defect rate in finished products. 3. When different types of sawn timber from the same batch are measured together, the measurement results will affect the accuracy of the final moisture content determination. The ratio of heartwood to sapwood and the grain direction on the same sawn timber will also affect the accuracy of the moisture content determination. In addition, wood itself has anisotropy, and traditional testing methods cannot avoid these inherent characteristics affecting the accuracy of moisture content measurement results. Summary of the Invention

[0004] To address the shortcomings of traditional methods for measuring the moisture content of sawn timber, the present invention aims to provide an online automatic production line for measuring the moisture content of sawn timber that can quickly and accurately measure the moisture content of each piece / piece of sawn timber, with high measurement efficiency and low labor intensity.

[0005] Another objective of this invention is to provide a method for measuring the moisture content of sawn timber that can quickly and accurately measure the moisture content of each piece / sheet of sawn timber, with high measurement efficiency and low labor intensity.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: an online automatic measurement method for the moisture content of sawn timber, namely:

[0007] S1. Build a production line that can automatically transport the sawn timber to be tested. Install a high-definition camera at the entrance of the production line to capture the surface texture of the sawn timber to be tested, and install a robotic arm on the production line to fix the moisture content detection probe.

[0008] S2, the sawn timber to be tested is dried and then left to stand for at least half a month;

[0009] S3: Input parameters such as tree species, length, width, and thickness of the sawn timber to be tested through the human-machine interface of the production line, start the production line, and transfer the sawn timber to be tested one piece / piece at a time.

[0010] S4, Identify the grain direction of the sawn timber and determine the measurement method;

[0011] The control unit activates the high-definition camera to capture images of the surface of each piece / sheet of sawn timber and receives the image data captured by the high-definition camera. Based on the images, it quickly identifies the type of sawn timber being tested. For sapwood, the moisture content detection probe is positioned perpendicular to the grain direction of the sawn timber surface being tested; for heartwood, the moisture content detection probe is positioned along the grain direction of the sawn timber being tested.

[0012] S5. Measurement of moisture content

[0013] Start the robotic arm and bring the moisture content detection probe fixed on the top of the robotic arm into contact with the surface of the sawn timber being tested, perpendicular or parallel to the surface texture of the sawn timber. Measure the moisture content of the sawn timber point by point from one end to the other. Then, the control unit calculates the average value of the measured values ​​based on the measurement results. The result is the moisture content of this piece / piece of sawn timber being tested.

[0014] S6. Data processing, recording, storage, and printing the measurement results onto the sawn timber being tested.

[0015] Preferably, two points located one-quarter of the distance from the front and rear ends of the sawn timber being measured are designated as measurement points for measurement.

[0016] An online automatic measurement production line for sawn timber moisture content includes a frame, a conveyor roller table, a slide, a high-definition camera, a robotic arm, a moisture content detection probe, an inkjet printer, and a control unit.

[0017] The transfer roller table is mounted and fixed on the top of the frame, and it includes a motor and several spaced rollers;

[0018] A slide rail parallel to the conveyor roller table is installed and fixed at the lower part of the frame. At least two robotic arms are mounted on the slide rail via sliders, and each robotic arm is equipped with a moisture content detection probe.

[0019] At the starting end of the transmission roller table, a high-definition camera for capturing the texture of the sawn timber being tested is fixed on the frame;

[0020] The inkjet printer is installed at the end of the transfer roller table;

[0021] The control unit includes a microprocessor, a touch screen, and several displacement sensors installed at different positions on the conveyor roller table. The data input terminal of the microprocessor is connected to the data output terminal of the moisture content detection probe, the data output terminal of the high-definition camera, and the data output terminals of each displacement sensor via wired or wireless means to transmit data. The control signal output terminal of the microprocessor is connected to the control terminal of the robot arm and the control terminal of the inkjet printer to control their actions.

[0022] Preferably, a lifting device for raising and lowering the slide is also installed on the columns at both ends of the frame.

[0023] Preferably, a supplementary light source is also provided next to the high-definition camera on the frame.

[0024] This invention enables continuous online measurement of sawn timber moisture content, providing real-time display of moisture content measurement results and inkjet marking functionality. Compared with traditional sawn timber moisture content measurement methods, it offers higher measurement accuracy, greater work efficiency, and lower labor intensity, significantly improving the quality of finished products in subsequent processing steps and assisting large-scale woodworking enterprises in optimization and upgrading. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the online automatic moisture content measurement production line for sawn timber according to the present invention. Detailed Implementation

[0026] The structure and features of the present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that various modifications can be made to the embodiments disclosed herein; therefore, the embodiments disclosed in this specification should not be considered as limitations on the present invention, but merely as examples to make the features of the present invention readily apparent.

[0027] like Figure 1 As shown, the online automatic moisture content measurement production line for sawn timber of the present invention includes a frame 1, a transmission roller table 2, a slide rail 3, a high-definition camera 4, a robotic arm 5, a moisture content detection probe 6, an inkjet printer 7, and a control unit 8.

[0028] The transfer roller table 2 is mounted and fixed on the top of the frame 1. It includes a motor and several spaced rollers 21. Driven by the motor, the rollers 21 rotate, transferring the sawn timber 9 to be tested placed on them from one end of the frame to the other end.

[0029] A slide rail 3 parallel to the conveyor roller table is fixedly installed at the lower part of the frame 1. At least two robotic arms 5 are mounted on the slide rail via sliders 12, and each robotic arm is equipped with a moisture content detection probe 6. Under the control of the control unit 8, the robotic arms 5 slide along the slide rail 3 and drive the moisture content detection probe 6 to contact the surface of the sawn timber 9 being tested, measuring the moisture content of the sawn timber. The data output terminal of the moisture content detection probe 6 is connected to the control unit 8 via wired or wireless means to transmit data.

[0030] At the starting end of the conveyor roller table 2, a high-definition camera 4 is fixed on the frame to capture the surface texture of the sawn timber 9 being tested on the conveyor roller table. The data output end of the high-definition camera 4 transmits the captured images to the control unit 8 via wired or wireless means, which is used to determine the contact method between the moisture content detection probe 7 and the sawn timber being tested.

[0031] The control unit 8 includes a microprocessor, a touch screen, and displacement sensors mounted at different positions on the conveyor roller table 2. The image data output terminal of the high-definition camera 4 transmits data to the microprocessor via wired or wireless means. The microprocessor determines the type of sawn timber being tested based on the captured image of the sawn timber surface texture. The signal output terminal of the displacement sensor transmits data to the microprocessor via wired or wireless means so that the microprocessor can control the movement position of the sawn timber being tested. The control signal output terminal of the microprocessor is connected to the control terminal of the robot arm 5 via wire 13 to control the movement of the robot arm and drive the robot arm to contact the moisture content detection probe with the sawn timber being tested to measure the moisture content of the sawn timber, and to receive the measurement data from the moisture content detection probe.

[0032] At the end of the frame 1, a laser marking device 7 is also installed. Its control terminal is connected to the microprocessor control signal output terminal. The microprocessor controls the marking device 7 to directly spray the measurement results onto the sawn timber being measured, so that they can be read during subsequent operations.

[0033] The microprocessor can also display the measurement results directly on the touch screen.

[0034] like Figure 1As shown, the present invention also includes a lifting device 10 for raising and lowering the slide rail 3 installed on the left and right end columns of the frame 1 to adjust the distance between the robotic arm 5 and the sawn timber 9 being tested. The control unit 8 outputs a control signal to drive the lifting device 10 to raise the slide rail 3 to a certain height, so that the distance between the robotic arm 5 and the moisture content detection probe 6 on it and the sawn timber 9 being tested is shorter, thus improving measurement efficiency. The lifting device 10 for raising and lowering the slide rail 3 can be hydraulic, electric, or pneumatic. In a preferred embodiment of the present invention, the lifting device 10 for raising and lowering the slide rail is an electric lifting mechanism, which includes a servo motor 101 and a lead screw 102 mounted on the frame. The output shaft of the servo motor is connected to the lead screw through a coupling. Under the control of the control unit, the servo motor drives the lead screw to move up and down, thereby raising or lowering the slide rail 3.

[0035] like Figure 1 As shown, in order to make the images captured by the high-definition camera 4 clearer, the present invention also provides a supplementary light source 11 next to the high-definition camera.

[0036] The above-mentioned online sawn timber moisture content measurement production line can quickly and accurately measure the moisture content of each piece / sheet of sawn timber online. The specific method is as follows:

[0037] 1. Dry the sawn timber and let it stand for at least half a month after drying.

[0038] Before processing, sawn timber needs to be dried to the required equilibrium moisture content and then stored in a cool, shaded place for at least half a month. The purpose is to maintain the equilibrium moisture content of the sawn timber within a stable range. This is because after the initial drying, the moisture content of the sawn timber decreases significantly, but the wood itself will absorb moisture. If the dried sawn timber is processed directly, it can lead to problems such as cracking and warping in the finished wood product. Therefore, it is essential to let the sawn timber stand for at least half a month after drying until the equilibrium moisture content stabilizes before measuring the moisture content. The subsequent processing procedures should then be initiated based on the measurement results. This method of measuring the moisture content of the sawn timber is therefore more meaningful.

[0039] 2. Input the sawn timber parameters and start the production line.

[0040] Through the human-machine interface of the production line, parameters such as timber species, timber length, timber width, timber thickness, and timber density are input so that the control unit can output control signals to control the operation of the transmission roller table and the moisture content detection probe.

[0041] 3. Identify the grain of the sawn timber to determine the measurement method.

[0042] The control unit activates a high-definition camera to capture images of the surface of each sawn timber and receives the image data captured by the high-definition camera. Based on the images, it quickly identifies the type of sawn timber being tested, whether it is sapwood or heartwood, thereby determining the measurement method.

[0043] Sawn timber itself contains not only wood grain patterns but also numerous vessels and resin ducts. During the sawn timber drying process, surface moisture evaporates first, while internal moisture conduction relies primarily on microcapillaries and macrocapillaries. Many factors influence moisture conduction; for example, the heartwood's moisture conduction is generally lower than the sapwood's, resulting in a difference in moisture content between the two. Therefore, the location of moisture content testing is crucial for the accuracy of the measurement results.

[0044] Through continuous exploration, the applicant of this invention discovered that for sapwood, the grain spacing is large and the grain is irregular, and the moisture channels are numerous and dense, so it is necessary to measure perpendicular to the grain direction; for heartwood, although the grain is clear, the moisture channels are sparse, few and fine, and not easy to find, so it is more accurate to measure along the grain direction.

[0045] 4. Measurement of moisture content

[0046] Start the robotic arm and bring the moisture content detection probe fixed on the top of the robotic arm into contact with the surface of the sawn timber being tested, perpendicular or parallel to the wood grain. Measure the moisture content of the sawn timber point by point from one end to the other. Then, the microprocessor calculates the average value of the measured values ​​at each point based on the measurement results. The calculated result is the moisture content of this piece / piece of sawn timber being tested.

[0047] Practice has shown that the moisture content value at 1 / 4 of the distance from the end face of the sawn timber is closest to the final measured value of the moisture content of the sawn timber. Therefore, two points at 1 / 4 of the distance from the front and rear ends of the sawn timber can be selected as measurement points for rapid measurement.

[0048] In the actual measurement process, the conveyor roller table sequentially transports the individual sawn timbers to be measured, which can effectively avoid the influence of other sawn timbers on the results.

[0049] To reduce measurement error, multiple measurements can be taken at the same location. After removing the maximum and minimum values, the average value is taken as the actual value.

[0050] 5. Process, record, and store the data, and then print the measurement results on the sawn timber being tested.

[0051] To facilitate subsequent processing, the control unit of this invention outputs a control signal to start the inkjet printer and directly print the measurement results onto the surface of the sawn timber being tested.

[0052] The measurement results can also be displayed in real time via a digital touch screen. Unqualified or substandard products will be highlighted. After the measurement is completed, the stored data can be exported to an external storage device as needed.

[0053] This invention enables rapid and accurate online measurement of the moisture content of each piece of sawn timber, meeting the modern demand for automation and informatization in sawn timber moisture content measurement. It improves the informatization and automation level of solid wood sawn timber manufacturing and ensures product quality in subsequent processing steps.

[0054] Finally, it should be noted that the above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for online automatic measurement of moisture content in sawn timber, characterized in that: S1. Build a production line that can automatically transport the sawn timber to be tested. Install a high-definition camera at the entrance of the production line to capture the surface condition of the sawn timber to be tested. Install a robotic arm on the production line to fix the moisture content detection probe. S2, the sawn timber to be tested is dried and then left to stand for at least half a month; S3: Input the tree species, length, width, and thickness parameters of the sawn timber to be tested through the human-machine interface of the production line, start the production line, and transmit the sawn timber to be tested one piece / piece at a time. S4, Identify the grain direction of the sawn timber and determine the measurement method; The control unit activates the high-definition camera to capture images of the surface of each piece / sheet of sawn timber and receives the image data captured by the high-definition camera. Based on the images, it quickly identifies whether the sawn timber being tested is sapwood or heartwood. For sapwood, the moisture content detection probe is positioned perpendicular to the grain direction of the sawn timber surface to take the measurement. For heartwood, the moisture content detection probe is positioned along the grain direction of the sawn timber surface to take the measurement. S5, Measurement of moisture content Start the robotic arm so that the moisture content detection probe fixed on the top of the robotic arm comes into contact with the surface of the sawn timber being tested. Then, according to the direction determined in S4, measure the moisture content of the sawn timber point by point from one end to the other. The control unit then calculates the average value of the measured values ​​at each point based on the measurement results. The result is the moisture content of this piece / piece of sawn timber being tested. S6 processes, records, and stores data, and prints the measurement results onto the sawn timber being tested. The point-by-point measurement includes: defining two points located 1 / 4 of the distance from the front and rear ends of the sawn timber being measured as measurement points for measurement.

2. An online automatic moisture content measurement production line for sawn timber, used to implement the method as described in claim 1, characterized in that: It includes a frame, a conveyor roller table, a slide, a high-definition camera, a robotic arm, a moisture content detection probe, an inkjet printer, and a control unit; The transfer roller table is mounted and fixed on the top of the frame, and it includes a motor and several spaced rollers; A slide rail parallel to the conveyor roller table is installed and fixed at the lower part of the frame. At least two robotic arms are mounted on the slide rail via sliders, and each robotic arm is equipped with a moisture content detection probe. At the starting end of the transmission roller table, a high-definition camera for capturing the surface texture of the sawn timber being tested is fixed on the frame; The inkjet printer is installed at the end of the transfer roller table; The control unit includes a microprocessor, a touch screen, and several displacement sensors installed at different positions on the conveyor roller table. The data input terminal of the microprocessor is connected to the data output terminal of the moisture content detection probe, the data output terminal of the high-definition camera, and the data output terminals of each displacement sensor via wired or wireless means for data transmission. The control signal output terminal of the microprocessor is connected to the control terminal of the robot and the control terminal of the inkjet printer to control their actions. The robot is configured to receive instructions from the microprocessor and drive the moisture content detection probe to contact the sawn timber perpendicular to or parallel to the surface texture direction of the sawn timber being tested.

3. The sawn timber moisture content online automatic measurement production line according to claim 2, characterized in that: A lifting device for raising and lowering the slide is also installed on the columns at both ends of the frame.

4. The online automatic moisture content measurement production line for sawn timber according to claim 3, characterized in that: A supplementary light source is also installed next to the high-definition camera on the rack.

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