Method for online testing thickness of foam material through X rays

Abstract

The invention relates to a method for online testing the thickness of a foam material through X rays. The method mainly solves the problems that in the prior art, online measurement of the thickness of soft materials such as sponge, composite leather and composite sponge is difficult to detect, and precision is poor. The novel method for testing the thickness of the foam material on line through the X rays comprises the steps that 1, a system is started; 2, data are input; 3, online detection; 4, an operator monitors related data in real time, and if the data exceeds the standard, an alarm gives an alarm, and shutdown detection is judged; 5, after the measurement is finished, the operator saves the measurement data to the cloud, checks whether the equipment is abnormal or not, and closes the equipment; wherein when the foam material moves on line to pass through the detection platform, the foam material needs to be kept in a stable and tight state. The problems are well solved, and the method can be applied to the sponge industry, the composite leather industry and the composite sponge industry.

Description

Technical Field

[0001] The present invention relates to a method for on-line measuring the thickness of foam materials by X-ray. Background Art

[0002] Modern consumers' expectations for the quality of automotive interiors are constantly rising. They not only focus on the aesthetics and comfort, but also put forward strict requirements in terms of environmental protection, durability, safety, etc. of the products. To meet the needs of consumers, vehicle manufacturers have put forward more stringent standards for the processing level of automotive interior composite materials. This includes strict control over aspects such as the surface quality, dimensional accuracy, and physical properties of the materials. The traditional processing technology of automotive interior composite materials has many limitations and can no longer meet the increasingly upgraded customer needs. It is necessary to introduce more competitive new processes and equipment.

[0003] An X-ray thickness gauge is a thickness measurement device based on the principle of X-ray penetration. When X-rays pass through a substance, their intensity will decrease due to factors such as absorption and scattering by the substance. The greater the thickness of the substance, the stronger the absorption effect on X-rays, and the lower the intensity of the transmitted X-rays. Therefore, by measuring the intensity of the transmitted X-rays, the thickness of the substance can be deduced. Therefore, an on-line thickness measurement device composed of X-rays can measure a variety of materials by matching the conversion formulas for each material. And because it measures the attenuation degree of the rays after passing through the material, the X-rays are not affected by the surface state of the material and have high accuracy and repeatability accuracy. Among them, the accuracy is below 0.0001 mm and the repeatability accuracy is below 0.001 mm. In actual production, the X-ray on-line thickness gauge consists of an upper X-ray source platform, a lower X-ray receiving source platform, a motor, a transmission roller device, a signal processing device, a control panel, etc. Cooperating with the automated transmission line for the production products, the on-line thickness measurement of sponge, composite leather, and composite sponge can be achieved.

[0004] Chinese Patent CN212620595U discloses a thickness automatic detection device. This invention mainly solves the technical problems in the prior art, such as large errors in manually measuring the thickness of products, untimely product detection leading to an increase in defective products and missed inspections, and the inability to effectively trace and analyze when product thickness problems occur, and provides a new device for automatically detecting thickness. By adopting the technical solution including a base 1, a guide roller 2, a reference roller 3, a base material 4, a motor 5, a data transmission line 6, and a host 7, this technical problem is better solved and can be used in the industrial production of automotive composite materials. However, in principle, a triangular displacement laser sensor calculates the geometric data of the actual displacement by the laser receiver receiving the laser emitted by the laser emitter and reflected from the surface of the object to be measured. Due to the linear propagation of the laser, it has high requirements for the surface flatness and smoothness of the object to be measured. Most automotive composite materials are soft materials, and their surfaces are relatively uneven, such as the fluff of non-woven fabrics and the holes of sponges. Moreover, the triangular displacement laser sensor applies the principles of light reflection and geometry and has high requirements for the stability of the mechanism. It has good performance in static environments such as laboratories, but during online production on the production line, the measurement results often deviate greatly due to the vibration and movement of the mechanism and the product. Therefore, it can be seen that the laser online thickness measurement device has a narrow application range and a large deviation in repeatability accuracy. Among them, the accuracy is below 0.005 mm, but the repeatability accuracy is above 0.08 mm, which has great limitations in actual production applications. Summary of the Invention

[0005] The technical problem to be solved by the present invention is the difficulty in detecting and poor accuracy in online thickness measurement of soft materials such as composite leather, sponge, and composite sponge. A new method for online testing the thickness of foam materials by X-ray is provided. This device has the advantages of being convenient for testing sponges, composite leather, and composite sponges and high testing accuracy.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A method for online testing the thickness of foam materials by X-ray, including the following steps:

[0007] Step 1: Start the system, run the X-ray online thickness gauge, and calibrate the thickness range required for the material;

[0008] Step 2: Take a sample of the foam material, test the thickness level of the foam material according to the corresponding industry test standard, and input it into the operation platform library of the online thickness gauge for:

[0009] The curve points corresponding to the particle loss rate after X-rays penetrate an object. The foam material is a new material with relatively uniform density. Then the starting curve graph is an equi-proportional straight line, and the subsequent measurement data will form a database, further filling in the specific particle loss rates for each thickness to form a more accurate curve. The corresponding thickness can be directly obtained according to the curve points. For the new material with uniform thickness, experiments have proved that the intensity attenuation of X-rays after penetrating a substance is proportional to the distance the rays pass through in the substance; the intensity of the incident rays is I0, entering a uniform-density absorber, and its intensity at x is Ix. When passing through a thickness dx, the intensity attenuation is dI. Defining μ as the ratio of X-rays absorbed per unit thickness, then: -dI = μ·Ix·dx. Considering the boundary conditions and integrating, we get: Ix = I0 e-μx, where μ is called the linear attenuation coefficient and x is the specimen thickness;

[0010] Step 3: The foam material is moved online through the rollers of the production line and conveyed onto the feeding guide roller 3-1, discharging guide roller 3-2, feeding reference roller 4-1, and discharging reference roller 4-2, passing between the X-ray emitting machine 1 and the X-ray receiving machine 2. The system collects the X-ray particle loss rate when the material passes through and converts it into the real-time material thickness x through the host computer;

[0011] Step 4: The operator monitors the relevant data in real time. If there is an over-standard data, the alarm will sound. The operator judges whether to stop the machine to detect the sample. If there is no abnormality, the continuous line production is normally completed;

[0012] Step 5: After the measurement is completed, the operator saves the measurement data to the cloud, checks whether there is any abnormality in the equipment, and then shuts down the equipment.

[0013] Among them, when the foam material moves online through the detection platform, the foam material should be kept in a stable and taut state.

[0014] In the above solution, preferably, the feeding guide roller 3-1 and the discharging guide roller 3-2 are arranged horizontally and parallel to each other, the feeding reference roller 4-1 and the discharging reference roller 4-2 are arranged horizontally and parallel to each other, the weights of the feeding reference roller 4-1 and the discharging reference roller 4-2 are kept consistent, and the mechanism pressure foot 10 is fixed to the whole machine by bolts and nuts or the fixing mechanism is made of marble.

[0015] In the above technical solution, preferably, the irregular jitter of the feeding is controlled by the feeding reference roller 4-1 and the discharging reference roller 4-2. The feeding guide roller 3-1 and the discharging guide roller 3-2 adjust the feeding tension and stability according to the feeding speed. A tension controller is placed inside the chassis between the two guide rollers. After receiving the signal from the force sensor, it will adjust the tension in real time to change the incoming state of the detected material. The roller has been dynamically balanced and is made of steel structure to reduce the deformation of the material movement. The surface is electroplated to ensure flatness and uniform friction. The main structure of the machine platform is made of marble table to reduce the feeding jitter.

[0016] In the above solution, preferably, the foam material is sponge, composite leather, or composite sponge.

[0017] In the present invention, the non-contact measurement is realized by the X-ray transmission method. After the X-ray beam generated by the X-ray emitting machine 1 penetrates the test substrate 12, the X-ray receiving machine 2 calculates the thickness value in real time through the detection of the particle number loss. The control system ensures the measurement accuracy through the following technologies:

[0018] 1. Dynamic compensation system: The slide-screw mechanism realizes the synchronous positioning of the emission / reception unit;

[0019] 2. Vibration suppression design: The feeding reference roller 4-1 and the discharging reference roller 4-2 are equipped with buffer structures to ensure that the amplitude is ≤0.05 mm under high-speed conditions;

[0020] 3. Environment optimization: The dust removal pipe 11 maintains the cleanliness of the measurement area. The mechanism pressure foot 10 fixes the balance of the whole machine through bolts and nuts, or the fixing mechanism is made of marble to make the pressure foot mechanism provide mechanical stability at the level of ±0.1 mm.

[0021] The present invention realizes the compatibility of the measurement accuracy of 0.01 mm level and the line speed of 120 m / min through the mechatronic design, and the efficiency is increased by more than 300% compared with the traditional contact thickness measuring device; and during the production process, the data is accumulated and analyzed through the cloud platform, and calibrated with the laboratory test data for correction, which can further correct the deviation value of the data and obtain accurate measurement data. Brief Description of the Drawings

[0022] Att Figure 1 is a schematic diagram of the X-ray on-line thickness measuring device;

[0023] Att Figure 2 is a structural diagram of the X-ray emitting machine;

[0024] Att Figure 3 is a structural diagram of the X-ray receiving machine;

[0025] Att Figure 4 is a side view of the X-ray on-line thickness measuring device;

[0026] Appendix Figure 5 、 6 Figures 6 and 7 are the result charts of different products tested in the present invention, with laser and measured values;

[0027] Among them, 1 is an X-ray emission machine, 2 is an X-ray receiving machine, 3-1 is a feed guide roller, 3-2 is a discharge guide roller, 4-1 is a feed reference roller, 4-2 is a discharge reference roller, 5 is a linkage shaft, 6 is a connecting rod, 7 is an alarm, 8 is a control panel, 9 is a chassis frame, 10 is a mechanism presser foot, 11 is a dust removal pipe, 12 is a test substrate, 1-1 is a first drag chain, 1-2 is a first slide rail, 1-3 is a first fixing rod, 1-4 is a first lead screw, 1-5 is an X-ray sensor; 2-1 is a second drag chain, 2-2 is a second slide rail, 2-3 is a second fixing rod, 2-4 is a second lead screw, 2-5 is an X-ray receiver. Detailed implementation manners

[0028]

Example 1

[0029] An X-ray on-line thickness measuring device, comprising: an X-ray emitting machine 1, an X-ray receiving machine 2, a feed guide roller 3-1, a discharge guide roller 3-2, a feed reference roller 4-1, a discharge reference roller 4-2, a linkage shaft 5, a connecting rod 6, a control panel 8, a chassis frame 9, a mechanism pressure foot 10, and a test substrate 12. Among them, the X-ray emitting machine 1 includes a first drag chain 1-1, a first slide rail 1-2, a first fixed rod 1-3, a first lead screw 1-4, and an X-ray sensor 1-5; the X-ray receiving machine 2 includes a second drag chain 2-1, a second slide rail 2-2, a second fixed rod 2-3, a second lead screw 2-4, and an X-ray receiver 2-5; both the X-ray emitting machine 1 and the X-ray receiving machine 2 are fixed on the chassis frame 9. The X-ray emitting machine 1 is integrated in the upper frame part of the chassis frame 9, and the X-ray receiving machine 2 is integrated in the lower frame part of the chassis frame 9. Their positions are kept in real-time consistent through an integrated control system; the feed guide roller 3-1 and the discharge guide roller 3-2 are installed in the upper grooves of the left and right frames for feeding and discharging; the feed reference roller 4-1 and the discharge reference roller 4-2 are installed in the lower grooves of the left and right frames; the linkage shaft 5 is between the groove and the connecting rod 6, responsible for delivering the torque of the motor inside the chassis frame 9 to the connecting rod 6 to drive the feed guide roller 3-1, the discharge guide roller 3-2, the feed reference roller 4-1, and the discharge reference roller 4-2; the control panel 8 is connected to the built-in host through a wire harness for human-computer interaction and data supervision; the test substrate 12 passes through the feed guide roller 3-1, the discharge guide roller 3-2, the feed reference roller 4-1, and the discharge reference roller 4-2 in the direction shown by the line. It is characterized in that the mechanism pressure foot 10 is fixed to the whole machine or the fixing mechanism by bolts and nuts and is made of marble. The feed guide roller 3-1 and the discharge guide roller 3-2 are horizontally parallel, the feed reference roller 4-1 and the discharge reference roller 4-2 are horizontally parallel, and the weights of the feed reference roller 4-1 and the discharge reference roller 4-2 are kept consistent.

[0030] The first slide rail 1-2 and the first lead screw 1-4 are both fixed inside the chassis frame 9. The upper end of the inner side of the first fixed rod 1-3 is fixedly connected to the other end of the first drag chain 1-1. The first drag chain 1-1 drives the X-ray sensor 1-5 to make a reciprocating motion set by the host program on the first fixed rod 1-3 under the drive of the motor; the second slide rail 2-2 and the second lead screw 2-4 are both fixed inside the chassis frame 9. The upper end of the inner side of the second fixed rod 2-3 is fixedly connected to the other end of the second drag chain 2-1. The second drag chain 2-1 drives the X-ray receiver 2-5 to make a reciprocating motion set by the host program on the second fixed rod 2-3 under the drive of the motor.

[0031] The sensing head of the X-ray emission machine 1 described above uses a 30 Kev X-ray emitter and a gas ionization chamber / solid ionization detector. Such a sensing head can generate high-intensity X-ray particles, which can penetrate relatively thick materials, and the sampling distance can exceed 11 mm. Using a high-speed linear motor, the line scan speed can be 60 m / min, the sampling frequency is 200 KHz, the spot coverage is 3.2 * 38 mm, and the overall thickness gauge frame width is 2.2 m.

[0032] Step 1: Start the system, run the X-ray online thickness gauge, and calibrate the thickness range required by the material.

[0033] Step 2: Take a sample of the foam material and test the thickness level of the foam material using the corresponding industry test standard, and input it into the operation platform library of the online thickness gauge for:

[0034] The curve points corresponding to the particle loss rate after X-rays penetrate an object. The foam material is a new material with relatively uniform density, so the starting curve graph is a proportional straight line, and the subsequent measurement data will form a database, further filling in the specific particle loss rates at each thickness to form a more accurate curve. According to the curve points, the corresponding thickness can be directly obtained. For a new material with uniform thickness, experiments have shown that the intensity attenuation of X-rays after penetrating a substance is proportional to the distance the rays pass through in the substance. The intensity of the incident rays is I0, entering a uniform-density absorber, and its intensity at x is Ix. When passing through a thickness dx, the intensity attenuation is dI. Defining μ as the ratio of X-rays absorbed per unit thickness, then: -dI = μ·Ix·dx. Considering the boundary conditions and integrating, we get: Ix = I0 e-μx, where μ is called the linear attenuation coefficient and x is the sample thickness.

[0035] Step 3: The foam material is conveyed online through the rollers of the production line to the feeding guide roller 3-1, the discharging guide roller 3-2, the feeding reference roller 4-1, and the discharging reference roller 4-2, passing between the X-ray emission machine 1 and the X-ray receiving machine 2. The system collects the X-ray particle loss rate when the material passes through, and converts it into the real-time material thickness x through the host computer.

[0036] Step 4: The operator monitors the relevant data in real time. If the alarm goes off for any exceeded standard data, the operator determines whether to stop the machine to inspect the sample. If there are no abnormalities, the continuous line production is completed normally.

[0037] Step 5: After the measurement is completed, the operator saves the measurement data to the cloud, checks whether there are any abnormalities in the equipment, and shuts down the equipment.

[0038] Among them, when the foam material moves online through the detection platform, the foam material should be kept in a stable and taut state.

[0039] In the above scheme, preferably, the feed guide roller 3-1 and the discharge guide roller 3-2 are arranged horizontally and parallel, the feed reference roller 4-1 and the discharge reference roller 4-2 are arranged horizontally and parallel, the weight of the feed reference roller 4-1 and the discharge reference roller 4-2 are consistent, and the mechanism presser foot 10 fixes the entire machine or the fixing mechanism is made of marble by bolts and nuts.

[0040] In the above scheme, preferably, the foam material is sponge, composite leather, or composite sponge.

[0041] The material is divided into nine equal-width areas according to the warp direction of the machine. The electric system controls the servo motor to pull the position of the sensor head and the receiving plate, and the movement speed and movement trajectory of the sensor are set to measure and organize the data of these nine partitions. When the operator starts the host to input the electrical signal, the machine will start the X-ray detector. At the same time, the servo motor pulls the sensor head and the receiving plate back and forth according to the set trajectory and speed, and measures the composite sponge, composite leather, and sponge. The data is collected and entered into the host display for real-time feedback. The data of the finished batch will be classified and saved in the host according to the batch number for subsequent reference and traceability. Different gradients of warning values ​​and corresponding measures are set in the system. For slight thickness deviations, the system can respond to them through automatic adjustment and manual reminders; for larger thickness deviations, the system will stop the line in time after the alarm to avoid losses.

[0042] The results of testing the thickness of the composite sponge, composite leather and sponge 1 of the present invention are shown in Table 1.

[0043] [Example 2]

[0044] Sponge 2 was used as the test sample, and the specific method was the same as in the above embodiment; the specific test results are shown in Table 2.

[0045] [Comparative Example 1]

[0046] Composite sponge, composite leather and sponge 1 were used as test samples, and the thickness was tested according to the steps of Chinese patent CN212620595U; the specific test results are shown in Table 1.

[0047] [Comparative Example 2]

[0048] Composite sponge, composite leather and sponge 1 were used as test samples. The measured values ​​of the samples were tested using an electronic thickness gauge. The measured values ​​can be defaulted to the actual values. It is specially used to measure the thickness of textiles. Principle: contact measurement. There is a force sensor on the probe. It stops immediately after contacting the object to ensure that the most accurate thickness value is measured without deformation force. The specific test results are shown in Table 1.

[0049] [Comparative Example 3]

[0050] Use the sponge 2 in Example 2 as the test sample, and detect the sponge thickness according to the steps of Chinese Patent CN212620595U; the specific detection results are shown in Table 2.

[0051]

Comparative Example 4

[0052] Use the sponge 2 in Example 2 as the test sample, according to the detection equipment of Chinese Patent CN212620595U, but only replace the laser with X-ray therein. The test results without fixing the mechanism presser foot and without setting the corresponding reference roller are shown in Table 2.

[0053]

Comparative Example 5

[0054] Use the sponge 2 in Example 2 as the test sample, and use X-ray to measure the thickness, but the test results without fixing only the frame are shown in Table 2.

[0055] Table 1 Thickness test results of products with different materials by different methods

[0056]

[0057]

[0058] Table 2 Thickness detection results of the same material by different test methods

[0059]

[0060] The above tests draw the conclusion that X-ray has the characteristics of high precision and high applicability scenarios, and can be used for on-line thickness detection of composite sponges, composite leathers, and sponges.

[0061] Figures 5 to 7 It is a chart formed according to Table 1. The measured values have been rounded to two decimal places after the decimal point. The data of the electronic thickness gauge can be approximated as the actual thickness value of the object. It can be seen from the figure that the product thickness results tested by the present invention are closer to the actual test results and can be flexibly applied to on-line production.

Claims

1. A method for online X-ray testing of foam material thickness, comprising the following steps: Step 1: Start the system, run the X-ray online thickness gauge, and calibrate the required thickness range of the material; Step 2: Take a sample of the foam material, test the thickness level of the foam material using the corresponding industry test standard, and input it into the operating platform library of the online thickness gauge for: The curve point corresponding to the particle loss rate after X-rays penetrate the object. The foam material is a new material with relatively uniform density. The initial curve graph is an equiproportional straight line. The subsequent measurement data will form a database, and further fill in the specific particle loss rate of each thickness to form a more accurate curve. The corresponding thickness can be directly obtained according to the curve point. For new materials with uniform thickness, experiments have shown that the intensity attenuation of X-rays after penetrating the material is proportional to the distance the ray passes through the material. The intensity of the incident ray is I0, and when it enters a uniform density absorber, its intensity at x is Ix. When it passes through a thickness dx, the intensity attenuation is dI. Define μ as the ratio of X-rays absorbed when passing through a unit thickness, then: -dI=μ·Ix·dx Considering the boundary conditions and integrating, we get: Ix=I0 e-μx, where μ is called the linear attenuation coefficient and x is the sample thickness. Step 3: The foam material moves online through the rollers of the production line and is transported to the feed guide roller (3-1), the discharge guide roller (3-2), the feed reference roller (4-1), and the discharge reference roller (4-2), and passes between the X-ray transmitting machine (1) and the X-ray receiving machine (2). The system collects the X-ray particle loss rate when the material passes through, and converts it into real-time material thickness x through the host; Step 4: The operator monitors the relevant data in real time. If there is an alarm for exceeding the data limit, the operator determines whether to stop the machine for testing samples. If there is no abnormality, the continuous line production is completed normally. Step 5: After the measurement is completed, the operator saves the measurement data to the cloud, checks whether the device has any abnormalities, and shuts down the device. When the foam material moves online through the detection platform, the foam material must remain stable and taut.

2. The method for online X-ray testing of foam material thickness according to claim 1, characterized in that: The feed guide roller (3-1) and the discharge guide roller (3-2) are arranged horizontally and in parallel, the feed reference roller (4-1) and the discharge reference roller (4-2) are arranged horizontally and in parallel, the weight of the feed reference roller (4-1) and the discharge reference roller (4-2) are kept consistent, the mechanism presser foot (10) is fixed by bolts and nuts, and the whole machine or the fixing mechanism is made of marble.

3. The method for online X-ray testing of foam material thickness according to claim 1, characterized in that: The foam material is sponge, composite leather or composite sponge.

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