A compression spot detection method

Abstract

This invention provides a method for detecting pressure marks. The testing process is as follows: S1, Equipment debugging: Turn on the constant temperature and humidity test chamber, adjust the temperature and humidity, and after the temperature and humidity stabilize and there is no condensation on the sample surface, proceed to the testing stage; S2, Sample arrangement: Place the pre-treated sample into the test chamber, and then cover the sample surface with packaging material and cushioning pad in sequence, ensuring that the packaging material is in close contact with the sample surface. Then, place an 8kg weight on top of the cushioning pad to simulate the gravitational compression effect during actual transportation; S3, Run under the test conditions set in S1, run continuously for the specified time, stop the test, and the test is completed. Using the method provided by this invention, the damage resistance performance of products in actual packaging and transportation environments can be predicted in advance, effectively reducing pressure mark transfer defects in finished products, reducing processing costs, and improving production efficiency, which has significant practical value.

Description

Technical Field

[0001] This invention relates to the field of steel plate coating technology, and specifically to a method for detecting pressure spots. Background Technology

[0002] During the production, packaging, and transportation of steel plate coated products (such as color coated plates), packaging materials (such as foam boards and plastic films) are in long-term contact with the surface of the steel plate. Under the influence of gravity and heat and humidity, the surface of the steel plate is prone to defects such as pressure marks and transfer marks. These defects directly affect the appearance of the product and are an important and intuitive basis for users to judge the quality of the product.

[0003] Currently, the testing of coated steel products focuses on the basic performance compliance of the coating during the production process, such as coating adhesion, corrosion resistance, and single damp heat aging performance. In laboratory testing, these performances are mainly tested based on single environmental factors or single material properties, without experimental simulation of the combined effects of packaging materials, gravity, and damp heat. As a result, the laboratory cannot simulate the stress state of the finished product during actual packaging and transportation, the contact of packaging materials, and the coupling effect of damp heat environment. Consequently, it is impossible to predict the performance of pressure mark transfer on the steel plate surface in advance. If such defects are only discovered after the finished product leaves the factory, not only is the handling process cumbersome, requiring additional manpower and resources for rework or replacement, increasing production costs, but it may also affect customer satisfaction, causing economic losses and damage to brand reputation. Summary of the Invention

[0004] In view of this, the present invention provides a method for detecting pressure marks, employing a non-condensing damp heat method. Through experimental equipment, sample preparation processes, and experimental procedures, it achieves precise laboratory testing of the pressure mark transfer performance of steel plate surfaces. Using the method provided by this invention, it is possible to simulate the synergistic effects of packaging materials, gravity, and damp heat in the laboratory, thereby enabling early prediction of the product's damage resistance in actual packaging and transportation environments. This effectively reduces pressure mark transfer defects in finished products, lowers processing costs, and improves production efficiency, demonstrating significant practical value.

[0005] The technical solution of the present invention is as follows: A method for detecting pressure spots, the testing process is as follows: S1, Equipment Debugging Turn on the constant temperature and humidity test chamber, adjust the temperature and humidity, and wait until the temperature and humidity are stable and there is no condensation on the sample surface before proceeding to the test stage; S2, Sample Layout The pre-treated sample was placed in the test chamber, and then the packaging material and cushioning pad were covered on the surface of the sample in sequence to ensure that the packaging material was in close contact with the surface of the sample. Then, an 8kg weight was placed on top of the cushioning pad to simulate the gravitational compression effect during actual transportation. S3, running Under the test conditions set in S1, run continuously for the specified time, then stop the test and the test is complete.

[0006] Preferably, in step S1, the temperature and humidity of the constant temperature and humidity test chamber are set using conventional settings or according to customer requirements.

[0007] Preferably, under normal settings, the temperature of the constant temperature and humidity test chamber is 50±2℃, and the relative humidity is not less than 95%.

[0008] Preferably, in step S3, the running time is set using a conventional setting or according to customer requirements.

[0009] Preferably, the running time is 120 hours under normal settings.

[0010] The preferred method for detecting pressure spots is as follows: Step 1: Experimental Apparatus and Materials The constant temperature and humidity test chamber mainly includes a heating device, a temperature and humidity measuring device, a temperature and humidity regulating device, and a forced ventilation system, ensuring that there is no condensation on the test surface during the test; Distilled or deionized water with a conductivity not exceeding 20 μS / cm should be used to avoid water impurities affecting the test results. Auxiliary materials: 100mm×80mm×20mm foam board to simulate packaging cushioning material; 8kg weight to simulate gravity compression during transportation; packaging materials; Step 2, Sample preparation and pretreatment Sample specifications: Test specimens with dimensions not less than 150mm×200mm, with a flat surface, free of oil stains, damage, and burrs on the edges, to avoid the initial state of the specimen affecting the test results; Pretreatment: Place the samples in an environment with a temperature of 23±2℃ and a relative humidity of 50±5% for at least 24 hours before testing to ensure that the samples are in a uniform condition; Step 3, Testing; Step 4, Result Evaluation After the test, the sample is removed. If there is no transfer mark on the sample surface, it is considered qualified; if there is a transfer mark, it is considered unqualified.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The pressure mark detection method provided by the present invention involves covering the sample surface with packaging material and buffer pad in sequence, and then pressing weights on the buffer pad to compress the sample under temperature and humidity control conditions. This realizes the simulation of accurate detection conditions for pressure mark to imprint defects on steel plate surface in the laboratory, filling the technical gap that existing detection methods cannot predict such defects in advance.

[0012] 2. Using the method of the present invention, products with unqualified pressure resistance performance can be screened out before leaving the factory, preventing defective products from entering the market, reducing the cost and cumbersome process of reworking and replacing finished products, and lowering production costs.

[0013] 3. The test process is standardized, easy to operate, and highly repeatable. It can effectively guide the optimization of production processes, improve the overall appearance quality of products, enhance user satisfaction, and significantly improve production and testing efficiency. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the pressure spot detection process.

[0016] Figure 2 This is a photo of the pressure mark detection process.

[0017] Figure 3 This is a photo of the results of the pressure mark detection test.

[0018] Figure 4 Photo 1 shows the pressure marks and transfer marks caused after the refrigerator was unpacked and transported.

[0019] Figure 5 Photo 2 shows the pressure marks and transfer marks caused after the refrigerator was unpacked and transported.

[0020] Figure 1 In the middle, 1-PE packaging plastic film, 2-weights, 3-foam board, 4-sample. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0022] In the following embodiments of the present invention, the constant temperature and humidity test chamber (model: GDS-500B, manufactured by Nanjing Wuhe Test Equipment Co., Ltd., with an accuracy of 0.01℃ / 0.1% and a measurement range of -20℃ to 150℃ / 30% to 98%) is used. The foam board is a rigid polyurethane foam, which is a high molecular polymer made from two core raw materials, polyisocyanate and polyol, through a foaming reaction. It is a commercially available product. The PE packaging plastic film comes from Aucma's customers and Midea's customers.

[0023] Example 1 Combination Figures 1-2 The present invention provides a method for detecting pressure spots, the specific process of which is as follows: Step 1: Experimental Apparatus and Materials The constant temperature and humidity test chamber mainly includes a heating device, a temperature and humidity measuring device, a temperature and humidity regulating device, and a forced ventilation system, ensuring that there is no condensation on the test surface during the test; Distilled water, with a conductivity of 15 μS / cm, meets the requirements; Auxiliary materials: 1 piece of foam board with dimensions of 100mm×80mm×20mm, 1 standard 8kg weight, and 1 sheet of PE packaging plastic film provided by the customer (Aucma); Step 2, Sample preparation and pretreatment Sample specifications: Select Aucma refrigerator color-coated sheet, cut into 150mm×200mm samples. The sample surface should be flat, free of oil stains, undamaged, and without burrs on the edges to avoid the initial state of the sample affecting the test results. Pretreatment: Place the samples in an environment with a temperature of 23℃ and a relative humidity of 50% for 24 hours before testing to ensure that the samples are in a uniform condition; Step 3, Testing S1, Equipment Debugging Turn on the constant temperature and humidity test chamber, set the temperature to 50℃ and the relative humidity to 96%, run for 30 minutes until the temperature and humidity stabilize and there is no condensation, then enter the test stage; S2, Sample Layout The pretreated sample was placed in the test chamber, and then PE packaging plastic film and foam board were covered on the surface of the sample in sequence to ensure that the packaging material was in close contact with the surface of the sample. Then, an 8kg weight was placed on the foam board. S3, running Under the test conditions set in S1, the test was completed after 120 hours of continuous operation. During the test, the temperature and humidity of the test chamber were observed regularly, and the sample surface was visually inspected for condensation to ensure that the parameters were stable. Step 4, Result Evaluation After the experiment, the sample was removed, and obvious transfer marks were observed on the surface with the naked eye. Figure 3 The batch of color-coated steel sheets was determined to have poor resistance to pressure marks, and indentations were likely to occur on the samples during transport. Using this template to transport an Aucma refrigerator (BCD-328WPNE) French four-door model resulted in dents on the refrigerator doors. (See attached image.) Figure 4 and Figure 5 .

[0024] Example 2 A method for detecting pressure spots, the specific process of which is as follows: Step 1: Experimental Apparatus and Materials The constant temperature and humidity test chamber mainly includes a heating device, a temperature and humidity measuring device, a temperature and humidity regulating device, and a forced ventilation system, ensuring that there is no condensation on the test surface during the test; The deionized water had a conductivity of 18 μS / cm, which meets the requirements. Auxiliary materials: 1 piece of foam board with dimensions of 100mm×80mm×20mm, 1 standard 8kg weight, and 1 sheet of PE packaging plastic film provided by Midea customer; Step 2, Sample preparation and pretreatment Sample specifications: Midea refrigerator color-coated sheet, order number: 250929034, material number: 10301002022331, refrigerator model: BCD-570WKPM (E), cut into 200mm×200mm samples. The sample surface is flat, free of oil stains, undamaged, and without burrs on the edges to avoid the initial state of the sample affecting the test results. Pretreatment: Place the samples in an environment with a temperature of 22℃ and a relative humidity of 54% for 24 hours before testing to ensure that the samples are in a uniform condition; Step 3, Testing S1, Equipment Debugging Turn on the constant temperature and humidity test chamber, set the temperature to 48℃ and the relative humidity to 95%, run for 30 minutes until the temperature and humidity stabilize and there is no condensation visible to the naked eye, then proceed to the test stage; S2, Sample Layout The pretreated sample was placed in the test chamber, and then PE packaging plastic film and foam board were covered on the surface of the sample in sequence to ensure that the packaging material was in close contact with the surface of the sample. Then, an 8kg weight was placed on the foam board. S3, running Under the test conditions set in S1, the test was completed after 100 hours of continuous operation. During the test, the temperature and humidity of the test chamber were observed regularly, and the sample surface was visually inspected for condensation to ensure that the parameters were stable.

[0025] Step 4, Result Evaluation After the test, the sample is removed. If there are no transfer marks on the sample surface, it is considered qualified. After using the sample to transport the refrigerator, there are no indentations on the surface.

[0026] Although the present invention has been described in detail with reference to preferred embodiments, it is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the scope of the claims.

Claims

1. A method of compression artifact detection, the method comprising: The testing process is as follows: S1, Equipment Debugging Turn on the constant temperature and humidity test chamber, adjust the temperature and humidity, and wait until the temperature and humidity are stable and there is no condensation on the sample surface before proceeding to the test stage; S2, Sample Layout The pre-treated sample was placed in the test chamber, and then the packaging material and cushioning pad were covered on the surface of the sample in sequence to ensure that the packaging material was in close contact with the surface of the sample. Then, an 8kg weight was placed on top of the cushioning pad to simulate the gravitational compression effect during actual transportation. S3, running Under the test conditions set in S1, run continuously for the specified time, then stop the test and the test is complete.

2. The compression artifact detection method of claim 1, wherein, In step S1, the temperature and humidity of the constant temperature and humidity test chamber are set using conventional settings or according to customer requirements.

3. The compression artifact detection method of claim 2, wherein, Under normal settings, the temperature of the constant temperature and humidity test chamber is 50±2℃, and the relative humidity is not less than 95%.

4. The method for detecting pressure spots as described in claim 2, characterized in that, In step S3, the running time is set either by standard settings or according to customer requirements.

5. The method for detecting pressure spots as described in claim 4, characterized in that, Under normal settings, the runtime is 120 hours.

6. The method for detecting pressure spots as described in claim 1, characterized in that, The specific process is as follows: Step 1: Experimental Apparatus and Materials The constant temperature and humidity test chamber mainly includes a heating device, a temperature and humidity measuring device, a temperature and humidity regulating device, and a forced ventilation system, ensuring that there is no condensation on the test surface during the test; Distilled or deionized water with a conductivity not exceeding 20 μS / cm should be used to avoid water impurities affecting the test results. Auxiliary materials: 100mm×80mm×20mm foam board to simulate packaging cushioning material; 8kg weight to simulate gravity compression during transportation; Packaging materials; Step 2, Sample preparation and pretreatment Sample specifications: Test specimens with dimensions not less than 150mm×200mm, with a flat surface, free of oil stains, damage, and burrs on the edges, to avoid the initial state of the specimen affecting the test results; Pretreatment: Place the samples in an environment with a temperature of 23±2℃ and a relative humidity of 50±5% for at least 24 hours before testing to ensure that the samples are in a uniform condition; Step 3, Testing; Step 4, Result Evaluation After the test, the sample is removed. If there is no transfer mark on the sample surface, it is considered qualified; if there is a transfer mark, it is considered unqualified.

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