[
    {
        "id": 1,
        "chunk": "PAPER • OPEN ACCESS",
        "category": " Abstract"
    },
    {
        "id": 2,
        "chunk": "# You may also like",
        "category": " References"
    },
    {
        "id": 3,
        "chunk": "# Solidification process analysis and parameter optimization of powder coating by electrostatic spraying  \n\nTo cite this article: Ran Yan etal2023 J.Phys.:Conf.Ser.2539 012092  \n\n- The characteristics of particle charging and deposition during powder coating processes with coarse powder Xiangbo Meng, Hui Zhang and Jingxu (Jesse) Zhu  \n\n- Study on the characterization technology of hiding power of powder coating Bing Xue, Ran Yan, Can Wang et al.  \n\n- Line balancing synchronization in powder coating workstation: A metal industry case study   \nF. H. Ho, M. Al-Haqeem Chee S. Abu and Y. L. Woo  \n\nView the article online for updates and enhancements.",
        "category": " References"
    },
    {
        "id": 4,
        "chunk": "# UNITED THROUGH SCIENCE & TECHNOLOGY",
        "category": " References"
    },
    {
        "id": 5,
        "chunk": "# Science + Technology + YOU!",
        "category": " Introduction"
    },
    {
        "id": 6,
        "chunk": "# 248th ECS Meeting Chicago, IL October12-16,2025 Hilton Chicago  \n\nSUBMIT ABSTRACTS by March28,2025",
        "category": " Abstract"
    },
    {
        "id": 7,
        "chunk": "# Solidification process analysis and parameter optimization of powder coating by electrostatic spraying  \n\nRanYana, Bing Xuea\\*, Yongyong Yuea  \n\na Jiangsu XCMG Construction Machinery Research Institute Co. Ltd., Xu Zhou, Jiangsu, China  \n\n\\*Corresponding author’s e-mail: xueb@xcmg.com  \n\nABSTRACT: Aiming at formulating reasonable curing process parameters of powder coating, solving the problems of over-drying of thin plate and impervious drying of the thick plate during combined drying of workpieces with different thicknesses, analyzing the optimal curing temperature range of powder coating by differential scanning calorimetry (DSC), and designing a three-factor and four-level DOE test scheme within the optimal curing temperature range to test the curing time of powder coating are necessary. Using Minitab analysis software, the significance of the influence of various factors on the powder curing time is verified and the powder coating curing process model is built on this basis. The results show that the furnace temperature and workpiece thickness have significant effects on the shortest and longest curing time of powder coating. And there is no obvious interaction between furnace temperature and heating rate. The curing process model based on this can effectively solve the drying problem of composite plates with different thicknesses and reduce energy consumption.",
        "category": " Abstract"
    },
    {
        "id": 8,
        "chunk": "# 1. INTRODUCTION  \n\nAs solvent-free solid powder environmentally friendly coating, powder coating has been widely used in various fields for its excellent coating performance, and powder electrostatic spraying has become one of the main surface treatment methods [1-3]. Different from solvent-based coatings, the curing of powder coatings needs to be carried out in the molten state and requires high-temperature curing. Generally, it needs to be at the substrate temperature of $180~^{\\circ}\\mathrm{C}$ for more than 15 minutes or at the substrate temperature of $200^{\\circ}\\mathrm{C}$ for more than 10 minutes to obtain a good curing effect. Moreover, the organic compounds in the powder coating formula are easy to be oxidized due to the influence of too high temperature or too long baking time, resulting in yellowing oxide and over-drying, which affects the consistency of coating quality [4,5]. And due to the economic and efficient characteristics of powder coating, the coating products gradually expand to thick plates and structural parts, but the heating rate of plates with different thicknesses and the maximum temperature of steel plates are different. If the same baking and curing conditions are adopted, it is easy to cause problems such as impermeability of thick plates and over-drying of thin plates, resulting in serious quality hidden dangers [6,7]. In the field of construction machinery, the workpiece structure is complex, and there are a large number of thin and thick plate composite structures [8], to ensure the complete curing and crosslinking reaction. It is necessary to set the appropriate curing temperature and curing process beat, and select reasonable thickness differences between thin and thick plate combinations, to avoid the decline of product paint film appearance quality caused by the problems of thick plate dryness and thin plate over-drying during the curing process of the powder paint film.  \n\nIn this paper, the non-isothermal curing reaction of powder coatings is analyzed by differential scanning calorimetry (DSC), and many curing process data of the production line are collected. A three-factor and four-level DOE test is designed to test the curing time in the laboratory, and Minitab analysis software is used to analyze the factors. The residual, main effect analysis and general linear fitting analysis are carried out on the test results of the shortest curing time, that is, the time just reaching the complete curing state, and the longest curing time, that is, the critical time of over-drying state. The influence degree of each factor on the curing time is determined, and the curing process model is constructed to guide the determination of the powder curing process of composite board.",
        "category": " Introduction"
    },
    {
        "id": 9,
        "chunk": "# 2. EXPERIMENTAL",
        "category": " Materials and methods"
    },
    {
        "id": 10,
        "chunk": "# 2.1 Materials and instruments  \n\nDSC 6000 differential scanning calorimeter; FCD-3000 oven; BYK color difference meter; Acetone, analytically pure; Polyester thermosetting powder coating, commercially available; Steel plate (150 $\\mathrm{mm}\\times70\\mathrm{mm}\\times2\\mathrm{mm}$ ).",
        "category": " Materials and methods"
    },
    {
        "id": 11,
        "chunk": "# 2.2 Experimental process",
        "category": " Materials and methods"
    },
    {
        "id": 12,
        "chunk": "# 2.2.1 The sample preparation  \n\nCommercial polyester thermosetting powder coating was sprayed on $150\\ \\mathrm{mm}\\times70\\ \\mathrm{mm}\\times0.2{\\sim}0.3\\ \\mathrm{mm}$ tinplate with film thickness between $60~{\\upmu\\mathrm{m}}{-}80~{\\upmu\\mathrm{m}}$ . Different oven temperatures were set and corresponding heating rates were controlled for curing.",
        "category": " Materials and methods"
    },
    {
        "id": 13,
        "chunk": "# 2.2.2 Determination of the shortest curing time and the longest curing time  \n\nStart timing after the furnace temperature rises to the set temperature, take out the cured paint film every 5min. Wipe the cured paint film with non-woven fabric dipped in acetone solution, and the non-woven fabric has no sticky color, that is, it is completely cured, and the record that the curing time at this time is the shortest curing time. Taking the standard color board as the standard, the color difference of the cured paint film is tested by the BYK color difference instrument. The color difference $\\leq1.5$ is considered as the critical point of the over-drying of the paint film, and the curing time when the color difference of the paint film is more than 1.5 is recorded as the longest curing time.",
        "category": " Materials and methods"
    },
    {
        "id": 14,
        "chunk": "# 2.2.3 Testing and Characterization  \n\nDifferential scanning calorimetry (DSC) was used to measure the optimum curing temperature range of industrial polyester thermosetting powder coating under programmed temperature control. The temperature rise rate was $10\\ {^{\\circ}\\mathrm{C/min}}$ and the temperature rise range was $20^{\\circ}\\mathrm{C}{-}300^{\\circ}\\mathrm{C}$ .  \n\nWithin the optimum curing temperature range of powder coating, based on the thickness of commonly used workpieces in the field of construction machinery and the current situation of coating production lines of various companies, the full factor test is designed by DOE. The furnace temperature, heating rate, and steel plate thickness are set as independent variables, and the shortest curing time and the longest curing time are set as dependent variables. The test scheme is shown in Table 1.  \n\nTable 1. Test design factor coding level.   \n\n\n<html><body><table><tr><td>Factor</td><td>Encoding</td><td>Number of levels</td><td colspan=\"3\">The level of value</td></tr><tr><td>Furnace temperature /°C</td><td>A</td><td>3</td><td>180 200</td><td>220</td><td>/</td></tr><tr><td>Temperature rate/ (C·min-1)</td><td>B</td><td>3</td><td>8</td><td>15 20</td><td>/</td></tr><tr><td>Height of workpiece /mm</td><td>C</td><td>4</td><td>5</td><td>15 30</td><td>90</td></tr></table></body></html>\n\nThe shortest curing time and longest curing time of commercial powder coatings were tested by acetone solution and BYK colorimeter. Residual analysis, main effect analysis, and general linear  \n\nfitting analysis were carried out on the shortest and longest curing time by Minitab, to analyze the influence of furnace temperature, heating rate, and workpiece thickness on curing time. Table 2 shows the full factorial experimental design and experimental results generated by Minitab software.  \n\nTable 2. Experimental design and results of over-drying powder coatings   \n\n\n<html><body><table><tr><td>StdOrder</td><td>Run Order</td><td>A</td><td>B</td><td>C</td><td>Minimum constant temperature</td><td>Maximum constant temperature</td></tr><tr><td>3</td><td>1</td><td>180</td><td>8</td><td>30</td><td>curing time /min 16</td><td>curing time /min 180</td></tr><tr><td>29</td><td>2</td><td>220</td><td>15</td><td>5</td><td>5</td><td>35</td></tr><tr><td>10</td><td>3</td><td>180</td><td>20</td><td>15</td><td>13</td><td>130</td></tr><tr><td>20</td><td>4</td><td>200</td><td>15</td><td>90</td><td>30</td><td>250</td></tr><tr><td>16</td><td>5</td><td>200</td><td>8</td><td>90</td><td>35</td><td>260</td></tr><tr><td>31</td><td>6</td><td>220</td><td>15</td><td>30</td><td>12</td><td>110</td></tr><tr><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>......</td><td>·.....</td><td></td><td></td><td>.....</td><td>....</td><td>.....</td></tr><tr><td>25</td><td>30</td><td>220</td><td>8</td><td>5</td><td>4</td><td>30</td></tr><tr><td>24</td><td>31</td><td>200</td><td>20</td><td>90</td><td>25</td><td>245</td></tr><tr><td>23</td><td>32</td><td>200</td><td>20</td><td>30</td><td>18</td><td>50</td></tr><tr><td>12</td><td>33</td><td>180</td><td>20</td><td>90</td><td>50</td><td>390</td></tr><tr><td>27</td><td>34</td><td>220</td><td>8</td><td>30</td><td>13</td><td>105</td></tr><tr><td>17</td><td>35</td><td>200</td><td>15</td><td>5</td><td>8</td><td>70</td></tr><tr><td>36</td><td>36</td><td>220</td><td>20</td><td>90</td><td>19</td><td>185</td></tr></table></body></html>",
        "category": " Materials and methods"
    },
    {
        "id": 15,
        "chunk": "# 3. RESULTS AND DISCUSSION",
        "category": " Results and discussion"
    },
    {
        "id": 16,
        "chunk": "# 3.1 DSC curve analysis  \n\nFigure 1 shows the DSC curve of polyester thermosetting powder coating during curing at $20{}^{\\circ}\\mathrm{C}-300{}^{\\circ}\\mathrm{C}$ (the heating rate is $10\\ \\mathrm{^{\\circ}C}\\ /\\ \\mathrm{min})$ . There is an obvious endothermic transition at $62.7~^{\\circ}\\mathrm{C}$ , where the temperature is the melting point of the powder coating. When the temperature further increases, the curve begins to show an exothermic transition near $133~^{\\circ}\\mathrm{C}_{\\mathrm{\\i}}$ indicating that the powder begins to cure at this temperature; as the temperature continues to rise, it can be seen that the exothermic reaction rate gradually increases, and the maximum exothermic rate is between $180~^{\\circ}\\mathrm{C}$ and $220~^{\\circ}\\mathrm{C}$ , which is also the fastest curing temperature of powder coating. By analyzing the DSC curve of polyester thermosetting powder coatings, it can be concluded that the curing temperature range of powder coatings is $133^{\\circ}\\mathrm{C}\\sim230^{\\circ}\\mathrm{C}.$ , and the best curing temperature range is $180\\sim220^{\\circ}\\mathrm{C}$ .  \n\n![](images/9c3eebe32057fbd8c420d6a7eb5b6ae9fb0fecd35e2ae7dc5bd027c50a9801d8.jpg)  \nFigure 1. Non-isothermal DSC curve of polyester thermosetting powder",
        "category": " Results and discussion"
    },
    {
        "id": 17,
        "chunk": "# 3.2 DOE full factorial test data analysis  \n\nThe residual plot can be used to determine the stability and abnormality of the test data. In the DOE full-factor test, Minitab software is used to carry out residual analysis on the shortest curing time and the longest curing time. As shown in the residual diagram in Figure 2, the test data of curing time obey the normal distribution, the residual fluctuates randomly up and down the horizontal axis, and there are no obvious laws and trends such as rising and falling, indicating that the test data is stable and reliable, and no abnormal values are found, which can perform effective general linear fitting analysis and main effects analysis.  \n\n![](images/3d2eb42961d896152025f34f5c74dbb523615059dd225c860daafb5b21b62bd6.jpg)  \nFigure 2. Residual diagram of furnace temperature, heating rate, and workpiece thickness on constant temperature curing time.  \n\nTo explore the influence of each group of key parameters on the curing time, the main effect analysis was carried out on the test results. As shown in Figure 3, in the main effect diagram of each influencing factor, the slope and range of furnace temperature and workpiece thickness to the shortest curing time and longest curing time are larger, on the contrary, the slope of heating rate to curing time is smaller and close to 0, that is, the furnace temperature and the thickness of the workpiece are the main factors affecting the curing of the powder coating, and the heating rate has the least effect on the curing time, which can be ignored.  \n\nGeneral linear model fitting is primarily used to determine whether the association between the dependent variable and each independent variable is statistically significant. Statistically, the P value is a significant level, representing the significant degree of association between the dependent and independent variables. When the $\\mathrm{\\bfP}$ value is less than 0.05, it indicates that there is a significant linear correlation between the data of the two groups of fitted independent variables and dependent variables. When the $\\mathrm{~\\bf~P~}$ value is greater than or equal to 0.05, it means that there is no significant linear relationship between the two groups of independent variables being fitted and the data of the dependent variable, that is, the independent variable has a low degree of influence on the dependent variable. R-sq, also known as the goodness of fit, is an important parameter to measure whether the linear fitting model obtained from the linear fitting analysis is good or not. It is the ratio of the sum of squares of regression to the sum of squares of total deviation. The closer the value is to $100\\%$ , the better the linear fitting model obtained.  \n\n![](images/207df74e02fec67d2307c0a018995c5df8a8c47a340e59e11749c291ac8681d0.jpg)  \nFigure 3. Main effect diagram of furnace temperature, heating rate, and workpiece thickness.  \n\nTo further determine the influence degree of each influence factor on the curing time of powder coating, a general linear fitting was carried out on the results of the DOE full-factor test. Among them, furnace temperature, heating rate, and workpiece thickness are independent variables, and the shortest curing time and the longest curing time are dependent variables. The results generated by Minitab software were shown in Table 3. It can be seen from the fitting results that the R-sq of the linear model is $99.24\\%$ and $99.86\\%$ respectively, indicating that the linear model is in good agreement with the test data and the fitting results are reliable. As results in the two groups, the $\\mathrm{~\\bf~P~}$ values of heating rate, furnace temperature \\* heating rate, and heating rate \\* workpiece thickness are more than 0.05, and the P values of furnace temperature, workpiece thickness, and furnace temperature \\* workpiece thickness are less than 0.05. It shows that there is a significant linear correlation between furnace temperature, workpiece thickness, and curing time, and there is no significant linear correlation between heating rate and curing time. Therefore, in the following research, the influence of heating rate on curing time is small, and there is no significant linear correlation, which can be ignored.  \n\nTable 3. General linear model analysis of minimum curing time and maximum curing time.   \n\n\n<html><body><table><tr><td rowspan=\"2\">Source</td><td colspan=\"2\">Minimum curing time</td><td colspan=\"2\">Maximum curing time</td></tr><tr><td>P-Value</td><td>R-sp</td><td>P-Value</td><td>R-sp</td></tr><tr><td>Furnace temperature /°C</td><td>0.000</td><td></td><td>0.000</td><td></td></tr><tr><td>Temperature rate /°C·min-l</td><td>0.002</td><td></td><td>0.023</td><td></td></tr><tr><td>Workpiece thickness /mm</td><td>0.000</td><td></td><td>0.000</td><td></td></tr><tr><td>Furnace temperature /°C*Temperature rate /C·min-1</td><td>0.488</td><td>99.24%</td><td>0.853</td><td>99.86%</td></tr><tr><td>Furnace temperature /°C* Workpiece thickness /mm</td><td>0.000</td><td></td><td>0.000</td><td></td></tr><tr><td>Workpiece thickness /mm Temperature rate /°C·min-1*</td><td>0.203</td><td></td><td>0.374</td><td></td></tr></table></body></html>  \n\nThrough the above residual analysis, main effect analysis, and general linear model analysis, it can be concluded that the most significant factors affecting the curing time of powder coating are furnace temperature and workpiece thickness, and the heating rate has little influence on curing time. Therefore, the influence of furnace temperature and workpiece thickness on the curing time of powder coating is mainly considered in the following studies. The following will take furnace temperatures of $220^{\\circ}\\mathrm{C}$ , $200^{\\circ}\\mathrm{C}$ , and $180^{\\circ}\\mathrm{C}$ as examples to explore the influence of different workpiece thicknesses on the curing time of powder coatings under fixed furnace temperatures, and design the curing process model of powder coatings.",
        "category": " Results and discussion"
    },
    {
        "id": 18,
        "chunk": "# 3.3 Design of curing process model for powder coatings  \n\nTo meet the production requirements, workpieces of different thicknesses need to be combined and enter the curing chamber at the same time. Therefore, a reasonable combined thickness difference of steel plate needs to be set to prevent the coating from not fully curing on the thick plate or over-drying on the thin plate due to the unreasonable setting of combined thickness difference. The basic principle of setting combined thickness difference is: the shortest curing time of a thick plate is less than the longest curing time of a thin plate. After obtaining the shortest and longest curing time of steel surfaces with different thicknesses, the curing process design model is drawn to guide the optimal design of drying time of steel plate combination with different thicknesses and reduce the drying energy consumption in the coating process.  \n\nUnder the condition of $220^{\\circ}\\mathrm{C}$ furnace temperature, the minimum curing time and maximum curing time of steel plate with characteristic thickness are measured and the curing process model diagram is designed based on the corresponding relationship between plate thickness and curing time. As shown in Figure 4 (a), the t1 curve is the shortest curing time curve of steel plates with different thicknesses, the $\\mathbf{t}_{2}$ curve is the longest curing time curve of steel plates with different thicknesses, the steel plate thickness $\\mathtt{h}_{0}$ can be combined with the thinnest steel plate thickness $\\mathbf{h}_{2}$ , and the energy consumption is the lowest, that is when the thick plate $\\mathtt{h}_{0}$ and the thin plate $\\mathbf{h}_{3}$ are cured at the same time, the thin plate will be over dried or the thick plate will not dry thoroughly, so it cannot be combined. Therefore, under the fixed furnace temperature, the maximum temperature $\\mathrm{T}_{1}$ is measured corresponding to the thinnest workpiece, the maximum temperature $\\mathrm{T}_{2}$ is measured corresponding to the thickest workpiece of the production line, the maximum curing time $\\mathbf{t}_{2}$ is measured corresponding to the powder coating under $\\mathrm{T}_{1}$ with BYK color difference instrument, and the minimum curing time $\\mathbf{t}_{1}$ is measured corresponding to the powder coating under $\\mathrm{T}_{2}$ with acetone wiping method. If $\\mathbf{t}_{1}<\\mathbf{t}_{2}$ , the two thicknesses can be combined for drying, if $\\mathbf{t}_{1}>\\mathbf{t}_{2}$ , the two thicknesses cannot be combined for drying. A comparative analysis of curing process models at $220^{\\circ}\\mathrm{C}$ , $200^{\\circ}\\mathrm{C}$ , and $180^{\\circ}\\mathrm{C}$ oven temperatures is carried out based on the designed curing process model. As shown in Figure 4(b), as the oven temperature decreases, the powder coating curing window moves to the right and widens, and the minimum curing time changes little with the furnace temperature slope, that is, the minimum curing time of powder coatings is mainly affected by its curing performance; the longest curing time changes with the furnace temperature and the slope changes greatly and the right shift is greater, that is, the longest curing time of powder coatings is greatly affected by the temperature of the oven and the thickness of the plate.  \n\n![](images/37a71b146e51de52af58eed0e443dbd4a94d7ba71f6ea76a9d792e25f8a29495.jpg)  \nFigure $4.220^{\\circ}\\mathrm{C}$ curing process model diagram (a) and $220^{\\circ}\\mathrm{C}$ , $200^{\\circ}\\mathrm{C}$ , $180^{\\circ}\\mathrm{C}$ process model comparison diagram (b).",
        "category": " Results and discussion"
    },
    {
        "id": 19,
        "chunk": "# 4. CONCLUSION  \n\nThe best curing temperature range of powder coating was tested by DSC, and the DOE all-factor test design was carried out within the best curing temperature range. Furnace temperature, heating rate, and workpiece thickness were set as independent variables, and the shortest curing time and longest curing time of powder coating were determined by the acetone wipe method and color difference method. Using Minitab software to carry out residual analysis, main effect analysis, and general linear fitting analysis on the determination results of curing time, it can be concluded that furnace temperature and workpiece thickness were the most influential factors on the curing time of powder coating, while heating rate had little influence on curing time. On this basis, the curing process model of powder coating is designed, which can effectively guide the selection of curing furnace temperature and curing beat of powder coating in the production line, and guide the selection of thickness difference during combined curing of workpieces with different thickness, to avoid problems such as over-drying of thin plate and impervious drying of thick plate, minimize energy consumption, improve production efficiency, and save cost.",
        "category": " Conclusions"
    },
    {
        "id": 20,
        "chunk": "# ACKNOWLEDGEMENT  \n\nThis paper is the periodical result of the Natural Science Foundation Project—Youth Fund Project (BK20180176 Construction and Mechanism of Corrosion Self-repairing Functional Coatings Based on Graphene-based Corrosion Inhibitors Nano-compartments).",
        "category": " References"
    },
    {
        "id": 21,
        "chunk": "# REFERENCES  \n\n[1] Wang, W. X., Wang Y.Y., Han Y.Y., Liu Z.L., and Wang C. X., Analysis of curing kinetics of polyester /TGIC powder coatings, Paint & Coatings Industry, 49, 41-46 (2019).   \n[2] Zhao, C.N., Liu, C.M., and Qi, X.A., Study on new powder Coating system for steel structural parts of construction Machinery, Paint & Coatings Industry, 51, 64-68 (2021).   \n[3] Mao, Y.D., Pan, G., Liu, Y. Q., W, T. Z., Qin, M. Y., Wang, X. R., and Wu J. S., Study on curing parameters of infrared curing powder coatings by gas catalytic combustion, Modern Paint & Finishing, 24, 11-14 (2021).   \n[4] Zhang, H., Yan, B. W., Yang, S., Huang, J.B., Liu, W. and Shao, Y. Y., Research status and development of functional powder coatings, Chemical Industry and Engineering, 37, 1-18 (2020).   \n[5] Ou, Y. J.Q., Chen, J. H. and Chen, W. G., Study on powder coatings for construction machinery, Coating and Protection, 2, 9-15 (2020).   \n[6] Gan, L., Sun, Z. J., Gu, Y. Z., Li, M. and Zhang, Z. G., Study on curing reaction of epoxy resin by temperature and isothermal non-model kinetics, Acta Polymeric Clinical, 8, 1016-1022(2010).   \n[7] Lin, Y. J. Test, and analysis of coating properties under different curing processes of powder spraying, World Nonferrous Metals, 3, 192-194(2018).   \n[8] Liu, H., Hu, C. L. and Liu, B. X., Analysis on Curing Process of Static Spraying Powder Coating on Aluminium Alloy Profile, Paint & Coatings Industry, 44, 64-67(2014).",
        "category": " References"
    }
]