| 引用本文: | 邓凯,蔡颂,陶能如,熊显文,陈达,徐闻声,余凡.基于光斑重叠的激光表面标刻等效脉冲传热模型与工艺分析[J].中国表面工程,2024,37(3):204~219 |
| DENG Kai,CAI Song,TAO Nengru,XIONG Xianwen,CHEN Da,XU Wensheng,YU Fan.Equivalent Pulse Heat Transfer Model and Process Analysis for Laser Marking Based on Spot Overlapping[J].China Surface Engineering,2024,37(3):204~219 |
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| 摘要: |
| 目前激光表面标刻技术应用较为广泛，但标刻过程中涉及的能量耦合复杂。为满足激光标刻技术的发展需求，结合理论模型和试验分析对其能量耦合的原理进行探究。研究结果如下：重叠率在 91%~99%时，激光扫描速率 v 或激光脉冲频率 f 影响下的材料烧蚀深度会随重叠率的增加而增加，重叠率为 99%时，材料去除率达最大；在光斑直径 D 影响下的烧蚀深度随重叠率的增加而减少，重叠率为 91%时去除率最大。三种参数影响下，等效激光功率密度 I1=3.88 W / μm2时，将产生较大的反冲压力促进材料的去除，使激光标刻的能量利用率最大。面标刻中，线间距大于线段凹槽宽度时，导致线段叠加不能完全填充目标区域；线间距小于线段凹槽宽度时，会导致块体膨胀变形，表面质量被破坏；线间距与线段凹槽宽度接近时，目标区域可以被完全填充且表面质量不被破坏，标刻效果较好。通过分析空间上光斑重叠区域的能量耦合与时间上相邻脉冲的能量累积，整理得到等效脉冲传热数值模型，可对激光标刻的烧蚀深度进行更加简单有效的计算。 |
| 关键词: 激光标刻 高分子材料 等效脉冲 表面技术 |
| DOI：10.11933/j.issn.1007-9289.20230528001 |
| 分类号:TH161 |
| 基金项目:国家自然科学基金（51705141）；湖南省教育厅科学研究优秀青年项目（21B0523）；湖南省自然科学基金面上项目（2023JJ30183） |
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| Equivalent Pulse Heat Transfer Model and Process Analysis for Laser Marking Based on Spot Overlapping |
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DENG Kai1，2，CAI Song1，3，TAO Nengru1，XIONG Xianwen2，CHEN Da2，XU Wensheng4，YU Fan4
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1.School of Intelligent Manufacturing, Hunan First Normal University, Changsha 410205 , China ；2.School of Mechanical Engineering, Hunan University of Technology, Zhuzhou 412000 , China ；3.School of Mechanical Science & Engineering, Huazhong University of Science and Technology,Wuhan 430074 , China ；4.School of Meachanical Engineering, Wuhan Polytechnic University, Wuhan 430023 , China
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| Abstract: |
| Currently, laser surface marking technology is extensively utilized. Establishing a heat transfer numerical model for line marking to predict material ablation depth holds significant importance for advancing laser marking technology. The energy coupling in the marking process is intricately complex, primarily due to the multitude of pulses needed for pattern marking and the variance in spatial positions and timing of each pulse's irradiation. This complexity makes direct calculation of the heat conduction process during marking challenging. This paper presents an analysis of the combined effects of spot overlap and energy accumulation. It identifies that during the laser lens's movement along the processing path, numerous instances of similar spot overlap patterns occur. From this observation, two distinct methods for calculating spot overlap are derived. In real-world applications, the influence of the first spot overlap calculation method on the entire line marking process is minimal and can be disregarded, allowing the second method to be utilized for further calculations. Given that the time interval between the actions of any two adjacent pulses in space remains constant, the material's energy absorption attenuation can be precisely determined through the cumulative effect of pulse energy. Consequently, by averaging the total energy, the equivalent single pulse energy and equivalent pulse heat transfer numerical model for each spot area are derived. Laser surface marking experiments were conducted on acrylonitrile / butadiene / styrene copolymer plates (ABS plates), followed by ultrasonic cleaning to prepare the material surface for analysis. The processed surfaces were then evaluated using a surface roughness measuring instrument and a three-dimensional ultra-depth-of-field microscope. The effectiveness of the proposed equivalent pulse heat transfer numerical model for line marking was assessed by comparing the measured depths to the predicted values, taking into account the behavior of the ABS plates at various temperatures. Surface roughness was utilized as a metric to evaluate the quality of the marking. An in-depth analysis was performed to understand the discrepancies between the experimental and theoretical results, bridging theory with practical outcomes. The findings are as follows: the material's ablation depth increases with the overlap rate, ranging from 91% to 99%, due to the effects of laser scanning velocity v or laser pulse frequency f, with the highest material removal rate observed at a 99% overlap rate. Conversely, the ablation depth decreases as the overlap rate increases when considering the effect of spot diameter D, with the highest removal rate occurring at a 91% overlap rate. In scenarios influenced by three key parameters, an equivalent laser power density of I1=3.88W / μm2 generates significant recoil pressure, enhancing material removal and optimizing the energy efficiency of the laser marking process. In surface marking, the optimal coverage of the target area is crucial for achieving high-quality results. If the distance between lines exceeds the width of the line segment groove, then the overlapping of line segments fails to entirely cover the target area, leading to incomplete marking. Conversely, when the distance between lines is less than the width of the groove in the line segment, excessive material overlap can cause expansion and deformation, compromising the surface quality. However, setting the distance between lines to closely match the width of the groove ensures complete coverage of the target area without compromising surface quality, resulting in an effective marking outcome. This study further explores the dynamics of energy coupling in the spatial overlapping area of light spots and the accumulation of energy from adjacent pulses over time. By employing the concept of light spot diameter overlap, the overlap rate for each light spot area was estimated. Utilizing the principle of equivalent effect, an equivalent pulse heat transfer numerical model was developed, offering a more straightforward and efficient method for calculating the ablation depth of laser markings. |
| Key words: laser marking polymer materials equivalent pulse surface technology |
