基于激光双测头的印铁涂层厚度检测系统设计

发布时间：2019-01-28 23:53

【摘要】：随着印铁行业的不断发展,在金属薄板印涂领域对涂层厚度的检测技术提出了越来越高的要求。目前企业常用的涂层厚度检测方法为烘干称重估算法,该方法测量精度不高、存在滞后性。此外,市场上也出现了一些涂层测厚仪,例如磁电式、涡流式、激光式等,这些测厚仪的优点是操作方便、价格便宜,缺点是多为手持式、接触式测量,且测点有限,无法实现金属薄板全平面的涂层厚度自动测量与均匀性评估。为实现金属薄板全平面的涂层厚度高精度、非接触式自动检测,基于激光双测头测厚技术,结合机械伺服系统,设计了印铁涂层厚度检测系统。论文的主要工作如下:1.提出了一种利用激光双测头实现金属薄板涂层厚度测量及均匀性评估的方法。激光双测头差分测量原理可减小金属薄板Z向位置变化和机械振动等因素对测量结果的影响,结合机械伺服系统,通过激光双测头的扫描测量,实现全板涂层厚度的非接触式测量,并根据所测厚度数据评估涂层厚度的均匀性。2.设计了基于激光双测头的印铁涂层厚度检测系统。包括机械装置和测控系统的软硬件。机械装置主要由机架、X向金属薄板传送机构、Y向扫描测厚机构组成,介绍了各部分的组成和设计思路。测控系统硬件包括激光双测头、步进电机等的选型和接线,软件主要功能有膜厚测量、数据处理和三维拟合等。3.针对涂层厚度均匀性评估,提出一种膜厚评估算法。采用最小二乘原理与三次样条插值运算相结合,实现离散膜厚数据的三维拟合,并运用灰色理论对系统测量不确定度进行估计,解决了有限测点数据评估全板厚度均匀性准确度不高的问题。4.对系统进行了精度分析与实验测试。分析了激光双测头的线性度、重复性、采集同步性等性能参数,对机械装置的传动机构精度、测厚平台平面度等影响因素进行了实验分析和改进。选择金属薄板印涂试件进行涂层厚度测量,并根据膜厚评估算法对结果进行均匀性评估。实验结果表明检测系统稳定可靠,涂层厚度测量结果的三维图形极差约为1.4μm,系统测量不确定度为1.6μm,满足企业需求。
[Abstract]:With the development of the printing iron industry, the testing technology of coating thickness is required more and more in the field of sheet metal printing and coating. At present, the coating thickness measurement method commonly used in enterprises is the weight estimation method, which has low precision and lag. In addition, there are also some coating thickness gauges on the market, such as magnetoelectric, eddy current, laser, etc. The advantages of these thickness gauges are easy to operate and cheap, but the disadvantages are mostly hand-held, contact-type measurement, and limited measuring points. It is impossible to realize automatic measurement and uniformity evaluation of coating thickness in all plane of metal sheet. In order to realize the high accuracy and non-contact automatic measurement of coating thickness in all plane of metal sheet, a thickness measuring system of Indian iron coating was designed based on laser double probe thickness measurement technology and mechanical servo system. The main work of this paper is as follows: 1. In this paper, a method of measuring the thickness and uniformity of thin metal coating by using laser double probe is presented. The principle of laser double probe differential measurement can reduce the influence of the change of Z direction position and mechanical vibration of metal sheet on the measurement results. Combined with the mechanical servo system, the scanning measurement of laser double probe is carried out. The non-contact measurement of the thickness of the whole plate coating is realized, and the uniformity of the coating thickness is evaluated according to the measured thickness data. 2. The thickness measuring system of Indian iron coating based on laser double probe is designed. Including mechanical devices and measurement and control system hardware and software. The mechanical device is mainly composed of frame, X-to metal plate transfer mechanism and Y-direction scanning measuring mechanism. The composition and design idea of each part are introduced. The hardware of the measurement and control system includes the type selection and wiring of laser double probe, step motor and so on. The main functions of the software are film thickness measurement, data processing and 3D fitting etc. An algorithm for evaluating the thickness uniformity of coatings is proposed. Using the least square principle and cubic spline interpolation, the 3-D fitting of the discrete film thickness data is realized, and the uncertainty of the system measurement is estimated by using the grey theory. It solves the problem that the accuracy of evaluating the thickness uniformity of the whole plate is not high. 4. The precision analysis and experimental test of the system are carried out. The linearity, repeatability and synchronism of the laser double probe are analyzed. The influence factors such as the accuracy of the transmission mechanism and the flatness of the measuring platform are analyzed and improved experimentally. The thickness of the coating was measured and the uniformity of the results was evaluated according to the film thickness evaluation algorithm. The experimental results show that the measurement system is stable and reliable. The 3D graphic range of coating thickness measurement results is about 1.4 渭 m, and the uncertainty of measurement is 1.6 渭 m, which meets the needs of enterprises.
【学位授予单位】：南通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG173

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