智能制造技术在行业中的应用 第一讲 全智能喷涂线的控制

在喷涂生产线中,采用FX5U、3D质量检测和Python编程,可以快速调节喷枪工作频率、喷涂浓度和范围、喷枪到工件表面直线距离,使得产品复杂表面涂层的厚度均匀美观,成功打造智能制造的成功范例。     

喷涂机器人喷涂均匀性的规划

提出了一种针对喷涂均匀性的设计方案。介绍了喷涂机器人的喷头数学模型,并根据其数学模型确定了喷涂间距与喷枪到门距离的关系。对比了二次喷涂重叠与三次喷涂重叠的厚度差别,确立使用二次喷涂重叠。针对间距改变时的厚度变化情况,提出了一种后移喷枪使喷涂趋于均匀的轨迹规划方法。同时对喷涂过程中喷枪的参数作了分析与处理,使得物体表面较为简单的实现喷涂均匀。     

金属工件涂层在线检测系统的设计

通过对精锻部门现有的喷涂设备改良,结合喷涂工件特点和作业环境设计了一款基于西门子PLC的金属工件涂层在线检测系统。相对于传统的喷涂系统,该系统能够检测喷涂前涂料粘度和喷涂工件温度,并通过闭环控制系统将参数控制在最佳工作范围内,当达到喷涂条件后能自动进行喷涂,喷涂后可实时检测湿膜厚度,并能生成数据记录和报警日志等。存储的数据,有助于对喷涂工艺的分析。系统的应用减轻了劳动强度,提高了工作效率,提高了设备自动化控制程度。     

等离子喷涂涂层物理性能的超声检测

基于超声回波技术研究了等离子喷涂涂层的声学特性,采用浮力法获得了涂层的孔隙率.通过频率谱分析法对超声波在涂层中传播的理论进行了推导,建立了能够表征涂层特性的传递函数H(f),由传递函数获取了超声波在涂层中传播的速度、涂层界面的反射系数、密度、衰减系数等声学参量.经分析表明,涂层的声学参量能够反映涂层的质量.分别建立了涂层孔隙率与涂层界面的反射系数、声速、衰减系数的关系,结果表明,随着孔隙率的增加,衰减系数和反射系数增大,相反声速减小.     

利用电化学阻抗技术测试界面污染对涂层防护性能的影响

本工作采用交流阻抗技术与腐蚀电位监测,研究低碳钢基体表面污染面积(NaCl盐水污染)对醇酸清漆在0.5mol/LNaCl水溶液中防护性能的影响,并探讨有机涂层的失效机制。实验表明基体表面处理的好坏对有机涂层防护性能有着至关重要的影响。基体表面污染,不仅会削弱有机涂层的防护性能,而且能够加速涂层失效过程。     

微结构参数对多孔硅层热绝缘性能的影响

研究了多孔硅层厚度,孔隙率以及多孔硅中微晶粒尺寸三个微结构参数对其热绝缘性的影响机制.实验选用p ,p-两种掺杂浓度的硅片基底,采用电化学腐蚀法,通过改变腐蚀时间和腐蚀电流密度获得不同微结构参数的多孔硅层.分别采用显微拉曼光谱法及测量显微镜聚焦法测量了样品的热导率和厚度.研究发现,多孔硅层厚度影响热量传输路径,而孔隙率和微晶粒尺寸通过降低热导率从而使多孔硅的绝热性增强.     

钣金件轮廓线早期腐蚀和表面涂层早期剥落问题分析及解决方法

为了解决涂装钣金件轮廓线早期腐蚀和表面涂层早期剥落的问题,对某产品一批钣金外壳的生产全过程进行了跟踪,分析了毛刺去除工艺和涂装工艺对涂装质量的影响。分析结果表明,残留毛刺是轮廓线早期腐蚀的主要原因、氧化膜的存在是导致表面涂层早期剥落的根本原因。     

基于Boosting-KPLS的近红外绝缘涂层厚度检测

探索了一种基于近红外光谱法实现的硅钢表面绝缘涂层厚度检测方法。该方法采用声光可调滤波器近红外光谱仪采集硅钢表面绝缘涂层的近红外光谱,为进一步提取近红外光谱数据的有效信息,采用离散粒子群优化(discretebinary particle swarm optimization,DBPSO)算法对近红外光谱数据进行最佳波长变量筛选,并用筛选得到的新的光谱数据建立涂层厚度的Boosting-核偏最小二乘(kernel partial least squares,KPLS)定量分析模型。对比实验结果显示,Boosting-KPLS算法可以提高定量分析模型的分析准确度和速度,是一种较KPLS更为稳健、分析准确度更高的近红外光谱分析方法。文中所建定量分析模型对30个检验样本分析的绝对误差最小值为-0.02μm,最大值为0.19μm,最大相对误差为14.23%,完全符合实际检验的需要。     

管道超声导波检测用磁致伸缩涂层传感器研究

为克服磁致伸缩带材导波检测技术对耦合剂的依赖,又能满足对异形部件的检测需求,本文提出了一种磁致伸缩涂层导波检测的新方法。结合Fe-Ga磁致伸缩合金具有高的磁机械耦合系数,通过热喷涂技术制备Fe-Ga合金涂层,磁致伸缩为32 ppm。在1m长预置人工缺陷的316L不锈钢管道一端喷涂Fe-Ga涂层,设计磁致伸缩涂层传感器的结构和参数,得到产生偏置磁场与通入直流电的关系为17.05I Oe。通过频散曲线确定管道纵向导波的激励频率为180kHz,当偏置磁场为273 Oe时,得到缺陷处L(0, 1)、L(0, 2)和端面处L(0, 2)的回波信号幅值分别为0.24 V、0.20 V和1.44 V,说明磁致伸缩涂层传感器不仅能检测出缺陷,还能有效克服带材传感器需要耦合剂和适用对象有限的问题,可应用于管道在线监测,具有重要应用前景。     

含孔隙复合材料的力学性能分析

为研究孔隙率对复合材料力学性能的影响,基于细观力学方法,建立包含纤维、基体和孔隙三相的代表性体积单元（Representative Volume Element,RVE）.通过数值模拟得到不同孔隙率下复合材料的基本力学参数,并通过实验对比验证参数的有效性.将这些参数运用在复合材料层板的低速冲击模拟和压缩模拟中,研究孔隙率对复合材料层合板抗冲击性能和压缩强度的影响.     

Coating thickness optimization for a robotized thermal spray system

Thermal spraying techniques are used to protect or improve the surface performance of a workpiece by adding melted (or heated) powders onto the surface. Thickness and uniformity control are critical for obtaining an excellent thermal spraying coating. In the contemporary manufacturing industry, with the increasing demand for efficient and accurate processes, robot manipulators and handling systems have been developed to control the movement of the spray gun relative to the workpiece surface, where the robot manipulators and handling systems lead the spray gun to reciprocate along a predefined path. However, the research on optimizing the path for generating the desired coating thickness is very limited. In this paper, a parametric coating thickness prediction model is adapted from our previous research. Then, the Nelder-Mead method drives the model to find out the optimal kinematic parameters of a zigzag (meander) path for a uniform coating with the desired thickness. Based on the obtained kinematic parameters, the trajectory and program of a robot end effector (spray gun) are yielded. Finally, a prototype system with an intuitive user interface is developed to integrate these functions. From the input of a Gaussian coating growth model and a substrate, it can provide an optimal path directly. At the end of this work, one case was implemented by a homemade spray system and a robot system for verifying the effectiveness of the system.     

Post processing of microstructures by PDMS spray deposition

A method of depositing polydimethylsiloxane (PDMS) onto microfabricated surfaces by spray coating is presented. Low-viscosity PDMS combinations suitable for spraying are developed by mixing Dow Corning Sylgard 184 with 200 Fluid 20 cSt, and also by dilution with hexane. Spray coating is carried out on rotating substrates using blank Si wafers. Film quality is characterised with mechanical and optical profilometry and process parameters are optimised to yield micron-scale thickness with low surface roughness. High gas pressures and substrate motion improve the quality of sprayed films. The coating process is extended to microstructures formed by lithography and etching of silicon, and it is found that heating to accelerate cross-linking improves conformal coverage. The material can be used in many applications requiring spin coated or cast PDMS. Spray coated PDMS can be used as an adhesion layer and construction of microfluidic channels is demonstrated by plasma activated bonding. The coatings can also adsorb alkanethiols and micro contact printing is demonstrated using embossed, spray coated PDMS and using spray coated etched stamps.     

Thin film formation on non-planar surface with use of spray coating fabrication

This paper presents a three-dimensional microfabrication and integration technology for MEMS smart materials that utilizes a spray coating method. Spray coating is shown to be most effective for additional deposition on non-planar surfaces. PZT films were formed both on flat and uneven surfaces at a thickness of about 1 μm. Perovskite structures were formed with suitable heat treatment and ferroelectric P-E hysteresis loop was also obtained. This paper is the first report from our group and other researchers on the deposition of smart materials for MEMS using a spray coating method. Spray coating has been proposed as an effective three-dimensional coating method which can be used to deposit piezoelectrics, pyroelectrics, magnetics, etc. for sensors and actuators. The hydrophilic and hydrophobic properties between the substrate surface and ejected liquid are most essential process factors in the spray coating method for improving the film growth conditions.     

A frequency-domain approach to determining the path separation for spray coating

Many modern spray deposition processes, such as spray painting or coating, are automated by using a robot to move an applicator in a series of passes over the surface being sprayed. Determining the robot path that creates the required coat thickness over the surface can be considered as an optimization problem, which traditionally has been solved in the spatial domain. In this paper, results from sampling theory are used to transfer the problem into the spatial frequency domain, which determines the optimal separation between passes. The paper also shows how angled raster patterns can be combined to provide a continuous path over the surface that generates the required distribution of deposited material. Note to Practitioners-This paper is motivated by the problem of producing a given distribution of coat thickness during an automated spraying or deposition process. The coating is applied by an applicator that is moved by a robot whose path consists of a series of passes over a surface, and the aim is to determine the separation between the passes and the changes to the deposition rate or robot velocity that will produce the required thickness distribution. In many applications, a uniform thickness is required over the surface, but this paper also considers the problem of producing a shaped thickness profile. The analysis uses ideas from Shannon's sampling theorem to move the problem into the frequency domain, which provides a direct link between the Fourier transform of spray footprint on the surface and the separation of passes of the applicator as it moves over the surface. The paper also introduces a scanning strategy that consists of a combination of two sets of angled raster scans. Compared to paths consisting of conventional scans, this has the advantage that it reduces the time that the robot spends off the edge of the surface.     

A computer controlled spray system

A computer-controlled spray system is described that is used to control the application of thermal protection coatings to the Space Shuttle Exxternal Tank. The hardware and software requirements of the system as a manufacturing process are presented. The Spray Control System controls all turntables, elevators and spraying equipment used by the caoting process. Coatings are applied in a barber pole fashion, the turntable rotation, elevator vertical travel, and motions and functions of the spraying equipment being coordinated by the process control software.     

Fast, curvature-based prediction of rolling forces for porous media based on a series of detailed simulations

Using thermal spraying various surface coatings consisting of different material compositions can be manufactured. Besides different solid phases the resulting coating microstructure often contains a non-negligible amount of pores. In this context a roller burnishing process with a hydrostatic ball-point-tool is examined to compact the thermally sprayed coating, thereby reducing porosity. The rolling process is performed by a robot on free-formed workpieces. A simulation concept for the prediction of forces in a robot-guided roller burnishing process based on a series of detailed ABAQUS simulations is presented. It is shown that, based on these test configurations, the process forces can be calculated much faster and with sufficient precision. Thereby an optimal rolling path, which requires the least amount of normal force to be applied, can be determined efficiently leading to the decision whether a specific robot is equipped to handle the path. Furthermore, the described approach may be used as a pattern to apply similar methods to other engineering problems where accurate simulative solutions exist, but cannot be applied to problems of realistic size due to their expenditure of time.     

超疏水涂层表面黏附性能对海洋防腐和抑制海洋微生物附着行为的影响

目前关于超疏水涂层表面黏附性能对其腐蚀性能和表面细菌行为的影响不甚清楚。该文通过 调控聚脲醛纳米颗粒比例,采用喷涂法在 Q235 钢表面制备了具有不同黏附性能的超疏水涂层,并研 究了表面黏附性能对其防腐、抑菌行为的影响。电化学测试结果表明,滚动角＜10°的低黏附超疏水 涂层具有较大的电荷转移电阻和较低的腐蚀电流密度,其防腐能力显著优于滚动角为 175°的高黏附超 疏水涂层。结晶紫实验结果表明,与 Q235 基体相比,高黏附和低黏附超疏水涂层均能显著抑制铜绿 假单胞菌的附着,其中低黏附超疏水涂层抑菌率为 70.3%,表现出更为优异的抑制细菌附着性能。     

Process modeling,simulation, and paint thickness measurement for robotic spray painting

An algorithm and a computer program are developed for modeling of the spray painting process, simulation of robotic spray painting, and off‐line programming of industrial robots for painting of curved surfaces. The computer program enables the user to determine the painting strategies, parameters, and paths which will give the desired paint thickness. Surface models of the parts that are to be painted are obtained by using a computer‐assisted design (CAS) software. Models of relatively simple surfaces are formed by using the surface generation tools of the CAD software. For parts with more complex surfaces, point data related to the part is collected by using a laser scanner, and this data is used to form the CAD model of the part surface. The surface is then divided into small triangular elements and centroid coordinates, and unit normals of the elements are determined. Surface data together with the spray distance, painting velocity, and paint flow rate flux are used for simulation of the process and paint thickness analysis. Paint flow rate flux is determined experimentally by using different spray gun settings and painting parameters. During the experiments flat surfaces are painted by using a single painting stroke of the gun. Then, paint thickness measurements are made on the surfaces. It is observed that besides the technical specifications of the spray gun, air and paint nozzles, and paint needle, basic settings like paint tank pressure, spray air pressure, and gun needle‐valve position affect paint cone angle and paint flow rate, which finally characterize the spray painting process. For that reason, settings and parameters should be changed and the painting process should be simulated until an acceptable paint thickness distribution is obtained for the part that is going to be painted. The robot program is then generated in the robot's programming language. Paint thickness distribution on the painted surface is determined by measuring the thicknesses using the robot and the CAD model of the part surface. The thicknesses are measured at the centroids of the surface elements. A measurement probe of the coating thickness measurement gauge is attached to the wrist of the robot by using a feedback/safety adapter designed and manufactured for this purpose. © 2000 John Wiley & Sons, Inc.