汽车涂装颗粒的分析和控制

涂层表面颗粒的多少是评价涂膜质量优良与否的重要标准,既影响着涂装线的生产效率,也体现着涂装线的综合水平。结合某涂装生产线的实际情况,分析了前处理、电泳、打胶、喷胶、打磨、喷漆等环节产生颗粒的原因,并提出了相应的防控措施。     

导读

汽车涂装起到防腐蚀、保护和装饰的效果,涂装弊病影响汽车的防腐性能和外观,本期针对汽车涂装弊病原因分析及解决进行重点报道邓烈雄的"电泳漆膜缩孔案例分析"阐述了调查和分析产生电泳漆膜缩孔的原因及解决问题的整个过程田伟东的"车架涂膜阶梯纹缺陷的分析与工艺控制"分析了短车架电泳涂装线车架涂膜阶梯纹弊病的成因,结合涂装生产线的实际情况,从涂装工艺和设备方面详细阐述了车架涂膜阶梯纹缺陷的形成及工艺控制。陆岩的"车身面漆异色颗粒问题的     

浅析前处理电泳线液体滤袋使用选择

介绍了奇瑞某涂装线过滤设备配置,阐述了电泳颗粒缺陷的种类,介绍了涂装行业前处理电泳线液体过滤袋的材料材质、过滤精度、溶污能力及针对颗粒缺陷的改进方法。     

汽车车桥涂装工艺设备探讨

论述了汽车车桥涂装工艺设计的重要性及关键点,介绍了车桥阴极电泳涂装线的工艺设计、涂装设备、涂层质量等情况。     

汽车涂装缩孔缺陷分析及改善

通过对车身涂层缩孔缺陷的分析及研究，明确涂层缩孔缺陷主要分为电泳缩孔缺陷、色漆缩孔缺陷、清漆缩孔缺陷三大类。生产现场采取增加电泳槽液除油过滤袋、增加喷漆机器人手臂套袖更换频次、优化现场作业人员操作顺序和工艺参数等措施，有效消除了车身涂层缩孔缺陷，提升了车身涂装外观质量。     

热镀锌板在汽车涂装线上出现电泳麻点的原因分析

某热镀锌板在汽车涂装线上电泳后出现麻点.通过涂装线现场调查及缺陷样板微观形貌和成分分析,确定麻点产生的原因是涂装前处理异常,使得磷化结晶异常,甚至无法成膜,导致后续电泳存在不均匀沉积.调整涂装前处理工艺参数后问题得以解决.     

车架涂膜阶梯纹缺陷的分析与工艺控制

分析了短车架电泳涂装线车架涂膜阶梯纹弊病的成因,结合涂装生产线的实际情况,从涂装工艺和设备方面详细阐述了车架涂膜阶梯纹缺陷的形成及工艺控制。     

机载设备涂层外观质量浅析

对比了机载设备产品涂装和汽车涂装的特点,认为机载设备的涂装不同于汽车的涂装。分析了机载设备在用手工空气喷涂法获得涂层时,影响其涂层外观质量的因素,以及预防缺陷的相应措施。     

汽车涂装颗粒的分析和控制

颗粒是涂装天敌。涂装车间面涂车身颗粒的多少直接体现涂装线管理水平，也体现了整条线的综合运营水平。重点阐述涂装颗粒的产生原因和防控措施。     

浅谈白车身缺陷对涂层的影响与预防

涂装是驾驶室生产的特殊工序,涂装效果直接决定驾驶室的外观质量,在白车身涂装过程中,白车身机体在前道工序所形成的缺陷直接影响涂层质量,而很多缺陷在涂装过程中无法消除,造成涂层缺陷,浅谈了白车身缺陷对涂层的影响与预防。     

The effect of shear‐thickening on the stability of slot‐die coating

Slot‐die coating is an economical roll‐to‐roll processing technique with potential to revolutionize the fabrication of nano‐patterned thin films at high throughput. In this study, the impact of shear‐thickening of the coating fluid on the stability of slot‐die coating was investigated. For the coating fluid, a model system fumed silica nanoparticles dispersed in polypropylene glycol was chosen. These dispersions exhibit shear and extensional thickening characterized through steady shear and capillary break‐up measurements. The critical web velocity for the onset of coating defect for different flow rates was measured, while the type of coating defect was visualized using a high speed camera. For the shear thickening particle dispersions, the coating failed through the onset of a ribbing instability. The critical web velocity for the onset of coating defect was found to decrease with increasing particle concentration and increasing fluid viscosity. The minimum wet thickness was studied as a function of capillary number for the particle dispersions and compared with a series of Newtonian fluids with similar viscosities. In all cases, shear‐thickening behavior was found to stabilize coating by reducing the minimum wet coating thickness when compared against a Newtonian fluid with similar viscosity at the same capillary number. Conversely, the shear‐thinning fluids tested destabilized the coating by increasing the minimum wet thickness when compared against a Newtonian at the same capillary number. The impact of shear‐thickening on slot‐die coating was further studied by quantifying the evolution of the ribbing instability with increasing web speed and by conducting tests over a wide range of coating gaps. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4536–4547, 2016     

汽车涂装线磷化除渣系统的改造

针对汽车车身涂装生产线磷化除渣系统存在的问题(如液位缺陷、液位传感器失效、流量不匹配以及出渣量小等),对旧的磷化除渣系统进行了改造。介绍了整改方法:选用耐温、耐污、防腐的液位传感器,安装方式由底部水平安装改为顶部垂直安装;调整泵的运行方式,以便调整清水罐的流量;将磷化槽沉淀锥由2对增至6对,提高了磷化浓液的收集能力,从而提高出渣量,等等。改造后,除渣系统的除渣效果大大增强,系统运行的稳定性也同时得到了提升。     

超白压花玻璃减反射辊涂镀膜生产工艺浅析

SiO2减反射镀膜超白压花玻璃的工业化辊涂镀膜生产目前仍处于探索及改进阶段。本文从辊涂镀膜原理出发,结合减反射镀膜液体及膜层的物理和化学性质,对AR辊涂镀膜实际生产的工艺流程、质量控制、膜层评价进行简单分析,并尝试对镀膜玻璃成品中常见的质量缺陷的成因进行分类探讨。     

结构缺陷对涂料涂层防腐质量的影响

船舶和钢结构制造过程中的结构缺陷都会直接影响涂料涂层的质量,甚至导致涂料涂层的防腐性能失效。本文论述了结构缺陷的类别、形态、危害和如何消除结构缺陷的措施。以确保涂料涂层的防腐质量。     

车身斜条纹缺陷的成因分析与对策

介绍了微型车涂装生产线上电泳前车身局部斜条纹缺陷成因分析及解决对策,既消除了斜条纹缺陷,又延长了磷化倒槽周期,降低了生产成本。     

A new device for coating single particles under controlled conditions

A new device for coating a single levitated particle in a controllable environment is designed and tested. This enables fluidized bed processing to be simulated experimentally on a single-particle level. The device consists of a coating chamber, which contains a capillary tube for levitating the particle, a micro-dispenser for producing discrete drops of controlled size and velocity and a device for supplying gas with specified temperature and humidity. The coating chamber consists of two parts, a confined space where the particle is levitated and a droplet insertion cone where the coating solution is injected into the particle suspending gas flow. A capillary with a well-defined diameter connects the droplet insertion cone and the area where the particle is levitated. The device is equipped with a piezo-actuated flow-through micro-dispenser that has the ability to produce discrete droplets with high reproducibility in terms of droplet size and velocity. The gas required for the coating process is taken from a gas container where the water content is analysed and kept at a minimum. A liquid flow is then introduced into the gas flow at a well-defined flow rate, mixed and evaporated in a three-way mixing vault. The humidified gas flow is then split into two separate flows; a suspending gas flow and a protecting gas flow for the inside of the coating chamber. The device is equipped with a high-speed video camera for monitoring both droplet production and droplet impact. Temperatures and flow rates throughout the device are measured and logged. Preliminary results show the influence of solvent, gas quality and coating procedure on the quality of the coating.     

用石蜡-CO_2超临界流体快速膨胀在流化床中进行细颗粒包覆

对超临界流体快速膨胀技术在流化床中进行细颗粒的表面包覆进行了研究 ,以实现细颗粒中关键成分的有效控制释放 .实验研究了含有包覆剂———石蜡的超临界二氧化碳流体通过微细喷嘴快速膨胀到装有细颗粒的流化床中 ,膨胀射流中所产生的微核在细颗粒表面均匀沉积 ,形成细颗粒表面薄层包覆 .结果分析表明 ,超临界流体快速膨胀前的温度是包覆过程的关键参数 ,通过控制操作过程参数可以获得良好的包覆结果     

工程机械行业结构件涂装线的设计

对国内大型工程机械业主要企业的结构件涂装线进行了调查研究,结果发现,传统涂装线存在投资大、产能低、能耗大、安全性和可靠性低以及有涂装缺陷等问题。借鉴汽车涂装线的生产方式,采用二涂一烘工艺、通过式线体、地链输送方式和风幕密闭保温等措施设计出新的结构件涂装生产线。生产实践证明,新涂装线克服了传统涂装线存在的缺陷,具有投资少、能耗小、产能大、可以柔性化生产的特点。     

浮法玻璃高速拉引下在线镀膜质量技术改进

由于目前浮法在线阳光镀膜工艺及设备所存在的局限性,不能适应浮法玻璃在线高速拉引下的镀膜玻璃的生产。镀膜设备在镀膜过程中出现的问题,影响了镀膜玻璃产品质量,被迫缩短了镀膜玻璃的生产周期,影响了企业的经济效益。通过进一步研发,对原有镀膜工艺和镀膜设备进行技术改进和提升,提高了镀膜玻璃产品质量,延长了镀膜玻璃生产周期。