浅谈电泳二次流痕缺陷的控制

阴极电泳已广泛应用于汽车涂装,电泳二次流痕(俗称电泳水)是阴极电泳过程中的常见缺陷。结合车身调整、电泳滴水挡板设计、电泳吹气3种措施改善电泳二次流痕缺陷的实际案例,介绍控制电泳二次流痕缺陷的方法。     

关于钣金间隙对电泳流痕影响的研究

电泳流痕问题是车身涂装过程中的一大顽疾,严重的流痕不但会影响外观还会降低车身品质。造成电泳流痕的因素有多种,包括车身钣金结构(间隙)、电泳液特性、电泳后清洗工艺、UF液含漆量和烘烤温度等。以车身B柱过线孔部位为例,对钣金间隙对电泳流痕的影响进行了重点研究。     

浅析车身电泳流痕问题的解决

电泳流痕是涂装车间经常发生的质量问题,导致电泳流痕的主要原因是扣合缝隙中残留电泳液。通过分析车身扣合边结构、冲压模具设计与维护、焊接折边胶的挤胶位置变化以及电泳槽液固含量控制等,找出减少电泳流痕的最佳条件。     

车身电泳流痕产生原因分析与防治

电泳流痕是汽车涂装电泳过程中常见的质量问题，为了更加有效地解决此问题，本文对电泳流痕产生原因、解决方法进行了研究与总结。通过对汽车白车身设计、冲压工艺、焊装工艺、涂装工艺等方面的分析，找出了各个阶段与各工艺对电泳流痕产生的影响。可以从车身缝隙设计、冲压切口与毛刺控制、焊装包边间隙、焊装折边胶涂胶直径与距离、涂装电泳固体分、电泳后冲洗、电泳后沥水、电泳烘炉烘烤工艺设定、电泳后人工吹水、车身导流工装等方面入手，综合分析，提前预防从而控制电泳流痕的产生。     

浅谈电泳流痕综合治理

主要通过对涂装电泳流痕产生的原因分析研究,探讨了车身外板电泳流痕的综合解决方案。     

浅析电泳涂层二次流痕解决措施

分析电泳过程中二次流痕的产生原因，从车身结构、生产线布置、夹具安装高度等方面介绍解决电泳涂层二次流痕的措施。     

翼子板电泳流痕问题的解决方案

分析了电泳流痕的产生原因,通过验证讲述了电泳流痕问题的几种解决措施及各种措施的适用条件。     

一次后背门电泳流痕问题的解决

主要介绍了新车型开发过程中如何解决一次后背门电泳流痕问题的案例,采用5 Why及鱼骨刺图等质量工具对产生电泳流痕问题的影响因素进行了分析,最终通过调整折边胶的涂覆轨迹彻底解决了此批量电泳流痕问题,提升了整车防腐能力。     

驾驶室车门上铰链电泳流痕的解决

针对车门上铰链区域的电泳流痕问题,分析原因,通过优化生产过程和零件结构,采用增加吹水、取消空腔及增加导流槽的工艺方法,有效去除电泳液积存,解决了电泳流痕问题。     

新车型电泳流痕的分析与解决

为解决新车型在试生产期间的电泳流痕问题，以车身设计开发、涂装工艺和装焊工艺为切入点，通过调整电泳工艺和电泳烘干室参数，优化装焊胶和零件匹配尺寸，减少甚至消除了特定部位的电泳流痕，进而保证车身质量，提高涂装车间的生产节拍。     

浅谈汽车涂装电泳

简单介绍了汽车车身电泳涂装工艺流程,从实际生产过程当中寻求影响电泳涂装的工艺参数,以及电泳涂装的方法与技巧,在实际工作中分析解决了电泳过程中出现的问题,例如电泳流痕、缩孔等质量问题。     

电泳涂装常见缺陷及对策

针对汽车涂装前处理电泳生产线实际运行中出现的颗粒、缩孔、流痕等问题,分析了产生的原因,并提出了解决和预防对策。     

RHCM成型制品高光面形成微观机理研究

根据快速冷热成型技术(RHCM)成型塑料熔体在型腔内的填充流动规律,在普通注射成型机理研究基础上,从微观角度对RHCM技术在提高制品对模具的复原性,消除熔接痕、凹痕、银丝纹、流纹、表面浮纤等表观缺陷以及改善制品表面色差等方面的成型机理进行研究。结果表明,正是由于RHCM高温快速成型这一工艺特点,一方面确保熔体在型腔内的充分扩展与汇合,另一方面最大程度的限制制品的成型收缩,从而确保制件的最终成型品质。     

注塑制件熔接痕的形成、性能和预测

概述注塑制件熔接痕的形成及其危害，主要讨论塑料注塑制件中熔接痕的形成机理。熔接痕影响区的形成结构。影响熔接痕处性能的因素。以及工艺条件，模具几何条件对熔接痕处性能的影响等。在注塑模流动模拟的基础上。结合计算机图形学知识，利用计算机自动实现了注塑中熔接痕的自动识别。     

Investigation of wavelike flow marks in injection molding: A new hypothesis for the generation mechanism

The wavelike flow mark phenomenon is one of the surface defects that can occur during the injection stage of the injection molding process. The generating mechanism of this phenomenon is not yet well understood. In this paper, flow visualization data showing the way in which flow marks generate are reported for the first time. On the basis of these observations a new hypothesis for the mechanism causing flow marks is proposed. A mathematical expression is developed that expresses nondimensional flow mark curvature in terms of the processing conditions, the thermal properties of the polymer and the mold, and the interval of flow mark generation. This mathematical relationship is then tested over a wide range of operating conditions and for three different materials. Finally, the practical implications and significance of this new hypothesis are discussed.     

Investigation of wave-like flow marks in injection molding: Flow visualization and micro-geometry

The wave-like flow mark phenomenon is one of the surface defects that can occur during the injection stage of the injection molding process. The generating mechanism of this phenomenon is not yet well understood. In this paper the flow mark generation mechanims is investigated by (i) directly observing the behavior of the polymer in the flow front and contact line areas under molding conditions when flow marks are generated, and (ii) studying the micro-geometry of the flow marks after molding. Specific attention was given to (i) the point of origin of flow marks (relative to the moving contact line, as well as the history along the flow path), and (ii) the effect of thermal boundary conditions on the micro-geometry of flow marks. These findings and their significance in relation to the flow mark generation mechanism are discussed. It is proposed that the flow marks are caused by nonuniform thermal contraction in the solidifying layer immediately behind the contact line.     

注塑制品熔接痕的自动识别

通过对注塑模充模过程中熔接痕形成机理的数学分析，给出了一个结合流动模拟数值实现过程的熔接痕自动识别算法，结合计算机图形学知识，利用计算机自动实现了注塑成型中熔接痕的起始、发展和形成。该算法可预测复杂制件的熔接痕位置，并适用于气体辅助注射成型和反应注射成型。最后通过一个算例验证了该算法的实用性。     

浇口对注塑件流痕的影响

概述了注塑制品流痕的概念和成因。通过几次修改浇口类型和移动位置,证实了制品表面流痕缺陷是由于浇口类型和开设位置所致,调整时只要控制好这两个关键因素即可。     

Flow marks in injection molding of polypropylene and ethylene–propylene elastomer blends: Analysis of morphology and rheology

This paper reports an investigation of asynchronous flow marks on the surface of injection molded parts and short shots made from two different blends of polypropylene and ethylene–propylene random copolymer elastomers. Flow marks were observed on the surface with both blends; the spatial frequency of flow marks on the surface was greater in the blend B1, which also exhibited a greater contrast between the surface regions. The same blend was distinctly faster in the linear viscoelastic tests of shear creep recovery and shear viscosity growth. The degree of contrast between the flow‐mark regions and the out‐of‐flow‐mark regions was examined with a detailed analysis of SEM micrographs of the surface regions as well as the near wall regions from short shots. This revealed that the dispersed phase was highly stretched to cylindrical strands in the glossy surface regions of both blends and retracted in the dull regions to different extents in the two cases. A comparison of the particle size distributions and aspect ratio distributions in different regions established that rapid retraction of the suspended elastomer phase was the dominant cause of changes in particle shape between surface regions. Nonlinear shear creep and creep recovery curves of the two elastomer components showed that at a time of 1 s, the fractional strain recovery of the elastomer in B1 was much higher than that of the elastomer in B2. Hence, the nonlinear elastic recovery of the elastomer phase at short times is an important factor in flow mark formation with blends of polypropylene and olefinic elastomers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 423–434, 2005