粉末喷涂与应用

nullnullIntroduction to Powder Coating 粉末涂料介绍nullMetal Pretreatment for use with Powder Coatings 金属前处理nullMetal Preparation 金属的处理Pretreatment is a process intended to prevent the corrosion of the painted metal. 前处理是一种提高耐腐蚀的工艺Fe2 + O2 + H2O = RUSTIron reacts with oxygen and water in the atmosphere creating a powdery brown mess, not very ornamental, and continuous until no solid metal remains. 铁在空气中会与氧气和水反应生成褐色的物质nullMetal Preparation 金属处理Several methods of corrosion prevention can be used 几种防腐蚀的方法 For Steel: 铁： Automotive applications 汽车业 Primer : Underseals : Layers of Paint. nullSeveral methods of corrosion prevention can be used 几种防腐蚀的方法 For Steel: 铁： Architectural Applications 建筑业 Galvanising : Anti Corrosive Primer * Galvanising – covering with a layer of zinc.Metal Preparation 金属处理nullMetal Preparation 金属处理nullMetal Preparation 金属处理Several methods of corrosion prevention can be used 几种防腐蚀的方法 For Aluminium: 铝： Aluminium oxidises to form a white corrosion product 铝被氧化后形成白色的物质 Architectural Applications 建筑业 Anodise : Acid PrimersnullMetal Preparation 金属处理Why Pretreatment ? 为什么要前处理？ Powder coatings are used to enhance the appearance of buildings, machines, furniture,appliances: 粉末涂料用于改善建筑，机械设备，家具，以及其它器具的 表 关于同志近三年现实表现材料材料类招标技术评分表图表与交易pdf视力表打印pdf用图表说话 pdf 面： Designers and architects are searching to give distinction in terms of colour and effects. 设计师和建筑师提供了包括颜色和效果在内的 标准 excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载 等级 The problem is that all paints are porous： 所有的涂料均不同程度的存在会渗水的小孔 nullMetal Preparation 金属处理Molecules of water and salt can penetrate through the paint film. When they reach the metal surface the effect is worse than if the metal is uncoated. The answer = Pretreatment 水和盐分子可以渗透漆膜，一旦它们与金属表面接触，产生的影响甚至比没有喷涂还要糟糕。 要解决这个问 题 快递公司问题件快递公司问题件货款处理关于圆的周长面积重点题型关于解方程组的题及答案关于南海问题 就需要前处理。nullMetal Preparation 金属处理Pretreatment: 前处理 The chemical conversion of the metal surface before applying the powder coating. The metal then resists corrosion and the conversion permanently improves the adhesion of the coating. 在使用粉末涂料以前用化学方法对金属表面进行处理，可以改善耐腐蚀性和增加涂层的附着力。 nullMetal Preparation 金属处理The performance of the powder coating is only going to be as good as the metal preparation. We will cover three types of metal treatment systems 粉末涂料的功能类似于金属处理，我们将介绍三种的金属处理方法 Iron Phosphate for Steel用于铁系的磷酸铁 Zinc Phosphate for Steel用于铁系的磷酸锌 Chromate for Aluminium用于铝的铬酸盐 Other systems can be used and information is available. 当然还有其它处理方法nullMetal Preparation – Iron Phosphate 金属处理 — 磷酸铁Metal pretreatment can be applied by spray or dipping. 金属前处理可以借助喷淋或浸渍In the case of iron phosphate the process could look like this: 下面是磷酸铁的工艺流程Stages 1, 2 and 3 can be either spray or dip 步骤1，2和3均可采用喷淋或浸渍D R A I ND R A I NStage 1 Clean & PhosphateStage 2 RinseStage 3 Rinse & SealWork FlownullMetal Preparation – Iron Phosphate 金属处理 — 磷酸铁Typical 3 Stage System 典型的3步骤流程 Metal Substrate Steel – Phosphatising System 金属基材 None Ferrous – Clean and Etch Stage time duration 1 – 90 seconds 不同步骤所需的时间 2 – 45 seconds 3 – 30 seconds Stage temperature 1，2和3步骤所需的温度 40 – 60oC Drying/干燥温度 100 – 120oC Typical concentration 2 – 3 % by volume 典型的浓度 Typical acidity典型的酸值 pH 3.5 – 5.5 Typical coating weight 典型的膜重 20 – 40 mg/ft.nullMetal Preparation – Zinc Phosphate 金属处理 – 磷酸锌Zinc Phosphate process for steel tends to be more complicated 磷酸锌的工艺流程复杂一些Stage 1 CleanStage 2 RinseStage 3 Phos- phateStage 4 RinseStage 5 RinseD R A I ND R A I ND R A I ND R A I NnullMetal Preparation 金属处理Dwell Time : Each stage depends on: 各阶段所需的时间，受下面的因素控制 The amount of pretreatment chemical dissolved in water 溶于水的前处理化学药品的浓度 The age of the chemical 化学药品的有效时间 Regular checking is required to give consistent good results – at least twice per shift. 通常要经常检查前处理的状态—一个班至少两次nullMetal Preparation – Zinc Phosphate 金属处理 – 磷酸锌Typical 5 Stage System 典型5步骤流程 Metal Substrate Steel – Phosphatising System 金属基材 None Ferrous – Clean and Etch Stage time duration 1 – 90 seconds 不同步骤所需的时间 2 – 45 seconds 3 – 60 seconds 4 – 30 seconds 5 – 30 seconds Stage temperature温度 40 – 60oC Drying干燥温度 100 – 120oC Typical concentration 典型浓度 2 – 4 % by volume Typical acidity 1 = alkaline 酸碱性 2 = acidic Typical coating weight 40 – 70 mg/ft. 典型的膜重nullMetal Pretreatment - BS 3189 Type 3Spray Phosphate Plant 9 stage pretreatment 九步法 Degrease脱脂 Rinse水洗 Rinse水洗 Rinse水洗 Acid Etch (phosphoric acid)表调 Zinc Phosphate磷酸锌磷化 Rinse水洗 Rinse水洗 De-ionised water去离子水水洗 Dry 干燥 Quality Standard BS6497 参考英国标准BS6497nullMetal Pretreatment – Quality Control 金属前处理 – 质量控制Titration Checks: 检测 工程第三方检测合同工程防雷检测合同植筋拉拔检测方案传感器技术课后答案检测机构通用要求培训 项目： 1. Cleaner 2. Rinses 3. Acid Concentration 4. Rinse 5. Phosphate Concentration and coating weight 7. Rinse 8. Observations Checked at regular intervals during normal production and before production commences 以上项目应在生产过程中定时和生产前进行检验nullMetal Pretreatment Dry 金属前处理 干燥To ensure metal surface is dry ready for powder coating. 在喷涂粉末涂料前必须保证金属工件已经完全干燥Drying oven - Phosphate PlantnullMetal Preparation – Chromate 金属处理—鉻酸盐For aluminium –chromate conversion 铝—铬酸盐处理British Standards exist for the conversion of aluminium – BS 6496 适用于铝的英国标准BS6496 The same conversion can be used for Galvanised steel--BS 6497 适用于电镀铁的英国标准BS6497Stage 1 CleanStage 2 RinseStage 3 EtchStage 4 RinseStage 5 Chrom- ateStage 6 – 7 RinseStage 8 Demin RinseD R A I ND R A I ND R A I ND R A I ND R A I ND R A I NnullMetal Preparation – Chromate 金属处理—鉻酸盐Typical 7 Stage System 七步法 Metal Substrate Aluminium / Aluminium Alloys 金属基材 Galvanised Steel – Clean and Etch Stage 1 Cleaning Stage 2 Rinse Stage 3 Deoxidise metal surface Stage 4 Rinse Stage 5 Chromate Stage 6 Rinse Stage 7 Acidulated Rinse Stage Temperature 80 – 100oC Drying 90 – 95oC Do not overheat at the dry off stage 干燥温度不能过高nullMetal Preparation – Chromate 金属处理—鉻酸盐Chromate conversion to Aluminium and Galvanised steel 鉻酸盐处理完铝和电镀铁后的变化Yellow Chromate Conversion Typical Coating 黄色鉻酸盐的变化 Weight (g/m2) Pale Yellow 0.2 – 0.7 Gold 0.7 – 1.6 Brown 1.6 – 3.5 Green mix chromate/phosphate 0.5 – 2.0 For Powder Coating a lightweight coating is recommended In the range 0.2 – 2.0 g/m2 应用于粉末涂料，膜重一般在0.2—2.0g/m2nullSpraying and Application of Powder Coatings 粉末涂料的喷涂与应用nullnullnullPowder Application Systems 粉末涂料的应用系统nullPowder Application Systems Feed Systems 粉末涂料应用系统 供粉系统Direct feed system from Drum to Gun. 粉末涂料直接从粉桶送至喷枪 The system shown feeds 1 gun 右图是只供一个喷枪的直接供粉系统nullPowder Application Systems Feed Systems 粉末涂料应用系统 供粉系统 Direct feed system directly from a 25 kilo box. This system is set up to feed 2 guns. Used mainly in manual operations. 右图为直接从粉末涂料的包装箱至喷枪的供粉系统。图中的设备适用于两把喷枪，通常用于人工喷涂。nullPowder Application Systems Feed Systems 粉末涂料应用系统 供粉系统 Bulk feed system, powder is supplied in a fibre bag. Weight of powder – up to 1,000 kilos per bag. Used mainly on automatic plants where colour change is limited. 大型供粉系统，粉末涂料一般1吨一个包装，用于自动喷涂系统，限于换色较少的场合。nullPowder Fluidisation Systems 粉末涂料流化系统Dry air passes through a membrane giving the powder liquid qualities. 干燥的空气通过微孔板，使粉末涂料象水一样流动。The air must be dry and free from water and oil. 空气必须除水和油nullPowder Delivery Systems 粉末涂料的传送系统nullPowder Delivery Systems 粉末涂料的传送系统 Actual powder feed system Venturi feed from fluid bed. 右图是用文氏管从流化床吸取粉末的送粉系统nullForces at work on the Powder Particles At any one time 4 forces are at work on the powder particle as it travels from the gun to the earthed work-piece. 粉末在离开喷枪到达工件时受4种力的影响 Air Resistance Electrostatic Attraction Weight (Gravity) Aerodynamic Force nullPowder Charging SystemsThere are 2 major categories in charging of powder coating corona and tribo: 粉末涂料主要有两种带电方法—静电/摩擦 Gun Type Charge Location充电位置 Internal External Remote Powder Supply X X Corona 静电法 Integrated Gun Powder Supply X X Tribo 摩擦带电法 XnullCorona Charging Systems 静电带电系统In this method, a high voltage generator is used to charge an electrode at the tip which creates an electrostatic field (or corona) between the gun and the work-piece. 利用高压电极使粉末带电，并在喷枪与工件间形成电场External Charging System/外充电系统nullCorona Charging Systems 静电带电系统Corona charging - manual system/手动枪 - automatic system/自动枪nullCorona Charging Systems 静电带电系统Internal Charging System 内充电系统nullCorona Nozzle Systems 静电枪的喷嘴The type of product to Be coated will influence The nozzle to be used on the Spray gun, two types are shownnullCorona Nozzle Systems 静电枪的喷嘴 Conical Spray Nozzles – used to give an evenly distributed film thickness over flat panels. 圆锥型的喷嘴一般用于喷涂平面，并得到膜厚均匀的涂层。 Interpon AF particle managed powder being applied on domestic appliances. 右图为Interpon AF粉末涂料用于家用设备nullCorona Charging Systems 静电带电法 The high voltage power supply charges the electrode 高压发生器使喷枪电极带电 The concentrated charge creates an electrostatic field 带上电荷后形成静电场 The electrostatic field causes the air to ionize and generate a corona 静电场使空气电离形成电晕 The corona emits electrons 电晕放射出电子 The electrons are picked up by oxygen molecules forming negative ions 这些电子借助氧分子形成负离子 nullCorona Charging Systems – cont. 静电带电法 The ions follow the field lines 负离子沿着电力线移动 The powder particles distort the field around them 粉末涂料粒子使周围的电力线产生扭曲 The distorted field lines direct ions to the powder particles 扭曲后的电力线引导离子被粉末涂料粒子吸附 The ions bombard the powder particles and transfer the electrons giving the particles a negative charge 吸附的离子轰击粉末粒子，并使其带上负电，形成负极 nullTribo Charging Systems 摩擦带电法Tribo electricity is generated by the friction of one material on another. In Tribo charged spray guns, the powder rubs on a specially formulated and shaped surface which allows charge to transfer. 摩擦带电是通过不同物质摩擦形成的，摩擦枪可以使粉末与特殊设计并有特殊结构的表面摩擦而带电nullTribo Charging Systems 摩擦带电法nullTribo Charging Systems 摩擦带电法Tribo nozzles in different configurations. 不同结构的摩擦枪喷嘴nullElectrostatic Fluid Bed Systems 静电流化床法nullPowder Penetration 粉末的吸附The picture shows the development of the corona (red dotted area). Articles passing through are charged with the negative ions (-). The charged powder particles are attracted to the earthed substrate. 右图显示了电场，电力线，粉末的充电及被接地的工件吸附过程。nullPowder Penetration 粉末的穿透Achieving penetration into deep recesses in most important when applying powder coating. 粉末涂料能否到达死角这对粉末涂 料的应用来说很重要The most effective controls are the nozzle pattern And air assistance. 有效的控制方法是选择合适外形的喷嘴及调整辅助空气It is possible to overcome the “Faraday Cage Effect” 现在，克服“法拉第”效应已成为一种可能nullPowder Penetration 粉末的穿透Reducing the “Faraday Cage” Effect 减弱“法拉第”效应To reduce the effect it is necessary To assist in the creation of charged air Particles inside the recess. This should be彻 achieved by increasing the air stream. 可以借助加大传送空气的压力来减弱“法拉第”效应nullFaraday Cage Effect “法拉第”效应 A Faraday cage can technically be defined as an area within which there is no electrostatic field. In finishing, this term is applied more loosely, and generally refers to an area such as inside corners or cavities that are difficult to coat. The reason why these areas are difficult to coat is that the adjacent surfaces to the inside of the corner attract the electrostatic filed, therefore deflecting the powder from penetrating into the recessed areas. At the same time , this recessed area is difficult for the aerodynamic forces to penetrate into without blowing powder off already coated areas. 法拉第区域可以被认为是静电屏蔽区。实际应用中定义更宽松，通常是指死角和洞等难喷涂区域。难喷涂的原因是这些区域的外围吸引了电荷，这样粉末就不能被吸附。 另外，从空气动力学来将，输送空气将粉末吹至这些区域也很难。nullBack Ionisation 反弹效应A = powder attracted to the earthed component B = build up to correct film thickness C = ionised air within the powder film repels oncoming particles A = 粉末吸附在接地工件 B = 形成合适的膜厚 C = 在涂层上的离子云抵制吸附带有同类电荷的粉末nullPowder Recovery Integrated System 粉末回收系统 Integrated Spray / Recovery Booth System 完整的喷涂/回收系统nullPowder Recovery Systems 粉末回收系统Typical cartridge back- Pulse cleaning design. Used in cartridge Recovery systems. 典型脉冲自清理设计， 通常适用于桶状回收系统nullPowder Recovery Systems 粉末回收系统Cyclone Recovery SystemThe cyclone is used to separate the powder particles from the air. The air is driven round the sides of the cyclone, reducing in velocity and releasing the powder to be collected at the base. Fine powder is usually transported out of the cyclone on the air flow. 旋风分离器根据粒径分离粉末，空气沿着旋风分离器壁做圆周运动，速度渐渐降低，并释放被收集的粉末至底部。细粉通常会随流动空气离开旋风分离器。nullPowder Recovery Systems 粉末回收系统Fine powder is collected on a filter system in the “after filters”. The pneumatic air pulse ensures air flow is consistent and the fine powder collected for disposal. 细粉通过滤芯滤层被收集。有力的气体脉冲保证了空气流动的连续性及需被分离的细粉收集。 nullPowder Recovery Systems 粉末回收系统A motor generates the air flow. Ensuring the correct air volume and velocity is maintained. 电机提供流动空气， 并保证气体流量和速 度。nullPowder in-line Sieving Systems 粉末过筛系统Rotary In-Line Sieve 旋转筛nullPowder Vibrating Sieving Systems 震动筛Vibrating sieves are designed to work either: - Free standing - In-line 震动筛适用于： - 独立区域 - 流水线nullPowder Reciprocator Cycle 粉末喷涂的往复机构Cycle Rate 往复速度 = No. Of Guns x Pitch of Guns x 60 喷枪数量x喷枪位置x60Conveyor Speed (mm/min) 传送链速度（毫米/分钟）This will ensure striations do not occur on the components being coated. 在喷涂中要保证不要形成带状涂层。nullApplication Practical 实际应用nullStoving and Curing of Powder Coatings 固化炉 及粉末涂料的固化nullTypes of Oven 固化炉的类型 Convection – energy is transmitted by air circulation to heat the components 对流 – 热量通过空气流动传送，加热工件 Radiation – energy is transmitted directly onto the parts without heating air between the parts and the radiation source 辐射 – 热量直接从辐射源被传送至工件而无需空气作媒体 Induction – energy is transmitted through inducing electrical eddy currents that generate heat in the metal parts 感应 – 热量借助电流来传送来加热金属工件nullThe Baking Process 固化过程The baking stage, during which the powder coating melts, flows, gels and finally chemically reacts (cross-linking) and cures. It is critical to the performance of the coating that the temperature and time at temperature are maintained. Most baking ovens are designed to take the substrate through a pre-programmed time – temperature profile. 固化过程包括粉末的熔融，流平，凝胶最后发生化学反应形成涂层。固化温度极其所占时间是非常重要的，大多数固化炉借助预先设置固化时间（温度曲线）来设计。nullPowder Application Radiation Stoving 粉末的辐射固化Gas fires Infra-Red oven used for industrial components. 左图为用于固化工业用品的瓦斯红外炉I-R emitters inside the oven cure the powder film when in direct line, as radiation energy. 右图为通过炉内红外发生器（热源）固化粉末涂料I-R is often used to boost the curing in front of a conventional air circulating oven. 红外热常常被用于传统的利用空气循环的固化炉的前段nullPowder Application Induction Stoving 粉末的感应固化Pipes passing through an induction coil at between 12 - 15 ft/min. 管子通过感应圈（速度为12-15英尺/分钟）Induction is extremely effective when curing powder coating applied to wire. 感应固化非常适和用于金属线的粉末涂料的固化nullStoving Effects 固化程度nullProblem Solving 问题的解决nullTop 5 Problems with Application 使用中的五个主要问题Differences in gloss between standard and coated parts - Understoved – High gloss - Overstoved – Low in gloss 。 在标准与喷涂的工件之间光泽不一样 - 固化不完全– 光泽高 - 过度固化 – 光泽低 Differences in colour between parts - Film thickness differences - Us of 2 different products (from 2 suppliers) 喷涂的工件之间的颜色不同 - 膜厚不同 - 使用不同的涂料（从两个供应商） nullTop 5 Problems with Application 使用中的五个主要问题Poor Adhesion – Chipping - Understoved - Poor cleaning or pretreatment 附着力不好 – 碎片剥落 - 固化不完全 - 工件清理或前处理不好 Poor attraction to work piece - Bad earth - Gun HT not adjusted - Voltage not switched on 吸附不良 - 接地不好 - 喷枪设置不好 nullTop 5 Problems with Application 使用中的五个主要问题 Contamination in coating – Bits - Poor booth/gun cleaning - Contamination from plant – oil and grease from conveyor - Poor metal cleaning 。 污染 – 砂粒 - 喷房和喷枪清理不好 - 车间的污染 – 传送链上的油脂 - 工件清理不好 nullTop Problems after application 使用后的主要问题Corrosion on parts cutAfter powder coating 工件在喷涂粉末涂料后在切口处 腐蚀nullTop Problems after application 使用后的主要问题Dirt Retention Poor maintenance 耐污性差 维持性能不好nullTop Problems after application 使用后的主要问题Water-spot blistering 水泡 Poor pre-treatment 前处理不佳