外文资料翻译=超声波清洗=2000字符=外文翻译

外文资料翻译译文 超声波清洗 超声波清洗技术是在工业领域中广泛应用的一种新方法，采用这种技术可以去除工件表面的磨削、研磨、抛光后残留的碎屑，清除工件表面残留的油污，甚至可以除去油漆层。超声波清洗能够 大范围的应用于 工业零件，大的方面可以到波音 747 飞机的引擎维修，小的方面可以到手表的小零件制作，都有它的用武之地，就目前而言，它以广泛应用电子、精密机械、照明工程、光学、冶金、医疗仪器设备等诸多领域。 超声波清洗技术在对工业方面的推动和影响是显而易见的，要想真正的理解超声波的价值，我们则需要 进一步了解它的原理。 超声波清洗原理 超声波清洗的作用，主要由一种 “ 空化效应 ” 的现象造成，它以每分钟数以十亿计的空泡向内爆裂，而后撞击到工件的表面，并将工件表面的附着物剥离，分散开来。对于那些手工清洗难以达到的位置，如深孔，死角等，超声波清洗也可以达到很好的清洗效果，这也是超声波清洗的优点之一。 超声波清洗常用频率在 20 kHz 到 50 kHz，常用清洗温度在 50 -80 。 超声波清洗系统中 ,空化效应是由一系列超声波换能器 将 声波导入清洗槽内的清洗液中而产生 ， 这个声波会 传遍整个清洗槽 , 并在液体中产生了波的压缩和扩张 。 在压缩波时 ， 清洗液中的分子被紧密的压缩在一起 ； 在扩张波时 ， 分子将被快速的拉开 。 扩张的过程十分神奇 ， 以至于分子被裂开时 ， 形成了精微的气泡 ，而且 气泡里是局部真空的 。 当气泡周围的压力变大时 ， 周围的液体就涌过来 ， 对气泡施压并使之破裂 。 当这个现象发生时 ，也 就产生了液体的喷射 ，会 使温度高达 9032华氏度 (约为太阳的温度 )。这个极高的温度 ， 伴随着液体喷射的速度 ，就 产生了一个非常强烈的清洗作用 。 然而 ，因为气泡的扩张和爆裂周期是很短暂的 ，又有 伴随在气泡外的液体迅速吸收 热量 ， 因此在清洗的过程中不会出现清洗槽和清洗液的过热现象 。 影响清洗效果的因素 有 7 个主要影响清洗效果的原因 : 1.清洗时间 2.清洗液温度 3.清洗液的种类 4.工件的外形设计 5.超声波频率 6.超声功率密度 7.清洗装夹方式 清洗时间 清洗时间 是影响超声波清洗效果的一个主要因素，它取决于工件的污染程度以及对清洁度的要求， 常用的 的清洗时间是 2-10 分钟，只有少数工件能够在很短的时间 内 清洗干净。 实际操作中可能在精细清洗前需要一个预处理 的 过程 ，有 一些工件需要一道以上的超声波清洗工序， 有些 时候， 也 需要布置超声波清水漂洗槽去除（前道工序） 槽内 残留的清洗剂。 温度和清洗剂 温度和清洗剂 是两个紧密相关的因素。一般来说，在使用水作为清洗剂时，清洗剂的温度最好在 60 左右 ，一些 PH 较高的溶液则需要更高的清洗温度。研究化学药品的 PH 值是一个好的方面，但是深入的讨论化学知识并不是这篇文章所要涉及的主要内容。因此，下面所列举的都是一些水基超声波清洗液的主要组成成分。 A.水（硬水，软水，纯水，或者蒸馏水） B.酸，或者碱 C.表面活性剂 润湿剂 分散剂 乳化剂 皂化剂 D.可选成分 螯合剂 抗化剂 缓冲剂 消泡剂 应该注意的是，在使用 化学药剂时，必须充分考虑以上因素。一些为水射流清洗设计的化学药品，包括一些防锈剂，则不适合用于超声波清洗作业中。 工件的装夹设计 超声波清洗的一般程序是 ： 把工件装入工艺料框，然后再经过 3-4 个工序（如：超声波清洗，喷淋漂洗（可选），浸泡漂洗，干燥），在清洗料框时，有时超声波辐射会被工件遮挡住。所以，大多数超声波清洗设备都被设计为专门用途，在设计阶段，要重点考虑超声 波换能器的布置方式，可以采用底置或侧置。对于自动声波清洗设备，必须要准确的布置换能器以确保清洗效果的一致性。一些工件对超声波清洗以及所用到的其他工序需要采取不同的装夹方式。一些工件需要在清洗过程中旋转或者微动以保证清洗的顺利进行。 超声波输出频率 目前大多数工业清洗应用中采用较低的工作频率 40 kHz 作为基础频率 。例如 20-25 kHz , 常用于超声波空化腐蚀较少的金属，或者极大阻碍或吸收超声波传播的场合。 功率密度（每加仑的瓦数）（ 1 加仑 = 3.8 升 ） 一般来讲，小的工件需要较高的功率密度以达到所要求的清洗效果。大多数工业清洗设备需要的功率密度在 50-100 瓦 / 加仑。不过，容积超过 50 加仑 的水槽，通常只需要大约 20 瓦 / 每加仑的功率密度，因为超声波系统水箱的容积越大，一般需要的功率密度呈下降趋势。 工件的清洗载入方式 在清洗设备的设计阶段，必须要充分考虑工件清洗时的载入方式。一些较大的工件、内部比较难以清洗的工件（例如一些铸造件），清洗时的原则是 :只能载入重量是清洗液的一半的工件清洗，例如，在 5 加仑 的水中 ( 大约 40 磅 ) ，一次只能载入 20 磅 的工件清洗，在大多数实践中，分两次载入较少的工件清洗比一次载入较多的工件清洗效果要好得多。 在设计一个高品质的超声波清洗系统时，以上所述的相关因素需要综合考虑，忽视了某一项都可能使清洗系统造成不良的反应。 Ultrasonic Cleaning Ultrasonic cleaning is a good fit for a wide range of applications, from removing swarf and grinding and polishing residue to treating parts covered in oil, grease, or layers of paint. Ultrasonics can be used to clean miniature watch parts or to support the overhaul of jumbo jet engines. And from an industry perspective, the fields of electrotechnics, precision mechanics and light engineering, optics, metal processing, and medical equipment have proven particularly receptive to the ultrasonic concept. So the impact of ultrasonic cleaning is clearly recognizable. But to truly understand the value of ultrasonics, one must understand how ultrasonic cleaners really work. Ultrasonic Cleaning Explained The cleansing effect of ultrasound is the product of a phenomenon called cavitation. Billions of minute gas bubbles implode, causing shock waves that undermine dirt and blast it off a parts surface. One of the key advantages of this process is that it allows users to clean part surfaces that are completely inaccessible to a manual cleaning process. Ultrasound frequencies generally range between 20 kilohertz and 50 kilohertz, depending on application requirements. Ultrasonic cleaning is typically performed at temperatures between 122 F and 176 F . In an ultrasonic cleaning system, cavitation is produced by introducing sound waves into a cleaning liquid by means of a series of transducers mounted to a cleaning tank. The sound travels throughout the tank and creates waves of compression and expansion in the liquid. In the compression wave, the molecules of the cleaning liquid are compressed together tightly. Conversely, in the expansion wave, the molecules are pulled apart rapidly. The expansion is so dramatic that the molecules are ripped apart, creating microscopic bubbles. The bubbles contain a partial vacuum. As the pressure around the bubbles becomes greater, surrounding fluid rushes in and collapses the bubble. When this occurs, a jet of liquid is created, resulting in temperatures as high as 9,032 F (roughly the temperature of the surface of the sun). The extreme temperature, combined with the liquid jets velocity, provides a very intense cleaning action. However, because the bubble expansion and collapse cycle is so short, the liquid surrounding the bubble quickly absorbs the heat, preventing the tank and cleaning liquid from becoming overly hot during the cleaning process. Secrets to Ultrasonic Success There are seven major concerns related to successful ultrasonic cleaning: 1. Time 2. Temperature 3. Chemistry 4. Part Fixture Design 5. Ultrasonic Output Frequency 6. Watts Per Gallon 7. Loading TimeCleaning times can vary tremendously in an ultrasonic process, depending largely on how dirty the part is and how clean is clean. A normal trial period is two to 10 minutes, since very few parts are sufficiently clean in a shorter period of time. Precleaning may be required to remove gross contamination or to chemically prepare the parts for a final clean. Some applications require more than one ultrasonic treatment to complete the required cleaning. Ultrasonic rinsing may also be required in some cases to more thoroughly remove wash chemicals. Temperature & ChemistryTemperature and chemistry are closely related. Generally, ultrasonic cleaning in an aqueous solution is optimized at 140 F . Some high pH solutions require higher temperatures. The chemical pH is a good place to start; but a thorough examination of chemistry is beyond the scope of this article. In brief, the following should be considered the main components of aqueous ultrasonic cleaning chemistry: A. Water (hard, soft, DI, or distilled) B. pH C. Surfactants Wetting agents Dispersants Emulsifiers Saponifiers D. Optional Ingredients Sequestrants Inhibitors Buffering agents Defoamers The chemical formulation must consider all of the above characteristics. Some chemicals designed for spray cleaning or that include rust inhibitors are not suitable for ultrasonic cleaning. Part Fixture DesignThe procedure for ultrasonic cleaning is generally as follows: Put parts in basket and place basket through three or four process steps (i.e., ultrasonic wash, spray rinse (optional), immersion rinse, dry). Some parts loaded in baskets can mask or shadow from the radiated surface of the ultrasonic transducers. Most ultrasonic cleaning systems are designed for specific applications. Bottom-mounted transducers or side-mounted transducers are important considerations during the process design stage. Automated systems must specifically address the location of the transducers to ensure cleaning uniformity. Some parts require individual fixturing to separate the part for cleaning or subsequent processes. Some parts require slow rotating or vertical motion during the cleaning to ensure critical cleanliness. Ultrasonic Output FrequencyThe majority of the ultrasonic cleaning that is done in industrial applications today uses 40 kHz as a base frequency. Lower frequencies, such as 20-25 kHz, are used for large masses of metal where ultrasonic erosion is of little consequence. The large mass dampens or absorbs a great amount of the ultrasonic cleaning power. WattsPer GallonIn general, smaller parts require higher watts per gallon to achieve the desired level of cleanliness. Most industrial ultrasonic cleaning systems use watt density from 50 to 100 watts per gallon. However, tanks over 50 gallons usually require only about 20 watts per gallon because ultras