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畢業(yè)設(shè)計（論文）外文資料翻譯
設(shè)計(論文)題目： 踏板組件（B）沖壓模具設(shè)計
學生姓名：
學 院： 機械與電氣工程學院
專 業(yè)： 材料成型及控制工程
班 級：
學 號：
指導教師：
外文出處：
年2月27日
1．外文資料翻譯譯文（約3000漢字）：
模具設(shè)計手冊
伊凡娜·蘇奇
14-8 表面清潔
制造的金屬零件可能含有潤滑劑、車間污垢和灰塵、磨料、材料碎片和大量其他雜質(zhì)或污染物的殘留物。通常，這些零件必須清潔，以便為某些其他精加工過程（如噴漆或其他涂層應用）準備表面。
選擇合適的清洗方法必須考慮到許多因素。首先，必須確定要清除的臟物或污染物的類型，因為清除油脂所需的表面清潔方法與清除金屬碎屑所需的方法不同。必須考慮成品零件的表面要求，要避免損害產(chǎn)品的某些特殊特性。例如，某些金屬板五金件的開口不應去毛刺，因為一側(cè)的粗糙度對其安裝很重要。
此外，在考慮到特定公司或工廠的清潔能力的情況下，必須針對后續(xù)的精加工過程對問題進行評估。
這有幾種零件清潔方法，每種方法使用不同的原理，每種方法適用于不同的清潔應用范圍。有些通過機械手段清除要去除的元素；另一些則使用化合物、蒸汽或電解質(zhì)、超聲波、鹽浴和其他變化來解決。下面列出了這些清洗過程的主要類別。
14-8-1機械清洗
機械清洗利用磨料和其他物體的機械作用，用于研磨、拋光、拋光、噴砂清理或噴丸處理等過程。磨料顆粒可以是干燥的，也可以是包含在液體中的，并應用于零件表面。機械清潔中使用的其他物體可以是任何東西，如碎布、玻璃珠或拋光劑。
這種清潔方法可用于清除污垢、鐵銹、飛邊、零件去毛刺或僅用于表面粗加工以進行后續(xù)精加工。實際操作程序取決于特定部分和預期結(jié)果。
振動清洗常用于小型金屬沖壓件，這些零件與以小石子或類似材料為形式的磨具混合，放置在振動或旋轉(zhuǎn)的大滾筒中。零件和研磨元件的同時移動能夠去除毛刺、平滑表面，并在一定程度上精加工邊緣和去除其銳度。較大尺寸的零件可以通過一個設(shè)備擦洗他們的表面，通過與砂帶接觸這種研磨方法來去毛刺和表面清潔。
噴砂清理使用磨料顆粒，將其推到要清理的零件上。它是一種用于黑色和有色金屬鍛件和鑄件或焊接件等的清洗方法。
噴丸與噴砂的不同之處在于，噴丸的清潔作用僅僅是對其提高材料疲勞強度的補充。這種類型的表面處理也能消除否則會產(chǎn)生應力腐蝕開裂的拉伸應力。在噴丸處理中，靠在零件上的物體不是由磨料引起的，它們通過產(chǎn)生大量的淺凹痕來攻擊表面，這使得該過程很容易與材料表面的冷加工相媲美。
所有的注重尺寸的零件都要用玻璃珠清潔表面。作為一種清潔方法，它優(yōu)于在液體中使用研磨泥漿。玻璃珠清潔可用于準備噴漆、釬焊、焊接和其他類似的制造工藝。它產(chǎn)生啞光飾面，因此也可用于裝飾目的。用玻璃珠清潔的一個決定性的優(yōu)點是，在清潔表面時，不會去除可測量的尺寸量。
14-8-2堿性清洗
最常用的工業(yè)清洗方法是堿性清洗，其作用基本上是物理和化學的，輔之以表面活性劑、乳化劑、分離劑、皂化劑和潤濕劑的組合，所有這些都會清洗部件。溶液可以通過攪拌來加熱。
可溶解的污垢顆粒被沖走。固體顆粒從零件中分離出來，允許在底部的污泥中沉淀，或通過過濾和類似程序從溶液中漂浮并去除。
堿性清洗可用于清除蠟類固體、金屬顆粒、油、油脂、灰塵和其他污染物。該工藝的應用是將零件浸泡在液體中或通過噴霧或乳化。這樣的清洗過程通常要經(jīng)過水洗和干燥循環(huán)。
14-8-3電解清洗
該工藝是一種特殊類型的浸沒清洗，工藝中包含電極。直流電通過溶液傳導，待清洗部分作為陽極，而電極作為陰極。有些工藝交替使用陰極-陽極名稱。在清洗周期中，氧氣在陽極處的凈化作用可能進一步有助于操作。
這種類型的清潔可用于除銹、準備磷化、鉻酸鹽處理、噴漆，特別是電鍍，后者要求更高的清潔度。
14-8-4乳化液清洗
這一過程使用兩種基本材料，它們彼此不溶，例如水和油，并結(jié)合一種能夠迫使它們?nèi)榛娜榛瘎?。這種類型的清洗用于嚴重污染的零件，通常在循環(huán)后進行堿性清洗，以最終去除非常微小的污染物。
乳化劑有兩種：（1）有助于在水中形成由溶劑組成的乳狀液，和（2）有助于在溶劑中形成由水組成的乳液的乳化劑。
常用的乳化劑有非離子聚醚、烴磺酸鹽、胺皂、胺鹽、甘油或多元醇。溶劑通常來源于石油，如環(huán)烷烴（煤油）。
14-8-5溶劑清洗
這種清洗方法包括將溶劑應用于有機污染物，如油或油脂，以試圖將它們從零件表面去除。有時，為了去除零件表面的溶劑，這種清洗必須進行堿洗。這種清洗也可用于去除電鍍零件上的水。
溶劑可以是石油基（如石腦油、礦油或煤油）或氯化烴（三氯甲烷、三氯乙烯、二氯甲烷）或醇（異丙醇、甲醇、乙醇）。其他溶劑包括但不限于苯、丙酮和甲苯。
清潔機制主要適用于有機污染物，如油脂或油。這些雜質(zhì)很容易溶解和去除，或從零件表面沖洗掉。
14-8-5-1蒸汽脫脂
溶劑蒸汽脫脂是溶劑清洗的一個專業(yè)分支。它使用氯化或氟化溶劑去除油脂、蠟或油等雜質(zhì)。將要脫脂的物體放在一個罐中，在這個罐中有一種溶劑是煮沸的。物體通過蒸汽的作用而脫脂，蒸汽比空氣重，從而使后者從油箱容積中排出。到達上部冷卻器區(qū)域后，這些加熱的蒸汽冷凝并滴回到加熱的地方。
14-8-6酸洗
酸洗使用含有有機酸、礦物酸和酸鹽的各種溶液，與潤濕劑和洗滌劑結(jié)合用于鋼鐵的清洗。這種C傾斜法可以用來除去油、油脂、氧化物和其他污染物，而不需要額外加熱。
酸浸洗和酸洗是非常相似的工藝，酸浸洗是更積極的處理，用于清除鍛件或鑄件和各種半成品的氧化皮。
無機酸和無機鹽很多，它們形成無機（礦物）酸溶液或酸鹽溶液或酸溶劑混合物。這些清洗液的有機成分可以是草酸、酒石酸、檸檬酸、乙酸和其他酸，以及酸鹽，例如硫酸鈉、氟化氫鹽或磷酸鈉。此過程中使用的溶劑可以是乙二醇或單丁基（和其他）醚。
14-8-7酸洗
金屬材料的酸洗去除了零件表面的氧化物或結(jié)垢。它也可用于去除其他污染物，方法是將零件浸入酸的液體溶液中。這種溶液的成分、溫度和成分的選擇可能不同，最常見的酸洗液是硫酸。在需要鍍鋅前蝕刻的地方使用鹽酸。不銹鋼的酸洗采用硝酸-氫氟酸。
酸洗的機理是氧化皮穿透裂紋，酸洗液與金屬發(fā)生化學反應。為了使酸洗液不腐蝕基底金屬，加入了以明膠、面粉、膠水、石油污泥等物質(zhì)形式存在的抑制劑。緩蝕劑可以減少鐵表面的損失，減少氫脆的范圍，同時保護金屬不受點蝕的影響，點蝕可能發(fā)生在酸洗過度的地方。
14-8-8 鹽浴除垢
鹽浴除垢工藝用于除垢，必須先進行酸洗或酸浸洗才能徹底除垢。鹽浴除鱗可分為三類：氧化型、還原型和電解法。該模式甚至可以與前兩個過程一起使用。
氧化型鹽浴除鱗是最常用的除垢方法，因為它的簡單性，即使電解法提供更大的除垢能力。還原法的優(yōu)點是鹽浴溫度較低。
去除的水垢與除鱗鹽一起，形成不溶性污泥，必須用機械方法去除。因此，這些雜質(zhì)可以沉淀在一個平底鍋中，然后放在那里收集。
14-8-9超聲波清洗
當超聲波能量應用于氯化烴溶劑溶液、水和表面活性劑或任何其他清潔溶液類型時，將促進清潔過程、清除各種污染物。它可用于在材料中去除薄顆粒，或清除復雜部件、貴金屬、或封閉單元，并用于清除需要極度清潔的地方。
超聲波工藝的缺點是成本高，這是因為設(shè)備的初始成本和維護成本要高得多。然而，這種類型的清潔被發(fā)現(xiàn)是有益的，因為以前只有手工清潔方法。
14-9表面涂層
選擇表面涂層時，應考慮其必須覆蓋的基本金屬。一些涂層被用作防止磨損、腐蝕、氧化以及許多其他原因的保護。表面涂層在基本金屬本身和環(huán)境之間形成屏障，有時對其穩(wěn)定性有害。有涂層可以改變摩擦性能，增強零件的美觀性。各種涂層可用于各種應用，但最常用于保護基本金屬（基本產(chǎn)品）免受外部影響。
即使是組件內(nèi)的兩個金屬部件也能夠通過形成電偶電池來相互影響，這如果選擇不當，基本材料可能對其涂層產(chǎn)生不利的反應。因此，在選擇涂層的保護類型和保護量時，必須考慮對形成電偶的可能性的評估。這涉及到涂層的性質(zhì)是朝其下面的金屬陰極還是陽極。
例如，即使鎳對鐵是陰極的，而鋅是陽極的，鋼也可以通過鎳或鋅涂層免受其他影響。鎳通過成功地阻止外部腐蝕環(huán)境對材料的影響來保護鋼，為此，這種涂層必須沒有氣孔。鋅比鋼更容易腐蝕，而腐蝕性反應的副產(chǎn)物，氧化鋅，相當大，損害腐蝕過程并保護涂層材料。
許多金屬能夠形成氧化膜，當其穩(wěn)定時，作為該特定材料的保護涂層。鋁氧化物在酸性環(huán)境中生長，在那里形成厚的保護層，但一旦堿性合金陽極氧化，涂層收縮，變薄，堅硬，穩(wěn)定。一些氧化劑，如錫、鋅、鈦和其他的氧化劑，可以通過額外的化學或電化學處理來穩(wěn)定，這將使它們成為基本金屬材料的保護層。
這種保護的成功取決于對原電池過程的正確分析，在此過程中，陽極溶解的金屬必須受到相等和相反的陰極反應的保護。
14-9-1電鍍
電鍍過程實際上應該被稱為電離，因為它利用電鍍零件和電鍍材料之間的電偶原理將材料顆粒轉(zhuǎn)移到零件表面。在這一過程中，直流電被施加到金屬鹽溶液中，在該溶液中沉積待涂覆的零件。這些部分通過連接到能源的負端，承擔起陰極或負極的作用。大型部件懸掛在連接電源負極的銅棒上，小部件（如墊圈或螺栓）放置在金屬絲籃中。涂層金屬本身充當陽極，并以板、棒或擠壓形狀添加到鍍液中。
當受電流影響時，陽極金屬材料緩慢電離，其粒子進入鍍液。這些離子向陰極極化部分移動，在陰極極化部分表面以金屬晶體的形式沉積。某些類型的金屬涂層工藝要求對涂層浴進行加熱，有時添加液體攪拌作用以提高薄膜的均勻性。
涂層的發(fā)展速度取決于電流強度和鍍液溫度。如果鍍液溫度更高或電流的安培數(shù)更大，則涂層過程變得更快。但是，如果強度過高或溶液溫度過高，涂層會變得粗糙和不充分。電流必須是低電壓的（通常幾伏就足夠了），但強度必須相當高，每平方英尺涂層表面的電流為0.1到2安培或更多。
有機化合物有時被添加到鍍液中，它們的微量在很大程度上改變了涂層的性能。它們的影響主要是朝向美觀的外觀，隨后對涂層表面進行平滑處理，使其具有光澤。這些嚴格意義上的光學增強被它們提供的防腐保護減弱所抵消。
幾乎所有的金屬都可以用現(xiàn)代方法和現(xiàn)代技術(shù)作為涂層進行電鍍。然而，對于一些人來說，這個過程是如此昂貴，以至于它仍然只是一個技術(shù)上的好奇心。
最常見的四種鍍鋅工藝是：
l酸性電偶涂層，其中金屬以陽離子形式存在于簡單的鹽溶液中，例如硫酸鹽、硫酸鹽、氟硼酸鹽或氯化物的溶液中。該工藝用于鎳、銅、鋅和錫涂層的應用。
l復雜的堿性氰化物浴，帶有陰離子形式的金屬顆粒，連接到溶液的氰化物部分。這種類型的鍍液用于銅、鎘、鋅、銀和金涂層的應用。
l復雜酸浴，其中陰極沉積通過中間階段實現(xiàn)，或作為陰極膜。鉻酸就是一個例子，它能形成單重鉻酸鹽離子。
l金屬的堿性浴，形成兩性氧化物，如錫酸鈉浴，含有錫酸鈉或錫酸鹽，用羥基離子來穩(wěn)定。
2．外文資料原文（與課題相關(guān)，至少1萬印刷符號以上）：
Handbook of Die Design
Ivana Suchy
14-8 SURFACE CLEANING
Metal parts, as manufactured, may contain residues of lubric ants, shop dirt and dust, abrasives, splinters of materials, and a host of other impurities or contaminants. Often these parts have to be cleaned in order to prepare the surface for some other finishing process, such as painting or other coating application.
The proper cleaning method of such parts must be well chosen, with many factors in mind. First, the type of soil or contaminant to be removed has to be identified, since a different method of surface cleaning is needed for removal of grease than for metal chips. The surface requirements of the finished part must be taken into account in order not to use a method which may become detrimental to some special feature of the product. As an example, openings for certain sheet-metal hardware should not be deburred, as the roughness of one side is important for its installation.
Further, the problem has to be assessed with regard to the subsequent finishing processes, while bearing in mind the cleaning capacities of the particular company or plant.
There are several methods of parts cleaning, each using a different principle and each being applicable to a different range of cleaning applications. Some attack the elements to be removed by mechanical means; others use chemical compounds or steam or electrolytes or ultrasound, salt baths, and other variations. Main categories of these cleaning processes are listed below.
14-8-1 Mechanical Cleaning
Mechanical cleaning utilizes a mechanical action of abrasives and other objects, which are used in processes such as those of grinding, polishing, buffing, blast cleaning, or shot peening. Abrasive particles may be either dry or as contained in a liquid and applied against the surface of the part. Other objects used in mechanical cleaning may be anything from rags up to glass beads or buffing compounds.
This type of cleaning method may be used for removal of dirt, rust, flash, for deburring of parts, or just for roughing of the surface for subsequent finishing. The actual procedure depends on the particular part and the expected outcome.
Vibration cleaning is frequently used for small metal- stamped parts, where these are mixed with abrasives in the form of small stones or similar materials and placed in large drums, which are either vibrating or rotating. The simultaneous movement of parts and abrasive elements is capable of remov ing burrs, smoothing the surface, and to some degree finishing the edges and removing their sharpness. Larger-sized parts are deburred and surface-cleaned by an abrasive method of running them through an equipment which scrubs their surface by contact with an abrasive belt.
Blast cleaning uses abrasive particles, propelling them against the part to be cleaned. It is a cleaning method used with ferrous and nonferrous forgings and castings or to clean weldments, and so on.
Shot peening differs from blast peening in that its cleaning action is merely an addition to its actual purpose of improving the fatigue strength of the material. This type of finishing is also capable of relieving tensile stresses that would otherwise produce stress-corrosion cracking. In shot peening, the objects propelled against the part are not of abrasive origin.They attack the surface by creating a multitude of shallow indents, which makes the process easily comparable to cold working of the material surface.
Cleaning of the surface with glass beads is used for parts of all sizes. As a cleaning method, it surpasses that using an abrasive slurry within a liquid. Glass bead cleaning may be utilized in preparation for painting, brazing, welding, and other similar manufacturing processes. It produces a matte finish, for which reason it may also be used for decorative purposes. A definitive advantage of cleaning with glass beads is that while the surface is being cleaned, no measurable amount is removed.
14-8-2 Alkaline Cleaning
The most often used industrial cleaning method is alkaline cleaning, the action of which is basically physical as well as chemical, aided by combinations of surfactants, emulsifiers, separating agents, saponifiers, and wetting agents all attacking the part to be cleaned. The solution may be heated or agitated in motion by stirring.
Dissolvable particles of dirt are washed away. Solid particles are separated from the part and allowed to either settle in the fom of sludge to the bottom or be floated away and removed from the solution by means of filtering and similar procedures.
Alkaline cleaning may be used for removal of wax-type solids, metallic particles, oil,grease, dust, and other contaminants. The application of the process is by immersion in liquid or by spraying or emulsification. Such a cleaning process is often followed by a water rinse and a drying cycle.
14-8-3 Electrolytic Cleaning
This process is a specialized type of immersion cleaning, with the inclusion of electrodes within the process. A direct current is conducted through the solution, where the part to be cleaned serves as the anode while the electrode acts as the cathode. Some processes alternate the cathode-anode designation. The cleansing action of oxygen, which develops at the anode during the cleaning cycle, may further aid the operation.
This type of cleaning may be used for removal of rust, in preparation for phosphating,chromating, painting, and especially for electroplating, the latter demanding a higher degree of cleanliness.
14-8-4 Emulsion Cleaning
This process uses two basic materials, insoluble within each other, such as water and oil, combined with an emulsifying agent capable of forcing them to emulsify. This type of cleaning is used with heavily soiled parts, and the cycle is usually followed by alkaline cleaning for final removal of very minute contaminants.
Emulsifiers are of two types: (1) emulsifiers that aid the formation of emulsion which consists of a solvent in water, and (2) emulsifiers that aid the formation of emulsion which consists of water in solvent.
Frequently used emulsifiers are nonionic polyethers, hydrocarbon sulfonates, amine soaps, amine salts, glycerols, or polyalcohols. Solvents usually are of petroleum origin,such as naphthenic hydrocarbons (kerosene).
14-8-5 Solvent Cleaning
This cleaning method consists of an application of solvents to the organic contaminants such as oils or grease, in an attempt to remove them from the surface of parts. Sometimes such cleaning has to be followed by an alkaline wash, in order to remove the solvent itself from the part surface. This type of cleaning may also be used for removal of water from electroplated parts.
Solvents may be either petroleum-based (such as naphtha, mineral spirits, or kerosene)or chlorinated hydrocarbons (trichloroethane, trichloroethylene, methylene chloride) or alcohols (isopropanol, methanol, ethanol). Other solvents include but are not restricted to benzol, acetone, and toluene.
The mechanism of cleaning is applicable mainly to contaminants of organic origin, such as grease or oils. These impurities may be easily solubilized and removed, or washed off the part s surface.
14-8-5-1 Vapor Degreasing. Vapor degreasing with solvents is a specialized branch of solvent cleaning. It uses chlorinated or fluorinated solvents for removal of soils such as grease, waxes, or oil. The objects to be degreased are placed within a tank, where a solvent
is boiled. Objects are degreased by the action of vapors, which—be ing heavier than air—displace the latter from the volume of the tank. On reaching the upper cooler zones, these heated vapors condense and drip back down where they are reheated.
14-8-6 Acid Cleaning
Acid cleaning uses various solution containing organic acids, mineral acids, and acid salts,combined with a wetting agent and detergent for cleaning of iron and steel. Such a C leaning method may be used to remove oil, grease, oxide, and other contaminants without additional application of heat.
Acid cleaning and acid pickling are quite similar processes, with acid pickling being much more aggressive treatment, used for removal of scale from forgings or castings and from various half- finished mill products.
Mineral acids and salts are numerous, forming either inorganic (mineral) acid solutions or solutions of acid salts or acid-solvent mixtures. Organic components of these cleaning solutions may be oxalic, tartaric, citric, acetic, and other acids, with acid salts such as sodium acid sulfate, bifluoride salts, or sodium phosphates. Solvents used in this process may be ethylene glycol or monobutyl (and other) ethers.
14-8-7 Pickling
Pickling of metal materials removes the oxides, or scale, off the surface of parts. It may be used for removal of other contaminants as well, by immersing the parts in a liquid solution of acid. Such a solution may vary in its composition, temperature, and selection of ingredients, the most common pickling bath being sulfuric acid. Hydrochloric acid is utilized where etching prior to galvanizing is needed. For pickling of stainless steel,nitric-hydrofluoric acid is used.
The mechanism of pickling is that of a penetration of the scale through the cracks and chemical reaction of the pickling solution with the metal underneath. In order for the pickling solution not to attack the base metal, inhibitors in the form of gelatin, flour, glue, petroleum sludge, and other substances are added. Inhibitors can minimize the loss of iron surface and reduce the range of hydrogen embrittlement while protecting the metal from pitting, which may occur where pickling becomes excessive.
14-8-8 Salt Bath Descaling
The salt bath descaling process is used for removal of scale and it must- for a complete removal—be followed by acid pickling or acid cleaning. Salt bath descaling may be divided into three groups: oxidizing type, reducing type, and an electrolytic method. Thelatter may be used even in conjunction with the previous two processes.
Oxidizing type of salt bath descaling is the most often used method of scale removal because of its simplicity, even though the electrolytic method offers greater scale-removing capabilities. The reducing method's advantage is lower temperatures of the salt bath.
The removed scale, along with the descaling salts, forms an insoluble sludge, which must be taken out mechanically. For that reason such impurities are allowed to settle into a pan placed there for their collection.
14-8-9 Ultrasonic Cleaning
Ultrasonic energy, when applied to the solution of chlorinated hydrocarbon solvents or to water and surfactants or to any other type of cleaning solution, will boost the cleaning process, removing various types of contaminants. It may be used for removal of fine particles embedded within the material, or for cleaning of complex parts, precious metals, or sealed units, and also for cleaning where extreme cleanliness is required.
The disadvantage of the ultrasonic process is its high cost, which is due to the much higher initial cost of the equipment and its maintenance. However, this type of cleaning has been found beneficial where previously only hand-cleaning methods worked.
14-9 SURFACE COATING
Surface coating should be chosen with regard to the application it has to serve, along with a consideration for the basic metal it has to cover. Some coatings are used as a protection against abrasion, corrosion, oxidation, and for a host of other reasons. Surface coating creates a barrier between the basic metal itself and the environment, sometimes detrimental to its stability. There are coatings to alter the frictional properties and to enhance the an aesthetic appeal of the part. V arious coatings may be used for various applications but are most often chosen to protect the basic metal, the basic product, from outer influences.
Even two metallic parts within an assembly are capable of attacking each other by forming a galvanic cell, the same way a basic material may react adversely to its coating if chosen improperly. Evaluation of the possibility of a galv anic couple formation must therefore be considered when choosing the type and amount of protection a coating should ofer.This involves a survey of whether the coating is in its nature cathodic or anodic toward the metal underneath it.
For example, a steel may be protected from other influences by nickel or zinc coating,even though nickel is cathodic to iron and zinc is anodic. Nickel protects the steel by successfully blocking the influence of the outer corrosive environment on the material, for the purpose of which, such coating must be free of pores. Zinc provides protection by corroding more readily than steel, and a by-product of the corrosive reaction, zinc oxide, being quite sizable, impairs the corrosive process and protects the coated material.
Many metals are capable of forming oxide films, which—when stabilized—act as a protective coating for that particular material. Aluminum oxides thrive in acidic atmospheres,where they form thick protective layers, but once the basic alloy is anodized, the coating shrinks, turning thin, hard, and stable. Some ox ides, such as those of tin, zinc, titanium, and others, could be stabilized by an additional chemical or electrochemical treatment, which will turn them into protective layers for the basic metal material.
The success of such protection depends on proper analysis of the galvanic-cell process,during which an anodically dissolvable metal must be protected by an equal and opposite cathodic reaction.
14-9-1 Electroplating
The electroplating process should actually be called galvanizing, since it uses the principle of a galvanic couple between the plated part and plating material to transfer particles of material to the surface of the part. In this process, a direct electric current is applied to a solution of metal salts in which the parts to be coated are deposited. These parts assume the role of the cathode, or negative pole, by being connected to the negative end of the source of energy. Large parts are left hanging off a copper bar attached to the negative pole of the source, and small items, such as washers or bolts, are placed in wire baskets. The coating metal itself acts as an anode, and it is added to the bath in the form of plates, bars, or extruded shapes.
When affected by the electric current, the anodic metal material slowly ionizes, its particles entering the solution of the bath. These lttle ions travel toward the cathodic-polarized part, on whose surface they become deposited in the form of metal crystals. Some types of metal-coating processes require coating baths to be heated and sometimes a liquidstirring action is added to enhance the uniformity of the film.
The speed of the development of coating depends on the intensity of electric current and temperature of the bath. With a warmer bath or with higher amperage of the current, the coating process becomes faster. However, with too high an in