【正文】 photochemical machining(pcm)for etching by using of photosensitive resists in microelectronics。Nontraditional Machining Processes IntroductionTraditional or conventional machining, such as turning, milling, and grinding etc., uses mechanical energy to shear metal against another substance to create holes or remove machining processes are defined as a group of processes that remove excess material by various techniques involving mechanical, thermal, electrical or chemical energy or binations of these energies but do not use a sharp cutting tool as it is used in traditional manufacturing hard and brittle materials are difficult to be machined by traditional machining traditional methods to machine such materials means increased demand for time and energy and therefore increases in costs。音極是暴露在超聲波振動中的一小塊金屬或工具，它將振動能傳給某個元件，從而激勵漿料中的磨粒。這種加工過程不產(chǎn)生熱量、無化學(xué)反應(yīng)，加工出的零件在微結(jié)構(gòu)、化學(xué)和物理特性方面都不發(fā)生變化，可以獲得無應(yīng)力加工表面。采用傳統(tǒng)加工方法，非常難以加工硬脆材料如陶瓷等，而激光加工是解決此類問題的最好選擇。激光打孔深度可以控制到每個激光脈沖不超過一微米，且可以根據(jù)加工要求很靈活地留下非常淺的永久性標(biāo)記。激光束加工LASER是英文Light Amplification by Stimulated Emission of Radiation 各單詞頭一個字母所組成的縮寫詞。為了獲得電化學(xué)過程形狀復(fù)制的高精度和高的材料去除率，需要采用高的電流密度（范圍為10～100 A/cm2)和低電壓（范圍為8～30V）。利用陽極溶解，電化學(xué)加工可以去除具有導(dǎo)電性質(zhì)工件的材料，而無須機械能和熱能。由于蝕刻劑沿垂直和水平方向開始蝕除材料，鉆蝕（又稱為淘蝕）量進一步加大。電極之間的間隙只有千分之幾英寸，通過伺服機構(gòu)驅(qū)動和控制工具電極的進給使該值保持常量。傳統(tǒng)加工工藝依靠硬質(zhì)刀具或磨料去除較軟的材料，而特種加工工藝如電火花加工，則是利用電火花或熱能來電蝕除余料，以獲得所需的零件形狀。由于在加工過程中會產(chǎn)生殘余應(yīng)力，傳統(tǒng)加工方法還會造成刀具磨損，損壞產(chǎn)品質(zhì)量。第一篇：中英文翻譯注意事項中英文翻譯注意事項同學(xué)們：從目前發(fā)過來的中英文翻譯來看，大家需注意幾點：中英文翻譯，論文選擇時，一定要選質(zhì)量好的專業(yè)論文（一篇完整的論文應(yīng)包括摘要、關(guān)鍵詞、正文、參考文獻等；正文圖表，技術(shù)參數(shù)應(yīng)完整），否則大家發(fā)過來的論文翻譯還需要返工?；谝韵赂鞣N特殊理由，特種加工工藝或稱為先進制造工藝，可以應(yīng)用于采用傳統(tǒng)加工方法不可行，不令人滿意或者不經(jīng)濟的場合：； ； ；。因此，材料的硬度不再是電火花加工中的關(guān)鍵因素?；瘜W(xué)加工化學(xué)加工是眾所周知的特種加工工藝之一，它將工件浸入化學(xué)溶液通過腐蝕溶解作用將多余材料從工件上去除掉。在化學(xué)造型中最典型的公差范圍可保持在材料厚度的177。這個加工過程一般用于在高強度材料上加工復(fù)雜形腔和形狀，特別是在航空工業(yè)中如渦輪機葉片、噴氣發(fā)動機零件和噴嘴，以及在汽車業(yè)（發(fā)動機鑄件和齒輪）和醫(yī)療衛(wèi)生業(yè)中。通過將工具電極向去除工件表面材料的方向進給， mm范圍內(nèi)，～20 mm/min左右。雖然激光在某些場合可用來作為放大器，但它的主要用途是光激射振蕩器，或者是作為將電能轉(zhuǎn)換為具有高度準(zhǔn)直性光束的換能器。采用這種方法可以節(jié)省材料，這對于貴重材料或微加工中的精密結(jié)構(gòu)而言非常重要。激光切割的邊緣光滑且潔凈，無須進一步處理。因此，超聲加工被廣泛應(yīng)用于傳統(tǒng)加工難以切削的硬脆材料。音極/工具組件由換能器、變幅桿和音極組成。in some cases traditional machining may not be machining also results in tool wear and loss of quality in the product owing to induced residual stresses during machining processes, also called unconventional machining process or advanced manufacturing processes, are employed where traditional machining processes are not feasible, satisfactory or economical due to special reasons as outlined below: hard fragile materials difficult to clamp for traditional machining。chemical or electrochemical polishing where weak chemical reagents are used(sometimes with remote electric assist)for polishing or deburring and chemical jet machining where a single chemically active jet is schematic of chemical machining process is shown in the etchant attacks the material in both vertical and horizontal directions, undercuts may develop(as shown by the areas under the edges of the maskant in ).Typically, tolerances of 177。 types of nontraditional machining processes have been developed to meet extra required machining these processes are employed properly, they offer many advantages over traditional machining mon nontraditional machining processes are described in the following Discharge Machining(EDM)Electrical discharge machining(EDM)sometimes is colloquially referred to as spark machining, spark eroding, burning, die sinking or wire is one of the most widely used nontraditional machining main attraction of EDM over traditional machining processes such as metal cutting using different tools and grinding is that this technique utilizes thermoelectric process to erode undesired materials from the workpiece by a series of rapidly recurring discrete electrical sparks between workpiece and traditional machining processes rely on harder tool or abrasive material to remove softer material whereas nontraditional machining processes such as EDM uses electrical spark or thermal energy to erode unwanted material in order to create desired , the hardness of the material is no longer a dominating factor for EDM removes material by discharging an electrical current, normally stored in a capacitor bank, across a small gap between the tool(cathode)and the workpiece(anode)typically in the order of 50 volts/ shown in , at the beginning of EDM operation, a high voltage is applied across the narrow gap between the electrode and the high voltage induces an electric field in the insulating dielectric that is present in narrow gap between electrode and causes conducting particles suspended in the dielectric to concentrate at the points of strongest electrical the potential difference between the electrode and the workpiece is sufficiently high, the dielectric breaks down and a transient spark discharges through the dielectric fluid, removing small amount of material from the workpiece volume of the material removed per spark discharge is typically in the range of 105 to 106 gap is only a few thousandths of an inch, which is maintained at a constant value by the servomechanism that actuates and controls the tool Machining(CM)Chemical machining(CM)is a well known nontraditional machining process in which metal is removed from a workpiece by immersing it into a chemical process is the oldest of the nontraditional processes and has been used to produce pockets and contours and to remove materials from parts having a high strengthtoweight , the chemical machining method is widely used to produce microponents for various industrial applications such as microelectromechanical systems(MEMS)and semiconductor CM material is removed from selected areas of workpiece by immersing it in a chemical reagents or etchants, such as acids and alkaline is removed by microscopic electrochemical cell action which occurs in corrosion or chemical dissolution of a coatings called maskants protect areas from which the metal is not to be controlled chemical dissolution will simultaneously etch all exposed surfaces even though the penetration rates of the material removed may be only : chem