【正文】 效實(shí)現(xiàn)大孔及復(fù)雜輪廓的加工。激光加工中的熱影響區(qū)相對(duì)較窄，其重鑄層只有幾微米?；诖耍す饧庸さ淖冃慰梢圆挥杩紤]。激光加工適用于任何可以很好地吸收激光輻射的材料，而傳統(tǒng)加工工藝必須針對(duì)不同硬度和耐磨性的材料選擇合適的刀具。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(wèn)題的最好選擇。激光切割的邊緣光滑且潔凈，無(wú)須進(jìn)一步處理。激光打孔可以加工用其他方法難以加工的高深徑比的孔。激光加工可以加工出高質(zhì)量的小盲孔、槽、表面微造型和表面印痕。激光技術(shù)正處于高速發(fā)展期，激光加工也如此。激光加工不會(huì)掛渣，沒(méi)有毛邊，可以精確控制幾何精度。隨著激光技術(shù)的快速發(fā)展，激光加工的質(zhì)量正在穩(wěn)步提高。超聲加工超聲加工為日益增長(zhǎng)的對(duì)脆性材料如單晶體、玻璃、多晶陶瓷材料的加工需求及不斷提高的工件復(fù)雜形狀和輪廓加工提供了解決手段。這種加工過(guò)程不產(chǎn)生熱量、無(wú)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(wú)應(yīng)力加工表面。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。在超聲加工中，實(shí)際切削由液體中的懸浮磨粒或者旋轉(zhuǎn)的電鍍金剛石工具來(lái)完成。超聲加工的變型有靜止（傳統(tǒng)）超聲加工和旋轉(zhuǎn)超聲加工。傳統(tǒng)的超聲加工是利用作為小振幅振動(dòng)的工具與工件之間不斷循環(huán)的含有磨粒的漿料的磨蝕作用去除材料的。成形工具本身并不磨蝕工件，是受激振動(dòng)的工具通過(guò)激勵(lì)漿料液流中的磨料不斷緩和而均勻地磨損工件，從而在工件表面留下與工具相對(duì)應(yīng)的精確形狀。音極工具振動(dòng)的均勻性使超聲加工只能完成小型零件的加工，特別是直徑小于100 mm 的零件。超聲加工系統(tǒng)包括音極組件、超聲發(fā)生器、磨料供給系統(tǒng)及操作人員的控制。音極是暴露在超聲波振動(dòng)中的一小塊金屬或工具，它將振動(dòng)能傳給某個(gè)元件，從而激勵(lì)漿料中的磨粒。音極/工具組件由換能器、變幅桿和音極組成。換能器將電脈沖轉(zhuǎn)換成垂直沖程，垂直沖程再傳給變幅桿進(jìn)行放大或壓抑。調(diào)節(jié)后的沖程再傳給音極/工具組件。此時(shí)，工具表面的振動(dòng)幅值為20～50μm。工具的振幅通常與所使用的磨粒直徑大致相等。磨料供給系統(tǒng)將由水和磨粒組成的漿料送至切削區(qū)，磨粒通常為碳化硅或碳化硼。另外，除了提供磨粒進(jìn)行切削外，漿料還可對(duì)音極進(jìn)行冷卻，并將切削區(qū)的磨粒和切屑帶走。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。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。 the workpiece is too flexible or slender。 the shape of the part is too plex。 without producing burrs or inducing residual machining can be defined as a process using mechanical(motion) machining utilizes other forms of energy。the three main forms of energy used in nontraditional machining processes are as follows: energy。 energy。 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 : chemical milling of pockets, contours, overall metal removal, chemical blanking for etching through thin sheets。photochemical machining(pcm)for etching by using of photosensitive resists in microelectronics。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