外文翻譯物流管理論文-資料下載頁
2025-01-20 22:42本頁面
【導(dǎo)讀】在完成商業(yè)交易之后,物流將以最低成本和最高效益的方式執(zhí)行將商品從供應(yīng)商(賣方)流轉(zhuǎn)到顧客(買方)的過程。在物流過程中,既需要諸如物流設(shè)施和設(shè)備的硬件,也需要對(duì)物流實(shí)施信息化管理進(jìn)行物流標(biāo)準(zhǔn)化。此外,政府和物流組織的支持也不可或缺。在商品流轉(zhuǎn)過程中,往往會(huì)處于某種停滯的狀態(tài),物流的專業(yè)術(shù)語就稱之為儲(chǔ)存。這種因商品流轉(zhuǎn)過程中而產(chǎn)生的附加增值稱之為物流的場所價(jià)值。物流中經(jīng)常提到的“分割成更小的部分”就是配送加工中最為常見的形式。并能調(diào)整成適合鐵運(yùn)、汽運(yùn)和船運(yùn)的集裝箱標(biāo)準(zhǔn)規(guī)格尺寸。條形碼、銷售時(shí)點(diǎn)系統(tǒng)、電子數(shù)據(jù)傳輸系統(tǒng)、全球衛(wèi)星定位系統(tǒng)的使用,極大地提高了物流活動(dòng)的效率和精確程度。很多企業(yè)正通過出口、許可、合營或跨國經(jīng)營涉足國際市場。這種趨勢(shì)仍將持續(xù)。隨著這種趨勢(shì)的發(fā)展，開發(fā)國際物流網(wǎng)絡(luò)成為必須。整合物流管理和成本分析將更加復(fù)雜和困難。
【正文】 ne intricate shapes that would be impossible to produce with conventional cutting tools. This machining process is continually finding further applications in the metalcutting industry. It is being used extensively in the plastic industry to produce cavities of almost any shape in the steel molds. Electrical discharge machining is a controlled metal removal technique whereby an electric spark is used to cut (erode) the workpiece, which takes a shape opposite to that of the cutting tool or electrode. The cutting tool (electrode) is made from electrically conductive material, usually carbon. The electrode, made to the shape of the cavity required, and the workpiece are both submerged in a dielectric fluid, which is generally a light lubricating oil. This dielectric fluid should be a nonconductor (or poor conductor) of electricity. A servo mechanism maintains a gap of about to in. ( to mm) between the electrode and the work, preventing them from ing into contact with each other. A direct current of low voltage and high amperage is delivered to the electrode at the rate of approximately 20 000 hertz (Hz). These electrical energy impulses bee sparks which jump the dielectric fluid. Intense heat is created in the localized area of the park impact, the metal melts and a small particle of molten metal is expelled from the surface of the workpiece . The dielectric fluid, which is constantly being circulated, carries away the eroded particles of metal and also assists in dissipating the heat caused by the spark.In the last few years, major advances have been made with regard to the surface finishes that can be produced. With the low metal removal rates, surface finishes of 2 to 4 um. ( to ) are possible. With high metal removal rates finishes of 1 000uin. (25um) are produced.The type of finish required determines the number of amperes which can be used, the capacitance, frequency, and the voltage setting. For fast metal removal (roughing cuts), high amperage, low frequency, high capacitance, and minimum gap voltage are required. For slow metal removal (finish cut) and good surface finish, low amperage, high frequency, low capacitance, and the highest gap voltage are required.Electrical discharge machining has many advantages over conventional machining processes.1. Any material that is electrically conductive can be cut, regardless of its hardness. It is especially valuable for cemented carbides and the new supertough spaceage alloys that are extremely difficult to cut by conventional means.2. Work can be machined in a hardened state, thereby overing the deformation caused by the hardening process.3. Broken taps or drills can readily be removed from workpieces. 4. It does not create stresses in the work material since the tool (electrode) never es in contact with the work.5. The process is burrfree.6. Thin, fragile sections can be easily machined without deforming.7. Secondary finishing operations are generally eliminated for many types of work.8. The process is automatic in that the servomechanism advances the electrode into the work as the metal is removed.9. One person can operate several EDM machines at one time.
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