【導(dǎo)讀】本設(shè)計的內(nèi)容可分為機械加工工藝規(guī)程設(shè)計和機床專用夾具設(shè)計兩大部分。首先，通過分析B6065刨床推動架，了解到推動架在B6065刨床加工中的作用。運用機械制造技術(shù)及相關(guān)課程的一些知識，解決推動架在加工中的定位、加緊以及工藝路線的安排等方面的相關(guān)問題，確定相關(guān)的工藝尺寸及選擇合適的機床和刀具，保證零件的加工質(zhì)量。其次，依據(jù)推動架毛坯件和生產(chǎn)綱領(lǐng)的要求及各加工方案的比較，制定出切實可行的推動架加工工藝規(guī)程路線。最后，根據(jù)被加工零件的加工要求，參考機床夾具設(shè)計手冊及相關(guān)方面的書籍，運用夾具設(shè)計的基本原理和方法，擬定夾具設(shè)計的方案，設(shè)計出高效、省力、經(jīng)濟合理并且能保證加工質(zhì)量的夾具。在設(shè)計推動架機械加工工藝過程時要通過查表法準(zhǔn)確的確定各表面的總余量及余量公差，合理選擇機床加工設(shè)備以及相應(yīng)的加工刀具，進給量，切削速

　　

【正文】 復(fù)制其形狀，并留有必須的間隙。Electrical discharge machiningElectrical discharge machining has proved especially valuable in the machining of supertough, electrically conductive materials such as the new spaceage alloys. These metals would have been difficult to machine by conventional methods, but EDM has made it relatively simple to machine 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.10. Intricate shapes, impossible to produce by conventional means, are cut out of a solid with relative ease.11. Better dies and molds can be produced at lower costs.12. A die punch can be used as the electrode to reproduce its shape in the matching die plate, plete with the necessary clearance. 30