【正文】 孔距及測(cè)量孔的深度用，千分尺用于測(cè)量孔系之間的同軸度。②決定銑削用量：粗加工余量,查《切削用量簡(jiǎn)明手冊(cè)》=,取。l 精銑上端面①刀具和機(jī)床不變。④計(jì)算基本工時(shí)式中。②決定銑削用量：粗銑加工余量，查《切削用量簡(jiǎn)明手冊(cè)》=,取。查《切削用量簡(jiǎn)明手冊(cè)》表12選擇不重磨損硬質(zhì)合金套式面銑刀，刀片采用YG6。因此實(shí)際切削速度和每齒進(jìn)給量為：④計(jì)算基本工時(shí)式中， 。④計(jì)算基本工時(shí)式中，入切量及超切量查《切削用量簡(jiǎn)明手冊(cè)》表2..29得， 。④計(jì)算基本工時(shí)式中，入切量及超切量查《切削用量簡(jiǎn)明手冊(cè)》表2..29得， 。切削速度的修正系數(shù)為， 則 根據(jù)機(jī)床說(shuō)明書(shū)取。③計(jì)算切削速度：查《實(shí)用機(jī)械制造工藝設(shè)計(jì)手冊(cè)》[8]得當(dāng)時(shí)， 根據(jù)機(jī)床說(shuō)明書(shū)取。③計(jì)算切削速度：查《切削用量簡(jiǎn)明手冊(cè)》，切削速度的修正系數(shù)為，則根據(jù)機(jī)床說(shuō)明書(shū)取。查《機(jī)械制造工藝設(shè)計(jì)簡(jiǎn)冊(cè)》表3123取切削速度，取，取切削速度。②確定進(jìn)給速度及切削速度：選擇60度單刃鏜刀，材料為硬質(zhì)合金。（7）鏜深20的盲孔l 粗鏜孔至①選用刀具，確定背吃刀量：選擇60度單刃鏜刀，材料為硬質(zhì)合金根據(jù)加工工藝要求取背吃刀量。④確定切削用時(shí)= =。③確定主軸轉(zhuǎn)速n查機(jī)床說(shuō)明書(shū)取，切削速度。③確定主軸轉(zhuǎn)速n查機(jī)床說(shuō)明書(shū)取，切削速度。圖41 工序尺寸圖在加工剩余三個(gè)孔時(shí)，孔的直徑由刀具直接保證，而孔的位置和加工精度則由所涉及的夾具保證。 定位方案的確定工件定位時(shí)，影響加工要求的自由度必須限制；不影響加工要求的自由度，有時(shí)要限制，有時(shí)可不限制，視具體情況而定?？稍谙露嗣嬖O(shè)計(jì)一定位盤(pán)與閥體的下端面接觸以限制了工件沿y軸移動(dòng)、繞x軸轉(zhuǎn)動(dòng)以及繞z軸轉(zhuǎn)動(dòng)三個(gè)自由度；同時(shí)通過(guò)固定在定位盤(pán)上的兩個(gè)定位銷(xiāo)與閥體兩孔之間的過(guò)渡配合限制了工件繞y軸轉(zhuǎn)動(dòng)、沿z軸移動(dòng)以及沿x軸移動(dòng)，定位圖如圖41。選擇定位銷(xiāo)（與工件配合的圓柱銷(xiāo)），取定位孔直徑為圓柱銷(xiāo)的基本尺寸，則應(yīng)選擇g6的圓柱銷(xiāo)，查《機(jī)床夾具設(shè)計(jì)》[10]表41選擇寬度b=4mm的菱形銷(xiāo)。本工序要求保證的位置精度主要是孔與孔間的同軸度誤差，選擇30H7孔中心線作為工序基準(zhǔn)，根據(jù)基準(zhǔn)重合原則，定位基準(zhǔn)與工序尺寸重合，因此=0。l 因?yàn)榛鶞?zhǔn)不重合誤差=0，基準(zhǔn)位移誤差=（mm）。在加工工件時(shí)通過(guò)擰緊螺母使壓板夾壓在工件上端面，同時(shí)在采用螺旋壓板組合夾緊時(shí)，由于工件接觸表面存在高度誤差，壓板位置不可能一直保持水平，因此可在螺母端面和壓板之間加以墊圈，以防止壓板傾斜時(shí)，螺栓不至因受彎曲作用而損壞同時(shí)也可減少因夾緊變形而產(chǎn)生的夾緊誤差。圖45 夾緊裝置 夾緊力的計(jì)算由圖可知夾緊力的方向與刀具運(yùn)動(dòng)方向一致，即與切削力同向。計(jì)算夾緊力是一個(gè)很復(fù)雜的問(wèn)題，所以一般只能粗略的估算。查《機(jī)床夾具設(shè)計(jì)手冊(cè)》[12]得=，=，=，=，=，=，=。查《現(xiàn)代加床夾具設(shè)計(jì)》得，其中L=10mm,Q=80N，故螺紋夾緊力。在不考慮工件表面變形的情況下，夾緊引起的定位基準(zhǔn)位移即為工序基準(zhǔn)位移。因?yàn)?，故夾緊裝置可用。圖52 固定盤(pán)二維圖設(shè)計(jì)完固定盤(pán)后還需設(shè)計(jì)一定位盤(pán)，工件直接與定位盤(pán)接觸，根據(jù)零件尺寸可設(shè)計(jì)出定位盤(pán)定位盤(pán)與固定盤(pán)通過(guò)凸臺(tái)連接，通過(guò)3個(gè)M12T型螺栓擰緊，如圖53所示。最后取平衡塊厚度d=15mm平衡塊如圖55所示。裝配時(shí)工件底面直接與定位盤(pán)接觸，通過(guò)一面兩銷(xiāo)進(jìn)行完全定位并通過(guò)夾緊機(jī)構(gòu)進(jìn)行夾緊。2）定位盤(pán)的安裝 將定位盤(pán)通過(guò)凸臺(tái)直接套在固定盤(pán)上，然后利用3個(gè)M12螺母與固定盤(pán)擰緊。5）轉(zhuǎn)位分度 加工完成孔1后拔出分度定位器，松開(kāi)3個(gè)M12T型螺栓，定位盤(pán)、分度定位機(jī)構(gòu)及工件一起通過(guò)定位盤(pán)凸臺(tái)繞固定盤(pán)轉(zhuǎn)動(dòng)。6）再轉(zhuǎn)位分度 重復(fù)孔2的加工過(guò)程。在大學(xué)四年的學(xué)習(xí)里，我們初步掌握了機(jī)械專業(yè)的基礎(chǔ)理論和基本技能，并通過(guò)一些必要的實(shí)驗(yàn)和簡(jiǎn)單的課程設(shè)計(jì)獲得了初步的實(shí)踐經(jīng)驗(yàn)。我國(guó)從事閥門(mén)生產(chǎn)的企業(yè)很多，且多屬中小企業(yè)。根據(jù)《20132017年中國(guó)閥門(mén)制造行業(yè)供需狀況與對(duì)外貿(mào)易分析報(bào)告》數(shù)據(jù)顯示，截至2011年底，我國(guó)擁有規(guī)模以上閥門(mén)企業(yè)(年?duì)I收2000萬(wàn)元以上)1485家，%。致 謝歷時(shí)將近四個(gè)月的時(shí)間終于將這篇論文寫(xiě)完，在論文的寫(xiě)作過(guò)程中遇到了無(wú)數(shù)的困難和障礙，都在同學(xué)和老師的幫助下度過(guò)了。本文引用了數(shù)位學(xué)者的研究文獻(xiàn)，如果沒(méi)有各位學(xué)者的研究成果的幫助和啟發(fā)，我將很難完成本篇論文的寫(xiě)作。Robotics and CIMS, Vol. 1, No. 2, 1984, pp. 167172.附錄A 外文文獻(xiàn)及譯文Machining fixture locating and clamping position optimization using genetic algorithmsNecmettin KayakDepartment of Mechanical Engineering, Uludag University, Go ru , Bursa 16059, Turkey Received 8 July 2004。 Optimization1. IntroductionFixtures are used to locate and constrain a work piece during a machining operation, minimizing work piece and fixture tooling deflections due to clamping and cutting forces are critical to ensuring accuracy of the machining operation. Traditionally, machining fixtures are designed and manufactured through trialanderror, which prove to be both expensive and timeconsuming to the manufacturing process. To ensure a work piece is manufactured according to specified dimensions and tolerances, it must be appropriately located and clamped, making it imperative to develop tools that will eliminate costly and timeconsuming trialanderror designs. Proper work piece location and fixture design are crucial to product quality in terms of precision, accuracy and finish of the machined part. Theoretically, the 321 locating principle can satisfactorily locate all prismatic shaped work pieces. This method provides the maximum rigidity with the minimum number of fixture elements. To position a part from a kinematic point of view means constraining the six degrees of freedom of a free moving body (three translations and three rotations). Three supports are positioned below the part to establish the location of the work piece on its vertical axis. Locators are placed on two peripheral edges and intended to establish the location of the work piece on the x and y horizontal axes. Properly locating the work piece in the fixture is vital to the overall accuracy and repeatability of the manufacturing process. Locators should be positioned as far apart as possible and should be placed on machined surfaces wherever possible. Supports are usually placed to enpass the center of gravity of a work piece and positioned as far apart as possible to maintain its stability. The primary responsibility of a clamp in fixture is to secure the part against the locators and supports. Clamps should not be expected to resist the cutting forces generated in the machining operation. For a given number of fixture elements, the machining fixture synthesis problem is the finding optimal layout or positions of the fixture elements around the work piece. In this paper, a method for fixture layout optimization using genetic algorithms is presented. The optimization objective is to search for a 2D fixture layout that minimizes the maximum elastic deformation at different locations of the work piece. ANSYS program has been used for calculating the deflection of the part under clamping and cutting forces. Two case studies are given to illustrate the proposed approach.2. Review of related worksFixture design has received considerable attention in recent years. However, little attention has been focused on the optimum fixture layout design. Manassas and Decries[1]used FEA for calculating deflections using the minimization of the work piece deflection at selected points as the design criterion. The design problem was to determine the position of supports. Meyer and Liou[2] presented an approach that uses linear programming technique to synthesize fixtures for dynamic machining conditions. Solution for the minimum clamping forces and locator forces is given. Li and Melkote[3]used a nonlinear programming method to solve the layout optimization problem. The method minimizes work piece location errors due to localized elastic deformation of the work piece. Roy andLiao[4]developed a heuristic method to plan for the best supporting and clamping positions. Tao et al.[5]presented a geometrical reasoning methodology for determining the optimal clamping points and clamping sequence for arbitrarily shaped workpieces. Liao and Hu[6]presented a system for fixture configuration analysis based on a dynamic model