开合螺母下座体加工工艺及钻夹具设计【含CAD图纸】
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第3章 钻孔2-6.5夹具设计3.1研究原始质料利用本夹具主要用来钻孔2-6.5,因为加工精度不高,故在加工中,主要目的是降低生产成本,减轻劳动强度从而来提高效率。3.2定位基准的选择要合理选择定位基准,不然会影响加工过程的质量,进而最终工件质量。选择不合适的基准,故会增加加工过程或不合理工艺路线,导致夹具设计困难,最终达不到零件加工精度(特别位置精度)。所以我们应该根据零件的技术要求,以保证加工精度的要求,定位基准的合理选择。以已加工好的端面作定位夹具。由零件图可知:在钻孔前,平面进行了粗、精铣加工,孔钻、扩、铰加工。定位、夹紧方案:为了在定位误差范围满足要求,定位一面一 销一挡块,结构中的定位是简单易操作的。一边是底平面图的处理;在孔无位置公差要求,所以我们为定位基准设计的底面和两个孔钻的模式选择,以满足加工要求。底部和5自由度的两个定位孔限制工件的定位。3.3 切削力及夹紧力的计算钻孔选用:钻床Z525,刀具钻头。由文献可得:切削力公式: 式中 查表得: 其中: 即:实际所需夹紧力: 有:安全系数K可按:式中:安全系数 所以 通过计算实际夹紧力不大,夹具结构简单操作方便,采用螺旋夹紧机构。取,查文献移动螺旋夹紧时夹紧力计算:式中参数由文献查得: 螺旋夹紧力:由上述计算易得: 通过计算实际所需夹紧力不大,该夹具具有结构简单,操作方便,决定使用手动螺旋夹紧机构。3.4误差分析与计算该夹具以底面、中心孔定位基准,该孔1次性加工即可满足要求。由文献可得:销的定位误差 : 其中:, 夹紧误差 : 其中接触变形位移值: 查5表1215有。 磨损造成的加工误差:通常不超过 夹具相对刀具位置误差:取误差总和:从以上、所设计的夹具满足零件加工精度要求。3.5 零、部件的设计与选用3.5.1定位销选用本夹具用可换定位销定位表3.1可换定位销dHD公称允差121816150.01122514M124 3.5.3 钻套、衬套、钻模板设计与选用为了减少辅助时间采用可换钻套,以来满足达到孔的加工的要求。 图3.1 可换钻套铰工艺孔钻套结构参数如下表3.4 钻套dHD公称允差61212+0.018+0.007221810490.518衬套选用固定衬套其结构如图所示:图3.2 固定衬套其结构参数如下表3.5 固定衬套dHDC 公称允差公称允差12+0.034+0.0161218+0.023+0.0120.523.6 确定夹具体结构和总体结构对夹具体的设计的基本要求(1)应该保持精度和稳定性在夹具体表面重要的面,如安装接触位置,安装表面的刀块夹紧安装特定的,足够的精度,之间的位置精度稳定夹具体,夹具体应该采用铸造,时效处理,退火等处理方式。(2)应具有足够的强度和刚度保证在加工过程中不因夹紧力,切削力等外力变形和振动是不允许的,夹具应有足够的厚度,刚度可以适当加固。(3)结构的方法和使用应该不错夹较大的工件的外观,更复杂的结构,之间的相互位置精度与每个表面的要求高,所以应特别注意结构的过程中,应处理的工件,夹具,维修方便。再满足功能性要求(刚度和强度)前提下,应能减小体积减轻重量,结构应该简单。(4)应便于铁屑去除在加工过程中,该铁屑将继续在夹在积累,如果不及时清除,切削热的积累会破坏夹具定位精度,铁屑投掷可能绕组定位元件,也会破坏的定位精度,甚至发生事故。因此,在这个过程中的铁屑不多,可适当增加定位装置和夹紧表面之间的距离增加的铁屑空间:对切削过程中产生更多的,一般应在夹具体上面。(5)安装应牢固、可靠夹具安装在所有通过夹安装表面和相应的表面接触或实现的。当夹安装在重力的中心,夹具应尽可能低,支撑面积应足够大,以安装精度要高,以确保稳定和可靠的安装。夹具底部通常是中空的,识别特定的文件夹结构,然后绘制夹具布局。图中所示的夹具装配。加工过程中,夹具必承受大的夹紧力切削力,产生冲击和振动,夹具的形状,取决于夹具布局和夹具和连接,在因此夹具必须有足够的强度和刚度。在加工过程中的切屑形成的有一部分会落在夹具,积累太多会影响工件的定位与夹紧可靠,所以夹具设计,必须考虑结构应便于铁屑。此外,夹点技术,经济的具体结构和操作、安装方便等特点,在设计中还应考虑。在加工过程中的切屑形成的有一部分会落在夹具,切割积累太多会影响工件的定位与夹紧可靠,所以夹具设计,必须考虑结构应便排出铁屑。3.7夹具设计及操作的简要说明本夹具用于在钻床上加工端面孔。在底部平面工件的定位基准,中心孔,实现完全定位在定位环。手动螺旋夹持工件。夹紧机构,操作简单,夹紧可靠。如前所述,夹具设计,为了提高生产率,首先想到的是如何安装,拆卸方便,本程序是铰链板。钻模的表面,所以主要的钻削力,因为钻削力向下,铰链板压得我们使用,减少压力,钻削力和夹紧力的方向是相同的,它是更容易保证工件的稳定性,我们采用定位销和固定销定位,当我们把工件旋转,工件,使工件固定在固定脚的位置,然后用铰链板,将钻模板,可去除工件。大学课程设计(论文)题 目对合螺母座工艺及钻夹具设计所属系部所属专业机械设计与制造所属班级学 号学生姓名指导教师起讫日期目 录绪论31.1 设计任务31.2 任务分析31.3 与论文有关的部分背景资料调研31.3.1 开合螺母下座体的用途31.3.2 工艺流程31.3.3 夹具4第2章 工艺部分52.1 引言52.2开合螺母下座体的结构分析52.3工艺分析52.4制定工艺规程62.4.2 基准面的选择62.4.3 工艺路线的制定62.4.4 加工方法的选择62.4.5加工的顺序安排72.4.7 制定加工工艺路线72.5 重要工序尺寸、加工余量、精度的确定82.5.1 50孔82.5.2 2X12孔82.5.3底面的加工92.6 机床以及刀具的选择92.6.1 机床的选择92.6.2 刀具的选择92.7 主要切削用量的确定9第3章 夹具设计133.1机床夹具概述133.2工件在夹具中的定位143.3被加工零件的结构特点及制定工序的加工要求163.4定设计方案的讨论183.5 切削力及夹紧分析计算193.6夹具的夹紧装置和定位装置203.7误差分析与计算223.8对刀装置设计223.9 夹具操作步骤分析和可靠性预测233.10 编写主要夹具非标准零件的加工工艺规程23总结25参考文献25绪论1.1 设计任务本次设计的任务分为两个部分,一是开合螺母下座体的加工工艺流程,主要包括分析任务给定工件尺寸要求,形位要求,表面粗糙度的要求,以及制定一套工艺流程使工件达到任务要求。二是设计夹具。1.2 任务分析工艺部分先要考虑加工工件的结构特点以及生产批量,并按照其结构特点考虑在加工的过程中用何种手段能实现工件各个面、孔的加工,在提高效率的同时还要保证保证加工精度。夹具部分重点考虑的两个部分一个是定位,另一个则是加紧,定位部分的设计需要保证工件在夹具上处于完全定位,即6个方向上的自由度完全被限定,加紧则需要保证工件在切削力的作用下依然能在正确位置不发生偏移,并且夹紧力的施加需要保证不能破坏工件。1.3 与论文有关的部分背景资料调研1.3.1 开合螺母下座体的用途开合螺母下座体又称为“对合螺母”,主要由上下两个半螺母构成,装在机床溜板箱体后壁的导轨中。开合螺母下座体的底部各有一个圆孔,圆孔与槽盘的滑槽相连接。扳动机床手柄,经轴带动槽盘顺时针或逆时针转动,通过销钉的作用与上下两个开合螺母下座体使其分离或者闭合,从而与开合螺母下座体中的丝杠啮合或脱开,从而起到一个相当于“离合器”的作用,完成机床从手动到机动的转换1.3.2 工艺流程工艺流程指的是劳动者通过生产工具将各类原料、半成品,按照一定的顺序进行连续加工,最终使其成为成品的过程工艺流程的设计应当遵循以下基本要求:1、能满足产品的质量以及数量的指标。2、符合经济性。3、具有合理性。4、环保。5、生产过程具有可操作性。6、生产过程具有可控制性。我国近年更加注重以下几个方面:1、尽量采用先进成熟的生产设备与生产技术。2、尽量采取机械化自动化。3、减少三废的排放。4、保障安全生产。1.3.3 夹具夹具是指机械加工中用来固定加工工件使之具有正确的位置,以便于接受施工或者检测设备。本次设计的是一种用于车床上的加工工件内回转面的夹具,安装于车窗主轴上。第2章 工艺部分2.1 引言 本章主要任务是分析任务给定图样的技术要求,加工零件的各尺寸精度、形状精度、位置精度和表面粗糙度达到图纸要求。并编制零件加工工艺流程、填写零件加工工艺卡片以及说明书。2.2开合螺母下座体的结构分析图1 本次任务给定的开合螺母下座体由左右两个结构对称的半螺母组成,底部有55的燕尾,燕尾凸台地面有2X12 ,孔深18,开合螺母下座体中间开50的根部留有空刀槽。 燕尾凸台B1 B2以及C面表面质量要求2.6,燕尾凸台底面2个12光孔要求达到7级精度内表面质量要求2.6,孔间距0.05,50孔要求达到7级精度。图22.3工艺分析 将开合螺母下座体的加工分为两类: 1.轴类(外表面)的加工 主要加工面有长度尺寸为75.2mm的底面,两个倒角,B1,B2,C面,开合螺母下座体圆筒部左右两个端面,50中心线到燕尾凸台底面330.05mm,中线到左边端面距离49,上表面总长96,下表面总长105燕尾凸台底面到C面距离18。 2.孔类(内表面)的加工 主要有50以及两个12的孔,12孔间距要求达到0.052.4制定工艺规程2.4.1 确定毛坯的型式 任务给定工件轮廓不大,大批量生产,加工条件较高,选择离心铸造毛胚。离心铸造得来的铸件具有紧密与微细的颗粒结构及较好的机械性能。材料选用灰口铸铁HT150其铸造性能良好,减摩性好;减震性强;切削加工性良好;缺口敏感性较低;价格便宜,制造方便。2.4.2 基准面的选择 基准面是用来作为基准以确定其他点、线、面尺寸之间尺寸的平面,所以选择正确的基准面可以提高生产效率,保证加工质量。开合螺母下座体的加工当以底面以及两个直径12的光孔为精基准,而为精基准的表面应该提前加工完。粗基准选择的重点应当是如何确保加工面有足够的余量,使得不加工面的位置尺寸符合任务给定的要求。因此依据粗基准选择原则,选取R34的大外圆为粗基准来加工燕尾槽导轨面,然后以燕尾槽为面为基准加工50的螺孔。2.4.3 工艺路线的制定 开合螺母下座体的形状比较复杂,需要加工的表面不便于集中加工,为保障大批量生产的效率,需要在各个工序中选用高效率的专用机床,采取工序分散的原则拟定路线。2.4.4 加工方法的选择 依据机械制造工艺学表A-5、A-6以及零件图精度要求查询经济加工精度,选择主要加工面的加工方法 加工面 表面质量要求 精度 加工方法孔50 2.6 IT7 粗镗-半精镗-精镗孔12 2.6 I77 钻-扩-粗绞-精绞 C B1 B2 2.6 无 粗刨-半精刨-精刨圆筒端面 2.6 无 粗铣-半精铣底平面 6.3 无 粗铣-半精铣2.4.5加工的顺序安排 依据零件图,质量要求比较高,一道工序显然不可以满足质量要求,所以需要多道工序逐步达到质量要求,依照加工性质的不同,将加工顺序分为,粗加工、半精加工、精加工三个阶段。粗加工:切除毛坯大部分加工余量。使毛坯大体上接近于成品半精加工:留出精加工的加工余量为精加工做好准备。精加工:保证各个主要加工面达到图纸要求。2.4.6 加工过程中应当遵循的原则: a.先粗后精 先安排粗加工工序,再安排精加工工序。 b.基面先行 先将底平面加工,然后以底平面和R34大圆弧为基准加工孔12 c.加工过程中应该先加工平面,后加工孔,这样利用加工后的平面定位稳定 可靠,而且容易加工,提高孔的加工精度。2.4.7 制定加工工艺路线工序号工序名称工序内容设备1铸铸造毛坯(两件合一)2热处理时效处理3刨1. 粗、半精刨燕尾槽;2. 粗、半精刨C基准面牛刨4铣1. 铣两端侧面;卧式铣床5车1. 粗、精车R37面;2. 钻、扩55(留余量);3. 调头粗、精车另外一侧R37面卧式铣床6钻1. 钻孔2-6.5锪锥孔90钻另一孔72. 钻、扩、铰2-12H7钻床7铣切割,控制尺寸5卧式铣床8钳去毛刺9检检验10磨磨燕尾槽(两件合一)磨床11检总检12清洗、入库2.5 重要工序尺寸、加工余量、精度的确定2.5.1 50孔 最终需要加工至尺寸50,查互换性测量技术可得7级精度查机械制造工艺学需要经过一次粗镗,二次粗镗,半精镗,精镗,可以达到要求 查表金属机械加工表4-17查出镗孔各工序尺寸以及工序间余量粗镗阶段,第一次粗镗至47(IT13) 第二次粗镗至50(IT12) 半精镗阶段,半精镗至50.5(IT10)精镗阶段, 精镗至 50(IT7)工序间加工余量:粗加工阶段5mm 半精加工阶段 2.5mm 精加工阶段 0.5mm 则镗50孔总加工余量为6mm2.5.2 2X12孔 最终需要加工尺寸至12,查互换性测量技术可得7级精度查机械制造工艺学需要经过钻孔 扩孔 粗绞 精绞可以达到要求其中可以将钻孔、扩孔视为粗加工阶段 查表金属机械加工表4-15查出绞孔各工序尺寸以及工序间余量 粗绞、精绞视为半精加工、精加工阶段 钻孔阶段 钻孔至 11(IT11) 扩孔阶段 扩孔至 12.85(IT11) 粗绞阶段 粗铰至12.95(IT9) 精绞阶段 精铰至 12(IT7) 工序间加工余量(排除钻孔)扩孔0.85mm 粗绞0.1mm 精绞0.05mm 则加工12孔总余量为1mm2.5.3底面的加工 查表金属机械加工表4-28查出平面加工工序尺寸以及工序间余量 精刨B1 B2 C面后,下底面到C面尺寸达到18.0mm,加工余量0.5mm,故此,半精刨加工时下底面到C面尺寸为17.5(IT8)。 粗铣底平面,加工余量2.5mm 则粗铣前,总高度应为84.5(IT11)(毛坯尺寸)2.6 机床以及刀具的选择2.6.1 机床的选择 工序10、25、45 为铣削加工,工步少,依据工件尺寸选择X6132立式铣床 工序20、40 为钻孔、扩孔、绞孔加工,依据工件尺寸选择Z5125A立式钻床 工序35、55 为粗镗、精镗、半精镗加工,依据工件尺寸选择C620车床 工序30、50 为粗刨、半精刨、精刨加工,依据工件尺寸选择B6025刨床2.6.2 刀具的选择 底面铣削选择硬质合金刀端面铣刀。 钻孔12mm时,选用直柄麻花钻。 铣削端面时选择硬质合金端面铣刀。 镗孔时选用硬质合金60内孔车刀 刨削,粗刨时选用平面刨刀,精刨时选用圆头精刨刀2.7 主要切削用量的确定 查询机械制造技术基础课程设计表5.15.30选择进给量、切削速度并计算出主轴转速。 工序10 粗、半精刨C基准面 在粗铣工序时,取加工余量为背吃刀量以提高铣削效率,所以a=2.5mm 取每齿进给量f=0.3mm/z 取切削速度V=34.6m/min 铣床主轴转速 n=1000v/d=1000*34.6/3.14*80=137r/min 工序40 半精铣粗、半精刨C基准面 半精铣时,背吃刀量取0.5mm至2mm,故背吃刀量a等于半精铣工序时的加 工余量=1mm 取每齿进给量f=0.2mm/z 取切削速度V=40m/min 铣床主轴转速 n=1000*40/(3.14*80)=159r/min 工序25 粗铣左右两侧端面 在粗铣工序时,取加工余量为背吃刀量以提高铣削效率,所以a等于粗铣工序时的加工余量=3mm 查手册 取每齿进给量f=0.3mm/z 取切削速度V=34.6m/min 铣床主轴转速n=1000*34.6/(3.14*65)=170r/min 工序50 半精铣左右两端面 半精铣时,背吃刀量取0.5mm至2mm,背吃刀量a等于半精铣工序时的加工余量=1mm 取每齿进给量f=0.2mm/z 取切削速度V=40m/min 铣床主轴转速 n=1000*40/(3.14*65)=196r/min 工序20 钻孔、扩孔 工步1 钻孔至11 第一次钻孔加工余量为11mm,一次行程钻完,故选择背吃刀量a等于钻孔工步时的加工余量=11mm 工件材料HT150,布氏硬度180HBS,选择进给量f=0.45mm/r 选择切削速度V=0.45mm/r 钻床主轴转速n=60000V/(d)=60000*0.45/(3.14*11)=782.7r/min 工步2 扩孔至12 扩孔时加工余量0.85mm,一次行程扩完,故选择背吃刀量a等于扩孔工步时的加工余量=0.85mm 工件材料HT150,布氏硬度180HBS,选择进给量f=0.8mm/r 选择切削速度V=0.18m/s 钻床主轴转速n=60000V/(d)=60000*0.18/(3.14*12.85)=290.2r/min 工步2精绞孔至12 精绞孔的加工余量为0.05mm,一次行程绞完。背吃刀量a等于精绞孔工步时的加工余量=0.05mm 选择进给量f=2.5mm/r 切削速度V=10m/min 主轴转速 n=1000V/(d)=1000*10/(3.14*12)=267r/min=266r/min 工序35 粗镗50 在粗镗工序时,取加工余量为背吃刀量以提高铣削效率,所以a=5mm 选择进给量为f=0.5mm/r 取削速度为V=0.5m/s 车床主轴转速n=60000V/(d)=60000*0.5/(3.14*40)=238.8r/min 工序60 半精镗、精镗大孔 工步1 半精镗 半精镗工序时,背吃刀量通常取0.52.5mm,故取背吃刀量a等于半精镗工序时的加工余量=2.5mm 选择进给量为f=0.4mm/r 切削速度为V=0.6m/s 车床主轴转速n=60000V/(d)=60000*0.6/(3.14*40)=286.6r/min 工步2 精镗 取背吃刀量a等于精镗工序时的加工余量=0.5mm 选择进给量为f=0.3mm/r 切削速度为V=0.4m/s. 车床主轴转速n=60000V/(d)=60000*0.4/(3.14*40)=192.1r/min14第3章 夹具设计见夹具说明书 工序号工序名称工序内容设备1铸铸造毛坯2热处理时效处理3铣1. 铣底面2. 铣与定位键配合的面卧式铣床X61324铣铣上表面各个小凸台立式铣床X50K5铣铣夹具体两侧U型槽立式铣床X50K6钻1. 钻M8底孔6.82. 钻两M6底孔53. 钻两M5底孔4.24. 钻10孔5. 钻四个5孔6. 钻两6销孔钻床7攻螺纹1. 攻两M82. 攻两M63. 攻两M5钻床8钳去毛刺9检检验10检总检11清洗、入库清洗、入库总结通过为期一个半星期的课程设计使我加深了对机械制造基础这一门课程实用性的理解,也是我明白了工厂里面工人操作流程,对于一个产品的生产流程,加工工艺规程,我有了一些粗层次的了解,我认为出去以后当我看到那一张张工序卡片,工艺卡片,我一定能看懂它,感谢有这样一次机会!感谢我们团体成员为这次课程设计所付出的辛勤努力,以及傅老师的指导。参考文献1 卢秉恒.机械制造技术基础.北京:机械工业出版社,2007.12.2 孟少农.机械加工工艺手册M.北京:机械工业出版社,1991.3 柯建宏,宾鸿赞.机械制造技术基础课程设计.华中科技大学出版社,2006.4郑修本.机械制造工艺学M.北京:机械工业出版社,1999.5 邹青.机械制造技术基础课程设计指导教程.机械工业出版社,2004.1.外文翻译机械加工零件的工艺及夹具设计摘 要:本文对机械加工零件的结构和工艺进行了分析,确定了机械加工工艺路线,夹具在机械加工中所占的地位和重要性,以及夹具设计。随着科学的日益发展进步和国家产业政策的调整,工程机械行业已成为没有政策壁垒的完全竞争行业关键词:技术背景/发展趋势/工序/定位方案1 机械加工历史背景及其意义机械制造业是一个古老而永远充满生命力的行业。随着现代工业的发展,对机械产品的要求越来越高,机械制造工艺也在日新月异地发展。自新中国成立以来,我国的制造技术与制造业得到了长足发展,一个具有相当规模和一定技术基础的机械工业体系基本形成。改革开放二十多年来,我国制造业充分利用国内国外两方面的技术资源,有计划地推进企业的技术改造,引导企业走依靠科技进步的道路,使制造技术、产品质量和水平及经济效益发生了显著变化,为推动国民经济的发展做出了很大的贡献。尽管我国制造业的综合技术水平有了大幅度提高,但与工业发达国家相比,仍存在阶段性差距。进入二十一世纪,我国发展经济的主导产业仍然是制造业,特别是在我国加入世贸组织后,世界的制造中心就从发达国家迁移到了亚洲,我国有廉价的劳动力和广大的消费市场,因此,我国工业要想发展,就需要有相应的技术和设备来支持。机械工业是国民经济的装备工业;是科学技术物化的基础;是高新技术产业化的载体;是国防建设的基础;是实现经济快速增长的重要支柱;也是为提高人民生活质量、提供消费类机电产品的供应工业。它对国民经济运行的质量和效益、产业结构的调整和优化具有极其重要的作用。2 机械行业的现状及发展趋势随着社会的发展,各种机械逐渐运用到各个行业中,不管是在农用、军用、工用等方面,离开了机械的操作就谈不上效率,因此,从某中角度上来说,一个国家的经济实力、社会地位,和机械行业的发展是密不可分的。各工业化国家经济发展的历程表明,没有强大的装备制造业,就不可能实现国民经济的工业化、现代化和信息化3。目前装备制造业发展滞后是制约我国经济发展和产业升级的重要因素,加大结构调整力度,推进机械工业持续、健康、稳定发展,对于转变经济增长方式,提高国民经济整体素质,增强我国经济的国际竞争力,保障国防安全等都具有重要而深远的意义。3 机械加工工艺规程制订3.1 机械加工工艺过程的定义机械加工工艺过程是指用机械加工方法改变毛坯的形状,尺寸,相对位置和性质等,使其成为成品或半成品的全过程。机械加工工艺过程直接决定零件及产品的质量和性能,对产品的成本、生产周期都有较大的影响,是整个工艺过程的重要组成部分。3.2 机械加工工艺过程的组成组成机械加工工艺过程的基本单元是工序。工序又是由安装、工位、工步及走刀组成的。 工序是指一个或一组工人,在一个工作地对同一个或同时对几个工件所连续完成的那一部分工艺过程。工序是制定劳动定额、配备工人及机床设备、安排作业计划和进行质量检验的基本单元。 安装是工件经一次装夹后所完成的那一部分工序。 当应用转位(或移位)加工的机床(或夹具)进行加工时,在一次装夹中,工件(或刀具)相对于机床要经过几个位置依次进行加工,在每一个工作位置上所完成的那一部分工序,称为工位。采用多工位加工可以减少装夹的次数,减少装夹误差,提高生产率。 工步是加工表面在切削刀具和切削用量(仅指主轴转速和进给量)都不变的情况下所完成的那一部分工艺过程。 在一个工步中,如果要切掉的金属层很厚,可分几次切削,每切削一次就称为一次走刀。3.3 机械加工工艺规程的定义规定产品或零部件制造过程和操作方法等的工艺文件,称为工艺规程,它是企业生产中的指导性技术文件。3.4 机械加工工艺规程的作用及内容机械加工工艺规程是生产准备工作的主要依据。根据它来组织原材料和毛坯的供应,进行机床调整,专用工艺装备的设计与制造,编制生产作业计划,调配劳动力,以及进行生产成本核算等。机械加工工艺规程也是组织生产、进行计划调度的依据。有了它就可以制定生产产品的进度计划和相应的调度计划,并能做到各工序科学地衔接,使生产均衡、顺利,实现优质、高产和低消耗。机械加工工艺过程卡片和机械加工工序卡片,是两个主要的工艺文件。机械加工工艺过程卡片,是说明零件加工工艺过程的工艺文件。在单件、小批量生产中,以机械加工工艺过程卡片指导生产,过程卡的各个项目编制较为详细。机械加工工序卡片是为每个工序详细制定的,用于直接指导工人进行生产,多用于大批量生产的零件和成批生产中的重要零件。3.5 制订机械加工工艺规程的原则及步骤在一定的生产条件下,以最少的劳动消耗和最低的费用,按计划加工出符合图纸要求的零件,是制订机械加工工艺规程的基本原则。制订机械加工工艺规程的步骤如下:根据零件的生产纲领决定生产类型;分析零件加工的工艺性;选择毛坯的种类和制造方法;拟订工艺过程;工序设计;编制工艺文件。4 夹具设计4.1 夹具设计的意义在机械行业中,如何去保证工件的高精度、加工的成本等实质性问题,一直是从事于机械行业人员研究的问题,其中在设计夹具的时候就要考虑以上问题,高效的夹具是工件高精度的保证,如何让夹具更高效、更经济,这是行业人急需要解决的。随着社会的发展,科技的不断提高,各种高科技技术逐渐渗透到各个行业,如何利用这些高科技为人类服务,如何充分利用这些高科技在机械行业中,这还需要机械行业人员不断的努力,开拓创新。随着科学技术的发展,和社会市场需要,夹具的设计在逐步的超向柔性制造系统方向发展。迄今为止,夹具仍是机电产品制造中必不可缺的四大工具之一,刀具本身已高度标准化,用户只需要按品种、规格选用采购。而模具和夹具则和产品息息相关,产品一有变化就需重新制作,通常是属于专用性质的工具,模具已发展成为独立的行业;夹具在国内外也正在逐渐形成一个依附于机床业或独立的小行业。 组合夹具不仅具有标准化、模块化、组合化等当代先进设计思想,又符合节约资源的原则,更适合绿色制造的环境保护原理。所以是今后夹具技术的一个重要发展方向单位 。机床夹具通常是指装夹工件用的装置:至于装夹各种刀具用的装置,则一般称为“辅助工具”。辅助工具有时也广义地包括在机床夹具的范围内。按照机床夹具的应用范围,一般可分为通用夹具,专用夹具和可调整式夹具等。通用夹具是在普通机床上一般都附有通用夹具,如车床上的卡盘,铣床上的回转工作台,分度头,顶尖座等。它们都一标准化了,具有一定的通用性,可以用来安装一定形状尺寸范围内的各种工件而不需要进行特殊的调整。但是,在实际生产中,通用夹具常常不能够满足各种零件加工的需要;或者因为生产率低而必须把通用夹具进行适当的改进;或者由于工件的形状,加工的要求等的不同须专门设计制造一种专用夹具,以解决生产实际的需要。用夹具是为了适应某一工件的某一工序加工的要求而专门设计制造的,其功用主要有下列几个方面:1.保证工件被加工表面主要包括加工工件所需要的机动时间和装卸工件等所需要的辅助时间两部分。2.采用专用夹具后,安装工件和转换工位的工作都可以大为简化,不再需要画线和找正,缩短了工序的辅助时间并且节省了画线这个工序,从而提高了劳动生产率.在生产中由于采用了多工件平行加工的夹具,使同时加工的几个工件的机动时间将与加工一个工件的机动时间相同。采用回转式多工位连续加工夹具,可以在进行切削加工某个工件的同时,进行其它工件的装卸工作,从而使辅助时间与机动时间相重合。总之,随着专用夹具的采用和进一步改善,可以有效地缩短工序时间,满足生产不断发展的需要。3.采用专用夹具还能扩大机床的工艺范围。例如在普通车床上附加镗模夹具后,便可以代替镗床工作;装上专用夹具后可以车削成型表面等,以充分发挥通用机床的作用。4.减轻劳动强度,保障安全生产。根据生产需要,采用一些气动,液压或其它机械化,自动化程度较高的专用夹具,对于减轻工人的劳动强度,保障生产安全和产品的稳质高产都有很大作用。加工大型工件时,例如加工车床床身上,下两面上的螺孔,需要把床身工件翻转几次进行加工,劳动强度大而且不安全。采用电动回转式钻床家具后,就能够达到提高生产效率,减轻劳动强度,保障生产安全的目的。4.2 夹具的发展趋势工业设计是人类社会发展和科学技术进步的产物,从英国莫里斯的“工艺美术运动”,到德国的包豪斯设计革命以及美国的广泛传播与推广,工业设计经过了酝酿,探索,形成,发展百余年的历史沧桑。时至今日,工业设计已成为一门独立的专业学科,并且有一套完整的研究体系。1980年国际工业设计协会理事会(ICSID)给工业作了明确定义:“就批量生产的工业产品而言,凭借训练,技术知识,经验及视觉感受,而预示材料、结构、构造、形态、色彩、表面加工,装饰以新的品质和规格,叫做工业设计。根据当时的具体情况,工业设计师应在上述工业产品全部侧面或其中几个方面进行工作,而且需要工业设计师对包装、宣传、展示,市场开发等问题的解决付出自己的技术知识和经验以及视觉评价能力时,这也属于工业设计的范畴”。材料、结构、工艺是产品设计的物质技术基础,一方面,技术制约着设计;另一方面,技术也推动着设计。从设计美学的观点看,技术不仅仅是物质基础还具有其本身的“功能”作用,只要善于应用材料的特性,予以相应的结构形式和适当的加工工艺,就能够创造出实用,美观,经济的产品,即在产品中发挥技术潜在的“功能”。 任何设计都是时代的产物,它的不同的面貌,不同的特征反映着不同历史时期的科学技术水平。技术是产品形态发展的先导,新材料,新工艺的出现,必然给产品带来新的结构,新的形态和新的造型风格。材料,加工工艺,结构,产品形象有机地联系在一起的,某个环节的变革,便会引起整个机体的变化。现在,机械加工工艺及夹具随着制造技术的发展也突飞猛进。机械加工工艺以各个工厂的具体情况不同,其加工的规程也有很大的不同。突破已往的死模式。使其随着情况的不同具有更加合理的工艺过程。也使产品的质量大大提高。制定加工工艺虽可按情况合理制定,但也要满足其基本要求:在保证产品质量的前提下,尽可能提高劳动生产率和降低加工成本。并在充分利用本工厂现有生产条件的基础上,尽可能采用国内、外先进工艺技术和经验。还应保证操作者良好的劳动条件。但我国现阶段还是主要依赖工艺人员的经验来编制工艺,多半不规定工步和切削用量,工时定额也凭经验来确定,十分粗略,缺乏科学依据,难以进行合理的经济核算国际生产研究协会的统计表明,目前中、小批多品种生产的工件品种已占工件种类总数的85左右。现代生产要求企业所制造的产品品种经常更新换代,以适应市场的需求与竞争。然而,一般企业都仍习惯于大量采用传统的专用夹具,一般在具有中等生产能力的工厂里,约拥有数千甚至近万套专用夹具;另一方面,在多品种生产的企业中,每隔34年就要更新5080左右专用夹具,而夹具的实际磨损量仅为1020左右。特别是近年来,数控机床、加工中心、成组技术、柔性制造系统(FMS)等新加工技术的应用,对机床夹具提出了如下新的要求:1)能迅速而方便地装备新产品的投产,以缩短生产准备周期,降低生产成本;2)能装夹一组具有相似性特征的工件;3)能适用于精密加工的高精度机床夹具;4)能适用于各种现代化制造技术的新型机床夹具;5)采用以液压站等为动力源的高效夹紧装置,以进一步减轻劳动强度和提高劳动生产率;6)提高机床夹具的标准化程度。现代机床夹具的发展趋势主要表现为标准化、高效化、精密化和柔性化等四个方面。利用更好的夹具,可以提高劳动生产率,提高加工精度,减少废品,可以扩大机床的工艺范围,改善操作的劳动条件。因此,夹具是机械制造中的一项重要的工艺装备。一个好的夹具是加工出合格产品的首要条件,为了让夹具有更好的发展,夹具行业应加强产、学、研协作的力度,加快用高新技术改造和提升夹具技术水平的步伐,创建夹具专业技术网站,充分利用现代信息和网络技术,与时俱进地创新和发展夹具技术。主动与国外夹具厂商联系,争取合资与合作,引进技术,这是改造和发展我国夹具行业较为行之有效的途径。参考文献1:裘愉,组合机床,北京:机械工业出版社,1995.2:金振华.组合机床及其调整与使用.北京:机械工业出版社,1990.3:沈延山.生产实习与组合机床设计.大连:大连理工大学出版社,1989.4:上海市大专院校机械制造工艺学协作组编著.机械制造工艺学.福建科学技术出版社,1996.5:王华坤,范元勋.机械设计基础.北京:兵器工业出版社,2000.6:冯辛安.机械制造装备设计.北京:机械工业出版社,1998.7:陈日曜.机械原理.北京:机械工业出版社,1992.8:方子良.机械制造技术基础.上海:上海交通大学出版社,2004.9:刘秋生,李忠文.液压传动与控制.北京:宇航出版社,1994.10:陈于萍,周兆元.互换性与测量技术基础.北京:机械工业出版社,2005.11:东北重型机械学院等.机床夹具设计手册.上海:上海科技技术出版社,1979.12:机械设计手册联合编写组.机械设计手册.北京:机械工业出版社,1987.13:王先逵.机械制造工艺学(上下册).北京:清华大学出版社,1989.14:崇凯.机械制造技术基础课程设计指南. 15:黄如林,汪群.金属加工工艺及工装设计. 16:鲁屏宇.工程图学.17:冯辛安.机械制造装备设计.18:Gell Maurice Materials Science and Engineering,1995,A204:24625119:X. Chen, J.W. Hutchinson, M.Y. He, A.G. Evans, Acta Mater. 51 (2003) 2017.Mechanical Parts Processing Technology and Fixture Design Pick to : the machining parts of the structure and process analysis, identified the machine- finishing craft route, fixture in the mechanical processing of the status and importance, as well as the fixture design. With the increasingly development of scientific progress and the adjustment of national industry policy, project machinery industry already became no policy barriers of perfectly competitive industry Key words: technical background / development / process / positioning scheme 1 Mechanical Processing Historical Background and Its Significance Machinery manufacturing industry is an old and eternal industry full of vitality. With the development of modern industry, the mechanical product of the increasingly high demand, machinery manufacturing technology are developing rapidly. Since the founding of new China, our countrys manufacturing technology and manufacturing industry to obtain the considerable development, a considerable size and technical basis of mechanical industry system is formed basically. Years of reform and opening up, Chinas manufacturing industry to make full use of domestic and foreign two aspects of technological resources, there are plans to promote the technical transformation of enterprises, guide enterprises to take the road to rely on progress of science and technology, manufacturing technology, product quality and level and the economic benefit produced marked change, in order to promote the development of the national economy has made great contribution. Although our country manufacturing industry comprehensive technical level has been greatly improved, but compared with developed country, still have level sex difference. Enter the twenty-first Century, the economic development of our country s leading industry still is the manufacturing industry, especially after our country joins WTO, the worlds manufacturing center is developed from migration to Asia, China has cheap labor and the general consumer market, accordingly, industry of our country wants to develop, need to have appropriate technology and equipment support. Machinery industry is the equipment industry of national economy; it is content of science and technology of foundation; is new and high technology industrialization; is the basis of national defense building; is to achieve rapid economic growth of the important pillar; is to improve peoples living quality, provide consumer electrical products supply industry. It runs to national economy, the quality and efficiency of industrial structure adjustment and optimization is a very important role. 2 The Status of Machinery Industry and Development Trend With the development of society, all kinds of machinery and gradually applied to the various industry, whether in the agricultural, military, industrial, mechanical operation, leaving no efficiency, therefore, in some sense, the strength of a countrys economy, social status, and the development of machinery industry is close separable. The industrialized countries economic development course indicated that, without a strong equipment manufacturing industry, is impossible to achieve national economy industrialization, modernization and information 3 . At present, the equipment manufacturing industry development lag is restricting Chinas economic development and industrial upgrading of the important factors, increase structural adjustment strength, promote mechanical industry lasts, healthy, steady development, to change the mode of economic growth, improve quality of national economy whole, enhance the international competitiveness of the economy, security and national defense security has important and far-reaching meaning of. 3 Of Machining Process Planning 3.1 Machining Process Definition The machining process is the use of mechanical processing method of change in rough shape, size, the relative position and the nature, make its become finished or semi-finished products of the whole process. Machining process directly determines the parts and the quality and performance of products, product cost, production period has great influence, is an important part of the whole process. 3.2 Mechanical Processes The composition of mechanical machining process of the basic unit is a process. Process and is formed by mounting, station, working steps and take the knife. The process is a group of workers, in a work of the same or simultaneously on several workpieces are completed for that part of the process. Process is the formulation of labor quota, with workers and machine tool equipment, arranging operation plan and quality testing of the basic unit. The installation is a workpiece by a fixture after the completion of the procedures. The application of switch ( or displacement) when processing machine tool ( or fixture ) processing, in a fixture, the workpiece ( or cutter ) relative to the machine tool passes through several locations in order processing, in each position is done on that part of the process, called station. The multi-station processing can reduce the times of clamping, reduce the mounting error, improve productivity. The step is processing the surface in the cutting tool and the cutting parameters ( only refers to the spindle speed and feed rate ) are the same circumstances completed part of the process. 3.3 Machining Process Definition Products or components manufacturing process and operation methods of the process, called process, it is the enterprise in the production of technical guidance document. 3.4 Machining Process Planning Function and Content Machining process is ready for production work mainly on the basis of. According to its raw material and semifinished product supply, machine tool adjustment, special process equipment design and manufacturing, production scheduling, allocation of labor force, and the production cost accounting. The machining process planning and organization of production, planning and scheduling based on. It can make production schedule and the corresponding scheduling, and can be connected to the scientific process, production is balanced, smooth, to realize high quality, high yield and low consumption. Machining process card and machining process card, are the two main process documents. Machining process card, is illustrated parts machining process technology files. In a single, small batch production, to machining process card guiding production, process card various projects in the preparation of more detailed. Machining process card for each process detailed formulation, used to direct workers, used for mass production parts and mass production of the important parts in the. 3.5 Making The Machining Process Planning Principles and Steps Under certain production conditions, with minimal consumption of labor and the lowest cost, according to plans processing parts that meet requirements of the drawings, is to develop the basic principle of machining process. Formulation of machining process steps are as follows: The under parts of the production program decision production type; The analysis of parts processing technology; The choice of blank type and manufacturing method; The technological process; The process design; The process documentation. 4 Fixture Design 4.1 Fixture Design Sense In the machinery industry, how to guarantee the high precision of workpiece, the costs of processing and other substantive issues, has been engaged in the mechanical industry research questions, which in the design of fixture when we should consider the problems above, efficient fixture is the workpiece precision guarantee, how to make the fixture more efficient, more economical, the industry is the urgent need to resolve. With the development of society, the continuous improvement of technology, various high- tech technology gradually infiltrated into all sectors, how to use these high-tech to serve mankind, how to make full use of the technology in mechanical industry, it also requires machinery industry staff continued efforts, innovation. With the development of science and technology, and social needs of the market, the fixture design in progressive super to the flexible manufacturing system development. To date, the fixture is mechanical and electrical products manufacturing in the four indispensable tools, tool itself is already highly standardized, the user only needs to press varieties, specifications selection and procurement. While the mold and fixture and related products products, there is a need to make changes, usually belong to the special properties of the tool, mould has become an independent industry; fixture at home and abroad is also gradually form a dependent or independent small industry of machine tool industry. Combined clamp not only has the standardization, modularization, modular and other contemporary advanced design ideas, and in line with resource conservation principle, more suitable for green manufacturing environment protection principle. So the next fixture technology is an important direction of development unit. Machine tool fixture is usually refers to the use of clamping workpiece clamping device: for the device with various tools, also known as tool. The auxiliary tool is sometimes generalized to include in the range of machine tool fixture. According to the application range of machine tool fixture, generally can be divided into general jig, fixture and adjustable fixture. Universal jig is on general machine tools are generally accompanied by a common fixture, such as a lathe chuck, milling machine rotary table, dividing head, top seat. They have a standardized, with certain universality, can be used to install certain shape and size within the range of the workpiece without the need for special adjustment. However, in actual production, a universal fixture often can not meet the needs of various parts processing; or because of low productivity and must have the universal fixture for proper improvement; or because the shape of the workpiece, the processing requirements to be different specialized design and manufacture of a special jig, in order to solve the actual production needs. Jig is adapted to a workpiece in a processing requirements and the design and manufacturing expertise, its function mainly has the following several aspects: 1 ensure that the surface of the workpiece being processed mainly includes processing workpieces need maneuvering time of loading and unloading workpieces need the auxiliary time of two part. 2 using a dedicated fixture, workpiece installation and conversion work work can be greatly simplified, no longer need to draw the line and to find it, to shorten the working procedure non-cutting time and save line drawing this process, thereby improving the labor productivity. In production due to the adoption of multiple parallel processing workpiece fixture, enabling the simultaneous processing several parts of the motor will time and processing time of the same motor. The rotary multi-station continuous processing fixture, can be used for machining a workpiece at the same time, other workpiece loading and unloading, thereby enabling the auxiliary time and motor time coincides. In short, with the special fixture using and further improvement, can effectively shorten the process time, production to meet the evolving needs of. 3 using a dedicated fixture can expand the scope of machine tool technology. For example in lathe boring jig attached, can replace boring work; special fixture can be installed after turning the molding surface, so as to give full play to the role of general machine tools. 4, reduce the labor intensity, and ensuring safety production. According to the demand of production, using pneumatic, hydraulic or other mechanical changes, a higher degree of automation of the special fixture, to reduce the labor intensity of workers, protection of production safety and the stability of product quality and high yield of a great role. Processing large workpieces, such as the lathe bed, the lower surfaces of the screw holes on the bed, need to flip several times for processing workpieces, high labor intensity and safety. The use of electric rotary drill furniture, can improve production efficiency, reduce labor intensity, ensure safety in production. 4.2 Fixture of The Development Trend Industrial design is the development of human society and the progress of science and technology of the product, from Maurices the arts and Crafts Movement, to the German Bauhaus design revolution and the United States of America wide dissemination and promotion, industrial design after brewing, exploration, formation, development history of more than 100 years of vicissitudes. Today, industrial design has become an independent subject, and a complete set of research system. In 1980 the International Council of societies of industrial design ( ICSID ) to the industry as a clearly defined: production of industrial products, by training, technical knowledge, experience and visual experience, and indicates the material, structure, morphology, structure, color, surface processing, decoration to the new quality and specification, called industrial design. According to the specific circumstances of the time, industrial designer in the industry products are all side or a few aspects of the work, but also the need for industrial designers of packaging, publicity, display, market development and other issues to resolve pay their own technical knowledge and experience and ability of the visual evaluation, which also belongs to the scope of industrial design. Material, structure, technology is the product design material and technical basis, on one hand, technology restrict the design; on the other hand, technology is also promoting design. From the point of view of design aesthetics, technology is not only the material basis but also has its own function action, as long as good application properties of the materials, to the corresponding structure and suitable processing technology, can create a practical, aesthetic, economic products, namely in the product technology potential function. Any design are the product of the times, its different features, different features reflect the different historical periods of level of science and technology. Technology is the product of the morphological development of the pilot, new material, new technology products, is bound to bring new structure, new forms and new style. Materials, processing technology, structure, product image organic ground is contacted together, a part of the change, it will cause the whole body changes. Now, the machining process and fixture with the development of manufacturing technology also make a spurt of progress. Machining process to the various factories in different circumstances, its processing procedures are very different. Break through the past death mode. Make it with different cases has more reasonable technological process. So that product quality greatly improved. Develop processing technology can be rational, but also to meet the basic requirements: guarantee product quality under the premise, as far as possible to improve labor productivity and reduce the processing cost. And to make full use of the existing factory production conditions, as far as possible, using domestic and foreign advanced technology and experience. Should also ensure that the good working conditions. But our country present stage still rely mainly on technology personnel experience to prepare process, often does not require step and cutting amount, man-hour quota is to be determined by experience, very rough, the lack of scientific basis, difficult to carry out reasonable economic accounting International Journal of production Research Association statistics show that, at present, small batch production of many varieties of workpiece varieties accounted for about 85% of the total number of the kind of workpiece. Modern manufacturing requirements of enterprises manufacturing products constantly upgrading, to meet the needs of the market and competition. However, the general enterprises are still accustomed to the traditional special fixture, generally in the medium having a production capacity of the plant, some have thousands or even nearly 10000 sets of special fixture; on the other hand, in the production of many varieties of the company, every 3 to 4 years to update 50 80% special jig, fixture actual wear only 10 20% or so. Especially in recent years, CNC machine tools, machining center, group technology, flexible manufacturing system ( FMS ), a new processing technology of machine tool fixture, proposed the following new requirements: 1) can rapidly and conveniently and equipment of new products put into production, so as to shorten the production cycle, reduce the production cost; 2) capable of clamping a group with similar characteristics of the workpiece; 3) can be applied to precision machining of high precision machine tool fixture; 4) can be applied to all the modern manufacturing technology of new machine tool fixture; 5) adopts the hydraulic station for power efficient clamping device, in order to further reduce the labor intensity and improve labor productivity; 6) improve the standardization degree of machine tool fixture. The development trend of modern machine tool fixture mainly for standardization, efficiency, precision and flexibility in four aspects. Use better fixture, can improve labor productivity, improve processing accuracy, reduce waste, machine tool technology can expand the scope, improve the operation of labor conditions. Therefore, the fixture machinery manufacturing is an important process equipment. A good fixture is the processing of qualified products of the first condition, in order to allow the clamp has the better development, fixture industry should strengthen the production, learning and research, collaborative efforts, accelerate the use of high technology to transform and upgrade the level of technology to create the pace of jig, fixture professional technology website, make full use of modern information and network technology, and when in keeping with the innovation and development of fixture technology. Active and foreign fixture manufacturer, for joint venture and cooperation, the introduction of technology, it is the reform and development of our country industry is more effective ways of fixture.
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