数控铣削加工精度与加工误差分析

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1、Today, the main task of the Conference is: fully implement XX XX years working conference, summary of XX years work, analysis of the existing problems and the situation, deploy XX years. The following report to the General Assembly on behalf of my company to do the work, please consider. Report cons

2、ists of three parts. Review the first part of XX years XX XX years production and management company working full shift the center of gravity and further consolidate and deepen the basis of cost control, control, improve the quality of management a critical year. A years to, in XX power annual works

3、hop spirit, and six a breakthrough and cost leading strategy of guidelines Xia, we tightly around full construction five type Enterprise this a Center, pay close attention to the safety, internal control cost, outside extension market, through all employees of common efforts, success achieved II per

4、iod engineering full completed, successfully completed the production business task, the work made has welcome of results and great of progress, company achieved has and good and fast across type development. A, and production business made fruitful results, promoted company career health developmen

5、t 1, and security situation good by control: face full into production Hou huge of safety pressure, through further implementation security responsibility, and strengthened daily management, and security management level get improve, in one fell swoop reverse has early continuous occurred non-stoppe

6、d of passive situation, annual safety situation good by control, not occurred personal, and fire, and major mechanical equipment, and traffic, and career health and pollution accident. General equipment accidents unit 1, 3 times the value of the annual appraisal, non stop 4 times, 8 times the value

7、of the annual appraisal, 1, comparing 07 are 3 times, corporate security control level has made considerable progress. 2, and run maintenance quality steadily improve: run management aspects, through further strengthened personnel skills training, analysis management in the of key link, developed an

8、d perfect work standard and implementation program, makes run management more specification ordered, management quality sharply upgrade, annual 33 times unit Kai stopped no errors, SSR-DS project debugging and four machine maintenance during, large operation and test not appeared any exception, crea

9、ted has 2nd, unit 453 days is nothing more than stopped run, 3rd, unit 350 days is nothing more than stopped run, more items security records; Unit maintenance aspects, after carefully planning, strictly construction, successfully completed has 5.276.10 line full stopped four machine maintenance, an

10、d #1 unit first a, level maintenance, annual the maintenance task, while, all maintenance security, and quality, and progress, and costs full by control, unit ignition, and grid once success, and repair Hou is nothing more than stopped accident, company plans maintenance management level get full up

11、grade, from essentially guarantee has equipment run of health stable. 3, the assets profitability increased significantly: in 2012 the数控铣削加工精度与加工误差分析 摘要：数控铣床又称CNC铣床，是一种加工功能很强的数控机床。数控铣削加工精度和加工误差是衡量加工零件质量的两个重要的方面。本文将主要针对数控铣削加工精度的影响因素与加工误差来源进行分析和研究，并有针对性地提出补偿措施。关键词：数控铣削；加工精度；加工误差Analysis on the NC mill

12、ing machining precision and the errorJinan Iron and Steel Group Co.Ltd Measure and Quality Inspection Center Dongjinwei 250101Abstract: also known as CNC milling machine, CNC milling machine is a CNC machine processing function is very strong. CNC milling machining precision and processing error are

13、 the two most important respects to measure machining parts quality. This thesis mainly discussed and analysed the factors effect to the CNC milling machining precision and processing error, and proposed the relevant measures to compensate the CNC milling machining precision and processing error. Ke

14、y words: CNC milling; Machining precision; Processing error数控铣床就是按照加工要求预先编制程序，由数字控制系统发出数字量作为指令信息对工件进行自动加工的铣床。在整个数字控制系统中将主轴起停、主轴变速、进退刀、刀具与工件相对位移等操作都用数字化来表示，大大的提高了整个加工过程中的稳定性，从而提高了数控铣削的加工精度，减小了加工误差。但是，由于存在数控铣床本身的精度和加工过程中的控制误差，所以，提高加工精度和降低加工误差仍是反映数控铣床加工能力的重要方面。一数控铣床的基本工作原理铣床的加工表面形状一般是由直线、圆弧或其他曲线所组成。普通铣

15、床操作者根据图样的要求，不断改变刀具与工件之间的相对位置，再与选定的铣刀转速相配合，使刀具对工件进行铣削加工，便可加工出各种不同形状的工件。数控机床加工是把刀具与工件的运动坐标分割成最小的单位量，即最小位移量，由数控系统根据工件程序的要求，使各坐标移动若干个最小位移量，从而实现刀具与工件的相对运动，以完成零件的加工。如图1所示的凸轮曲线L。要求刀具T沿工件的曲线轨迹运动进行铣削加工。图1 数控机床加工曲线的原理数控铣床加工时，根据工件图样工艺要求，将铣床各运动部件的移动量、速度及动作先后程序、主轴转速、转向及冷却等要求，以规定的数控代码形式编制程序单，并输入到机床专用计算机中。然后，数控系统根

16、据输入的指令，由机床专用计算机进行编译、运算和逻辑处理后，输出各种信号和指令，控制机床各个部分进行规定的位移和有序的动作。由数控系统送出的指令脉冲，经驱动电路控制和放大后，使伺服电动机转动，通过齿轮副(或直接)经滚珠丝杠，驱动铣床K、Y(头架滑板)和Z方向的工作台。再与选定的主轴转速相配合，便可加工出各种不同形状的工件。图2伺服电动机传动原理二数控铣床系统误差对加工误差和加工精度的影响及补偿1. 数铣工艺系统的几何误差。由于数控铣床系统中各组成环节的实际几何参数和位置相对于理想几何参数和位置也会发生偏离而引起误差，所以也会存在几何误差。例如螺距误差，在数控铣床的定位精度主要取决于丝杠，目前使用

17、的高精密滚珠丝杠也会存在一定的螺距误差。为了减小这种影响，一般采用螺距误差补偿，主要是将某轴的实际运动位置和高精度测量系统测量结果进行对比，并记录对比误差，这样数控系统可在该轴运动到该位置时自动进行误差补偿。又例如数控铣床关键部位加工精度决定了数铣工件的加工精度等级。目前简易型数铣其最小运动分辨率为0.01mm，运动精度和加工精度都在0.03mm以下，超精密型用于特殊加工其精度可达0.001mm以下。表1 数控铣床精度特征精度项目普通型精密型单轴定位精度mm0.02/全长0.005/全长单轴重复定位精度mm0.0080.003铣圆精度mm0.030.04/2000.015/200由上表可以看出

18、，定位精度和重复定位精度综合反映了该轴在加工过程中是否稳定可靠的工作。2. 数铣工艺系统受力变形引起的误差。数铣工艺系统在切削力、夹紧力、重力和惯性力等作用下会产生变形，从而破坏工艺系统各组成部分的相互位置关系，产生加工误差并影响加工过程的稳定性。补偿措施：(1)提高接触刚度，改善机床主要零件接触面的配合质量，如机床导轨及装配面进行刮研。(2)设辅助支承，提高局部刚度，如细长轴加工时采用跟刀架，提高切削时的刚度。(3)采用补偿或转移变形的方法。3. 数铣工艺系统受热变形引起的误差。在加工过程中，由于受切削热、摩擦热及工作场地周围热源的影响，工艺系统的温度会产生复杂的变化。在各种热源的作用下，工

19、艺系统会发生变形，导致改变系统中各组成部分的正确相对位置，使工件与刀具的相对位置和相对运动产生误差。补偿措施：(1)机床结构设计采用对称式结构。(2)采用主动控制方式均衡关键件的温度。(3)采用切削液进行冷却。(4)加工前先让机床空转一段时间，使之达到热平衡状态后再加工。(5)改变刀具及切削参数。(6)大型或长工件，在夹紧状态下应使其末端能自由伸缩(7)热变形补偿，例如通过测量机床主要部件的温度变化和热变形量，建立热变形量与温度的函数式并输入系统，在加工过程中通过温度测量进行相应的补偿。三数控编程工艺对加工误差和加工精度的影响及补偿措施1. 加工路线因素 （1）进退刀方式对工件轮廓加工精度影响

20、较大，由于存在刀具直径、机床进给速度突变等原因，所以尽可能采取圆弧切入切出。 （2）数铣加工尽量采用顺铣，有利于提高加工表面质量，同时也可以提高刀具寿命。但有些情况下却应该采用逆铣的方式：例如工件表面有硬化或夹砂时，需要采用逆铣， 可以防止刀具损伤；加工非金属材料特别是含纤维材料时，采用逆铣才可完全切断纤维，获得较高的加工精度。 图 3 顺铣和逆铣 a)顺铣 b)逆铣 （3）如下图中所示，在数铣孔的路线选择中，如果对位置精度要求不高的话，应选择a图中所示，采用了最短加工路线，但会产生Y向误差；如果对位置精度要求较高，则应选择b 图中所示加工路线，虽然加工路线较长，但避免了Y向误差。 图4 数铣

21、孔加工路线选择2. 编程原点的确定。编程原点存在尺寸公差换算所引起的误差，所以编程原点的选择直接影响零件加工误差和精度。补偿措施：（1） 为避免尺寸链换算，应选取数值计算简单的点。（2） 尽量选择精度较高的表面，（3） 尽可能选择设计基准或工艺基准。四工件本身和人为因素对数铣加工精度和加工误差的影响和补偿1. 工件内应力引起的加工误差。内应力是工件自身的误差因素。工件经过冷热加工后会产生一定的内应力。通常情况下，内应力处于平衡状态，但对具有内应力的工件进行加工时，工件原有的内应力平衡状态被破坏，从而使工件产生变形。补偿措施：(1)合理设计零件结构，设计零件时尽量简化零件结构(2)合理安排工艺过

22、程，如粗精加工分开，使粗加工后有充足的时间让内应力重新分布，保证工件充分变形，再经精加工后，就可减少变形误差。(3)对工件进行热处理和时效处理。2. 测量误差。在工序调整及加工过程中测量工件时，由于测量方法、量具精度及工件和环境温度等因素对测量结果准确性的影响而产生的误差，都统称为测量误差。结论除了上述数铣机床本身系统误差和编程工艺误差、人为误差外，还有其他一些因素，在实际的加工过程中都要考虑进去，这就需要在进行加工过程中，能够了解并有效地限制这些因素，才能减小加工误差，提高加工精度。参考文献：1 盛精，黄丛林，刘超等. 基于切削温度的切削用量优化的实践与研究J. 中国机械工程，2012(17

23、)：887-88.2 邱宏峰，姜伟军，刘小芳. 机械产品中特殊孔加工的夹具制作J. 职业，2012(24)：90-92.3 姜伟军，邱宏峰. 三爪卡盘夹头钥匙圆柱面横孔加工钻模设计与制作J. 职业，2012(24)：145-146.4 高金华. 一种快速可调式活络压板的设计与应用J. 机械制造与自动化，2012(04)：198-199.5 朱敏红，徐云，王祥鑫. 薄壁套的加工工艺与夹具设计J. 机械制造与自动化，2012(04)：116-117.作者简历： 董金伟（1985年-），男，甘肃省合水县人，助理工程师，2008年7月毕业于东北大学机械工程及自动化专业，现就职于济钢集团有限公司计量质检

24、中心从事机械加工工作。company safety and stability control, management effectiveness, total capacity of 11.37 billion kWh for the year, 104% of the completion of the annual budget, an increase of 111%, when the total electricity 10.4 billion-kilowatt, 104% of the completion of the annual budget, an increase of

25、 112%, complete the exported 3.3217 million tons of coal, completion of the annual budget of 103%, an increase of 163%, with a profit of RMB 908 million, Yet to receive 140 million electricity replenishment and forced spending 40 million cases of the coal Regulation Fund, the company successfully co

26、mpleted the budget value of profit, compared to 07, with all four units of operation, further expansion of coal capacity, company assets profitability has been increased significantly. 4, electricity sales plan exceeded: market-oriented, active marketing efforts, and related units such as State grid

27、 Corporation has established good cooperative relations, external market conditions improved significantly. Purchasing and selling contracts in good condition for the year and seize the Hebei region peak net energy gap of opportunity, making full use of network advantages of directly modulated and H

28、ang Hau station, active power increased and achieved great progress. Total sales for the year of 10.384 billion, when compared with the original purchase and sale contracts increased by 400 million-kilowatt, sales revenue 100% to adjust the budget increase, cumulative hours 5,225 hours, above the So

29、uth Hebei power network average 430 . Culture-building activities, and comprehensively promote the construction pace of creating a culture of XX characteristics, in order to build harmonious XX, enhance the companys cultural soft power has laid a solid foundation. Five, achieved new breakthroughs in

30、 the early, our new development opportunities in 2012, with the first and second phase projects completed and put into use, coal, electricity and one of the advantages of the company show, advanced management concept and good economic and social benefits of the Mountain Community energy be the highl

31、ight of Northern Shaanxi energy base companies, local and national leaders at all levels have come to study visits. On October 29, Hu Jintao, General Secretary of site visit to inspect coal and electricity production during the speech, confirmed the mountain community of coal-electricity integration

32、 business model, further strengthened the confidence in energy development. Meanwhile, at the provincial and municipal levels of Government and the strong support of the parent company, the company approved the work in an orderly fashion in the early phase of the project, has made new breakthroughs,

33、 the company ushered in a brand new development opportunities, the current, three-phase project 4x1000MW project is in accordance with project approval requirements to carry out the preparation work, and strive to 2013 under construction, 2012, 2013, all completed and put into production. XX company would then become the integration project, and Asias largest coal-fired power, coal, electricity and the implementation of integrated