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毕业设计(论文)外文资料翻译系 别： 机电信息系 专 业： 机械设计制造及其自动化班 级： 姓 名： 学 号： 外文出处: Int J Adv Manuf Technol 附 件： 1. 原文； 2. 译文 2013年01月Int J Adv Manuf Technol (2001) 17:649653 2001 Springer-Verlag London LimitedReal-Time Prediction of Workpiece Errors for a CNC Turning Centre, Part 1. Measurement and IdentificationX. LiDepartment of Manufacturing Engineering, City University of Hong Kong, Hong Kong This paper analyses the error sources of the workpiece in bar turning, which mainly derive from the geometric error of machine tools, i.e. the thermally induced error, the error arising from machineworkpiecetool system deflection induced by the cutting forces. A simple and low-cost compact measuring system combining a fine touch sensor and Q-setter of machine tools (FTSFQ) is developed, and applied to measure the work- piece dimensions. An identification method for workpiece errors is also presented. The workpiece errors which are composed of the geometric error, thermal error, and cutting force error can be identified according to the measurement results of each step. The model of the geometric error of a two-axis CNC turning centre is established rapidly based on the measurement results by using an FTSFQ setter and coordinate measuring machine (CMM). Experimental results show that the geometric error can be compensated by modified NC commands in bar turning.Keywords: Dimension measure; Error identification; Geo- metric error; Turning1. Introduction In recent years, ultraprecision machining has made remarkable progress. Some special lathes have been able to make ultra- precision machining, to less than a submicron and nanomicron tolerances a possibility. A common second approach is that the grinding is used to achieve a high level of dimensional accuracy after turning. However, the condition of the cutting tool (diamond) and workpiece (aluminium) have restricted the application of ultraprecision lathes. The second approach increases the number of machine tools and machining processes used 1, which results in an increase in the manufacturing cost. At present, most CNC lathes are equipped with a positioning resolution of 1 urm. Various machining errors in finish turning, however, degrade the accuracy to a level of approximately10 urm, so that when turning carbon steel, a machining error predictably arises in excess of 2030 urm. For improving mach- ining accuracy, the method of careful design and manufacture has been extensively used in some CNC lathes. However, the manufacturing cost based on the above method will rapidly increase when the accuracy requirements of the machine tool system are increased beyond a certain level. For further improv- ing machine accuracy cost-effectively, real-time error prediction and compensation based on sensing, modelling and control techniques have been widely studied 2, so ultraprecision and finish tuning can be performed on one CNC lathe. The positioning resolution of the cutting tools and workpieceis reduced so that it cannot maintain high accuracy during machining because of the cutting-force-induced deflection of the machineworkpiecetool system, and the thermally induced error, etc. In general, a positioning device using a piezo-eletric actuator is used to improve the working accuracy, but the method introduces some problems, such as, the feedback strat- egy, and the accuracy of sensors, which add to the manufactur- ing cost of the products. However, if the workpiece error can be measured by using a measuring instrument, or predicted by using a modelling, the turning program produced by modified NC commands can be executed satisfactorily on a CNC machine tool. Thus, a CNC turning centre can compensate for the normal machining error, i.e. the machine tool can machine a product with a high level of accuracy using modified NC commands, in real time. The workpiece error derives from the error in the relative movement between the cutting tool and the ideal workpiece. For a two-axis turning centre, this relative error varies as the condition of the cutting progresses, e.g. the thermal deflection of the machine tool is time variant, which results in different thermal errors. According to the various characters of the error sources of the workpiece, the workpiece errors can be classified as geometric error, thermally induced error, and cutting-force- induced error. The main affecting factors include the position errors of the components of the machine tool and the angular errors of the machine structure, i.e. the geometric error. The thermally induced errors of the machine tool (i.e. the thermal error), and the deflection of the machining system (including the machine tools, workpiece, and cutting tools) arising from cutting forces, are called the cutting-force error. This paper analyses the workpiece error sources in turning. The errors of a machined workpiece are mainly composed of the geometric error of the machine tools, the thermally induced error, and the error arising from machineworkpiecetool sys- tem deflection induced by the cutting forces. A simple and low-cost measuring instrument for the workpiece dimensions, which combines a fine touch sensor and machine tool Q-setter (FTSFQ), is described, and applied to measure the workpiece error. A new method for identifying the geometric error, the thermal error, and the cutting-force error is also presented for a two-axis turning centre. Finally, the modelling of the geo- metric error of a CNC turning centre is presented, based on the measurement results using the FTSFQ and CMM. The geometric error can be compensated by the modified NC command method.2. Error Sources in Turning The machine tool system is composed of the drive servo, the machine tool structure, the workpiece and the cutting process. The major error sources derive from the machine tool (thermal errors, geometric errors, and forced vibrations), the control (drive servo dynamics and programming errors) and the cutting process (machine tool and cutting tool deflection, workpiece deflection, tool wear, and chatter) 3. Errors derived from the machine tool include thermal errors(machine thermal error and workpiece thermal errors), geo- metric errors, and forced vibrations, which dominate machining accuracy. The thermal errors and geometric errors are the dominant factors with respect to machining accuracy in fine cutting. However, machine tool errors can be decoupled from the other error sources and compensated 4. The error derived from forced vibration can be reduced through balanced dynamic components and vibration isolation 3. The errors derived from the controller/drive dynamics are related to the cutting force disturbances and the inertia of the drive and the machine table. These errors can be reduced by an interpolator with a deceleration function 5 or by an advanced feed drive controller 6, these errors, reduced by using the above methods, are small when compared with other error sources. Owing to the demand for high productivity, high feedratesand large depths of cut are required, which result in large cutting forces. Therefore, the cutting-force induced deflections of the machine tool (spindle), tool holder, workpiece, and cutting tool make significant contributions to machining accu- racy during the cutting process. In addition, tool wear and machine tool chatter are also important error sources in the cutting process. However, these effects are neglected here so as to focus on the main error sources. In short, the error of a machined workpiece, i.e. the totalmachining error (iTot), is composed mainly of the geometric errors of the machine tool(s) (iG), the thermally induced error (iT), and the error (iF) arising from the deflection of the machineworkpiecetool system induced by the cutting forces. Hence, iTot iG + iT + iF(1) In the next section, we present a novel compact measuring instrument and a new analytical approach for measuring and identifying workpiece errors in turning.3. A Compact Measurement System Contact sensors, such as touch trigger probes, have been used to measure workpiece dimensions in machining. In machining practice, the measuring instrument is attached to one of the machines axes to measure a surface on the workpiece. A TP7M or MP3 associated with the PH10M range of motorised probe heads or a PH6M fixed head have been used widely in the automated CNC inspection environment owing to their high level of reliability and accuracy and integral autojoint. Though the probeheads are of adequate accuracy (unidirectional repeatability at stylus tip (high sensitivity): 0.25 urm; pre-travel variation 360 (high sensitivity): 0.25 urm), and versatile in application, they have clear drawbacks, including complexity of construction, high price ($4988), and the need for careful maintenance. To overcome these drawbacks of touch trigger probes,Ostafiev et al. 7 presented a novel technique of contact probing for designing a fine touch sensor. The cutting tool itself is used as a contact probe. The sensor is capable of yielding measurement accuracy comparable to that of the best touch trigger probe in use. Moreover, the principle of operation and construction of the sensor is extremely simple, the cost of the sensor is low, and the maintenance is very easy. In this paper, this sensor will be used to measure the diameter of a workpiece associated with the Q-setter. A touch sensor is mounted on a CNC turning centre. When we manually bring the tool nose into contact with it, an interrupt signal is generated for the NC unit to stop an axis. Moreover, it can write in an offset and a workpiece coordinate shift automatically. This function facilitates set-up when replac- ing a tool, and this convenient function is called the “Quick Tool Setter” or “Q-setter”. Based on the above principle, we can operate a switch, which is controlled by fine touch sensor, between the Q-setter and NC unit. When the tool tip touches the workpiece surface, the fine touch sensor can send a control signal to the switch, to turn it to the “off” state. See Fig. 1, the fine touch sensor replaces the Q-setter function, to stop an axis and write in an offset and a workpiece coordinate shift automatically. Therefore, the fine touch sensor associated withFig. 1. Flow diagram of a fine touch sensor fixed on a CNC controllera Q-setter (FTSFQ) can be used to inspect the diameter of the workpiece, the method is shown in Fig. 2. When the cutting tool tip touches the workpiece surface, a “beep” sound is heard and the switching “OFF” signal appears and the axis stops automatically, as far the Q-setter. A new “tool offset” XT-W is obtained by the NC unit (display of CNC). Before touching the workpiece surface, the cutting tool tip touches the Q-setter, and the “tool offset” XT-Q is obtained. Thus, the on-machine workpiece diameter Don-machine is given by the following Eq.:Don-machine = 2 H + XT-Q - XT-W (2)whereXT-Q is the tool offset when the cutting tool contacts the Q-setterXT-W is the “tool offset” when the cutting tool contacts the workpiece surfaceH is the distance from the centre of the Q-setter to the centre of the spindle in the x-axis direction and is provided by the machine tool manufacturer, for the Seiki-Seicos L II Turning centre, it is 85.356 mm. Ostafiev and Venuvinod 8 tested the measurement accuracyof the fine touch sensor, performing on-machine inspection of turned parts, and found that the method was capable of achiev- ing a measurement accuracy of the order of 0.01 urm under shop floor conditions. However, the measurement accuracy of the fine touch sensor together with the Q-setter obtained an accuracy of about urm because the results of the measurement system are displayed by the CNC system, and the readings accuracy of the CNC system is up to 1 urm.4. Identification of Workpiece Errors From the above analysis of error sources of the workpiece, the total error iTot of machined parts is mainly composed of the following errors in a turning operation:. iG the geometric errors of machine tools. iT the thermally induced error.Fig. 2. Inspection for the diameter of a workpiece by using the fine touch sensor with the Q-setter of a machine tool. iF the cutting force induced error.To analyse the error sources of a machined workpiece, Liu & Venuvinod 9 used Fig. 3 to illustrate the relationship amongst dimensions associated with different error components in turning. In Fig. 3, Ddes is the desired dimension of the workpiece; Domw is the dimension obtained by on-machine measurement using FTSFQ immediately after the machining operation; Domc is the dimension obtained by on-machine measurement usingFTSFQ after the machine has cooled down; and Dpp is the dimension obtained by post-process process measurement using a CMM after the workpiece has been removed from the machine. When the workpiece has been machined, and removed from the machine tool system, it is then sent for inspection of the dimensions using a CMM. This procedure is called post-process inspection, by which we obtain it Dpp value. As the positioning error of the CMM is very much smaller than the desired measurement accuracy, the total error isiTot = (Dpp - Ddes)/2 (3) The dimension Domw is obtained through on-machinemeasurement using FTSFQ immediately after machining, i.e.the machine is still in the same thermal state as at the time of machining. The measurement is made with the same positioning error as that which existed during machining. Hence, the positioning error in this state would be equal to (iG + iT), i.e.(Dpp - Domw)/2 = iG + iT(4) When the machine has completely cooled down, i.e. withoutthermal error, the dimension Domc can be obtained by on- machine measurement using FTSFQ. The measurement has a positioning error equal to the geometric error of the machine at the location of measurement. Hence, the positioning error in this state would be equal to (iG), i.e.(Dpp - Domc)/2 = iG(5) Combining Eqs (4) and (5), the thermally induced error iT is (Domc - Domw)/2 = iT(6) Hence, taking Eqs (1), (3), and (4) into account, the cutting-force-induced error owning to the deflection of the machineworkpiecetool system iF is(Domw - Ddes)/2 = iF(7)Fig. 3. The relationships among dimensions. So far, the machining error is composed of the geometric error, the thermal error, and the cutting-force-induced error and can be identified using the above procedure. The thermal error and the force-induced error modellings is addressed in Li 10. Here, the geometric error of machine tool is measured and modelled.5. Modelling of Geometric Error The geometric error of a workpiece is mainly affected by the offset of the spindle, and the linear error and the angular errors of the cross-slide for a two-axis CNC turning centre. Here, only the geometric error of workpiece in the x-axis direction is taken into account for a bar workpiece. This is expressed by the following formula.iG = i(s) - (x) hT-Q - ix(x)(8)wherei(s) is the spindle offset along the x-axis direction(x) is the angular error (yaw) of the cross-slide in the x, y-planeix(x) is the linear displacement error of the cross- slide along the x-axis direction The spindle offset is a constant value independent of the the machining position. The angular error term and the linear error term are functions of the cross-slide position x. In this paper, the FTSFQ is mounted on a Hitachi Seiiki, HITEC-TURN 20SII two-axis turning centre. The FTSFQ cali- bration instrument was developed to measure rapidly the dimen- sion of the workpiece in the x-axis direction on the two-axis CNC turning centre when the machine has completely cooled down, i.e. without the effect of thermal error. The geometric error can be computed by using Eq. (5) according to the measured results. First, the diameter of a precision ground test bar is measured at 10 positions, 20 mm apart, by a CMM, their values Dppi (i = 1, 2, . . ., 10) are recorded. Then, the test bar is mounted on the spindle, and its diameter is also measured at 10 positions, 20 mm apart, by the FTSFQ. The measurement arrangement is shown in Fig. 4, the readings are Domcl (i = 1, 2, . . ., 10). Thus, the geometric error at each point along the x-axis for the bar workpiece are computed as follows:iGi = (Dppi - DGi)/2 (9) From starting point B to point A, the results are shown in Fig. 5 for diameters of 30, 45, 60, and 75 mm. The workpieceFig. 4. Diagram of the geometric error measurement of the workpiece using FTSFQ.Fig. 5. Geometric errors of the workpiece along the z-axis.geometric errors in the z-axis direction are the same. The workpiece geometric errors, however, increase along the x-axis direction, as shown in Fig. 6. These average geometric errors are 7.1036, 9.0636, 10.7764, 12.5955 (urm) for dia- meters 30, 45, 60, and 75 mm, respectively. Hence, the geo- metric errors of the two-axis CNC turning centre can be calculated by the following Eq.:iG(x) = -0.121x - 3.519 (10)where x is the diameter of the workpiece (mm), iG(x) (urm)is the geometric error of the workpiece.6. Compensation of Geometric Error To compensate for the geometric error in the direction of the depth of cut, the tool path can be shifted in accordance with the error. The NC commands in turning are modified, at a minimum resolution 1 urm, in the direction of the depth of cut. The calculated geometric error exceeded 1 urm according to the equation (10), as illustrated in Fig 7. Figure 8 shows that the workpiece errors include the geo- metric error, the thermal error and the cutting force error. The tool path determined by the calculated geometric error, and the workpiece error are compensated for by the modified NC command method. In this example, we used a cutting speed of 4 m s1, a feedrate of 0.2 mm rev1, a depth of cut ofFig. 6. The average geometric error for the different diametersFig. 7. Compensation of geometric error.Fig. 8. Compensation of geometric error by a modified NC command.1 mm (cutting length 100 mm), a diameter of 40 mm, mild steel workpieces, and DNMG 1506 04 QM tools. The work- piece error was measured using our FTSFQ at 10 positions10 mm apart. The workpiece errors were reduced by means ofthe compensation of the geometric error. The remaining work- piece error contains the thermal error and cutting force error, these will be discussed in part 2 10 and part 4 11. Experi- mental results suggest that the geometric error in finish turning can be compensated for by the use of this simple method described above.7. Conclusions Owing to increasing demand for higher precision coupled with lower costs in the machining industry, there is a growing need for automated techniques leading to enhanced machiningaccuracy. In this paper, the workpiece error sources are ana- lysed for a two-axis CNC turning centre, which derive mainly from the geometric error of the machine tool, the thermally induced error, and the error arising from MFWT system deflec- tion induced by the cutting forces. A simple and low-cost measuring system combining a fine touch sensor and Q-setter for machine tools (FTSFQ) is developed to measure the work- piece error on-machine. The workpiece errors can be divided into the geometric error, the thermal error, and the cutting force error from the on-machine and post-process measured results. The geometric error function of a two-axis CNC turning centre can be established rapidly from the measurements by using the FTSFQ and a CMM. Experimental results show the geometric error can be compensated for by the modifying the NC commands in finish turning.References1. T. Asao, Y. Mizugaki and M. Sakamoto, “Precision turning by means of a simplified predictive function of machining error”, Annals CIRP, 41(1), pp. 447451, 1992.2. Jingxia Yuan and Jun Ni, “The real-time error compensation technique for CNC machining systems”, Mechatronics, 8(4), pp.359380, 1998.3. Sung-Gwang Chen, A. Galip Ulsoy and Yoram Koren, “Error source diagnostic using a turning process simulator”, Transactions ASME Journal of Manufacturing Science and Engineering, 120, pp. 409416, 1998.4. V. S. B. Kiridena and P. M. Ferreira, “Modeling and estimation of quasistatic machine-tool error”, Transactions NAMRI/SME, pp.211221, 1991.5. Y. Koren, Computer Control of Manufacturing Systems, McGraw- Hill, 1983.6. Y. Koren and C. C. Lo, “Advanced controllers for feed drives”,Annals CIRP, 41(2), pp. 689698, 1992.7. V. Ostafiev, I. Masol and G. Timchik, “Multiparameters intelligent monitoring system for turning”, Proceedings of SME International Conference, Las Vegas, Nevada, pp. 296300, 1991.8. V. A. Ostafiev and Patri K. Venuvinod, “A new electromagnetic contact sensing technique for enhancing machining accuracy”. IMECE-97, ASME, 1997.9. Z. Q. Liu and Patri K. Venuvinod, “Error compensation in CNC turning solely from dimensional measurements of previously machined parts”, Annals CIRP, 48(1), pp. 429432, 1999.10. X. Li, “Real-time Prediction of workpiece errors for a CNCturning centre. Part 2. Modelling and estimation of thermally induced errors”, International Journal of Advanced ManufacturingTechnology, 2000.11. X. Li, “Real-time prediction of workpiece errors for a CNC turning centre. Part 4. Cutting-force-induced errors”, InternationalJournal of Advanced Manufacturing Technology, 2000. 期刊或杂志名：Int J Adv Manuf Technol出版社：Springer-Verlag London Limited出版时间：2001数控车削中心工件误差实时预报第1部分：测量和鉴定李小俚 制造工程系，香港城市大学，香港本文分析了工件在加工旋转时的误差来源，其中主要来自机加工工具的几何误差，即热误差，该误差产生于机加工工件的切削力引起的刀具系统的偏转。一个简单和低成本的紧凑型测量系统相结合的灵敏的触摸传感器的工具（FTS-Q）产生了，并应用于测量工件表面.并且还介绍了一种识别工件误差的方法。工件的误差是由几何误差，热误差组成的，而切屑力误差根据每一步的测量结果是可以确定的。几何误差由建立在快速的基础上的两轴CNC车削中心模型测量，测量结果由坐标测量机（CMM）用FTS-Q的方法显示出来。实验结果表明，在工具旋转时，通过修改数控指令，这种几何误差可以得到补偿。关键词：尺寸测量;错误辨识;几何误差;旋转1. 导言近年来，超精密加工已取得了显著进展，一些特殊的车床已能作出超一般的机械加工，实现了不到1微米，甚至有实现超微米的可能性。而实现这种可能公用的一种方法是在开机后用高水平的三维来实现磨削的准确性。然而，有些切削工具（如钻石）和一些工件（如铝）应限制应用超精密车床。第二种实现的方法是增加机床数目的加工工艺，但是这将导致制造成本的增加。 目前，我国大部分CNC车床配备定位达到了1微米。然而，在完成车削时，各种加工误差的准确性应以某种程度的降低约10微米，所以，当谈到碳钢时，加工误差可以预见超出20-30微米。为提高加工的准确性，这种精心设计的方法和制造已被广泛应用于一些CNC车床。然而按以上方法制造精度要求系统超出一般水平的机床时，生产的成本将会迅速的增加。为了进一步改善提高机床精度的效益成本，实时的误差预报以及基于传感的补偿建模与控制技术已得到了广泛的研究，因此，超精密的加工校正，可以安排在一般的CNC车床。定位解决了刀具和工件的切削，但它不能保证高度的准确性，因为在加工中，切削力会影响机床-工件-刀具系统，并且热也会导致误差等。一般来说，定位装置采用压电激励器，用于改善工作的准确性，但是，采用这种方法也带来了一些问题，例如反馈系统和精度传感器，这些都会增加制造产品的成本。但是如果工件的误差可以用测量仪器测量，或者利用模型可以提前预知，再执行已经做好的修饰数控命令，那么将会充分利用好数控机床。因此，在一定时间内，这种数控车削中心可以补偿一般的加工误差，即这种机床采用可改性数控命令能制造出具有高水平精确度的产品。工件的误差来自刀具和工件的实际相对运动与理想相对运动的误差。如果是双轴车削中心，由于车削条件不同，导致相对误差各不相同，如机床刀具的时变产生热偏转，导致不同的热误差。根据工件各种不同误差来源，工件误差可分为几何误差，热误差，以及切削疲惫误差。主要影响因素包括：组成机床部分的位置错误和机械结构的角错误，即几何误差。这种由于切削力产生的机床热误差（即热误差），和影响的加工系统（包括机床，工件和刀具），被称为切力误差。本文分析了工件在加工旋转时误差的来源：数控机床的几何误差，热误差，切削力产生的机械工件和刀具系统的偏离误差。一个简单而低成本的测量仪器，它具有良好的触摸传感器和机床的FTSF-Q装置，能描述工件的尺寸，并用于测量工件的误差。已经有一种新的方法来确定几何误差，热误差，并且能够回馈切力误差到两轴车削中心。最后，数控车削中心的造型几何误差由FTSF-Q和CMM来测定。这种几何误差可以由改进的数控指挥得到补偿。2.车削加工中的误差来源机床系统是由驱动伺服，机床结构，工件和切削过程组成。主要误差源来自机床（热误差，几何误差，和强迫振动） ，控制（伺服驱动器动力学及编程错误） ，以及切割进程（机床及刀具偏转，工件偏转，刀具磨损和颤振）。其中对加工的准确性占主导地位的误差来自机床，包括热误差（机床热误差和工件的热误差），几何误差和强迫振动。在加工精细工件时热误差和几何误差是主要的影响因素。然而，机床误差不同与其他误差来源，它可以得到补偿。均衡动态部件以及隔离振动可以减少由误差衍生来的强迫振动。 控制器和驱动器的误差来自切削力的干扰和机座的惯性，这些误差可能减少一个接一个减速器的功能，或者一个先进的伺服驱动控制器，这些误差，相对于其他误差来源，利用上述方法可以在他们较小时得到减少。由于需求大，生产率高， 等级要求自由和大深度的削减要求，而导致产生较大切削力。因此，割力诱导挠度来自机床（主轴） ，刀柄，工件，并且刀具在加工精度切削过程起了重要作用。此外，在切削过程，刀具磨损和机床颤振，亦是重要的误差来源。不过，这些影响可以忽略，所以在这里把焦点放在主要误差来源。总之，加工一个工件的误差，即总加工误差()，主要由机床几何误差(), 热误差(),以及由切削力所产生的机床-工件-刀具系统的挠度诱导误差()组成，故： + + (1) 在下一节中，我们提出一个新的紧凑型测量仪器和新的分析方法来衡量和确定工件的旋转误差。3 .紧凑型测量系统接触传感器，例如触摸触发探针，已用于测量工件尺寸加工。在加工实践中，测量仪器是附在机器其中的轴，以衡量一个工件的表面。一种tp7m或是MP3与ph10m各种机动探头元件或ph6m固定头由于其高的可靠性和准确性以及完整的加工点，广泛应用于自动化数控视察环境。虽然该探头有足够的精确度（针式特有的单项重复性（高灵敏度）：0.25微米;提前可设定的旋转360 （高灵敏度）：0.25微米），并且可进行多种功能，他们也有明显的缺点，例如制造的复杂性，高价格（4988美元），以及复杂的维修。 为了克服这些缺点，Ostafiev等人介绍了一种技术并以此设计了一个良好的触摸传感器：触摸触发探头，该传感器刀具本身就作为探针。该传感器的测量精度是当年触摸触发探头最好的。此外练习使用这种传感器是非常简单的，制造成本很低，而且维修保养是非常容易的。在本文中这个传感器将作为Q装置来测量工件直径等一些相关的问题。 触摸感应器应安装在一个数控车削中心上。作为数控单元，当我们手动把刀尖触碰到主轴时，它会产生中断信号。此外，它可以记录一个工件自动转向的坐标。这种功能方便随时更换刀具。因此，拥有这种功能称为“快速换刀装置”或“Q装置”。基于上述原则，我们可以设计一个由良好的触摸传感器构成的开关，控制Q装置和NC单元。当刀尖触及工件表面，精细式触摸传感器能发出一个控制信号转换，使之向关闭状态。见图1。优良式触摸传感器取代了问答式的Q装置功能，以防止轴在记录的工件坐标间偏移。 图1 触摸传感器固定在一个CNC控制器的流程图因此，优良的触摸传感器如图1，流程图的数据由触摸传感器即固定的Q装置(FTSFQ) 测得，可以用来检查工件直径，该方法是图2.当刀具尖端触及工件表面时，将发出“哔哔”的声音，这是开关的 “关”的信号，主轴将根据Q装置自动停止。一个新的“刀具补偿”将由NC单元提供（展示数控）。在触及工件表面前，刀具尖端触及Q装置以及“刀具补偿”就已经获得。因此，对于工件直径有下列关系： =2H + (2)其中： ：刀具切削时Q装置提供的刀具补偿；：刀具触及工件表面时的刀具补偿； H是Q装置在X轴方向上离主轴的距离。这由机床制造商提供，如Seiki-Seicos L II旋转中心，它是85.356毫米。Ostafiev和Venuvinod两款触摸传感器在测试测量精度时，在演示机上能够测量精度在0.01微米以下的精度条件。然而，优良的触摸传感器在测量精度时获得的精度为微米，因为测量结果在系统中显示出来时，数控系统和读数精度系统最大是1微米。4. 确定工件的错误上述分析中工件的误差源的总误差主要由以下在加工零件车削操作中的误差组成：的机床的几何误差。：热引起的错误。：切削力引起误差。图2 使用Q-setter的机床利用优良的触摸传感器对工件的直径进行检查 要分析一个加工工件的误差源，刘Venuvinod 。图3用来说明在车削时不同的误差分量之间的尺寸关系。 另外，在图3中，是所希望的工件尺寸; 是在测量使用FTSFQ加工操作后立即获得的维度; 是在机床FTSFQ加工操作后冷却下来测量获得的尺寸，使用三坐标测量机测量已经从机器上取下的工件通过处理后获得的尺寸。 当工件被加工时，机床系统中使用CMM的尺寸进行检查。此过程被称为后工序检验，由于CMM的定位误差比所需的测量精度更小，总误差是：= (-)/2 (3)通过以上获得的尺寸，使用FTSFQ测量后立即加工，即机器在加工时仍然在相同的热状态。测量时，在加工过程中具有相同的定位误差。因此，在该状态下的定位误差将等于( +)，i.e.()/2 =+ (4)当机器完全冷却下来，即无热误差时，尺寸可以通过FTSFQ测量。测量等于测量的位置处机器具有的几何误差的定位误差。因此，在该状态下的定位误差将是（），即等于 ()/2= (5) 结合式（4）和（5），热诱导的错误，它是 ()/2 = (6) 故，以式（1），（3）和（4）考虑到，如果是机器的工件的刀具系统偏转切割力引起的误差，是： (-)/2= (7) 图3 维之间的关系 到目前为止，由加工误差的几何误差，热误差和切割力引起的误差，可以使用上述步骤来识别。这里，机床的几何误差的测量和模拟解决热误差和力引起的错误构模。5.模型的几何误差 两轴CNC车削中心滑动、主轴偏移的工件的几何误差主要由线性误差和角度误差交叉的影响。这里，仅在x轴方向上的工件的几何误差是由以下结构式表示：=(x) (8)其中： ：十字滑块在x，y平面沿x轴方向(x)的偏移量是主轴的转角误差； ：十字滑块沿x轴方向的线性位移误差； 独立的加工位置主轴偏移量是一个恒定值，转角误差项和线性误差项是十字滑块的位置x的函数。 在本文中，国际展贸中心将FTSFQ安装在日立Seiiki开发的FTSFQ校准仪器上，用来进行20SII两轴车削加工中心快速测量工件中的x轴方向上的两轴CNC车削中心，当该装置已经完全冷却下来的维数，即没有热误差的效果。可以通过使用公