共查询到17条相似文献,搜索用时 171 毫秒
1.
2.
为研究数控机床热变形规律,实现数控机床误差在机实时补偿,进行数控机床主轴热变形理论及试验分析,结果表明,数控机床主轴热变形与主轴温变在距热源约1/3位置存在近似线性关系,即主轴热变形存在伪滞后现象,这一结果为数控机床测温点优化布置及热误差鲁棒建模提供理论依据。为验证机床热变形伪滞后现象,对VM850加工中心主轴热漂移误差在机实时检测并建模,通过自主研发数控机床误差在线实时补偿系统对主轴热漂移误差进行实时补偿,经补偿,机床主轴热漂移误差减少90%以上,有效提高了数控机床主轴精度。 相似文献
3.
4.
针对由几何误差与热误差引起的数控机床工作台与主轴之间相对位置变动的问题,通过试验分析其在不同温度状态下的误差数据,得到机床工作台平面度误差随热变形保持不变的规律,并提出了一种数控机床工作台平面度误差与主轴热误差的综合补偿方法。该方法通过分别建立工作台平面度误差模型和热误差模型,并运用叠加原理建立综合误差补偿模型,对传统固定单位置点建模补偿方法的原理性缺陷进行了改进。结合机床关键部件的实时温度值和刀具位置的实时坐标值,计算出了全工作台各区域各温度阶段的误差补偿值,进而实现了全工作台主轴轴向综合误差的实时补偿。检验及分析结果表明,相比于传统固定单位置点热误差建模补偿方法,该方法所建模型残余标准差减小约7μm,精度提高比例达到50%;单次最大补偿残差减小约11μm,精度提高比例达到60%,大幅度提高了机床的加工精度。 相似文献
5.
6.
杨建国 《世界制造技术与装备市场》2013,(2)
一、引言
影响数控机床加工精度的关键因素中,几何误差和热误差占到总加工误差的70%以上.提高机床的加工精度可以通过设计和制造途径来消除或减少可能的误差源,但是这种靠提高机床制作精度来满足加工精度要求的方法将使得数控机床的成本非常高.本公司研制的智能型数控机床多误差动态实时补偿系统,采用了软件为主并与硬件相结合的系统集成技术,找出数控机床当前各类误差的变化规律,通过误差建模进行多误差的实时预估,并驱动伺服系统实时修正刀具与工件的相对位置,从而抵消了当前成为问题的原始误差. 相似文献
7.
8.
数控机床全误差模型和误差补偿技术的研究 总被引:11,自引:2,他引:11
加工精度是数控机床必须保证的一项性能指标。提高机床精度是先进制造技术的重要课题,有误差避免和误差补偿两种方法。前者使机床造价大幅上升,而且精度的提高也有一定的限度。后者的精度提高几乎没有限制,对数控机床,计算机实时误差补偿技术是一种经济、有效的基本途径。基于多体系统理论,推导了多坐标数控机床,包含几何误差和热误差的全误差模型。文中介绍了坐标数控机床项误差的辨识方法(22线、14线和9线法),还介绍了回转坐标6项误差的辨识方法。通过软件补偿,在3坐标联动和4坐标联动数控机床上实现了几何误差和热误差的补偿。实践结果表明误差模型的准确性和补偿方法的实用性。 相似文献
9.
10.
11.
Jin-Hyeon Lee Jae-Ha Lee Seung-Han Yang 《Journal of Mechanical Science and Technology》2001,15(11):1482-1489
Thermally-induced errors originating from machine tool errors have received significant attention recently because high speed
and precise machining is now the principal trend in manufacturing processes using CNC machine tools. Since the thermal error
model is generally a function of temperature, the thermal error compensation system contains temperature sensors with the
same number of temperature variables. The minimization of the number of variables in the thermal error model can affect the
economical efficiency and the possibility of unexpected sensor fault in a error compensation system. This paper presents a
thermal error model with minimum number of variables using a fuzzy logic strategy. The proposed method using a fuzzy logic
strategy does not require any information about the characteristics of the plant contrary to numerical analysis techniques,
but the developed thermal error model guarantees good prediction performance. The proposed modeling method can also be applied
to any type of CNC machine tool if a combination of the possible input variables is determined because the error model parameters
are only calculated mathematically based on the number of temperature variables. 相似文献
12.
Dr Jenq Shyong Chen Cheng Chang Ling 《The International Journal of Advanced Manufacturing Technology》1996,11(3):198-205
Improving both the positioning accuracy and contouring accuracy of a vertical machining centre has been studied by using a machine tool metrology and in-house error correction techniques. Contouring errors caused by the servo lag and friction of servomechanisms were measured by the circular test and then reduced by off-line parameter tuning of the CNC and servo-driver. The quasistatic thermal errors were predicted online using a neural network based model which was calibrated in advance via a quick set-up and multiple-error measurement system consisting of a spindle-mounted probe and artifacts. Positioning errors caused by both the static geometric errors and thermal effects were eliminated in real-time by a PC based software error compensation scheme integrated with the CNC controller through digital communication. An error reduction of 70% was achieved after error compensation and CNC tuning. 相似文献
13.
Dr Jenq-Shyong Chen 《The International Journal of Advanced Manufacturing Technology》1996,12(4):303-308
This research is concerned with enhancing the accuracy of a machining centre by compensating for thermally induced spindle errors in real-time. A neural network model was developed for on-line thermal error monitoring. A PC-based error compensation scheme was also developed to upgrade a commercial CNC controller for real-time thermal error compensation without any hardware modifications to the machine. The spindle thermal errors of a vertical machining centre were reduced by 70% after compensation. 相似文献
14.
15.
16.
An integrated error compensation method based on on-machine measurement for thin web parts machining
Thin webs are widely used in the aerospace industry for the advantages of compact structure, light weight and high strength-to-weight ratio. Due to its low rigidity, serious machining error may occur, therefore, Finite Element method and mechanism analysis are usually utilized to modeling its deformation. However, they are very time-consuming and only suitable for elastic deformation error. In this study, an integrated error compensation method is proposed based on on-machine measurement (OMM) inspection and error compensation. The OMM inspection is firstly applied to measure the comprehensive machining errors. The Hampel filtering is then used to eliminate outliers, followed by the triangulation-based cubic interpolation as well as a machine learning algorithm which are used to establish the compensation model. At last, the real time compensation of high-density cutting points is realized by developing the compensation system based on External Machine Zero Point Shift (EMZPS) function of machine tool. Three sets of machining experiment of a typical thin web part are conducted to validate the feasibility and efficiency of the proposed method. Experiment results revealed that after compensation, the comprehensive machining errors were controlled under different machining conditions and 58.1%, 68.4% and 62.6% of the machining error ranges were decreased, respectively. This method demonstrates immense potential for further applications in efficiency and accuracy improvement of thin-walled surface parts. 相似文献
17.
Yuxia Lu M. N. Islam 《The International Journal of Advanced Manufacturing Technology》2012,62(9-12):1071-1085
A traditional model for thermally induced volumetric error of a three-axis machine tool requires measurement of 21 geometric error components and their variation data at different temperatures. Collecting these data is difficult and time consuming. This paper describes the development of a new model for calculating thermally induced volumetric error based on the variation of three error components only. The considered error components are the three axial positioning errors of a machine tool. They are modelled as functions of ball-screw nut temperature and travel distance to predict positioning errors when the thermal condition of the machine tool has changed due to continuous usage. It is assumed that the other 18 error components remain identical to the pre-calibrated cold start values. This assumption is justified by the fact that the machine tool’s thermal status significantly affects three axial positioning errors that dominate machining errors for a machine tool after its continuous use. To demonstrate the effectiveness of the proposed model two types of machining jobs, milling and drilling, on a three-axis horizontal CNC machining centre are simulated and the machined part profiles are predicted. The results show that the thermally induced volumetric error was reduced from 115.40 to 45.37?μm for the milled surface, and the maximum distance error between drilled holes for the drilling operation was reduced from 38.69 to ?0.14?μm after compensation. 相似文献