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Shang-Liang Chen Tsann-Huei Chang Yi-Chin Lin 《The International Journal of Advanced Manufacturing Technology》2006,30(7-8):778-788
The design of using a parallel kinematic mechanism as a structure of machine tools has several good points compared with the traditional machine tools. However, the problem of singularity is usually encountered during real applications. Therefore, singularity analysis is very essential for using a parallel kinematic mechanism in real machining applications. Screw theory based on the Plücker coordinate system is one of the effective methods for analyzing the singularity of a parallel kinematic mechanism. A TRR–XY five DOF parallel kinematic machine tool that was developed in this research is adopted as an example for investigating the feasibility of this method. A 6×6 matrix calculation is usually required in screw theory for analyzing a six DOF mechanism. For a three DOF mechanism, the analysis using the screw theory becomes more complicated. An equivalent component method is addressed in this research to simplify the singularity analysis for a three DOF mechanism. The effects of differently designed dimensions of machine tools on the singularity are also investigated in this research. 相似文献
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新型3T2R龙门式混联机床动力学模型 总被引:2,自引:0,他引:2
提出了一种以能实现沿X、Z轴平移和绕X、Y轴转动的新型并联机构2-RPU2-UPS作为主体,辅以能实现主体Y轴滑动的直线导轨来共同实现五坐标联动加工的一种新型龙门式混联机床的机构设计方案。运用螺旋理论分析了该机床实现3T2R运动原理,计算出该机床的自由度,进行输入选取与论证,并进行机床机构奇异分析,提出减少奇异的参数设计条件。建立该机床的位置反解数学模型,推导出了该机床的速度雅可比矩阵和加速度分析表达式,求解了该机床的位置反解、速度和加速度。基于虚功原理和该机床的运动学模型建立该机床的动力学模型,并采用Adams软件对该机床动力学进行模拟仿真,模拟结果表明理论结果完全正确。 相似文献
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自动化加工设备的刀具分组分配方法 总被引:1,自引:0,他引:1
在自动化加工系统中,根据零件的加工工艺过程要求和作业计划给各个加工设备分配刀具是刀具管理的重要内容.提出一种基于经验和知识判断算法的启发式刀具分组分配算法.该方法将加工系统所要加工的零件和所要使用的刀具同时进行分组,对每组零件配备一组刀具,从而减少了加工系统的刀具库存量和配送、安装、调整次数. 相似文献
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Julie Z. Zhang Joseph C. Chen 《The International Journal of Advanced Manufacturing Technology》2008,39(1-2):118-128
Machine condition plays an important role in machining performance. A machine condition monitoring system will provide significant economic benefits when applied to machine tools and machining processes. Development of such a system requires reliable machining data that can reflect machining processes. This study demonstrates a tool condition monitoring approach in an end-milling operation based on the vibration signal collected through a low-cost, microcontroller-based data acquisition system. A data acquisition system has been built through interfacing a microcontroller with a signal transducer for collecting cutting vibration. The examination tests of this developed system have been carried out on a CNC milling machine. Experimental studies and data analysis have been performed to validate the proposed system. The onsite tests show the developed system can perform properly as proposed. 相似文献
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S.-L. Chen Y.-C. Liu 《The International Journal of Advanced Manufacturing Technology》2001,18(4):254-265
A coordinate system with multiple non-orthogonal axes, defined for a parallel-link machine tool is very different from that
for a conventional serial-type machine. Therefore, a special post-processor that can automatically transfer the cutter location
data (CL-data) into machine specific NC commands is essential for real machining applications of a parallel-link machine tool.
Parallel-link machine tools have been investigated by many previous workers. However, work on the theory of post-processors
for this machine tool is very sparse, and most is focused on the orthogonal serial motion. The potential benefits of the parallel-link
machine tools make work necessary and urgent on the transformation of the CL-data from a CAD/CAM system into NC commands for
special parallel-link machine tools. A six degrees-of-freedom (DOF) parallel-link machine tool constructed as a 6-3-3 mechanism
was selected in this work to investigate the theory of post-processing, and the effects of the cutter shapes and the machine
construction on it. The parametric representations of different cutter shapes defined by the DIN standard were adopted in
the work, increasing the usefulness of the post-processor theory developed. Specific parameters must be modified in the post-processor
for different tools applied for real cutting. The tilt angle and yaw angle of the cutter, relative to the normal direction
of the cutting surface, is also included in the theory. Finally, the NC code is generated using LabVIEW software, and simulations
were performed to investigate the correctness based on several designed tool paths. 相似文献
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采用CAD变量几何法,用两种新型5自由度3SPS+RRPU和2SPS+RRPRR并联机床对任意3D自由曲面进行法向加工。通过CAD几何约束和尺寸驱动技术,首先建立两种并联机床的模拟机构,再在并联机构动平台上构造任意3D自由曲面和刀具轨迹的引导平面,与并联机构合成,得到模拟并联机床。保持刀具与自由曲面垂直关系,给定加工路径,各驱动杆长和动平台的位置能自动求解和动态显示。结果表明:CAD变量几何法不仅简单直观,而且省去了大量的编程计算。 相似文献
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Yongjun Hu Jun Wan Lei Yuan Tian Zhang Jingnan Cao Feng Li Xiaoling Cheng Xiaohua Jie Haiyan Zhang 《The International Journal of Advanced Manufacturing Technology》2018,95(5-8):1607-1615
Tool path generation is one of the key challenges in multi-axis sculptured surface machining. Besides geometry accuracy, machining processes have been considered in tool path generation in order to improve machining quality and efficiency as far as possible. However, so far, the machine tool accuracies have not been yet fully taken into account during tool path generation. Contour accuracy is one of the most important precision indexes to guarantee the machining quality of sculptured surfaces. One of the major reasons causing contour error is the dynamic mismatch between feed axes of machine tools. In this study, the mathematic relationship between the cutting direction, dynamic mismatch of feed axes and contour error is theoretically established. The mathematic relationship can be used to calculate the optimal cutting directions which minimize the contour error caused by dynamic mismatch between feed axes during machining a sculptured surface by a three-axis machine tool. A machining experiment is carried out to verify the mathematic relationship. In the experiment, the tool paths are generated along the optimal cutting direction and other cutting directions for comparison. The results show that the contour error under the case of the optimal cutting direction is much smaller than that under the other cases. 相似文献
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三杆混联数控机床的运动学研究 总被引:4,自引:0,他引:4
介绍了一种3-TPS(RRR)型混联机床,该机床既可进行立式加工,将工作头旋转一定角度后又可实现卧式加工。在工作头下面安装一个数控转台,并配置自动换刀系统后,机床可进化为一台五轴联动的数控加工中心。在分析其约束机构的基础上,给出了机构的位置、速度、加速度逆解方程及雅可比矩阵的计算公式,并进行了机床的工作空间分析。理论分析表明,3-TPS(RRR)型混联机床运动学方程形式简洁,计算简单,控制计算方便,在运动空间内无运动干涉和耦合,无奇异点和不定形位,可操作性良好,有效工作空间大。 相似文献
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研究和验证了BJ-04-2(A)型并联机床的加工精度与加工表面粗糙度。研究手段是选择国家标准样件进行加工实验,样件加工采用一次装夹,运用端面铣削、侧刃铣削、钻削和镗削的方法加工而成。实验数据结果的分析表明,BJ-04-02(A)型并联机床加工精度中,直线度基本满足国家标准的要求,其它精度指标则未达到标准的要求,加工的表面粗糙度相当令人满意。 相似文献
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Sylvain Pateloup Hélène Chanal Emmanuel Duc 《The International Journal of Advanced Manufacturing Technology》2013,69(5-8):1233-1248
The definition of machining processes with respect to complex kinematic machine tool behaviour involves the control of machine accuracy and kinematic performances. The aim is to propose process settings and tool paths which guarantee the required machining quality while maximizing productivity. This article presents an experimental protocol which enables the determination of machine tool structure behaviours which have an influence on machining quality. In parallel, an experimental analysis of the different kinds of settings which can improve machining quality is carried out. Two kinds of settings appear: the first class of settings improves machining quality or machining time, and the second class has an antagonistic influence on machining quality and machining time. Thus, the definition of the second class of settings arises from an optimisation between first-order defects, second-order defects and machining time. The developed method is illustrated on a parallel kinematic machine tool, the Tripteor X7. Note that this study is a first step towards controlling machine tool behaviour during machining. 相似文献
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王维 《机械设计与制造工程》2011,(7):23-24,27
对零件中曲面的数控加工方法进行了阐述,提出利用3轴2联动数控铣床加工曲面的可行性,结合UG软件说明自动编程的方法和注意事项,最后以实例说明了具体方法和步骤,证明了利用3轴2联动数控铣床加工曲面的可行性。 相似文献
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目前数控机床碰撞检测通常利用系统的仿真功能对加工G代码进行检测,仅考虑数控机床加工过程中加工轨迹上刀具与理想状况下的工作台、夹具之间是否有干涉现象,难以满足开放式重型数控机床动态的加工环境、装夹方式以及刀具尺寸变化等实际情况。将数字孪生引入重型数控机床碰撞检测,构建了感知-演化预测-反馈的碰撞检测框架,即通过构建数控机床的数字孪生体,动态感知工件、夹具、刀具等加工要素,并感知数据驱动孪生模型演化,从而预测数控机床加工过程中潜在的干涉现象,提高了机床加工效率,避免加工过程的潜在危害。将所提方法应用于重型数控龙门镗铣机床ZK5520的碰撞检测,证明了其有效性与可行性。 相似文献
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M. Shiraishi 《Precision Engineering》1989,11(1)
In-process techniques for cutting processes and machine tools are surveyed through representative examples. Detection of cutting force and chatter vibration are especially important in cutting processes. As for machine tools, four measuring items will be important which include the driving system, the bearing and rotating systems, the temperature control system, and the monitoring system. They are the primary factors to be taken into consideration for achieving high machining accuracy. 相似文献
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点接触曲线圆柱齿轮是一种新型平行轴传动齿轮,用常规的机床和刀具难以完成其齿形的高效加工.利用六轴数控铣齿机和面铣式刀盘完成该齿轮的模拟加工.首先,根据该齿轮的成型原理,推导齿面的数学模型,求解齿面点云数据,基于点云数据在三维建模软件中构建齿轮实体模型;然后,在VERICUT中构建数控铣齿机和刀具,再编写齿轮加工的数控程... 相似文献