共查询到19条相似文献,搜索用时 250 毫秒
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本文通过考察外圆磨削循环中工件每转实际磨削深度变化规律与砂轮锋利度的密切关系,提出用神经网络ART2模型对磨削过程中工件每转实际磨削深度变化规律进行数据处理,可以实现在线识别磨削过程砂轮的锋利度。针对磨削加工的特点,提出新的ART2模型匹配度判据。设计制作了相应的数据采集处理系统,对实际磨削过程不同工艺参数的情况下砂轮锋利度进行识别,证实了这种新的识别砂轮锋利度模型及监测系统是十分有效的。 相似文献
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使用砂带磨削装置磨抛工件外圆表面是一种简便、易行且有效的方法。当采用弹性表面接触轮时,吃刀深度与实际磨削深度相差较大,吃刀起始点不易确定,给磨削精度的控制造成困难。一、砂带纵向外圆磨削机理由于存在沿砂轮宽度方向上的工件运动,所以纵向外圆磨削不同于切入式外圆磨削,它有自己的磨削机理。图1中f为工件每转纵进给量。对于砂轮磨削,在砂轮使用的初期阶段,第1段大约磨去总余量的80%,第二段磨去余量的10%,而第4段以 相似文献
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采用CBN砂轮,在砂轮线速度为90~210m/s的磨削条件下,对45钢进行了高效深磨实验.分析了不同工况对磨削力的影响.实验表明,在高效深磨过程中,提高砂轮线速度使磨削力减小,工件表面粗糙度值下降;增加磨削深度使磨削力上升、比磨削能下降、提高磨削效率,也能保证工件表面质量. 相似文献
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快速点磨削周边磨削层模型及参数 总被引:3,自引:1,他引:2
为深入研究快速点磨削机理及工艺,根据快速点磨削的技术与几何学特征,建立点磨削周边接触层及参数的数学模型,对砂轮和工件的等效速度和直径、磨削参数进行理论分析。在已建立快速点磨削接触层及参数的理论模型基础上,推证计及点磨削变量角度和磨削深度的砂轮周边理论接触宽度的计算公式,并对超薄快速点磨 削砂轮周边理论接触宽度和表面粗糙度进行数值仿真。结果表明:与普通外圆磨削不同,砂轮周边与工件实际接触宽度并不恒等于砂轮宽度,点磨削变量角度和磨削深度显著影响砂轮周边的实际接触宽度与工件表面粗糙度 数值。 相似文献
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本文在分析砂轮磨钝过程中各种指标变化情况的基础上,选择合理的砂轮磨钝判断标准,并对此判据实现在线监测和预报。一、砂轮磨钝标志的选择1.砂轮磨钝过程的试验研究试验在MS1320外圆磨床上进行,用白刚玉、棕刚玉、绿碳化硅等砂轮对45淬火钢、GCr15轴承钢等材料的试件进行切入磨削试验,试验中采用了不同的磨削用量组合,观察、记录了磨削过程中多种指标的变化情况。由试验结果得知,在不同的试验条件下,每一种指标在磨削过程中的变化规律基本相同。图1~图3所示是其中一组试验的记录。该组试验采用的砂轮为GB60ZR1AP400×50×203… 相似文献
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采用正交试验法研究干磨和湿磨方式下砂轮线速度、工件转速、磨削深度对合金钢40CrNiMoA高速外圆磨削比能的影响,并建立基于BP神经网络的磨削比能预测模型,最后对预测结果进行验证。结果表明:合金钢40CrNiMoA高速外圆磨削比能随砂轮线速度增大呈现先增加后减小的趋势,随工件转速、磨削深度的增大而减小,工件转速对磨削比能的影响程度最大;湿磨方式的磨削比能比干磨方式的小。在试验工艺参数范围内,当砂轮线速度为60 m/s、工件转速为125 r/min、磨削深度为40μm时,磨削比能最小;预测模型的预测值与试验结果的绝对误差小于10%,表明BP神经网络预测模型是有效的。 相似文献
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《精密制造与自动化》1975,(2)
在外圆切入磨削时,采用径向磨削力、磨削功率或金属实际切除率的稳定系统不排除为保证被磨工件质量在加工循环结束时降低磨削用量的必要性。分析各种不同的加工循环可以认为,在加工过程中存在着与工件质量指标和工艺参数有关的磨削用量之最佳变化规律。加工循环可根据工件几何形状误差、波纹度、粗糙度、尺寸精度和烧伤等指标最佳化。对于宽砂轮来说,工件横截面内的几何形状误差是其主要质量指标在外圆切入磨削时,此项参数决定于工件和砂轮的旋转精度、磨削用量、振动程度和砂轮不平衡量等等。由磨削用量所决定的极限形状误差约相等于(在数量上)工件每转的进给量。 相似文献
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针对生产实际中采用的砂带磨削速度普遍与工艺手册的推荐值存在较大差距的问题,以砂带粒度、磨削速度、每转进给量、工件材料四因素进行正交试验设计,确定了各个参数对零件抛光质量的影响。列举了注胚模具型芯零件砂带低速抛光的工程案例,对该零件进行了工艺分析,编制了机械加工工艺,重点介绍了成型面的砂带低速抛光工序。试验结果的极差分析表明,砂带粒度对表面粗糙度的影响最大,远大于其他三因素,然后依次为工件材料、磨削速度,影响最小的是每转进给量;工程实践结果证明,只要选用的砂带粒度合适,即使选用较低的磨削速度,也可以取得良好的抛光效果。 相似文献
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Centerless grinding of ceramic components in the conventional above-center mode under aggressive conditions often results in workpiece spinning. One way to avoid workpiece spinning is to use below-center grinding, but this can lead to problems with part rounding and lobing. The present investigation was undertaken to develop a practical simulation to assist in the selection of acceptable set-up conditions for centerless grinding. From the initial workpiece profile and set-up conditions as input, the simulation predicts workpiece spinning and the progressive change in the workpiece profile for both above-center and below-center grinding. Simulation results for workpiece lobing were found to be consistent with experimental results obtained for below-center grinding of zirconia specimens. 相似文献
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Monitoring force in precision cylindrical grinding 总被引:1,自引:0,他引:1
Jeremiah A.Couey Eric R. Marsh Byron R. Knapp R. Ryan Vallance 《Precision Engineering》2005,29(3):307-314
Aerostatic spindles are used in precision grinding applications requiring high stiffness and very low error motions (5–25 nm). Forces generated during precision grinding are small and present challenges for accurate and reliable process monitoring. These challenges are met by incorporating non-contact displacement sensors into an aerostatic spindle that are calibrated to measure grinding forces from changes in the gap between the rotor and stator. Four experiments demonstrate the results of the force-sensing approach in detecting workpiece contact, process monitoring with small depths of cut, detecting workpiece defects, and evaluating abrasive wheel wear/loading. Results indicate that force measurements are capable of providing useful feedback in precision grinding with excellent contact sensitivity, resolution, and detection of events occurring within a single revolution of the grinding wheel. 相似文献
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I. Inasaki 《Precision Engineering》1985,7(2):73-76
An in-process surface roughness sensor developed by the author has been applied to cylindrical grinding operations. The sensor utilizes fibre optics to illuminate a workpiece surfacec and to detect the intensity of the reflected light. A change of surface roughness during one plunge grinding cycle is measured for various grinding conditions. It is confirmed by the measurements that the surface roughness is closely related to changes of the workpiece radius during a grinding cycle. The result is quite simple and it is useful in determining the cycle time of a grinding operation. 相似文献
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Geng Zhi Xuekun Li Zhiqiang Qian Haitao Liu Yiming Rong 《Machining Science and Technology》2016,20(4):615-633
The time-dependent performance of grinding is expressed as the change of process output measures as a function of time during grinding. Although the wheel capability will be restored by dressing, the time-dependent performance of grinding during one dressing skip is the determinant on the grinding quality variation in terms of surface integrity and workpiece geometric accuracy. Therefore, understanding of grinding time-dependent performance in relation with the wheel–workpiece microscopic interaction is critical for wheel and process development to achieve stable grinding processes. In this article, the grinding of superalloy with cubic boron nitride (cBN) grinding wheels is performed. The time-dependent performance is recorded to represent the characteristic features, and the microscopic wheel topography is measured under scanning electron microscope (SEM) throughout the grinding process, so as to reveal the root cause for the time-dependent performance and its impact on the workpiece quality variation. The experiment results indicate that during the grinding process, there exist three characteristic stages, namely, initial wheel wear stage, severe wheel wear stage, and wheel resharpening stage. Moreover, the change trend of spindle power consumption, workpiece quality on surface hardness and roughness, wheel wear condition, and G ratio are consistent with the wheel topography evolution reflected by SEM photos, which can be used to present the three grinding stages. The wear and replacement of the efficient grain cutting edges result in the time-dependent performance during superalloy high-speed grinding with cBN wheels. 相似文献
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通过确定移动热源的加载方式,运用ANSYS软件的热分析模块对磨削温度场进行仿真分析,得到了不同载荷步的温度场分布以及不同深度的节点的温度变化曲线,验证了越靠近热源磨削温度越高以及工件下层材料温升显著低于工件表面。通过改变砂轮线速度、工件进给速度和磨削深度,得到了主要的磨削参数对磨削区温度场的影响状况,证明了钛合金磨削存在临界磨削速度。在临界磨削速度附近某一区间磨削温度出现回落,因此适当的磨削速度、高的工件进给速度和小的磨削深度可以有效的减小磨削温度。 相似文献
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An experimental study on the grinding of alumina with a monolayer brazed diamond wheel 总被引:3,自引:3,他引:0
Jianyi Chen Hui Huang Xipeng Xu 《The International Journal of Advanced Manufacturing Technology》2009,41(1-2):16-23
A monolayer diamond grinding wheel was fabricated by brazing in vacuum. The wheel was then used to grind alumina at three different grinding speeds. The horizontal and vertical grinding forces, and the grinding temperatures were measured during grinding. SEM observations were made for the ground workpiece surfaces. The influences of the peripheral wheel speed on the grinding forces, specific grinding energy and grinding temperatures were analyzed under different combinations of depth of cut and workpiece velocity. The dependence of the average grinding force per grain and specific grinding energy on the maximum undeformed chip thickness was discussed respectively. It was found that an increase in the peripheral wheel speed reduced grinding force, but increased force ratio, specific grinding energy, and grinding temperature. 相似文献
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Abdolhamid Azizi Seyed Mehdi Rezaei Abdolreza Rahimi 《The International Journal of Advanced Manufacturing Technology》2010,47(9-12):1053-1063
A systematic research is conducted to investigate the effect of rotary cup dressing on vitrified cubic boron nitride grinding performance in grinding of nickel-based superalloys. Grinding performance is evaluated mainly in terms of specific grinding energy and radial wheel wear. The number of active grits per unit area and their slope is considered as the two grinding wheel topographical key parameters for studying grinding performance. Cup dressing conditions with various speed ratios and overlap factors were investigated. In each case, the specific grinding energy and the radial wheel wear were experimentally measured, and then the effect of changing dressing parameters on the grinding performance is analyzed. To provide a view on how various parameters influence specific energy and the importance of wheel topography and grit workpiece interaction, a new specific grinding energy model is developed. Inputs to this model are workpiece parameters, grinding process parameters, and, in particular, the grinding wheel topographical parameters. This model is validated by experimental results. The theoretical values considering the complexity of the grinding process reasonably compare with the experimental results. The effect of number of active grits per unit area and their slope on specific grinding energy and then metal removal mechanism is investigated. The results revealed that the number of active grits per unit area has less effect on specific grinding energy than grits slope. 相似文献