Contact Mechanism of Rail Grinding with Open-Structured Abrasive Belt Based on Pressure Grinding Plate

The current research of abrasive belt grinding rail mainly focuses on the contact mechanism and structural design.Compared with the closed structure abrasive belt grinding,open-structured abrasive belt grinding has excellent performance in dynamic stability,consistency of grinding quality,extension of grinding mileage and improvement of working efficiency.However,in the contact structure design,the open-structured abrasive belt grinding rail using a profiling pressure grinding plate and the closed structure abrasive belt using the contact wheel are different,and the contact mechanisms of the two are different.In this paper,based on the conformal contact and Hertz theory,the contact mechanism of the pressure grinding plate,abrasive belt and rail is analyzed.Through finite element simulation and static pressure experiment,the contact behavior of pressure grinding plate,abrasive belt and rail under single concentrated force,uniform force and multiple concentrated force was studied,and the distribution characteristics of contact stress on rail surface were observed.The results show that under the same external load,there are three contact areas under the three loading modes.The outer contour of the middle contact area is rectangular,and the inner contour is elliptical.In the contact area at both ends,the stress is extremely small under a single concentrated force,the internal stress is drop-shaped under a uniform force,and the internal stress under multiple concentration forces is elliptical.Compared with the three,the maximum stress is the smallest and the stress distribution is more uniform under multiple concentrated forces.Therefore,the multiple concentrated forces is the best grinding pressure loading mode.The research provides support for the application of rail grinding with open-structured abrasive belt based on pressure grinding plate,such as contact mechanism and grinding pressure mode selection.

Allowance Extraction Considering of Inner and Outer Contour and Experimental Research on Belt Grinding of Hollow Blade

Aero-engine fan blades of ten use a cavity structure to improve the thrust-to-weight ratio of the aircraft.However,the use of the cavity structure brings a series of difficulties to the manufacturing and processing of the blades.Due to the limitation of blade manufacturing technology,it is difficult for the internal cavity structure to achieve the designed contour shape,so the blade has uneven wall thickness and poor consistency,which affects the fatigue performance and airflow dynamic performance of the blade.In order to reduce the influence of uneven wall thickness,this paper proposes a grinding allowance extraction method considering the double dimension constraints(DDC)of the inner and outer contours of the hollow blade.Constrain the two dimensions of the inner and outer contours of the hollow blade.On the premise of satisfying the outer contour constraints,the machining model of the blade is modified according to the distribution of the inwall contour to obtain a more reasonable distribution of the grinding allowance.On the premise of satisfying the contour constraints,according to the distribution of the inwall contour,the machining model of the blade is modified to obtain a more reasonable distribution of the grinding allowance.Through the grinding experiment of the hollow blade,the surface roughness is below Ra0.4μm,and the contour accuracy is between-0.05~0.14 mm,which meets the processing requirements.Compared with the allowance extraction method that only considers the contour,the problem of poor wall thickness consistency can be effectively improved.It can be used to extract the allowance of aero-engine blades with hollow features,which lays a foundation for the study of hollow blade grinding methods with high service performance.

基于麻雀算法优化神经网络的螺杆砂带磨削去除深度预测

目的准确获得螺杆转子砂带磨削材料去除深度,探究工艺参数对材料去除深度的影响。方法通过分析螺杆转子砂带磨削去除机理,确定材料去除深度影响因素。提出一种基于麻雀算法优化长短时记忆网络-卷积神经网络模型(SSA-CNN-LSTM),对螺杆转子砂带磨削加工中的材料去除深度进行预测。以磨削中影响材料去除深度的因素为输入,磨削深度为输出,构建利用SSA对CNN-LSTM超参数进行寻优的预测模型,并且与CNN-LSTM、LSTM、PSO-BP、RBF以及随机森林预测方法进行对比。结果所提预测方法平均绝对百分比误差MAPE可达0.0461,均方根差RMSE为9.261,平均绝对误差MAE达7.836,确定系数R^(2)为0.9974,相比于未优化CNN-LSTM网络和其他经典网络模型,预测精度更高,能够有效预测螺杆转子磨削材料去除深度。利用提出的模型探究了磨削工艺参数对材料去除深度MRD和材料去除一致性的影响。由预测结果可知,螺杆转子砂带磨削材料去除深度随法向压力、砂带线速度增加而增大,随进给速度、砂带目数增加而减小,且受法向压力影响最明显。通过对磨削前后工件廓形进行分析可知,材料去除深度随磨削区域受到的法向压力呈现中间磨削深度大、两侧逐渐减小的趋势。结论提出的预测模型预测效果显著,分析了工艺参数对磨削材料去除深度和去除一致性的影响规律,可为其他类型的加工轮廓预测提供参考。

Single-grain cutting based modeling of abrasive belt wear in cylindrical grinding

A systematic wear model of the cylindrical grinding process with an alumina abrasive belt from the perspective of single grain sliding wear was established in this study.The model consists of three parts:a single cutting force model derived by applying a stress integration method,a single grain wear height analysis based on the wear rate of alumina,and a grinding mileage prediction of multiple grains with Gaussian distributed protrusion heights.Cutting force,single grain wear height and full‐size grinding mileage verification experiments were conducted.The results indicated that the established model was in reasonable agreement with the experimental outcomes,which suggests that this model could be useful in the industry to predict the wear process of abrasive belts.

A Novel Approach for the Fabrication of Sharkskin Structured Bionic Surfaces with Hydrophobic Wettability:Laser Processing and Ordered Abrasive Belt Grinding

A new process for the fabrication of sharkskin bionic structures on metal surfaces is proposed.The sharkskin bionic surface was successfully machined on the surface of IN718 by laser sequencing of the abrasive belt surface,laser processing of the layered scale-like structure,and ribbed texture grinding.The flexible contact properties of belt grinding allow ribbed structures to be machined uniformly on a hierarchical,scale-like microstructure.Sharkskin bionic microstructures with radii greater than 75µm were prepared after parameter optimisation.The influence of processing parameters on the geometrical accuracy of the microstructure was investigated,the microstructure microform and elemental distribution were analyzed,and the relationship between the ribbed microstructure and chemical properties of the surface of the bionic sharkskin on wettability was revealed.The results indicate that reducing the laser power and increasing the laser scan rate can reduce the laser thermal effect and improve the microstructure processing accuracy.The laser ablation process is accompanied by a violent chemical reaction that introduces a large amount of oxygen and carbon elements and infiltrates them at a certain depth.The wettability of the surface undergoes a transition from hydrophilic(contact angle 69.72°)to hydrophobic(contact angle 131.56°)due to the adsorption of C-C/C-H and the reduction of C=O/O=C-O during the placement process.The ribbed microstructure changes the solid-liquid contact on the surface into a solid-liquid-gas contact,which has an enhanced effect on hydrophobicity.This study is a valuable guide to the processing of hydrophobic layered bionic microstructures.

The Method and Experiment Research on Down-stroke Abrasive Belt Grinding under Micro Feeding for Noise Reduction Surface

This paper proposes a down-stroke abrasive belt grinding under micro feeding for noise reduction surface.Firstly,a physical model of processing under micro feeding for noise reduction structure was established.Based on the flexible contact characteristics of abrasive belt grinding and Hertz contact theory,a mathematical model suitable for this method was established,considering vibration and abrasive belt wear.Secondly,a simulation analysis was carried out.Then,an experimental platform was built to analyze the influence of process parameters on surface roughness and surface microstructure,with the model verified.Finally,the propeller with pit structure was simulated,and the noise reduction performance of the propeller under this method and general abrasive belt grinding was compared and analyzed.The results show that the maximum error of the model based on proposed method does not exceed 10%,and the coincidence degree of the minimum error point can reach 90%at lower feed speed and higher linear velocity of the abrasive belt.The noise reduction effect of the propeller with pit-shaped surfaces can reach 35%.Through the above analysis,the proposed method can be used for the processing of noise reduction surfaces.

基于驻留时间控制的压气机叶片前缘砂带磨削研究

提出了一种面向叶片前缘廓形精准控制的机器人砂带磨削加工方法.以轴流压气机叶片为研究对象,结合半赫兹接触理论和有限元仿真获取了柔性磨具和叶片前缘的接触区域内的应力分布,基于Preston方程求解材料去除函数.遍历刀位点对控制点的磨削深度,建立全局材料去除矩阵,搭建驻留时间求解非线性方程组.采用带有阻尼因子的Tikhonov正则化消除大型稀疏病态矩阵对求解精度波动的影响,将所求驻留时间转换为对应刀位点的进给速度,生成机器人加工代码.磨削试验结果表明,基于驻留时间控制的机器人砂带磨削方法能够实现给定允差范围内叶片前缘廓形的精准加工,型面误差可以控制在0.02mm以内.

面向钢轨修复的不同槽型接触轮砂带打磨接触行为及材料去除特性

为掌握不同槽型接触轮砂带对钢轨打磨接触行为及材料去除特性的影响规律,基于橡胶接触特性,建立X齿型、锯齿型和人字型3种典型接触轮砂带打磨仿真模型,模拟分析不同槽型特征对接触轮-钢轨静态接触行为和动态冲击应力的影响机制;通过钢轨砂带打磨试验,对比研究3种槽型接触轮的材料去除特性。结果表明:3种槽型接触轮与钢轨的接触区域整体均呈椭圆形态,符合赫兹接触理论,内部接触形态则随槽型特征呈现为块状分布;接触区域应力分布总体符合弹性半空间接触理论,但在接触块边缘会出现应力集中;X齿型接触轮和人字型接触轮因齿尖和齿槽结构的存在而具有较高的材料去除能力,同等打磨条件下X齿型接触轮较平型接触轮的材料去除能力提高了79%;顺磨条件下的材料去除能力高于逆磨,以X齿型接触轮为例,顺磨比逆磨的材料去除能力提高了22.7%;X齿型和人字型接触轮砂带打磨的噪声、振动、粗糙度、平均电流均较高,锯齿型接触轮具有较低的振动、粗糙度及平均电流,平型轮则具有较低的噪声和电流。

复杂曲面机器人砂带磨抛材料去除深度预测模型及试验研究

针对复杂曲面零件的磨抛过程中曲率半径对机器人砂带磨抛加工中型面精度的影响,开展基于多曲率半径镍基高温合金的机器人磨抛加工试验研究。主要探究不同曲率半径的试验件的磨抛加工性,对不同曲率半径的镍基高温合金试验件进行砂带磨抛加工设置相应的砂带粒度和磨抛工艺参数,采集试验件的材料去除深度,并对试验结果进行研究分析。试验结果表明,曲率半径的变化对材料去除深度存在着一定的影响,在曲率半径由大到小的变化中,材料去除深度也随之增加,即材料去除深度与曲率半径呈负相关关系。基于多元非线性回归模型提出关于砂带粒度、进给速度、接触力、工件曲率半径等影响因素的机器人砂带磨抛材料去除深度预测模型,模型的平均预测误差为1.45μm,准确率达到91.04%,预测误差区间为–5.34~4.57μm,并对预测模型进行显著性检验,表明该预测模型可为实际机器人砂带磨抛加工前期工艺参数设计提供重要的理论支持。

基于PSO-LSSVR的机器人磨抛材料去除模型

为了建立磨抛工艺参数与材料去除深度的关系,建立一种基于最小二乘法支持向量回归机(LSSVR)的材料去除深度预测模型,并引入粒子群优化(PSO)算法来优化LSSVR的超参数,可提高LSSVR模型的预测准确性和全局优寻能力。搭建叶片机器人砂带磨抛实验平台,设计并进行多工艺参数实验,考虑工艺参数:砂带粒度、砂带转速、进给速度、接触力和叶片表面曲率半径,获得叶片表面的材料去除深度,最终利用实验数据建立了PSO-LSSVR叶片材料去除深度预测模型。结果表明,PSO-LSSVR模型的预测准确率为95.37%,平均预测误差为0.003463,说明PSO-LSSVR模型具有较高的预测精度,并结合实际加工情况进行实验验证可行性,证明PSO-LSSVR模型可以有效合理地建立工艺参数与材料去除深度的关系。

工业机器人磨抛柔性加工单元磨削参数识别方法优化试验

为解决工业机器人磨抛柔性加工单元因砂带磨损导致工件磨削量减少、被加工工件表面质量一致性差的问题,提出建立基于砂带磨削参数识别方法,以此作为判断砂带磨损程度依据,并进行相应的补偿。在分析砂带磨削参数的理论基础上,设计基于磨削力、磨削深度、砂带粗糙度、砂带厚度、磨削量5种不同的磨削参数识别方法,并通过试验测试,分析优化出砂带磨削参数识别方法,即通过调整磨削参数,补偿因砂带磨损而减少的工件磨削量,可有效保证加工表面一致性。

金字塔砂带磨损状态的声信号GA-BP识别方法

目的金字塔砂带连续磨损会引发钝峰、材料去除能力差和产热多等问题,为避免砂带磨损造成加工效率持续降低和工件表面质量逐渐恶化,需提高金字塔砂带磨损预测能力。方法在配有声音采集系统的力控机器人磨削系统中对钛合金工件进行了砂带磨损试验;基于Archard模型建立了金字塔砂带磨损模型,并对金字塔砂带磨损程度进行量化;然后利用短时傅里叶和小波包分解分析、提取砂带磨损相关的声音特征;基于声音信号特征建立GA-BP模型,并对金字塔砂带磨损状态进行预测。结果K_(r)与R_(0)规律相近,随着磨削速度的增大而略微增大。对磨削声音进行小波包分解,DD2频段的声音特征随磨削时间逐渐降低,相较于其他频段更具有规律性。提取DD2频段的声音信号特征建立GA-BP模型,并对金字塔砂带磨损状态进行预测。结果表明,决定系数(R^(2))大于0.8,平均绝对误差(MAE)小于0.04,平均偏差误差(MBE)在±0.002之间,均方误差(RMSE)小于0.05。结论随着砂带的磨损,金字塔尖锐的胞体开始磨平,单颗胞体的局部压力逐渐减小,材料去除能力减弱,产生的微振荡越来越弱,高频信号的声音特征逐渐下降。通过DD2频段声音信号特征建立的GA-BP模型对金字塔砂带磨损状态进行预测,具有准确性和稳定性。

《线材用砂带除锈机技术规范》行业标准制定解释

介绍制定行业标准《线材用砂带除锈机技术规范》的任务来源、工作程序和编制准则,对标准中的主要条款进行解释。标准主要内容包括术语与定义、型式及基本参数、订货要求、技术要求、试验方法、检验、标志包装运输与贮存、质量保证等。标准制定避免了用户与设备制造商之间质量异议,推动了钢丝用线材、热处理半成品钢丝表面氧化铁皮的绿色处理工艺。

砂带磨削技术及材料的研究现状和发展前景

概述了砂带磨削的机理和特点,综述了国内外砂带磨削技术的研究现状,重点分析和讨论了砂带磨削技术、砂带磨削理论、砂带磨削材料等方面的进展和存在的问题,展望了砂带磨削技术的发展趋势。

不锈钢材料砂带磨削试验

不锈钢材料具有优良的性能,应用广泛,但属于难磨材料.砂带磨削具有良好的磨削加工性能,笔者采用4种磨料砂带对不锈钢材料进行磨削试验.研究了磨粒与工件在磨削过程中的交互作用机理,讨论了影响材料去除率的因素,用SEM分析了加工表面显微形貌特征,揭示了材料的去除机理和砂带磨损形式.

高速高效磨削加工及其关键技术

介绍了超高速磨削、高效深磨、缓进给磨削和砂带磨削等各种高效磨削,比较了各种磨削工艺的效率及应用参数范围。分析了高速高效磨削的关键技术,阐述了实现高速高效磨削的主要途径。

自由曲面六轴联动砂带磨削机床试验

提出了一种以汽轮机叶片为典型对象的自由曲面高效精密加工方法,建立了基于砂带磨削原理的自由曲面六坐标联动磨削与抛光系统,研究了该机的关键技术如双摆动磨头、自由曲面磨削数控编程软件和冷缺排屑系统,在此基础上利用该机对叶片表面进行了六轴联动砂带磨削抛光试验验证,为确定合理的汽轮机叶片抛光工艺参数提供了依据。

高效率磨粒加工技术发展及关键技术

高效率磨粒加工是先进制造方法的重要组成部分,集粗精加工与一身,达到可与车、铣和刨削等切削加工方法相媲美的金属磨除率,而且能实现对难磨材料的高性能加工。阐述了高速超高速磨削、快速点磨削、高效深切磨削、缓进给磨削、高速重负荷荒磨以及砂带磨削等高效率磨粒加工技术的国内外的发展及最新研究进展。研究了高效磨削砂轮、主轴及其轴承技术、高效率磨床、磨削液供给技术、砂轮、工件安装定位及安全防护技术以及磨削状态检测及数控技术等实现高效率磨粒加工的关键技术,分析了发展高效率磨粒加工的重要性。

Zr-4合金管砂带随形磨削实验分析

采用3种不同磨料的砂带对Zr-4合金管进行了磨削工艺试验,探究了磨粒与工件间的交互创成机理,得到了Zr-4合金材料砂带磨削过程中材料去除率和表面粗糙度的主要影响因素。借助先进的测试设备,对磨削后的砂带磨粒磨损形貌、工件表面形貌进行了观测,并对Zr-4合金表面烧伤层金相组织及显微硬度变化规律做了分析研究。试验结果表明:砂带线速度、磨削压力、接触轮硬度和磨料种类对材料去除率和表面粗糙度均有较大的影响,其中砂带线速度影响最为显著;锆刚玉和氧化铝磨粒的粘附磨损较为严重,碳化硅磨粒主要以磨耗磨损为主;工件烧伤时材料表层金相组织发生变化,使得Zr-4合金物理机械性能下降。试验及研究结果为寻求高效、高精度Zr-4合金砂带磨削加工工艺提供了试验和理论依据。

基于钛合金砂带磨削的磨削率、表面质量及砂带寿命性能试验研究

针对钛合金磨削加工磨削率低,砂带使用寿命短以及表面质量差等问题,文章分别用正交实验和单因素实验对砂带磨削钛合金的磨削率及表面质量进行了一系列的性能实验研究,得到了十分有用的结论。论文的研究不但可以改善钛合金的表面质量,提高钛合金的磨削率,而且有助于扩大钛合金的应用范围,延长砂带的使用寿命,对生产实践有理论指导意义。