A precision grinding method for screw rotors using CBN grinding wheel

Aiming at the high precision machining of screw rotors, a new grinding method for screw rotors using cubic boron nitride (CBN) grinding wheel is presented in this paper. Small electroplated CBN grinding wheel is firstly used to grind screw rotors. The mathematical model for the axial profiles of CBN grinding wheel is developed based on gear engagement theory. Taking the backlash of screw rotors and the coating thickness of CBN layer into consideration, the modification of the base body of the wheel shape is introduced into the design of the CBN grinding wheel. Wire cut electrical discharge machining low speed (WEDM-LS) was used to machine the base body of the CBN grinding wheel. The formed turning tools of the base body of CBN grinding wheel using WEDM-LS and the wheel shapes of CBN grinding wheel using the formed turning tool were performed. The CBN grinding wheels for the screw rotors were made to verify the validity and effectiveness of the presented method. The electroplated CBN grinding wheels were used to machine the screw rotors, and the machining experiments were performed. The data obtained in the experiments reach the fifth class of Chinese Standard GB10095-88.     

Research on elliptical groove grinding for plunging constant velocity joint with basin grinding wheel

The theoretical error of elliptical groove in outer race of plunging constant velocity joint ground by finger grinding wheel is about 0.004 mm. In order to decrease the error, a new grinding method with basin grinding wheel is proposed. When we optimize the design parameters, the basin grinding wheel will avoid the problems that the feasibility and grinding accuracy are restricted by the interference of the head in the grinding process by means of finger grinding wheel, and can be used to ensure the machining precision and the sectional shape of the raceway to the greatest extent. Aiming at the grinding process with basin grinding wheel, the paper establishes the mathematical model, optimizes the parameters by using simplex algorithm, studies the processing principle in detail, and analyzes the machining errors. The simulation results indicate that the theoretical error for elliptical groove ground by basin grinding wheel will be reduced to 0.631 μm.     

螺杆压缩机转子成形砂轮刃形计算

针对给出任意转子型线时转子齿面加工的成形砂轮刃形设计,利用螺杆转子加工过程中转子和砂轮的相对位置关系,通过对转子型线坐标系的旋转变换,建立空间转子坐标系和成形砂轮坐标系之间的几何映射关系;基于啮合原理,建立转子齿面与成形砂轮的接触线方程,并给出解析和离散两种转子型线表达方式的刃形求解方法。在此基础上,根据转子砂轮之间的设计间隙,通过对接触线沿转子齿面法向进行偏置,获得了修整后的砂轮等距齿面刃形,避免了传统修整方法导致的法向齿间间隙不均等问题。加工结果表明,该方法能够满足螺杆转子的加工精度要求,是一种有效的螺杆转子齿面成形砂轮的刃形设计方法,并可推广应用于其他螺旋面成形砂轮或盘形铣刀的刃形设计。     

磨料粒度对电镀CBN砂轮磨损影响的有限元仿真分析

以单颗CBN磨粒的磨损为例,对电镀CBN砂轮的磨损进行研究。针对磨削淬硬轴承钢GCr15,将单颗CBN磨粒适当简化成圆锥体,建立楔形滑擦模型,利用Deform 3D软件对单颗CBN磨粒的磨耗磨损进行仿真分析。仿真结果表明:不同粒度磨粒的磨损形式相似,均为前端面磨成弧形月牙洼形,尖端逐渐磨成平台;相同条件下磨粒的最大磨损量随着磨料粒度号的增大而减小。同时也说明了细粒度的电镀CBN砂轮的磨损较小。研究结果对进一步研究电镀CBN砂轮制造工艺有指导意义。     

天线罩CNC修磨机床磨削轨迹计算

为了完成天线罩类大型复杂型面硬脆材料工件内廓型的测量与精密磨削，研制了天线罩CNC修磨机床；依据测量得到的天线罩内廓型离散数据和曲面上要求的各点去除量，经复杂数据处理后在计算机控制下，由电镀球形金刚石砂轮进行天线罩内廓型的精密磨削；根据天线罩内廓曲面的特点和加工要求，提出了一种刀具轨迹计算方法；在满足指定精度的情况下实现天线罩内廓曲面的高效率加工，使天线罩达到设计规定的性能指标。     

电镀金刚石砂轮高效精密修整及熔融石英磨削试验研究

大尺寸光学玻璃元件主要采用细磨粒金刚石砂轮进行精密/超精密磨削加工,但存在砂轮修整频繁、工件表面面形精度难以保证、加工效率低等缺点。采用大磨粒金刚石砂轮进行加工则具有磨削比大、工件面形精度高等优点,然而高效精密的修整是其实现精密磨削的关键技术。采用Cr12钢对电镀金刚石砂轮(磨粒粒径151 μm)进行粗修整,借助修整区域聚集的热量加快金刚石的磨损,可使砂轮的回转误差快速降至10 μm以内。结合在线电解修锐技术,采用杯形金刚石修整滚轮对粗修整后的电镀砂轮进行精修整,砂轮的回转误差可达6 μm以内,轴向梯度误差由6 μm降至2.5 μm。通过对修整前后的金刚石砂轮表面磨损形貌成像及其拉曼光谱曲线分析了修整的机理。对应于不同的砂轮修整阶段进行熔融石英光学玻璃磨削试验,结果表明,砂轮回转误差较大时,工件材料表面以脆性断裂去除为主;随着砂轮回转误差和轴向梯度误差的减小,工件表面材料以塑性去除为主,磨削表面粗糙度为Ra19.6 nm,亚表层损伤深度低至2 μm。可见,经过精密修整的大磨粒电镀金刚石砂轮可以实现对光学玻璃的精密磨削。     

Study on textured CBN grinding wheel by laser cladding

In this investigation, in order to improve bonding strength between superabrasive/metal matrix/grinding substrate, life span of grinding wheel, and grinding using small grits in continuous grinding simultaneously to fit for high speed and high precision machining in industry, coaxial powder feeding laser cladding method with CAD/CAM technology is introduced to manufacture textured CBN/CuSnTi–grinding wheels. The morphology of CBN grit on laser-cladding layer under optimized laser-cladding parameters and a pit created by fallen-off CBN on laser-cladding layer with lower laser–cladding energy density are observed by scanning electron microscope (SEM). The element distributions of interfaces of CBN/CuSnTi/AISI 1045 are analyzed by SEM and energy disperse spectroscope (EDS). The morphology and elements distribution of residual resultants on the surface of CBN grits etched by nitric acid are analyzed by SEM and EDS. Comparative-grinding process between laser cladding–grinding wheel (LCGW) and customized electroplated grinding wheel (EGW) is analyzed with grinding forces and temperature aspects respectively. The wear morphology of CBN grits on LCGW after grinding is observed by SEM. The results show that CBN grit with integrate cutting edges can protrude 50% height of its diameter on laser-cladding layer under optimized laser–cladding parameters. Fe, N, Ti, and B segregates attached to the interfaces of CBN/CuSnTi/AISI 1045 with Cu and Sn distributed uniformly in the laser-cladding layer. Residual resultants on CBN can be divided into two parts based on the distances from the surface of CBN grits. The grinding forces (Fz and Fy) and grinding temperature from LCGW are lower than those from EGW. The wear conditions of CBN on laser cladding are three parts: microfracture, cleavage plane, and wear-out.     

双导程ZN蜗杆修缘成形磨削研究

双导程ZN蜗杆(又称法向直廓蜗杆)修缘的精密加工需要研究一种成形磨削方法。传统的蜗杆修缘磨削方法是根据加工经验对砂轮进行手工修形,加工效率低且难以实现高精度的齿形修缘磨削。为此,以ZN蜗杆修缘齿形的成形磨削为目标,在蜗杆法平面引入齿形修缘分析,建立ZN蜗杆修缘齿形的数学模型,依据空间啮合原理计算出蜗杆磨削的成形砂轮截形,并利用数控砂轮修整装置修整砂轮。为验证蜗杆修缘的成形磨削效果,选用实际生产中的某一双导程ZN蜗杆,在自主研制的数控砂轮修整系统和工厂的蜗杆磨床上进行试验,经过对成形磨削砂轮计算、修整和蜗杆磨削,结果表明,磨削蜗杆的修缘量满足预期设计要求,蜗杆齿形精度达到6级。表明该方法可用于双导程ZN蜗杆修缘的高精度成形磨削。     

磨削弧区采用径向射流冲击强化换热的试验研究

在分析缓进给磨削烧伤机理的基础上,提出了高压射流冲击强化磨削弧区换热的创新构想,研制了带径向射流的ＣＢＮ 开槽砂轮试验装置,并通过缓进给断续磨削时采用径向射流冲击弧区的磨削试验研究其换热效果。结果表明,射流冲击强化换热技术可有效提高弧区换热效率,在解决难加工材料磨削烧伤方面具有广阔的应用前景。     

用于内圆磨的电镀CBN砂轮结构设计与分析

针对长径比大于6和直径约为Φ7mm的小直径深孔磨削加工,将内圆磨接杆和电镀CBN砂轮设计为整体式结构,利用ANSYS软件对此结构进行了静力学、模态和谐响应分析,得到了弯曲变形的位移值、固有频率及振型以及谐响应载荷下的动态响应特性。结果表明：此内圆磨具的结构设计满足静刚度和动刚度的要求,能够保证零件的加工精度和表面质量。     

数控成形砂轮磨齿机床几何误差分析与函数补偿法

以QCYK7332A数控成形砂轮磨齿机为例,对机床误差进行了分析。应用多体系统理论以及齐次坐标变换建立了几何误差模型,得到了此模型下砂轮尖的6个自由度误差表达式,并在此基础上以机床B轴为例,说明了运动轴误差转化到磨具上,从而引起所加工齿轮的齿距、齿形、压力角等误差。为了减小误差,提出了函数补偿法,并以测量机床的X轴角度误差为例,说明机床误差预测以及实时误差补偿的过程,为提高数控成形砂轮磨齿机精度、减小机床的几何误差提供了理论依据。     

螺旋槽螺纹铣刀的磨削砂轮设计

针对螺旋槽螺纹铣刀在磨削加工时内外侧磨削量不同的问题,通过齿形的数学建模和分析计算,提出了其磨削砂轮的修正量计算公式.同时编制了砂轮设计程序,实现了从螺纹铣刀参数到其磨削砂轮参数的自动转换.通过 AutoCAD 和 SolidWorks 应用开发,可以自动生成砂轮的二维图和三维模型.本文提出的方法可以提高螺纹铣刀磨削砂...     

Research on the technology for outer race elliptical groove grinding with basin-like grinding wheel

A new grinding method that outer race elliptic track in ball basket constant velocity joint is ground by means of basin-like grinding wheel is proposed herein. Aiming at the grinding process with basin-like grinding wheel, the paper establishes the mathematical model, optimizes the parameters by using restrictive random direction method, studies the processing principle in detail, and analyzes the machining errors. The simulation results indicate that the theoretical error of elliptical groove ground by basin-like wheel will be reduced to the level of 0.001 mm. Then, the grinding experiments of elliptical grooves with the basin-like grinding wheel were completed, and the measurements of the grooves by portable arm coordinate measuring machine were carried out, which validates the feasibility of this grinding technology.     

磨削等速万向节椭圆沟道的盆状砂轮研究

设计了一种用来磨削等速万向节椭圆沟道的盆状砂轮,因避免了砂轮头部的干涉,其参数优化的有效性和精确性得到了提高,能最大限度地保证加工截面的形状和精度;从模拟椭圆圆弧出发,根据待磨削的椭圆沟道方程进行设计,建立了盆状砂轮加工的数学模型,并对其加工原理进行了理论研究,对其加工误差进行了分析。仿真结果表明,用盆状砂轮磨削的椭圆沟道的理论误差可减小到0.7μm。     

感应钎焊温度对立方氮化硼砂轮磨削性能的影响

利用超高频感应钎焊在不同钎焊温度条件下制备立方氮化硼(CBN)砂轮,采用扫描电子电镜（SEM）和能量分散谱仪（EDS）对磨粒表面新生化合物进行观察与分析,并通过与电镀CBN砂轮进行比较,对感应钎焊CBN砂轮的磨削性能进行评价。结果表明：CBN磨粒界面新生化合物主要组成元素有N、B、Ti三种,活性元素Ti发生扩散并与N和B发生化合反应;当感应钎焊温度为940℃时,磨粒表面生成物致密覆盖在表面,且所制备的CBN钎焊砂轮的磨削力和磨削比能较小。在相同磨削用量下,对电镀CBN砂轮和感应钎焊CBN砂轮的磨损形式进行对比分析发现,电镀CBN砂轮的磨损形式为黏附磨损,钎焊CBN砂轮的磨损形式为破碎磨损。     

A study on the machining of compressor rotors using formed tools

In this paper it was suggested the machining method that can improve machining accuracy and reduce the machining time applying the formed tools based on the rotor shape feature to finishing machining for efficient machining of asymmetric rotors. For machining the complicated asymmetric rotor profile, machining area is divided and formed tools are manufactured based on the rotor feature., and the efficient machining method of screw motor was proposed using the formed tools and four axis machining devices. With the suggested machining method, machining time could be reduced compared to the general end mill machining method, and the machining errors of the proposed method could be within the allowable tolerance of the product so as to carry out the precise machining.     

电镀小直径CBN环形砂轮端面磨削沟槽底面

在对小直径环形砂轮端面磨削沟槽底面过程中的磨粒切屑厚度进行解析的基础上,设计了电镀小直径ＣＢＮ环形砂轮端部结构尺寸,作为提高砂轮寿命的措施,实验分析磨削冷却液供给方式和倾斜砂轮轴磨削法的效果。     

双圆弧砂轮偏心修整机构及牙形误差的研究

双圆弧砂轮偏心修整机构的设计是提高滚珠丝杠滚道精度的关键。采用导轨式，斜块式，凸轮式，螺钉式和转轴间隙式机构可实现偏心修整。金刚行修整砂轮误差使滚道在磨削地产生非圆牙形误差。     

电镀CBN锥砂轮磨齿热状态的研究

通过对磨齿过程中砂轮与工件系统的分析 ,建立了锥砂轮磨齿热状态分析模型 ,并分别运用一维传热杆模型及有限单元法分析、计算了磨削所引起的齿面表层的温度场 ;同时 ,用电镀CBN、陶瓷CBN和刚玉砂轮做模拟磨齿试验 ,考察了不同的砂轮及工艺参数对齿面温度的影响。结果表明 ,试验结果与计算结果基本吻合 ,电镀CBN锥砂轮磨削所引起的齿面温升仅是刚玉砂轮的 5 0 % ,比陶瓷CBN砂轮亦低。     

树脂基圆弧金刚石砂轮的在位精密成形修整技术

针对球面、非球面及自由曲面超精密磨削加工用树脂基圆弧形金刚石砂轮难以精密修整的问题,提出基于旋转绿碳化硅(GC)磨棒的在位精密成形修整技术。在分析GC磨棒和圆弧砂轮几何关系的基础上,确定修整过程中圆弧插补轨迹的补偿方法及GC磨棒运动轨迹的设计方案。采用KEYENCE激光测微仪采集砂轮圆弧特征点,表征圆弧砂轮的修整状况。研究不同粒度的GC磨棒、进给深度和圆弧插补速度对圆弧金刚石砂轮修整率和修整精度的影响规律。研究结果表明,该修整方法可根据加工曲率半径要求实现不同圆弧半径砂轮的精密在位修整,修整后可自动消除砂轮垂直方向的位置偏差;采用400#和800#的GC磨棒对D3和D7砂轮均有较高的修整率(0.7~6.7);与400#和1500#的GC磨棒相比,800#GC磨棒更适合粒度为D3和D7圆弧金刚石砂轮的精密修整;相比圆弧插补速度,进给深度对砂轮的圆弧半径尺寸误差和形状误差影响更大,进给深度越小,圆弧半径尺寸误差和形状误差越小;修整后两种砂轮的圆弧半径误差均可控制在5%以内,D3砂轮的形状误差可控制在3μm/4 mm以内,D7金刚石砂轮可控制在6μm/4 mm以内,修整后比修整前形状误差提高14倍左右。