VMC0540d机床床身和立柱结构的谐响应分析

首先给出了分析机床床身和立柱结构动态特性的重要性和必要性,并给出了对其进行 谐响应分析的意义.给出了配置ANSYS和PROE接口的方法和有限元模型的生成的具体过程.在对谐响应求解方法进行对比分析的基础上,对VMC0540d的床身和立柱结构进行了谐响应分析,得到了床身和立柱关键点沿机床的X、Y和Z向在频域的应力和位移谐响应曲线.最后,对谐响应分析的结果进行了具体说明,给出了机床受迫振动时振源的频率范围,同时也说明了谐响应分析的局限性.     

带锯床锯切负载检测系统研制

针对金属带锯床对锯切高精度、高效率等方面提出的要求,设计了一种带锯床锯切负载检测系统,提出了一种基于粗糙集数据分析方法(RSDA)的专家系统智能识别策略。该系统实时采集带锯锯切振动信号,经信号处理模块提取特征值,专家系统将提取的特征值暂存于数据库,经过诊断模型的对比分析,对锯切负载进行识别。研究结果表明,该锯切负载检测系统具有识别准确率高、响应速度快等特点,其检测精度可以达到负载检测量程的1‰,可以较好地满足带锯床锯切负载在线识别的需要。     

TX1600镗铣加工中心立柱动态特性分析

用Sofidworks软件建立三维实体模型,在三维实体模型的基础上建立了TX1600镗铣加工中心立柱模态分析的有限元模型,用ANSYS有限元分析软件对它进行模态分析,通过求解得出前4阶固有频率和相应的主振型。为了解各阶频率对结构动载荷的响应情况,论文还将对TX1600数控加工中心立柱进行谐响应分析,结果得出数控中在受外部激振力下的动态响应特性,并在此基础上指出了机床存在的不足。     

基于ANSYS的管子车床主轴动力学分析

借助有限元分析软件ANSYS,对一种具有径向进给功能的管子车床主轴系统进行三维建模,然后选择六面体单元Solid95进行网格划分和模态求解,计算出主轴系统的前五阶固有频率及其振型,验证了主轴系统的固有频率远高于发生共振的临界频率。通过加减谐载荷,在模态分析的基础上进行谐响应分析,计算出主轴系统在激振力作用下的响应位移与响应应力,得到系统的动力响应与系统振动频率的曲线,即幅频曲线,验证了该主轴结构能经受住不同频率的各种正弦载荷。经过以上动态特性的研究,获得了机床主轴组件的动态参数,为机床主轴组件设计和结构改进提供了重要依据。     

基于小波分析的带锯床锯条振动检测方法

由于带锯床锯条振动检测的过程中没有对振动信号进行预处理，导致检测准确性较低，致使锯切作业中易发生安全事故。基于此，提出基于小波分析的带锯床锯条振动检测方法。创建将电涡流传感器线圈与电容并联，设计LC并联谐振回路，通过薄板基本理论，分析带锯床锯条在进行锯切作业时产生的振动情况，构建带锯条锯切振动数学模型，获取带锯条锯切振动信号，通过连续小波变换方法对振动信号进行预处理，根据处理结果及弦振动理论，计算带锯条锯切振动行波频率，并以此为基础，检测带锯床锯条振动的情况。实验结果可知，所提检测方法的准确性较高。     

带锯床无死角锯切金属下料工艺探讨

应目前机械行业产品设计的技术要求,需要在生产过程中完成各类型钢斜角的下料,因此对带锯床无死角锯切金属下料工艺展开研究。分析了带锯床的工作原理以及下料工艺操作过程。经试验证明,通过在带锯床上加装辅助胎具,可以实现带锯床无死角锯切。     

圆线波形弹簧的结构动力学分析

以圆线波形弹簧为研究对象,针对圆线波形弹簧的自振频率和弹簧受迫振动的振幅两个基本性能,对其进行模态分析和谐响应分析。首先利用三维软件UG进行实体建模并将模型导入Workbench软件,对模型进行有限元求解,获得其模态特性和谐响应特性。通过对波形弹簧的数值仿真,确定弹簧的自振频率,得到弹簧在谐载荷作用下的幅频响应。为圆线波形弹簧的设计和使用提供了一定的参考。     

电子开料锯在多种工况下的静态特性分析

随着木工产品的广泛应用,对木材加工机械的研究也越来越多。电子开料锯作为重要的木工机械之一,其主要工作是对板料进行锯切,它工作台的应变大小直接影响到木板的形变量,这是影响木板锯切质量好坏的重要因素。通过有限元计算方法,对电子开料锯在多种特殊工况下的静态特性做了详细分析,得到整机应力情况和工作台的应变云图。结果表明:工作台的应变在允许范围内,设计结构是合理的。同时此静态特性分析也为后期做开料锯整机的模态分析、谐响应分析以及结构上的改进与优化奠定了基础。     

带锯床专用调速阀的设计与应用

根据带锯床在锯切工件过程中的实际要求,设计了进给系统中的主要元件———调速阀。实践证明：所设计的调速阀能稳定锯切精度,延长锯条寿命,实现了锯切的最佳状态。同时,应用于各种类型的带锯床上,收到了很好的使用效果。     

单搭压印连接接头的谐响应分析

介绍了压印连接的特点和谐响应分析的原理,采用有限元分析软件ANSYS建立了单搭压印连接接头的有限元模型,并进行预应力静力分析和预应力模态分析,在此基础上对此模型进行了谐响应分析。对比了不同预应力下固有频率的变化,共振时谐响应位移峰值的变化。     

节能气动系统

多种多样的气动系统在自动化和半自动化生产中发挥了重要作用。随着气动技术的不断应用,它消耗的能源也不断地增长,因此在气动技术的应用中,如何节约能源是十分迫切需要解决的问题。众所周知,气动系统中的执行器——气缸是用压缩空气来推动的,而做过功但还具有一定能...     

摩擦锯切机理的研究

研究了摩擦锯切钢管的锯切过程、锯切温度规律、摩擦温度的恒定效应及摩擦图形等摩擦锯切的基本问题。     

Analysis of the diamond sawing process

There are three methods in use for separating diamonds, i.e. by cleaving, by laser beam and by sawing. Sawing is one of the main methods used for this purpose. This operation is carried out on special sawing machines equipped with a sawing disk blade, 0.04–0.14 mm thick and 76 mm initial diameter. The rotational velocity (n) of the disk is between 6000 and 12 000 r.p.m. Diamond powder is embedded in the periphery of the disk. The outcome surface of a diamond after the sawing operation must be flat and smooth, Whenever such a surface is actually obtained, the polishing time and the loss in size and weight of the diamonds are reduced.In the present work, the positioning of the diamond to be sawed, with respect to an embedded particle in the disk, to create a favourable cutting angle is discussed. This would make it possible to reduce the rake angle () to near-zero, and thereby the cutting forces. Furthermore, a method to control the morphology and grain size of the diamond powder to be used in the cutting was developed.In the diamond industry, two modes of sawing operations are in practice. One uses the periphery of the disk for the sawing while the other employs a circular hole in the centre of the disk. Analysis of the two modes showed that the hole mode is more promising, as the design in that case requires tensioning of the disk and makes for better lateral stability during the sawing process. In addition the tangential and the radial stresses, developed in both sawing methods, were calculated. To support the above, data was obtained from existing literature and analysed.Nomenclature n rotational velocity of the disk, r.p.m. - rake angle, degrees - back clearance angle, degrees - cutting angle, degrees - m relative frequency - f feed - b disk radius, mm - a disk hole radius, mm - r current disk radiusb>r>a, mm - density of disk material, kg m^–3 - angular velocity - Poisson ratio of disk material - g acceleration of gravity, m s^–2 - _r radial stress, kg cm^–2 - _{r max} highest radial stress, kg cm^–2 - _t tangential stress, kg cm^–2 - tangential stress at outside circumference, kg cm^–2 - tangential stress at inside circumference, kg cm^–2     

A new sawing machine by diamond wire

Diamond wire is widely used for stone cutting; it is typically employed to extract a block in quarry and to square the block in a machining company. In particular, the frames to square or to cut the blocks present many technological limits, such as the high costs of the diamond wire, the frequent break of the diamond wire during cutting, the poor quality of cut surfaces, and the dangerous process and productivity lower than that of the same tool used in a quarry. The present work shows an innovative prototype machine to cut by a diamond wire which overcomes the aforementioned technological limits. The developed machine has a bridge frame among which two pulleys move the diamond wire as regards the stone block according with the feed speed. The diamond wire moves on the two pulleys with a cutting speed. A tensile force is applied to the wire that twists it during the contact with the stone, instead of keeping it along a straight direction parallel to the foundation of the machine. The twisting of the diamond wire makes the use of the wire itself more productive and safer, since the wear of each single bead during cutting is more uniform. Moreover, the resulting specific pressure acts on each bead along the arc of contact with the cut block and increases along the cutting direction from the entrance to the exit of the contact with the stone. The increasing of the specific pressure causes a bending of the diamond wire during the contact with the stone. The developed prototype was provided with a sensory system to measure both the cutting power and the tensile force of the diamond wire during experimental tests. In this way it was possible to verify the functionality of the prototype plant and, in the same time, to evaluate the productivity of the implemented cutting process.     

石材锯切加工工艺分析研究

从锯切加工过程出发,研究了盘锯加工石材的特征及其参数ε,列出了ε的表达式,分析了一些重要的工艺参数,得到了一些对进一步深入研究和生产实践有指导意义的结论.     

热锯机主轴轴承润滑方式改进

分析了热锯机主轴轴承故障率较高的原因，根据使用要求及使用环境重新选择了润滑剂，并对轴承座及主轴箱结构简化改进，根治了热锯机主轴轴承损坏频繁的顽症。     

PLC控制定尺飞锯

介绍了PLC控制焊管定尺飞锯的设计思想和控制原理,并提出了提高定尺精度的几点措施.该系统在生产过程中,可靠性高,定尺精度可达到±5mm.     

Effects of magnetic field distributions on wire sawing performance

To transport more abrasive grains into the cutting zone, the method of magnetic-induction free-abrasive wire sawing is proposed. A uniform magnetic field is used to magnetize a steel wire and forms a high gradient magnetic field around the wire. The magnetic abrasive grains are adsorbed on the magnetized wire and are transported into the cutting zone, which improves the wire sawing performance. The adsorption of the magnetic abrasive grains is observed using an experimental setup along the wire cross-sectional direction. The results suggest that magnetic abrasive grains are increasingly adsorbed in the paramagnetic region of the wire with increasing magnetic field intensity. Single-wire sawing experiments are conducted on a WXD170 reciprocating wire sawing machine at variable magnetic field intensity and distribution. The results suggest that the change in magnetic field intensity strongly affects the cutting efficiency, kerf loss, and surface roughness. The performance of the magnetic-induction free-abrasive wire sawing under different magnetic field intensities and distributions are compared. The wire sawing performance improves when the uniform magnetic field is evenly distributed in the cutting zone and at the top of cutting zone.     

Friction studies on the process in circular sawing of granites

An investigation is reported of the friction characteristics of the process in circular sawing of granites with diamond segmented sawblade. The sawing forces were measured and specific sawing energies were calculated in sawing five types of typical granite at specific removal rates ranging from 25 to 200 mm²/s. Coupled with SEM observations of the sawn granite surfaces, a quantitative analysis for sawing energy suggests that most of the sawing energy should be expended by friction of sliding between diamonds and granites. The effect of sliding friction was discussed by introducing a new quantity which is called mean chip longitudinal area. This revised version was published online in August 2006 with corrections to the Cover Date.