陶瓷抛光机空载阶段能耗建模与仿真

抛光砖在建筑行业中应用越来越广泛。瓷砖抛光是抛光砖制备过程中一道高耗能工序,消耗30%～40%抛光砖的生产能耗。陶瓷抛光机作为抛光工序中主要使用的装备,具有加工机理复杂、多能耗类型、能量流动规律复杂等特性。以抛光机空载阶段为研究对象,分析抛光机内部能流,确定高耗能部件,建立其相应的能耗模型并进行误差分析。用Matlab软件进行仿真实验,仿真结果表明建立的能耗模型是合理的。     

基于Fluent的磨粒流抛光工艺数值分析

磨粒流抛光技术是一种先进且精密的制造工艺,因其使用可流动的磨粒作为"刀具"对待加工表面进行抛光,不受零件形状和尺寸限制,现已成为抛光微小孔道及复杂成型面的主要技术,本文基于Fluent仿真软件,以喷油器为研究对象,对不同压强进行数值仿真,分析加工效果。     

模具电化学抛光的优越性

模具的抛光现在仍然是一个难题。一般是机械旋转抛光及超声波抛光，但对电化学抛光还比较生疏，缺乏这方面的技术及经验。文中介绍一种电解抛光设备，为模具及复杂工件的抛光探索了一条行之有效的途径。     

自动变速器油泵流场与噪声分析

汽车自动变速器油泵内部流场十分复杂，而复杂的流体流动直接影响其振动噪声问题。通过建立自动变速器油泵流场仿真模型模拟其内部流场流动，重点分析了油泵的压力脉动情况与空化特性，并结合仿真流量值与实验值及理论值对比，验证了模型的有效性。对油泵流动噪声进行声学模拟，结合声场仿真分析与流场仿真结果研究了压力脉动与流动噪声的关系。结果表明自动变速器油泵的噪声频率成分以离散噪声为主，压力脉动是油泵噪声的主要激励源。     

用于模具自由曲面的新型气囊抛光中磨粒场的分析

为提高模具自由曲面抛光的效率和品质,提出一种基于柔性抛光理念的新型气囊抛光技术。研究了气囊抛光接触区内磨粒的运动轨迹、压力分布和抛光力的分布情况,建立了气囊抛光接触区内磨粒的运动模型、压力模型,揭示了气囊抛光接触区内磨粒直径对抛光力和被加工工件内部剪切应力的影响规律,研究了抛光过程中工件内部的剪切应力分布,明确了材料疲劳去除机理。为气囊抛光的应用奠定了理论基础。     

离心泵内部流场的模拟

随着水泵叶轮的高速旋转，其内部的流体产生的是一种随机的三维有旋流动，这种流场的特性很难掌握。特别是在加速阶段，内部流体的复杂运动对外部特性的影响表现的更加明显，通过采用Fluent软件对离心泵的内部流场进行模拟，旨在发现水泵内部流体的运动特点。     

基于Fluent的双组份打胶机胶体流动的数值模拟

以双组份打胶机的胶体流动管路为研究对象,用UG软件建立了其内部流场的三维模型,采用CFD软件Fluent对其内部复杂流动进行了三维数值模拟,并对流体经过SK型静态混合器后的压力降的理论值与模拟值进行比较,两者是吻合的.     

复杂曲面软性磨粒流抛光可行性研究

提出基于软性磨粒流的复杂曲面与约束模块相配合的高精密抛光加工方法。使磨料高速高压通过经过设计的流道,利用液固两相软性磨粒流中磨粒的微量切削力加工复杂曲面,从而克服复杂曲面直接接触抛光的困难。以计算流体力学(CFD)的理论作为进行流体仿真的理论基础。建立了复杂曲面与约束模块组成的流道三维模型。通过前处理软件ICEM CFD画出三维模型的网格。将网格文件导入流体分析软件FLUENT。在FLUENT中采取Mixtrue两相流和k-ε湍流模型对涡轮整体叶盘的磨粒流抛光进行流场的三维数值模拟,获得流场中磨料的流动模式。主要对不同压力差下流场的压力场和湍流动能进行分析,得到出入口压强差对磨料的流动细节和特性的影响,从而达到对流场进行分析的目的。     

锥面镜磁流变抛光去除函数畸变规律分析与演绎

磁流变抛光是实现锥镜低表面损伤、面形误差高效抑制的重要工艺，然而锥面磁流变抛光去除函数畸变严重、畸变规律复杂，而现有方法难以直接有效建立其去除函数模型，导致面形收敛效率低下。本文分析了锥面曲率效应对磁流变抛光去除函数畸变的影响机制，研究去除函数的基准化特征参数关于平均曲率的解析规律，建立了由平面到锥面的磁流变抛光去除函数演绎方法。该方法将锥面去除函数的长宽、体去除率、峰去除率演变规律综合纳入到演绎之中，更全面地反映了锥面曲率效应下的磁流变抛光去除函数的畸变特性，同时避免了理化特性参数测量以及复杂方程和非线性问题的求解，为实际工况下锥面去除函数演绎提供一种有效、低成本方法。重复性采斑实验结果显示锥面去除函数特征参数的演绎误差为3.20%～12.02%，证明了该演绎方法具有较强的适用性。     

高速离心泵内部流动数值计算结果研究

利用三维κ-ε双模型方程对一种高速泵的内部流动规律进行了研究，计算了从进口到出口的整个流场，得到了其内部流动的主要特征，为了解高速泵内部流动规律提供了重要的理论依据。     

固液两相磨粒流研抛工艺优化及质量影响

为研究磨粒流对异形腔孔内壁表面以及微小孔的研抛去毛刺等的作用效果,探讨了研抛过程中磨粒流各工艺参数与加工质量间的作用关系。以共轨管这种非直线管为研究对象,对磨粒流抛光共轨管过程进行数值模拟研究,探索各工艺参数对磨粒流研抛的影响。数值模拟结果表明:控制碳化硅体积分数可以改变磨粒流研抛过程中的粘温特性,从而可以控制磨粒流的研抛质量。然后采用正交方法设计实验方案,实验过程中,采集抛光过程中温度和粘度的变化数据,分析磨粒流研抛中粘温特性对磨粒流研抛质量的影响。试验与数值模拟结果表明,在磨粒流研抛共轨管过程中SiC的体积分数比出口压力的极差秩大,磨粒流研抛确实可有效改善工件表面质量。而且本文还进一步得出在本试验条件下,磨粒流研抛共轨管的最佳工艺参数:出口压力为5 MPa,SiC体积分数为0.25%,SiC目数为80,同时获得了表面粗糙度与体积分数的回归方程,可用于指导磨粒流实际研抛生产工作。     

介电泳效应磨粒流抛光中的电极形态

针对薄壁陶瓷工件内表面抛光，提出一种基于介电泳效应的磨粒流抛光方法。将非均匀电场布置于陶瓷工件外表面，极化磨粒，实现陶瓷工件内表面高效抛光。仿真分析发现:电极间隙比为2时，SiC磨粒具有最好的介电泳效应，参与抛光的磨粒最多。陶瓷工件初始内表面粗糙度值Ra为(208±5)nm时，抛光10 h后，无介电泳效应的磨粒流抛光工件内表面粗糙度值Ra为51 nm，有介电泳效应的磨粒流抛光工件内表面粗糙度值Ra为23 nm。     

Electrolytic Plasma Surface Polishing of Complex Components Produced by Selective Laser Melting

The applicability of electrolytic plasma surface polishing to complex components produced by selective laser melting (SLM) is analyzed. By electrolytic plasma polishing by electrolyte spraying, the surface quality of components produced by SLM may be improved. This technology is found to decrease the surface roughness from R_a = 5.6 μm to 1.4 μm. The optimal pressure of the electrolyte jet is 0.02–0.05 MPa. At high pressures, the process becomes unstable. By electrolytic plasma polishing on the basis of electrolyte jets, uniform external and internal surface roughness of components produced by SLM may be ensured.     

Simulation-based approach to modeling the chip formation energy of polishing process

Polishing is one typical material removal process, which is widely used for surface processing of porcelain tiles. Due to complex polishing head structure and kinematics features of polishing machine, polishing for porcelain tile is a high energy intensity process. To improve the energy efficiency by optimizing operation, it is essential to establish an energy consumption model for polishing process. This article divides the total energy of polishing process into constant energy and chip formation energy. Furthermore, this article focuses on modeling the chip formation energy for optimizing operation. Based on the energy conversion mechanism and energy flow characteristics, the chip formation energy of polishing process is further divided into three motion energies that govern the abrasive trajectory over the tile surface. A conceptual framework of simulation-based approach is then proposed for modeling chip formation energy of polishing process by integrating the above calculation algorithm of motion energy. Finally, a case study is implemented to illustrate the validation of the proposed approach, and the results show that it is a feasible tool to model the chip formation energy of polishing process and reveal the influence of different process operational parameters.     

纳米胶体自激脉冲空化射流抛光技术

为了满足光学复杂曲面的精密、高效加工,提出一种利用空化效应促进射流加工效率的光学表面加工方法——纳米胶体自激脉冲空化射流抛光,并研制了加工系统。采用流体动力学对纳米胶体自激脉冲空化射流抛光中的喷射过程进行了仿真,获得了周期为0.3s的自激脉冲射流典型时刻下加工流场的流体动、静压力、速度、空化效应分布规律。进行了纳米胶体自激脉冲空化射流抛光试验,结果表明该系统能够产生效果良好的自激脉冲空化射流。采用该方法对单晶硅表面进行加工可以得到表面粗糙度为Ra0.904nm(Rms1.225nm)的超光滑表面,此加工表面粗糙度质量与相同加工条件下的普通纳米胶体射流抛光相当,但其加工效率较普通纳米胶体射流抛光能够提升20%左右,能够满足光学表面高效精密加工的需要。     

A novel polishing method for single-crystal silicon using the cavitation rotary abrasive flow

Traditional low-pressure abrasive flow polishing can produce highly smooth surfaces, but the efficiency of this method is too low for polishing of hard-brittle materials parts. This paper proposes a novel cavitation rotary abrasive flow polishing (CRAFP) method. The energy generated from the cavitation bubble collapse is used to increase the kinetic energy of the abrasive particles in the low-pressure abrasive flow and the motion randomness of the abrasive particles near the wall; thereby, the efficiency and quality of low-pressure abrasive flow polishing are improved. The CRAFP mechanism was first introduced, and then the characteristics of the CRAFP process were investigated using computational fluid dynamics (CFD)-based abrasive flow simulation. Subsequently, a single-crystal silicon wafer polishing test was carried outperformed to verify the validity of the CRAFP method. The polishing results were compared with those of the traditional low-pressure abrasive flow polishing method. After 8 h of polishing using the CRAFP method and the traditional low-pressure abrasive flow polishing method, the surface roughness of the workpiece decreased to7.87 nm and 10.53 nm, respectively. Furthermore, by starting at similar initial roughness values, the polishing time required to reduce the roughness to 12 nm was 3.5 h and 6 h, respectively. The experimental results demonstrated that CRAFP can satisfy the surface requirements of single-crystal silicon (R_a < 12 nm) and exhibit high polishing efficiency and good quality.     

Study on the manufacturing process controlling for aspheric surface ballonet polishing

Ballonet polishing tools, soft gasbags filled with compressed gas, have already been one of the most reliable tools in curved surface polishing due to their adaptability to change their shape to fit the worked surfaces with the same contact stress everywhere. When the internal pressure of the gasbag is adjusted on-line, the contact stress could be controlled as you want. But, because of the tensile stress of the gasbag's material, the internal pressure could not identify the real contact condition anymore. In this paper, the contact force is used to identify the real contact condition for workpieces of aspheric surfaces which is indispensable to the polishing process control. Based on the measured internal pressure of the gasbag and the on-line-controlled contact force in the normal direction, this paper studies the arithmetic of the contact area for aspheric surfaces, finds a way to eliminate the great difference of machining speed, and advances an arithmetic of the machining time for material removal controlling in the process of aspheric surface ballonet polishing. A real ballonet polishing system is developed for aspheric surfaces, and experiments show that it is a better way by controlling the contact force rather than by controlling the internal pressure in the process of aspheric surface ballonet polishing.     

叶序结构抛光垫表面的抛光液流场分析

为了解决在化学机械抛光过程中抛光接触区域内抛光液的分布均匀性问题,基于生物学的叶序理论,设计葵花籽粒结构的仿生抛光垫,建市化学机械抛光抛光液流场的运动方程和边界条件,利用流体力学软件(Fluent)对抛光液的流动状态进行仿真,并获得叶序参数对抛光液流动状态的影响规律.结果表明:抛光液在基于葵花籽粒的仿生抛光垫的流动是均匀的,抛光液沿着逆时针和顺时针叶列斜线沟槽流动,有利于流体向四周发散.     

耦合超声场的气液固三相磨粒流多物理场数值模拟研究

针对气液固三相磨粒流抛光研究中流场分布不均问题,对气液固三相磨粒流中的湍流分布、湍流峰值分布、能量分布、温度分布和加工质量等方面进行了研究,对气液固三相磨粒流的抛光方法和抛光问题进行了归纳,提出了一种耦合超声场的气液固三相磨粒多物理场数值模拟方法,利用超声场的交变声压增加了气液固三相磨粒流流场的扰动,改变了流场分布。研究结果表明:不同的超声频率和声压幅值会带来不同的流场分布,其中频率为20 k Hz、声压幅值为30 k Pa的超声场所得的流场分布最优。该研究成果对气液固三相磨粒流抛光方法的推广与实际运用具有重要意义。