CA6140/BQ无级变速车床主传动系统设计

详细论述了无级变速主传动系统设计和PLC控制程序设计,变频器在CA6140/BQ无级变速切削车床中的控制方式、参数设置及与主传动系统的连接,最后结合实例应用阐明了无级变速车削方法对提高零件表面加工质量的意义。     

机车质量动态预防性管理系统的技术措施

为满足我国＂高铁＂发展的要求,创建先进的机车行车质量动态管理系统,将质量管理提高到适时、准确、快捷、预防型管理水平,做到＂五要、两减少＂,以便及时发现机车机故隐患、迅速进行预防性修理、减少机故、减少临修,达到无隐患按时出库和无故障高速运行。所以需要探讨其相应的技术措施,促进其尽早实现。     

Out-of-plane shearing characteristics of coated paperboard

The out-of-plane shearing characteristics of a paperboard by a straight punch and dies are important to estimate the paperboard stripping performance. In this paper, in order to reveal the die clearance effect and the feed velocity effect on the sheared end-profile of the paperboard, a precision shear testing device was developed. The shear cutting of the paperboards was experimentally carried out by varying the die clearance and the feed velocity of punch. Through this work, it was confirmed that (1) the load response had two kinds of transition gradient before passing through the maximum load point; (2) the shearing performance was classified with the normalized indentation depth d/t=0.1∼0.2 into an out-of-plane shear mode and a combined shear mode. Here, the combined mode was composed of out-of-plane bending and in-plane tensile deformation; (3) the surface layers of paperboard were observed with a de-lamimated state using an image processing of side-view flow deformation of the paperboard. Furthermore, (4) the shear strength was discussed with the orthotropic properties of the paperboard.     

Electrical energy metering: Some challenges of the European Directive on Measuring Instruments (MID)

The introduction of static electric energy meter together with voltage and current distortions in the electric networks are revolutionizing the measurement of the electrical energy. Several questions and studies are proposed in the scientific literature concerning with metrological and reliability aspects of the actual electrical energy measurement. The European Directive on Measuring Instruments (MID) represents a different spin on setting the performance and safety requirements for those meters. The International Organization of Legal Metrology (OIML) has published the document D11 discussing recommendations for legislation to meet the MID. An OIML technical committee is drafting the recommendation (IR46) that would give regulatory bodies an easily-adoptable set of requirements and tests to meet the requirements of the MID. With the introduction of the MID directive, the actual discussion involves aspects as the metrological characterization of the meters. The paper proposes an analysis of the test settings imposed by the actual MID-harmonized standards, regarding the electric energy metering. The aim is to check the presence of degree of freedom in the test settings that could compromise both result reliability and the compliance/non-compliance of a given apparatus.     

Film Thickness of Mechanically Worked Lubricating Grease at Very Low Speeds

Several different types of commercially available greases, aged in a roll stability tester, have been tested in a ball-on-disc machine where the film thickness was measured using the interferometry method. The grease film thickness at very low speed is thicker than the base oil film thickness due to the contribution of the thickener in this regime, which practically vanishes at higher speeds. The (mechanical) aging process reduces the thickener material, decreasing the grease film thickness at very low speeds (entrainment speed less than 0.01 m/s) with aging time, whereas no significant difference was found at higher speeds where the grease film thickness still approached the calculated base oil film thickness.     

INFLUENCE OF MATERIAL REMOVAL ON THE DYNAMIC BEHAVIOR OF THIN-WALLED STRUCTURES IN PERIPHERAL MILLING

Machining is a material removal process that alters the dynamic properties during machining operations. The peripheral milling of a thin-walled structure generates vibration of the workpiece and this influences the quality of the machined surface. A reduction of tool life and spindle life can also be experienced when machining is subjected to vibration. In this paper, the linearized stability lobes theory allows us to determine critical and optimal cutting conditions for which vibration is not apparent in the milling of thin-walled workpieces. The evolution of the mechanical parameters of the cutting tool, machine tool and workpiece during the milling operation are not taken into account. The critical and optimal cutting conditions depend on dynamic properties of the workpiece. It is illustrated how the stability lobes theory is used to evaluate the variation of the dynamic properties of the thin-walled workpiece. We use both modal measurement and finite element method to establish a 3D representation of stability lobes. The 3D representation allows us to identify spindle speed values at which the variation of spindle speed is initiated to improve the surface finish of the workpiece.     

多工序车削的自适应搜索非支配排序遗传算法

在实际数控生产加工过程中,切削参数的优化对于保证加工质量、提高生产效率和降低加工成本具有非常重要的意义。为计算以单位生产成本最小为优化目标的多工序车削非线性优化模型,在NSGA-II算法基础上提出了一种新的自适应搜索非支配排序遗传算法(ASNSGA)。多工序车削加工实例结果表明,与模拟退火算法(SA/PA)、分散搜索算法(SS)及浮点编码遗传算法(FEGA)优化算法比较,自适应搜索非支配排序遗传算法得到最低的单位生产成本,有助于数控加工中粗车进给量、粗车切削速度及精车进给量、精车切削速度等切削参数的优化选择。     

硅片切割张力控制策略研究

对硅棒的切片加工技术进行了简介,分析了切割线在走线过程中张力波动产生的原因。提出基于伺服电机转矩控制和张力摆杆相结合的张力控制方案来替代现有的张力重锤控制方案,并建立了该控制方案运动学模型和动力学模型,为张力反馈控制提供了理论依据。通过建立速度控制模式下伺服电机的数学模型,提出模型参考自适应速度同步控制方案与张力摆杆的反馈相结合的张力控制策略。在MATLAB/Simulink仿真环境下分别建立基于PID控制策略和自适应控制策略的张力控制系统仿真模型,仿真结果表明该控制方案明显优于PID控制方案,能够有效控制线速度同步误差和张力波动。     

Spin-Probe Investigations of Head Group Behavior in Aqueous Dispersions of a Nonionic Amphiphilic Compound

Head group behavior of nonionic amphiphilic compound, (poly(oxyethylene) hydrogenated castor oil, HCO), in aqueous dispersions were investigated by EPR (electron paramagnetic resonance) in conjunction with a modern slow-tumbling simulation. The aliphatic spin probes, 5-doxylstearic acid (5-DSA) and 3β-doxyl-5α-cholestane (CHL), were used to obtain fluidity of the surface region of the membrane. The order parameter (S ₀) using the simulation for 5-DSA and CHL in the region were approximately 0.4 and 0.2, respectively. The ordering results suggest that the head group region of the membrane is somewhat fluid. The rotational diffusion coefficients (R _⊥ ≈ 1/(6τ_R)) for the probes were 3.4 × 10⁷ and 7.1 × 10⁷ s⁻¹, respectively. Activation energies, calculated using the temperature dependence of diffusion coefficients, were 18 and 17 kJ/mol for the probes. The EPR results imply that the CHL probe in the HCO membrane has quite different behavior in comparison with that of PC (phosphatidylcholine) from egg. Thus, the present EPR analyses have provided quantitative insight into the surface region of the amphiphilic membrane.     

新流量阀与PLC控制新回路及其应用

在已有液压回路的基础上,提出了一种新的、用于实现动力滑台运动的二工进调速阀的两工进速度换接回路,给出了其组成图和工作原理.采用FX2N-32MR型PLC设计了其控制系统,得出了新回路及其控制系统的特点,展现了PLC在工业控制领域的广阔应用前景.并介绍了新回路在机械加工中的应用.