基于CAD/CAE/CAM/RP的复杂陶瓷产品快速制造技术

针对目前手工方式的卫生洁具等复杂陶瓷产品的研发过程,借鉴CAD/CAE/CAM/RP技术在其它制造行业中应用的成功经验,将这些先进制造技术应用于卫生洁具等复杂陶瓷产品的研发中;CAD用于设计产品和模具的模型,CAE用于模拟洁具冲水过程和分析冲水性能,RP用于制作洁具产品的原型,CAM用于加工试用石膏工作模具。就这些技术的应用提出了两种主要方案,并分析了各自的特点。经过实际应用表明:先进制造技术的应用能大大缩短产品研发周期、提高产品质量、降低开发成本。     

我国注塑模具CAD／CAE／CAM技术的研究与应用

文章介绍了近几年来国内注塑模具CAD/CAE/CAM技术研究已取得的成果,评价了国内自行开发的注塑模具CAD/CAE/CAM水平与各个方面的研究进展以及在引进工作中存在的问题,提出了注塑模具CAD/CAE/CAM技术研究与应用的方向及开发战略。     

CAD/CAE/CAM软件技术在塑料工业中的应用研究

计算机辅助设计(CAD)/计算机辅助工程(CAE)/计算机辅助生产(CAM)软件技术是当代塑料工业生产的重要辅助工具,用于塑料加工中模具的设计和制造、成型工艺优化和参数确定等方面,可有效提高塑料制品的生产效率和产品合格率.详述了CAD/CAE/CAM软件技术在塑料工业中的应用研究。     

基于并行工程的中空吹塑模集成系统研究

针对采用传统的串行模式进行中空吹塑模具设计和制造中存在的问题,提出基于并行工程的中空吹塑模集成系统流程,使其贯穿于中空吹塑成型的共性机理研究、制品设计、模具设计与制造和试模的全过程,并讨论制品设计与模具CAD/CAE/CAM的并行设计、中空吹塑产品的特征建模、中空吹塑模CAD/CAE/CAM知识和规则处理机制等关键技术。     

CAD/CAE/CAM在注塑模设计中的应用

详细介绍了基于Pro/E软件的注塑模设计,利用Moldflow软件进行注塑分析模拟,并在MasterCAM软件中进行模具的模拟加工和数控编程,将三者集合成一个完整的注塑模CAD/CAE/CAM系统,为注塑模具设计制造提供有效的途径。     

基于Pro/E的注塑模CAD/CAE/CAM集成化技术

介绍了模具CAD／CAE／CAM集成化技术的产生与发展趋势，指出了基于Pro／E软件的注塑模CAD／CAE／CAM集成化技术的特点和系统结构，分别分析了模具CAD／CAE／CAM集成化技术在注塑模设计阶段、分析阶段和制造阶段的应用过程，阐述了其对缩短制造周期、降低模具成本、提高制品质量的积极意义。     

基于CAD/CAE/CAM技术的电话机注塑模设计

介绍了Pro/E在注射模具设计中的应用和基于Moldflow软件的注射成型分析以及在UG环境下的CAM模拟。通过实例阐述了采用CAD/CAE/CAM技术进行电话机注塑模的设计和分析过程,并运用UG软件对该零件型腔进行了加工刀路设计,模拟了数控加工过程。采用CAD/CAE/CAM技术可以缩短产品的开发周期,提高设计质量。     

注塑模设计和制造中的CAD／CAM／CAE技术

论述了注塑模设计和制造CAD、CAM、CAE系统的特点、原理和方法以及它们的集成技术，指出了注塑模CAD/CAM/CAE技术的发展方向。     

CAE/CAD技术在塑料模具设计中的应用

在塑料加工模具设计和制造的应用中,CAE技术可以进行模具浇注系统和冷却系统分析,可以应用于辅助模型设计和可视化仿真。主要介绍了塑料模具设计和加工的发展现状以及CAE/CAD软件开发及仿真技术和仿真系统开发的发展现状。并指出CAE/CAD仿真技术与Pro/E软件和Moldfl ow软件相结合,在塑料模具设计和生产领域具有十分广泛的应用前景,其可以大大缩短产品开发周期,提高产品设计质量。     

CAD/CAE技术在汽车模具中的应用进展

简述了注塑模具CAD/CAE软件在汽车模具加工设计中的应用及其优点。与传统技术相比,CAD/CAE软件可以节省设计成本,缩短模具设计时间,并为设计人员提供有力的技术支持与解决方案。     

EVA/EPDM/IR/IR共混发泡材料的性能研究

研究了乙烯醋酸乙烯酯共聚物（ＥＶＡ）／ＥＰＤＭ／ＩＲ三元共混和ＥＶＡ／ＥＰＤＭ／ＩＲ／ＩＲ四元共混发泡材料的性能。在ＥＶＡ中混入ＥＰＤＭ可使发泡材料的拉伸强度、撕裂强度和粘合强度提高,而收缩率和压缩永久变形降低;在ＥＶＡ中混入ＩＲ除具备混入ＥＰＤＭ同样的优点外,还可提高发泡材料的柔性;ＩＲ的混入可改善发泡材料二次热压成型制品的表面清晰度。     

Microwave Dielectric Properties of CaTiO3-CaAl1/2Nb1/2O3 Ceramics Doped with Li3NbO4

The microwave dielectric properties of CaTi_{1− x} (Al_1/2Nb_1/2) _x O₃ solid solutions (0.3 ≤ x ≤ 0.7) have been investigated. The sintered samples had perovskite structures similar to CaTiO₃. The substitution of Ti⁴⁺ by Al³⁺/Nb⁵⁺ improved the quality factor Q of the sintered specimens. A small addition of Li₃NbO₄ (about 1 wt%) was found to be very effective for lowering sintering temperature of ceramics from 1450–1500° to 1300°C. The composition with x = 0.5 sintered at 1300°C for 5 h revealed excellent dielectric properties, namely, a dielectric constant (ɛ_r) of 48, a Q × f value of 32 100 GHz, and a temperature coefficient of the resonant frequency (τ_f) of −2 ppm/K. Li₃NbO₄ as a sintering additive had no harmful influence on τ_f of ceramics.     

Effect of V2O5 Doping on the Sintering and Dielectric Properties of M-Phase Li1+x−yNb1−x−3yTix+4yO3 Ceramics

The effect of the addition of V₂O₅ on the structure, sintering and dielectric properties of M -phase (Li_{1+ x − y} Nb_{1− x −3 y} Ti _x +4 _y )O₃ ceramics has been investigated. Homogeneous substitution of V⁵⁺ for Nb⁵⁺ was obtained in LiNb_{0.6(1− x )}V_{0.6 x} Ti_0.5O₃ for x ≤ 0.02. The addition of V₂O₅ led to a large reduction in the sintering temperature and samples with x = 0.02 could be fully densified at 900°C. The substitution of vanadia had a relatively minor adverse effect on the microwave dielectric properties of the M -phase system and the x = 0.02 ceramics had [alt epsilon]_r= 66, Q × f = 3800 at 5.6 GHz, and τ_f= 11 ppm/°C. Preliminary investigations suggest that silver metallization does not diffuse into the V₂O₅-doped M -phase ceramics at 900°C, making these materials potential candidates for low-temperature cofired ceramic (LTCC) applications.     

SO42-/MxOy型固体超强酸研究进展

SO₄^2-/M_xO_y固体超强酸具有不腐蚀设备、污染小、耐高温、对水稳定性好和可重复使用等优点。综述了SO₄^2-/M_xO_y型固体超强酸的催化机理、失活原因、改性及表征方法,并对今后SO₄^2-/M_xO_y型固体超强酸的研究方向进行了展望。     

Ferromagnetism and Magnetoresistance in La0.67Sr0.33Fe0.07Mn0.93O3

A bulk ceramic sample La_0.67Sr_0.33Fe_0.07Mn_0.93O₃ (LSFMO) with a rhombohedral structure has been prepared from a coprecipitated carbonate precursor in this study. Ferromagnetism and a negative, isotropic magnetoresistance (MR) as large as 11% have been observed in a ceramic sample of LSFMO. There are two resistivity transition peaks on the resistivity versus temperature curves. The resistivity peak and MR have been related to the ferromagnetic state in LSFMO.     

A- and B Site Cosubstituted Ba6−3xSm8+2xTi18O54Microwave Dielectric Ceramics

Tin (Sn) substitution into the B-site and Nd/Sn cosubstitution into the A- and B-sites were investigated in a Ba _{6−3 x} Sm_{8+2 x} Ti₁₈O₅₄solid solution ( x = 2/3). A small amount of tin substitution for titanium improved the temperature coefficient of resonant frequency (τ_f) but led to a decrease of the relative dielectric constant (ɛ) and the quality factor ( Qf ). The Ba_{6−3 x} Sm_{8+2 x} (Ti_{1− z} Sn_z)₁₈O₅₄-based tungsten-bronze phase became unstable for compositions with a tin content of ≥10 mol%, where BaSm₂O₄and Sm₂(Sn,Ti)₂O₇appeared, and finally, these phases became the major phases. On the other hand, Nd/Sn cosubstitution led to a good combination of high ɛ, high Qf , and near-zero τ_f. Excellent microwave dielectric properties were achieved in Ba_{6−3 x} (Sm_{1− y} Nd _y )_{8+2 x} (Ti_{1− z} Sn _z )₁₈O₅₄ceramics with y = 0.8 and z = 0.05 sintered at 1360°C for 3 h: ɛ= 82, Qf = 10 000 GHz, and calculated τ_f=+17 ppm/°C. The tolerance factor and electronegativity difference exhibited important effects on the microwave dielectric properties, especially the Qf value. A large tolerance factor and high electronegativity difference generally led to a higher Qf value.     

Relaxor Behavior of the 0.9BaTiO3–0.1La(Mg1/2Ti1/2)O3 Solid Solution

Low-frequency dielectric response of air- and oxygen-sintered ceramics with the composition 0.9BaTiO₃–0.1La(Mg_1/2Ti_1/2) O₃ (0.9BT–0.1LMT) has been studied in the temperature range of 12–550 K. In comparison with pure BT, in 0.9BT–0.1LMT the dielectric permittivity maximum is shifted by almost 300 K toward lower temperatures. Both real and imaginary parts of dielectric permittivity of the solid solution, in the range 12–150 K, show a strong frequency-dependent behavior, which is typical of relaxors. On the basis of the model of exponential cluster size distribution and the Cole–Cole equation, the degree of interaction between the polar clusters was estimated. It was shown that the oxygen vacancies arising during sintering at high temperatures did not affect noticeably the relaxor properties of the material. The role of heterovalent La³⁺/Ba²⁺ and Mg²⁺/Ti⁴⁺ substitutions in the relaxor behavior formation is discussed.     

Electronic Structure and Bonding in Crystalline Y10[SiO4]6N2

The electronic structure and bonding of the complex ceramic crystal Y₁₀[SiO₄]₆N₂ is studied by a first-principles method. It is shown that this crystal is an insulator with a direct band gap of 1.3 eV. It has some unique properties related to the one-dimensional chain structure in the c -direction and the planar N-Y bonding in the x - y plane.     

Effect of Nb2O5/ZnO Addition on Microwave Properties of (Zr0.8Sn0.2)TiO4 Ceramics

The effects of Nb₂O₅ and ZnO addition on the dielectric properties, especially the quality factor, of (Zr_0.8Sn_0.2)TiO₄ (ZST) ceramics were investigated in terms of the sintered density acquired by the zinc. For ZST ceramics with 2 mol% added ZnO, the relative density of the samples decreased with >0.5 mol% addition of Nb₂O₅. On the other hand, for samples with 6 mol% added ZnO, the relative density remained >97%, even when the amount of Nb₂O₅ was increased to 2.0 mol%. When >0.5 mol% Nb₂O₅ was added, both the quality factor and the dielectric constant exhibited similar trends with sintered density. The ZST ceramics with 6 mol% added ZnO, especially, still manifested a quality factor >40 000 and a dielectric constant of 37, even when the amount of Nb₂O₅ was increased, values that are not explainable by the previously suggested electronic defect model.     

Microstructure and Microwave Dielectric Properties of Ba(Zn1/3Ta2/3)O3 Ceramics with ZrO2 Addition

The effect of ZrO₂ on crystallographic order, microstructure, and microwave dielectric properties of Ba(Zn_1/3Ta_2/3)O₃ (BZT) ceramics was investigated. A small amount of ZrO₂ disturbed the 1:2 cation ordering. The average grain size of the BZT significantly increased with the addition of ZrO₂, which was attributed to liquid-phase formation. The relative density increased with the addition of a small amount of ZrO₂, but it decreased when the ZrO₂ content was increased. Variation of the dielectric constant with ZrO₂ addition ranged between 27 and 30, and the temperature coefficient of resonant frequency increased abruptly as the ZrO₂ amount exceeded 2.0 mol%. The Q value of the BZT significantly improved with the addition of ZrO₂, which could be explained by the increased relative density and grain size. The maximum Q × f value achieved in this investigation was ∼164 000 GHz for the BZT with 2.0 mol% ZrO₂ sintered at 1550°C for 10 h.