汽车覆盖件模具的非球头刀宽行加工方法

汽车覆盖件模具型面一般是由大面积平坦面和一定陡立面结合的构成的自由曲面.针对汽车覆盖件模具粗加工及半精加工中球头刀效率低的问题,将非球头刀的宽行加工应用于汽车覆盖件模具粗加工与半精加工过程,在工艺上使用环形刀加工陡立面,高进给铣刀加工平坦面的组合加工方式来代替普通球头刀加工,论述了高进给铣刀在加工平坦类曲面中的优势,提出了平底类刀具铣削平坦凹曲面的最小曲率半径判定原则,并对环形刀和高进给铣刀铣削区域内的刀路轨迹进行优化.最后,在三轴数控机床上进行了实验验证,实验结果表明:宽行加工工艺与球头刀加工相比可提高加工效率44.75%.     

基于TSP的孔群加工路径优化算法

建立以孔群加工最短路径为优化目标的数学模型,采用蚁群算法与2-OPT算法相融合的优化方法,研究了模具顶针板孔群加工刀具路径优化问题.结果表明,该融合算法加快了收敛速度,可有效避免陷入局部最优解,加工优化路径比贪心算法缩短12.34%,比基本蚁群算法缩短14.78%,即有效缩短了加工路径,减少了空走刀时间,提高了数控加工效率.     

微电火花加工中探针与工件中铁元素作用机理研究

以加工工件中铁原子为基组构成基本模型,通过理论计算和模拟研究了铁元素在分别外加面电极和体电极情况下,整个系统的电子传输过程与电子态密度的分布.结果显示在外加体电极时,相比于加面电极时的情况,其电子穿过体系的概率更大,有利于整个系统的电子传输,对电火花加工更有利.另外还得出了两个传输系统的能级和能隙,能量对比显示,在外加体电极时,分子失去电子的能力比加面电极强,且更加容易发生跃迁,整个体系的加工性更好.考虑实际加工过程,对电极和工件间距离变化时系统的电子传输和态密度的变化进行了研究,结果显示,钨面电极在距离为0.48 nm时,电火花加工处于截止状态,而钨体电极则是在距离为0.58 nm时,电火花加工截止.     

ADAMS二次开发技术在非圆斜齿轮齿廓面设计中的应用

依据齿条刀具范成法加工非圆齿轮的原理,建立了计算机仿真加工非圆斜齿轮的滚切数学模型,提出了一种基于ADAMS二次开发技术生成非圆斜齿轮齿廓面的方法,并开发了非圆斜齿轮仿真加工软件,用该软件生成的椭圆斜齿轮,已成功应用于椭圆斜齿轮行星系宽窄行分插机构中,验证了该方法的正确性。     

叠层材料变参数振动钻削模型与实验研究

简述了叠层材料的特点及其应用,分析了叠层材料的结构特点,提出了接合区和泛接合区的概念。在此基础上建立了叠层材料变参数振动钻削的加工模型,给出了３层叠层材料５区段变参数振动钻削加工方案。多种叠层材料的加工实验表明,采用变参数振动钻削工艺可明显改善加工指标,是合理有效的工艺方法。     

摆动活齿齿轮传动的中心轮齿形加工原理及方法

根据摆动活齿齿轮传动原理，设计出在Ｙ５４插齿机上展成加工中心轮齿形的加工方法，为普及和推广摆动活齿齿轮传动创造了有利条件．     

转向蜗杆的等间距法编程

为变螺距，变直径的向蜗杆在加工中心上的加工提供了一种实可行的编程方法和加工程序，为提高进口零件的国产化率作了贡献，具有普遍的推广价值。     

Influence of alumina content to mechanical properties and electric discharge machinability of zirconia (1.5Y-1.5Nd-TZP)-tungsten carbide-alumina composites

Composites of yttria neodymia co-stabilized zirconia, 24–32 vol% nanoscale tungsten carbide and 0.5–10 vol% alumina were manufactured by hot pressing and characterized in terms of mechanical properties, phase composition, microstructure and electric discharge machinability. Addition of 10 vol% alumina leads to an increase in hardness and Young’s modulus and an in average slightly higher bending strength. The transformability of the zirconia matrix and thereby fracture toughness is reduced by alumina addition. In EDM alumina reduces the thickness of the re-solidified layer, reduces surface defects and leads to smoother surfaces especially at high discharge currents, the effect on material removal rate is negligible.     

Progress in non-traditional machining of amorphous alloys

Amorphous alloys are a new type of multi-functional advanced material with the properties of general metal materials and glass, which are also called metallic glasses. They have good comprehensive properties, such as a wide application range, low cost, and high reusability. Using reasonable process parameters, non-traditional machining can not only realize the machining of complex amorphous parts, but also avoid the crystallization and oxidation of amorphous alloys, realizing tasks that cannot be accomplished by traditional machining. Therefore, this review systematically summarizes the research status and development potential of amorphous alloys fabricated using non-traditional machining methods. First, we introduce the principles of laser machining, ultrasonic machining, electrical discharge machining, electrochemical machining, and other non-traditional machining methods for amorphous alloys. Subsequently, the influence of the machining parameters and other external conditions on the machining effect is summarized. The machining cost, machining efficiency, and environmental impact of these non-traditional machining methods were compared. Finally, non-traditional machining technology for amorphous alloys is summarized and discussed.     

Alumina dissolution process to fabricate bimodal pore architecture alumina with superior green and sintered properties

Herein, a straightforward, adaptable, and cost-effective approach has been proposed to realize the concept of dissolution of alumina in acidic aqueous media to fabricate porous alumina showing exceptional green machining properties and exhibiting good thermomechanical properties through in situ generated blowing agents and thermo-foaming process. The process involves dissolving alumina in concentrated sulfuric acid to generate aluminum hydroxide and aluminum sulfate, which act as blowing agents to produce pores in the final structure through a decomposition process at elevated temperatures. By varying the concentration of deionized water and acidification using sulfuric acid, different alumina slurries are prepared. Sintering shrinkage is well countered through simultaneous consolidation and decomposition process during the heat treatment, and a minimum shrinkage of 0.88% is achieved. In addition to its pore-forming properties, aluminum sulfate also provides strong binding effects to green bodies, contributing to their exceptional green machining properties. The resulting porous alumina exhibits a green flexural strength of up to 17 MPa, making it capable of bearing loads and forces during green machining. The sintered porous alumina fabricated in the study has a porosity range of 34.43%–59.24% and a flexural strength of 27.84–53.21 MPa. The prepared porous alumina also exhibits satisfactory thermal resistivity, with a minimum thermal conductivity of 1.23 W/m K, and has intra/intergranular space in the nano range. The coexistence of a combination of bimodal pores in a single monolithic matrix makes it exceptionally porous and suitable for an extensive spectrum of applications.