基于双钻头的孔群加工路径优化算法

引入双钻头对孔群同时加工是提高钻孔效率的有效途径。分析双钻头进行孔群加工的数学模型,通过修改用于单钻头孔群加工路径优化的遗传算法中染色体的表达方式和适应度函数的计算方法,得到基于双钻头的孔群加工路径优化算法。实验结果表明,与单钻头的最优加工路径相比,在不同钻孔速度下使用双钻头同时加工的新算法都能节省近一半的加工时间,有效提高了孔群加工的效率。     

带基准孔的孔群加工路径优化算法

优化孔群加工路径减少刀具移动时间是提高生产效率的有效途径.作者考虑孔群加工中基准孔优先加工的工艺要求,提出了用于带基准孔群加工路径优化的遗传算法.将加工路径优化问题转化为带基准孔优先加工约束的旅行商问题,通过改进适应度计算使得所有染色体都对应满足约束条件的加工路径.实验结果表明,新方法在基准孔优先加工的前提下与最短路径相比仅增加了4.44%的路径长度,在保证孔加工定位精度的同时优化了孔群加工路径.     

基于遗传蚁群混合算法的孔群加工路径优化

为了提高孔群的数控加工效率,以孔群加工路径最短为目标函数,采用遗传蚁群混合算法对孔群加工路径规划问题进行研究。该混合优化算法的前期采用遗传算法、后期采用蚁群算法。在遗传算法向蚁群算法转换过程中,提出一种GSA遗传解到信息素转化策略。该策略以在遗传解endpop中选取前90%个个体和再随机产生的10%个个体合并后组成的新矩阵作为信息素值的转化依据;同时探讨了遗传算法中遗传算子的最佳组合问题。实例计算结果表明:与传统分批按编号加工的路径相比较,采用最佳组合算子和GSA转化策略后的遗传蚁群混合算法求解问题所获得的孔群加工路径缩短了70.9%,比单一遗传算法具有更高的求解精度,理论上可以明显地提高孔群的数控加工效率。     

基于动态规划算法的孔群加工路线优化

孔群加工路线优化,对于提高多孔类零件的加工效率和质量具有重要意义。通过数控机床上孔群加工工艺路线的分析,利用动态规划算法,对数控机床孔群加工路线进行了优化计算。最后通过实例验证此优化方法在孔群加工中明显提高了数控加工的效率、降低了加工成本。     

基于Hopfield算法的孔群加工路径规划

采用改进Hofield方法结合孔群加工的最优化目标函数进行钻削加工中心路径的优化，在孔群加工，总加工成本由刀具成本，加工成本，非生产刀具行进时间，刀具换刀且成。因此，由于刀具行进路线需要规划，可以看出该优化类似于TSP问题，提供一个基于改进Hofield方法的解决程序，进行路径优化。上述问题的决策可以根据提出算法的输出作出。由计算试验得到结果显示，总加工成本可以合理的搜索时间内大幅度减少。     

HDI板孔群的K-means聚类及加工路径优化研究

电路板的激光打孔路径优化是一个NP完全问题,随着孔群数量的增加,其复杂性和解空间会成指数性增长。文章采用K-means算法和改进模拟退火算法,并结合孔群加工的数学模型研究HDI激光打孔的路径优化。首先采用K-means算法聚类分析得到相似度高的孔群,初始种群运用贪婪选择策略,降低起始搜索范围,提高收敛效率;寻优过程中加入遗传算法的DIM(Displaced Inversion Mutation)变异算子,避免模拟退火算法陷入局部最优解。仿真试验结果表明,该方案求解出的最优路径比采用模拟退火算法有明显改善。     

基于改进遗传算法的孔群数控加工路径优化

针对孔群加工路径优化中遗传算法存在的局部最优和收敛速度慢等问题,提出采用模拟退火算法改进遗传算法进行路径优化。首先根据孔群数控加工的特点建立数学模型,采用遗传算法设计种群编码,建立适应度函数选择优秀种群,并对保留的优秀种群进行交叉、变异等操作,实现种群进化,其次引入模拟退火算法对其适应度函数进行拉伸处理,调整种群进化差异性而加速寻优进度,同时采用改进的Metropolis准则调整接受概率,调节旧种群和新种群的进化程度,增强遗传算法的全局搜索能力。实例表明:改进算法用于某模具的孔群加工,有效克服遗传算法的早熟现象,缩短收敛次数,平均路径缩短比例达6.9%,提高了加工效率,效果良好。     

电火花线切割加工工艺参数的多目标优化

运用多目标优化方法研究确定电火花线切割加工工艺参数,建立了多目标优化的数学模型,对其求解方法进行了探讨,并给出了一个应用实例。     

电火花线切割加工工艺参数的多目标优化

运用多目标优化方法研究确定电火花线切割加工工艺参数 ,建立了多目标优化的数学模型 ,对其求解方法进行了探讨 ,并给出了一个应用实例     

网阵孔群加工的刀具路径设计

探讨刀具路径对数控加工的影响，基于消除反向间隙的原则，设计网阵孔群加工的刀具路径，以提高孔加工精度，并设计出相应孔群加工的用户宏程序。     

型腔加工中的行切方向的优化方法

采用数学优化的方法来优化行切加工轨迹的方向，用此方法生成的刀具轨迹是满足既定目标的最优行切刀轨。概括了型腔加工轨迹生成的方法，分析了采用数学优化的方法来优化行切加工轨迹方向的原理、过程，并给出了相应的程序框图。     

基于Cimatron软件的模具定位孔加工

在分析Cimatron常用的几种定位孔加工方法的基础上,探索出了用Cimatron软件的POCKET加工方法生成全螺旋加工刀路,实现定位孔加工的新方法,结果表明该方法既可以保证加工精度,又可以提高加工效率,而且具有配备刀具少、加工质量稳定等优点,值得推广使用。     

钣金件冲孔路径优化研究

数控冲裁加工中,存在冲孔路径的编排问题。本文通过比较直线／阵列法、最近邻居点法、亲近点法,提出了改进的路径优化法。经实践,该方法取得了较好的优化效果。     

Optimum process parameters to produce green ceramic complex parts

The fragility of green ceramic compacts introduces considerable difficulties during green or bisque machining. This paper demonstrates methods developed to manufacture thin wall-thin floor, complex green ceramic parts to close tolerance. Hybrid finite element (FE)/mechanistic models were utilized in the development of the green machining process. An FE model was used to define cutting edge geometry and machining parameters that would reliably produce crack free parts. Mechanistic model was used to direct cutter path generation of a 5-axis milling machine having a large axial depth of cut, and to prevent edge chipping. The optimized cutter path eliminated any need for hand work before densifying the machined part.     

Integrated tool path and feed rate optimization for the finishing machining of 3D plane surfaces

An integrated approach for the concurrent optimization of tool path and feed rate for the finishing machining of 3D plane surfaces using ball-end milling is presented in this paper. This work is important, as the developed optimization approach is readily applicable to the finishing machining of sculptured surfaces. The concurrently optimized tool path and feed rate correspond to the maximum machining efficiency and satisfy the scallop height and machining error requirements. The cutter feed direction is employed as the optimization variable. For each cutter feed direction, tool path is determined according to the scallop height requirement and feed rate is maximized with the tolerance requirement by using a mechanistic cutting force model for three-dimensional ball-end milling. Optimization results have indicated that the shortest total tool path length, favored by most existing optimization approaches, does not result in maximum efficiency because the corresponding feed rate is often constrained by the specified tolerance. The optimum cutter feed direction is in general not unique but falls within an optimum range in the finishing machining of 3D plane surfaces.     

Experimental studies on drilling tool load and machining quality of C/SiC composites in rotary ultrasonic machining

Carbon fiber reinforced silicon carbide matrix (C/SiC) composites have great potential in space applications because of their excellent properties such as low density, superior wear resistance and high temperature resistance. However, the use of C/SiC has been hindered seriously because of its poor machining characteristics. With an objective to improve the machining process of C/SiC composites, rotary ultrasonic machining (RUM) and conventional drilling (CD) tests with a diamond core drill were conducted. The effects of ultrasonic vibration on mechanical load and machining quality were studied by comparing the drilling force, torque, quality of holes exit and surface roughness of drilled holes between the two processes. The results showed that the drilling force and torque for RUM were reduced by 23% and 47.6%, respectively of those for CD. In addition, the reduction in drilling force and torque decreased gradually with increasing spindle speed, while they changed slightly with increasing feed rate. Under identical conditions, RUM gave better holes exit than CD. Moreover, because of the lower lamellar brittle fracture and pit originating from carbon fibers fracture, the roughness of surface of drilled holes obtained with RUM was lower than CD and the maximum reduction was 23%.     

Optimization of process parameters of mechanical type advanced machining processes using genetic algorithms

Generally, unconventional or advanced machining processes (AMPs) are used only when no other traditional machining process can meet the necessary requirements efficiently and economically because use of most of AMPs incurs relatively higher initial investment, maintenance, operating, and tooling costs. Therefore, optimum choice of the process parameters is essential for the economic, efficient, and effective utilization of these processes. Process parameters of AMPs are generally selected either based on the experience, and expertise of the operator or from the propriety machining handbooks. In most of the cases, selected parameters are conservative and far from the optimum. This hinders optimum utilization of the process capabilities. Selecting optimum values of process parameters without optimization requires elaborate experimentation which is costly, time consuming, and tedious. Process parameters optimization of AMPs is essential for exploiting their potentials and capabilities to the fullest extent economically. This paper describes optimization of process parameters of four mechanical type AMPs namely ultrasonic machining (USM), abrasive jet machining (AJM), water jet machining (WJM), and abrasive-water jet machining (AWJM) processes using genetic algorithms giving the details of formulation of optimization models, solution methodology used, and optimization results.     

基于误差分析的复杂曲面可侧铣判定方法研究

基于复杂曲面侧铣加工误差计算,提出了一种曲面能否通过侧铣实现高精度加工的判定方法,该方法适用于任意直纹和非直纹曲面。侧铣加工误差为待加工理论曲面与刀具运动包络曲面之间的距离,在此基础上,应用整体最优刀具路径下的最大几何偏差进行曲面可侧铣判定依据。数值仿真算例表明:该方法不仅能够有效地判定曲面能否侧铣,同时能够输出满足误差要求的最优刀具路径,加工实验也表明该方法能够极大地提高加工效率。