孔加工刀具交换问题及后续优化

在孔群加工中,总加工成本由刀具成本、加工成本、非加工刀具行进时间、刀具换刀成本组成。在加工有多个孔模型的零件时,为了有效地得到刀具交换问题的优化解,采用基于启发式算法的求解方法。在得到优化解后,提出了基于孔模型工序矩阵的进一步优化方法。     

具有工件约束的模具制造优化调度算法研究

为解决具有工件约束的模具制造优化调度问题,提出了一种利用蚁群算法和优先分配启发式调度算法相结合的调度算法。该算法能够方便地描述问题的约束条件的特点。首先,由蚁群算法确定模具零件各工序所用的加工机床,用节点模式下的有向图描述问题的解空间,用蚂蚁种子信息素踪迹更新策略对信息素进行更新,以获得问题的解;然后,利用优先分配启发式调度算法确定在同一台机床上加工的各零件的先后顺序。实验结果验证了算法的有效性。     

基于多目标决策的车间作业调度算法研究

为解决具有多目标约束的Job-shop问题,提出了一种利用模糊综合评判规则和优先分配启发式算法相结合的调度算法.首先,用层次分析法给出各评判目标的评价权重;再由模糊综合评判规则确定目标权重下零件各工序所用的加工机床;最后,利用优先分配启发式调度算法确定在同一台机床上加工的各零件的先后顺序.实验结果证明了算法的有效性.     

基于多目标决策的车间作业调度算法研究

为解决具有多目标约束的Job-shop问题，提出了一种利用模糊综合评判规则和优先分配启发式算法相结合的调度算法。首先，用层次分析法给出各评判目标的评价权重；再由模糊综合评判规则确定目标权重下零件各工序所用的加工机床；最后，利用优先分配启发式调度算法确定在同一台机床上加工的各零件的先后顺序。实验结果证明了算法的有效性。     

CNC机床中刀具交换问题的启发式算法

刀具交换问题是指在一台CNC机床上加工N个作业时，在优化作业加工次序和刀具装载策略的过程中，使CNC机床的换刀次数最少。为了有效地搜索到刀具交换问题的优化解，本文提出了基于定向搜索的启发式算法的求解方法。通过实验数据的验证，本文提出的算法具有简单、计算速度快以及效率高的特点。     

面向铣削特征的刀具轨迹生成

介绍了一种面向铣削特征的刀具轨迹生成方法。用户在特征库的支持下首先对所要加工的零件进行特征描述,形成零件的描述文件,然后系统根据描述的特征信息自动生成面向加工中心的加工工艺和数控源代码,生成铣削加工的刀具轨迹,最后利用功能强大的仿真模块对生成的数控代码进行仿真检验,实时显示刀具中心位置,切削用量等参数,若发现数控代码有误,可及时方便地进行修改。     

FMS刀具准备系统研究

围绕刀具准备系统的研究与开发 ,论述了刀具准备系统的总体结构和刀具寿命管理、刀具贮备管理、GT概念下刀具分配策略三个功能模块 ,利用相对磨损率来衡量刀具的磨损程度 ,从而对刀具寿命进行优化 ;根据从 MRP和 MPS得到的信息以及刀具的使用数据 ,生成基于成本优化的刀具补充策略 ;并将成组技术、遗传算法及虚拟刀具库思想 ,应用于刀具分配 ,解决FMS中刀具的优化分配问题。     

一种新的数控刀具干涉校验快速算法

数控加工中，刀具与零件之间的干涉校验问题可以转化为刀具切削切的轨迹与零件轮廓之间的求交问题。本文提出了新的判断交点的数学方法。利用此方法，并采用区域重叠测试原理，讨论了新的快速刀具干涉校验算法。     

一种新型的作业车间调度算法的研究与实现

将工件的剩余加工时间分为相对剩余加工时间和绝对剩余加工时间 ,提出了优先分配启发式算法的一种新的优先分配规则 ,即相对剩余加工时间最大的概念 ,把调度分成多个阶段的部分调度 ,通过比较部分调度集合中的可调度工序的相对剩余加工时间 ,求解出每个部分调度的最优解 ,从而使整个调度达到全局最优或近似最优。最后 ,开发出调度软件 ,验证了算法在工程中的可行性、有效性。     

球头铣刀刀具磨损建模与误差补偿

针对刀具磨损度量方式和模型建立的问题,以球头刀具为研究对象,提出球头铣刀刀具磨损的度量方式,建立球头刀具磨损模型.以复映磨损在硬度较软加工材料上的方式测量球头刀具磨损,确定刀具磨损模型系数,给出刀具磨损模型系数确定的具体实现方法.加工试验验证球头刀具磨损度量方式的合理性和所建立刀具磨损模型的正确性,同时针对数控铣削加工中球头铣刀刀具磨损引起的误差提出离线仿真误差补偿算法,给出离线仿真误差补偿算法的具体实现步骤,通过建立的刀具磨损引起的加工误差模型仿真获得加工走刀步的误差.对于误差超差的走刀步,预先修改数控加工(Numerical control,NC)程序,保证实际加工零件满足精度要求.误差补偿验证试验表明所提出的离线仿真误差补偿算法的正确性和有效性.     

MACHINING PARAMETERS OPTIMIZATION FOR ALUMINA BASED CERAMIC CUTTING TOOLS USING GENETIC ALGORITHM

Alumina-based ceramic cutting tools can be operated at higher cutting speeds than carbide and cermet tools. This results in increased metal removal rates and productivity. While the initial cost of alumina based ceramic inserts is generally higher than carbide or cermet inserts, the cost per part machined is often lower. Production cost is the main concern of the industry and it has to be optimised to fully utilize the advantages of ceramic cutting tools. In this study, optimization of machining parameters on machining S.G. iron (ASTM A536 60-40-18) using alumina based ceramic cutting tools is presented. Before doing the optimization work, experimental machining study is carried out using Ti [C,N] mixed alumina ceramic cutting tool (CC 650) and Zirconia toughened alumina ceramic cutting tool (Widialox G) to get actual input values to the optimization problem, so that the optimized results will be realistic. The optimum machining parameters are found out using Genetic algorithm and it is found that Widialox G tool is able to machine at lower unit production cost than CC 650 tool. The various costs affecting the unit production cost are also discussed.     

MACHINING PARAMETERS OPTIMIZATION FOR ALUMINA BASED CERAMIC CUTTING TOOLS USING GENETIC ALGORITHM

Alumina-based ceramic cutting tools can be operated at higher cutting speeds than carbide and cermet tools. This results in increased metal removal rates and productivity. While the initial cost of alumina based ceramic inserts is generally higher than carbide or cermet inserts, the cost per part machined is often lower. Production cost is the main concern of the industry and it has to be optimised to fully utilize the advantages of ceramic cutting tools. In this study, optimization of machining parameters on machining S.G. iron (ASTM A536 60-40-18) using alumina based ceramic cutting tools is presented. Before doing the optimization work, experimental machining study is carried out using Ti [C,N] mixed alumina ceramic cutting tool (CC 650) and Zirconia toughened alumina ceramic cutting tool (Widialox G) to get actual input values to the optimization problem, so that the optimized results will be realistic. The optimum machining parameters are found out using Genetic algorithm and it is found that Widialox G tool is able to machine at lower unit production cost than CC 650 tool. The various costs affecting the unit production cost are also discussed.     

A technologically oriented approach for the economic tool selection and tool balancing of milled components

A technologically oriented tool selection and tool balancing system for milled components is presented. The system is capable of selecting the most economical tool set and, where necessary, adjusting the cutting conditions for all the features of a batch of components. Several key parts of the system such as the method for estimating the remaining tool life of a cutter used for selected different cuts, the cost equation used and the method of searching for the most economical tool set are discussed. The system has been used to analyse the tools required for the machining of a typical milled component. This analysis considered the influence of batch size, the number of repeat batches, the number of sister tools, inventory cost and of varying the cutting velocity within a given feature.     

基于PC控制的数控车削精加工对刀谬误修正

数控加工前，必须进行对刀。精加工的对刀要求十分严格，各项影响刀具与工件相对位置关系的因素都要考虑清楚。文章着重分析了对刀中普遍存在的两种不恰当做法，对数控精加工有着重要的意义。     

Job scheduling and management of wearing tools with stochastic tool lifetimes

The problem of scheduling jobs using wearing tools is studied. Tool wearing is assumed to be stochastic and the jobs are processed in one machining centre provided with a limited capacity tool magazine. The aim is to minimize the expected average completion time of the jobs by choosing their processing order and tool management decisions wisely. All jobs are available at the beginning of the planning period. This kind of situation is met in production planning of CNC-machines. Previous studies concerning this problem have either assumed deterministic wearing for the tools or omitted the wearing completely. In our formulation of the problem, tool wearing is stochastic and the problem becomes very hard to solve analytically. A heuristic based on genetic algorithms is therefore given for the joint problem of job scheduling and tool management. The algorithm searches the most beneficial job sequence when the tool management decisions are made by a removal rule taking into account the future planned usage of the tools. The cost of each job sequence is evaluated by simulating the job processing. Empirical tests with heuristics indicate that by taking the stochastic information into account, one can reduce the average job processing time considerably.     

一种支持型腔粗加工刀具序列高效优化的刀具筛选方法

型腔加工是现代数控加工中广泛面临的一类加工问题。刀具筛选是型腔粗加工刀具序列优化过程中的一个重要环节。现有的基于几何、设备和工艺等约束的刀具筛选方法并不能判别因刀具之间相互制约而产生的冗余刀具,降低了刀具序列优化的效率。通过对比刀具组合过程中因不同刀具的优势互补而产生的效益增量与因换刀带来的相关效益损失量,建立一种用于判断刀具序列是否有效的分析模型;在此基础上,从刀具序列的组合形态的角度构造并证明一种可以判别部分冗余刀具的规则,并将其与基于几何、设备和工艺等约束的刀具筛选方法相串联,得到一种可支持刀具序列高效优化的刀具筛选方法;研究新方法的实现技术,包括刀具加工能力的估算方法和刀具组合有效性的计算方法;算例结果表明所提方法在去除冗余刀具上的效果明显,能为刀具序列的高效优化提供有效支持。     

刀具涂层材料的发展

采用涂层技术可有效提高切削刀具的使用寿命,使刀具获得优良的综合机械性能,从而大幅度提高机械加工效率.我国的刀具涂层材料经过多年发展,目前正处于关键时期,充分了解国内外刀具涂层材料的现状及发展趋势,有计划、按步骤地发展刀具涂层材料,对提高我国切削刀具制造水平具有重要意义.     

加工中心刀具智能拼装

加工中心刀具管理是目前国内外生产管理中的一个技术关键,本文介绍了郑州纺织机械厂的加工中心刀具管理系统,着重阐述了基保的智能拼装技术。     

21世纪初我国切削加工与刀具技术展望

切削加工与刀具在21世纪初仍将是制造技术的基础工艺和主要工艺装备,并将在开发新的加工工艺、革新传统工艺上发挥新的作用。高速切削、硬切削、干切削工艺将进入实用阶段。硬质合金刀具、超硬刀具、涂层刀具将成为切削刀具的主体,在今后10～15年内整体切削效率可提高1～2倍。刀具技术发展的主流是:进一步提高精度、效率和可靠性,安全和环保亦将成为重要课题,数量的增长将退居次要位置。激光切削或激光辅助切削等新的加工方法将得到开发。工具行业将更新观念,面向加工技术,为用户提高加工效率、降低成本提供成套切削技术。