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Automated cutting tool selection and cutting tool sequenceoptimisation for rotational partsAli Orala，* M. Cemal CakirMechanical Engineering Department, Uludag University, Bursa, TurkeyAbstract：The aim of this work is to define computer-aided optimum operation and tool sequences that are to be used in Generative Process Planning System developed for rotational parts. The software developed for this purpose has a modular structure. Cutting tools are selected automatically using the machinability data, workpiece feature information, machine tool data, workholding method and the set-up number. An optimum tool sequence is characterised by a minimum number of tool changes and minimum tool travel time. Tool and operation sequence for minimum tool change are optimised with a developed optimisation method that is based on “Rank“Order Clustering2003 Elsevier Ltd. All rights reserved.Keywords: Computer-aided process planning; Tool selection; Operation sequence; Tool sequence; Optimisation.1. IntroductionThe first step and one of the main objectives of a computer integrated manufacturing system is to integratethe computer-aided design (CAD) and computeraidedmanufacturing (CAM) components. The total integration of these two components into a commonenvironment CAD/CAM is still under development.Many of the major developments have been uncoordinatedand there is a great deal of overlap in terms of their intended functions. For example, the present CAD/CAM systems have their strength in geometricaldefinition, i.e., CAD component and CAM is mostly limited to CNC programming. Other important intermediateelements such as process planning are not included. This is due to the fact that the numericalinformation generated by a CAD system is not sufficientfor process planning. Computer-aided process planningsystems available in the market are incomplete andlimited when compared to the number of CAD andCAM systems available 1.Process planning is an activity, which determinesappropriate procedures to transform a raw material intofinal product. In manufacturing industry, the taskof process planning mainly consists of determiningthe usage of available resources, such as machinetools, workholding devices, cutting tools, generation ofoperation sequence, determining machining parameters(i.e., cutting speed, feed rate, depth of cut) and selectionof auxiliary functions 2.The production cost of a component depends uponcost of the workpiece material, tooling cost and overheadcosts. Generally, these costs associated withmachining a part are fixed; thus the only scope toreduce the overall cost of the part is to focus on thetooling cost. Selection of optimal tooling directly affectsthe part cost 1. In the view of the significant reductionsin cost that can be obtained by selecting the correctcutting tool and its associated optimum cutting conditions,it is considered that any selection system that doesnot take into account all of the relevant technologicalparameters has several limitations 3. Production time isdefined as the machining time plus non-machining timeto machine a component. Determination of optimalsequence cutting tools on turret magazine of a CNCmachine tool is an important task for achievement ofoptimal machining sequences for reducing total nonmachiningtime 4.The aim of this work is to define computer-aidedoptimum operation and tool sequencing to be used inthe generative process planning system developed forrotational parts (GPPS-RotP).2. State-of-art of cutting tool selectionThe objectives of tool selection exercise are to selectthe best tool holder(s) and insert(s) from availablecutting tools database. In the past, the operator wouldselect the best tool set according to his experience, whichcannot be converted into logic or algorithmic rules. Thismethod is called as manual approach, which commonlyresults in errors and inconsistencies. Disadvantages ofmanual approaches led to development of automatedapproaches that aimed to reduce the probability oferrors and inconsistencies. The correct choice of cuttingtools is determined by the overall part configuration,rather than by individual contour section or workpieces.Computer-aided tool selection systems have been developedfor this purpose. Plummer and Hannam 5 tookworkpiece material and profile geometry into accountbut ignored selection of carbide grade, chipbreaker,cutting edge length, and nose radius. Giusti et al. 6developed the expert tool selection module for turningoperations. This module depends heavily upon theexpertise of the operator for an efficient structuring ofthe rule-based approach. Chen et al.7 developed anautomatic tool selection system for rough turning on aCNC lathe. Selection is made from appropriate toollibrary employing a heuristic method in order to reducethe search time. Tool selection procedure searches forthe best tool for a desired operation. Out of the variouspotential tools, the only criterion for tool selection isleast cost. Chen and Hinduja 8 used a tool selectionprocess by checking collision between tool and workpieceor machine tool for workpiece to be machined. In case of any collision, use of two or more tools formachining is considered.Hinduja and Huang 2 carried out a study called OPPLANin which they assumed that single tool was usedfor recess or groove machining. Domazet 9 used ahybrid approach in that both algorithms and productionrules matrix method were used for tool selection; cuttingconditions were determined using tool manufacturerdata. Fernandes and Raja 1 carried out tool selectionprocess for external and internal turning, but theyconsidered only cylindrical and face turning operations.Edalew et al. 10 developed a computer-based intelligentsystem for automatic tool selection system. Thissystem was operated in a fully interactive mode andinformation associated with a particular subject, such aspart status, feature ordering (up to 12 feature typescould be used to describe the component) and thecomponent materials were incorporated into system.The analysis of the component included feature specificationand dimensions, which were entered by the user.3. Tool selection parametersSuccess in metal cutting depends on the selectionproper cutting tool both in respect to the tool andmaterial to be machined. The elements that influence thetool selection decision are: (i) workpiece materials, i.e.,chemical and metallurgical state, etc., (ii) part characteristic,i.e., geometry, accuracy, finish and surfaceintegrity, etc. (iii) machine tools characteristics includingthe workholder, tool number of the tool magazine andtool holder dimension, (iv) cutting tools or insertcharacteristics 11.Cutting tools selection is a very important subtaskinvolved in process planning systems. Tool selectionmodule uses knowledge such as geometry for workpiece(feature recognition), surface finish, shape, location anddirection tolerance, material of the workpiece, machinabilitydata such as speed, feed rate, depth of cut,machine tool, set-up number, process type, workholdingdevice. GPPS-RotP has seven modules as shown inFig. 1.3.1. Feature recognitionThe first step in automatic process planning activitiesis recognising the geometry of workpiece. Featurerecognition is a design interface for process planningwhich is an automatic transfer of part description datafrom CAD system to process planning system 12. Thepart-feature recognition system that is developed has gotsimilarities with syntactic pattern-recognition techniquedeveloped by Fu 13. Fu used 24 pattern primitives toformalise the pattern-recognition process. In the presentwork, 16 pattern primitives were defined as shown inFig. 2. They are basically different shapes of line and arcsegments with a start point, end point and a direction.Turning surfaces can be defined an elements such asdiameter, taper, face, arc, chamfer, recess or groovingwith the aim of pattern primitive. For example,a diameter can be represented by either the patternprimitive “A” or “C”, a face can be represented by ”D”or “B”.In recognition, features are classified into two groups:primary features and secondary features as shown inFig. 3. Primary form features are cylinder, taper andarcs. Secondary form features are form features otherthan cylinders, tapers and arcs often found on rotationalcomponents. Giving only the upper half of the 2Dprofile information, which is a series of lines and arcsegments, does the definition of the geometry of arotational part.4. Cutting tool selectionCutting tools that are considered consist oftwo main components: the tool holder and indexableinsert. The objective of any tool selection is todetermine several parameters such as tool holder(clamping system, type, point angle, hand of cut, size,etc.), insert (shape, size, grade, nose radius, etc.),cutting conditions (in this work insert size isdetermined according to specified cutting data), typeof coolant (if required) and total cost of machining thecomponents 17.The outline for selecting indexable turning toolselection is first to select the tool holder system, followedby the tool holder and finally the suiting insert. In thepresent work, tool selection is feature based and fullyautomatic. Required information for tool selection are:machinability data, feature recognition for workpiece,machine tool to be used, workholding device and initialoperation sequence.Initial operation sequence consists of four basic steps:machining of right-external zone (if workpiece consistsof two zones, right zone has machining precedence),machining of right-internal zone, machining of leftexternalzone, machining of left-internal zone. Initialoperation sequence is changed automatically accordingto the clamping surface defined by clamping methodmodule.The selection of tool holders is based on the basicmachining operations required to transform theworkpiece into desired shape. The first check is thatthe tool holder is of a suitable overall type. Certaincritical dimensions of the cutter must also bechecked against the shape of the operation, such aseffective cutting edge length and gauge length. Theoverall size of the tool must also fit into the machinetool magazine 18.4.1. Cutting tool selection for rough turning operationsThe various geometrical parameters definingindexable inserts for turning tools are included in ISOcode. Tool selection module not only takes theparameters in the ISO codes into consideration, butcarbide grades and functions of tools as well. In thepresent work, inserts with 95_ of approach angleand 80_ of point angle are considered firstfor rough turning operations. This enables them tomachine stepped profiles without any geometriccollision problem.4.2. Tool selection for recess and groove turningIn comparison to tool selection criteria used for roughturning, more comprehensive tool selection criteriashould be used for recessing and grooving.The recess term used in this paper refers to a featurethat has a minimum width of 16mm and that can bemachined by one or two tools of opposite hands 2. Thestudy reported herein adopts this definition. Yet it doesnot use this definition as a sole criterion for cutting toolselection for groove and recess. The width of a feature iscommonly used as a criterion for classifying it as a groove.If no accessibility problem occurs during machining, thenanother cutting tool other than grooving tool can beselected. The characteristics of the features such as width,depth, and concave, convex and taper parts should also beconsidered in selecting appropriate cutting tools.In tool selection process, it is necessary to analyse thefeature information through a series of IFyTHENstructures. Thus, appropriate tool holder and insert areautomatically chosen from the tool library. Insert withthe largest point angle is the most preferred one in termsof insert strength, therefore is the starting point. However,large point angle may cause a problem in accessing to thefeature. Accessibility to the feature is then checked for thetool with a smaller point angle. This control routine iscarried on until the most appropriate tool is found. If thiscontrol routine cannot find any appropriate tool forrecessing, the accessibility of two tools to the feature istested via methods of geometric analyses.Different criteria to be used to machine a recess with asingle tool and appropriate tool parameters are given inTable 3. Different recessing methods and tools aresketched in Fig. 11. Recesses that can be machined witha single tool or two tools are shown in Fig. 11a and c,respectively. For any problem in accessing to the featurewith all available tools, accessibility of the feature usingtwo tools is checked through methods of geometricanalyses. Geometric analyses are applied to check anycollision between workpiece and tool that preventsaccessibility to the feature. If there is any collision, thegeometry of workpiece is temporarily modified as shownin Fig. 11b. For the un-machined region on the recess/groove, another tool with an opposite feed direction ischosen (Fig. 11c). For the temporarily modified geometry,there should be no collision between workpiece and tool tobe able to machine the recess/groove. If no collision isdetected, two tools are assigned for the operation.Geometric analysis in tool selection module ATOS (AutomaticTool Selection Module) is carried out as follows:1. During the last pass of the first tool that does themachining, first contact point K of tool on the groovebase is determined.2. Groove contact point L of the second tool thatfinishes the machining is determined。6. ConclusionIn this work, cutting tool selection was carried out bytaking the geometry of workpiece, surface roughness,chip breaking area of the cutting tools, machinabilitydata, machine tools information, workholding methodsand number of set-ups into consideration. Tools arechosen and operation sequence is then optimised with adeveloped optimisation method that is based on “RankOrder Clustering“.More than 500 practical rules and years of experienceare used in the determination of machinability data,machine tool, workholding method and cutting tools;and the application of the software into practical lifeshows that the system developed is capable of providingfast and successful process plans for complex workpieces.。References1 Fernandes J, Raja HV. Incorporated tool selection systemusing object technology. Int J Machine Tools Manuf2000;40:154755.2 Hinduja S, Huang H. OP-PLAN: an automated operationplanning system for turned components. Proc Inst Mech Eng B1989;203:14558.3 Riberio MV, Coppini NL. An applied database system for theoptimisation of cutting conditions and tool selection. J MaterProcess Technol 1999;9293:3714.4 Dereli T, Filiz IH. Allocating optimal index positions on toolmagazines using genetic algorithms. Robotics Autonom Syst2000;33:15567.5 Plummer JCS, Hannam RG. Design for manufacturing using aCAD/CAM system: a methodology for turned parts. Proc InstMech Eng 1983;197:18495.6 Giusti F, Santochi M. COATS: an expert module for optimal toolselection. Ann CIRP 1986;35(1):33740.7 Chen SJ, Hinduja S, Barrow G. Automatic tool selection forrough turning operations. Int J Mach Tools Manuf1989;29(4):53553.8 Chen SC, Hinduja S. Checking for tool collisions in turning.Comput Aided Des 1988;20(5):2819.9 Domazet D. The automatic tool selection with the productionrules matrix method. Ann CIRP 1990;39(1):497500.10 Edalew KO, Abdalla HS, Nash RJ. A computer-based intelligentsystem for automatic tool selection. Mater Des 2001;22:33751.11 Mookherjee R, Bhattacharyya B. Development of an expertsystem for turning and rotating tool selection in a dynamicenvironment. J Mater Process Technol 2001;113:30611.12 Kim IH, Cho KK. An integration of feature recognition andprocess planning functions for turning operation. Comput IndEng 1994;27(14):10710.13 Li RK. A part-feature recognition system for rotational parts. IntJ Prod Res 1988;26(9):145175.14 Machining data handbook, Cincinnati machinability, 3rd ed.USA: Data Centre; 1980.15 Tool and manufacturing engineers handbook, vol. 1. Machining.Dearborn, MI: Society of Manufacturing Engineers; 1983.16 Hinduja S, Huang H. Automatic determination of work-holdingparameters for turned components. Proc J Eng Manuf B1989;203:10112.17 Arezoo B, Ridgway K, Al Mahari AMA. Selection of cuttingtools of machining operations using an expert system. ComputInd 2000;42:4358.18 Carpenter ID, Maropoulos PG. A flexible tool selection decisionsupport system for milling operations. J Mater Process Technol2000;107:14352.19 Tool Catalog, turning tools. Sandvik Coromant, 2000.20 Singh N. Systems approach to computer-integrated design andmanufacturing. New York: Wiley; 1995.自动化的切割工具选择和切割工具序列优化为旋转的零件阿里, *, M. Cemal Cakir机械工程部门, Uludag 大学, 伯萨, 土耳其摘要：这工作的目标将定义将被使用在生产过程的计算机辅助的最宜的操作和工具序列规划系统显现了出为旋转的零件。软件被开发为这个目的有一个模件结构。切割工具是自动地选择使用可切削性数据, 制件特点信息, 机械工具数据的方法和设定数字。一个最适宜的工具序列为工具变动和极小的工具旅行时间的一个最小数字描绘。工具和操作序列为极小的工具变动被优选以根据等级的一个被开发的优化方法命令成群“。 2003 年Elsevier 有限公司。版权所有。主题词: 计算机辅助的过程计划; 工具选择; 操作序列; 工具序列; 优化。1. 介绍第一步和a 的当中一个主要宗旨计算机集成制造系统将集成计算机辅助设计(CAD) 并且计算机辅助制造的(CAM) 组分。共计这两个组分的综合化入共同性环境CAD/CAM 仍然是在发展中。许多主要发展不协调并且有很多交叠根据他们的意欲的作用。例如, 礼物 CAD/CAM 系统有他们的力量在几何定义, 即, CAD 组分和CAM 主要是对CNC 编程限制。其它重要中间体元素譬如处理计划不是包括。这归结于数字的事实信息由计算机辅助设计系统引起不是充足的为处理计划。计算机辅助的过程计划系统可利用在市场上是残缺不全的和有限当与CAD 的数字比较和 CAM 系统可利用 1 。处理计划是活动, 确定合适规程变换原材料成最终产品。在制造工业, 任务处理计划主要包括确定可利用的资源用法, 譬如机器工具, 工件夹紧的设备, 切割工具, 世代操作序列, 确定用机器制造的参量 (即, 切开的速度, 供给率, 裁减的深度) 并且选择辅助函数 2 。组分的生产成本依靠制件材料的费用, 用工具加工的费用和天花板费用。通常, 这些费用与交往用机器制造零件是固定的; 因而唯一的范围减少零件的整体费用是集中于凿出的装饰费用。优选的凿出的装饰直接影响的选择零件费用 1 。根据重大减少在可能由选择获得正确的费用切割工具和它伴生的最宜的切口情况, 它被考虑的任一个选择系统不考虑到所有相关技术参量有几限制 3 。生产时间是定义如同机时加上非用机器制造的时间用机器制造组分。决心优选程序化切割工具在CNC 的塔楼杂志机械工具是一项重要任务为成就优选的用机器制造的序列为减少总nonmachining 时间 4 。这工作的目标将定义计算机辅助最宜的操作和工具程序化被使用生产处理规划系统显现了出为旋转的零件(GPPS-RotP) 。2. 切割工具选择状态艺术工具选择锻炼宗旨将选择最佳的工具holder(s) 和insert(s) 从可利用切割工具数据库。从前, 操作员会选择最佳的工具箱根据他的经验, 不能被转换成逻辑或算法规则。这方法叫作为手工方法, 共同地结果在错误和不一致。不利指南方法导致发展自动化接近那打算减少可能性错误和不一致。切口正确选择工具由整体部份配置确定, 而不是由各自的等高部分或制件。计算机辅助的工具选择系统被开发了为这个目的。Plummer 和Hannam 5 采取了制件材料和外形几何但碳化物等级, chipbreaker 的被忽略的选择, 先锋长度, 和鼻子半径。Giusti 等 6 发展了专家的工具选择模块为转动操作。这个模块沉重取决于操作员的专门技术为一高效率构造基于规则的方法。陈等。 7 开发了自动工具选择系统为概略转动在a CNC 车床。选择由适当的工具被做图书馆使用一个启发式方法为了减少查寻时间。工具选择做法查寻为为渴望的操作的最佳的工具。在各种各样外面潜在的工具, 唯一的标准为工具选择是最少费用。陈和Hinduja 8 使用了一种工具选择过程由检查碰撞在工具和制件之间或为制件的机械工具用机器制造。在任何碰撞案件, 对二个或更多工具的用途为用机器制造被考虑。Hinduja 和黄 2 执行了研究称OPPLAN 在哪些他们假设, 唯一工具被使用了为凹进处或凹线用机器制造。Domazet 9 使用了a 杂种方法算法和生产规则矩阵方法被使用了为工具选择; 切口情况是坚定的使用工具制造商数据。Fernandes 和Raja 1 执行了工具选择过程为外在和内部转动, 但他们认为只圆柱形和面孔转动的操作。 Edalew 等 10 开发了一计算机为主聪明系统为自动工具选择系统。这系统被管理在一种充分地对话方式下和信息联系了一个特殊主题, 譬如部份状态, 特点定货(12 以型为特色能被使用描述组分) 和组分材料被合并了系统。对组分包括的特点规格的分析并且维度, 由用户输入。3. 工具选择参量成功在金属切口取决于选择适当的切割工具关于工具和材料用机器制造。影响的元素工具选择决定是: (i) 制件材料, 即, 化工和冶金状态, 等, (ii) 部份特征, 即, 几何、准确性、结束和表面正直, 等(iii) 机械工具特征包括 workholder, 工具杂志的工具数字和工具囤户维度, (iv) 切割工具或插入物特征 11 。切割工具选择是一个非常重要子任务介入在处理规划系统。工具选择模块使用知识譬如几何为制件 (特点认识), 表面结束, 形状, 地点和方向容忍, 制件的材料, 可切削性数据譬如速度, 供给率, 裁减的深度, 机械工具, 被设定的数字, 处理类型, workholding 设备。GPPS-RotP 有七个模块依照被显示图1.3.1. 特点认识第一步在自动处理计划活动认可制件几何。特点认识是一个设计接口为处理计划哪些是部份描述数据自动调动从计算机辅助设计系统到处理规划系统 12 。部份特点被开发的识别系统相似性以语法pattern-recognition 技术由Fu 13 显现出。Fu 使用了24 样式原始形式化pattern-recognition 过程。在礼物依照被显示工作,
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