1、Int J Adv Manuf Technol(2002)20:357362Ownership and Copyright 2002 Springer-Verlag London LimitedDevelopment of a Practical Blank Layout Optimisation Systemfor Stamping Die DesignZ.Zhao and Y.PengDepartment of Plasticity Technology,Shanghai Jiao Tong University,Shanghai,PR ChinaBlank layout is one o
2、f the most important processes in stampingdie design.As the major cost in sheet metal stamping is thematerial cost,any efforts to minimise the scrap may result insubstantial savings not only in strip material,but also inoverall production.This paper is mainly targeted at estab-lishing a practical bl
3、ank layout optimisation system for stamp-ing die by using AutoCADs ObjectARX toolkit.The basicprinciples of blank layout optimisation are first described,andthen the general structure of the system is proposed.Notonly a suitable algorithm for layout calculation,but alsothe manufacturing requirements
4、 and user operation are fullyconsidered in this system.Finally,an algorithm for blankshape offsetting is proposed to solve the problem of self-intersection in offset curves,and the traditional 1-step trans-lation algorithm for the calculation of layout parameters isimproved to eliminate the conflict
5、 between precision andefficiency in the layout optimisation.Keywords:Blank layout;Optimization;Stamping die1.IntroductionThe stamping process is one of the earliest technical develop-ments in the manufacturing industry.The process has beenimproved continuously,and stamping products can be foundevery
6、where.Blank layout is one of the most important pro-cesses in stamping die design,and it can be defined as fittingtogether of stamping blanks to occupy the maximum amountof surface area on a coiled strip or a metal sheet.The purposeof blank layout is to increase the material utilisation andminimise
7、the amount of scrap to meet the requirements of thestamping technology.As the major cost in sheet metal stampingis the material cost,any efforts to minimise the scrap whichis in accordance with the stamping technology may result insubstantial savings not only in strip material,but in the overallCorr
8、espondence and offprint requests to:Mr Zhen Zhao,Departmentof Plasticity Technology,Shanghai Jiao Tong University,1954 HuaShan Road,Shanghai 200030,PR China.E-mail:z zhaoc?production cost as well.In addition,the result of blank layoutis the basis of strip layout design and die structure designsuch a
9、s the design of the die plate and stripper.In the past,blank layout was a manual operation which washighly dependent on the skill and experience of the designer.However,it took a long time to accumulate experience,andto answer the many problems in the practical design process,the answers to which ca
10、nnot be obtained from books ormanuals.The development of computer-aided design softwareis necessary for practical designers to improve the designquality and shorten the required design time.Based on thisrequirement,this paper is mainly targeted at establishing apractical blank layout optimisation sy
11、stem by using AutoCADsObjectARX toolkit.Algorithms for blank layout,which describe the mathematicalmodelling of the blank layout,has been proposed by manyworkers to achieve potential savings through maximum materialutilisation.Chow 1 proposed three approaches for nesting asingle pattern arranged in
12、a single row or double row on astrip of raw material.Adamowicz and Albano 2,Dori andBen-Bassat 3,and Qu and Sanders 4 proposed a two-stageapproach in which irregular shapes were initially convertedinto an approximated standard manageable shape,such as arectangle or a convex polygon,which was then ne
13、sted.Dagliand Tatoglu 5 proposed a heuristic approach which usedvarious priority rules of allocation depending on the patternshapes.Nee 6,7 and Nee and Foong 8 have developed anexperimental package,which involves algorithms and evalu-ation functions.The algorithm developed was designed toperform pai
14、rwise clustering based on an exhaustive search inwhich shapes were rotated in increments of 180 until allpossible sides were paired.The algorithm includes routines toexecute coordinate rotational and translational transformationwhilst detecting any overlapping of the shapes.Ismail andHon 9 proposed
15、an algorithm based on extracting the edgeinformation in the form of edge arrays,which are used torecognise the possible direction and obtain better pairing.Linand Hsu 10 introduced an optimal layout method to obtainthe dual-row optimal blank layout,and displayed the blanklayout graphics on the scree
16、n using AutoLisp.Tang andRajesham 11 proposed an algorithm in which the blankpattern was approximated by a polygon with a sufficient358Z.Zhao and Y.Pengnumber of sides.The grain flow direction was taken intoconsideration in this algorithm,especially for a pattern withbending.Singh and Sekhon 12 presented a method which isbased on a computerised diagraph and matrix approach.Cheokand Foong 13 developed the IAPDie system which rotates apart through a range of selected angles,and at each angle anide
