All-Embracing Manufacturing: Roadmap System PDF
Preview All-Embracing Manufacturing: Roadmap System
All-Embracing Manufacturing InternationalSerieson INTELLIGENTSYSTEMS, CONTROL ANDAUTOMATION: SCIENCE AND ENGINEERING VOLUME59 Editor ProfessorS.G.Tzafestas,NationalTechnicalUniversityofAthens,Greece EditorialAdvisoryBoard ProfessorP.Antsaklis,UniversityofNotreDame,NotreDame,IN,USA ProfessorP.Borne,EcoleCentraledeLille,Lille,France ProfessorD.G.Caldwell,UniversityofSalford,Salford,UK ProfessorC.S.Chen,UniversityofAkron,Akron,Ohio,USA ProfessorT.Fukuda,NagoyaUniversity,Nagoya,Japan ProfessorS.Monaco,UniversityLaSapienza,Rome,Italy ProfessorG.Schmidt,TechnicalUniversityofMunich,Munich,Germany ProfessorS.G.Tzafestas,NationalTechnicalUniversityofAthens,Athens,Greece ProfessorF.Harashima,UniversityofTokyo,Tokyo,Japan ProfessorN.K.Sinha,McMasterUniversity,Hamilton,Ontario,Canada ProfessorD.Tabak,GeorgeMasonUniversity,Fairfax,Virginia,USA ProfessorK.Valavanis,UniversityofDenver,Denver,USA Forfurthervolumes: http://www.springer.com/series/6259 Gideon Halevi All-Embracing Manufacturing Roadmap System 123 GideonHalevi IndustriaandManagement Technion DubnovSt.20a TelAviv,Israel ISBN978-94-007-4179-9 ISBN978-94-007-4180-5(eBook) DOI10.1007/978-94-007-4180-5 SpringerDordrechtHeidelbergNewYorkLondon LibraryofCongressControlNumber:2012934823 ©SpringerScience+BusinessMediaDordrecht2012 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartof thematerialisconcerned,specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation, broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionorinformation storageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilarmethodology nowknownorhereafterdeveloped.Exemptedfromthislegalreservationarebriefexcerptsinconnection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher’slocation,initscurrentversion,andpermissionforusemustalwaysbeobtainedfromSpringer. PermissionsforusemaybeobtainedthroughRightsLinkattheCopyrightClearanceCenter.Violations areliabletoprosecutionundertherespectiveCopyrightLaw. Theuseofgeneraldescriptivenames,registerednames,trademarks,servicemarks,etc.inthispublication doesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfromtherelevant protectivelawsandregulationsandthereforefreeforgeneraluse. While the advice and information in this book are believed to be true and accurate at the date of publication,neithertheauthorsnortheeditorsnorthepublishercanacceptanylegalresponsibilityfor anyerrorsoromissionsthatmaybemade.Thepublishermakesnowarranty,expressorimplied,with respecttothematerialcontainedherein. Printedonacid-freepaper SpringerispartofSpringerScience+BusinessMedia(www.springer.com) Preface Thisbookpresentsanew(improved)productionmanagementsystem. Theuniquenessofthesystemliesinitsnotionsandtools,whicharelistedhere inrandomorderofimportance: • Routingisavariable • Thetaskofaprocessplanneristocreatearoadmapandnottocreaterouting • Productionplanningtreatseachorderindependently • Thesystemcreatesaworkingproductstructurebasedonlevelproductstructure • Setcriticalorderandgiveitpriorityinproductionplanning • Thesystemeliminatesorrectifiesbottlenecksinproductionplanning • Shopfloorcontrolismaintainedbyresourcesearchesforfreeoperations. • Itenablesalterationsinproductionplansatanypointintheprocess • Itservesasdecisionsupportsystem(DSS)tomanagement Theoretically,productionplanningandcontrolisbasicallyaverysimpletask. A manufacturing plant receives orders for a product or a number of products, alongwith informationsuchasquantitiesanddeliverydates. Theresourcesofthe plantsareknown,theproductsarelistedina“Bill-of-Materials”(BOM)areknown, and the routing is given. The task of productionplanningis to make sure that the orderswillbereadyontimeinthemosteconomicalprocess.That’sall. Yet the commonly shared concept is that production planning and control is a very complex task. Over 130 complex production-planningmethods have been devisedovertheyears.Yetthesearchfor“THE”methodisongoing. This search has covered all sorts of ideas except one, emulating modes of humanthought.Humanthinkingisveryflexible;itallowssettingofobjectivesand considerationofvariousmethodstoaccomplishthem,andwhenadisruptionoccurs itmotivatesalterationsinoriginaldecisionsinordertoresolvetheproblem. For example: If you want to go from point A to point B, you would probably studyamapandplantheoptimumroutetotake.Thisisa“presenttime”decision. However, at another time when you have to travel the same way, say at night, you might change the route; in winter you probably would look for a route with maximum shelter from precipitation. In summer you might choose a route that v vi Preface provides protection from the sun. In springtime you might choose a route with a particularly nice view. Despite the original routing decision, if you run into disruptions,suchasablockedroad(bottleneck),multipleredtrafficlightsorheavy truck traffic, you might decide that, instead of waiting for the obstacle to clear, it isbettertoonceagainconsulttheroadmapandchangetherouteinordertofinda pathwithnoobstacles.Suchachangeispossibleateachjunction.Itmightresultin alongerroutebutitwillbefasterintime.Theoriginaldecisionwouldnotprevent thinkinghumanfromadaptinganewroute. Such a method may be used in production planning and scheduling. But why wasitnotevenconsidered?Becausethereisnoroadmaptoconsultforalternative routes,i.e.,thereisnoGPStoprovideguidancemid-process.Theprocessingrouting consistsoffixeddataandinstructions.Itwasdefinedatsometimeinthepastandis validtillsomeeventcallsforalterations. Theonewhosettheroutingistheprocessplanner,whoisalwaysverybusywith generatingroutingfornewitemsandcannothandlejobsthathavealreadyarouting butwithminororderchanges,suchasquantity. Furthermore, there are several criteria of optimizations that are affected by routingsuchas: • Optimizationofasingleoperation • Optimizationofanindividualitem • Optimizationofproducingaproduct • Optimizationofproducingaproductmix • Optimizationoffactorybusiness Asingleroutinginacompany’sdatabasecannotaccommodateallthesecriteria; itrequiresaroadmapmethod. There was an attempt to develop a computer aided process planning (CAPP) program to generate routing from a drawing (CAD), but in spite of all the effort invested,thisprojectdidnotmaterializedandtheideafadedaway. Thus routing remains as a reflection of fixed data in the company’s data base andcannotaddflexibilitytoproductionplanning.Toovercomeresourceoverload, inparticularjobscompetingforaccesstoresources,theplannermustdecidewhich jobwillgetpriority.Otherjobsmustbeshiftedbackwardorforwardintheschedule, whichmightmeanincreasingworkinprocessordelayinorderdelivery. 1 ThisBookPresents aMethod ofConstructing anImportant Tool:A Roadmap 1.1 Routing:Process Planning Routing is the stage that transforms raw material into the form specified by the engineeringdrawing.Thistaskshouldbecarriedoutseparatelyforeachpart,sub- assemblyandassemblyoftheproduct. Preface vii Process planning is a decision making task for which the prime optimization criterion is to meet the specifications in the engineeringdrawings. The secondary criteriaarecostandtimewithrespecttotheconstraintssetbycompanyresources, tooling,know-how,quantityrequired,andmachineload balancing.Someof these constraintsarevariableorsemi-fixed;hence,theoptimumsolutionobtainedwillbe validonlywithrespecttothoseconditionsconsideredatthetimethedecisionswere made. Therefore,underroadmaptechnologytheprocessplannertaskisnottospecify routingbutrathertocreateadatabase(spreadsheet)containingallpossibleprocess steps.Routingcanbegeneratedautomaticallyinasplitsecond,bytheusertaking intoconsiderationthepresent(on-line)stateofproduction. Theroadmaproutingconceptdividesthetaskintothreestages: Stage 1: Technology stage; Generates BP—Basic Process. It is the “best” possibleprocessfromatechnologystandpoint.Itdoesnotviolateanyphysicallaw. Itistheoreticalfromaspecificshopviewpoint. Stage2:Transformationstage;itconstructanOperation—Resourcesmatrixthat lists all required operations, as generated by the BP. It searches the database to determine available resources and transform processing time of each operation in ordertoconsidertherestraintsoneachspecificresource,andbuildsthecontentof thematrix(Ti,j—Thetimetoprocessoperationionmachinej). Stage 3: Decision (mathematics) stage; Computes the path and sequence of operations that will result in the optimum routine according to the criteria of optimization. The matrix format represents almost an infinite number of possible processes. Thereforethetaskofprocessplannerisnottosetroutingbutrathertogenerate aroadmapofpossibleprocesses,andleteachdepartmentalterroutingaccordingto thecurrenton-linemanufacturingstate. A roadmap method of generating routing is independent of human process plannersandeachusermaygeneratearoutingsuitabletothebatchbeingprocessed, suchas: • Minimummaterialscost • Maximumproduction • Maximumprofit • Minimuminvestment • Minimumprocessingcost • Mediumquantitydemand • Highquantitydemand Thistoolmayresolveanoverload,notbydeferringjobprocessingtimebutrather byselecting,whenpossible,differentroutingoperations. Roadmap routing generation programs have a feature that can respond to user requests, such as: select criteria of optimization; block resource; forced routing; alternatives;comparecosttoprocessingtime,etc. viii Preface 1.2 ProductionPlanning The traditional approach to planning and execution regards routing as static and unalterable, therefore the planning is simple, but it robs the shop of production flexibilityandefficiency. Thebasicnotionsofhierarchicalapproachtechniquesare: • Usethe“best”routingforthejob. • Usingthe“best”routingformaximumproductionoptimizationwillresultinthe shortestthroughput. • Thelargerthebatchquantity,thehighertheproductivity. • Releasing jobsbasedonMRP(orERP)to theshopfloorwill assuremaximum efficiencyandadherencetodeliverydates. These notions appeared to be logical and were accepted without justification. However,subsequentresearchledtotheconclusionthatthesenotionsareinmany casesincorrect. Theterm‘best”routingisobscure;theroadmapmaygenerateover20routings foreachjob,eachonetoserveadifferentobjective. Using maximum production criterion of optimization routing for scheduling a random product mix showed that this criterion resulted in the longest throughput timecomparedtoothercriteria.Itwasnotacademicresearchbutitshedreasonable doubtsonthisnotion. Someresearchconclusionsonschedulingrulesindicatethat: • MeanflowtimeisminimizedbyusingSPTsequencingdispatchingrules. • MeaninventoryisminimizedbyusingSPTsequencingdispatchingrules. • Mean waiting time (prior to start processing) is minimized by using SPT sequencingdispatchingrules. • MaximumlatenessisminimizedbyusingSPTsequencingdispatchingrules. 2 SPTMeans: ShortestProcessing Time If SPT is so overwhelming in a particular setting, the routing can be designed to be composed of several short processing time elements instead of a few long operations. Anothermethodof keepingSPT is keepingbatchquantitylow.The quantityis definedineachspecificorder,butatleastoneshouldnotincreasethebatchquantity bycombiningjobsofotherorders. To summarizethe abovediscussion, some of the most importantall-embracing manufacturingtechnologynotionsforproductionplanningareasfollows: • Regardroutingasavariable. • Treateachorder,withitsproductstructure,individually. Preface ix • Convert a level-product structure into a working-product structure on a time scale. • The productwith the earliest start time of a lower levelitem is regardedas the criticalorder. • Give priorityto this criticalorderfor stock allocation(aftereach allocationthe criticalordermightbechanged. • Loadforprocessingeachorderasaunitratherthancombiningitems. • Releaseearlyscheduledperiodstoshopfloorforfurtherprocessing. Carryingouttheplanningactionsasdescribedabove,resultsin: • Minimumprocessingleadtime • Meetingdeliverydates • Maximumresourceutilization • Minimumworkinprocess • Minimumcapitaltiedowninproduction • Eliminationofbottlenecksinproduction 2.1 ShopFloorSchedulingandControl Theobjectiveofshopfloorplanningandcontrolistoensurethatthereleasedjobs foraperiodwillbecompletedontimeandinthemosteconomicalwaypossible.To achievethisgoal,totalflexibilityisrequired. The process spread sheet establishes a network of possible routings while deferring the decision of which path to take to a later stage. Furthermore, the decisionofwhichpathtotakecanbechangedaftereachtechnologicaloperation. Theproposedshopfloorcontrolapproachisbasedontheconceptthatwhenever a resource is free, it searches for a free operation to perform. A free resource is defined as a resource that has just finished an operation and the part has been removed, or is idle and can be loaded at any instant. A free operation is defined asanoperationthatcanbeloadedforprocessingatanyinstant.Anexamplewould bethefirstoperationofanitemforwhichtherawmaterialandalltheauxiliaryjobs areavailable,andiswithinreachoftheresourceloadingmechanism. 2.2 ManagementDecision SupportSystem All-embracingmanufacturingtechnologyisbasicallyanengineeringdrivensystem that creates a processing tool for the use of management. Its main feature is the abilitytogenerateroutingandschedulingonlinewithouttheneedforthepresence of a process planner during the processing; therefore, it may assist management bysupplyingobjectiveinformationandsimulationsneededtomakedecisionsfrom engineeringdata,suchas: • Resourceplanning • Acompany‘slevelofcompetitiveness x Preface • Improvementoflevelofcompetitiveness • Expansionofmanufacturingcapabilities • Introductionofnewmanufacturingtechnologies • Assistinginestablishingdeliverydates • Assistinginsettingoptimumsellingprices Any simulation the manager requires can be accessed by the appropriate computerprogram,withouttheneedtoconsultwithaprocessplanner. Thebookcontainssixchapters,whichpresentstwostagesofthemanufacturing process. The engineering stages of how to generate variable routing are presented in Chap. 1. The production planning stage is presented in Chap. 2. A system demonstrationisinChap.3. Themanagementstagesareregardedasinnovativetasksanddependondesigner creativity.Thereforetheyarenotconsideredaspartofthetechnology.Eachmanager maydirecthisorhercompanybyhisorherownmethodsandpreference. However,to demonstrate the benefits that one may acquire by appreciatingthe potentialofusingtheproposedtechnique,Chaps.4,5and6areincluded.
The list of books you might like
