Single CNCmachineschedulingwithcontrollableprocessingtimes to minimizetotalweightedtardiness

Advancedmanufacturingtechnologies,suchasCNCmachines,requiresignificantinvestments,butalso offer newcapabilitiestothemanufacturers.OneoftheimportantcapabilitiesofaCNCmachineisthe controllableprocessingtimes.Byusingthiscapability,theduedaterequirementsofcustomerscanbe satisfiedmuchmoreeffectively.ProcessingtimesofthejobsonaCNCmachinecanbeeasilycontrolled via machiningconditionssuchthattheycanbeincreasedordecreasedattheexpenseoftoolingcost. Since schedulingdecisionsareverysensitivetotheprocessingtimes,wesolvetheprocessplanningand schedulingproblemssimultaneously.Inthisstudy,weconsidertheproblemofschedulingasetofjobs on asingleCNCmachinetominimizethesumoftotalweightedtardiness,toolingandmachiningcosts. We formulatedthejointproblem,whichisNP-hardsincethetotalweightedtardinessproblem(with fixed processingtimes)isstronglyNP-hardalone,asanonlinearmixedintegerprogram.Weproposeda DP-basedheuristictosolvetheproblemforagivensequenceanddesignedalocalsearchalgorithmthat usesitasabaseheuristic.