企業(yè)資源計(jì)劃原理與實(shí)踐章物料需求

2024/2/221第六章物料需求計(jì)劃2024/2/2226.1MRP定義與作用物料需求計(jì)劃（MaterialRequirementPlanning，簡稱為MRP）是對主生產(chǎn)計(jì)劃的各個項(xiàng)目所需的全部制造件和全部采購件的數(shù)量需求計(jì)劃和時(shí)間進(jìn)度計(jì)劃。物料需求計(jì)劃物料需求物料庫存2024/2/223主生產(chǎn)計(jì)劃粗能力計(jì)劃MRPII邏輯流程圖

產(chǎn)品規(guī)劃資源需求計(jì)劃銷售規(guī)劃可行？可行？物料需求計(jì)劃能力需求計(jì)劃可行？采購作業(yè)車間作業(yè)成本會計(jì)業(yè)績評價(jià)資源清單合同預(yù)測其它需求供應(yīng)商信息銷售與運(yùn)作計(jì)劃應(yīng)收帳總帳應(yīng)付帳庫存信息物料清單工作中心工藝路線客戶信息成本中心會計(jì)科目宏觀微觀經(jīng)營規(guī)劃123454個計(jì)劃層次1個執(zhí)行層次決策層

計(jì)劃層

執(zhí)行控制層2024/2/224MRP的基本思想圍繞物料轉(zhuǎn)化組織制造資源，實(shí)現(xiàn)按需要準(zhǔn)時(shí)生產(chǎn)。按反工藝順序確定需求數(shù)量和時(shí)間復(fù)雜的計(jì)算，計(jì)算機(jī)技術(shù)的發(fā)展促進(jìn)了實(shí)現(xiàn)為什么要圍繞物料轉(zhuǎn)化組織生產(chǎn)圍繞物料：按需生產(chǎn)圍繞設(shè)備：以產(chǎn)定銷拖期完工、提前完工不配套、過量生產(chǎn)2024/2/2252024/2/226MRP與訂貨點(diǎn)方法的區(qū)別盲目性高庫存與低服務(wù)水平如需5種零件,當(dāng)以95％的服務(wù)水平供給每種零件時(shí)，每種零件的庫存水平會很高5種零件都不發(fā)生缺貨的概率僅為(0.95)5=0.774形成“塊狀”需求周次12345678910情況12000200002000情況2200400000000情況32000000000402024/2/227塊狀需求2024/2/228要生產(chǎn)什么?(根據(jù)MPS)；要用到什么?(根據(jù)物料清單)；已經(jīng)有了什么?(根據(jù)庫存信息)；還缺什么？何時(shí)訂貨？(MRP運(yùn)算后提出的報(bào)告)。MRP要回答4個問題2024/2/2296.2MRP的相關(guān)概念制造/采購標(biāo)識碼P:某物料是采購件M:某物料是制造件。損耗率組裝廢品系數(shù)：裝配件在裝配過程中的零件損耗。裝配產(chǎn)品A時(shí)，估計(jì)有5%的玻璃管毀壞，因此在計(jì)算A所需的玻璃管的毛需求時(shí)，要增加組裝時(shí)的損耗部分，如裝配100件A的訂單要有100*105%=105個玻璃管部件的需求2024/2/2210零件廢品系數(shù)：對于一定數(shù)量的訂單，預(yù)計(jì)入庫時(shí)，會有一定百分比的減少，零件廢品系數(shù)是對訂單數(shù)量而不是對毛需求的調(diào)整。產(chǎn)品A入庫時(shí)的零件廢品系數(shù)為2%，在組裝時(shí)的組裝廢品系數(shù)為5%，針對該需求制定MRP時(shí)，首先考慮2%的零件廢品系數(shù)，計(jì)算產(chǎn)品A的計(jì)劃訂單數(shù)，計(jì)劃訂單數(shù)量要比需要的多2%，如A需求為100時(shí)，訂單應(yīng)為102；然后根據(jù)計(jì)劃訂單數(shù)量再考慮組裝A時(shí)的組裝廢品系數(shù)，在這種情況下，A項(xiàng)目的102的訂單對玻璃管的毛需求量應(yīng)為102*105%=108。材料利用率是有效產(chǎn)出與總輸入的比率，即：材料利用率=有效產(chǎn)出/總投入某裝配件的材料利用率是95%，那么為了要100件的產(chǎn)品就要投入生產(chǎn)(100/95%=105.3≈16)個產(chǎn)品的裝配件2024/2/22116.3MRP的編制處理的問題需要信息1.生產(chǎn)什么？生產(chǎn)多少？何時(shí)完成？1.現(xiàn)實(shí)、有效、可信的MPS2.要用到什么？2.準(zhǔn)確的BOM，實(shí)時(shí)的設(shè)計(jì)更改通知3.已有什么？已訂貨量？到貨時(shí)間？已分配量？3.準(zhǔn)確的庫存信息，下達(dá)訂單跟蹤信息，配套的領(lǐng)料單、提貨單4.還缺什么？4.批量規(guī)則、安全庫存、成品率5.下達(dá)訂單的開始日期？5.提前期2024/2/2212MRP的編制過程(1)計(jì)算物料的毛需求量毛需求量＝物料的獨(dú)立需求量+父項(xiàng)產(chǎn)生的相關(guān)需求量(2)計(jì)算凈需求量凈需求量=毛需求量+安全庫存量-計(jì)劃接收量-可用庫存量可用庫存量=現(xiàn)有庫存量-已分配量(3)計(jì)算計(jì)劃完工量(N-1)×固定批量<凈需求<N×批量固定(4)計(jì)算計(jì)劃投入量(5)根據(jù)計(jì)劃完工和計(jì)劃投入，產(chǎn)生計(jì)劃訂單。2024/2/22132024/2/2214CooperstownCars,Inc.ProducestoycarsBodyAxles(2)Wheels(4)2024/2/2215CooperstownCars,Inc.-Eachcomponenthasaknownleadtime2024/2/2216CooperstownCars,Inc.Scheduleproductionfor:ToycarassemblyWheelassemblyBodyAxleWheelsDemandforToyCarinWeek8is1002024/2/2217Time-PhasedProductStructure1weekToyCarTimeinWeeks456782024/2/2218Time-PhasedProductStructure1week1weekToyCarWheelAssemblyBody2weeks45678TimeinWeeks2024/2/2219Time-PhasedProductStructure1week1weekToyCarWheelAssemblyBodyAxlesWheels2weeks1week2weeks45678TimeinWeeks2024/2/222012345678ToyCarRequiredDate100OrderreleasedataWheelassemblyRequiredDateOrderreleasedataBodyRequiredDateOrderreleasedataAxleRequiredDateOrderreleasedataWheelsRequiredDataOrderreleasedataWeekGrossRequirementsPlan2024/2/222112345678ToyCarRequiredDate100Orderreleasedata100WheelassemblyRequiredDateOrderreleasedataBodyRequiredDateOrderreleasedataAxleRequiredDateOrderreleasedataWheelsRequiredDataOrderreleasedataWeekGrossRequirementsPlan2024/2/222212345678ToyCarRequiredDate100Orderreleasedata100WheelassemblyRequiredDate200OrderreleasedataBodyRequiredDateOrderreleasedataAxleRequiredDateOrderreleasedataWheelsRequiredDataOrderreleasedataWeekGrossRequirementsPlan2024/2/222312345678ToyCarRequiredDate100Orderreleasedata100WheelassemblyRequiredDate200Orderreleasedata200BodyRequiredDateOrderreleasedataAxleRequiredDateOrderreleasedataWheelsRequiredDataOrderreleasedataWeekGrossRequirementsPlan2024/2/222412345678ToyCarRequiredDate100Orderreleasedata100WheelassemblyRequiredDate200Orderreleasedata200BodyRequiredDate100OrderreleasedataAxleRequiredDateOrderreleasedataWheelsRequiredDataOrderreleasedataWeekGrossRequirementsPlan2024/2/222512345678ToyCarRequiredDate100Orderreleasedata100WheelassemblyRequiredDate200Orderreleasedata200BodyRequiredDate100Orderreleasedata100AxleRequiredDateOrderreleasedataWheelsRequiredDataOrderreleasedataWeekGrossRequirementsPlan2024/2/222612345678ToyCarRequiredDate100Orderreleasedata100WheelassemblyRequiredDate200Orderreleasedata200BodyRequiredDate100Orderreleasedata100AxleRequiredDate200Orderreleasedata200WheelsRequiredDataOrderreleasedataWeekGrossRequirementsPlan2024/2/222712345678ToyCarRequiredDate100Orderreleasedata100WheelassemblyRequiredDate200Orderreleasedata200BodyRequiredDate100Orderreleasedata100AxleRequiredDate200Orderreleasedata200WheelsRequiredData400Orderreleasedata400WeekGrossRequirementsPlan2024/2/22282024/2/22292024/2/22302024/2/22312024/2/22322024/2/22332024/2/22342024/2/22352024/2/22362024/2/22372024/2/22382024/2/22392024/2/22402024/2/22412024/2/2242Morecomplexity/ScheduledreceiptsExplanation:Grossrequirementsarethetotaldemandforwheels.Projectedon-handinventoryinweek1is30+200–1502024/2/2243Morecomplexity/ScheduledreceiptsProjectedon-handinventorybalanceatendofweektInventoryonhandatendofweekt-1GrossrequirementsinweektScheduledorplannedreceiptsinweekt=+–2024/2/2244Morecomplexity/Scheduledreceipts12345678WheelsGrossrequirements150120150120Scheduledreceipts200Projectedon-hand|30808080PlannedorderreceiptsPlannedorderreleasesNetRequirementsPlanWeek2024/2/2245Leadtime=1week12345678WheelsGrossrequirements150120150120Scheduledreceipts200Projectedon-hand|30808080PlannedorderreceiptsPlannedorderreleasesNetRequirementsPlanWeekLot-SizingRules:L4LL4L-ordertheamountneededtofulfillrequirements2024/2/2246Lot-SizingRules:L4LLeadTime=1week12345678WheelsGrossrequirements150120150120Scheduledreceipts200Projectedon-hand|30808080Plannedorderreceipts40Plannedorderreleases40NetRequirementsPlanWeek2024/2/2247Lot-SizingRules:L4LLeadTime=1week12345678WheelsGrossrequirements150120150120Scheduledreceipts200Projectedon-hand|30808080000Plannedorderreceipts40150Plannedorderreleases40150NetRequirementsPlanWeek2024/2/2248LeadTime=1week12345678WheelsGrossrequirements150120150120Scheduledreceipts200Projectedon-hand|308080800000Plannedorderreceipts40150120Plannedorderreleases40150120NetRequirementsPlanWeekLot-SizingRules:L4L2024/2/2249Lot-SizingRules:EOQEOQ-ordertheEOQLeadtime=1week12345678WheelsGrossrequirements150120150120Scheduledreceipts200Projectedon-hand|30808080PlannedorderreceiptsPlannedorderreleasesNetRequirementsPlanWeek2024/2/2250Leadtime=1week12345678WheelsGrossrequirements150120150120Scheduledreceipts200Projectedon-hand|30808080Plannedorderreceipts116Plannedorderreleases116NetRequirementsPlanWeekLot-SizingRules:EOQEOQ-ordertheEOQ2024/2/2251Lot-SizingRules:EOQEOQ-ordertheEOQ80=76Leadtime=1week12345678WheelsGrossrequirements150120150120Scheduledreceipts200Projectedon-hand|308080807676Plannedorderreceipts116Plannedorderreleases116NetRequirementsPlanWeek2024/2/2252Leadtime=1week12345678WheelsGrossrequirements150120150120Scheduledreceipts200Projectedon-hand|308080807676Plannedorderreceipts116116Plannedorderreleases116116NetRequirementsPlanWeekLot-SizingRules:EOQEOQ-ordertheEOQ2024/2/2253Leadtime=1week12345678WheelsGrossrequirements150120150120Scheduledreceipts200Projectedon-hand|30808080767642Plannedorderreceipts116116116Plannedorderreleases116116116NetRequirementsPlanWeekLot-SizingRules:EOQEOQ-ordertheEOQ2024/2/2254Lot-SizingRules:EOQEOQ-ordertheEOQLeadtime=1week12345678WheelsGrossrequirements150120150120Scheduledreceipts200Projectedon-hand|308080807676423838Plannedorderreceipts116116116Plannedorderreleases116116116NetRequirementsPlanWeek2024/2/2255物料需求計(jì)算(逐級展開)XA(1)C(2)O(1)C201010A1010O提前期=2提前期=1提前期=1批量=40批量=1批量=1X提前期=1批量=1時(shí)段計(jì)劃投入量計(jì)劃產(chǎn)出量123456789101112現(xiàn)有量=0時(shí)段計(jì)劃投入量計(jì)劃產(chǎn)出量123456789101112現(xiàn)有量=0現(xiàn)有量=0時(shí)段計(jì)劃投入量計(jì)劃產(chǎn)出量123456789101112計(jì)劃接收量現(xiàn)有量=50時(shí)段計(jì)劃投入量計(jì)劃產(chǎn)出量123456789101112計(jì)劃接收量毛需求凈需求預(yù)計(jì)庫存量10101010101010105101010101010105101010102020202010202020201010202020203030510101030(40)50404030301010004040MPSMRP加工計(jì)劃采購計(jì)劃(40)2024/2/2256多個產(chǎn)品MRP運(yùn)算A(1)C(2)C(1)Y毛需求計(jì)劃接收量庫存量(前)庫存量(后)凈需求計(jì)劃產(chǎn)出量計(jì)劃投入量毛需求計(jì)劃接收量庫存量(前)庫存量(后)凈需求計(jì)劃產(chǎn)出量計(jì)劃投入量MPS

計(jì)劃產(chǎn)出量MPS

計(jì)劃投入量MPS

計(jì)劃產(chǎn)出量MPS

計(jì)劃投入量批量提前期現(xiàn)有量分配量安全庫存低層碼物料號1111122220000000000XXYCA504051015當(dāng)期110-50552010-100001010101010101010202020202020202023456785515150020-200202010001055535353050555550555560-545155050454540555550555555555555

時(shí)段2/032/102/172/243/033/103/173/242024/2/2257為什么要先有主生產(chǎn)汁劃，再根據(jù)主生產(chǎn)計(jì)劃來制定物料需求計(jì)劃？2024/2/2258MRP系統(tǒng)有兩種基本的運(yùn)行方式：主生產(chǎn)計(jì)劃的變化、產(chǎn)品結(jié)構(gòu)的變化，以及計(jì)劃因素的變化。全重排式：系統(tǒng)將整個主計(jì)劃進(jìn)行分解，結(jié)合庫存在手量，求出每一物料按時(shí)間分解的需求數(shù)據(jù)。需遍歷所有最終需求、BOM文件。凈改變式：一是每次運(yùn)行系統(tǒng)時(shí)，都只需要分解主生產(chǎn)計(jì)劃中的一部分內(nèi)容；二是由庫存事務(wù)處理引起的分解只局限在該事務(wù)處理所直接涉及到的物料項(xiàng)目及其下屬層次上的項(xiàng)目。6.4計(jì)劃運(yùn)行的方法2024/2/2259全重排式需要大量的時(shí)間運(yùn)行，所以只能以定期（如一周，半月）的時(shí)間間隔運(yùn)行。但處于此間隔中間的需要無法及時(shí)得到反應(yīng)。在一個BOM和需求變動頻繁的具體環(huán)境中這個問題顯得特別嚴(yán)重。全重排式2024/2/2260凈改變法式MRPII系統(tǒng)具有實(shí)用價(jià)值的關(guān)鍵。將變化部分的需求進(jìn)行局部分解，以較短的時(shí)間（如每天）運(yùn)行，能迅速應(yīng)對變化的環(huán)境。副作用在于：系統(tǒng)的自清理能力較差數(shù)據(jù)處理的效率相對比較低系統(tǒng)對變化過于敏感對策：讓系統(tǒng)總是給出最新信息；根據(jù)系統(tǒng)提供的新信息，以適當(dāng)?shù)念l度采取行動。采購員不立即采取行動，但必需密切關(guān)注這些新信息。即人為地抑制過度系統(tǒng)敏感性。全重排式2024/2/2261以天為間隔運(yùn)行凈改變MRP，并處理庫存事務(wù)。定期（取決于企業(yè)具體生產(chǎn)環(huán)境和主計(jì)劃編制方法）輔以全重排法以對系統(tǒng)進(jìn)行數(shù)據(jù)清理。設(shè)計(jì)凈改變和全重排方法及他們運(yùn)行的時(shí)間間隔是MRPII系統(tǒng)設(shè)置需考慮的一個重要參數(shù)。比較可行的計(jì)劃方法2024/2/22626.5MRP與其他模塊的關(guān)系2024/2/2263模型（超級）BOM模型物料清單定義了選項(xiàng)清單和選項(xiàng)類，指定了法定組件，您可以在銷售模塊中選擇以訂購配置。模型清單可以是按訂單裝配或按訂單挑庫類型的EGA顯示器計(jì)算機(jī)VGA顯示器顯示器VGA真彩色VGA-AVGA標(biāo)準(zhǔn)VGA-B模型BOM不可選標(biāo)準(zhǔn)BOM可選選項(xiàng)類BOM可選標(biāo)準(zhǔn)BOM可選標(biāo)準(zhǔn)BOM可選標(biāo)準(zhǔn)BOM可選標(biāo)準(zhǔn)BOM可選選項(xiàng)類BOM不可選2024/2/2264電子掛鐘機(jī)芯花紋1花紋2花紋2花紋1紅黑電池特征件與可選件鐘盤指針盤面秒針

短針長針鐘框塑料(紅)塑料(白)塑料(金)金屬(壓花）金屬(平)木雕(鷹)木雕(屋)木雕(輪)配不配金白黑金通用件特征件（基本組件）可選件（必選其一、可選其一）2024/2/2265電子掛鐘字型2鐘框塑料木雕鷹屋紅白凸平通用件機(jī)芯鐘盤黑色金色字型1字型1字型2指針花紋1花紋2長針花紋2花紋1

短針

秒針紅

黑電池可選件(1.0)(1.0)(1.0)(1.0)(0.5)(0.5)(0.2)(0.2)(0.3)(0.3)(0.3)(0.3)(0.1)(0.1)(0.1)(0.1)金屬(0.2)(0.2)(0.6)(1.0)(1.0)(1.0)(0.5)(0.5)(0.5)(0.5)(0.5)(0.5)(1.0)注：括號內(nèi)為預(yù)測百分比(0.5