【正文】 manual logs ? affected by releases to shop, flow from prior operations ? Actual Output – Standard hours produced during each period ? from reporting systems or manual logs ? affected by resources, efficiency, workload 74 Definition ? Actual Queue – Begging (or prior period) queue + actual input actual output ? week ending 06/06: 300 + 197 213 = 284 ? verified periodically to confirm accuracy of input and output data ? Control – measure actual to plan ? actual output vs. planned output ? actual output vs. actual input ? actual input vs. planned input 75 Input/Output Comparisons ? Actual output ? planned output – Queues, LT ? – not enough input? Insufficient capacity? ? Actual output ? planned output – may run out of work, excess capacity ? Actual input ? planned input – may run out of work – feeding w/c behind schedule, late order 76 Input/Output Comparisons ? Actual input ? planned input – work released early, queue LT ? – feeding w/c ahead of schedule ? Actual output ? actual input – work released early, queue LT ? – not enough capacity ? Actual output ? actual input – work released late, may run out of work – feeding w/c behind schedule, idle capacity, late order 77 Dispatching Rules ? First e, first served (FCFS) ? Earliest Job Due Date (EDD) ? Earliest Operation Due Date (ODD) ? Operation start dates ? Critical ratios (CR) ? Shortest process time (SPT) ? Other methods Dispatching Rules D is p a tc h i ng R u leJ ob P roc e s sT i m e(da ys )A rri va lD a t eD ueD a t eO pe ra t i onD ue D a t eF C F S E D D ODD SPTA 4 223 245 2332 4 1 3B 1 224 242 2393 2 2 1C 5 231 240 2404 1 3 4D 2 219 243 2421 3 4 279 Capacity Management P la nningHo riz onExte nt T im eP eri odsDecisions T ec hniquesResou rceplanning(long ra ng e)Be y ondone y e arM onthl yQu art erl yY ea rl yP la nt constru ct ionEquipm ent P roc .M anpow er planni ngGr os sca lc u la t ionBO LOp era ti nghorizon p la n(m edium range)Up toone y e arW ee kl y M anpow er tra ns fe rsW ork pla n a d justm entsAlterna t e rou ti ngM ake /Bu yS ubcontrac t ingCapac i t yrequire m entsplanningExec ut ion(sh ort range)On e tofourweeksDail yW ee kl yOr der rel ea seOv ert im eAlterna t e rou ti ngOr der overl appingOp era ti onsequencingI/O c ontro l80 製造環(huán)境特性 特性 Job Shop Repetitive/Batch 產(chǎn)品定位策略 Maketoorder Maketostock Engineertoorder Assembletoorder 產(chǎn)量 低 高 批量 分?jǐn)?setup cost 1 Queue, move, wait time 高 (70% ~90%) 低 產(chǎn)能 Standard hours Cycle time Routings 變動(dòng) 固定 Dispatching 複雜 FCFS layout 功能別佈置 產(chǎn)品別佈置 SFC 推式 (push) 拉式 (pull) Reporting detail 高 低 81 製造環(huán)境 比較 OneofaKind Fixed location Fixed by job site Trucks, cranes Single product High Very long Satellites, construction Plant Organization Routing Material Handling Product Mix Amount WIP Time to Manufacture Examples Job Shop Variable by product Functional departments Fork lifts, tote bins Many products High Variable by product Tools, furniture Repetitive Fixed by assembly line Fixed by line Conveyors, containers Similar products Low Short Auto assembly, tires Flow Shop Fixed by plant Fixed by plant Conveyors, pipelines Similar products Low Short with long runs Oil, steel, cement Source: APICS, CPIM materials 1998 82 Conclusions ? Managing order LTs requires managing both priority and capacity ? Capacity plans should use the broadest possible product groups that go through similar manufacturing operations ? Capacity must be adequate to support the MPS and handle additional unplanned demands 83 ? 靜夜四無(wú)鄰，荒居舊業(yè)貧。 s: ave. service rate Activation = a/s 55 A Revised Definition of Capacity Available ? Capacity available = Time available ? Efficiency ? Availability ? Activation ? Availability – 1 the fraction of time down due to machine breakdown and/or absenteeism ? Activation – 1 the fraction of down due to lack of work UTILIZATION 56 How Load Is Determined? ? The production plan – long range rate of production ? The MPS drive MRP – MRP generate planned orders – released (open) orders ? CRP (capacity requirements planning) – calculates std hours required, by W/C, by time period, based on planned and open orders 57 Load Determination ? Open Orders (from order file status file maintained by production control) – order due date – order quantity – operations pleted – operation remaining ? MRPplanned Order Releases ( from MRP’ s output) – planned order release date – planned order receipt date – planned quantity 58 Data Requirements for CRP ? Valid due dates on all released and planned orders ? Uptodate routings and processing information ? Accurate standards for setup and processing time ? A scheduling pr