1、1Operations Scheduling Scheduling and Control Functions Job-shop Scheduling & Priority Rules Shop-floor Control Waiting Line Management2MPSMRP投日期 工單編號 工作內容 加工時間 交貨日期201 201 202 202 202 203 15131 15143 15212 15340 15312 15293 轉軸 100 栓 300 栓 100 鋼棒 150 轉軸 60 鋼棒 120 11.4 10.6 4.3 8.6 6.5 7.5 212 220 21
2、8 214 220 222 Production SchedulingShop Floor ExecutionManufacturing Execution SystemScheduling Process231. 指派工單、設備、人員 (short-run capacity planning)2. 安排工單處順序 (sequencing)3. 根據現場況釋出工單 (dispatching)4. 監控生產進與常況 (monitoring)5. 跟催工單程 (expediting)Scheduling and Control FunctionsShop Floor Control 準時交貨 me
3、eting due dates 低程時間minimize flow time (lead time) 低重置成本minimize set up time or cost 低在製品庫存minimize WIP inventory 提高人員/設備的使用 improve utilizationDo not try to maximize thisProcesses are either machine-limited or labor-limited4Job AssignmentTeam/MachineA B C D E05132I21212130V3205IV3012III4502IITeam/M
4、achineA B C D E38465I53455463V5427IV5234III8946IITeam/MachineA B C D E03132I21210130V1205IV1012III2502IITeam/MachineA B C D E02031I31310140V0104IV1022III1401IITeam/MachineA B C D E02031I31310140V0104IV1022III1401IIScheduling n jobs on m machines n=mWhat if nm or nm?35Forward and Backward Scheduling
5、Infinite Loading MRP is an infinite loading, backward scheduling system.Gantt chart6Priority rules 工單處優先法則 FCFS 先先處 SPT (SOT) 小工作先處 有效低平均程時間與現場庫存 EDD 交期早的先處 有效改善交貨延誤程 STR 寬放時間少的先處 寬放時間 (slack) =距交期天-工作所需天 Critical Ratio CR 值小的先處 CR =寬放天/距交期天 Random 隨意挑選 Sequencing and Priority RulesA good sequencing
6、 rule should be dynamic and based on slack.延誤程 Tardiness (lateness)、程時間 Flow time現場在製品庫存 WIP、人員與設備使用 Utilization 47到達順序 A B C D E 加工時間 3 4 2 6 1 交貨天 4 7 8 10 3 slack 1 3 6 4 2 FCFS 順序 程時間 延誤天 SPT 順序 程時間 延誤天 A 3 0 E 1 0 B 3+4=7 0 C 1+2=3 0C 7+2=9 1 A 3+3=6 2 D 9+6=15 5 B 6+4=10 3E 15+1=16 13 D 10+6=1
7、6 6 Average 10 3.8 Average 7.2 2.2 EDD 順序 程時間 延誤天 STR 順序 程時間 延誤天 E 1 0 A 3 0 A 1+3=4 0 E 3+1=4 1B 4+4=8 1 B 4+4=8 1 C 8+2=10 2 D 8+6=14 4D 10+6=16 6 C 14+2=16 8 Average 7.8 1.9 Average 8.6 2.8 Forward Scheduling, Finite Loading8Operation 1 Operation 2 A 3 2* B 6 8 C 5 6 D 7 4 從尚未安排之工單中選擇單站作業時間最短者 *
8、該站為第一站，安排該工單於最前的空位 該站為第二站，安排該工單於最後的空位 ? ? ? A 重複以上步驟直到所有工單均排入，總工作時間 (makespan)最短 ? ? D A C ? D A Johnsons rule for n/2 flow shopForward Scheduling, Finite LoadingExhibit 17.459Shop Floor Control1. Assigning priority of each shop order 2. Maintaining work-in-process information3. Conveying informatio
9、n to the office 4. Providing actual output data for capacity control purposes5. Providing quantity by location by shop order for WIP inventory and accounting purposes6. Providing measurement of efficiency, utilization, and productivity7. Data Integrity = Shop Discipline10Dispatching 確認工單之相關資訊，檢查工單所需
10、各項資源已經完備，根據現場況，控制訂單釋出的時機Anticipated Delay Report預期會延誤之訂單，查明原因並訂出因應措施Input/Output Control Report各單位實際生產進與預定生產進之差距Tools of Shop Floor Control611Principles of Work Center Scheduling work flow=cash flow 現場管制的效能取決於work flow的速 work flow的速取決於瓶頸機台的改善 減少插單，避免中斷進中的工作 儘低現場的確定性與突發況 排程配合各機台的每日實際進每日重新排程Exhibit 17
11、.912Scheduling Service Systems(1) Scheduling customers 以顧客為依據Appointment systems control the timing of customer arrivals.Reservation systems estimate demand for a given time period.How to deal with process delay, emergency, late arrivals, no shows?(2) Scheduling workforce and equipment 以資源為依據(3) Wai
12、ting Line Management 等候線管713Personnel Scheduling1. Forecasting Demand2. Convert into Workforce Requirements3. Convert into Daily or Weekly Work Schedules4. Assign Workers to Work SchedulesReceive Preprocess Microfilm Verify volume rate hours rate hours rate hours rate hours checks 2000 1000 2.0 600
13、3.3 240 8.3 640 3.1 statements 1000 600 1.7 250 4.0 150 6.7 notes 200 30 6.7 15 13.3 investments 400 100 4.0 50 8.0 200 2.0 150 2.7 collections 500 300 1.7 300 1.7 60 8.4 total hours 14.4 26.3 16.0 20.9 adjusted 18.0 32.9 20.0 26.1 staff required 2.3 4.1 2.5 3.3 Exhibit 17.1014Scheduling Hourly Work
14、 Times: First Hour Principle 10 11 12 1 2 3 4 5 6 7 8 9 Requirement 4 6 8 8 6 4 4 6 8 10 10 6 Assigned 4 On Duty 4 將人員需求反映至值班表26280 0 0 0 08 8 8 8 8484102100102132434A2132434forecastSunSatFriThuWedTueMon2121323B1120212C1110101DScheduling Consecutive Days Off Example 17.4815Waiting Line Management (T
15、N 7 p.289)服務完成QueuedisciplineArrival process排隊方式ServiceprocessRenegingBalking潛在顧客16Service Capacity vs. Waiting Line Trade-Off EX. TN7.1Cost of WaitingCostCost of CapacityService CapacityLargeSmallTotal Costminimum917Perceived Wait Time顧客認知的等候時間長等於實際等候時間對顧客滿意較有影響t*00.20.40.60.81perceived wait容忍界值敏感S
16、atisfactionActual Wait Time vs. Perceived Wait Time18等候的型公平與公平的等待舒適與舒適的等待可解與可解的等待有同伴與無同伴的等待等待高價值或低價值服務建設性與無建設性的等待主動與被動的等待Suggestions for Managing Queues1. 評估顧客願意接受的等侯時間長2. 轉移顧客的注意3. 提前告知顧客可能的況4. 讓顧客誤認服務人員怠職5. 將顧客分進服務6. 訓服務人員表現友善與關懷7. 鼓顧客使用峰時段8. Take a long term perspective.1019Multiple QueueTake a N
17、umber 3 4826 101211579多對多：應該排那邊？一對多 ：號碼牌制多對一：應該服務誰？ (traffic control)EnterSingle queueQueue Structure (number of lines)?20Queue Capacity (Limit)等候隊伍容影響顧客是否能夠加入排隊以及排隊情緒degree of patience到達後觀察即去 arrive, view, and leave (balking)排隊至中途才去 arrive, wait awhile, and leave (reneging) Queue Discipline 排隊規則Fir
18、st Come, First Served (FCFS, FIFO) 先先服務Shortest Processing Time (SPT) 小工作先服務Earliest Due Date (EDD) 先交件先服務Priority 預約或視潤高低Emergencies first 依緊急程而定1121 finite or infinite population 潛在顧客人多寡 stationary or unstationary 尖峰與峰時段 exponential interarrival times = Poisson process 顧客隨機到達!)()( )(neTnTPetfTnt=0
19、.000.050.100.150.200.250123456789100.000.100.200.300.400.500 5 10 15 20Customer Arrival Process22Service Process: single server, single phasePoisson到達速 ； 服務速 服務變性 2 System load = / 1model 1 (exponential service 2=(1/)2)model 2 (constant service 2=0)+=12W TimeWait 222qQueue Length Lq=WqSystem Time Ws
20、=Wq+1/Number in system Ls=WnnP=1model 1 only1223Service Process: Multiple servers, single phaseNumber in system Ls=Lq+ /Wait Time Wq=Lq/System Time W=Wq+1/Poisson到達速 ； 服務速 服務人員目 S (S)Model 3 (exponential service)Use = / and S to find Lqfrom exhibit TN7.11= 1LP(wait)qS24Conclusion Workflow equals cas
21、h flow. Scheduling lies at the heart of this process. Software packages are available to schedule jobs to determine bottlenecks and adjust job priorities. In services, the focus is on employee scheduling to meet expected customer demand. Waiting line management must balance the cost of waiting with the cost of adding more resources
