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1、Load-oriented manufacturing control just-in-time production for job shops,Production Planning Load conversion factor depreciation factor = planned output / Load limit = planning period planned lead time + planning period Limiting and balance work in process by order release.,Planned Inv. (I),(D),Loa
2、d limit,Planned lead time,Today,Planned Inv. (Buffer),Planned output(capacity),(D),Planned Release(I),Ideal Released Curve,Full load,Converted Load,Figure6. Derivation of conversion using the load limit,A considering the available capacities of a short-term planning periods(12Week) Planned orders we
3、re scheduled backward Selects periodically those of the planned orders Step1. Establish urgent orders Step2. Release wotrkable orders Time limit,3. Basic concept in load-oriented manufacturing control3.3 Technique of load-oriented order release,.,If capacities is needed Load-oriented release require
4、 appreciate decision,c,b,a,a,c,a,b,b,a,c,Planning period,Time limit,today,Time Days,Due,Over due,Future,Non-Urgent,Order 4,3,1,2,Workable,Workable,Unworkable,Omissible,A,B,C,Work centers,Load Hours,Load limit,Released Load,Remaining Load,Figure 7. Steps of Load-oriented order release,3. Basic concep
5、t in load-oriented manufacturing control3.4 Technique of load-oriented order entry,The ideas of Load-oriented order entry is to avoid overloaded weeks Checks the scheduled operation dates against available capacities for a midterm planning horizon (ex 12 weeks) Realistic due dates are offered and th
6、e expected bottlenecks are indicated. Initiation capacity changes in advance if possible Overload weeks Free date,.,.,Cumulative Load,Cumulative Capacity,Backlog,Overload Weeks,Underload weeks,Planning horizon,Today,Time week,Free Date,Overload Portion 83%,Total Load 100%,Load hour,Figure 8. Cumulat
7、ive load and capacity of a work center,.,. C is a critical work center,A,B,C,D,E,A,B,C,D,E,Overload Weeks,Today,Time week,Work center,A,B,C,D,E,Free Date,Order Lead Time,Operation Lead Time,Realistic Release Date,Realistic Delivery Date,Planning Horizon,Figure 9. Establishing a realistic delivery da
8、te of an order,4.Overview of a load-oriented manufacturing control system,1. Routing data 2. Order data 3. Item data 4. Shop calendar 5. Capacity data 6. Transaction data 7. Control data: detailed tables for w/c and free definable group,.,.,Shop Calendar,Capacity Data,Planning Data,Transaction Data,
9、Item Data,Order Data,Routeing Data,PROGRAM Transaction Data,PROGRAM Control Data,PROGRAM Shop Calendar,Program Graphs Reports,PROGRAM Operation Sequencing,PROGRAM Order Release,PROGRAM Order Entry,DIALOG Capacities,DIALOG Operation Complete,DIALOG Order Release,DIALOG Order Entry,Capacities Entries,
10、Capacities Release,Capacities Sequences,Graphs Reports,Control Data,CONTROL SYSTEM(PC),BASIC SYSTEM(HOST),PLANNING SYSTEM(PC),Figure 10. Load-oriented manufacturing control system showing the data flow,5.Example of the control system,1. The method of basic throughput diagrams is extended (Figure 1 w
11、ith diagrams) 2. Operation Throughput Element 3. Planned and actual average lead time are computed for each inventory as well as average due-date dev. For release, input, output and delivery,Entry,Release,Input,Output,Delivery,Disposition,Indirect,Direct,Downstream,Upstream,Open,Cycle,Total lead tim
12、e,Wait after operation,Transport,Wait before operation,Setup,Run,Interoperation time,Process time,Direct Load time,.,4. Pump-building factory characteristics products 9000 pumps Manufactured parts 26000 different items Manpower(Job shop) 180 persons Work centers 130 (mainly 2 shifts) Orders 350 per
13、week Operations 4,5 per order (Max 20) Run times 3,7 per operation Lot sizes 30 per order(1-1000) Factory began to work with the new system in 1987 Improvement (compared 1991 with 1987) Inventory was twice as high in 1987 Most delivery higher than in 1987 Cycle lead time(release delivery)were cut fr
14、om almost 8weeks to 5weeks Due-date deviations 4.5 to 1 week (lateness) Total lead time(entrydelivery) 14weeks to 9 weeks,Conclusion,Load-oriented manufacturing control system enables the factory 1. Reducing lead time and inventories 2. Keeping actual lead time on a planned level 3. Meeting the plan
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