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Repetitive Manufacturing Framework & Capacity Analysis

Repetitive Manufacturing Framework & Capacity Analysis. Factory Automation Lab. SNU. May. 21. 1999 Min, Dai ki. Contents. Introduction What is Repetitive Manufacturing ? Framework Characteristics REM in SAP R/3 Capacity Analysis Model. Introduction.

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Repetitive Manufacturing Framework & Capacity Analysis

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  1. Repetitive ManufacturingFramework & Capacity Analysis Factory Automation Lab. SNU. May. 21. 1999 Min, Dai ki 1 / 29

  2. Contents • Introduction • What is Repetitive Manufacturing ? • Framework • Characteristics • REM in SAP R/3 • Capacity Analysis Model 2 / 29

  3. Introduction • Repetitive Manufacturing(REM) greatly differ from those of intermittent manufacturing. • One of the most common problem was the use of MRP software packages for REM…(Hall, 1982) • There are still very few researches for the production planning in REM environment. • Review the REM framework and Consider the production planning factors in the REM environment 3 / 29

  4. What is REM ?The definitions • Repetitive manufacturing(REM) is a form of manufacturing where various items with similar routings are made across the same process whenever production occurs. Products may be made in separate batches or continuously. Production in a repetitive environment is not a function of speed or volume. (APICS Repetitive Manufacturing SIG) • Repetitive Manufacturing is the production of discrete units in a highly volume concentration of available capacity using fixed routings. Products may be standard or assembled from standard modules. Production management is usually based on the production rate. (M.S. Spencer & J.F.Cox III) 4 / 29

  5. What are the characteristics of REM ? • Production tends to be continuous, rather than in discrete lots. (lot identity does not exist) • Items flow through the production process on a relatively fixed routing. (focus on the production line) • Production may be to a schedule rather than to specific manufacturing orders. • Planners control production by volume produced over time. • Internal lead time tend to be relatively short, once the basic production line has been set up. 5 / 29

  6. What are the characteristics of REM ? • In-line processing is common. (production is performed simultaneously) • Shop floor progress can be reported at some points only. • Work-in-Process tends to be smaller. These parameters require a different approach to Manufacturing Planning and Control. 6 / 29

  7. What is the differencebetween REM & Job Shop ? Comparison of job shop and repetitive shop (Handbook of Material & Capacity Requirement Planning p.272) 7 / 29

  8. What techniques are used by REM ? • Backflushing for material • Rate-based scheduling • Flattening bill of materials • Visual manufacturing techniques ( ex) planning table in R/3) 8 / 29

  9. What are the steps to repetitive scheduling? • Verify production line model mix • Synchronize schedule with flow rate of production line • Create repetitive schedule for specified period • Use repetitive transfer pick_list • Report at milestones • Maintain and close orders. (APICS Repetitive Manufacturing SIG) 9 / 29

  10. Repetitive Manufacturing Model MPS & CAPACITY LINE RATE VOLUME COCENTRATION • MRP is the framework necessary to provide the communications link from the planning function to the supplier base. ( The role of MRP in repetitive manufacturing, M.S. Spencer & J.F. Cox, IJPR., 1995, vol. 33, p.1891 ) PLANNING PRIORITY PLANNING METHODS MRP JIT TOC SHOP FLOOR CONTROL PRIORITY & CAPACITY CONTROL 10 / 29

  11. REM in SAP R/3 Demand • Process Scheduling Agreement (SD) Post Goods Issue Create Delivery Create Transfer Order Billing Planning Table for REM Carry out dependent MRP Sales Plan Create REM Backflush Work Result Create Transfer Order for Production 11 / 29

  12. REM in SAP R/3 Material Mater • Structure • Production Version : data relevant to the production process. • Run Schedule Header : general information for the production of a product. • Run Schedule Quantity : planning quantities. Production Version1 Production Version2 RS header for VS3 Production Version3 Describes the production procedure Product Version Validity Period storage location Assign copied Run Schedule Quantities Routings BOMs Work Centers 12 / 29

  13. REM in SAP R/3 • Orderless production using run schedule quantities • Period-based planning based on production-rate • Assigning run schedule quantities to production lines • Simplified capacity planning • Available capacity display • Quantity changes with interactive calculation of the capacity load smooth over/under loads by user • Backflushing based on quantities 13 / 29

  14. Capacity analysis in repetitiveassemble-to-order manufacturing systems F. Fumero, C. Vercellis Dipartmento di Economia e Produczione, Politecnico di Milano, Italy EJOR Vol. 78, 1994. pp. 204-215. 14 / 29

  15. Contents • The ATO production environment • Capacity planning and Multi Layered Modeling • Capacity planning model for ATO environment • Model decomposition algorithm 15 / 29

  16. The ATO environment • ATO : a hybrid between MTS and MTO • new problems arise concerning the integration between two stages regulated by different rules. • In the ATO environment the capacity planning models should allow to evaluate the various performances. • service level • flexibility • productivity • with focus on control levels which are responsible of the lead times. 16 / 29

  17. Capacity planning andMulti Layered Modeling • Analytic approach based on queuing theory : excessively restrictive assumptions which are rarely fulfilled in practice • Simulation models : become too complex and impractical • Optimization models : provide more active support to decision makers. 17 / 29

  18. Capacity planning andMulti Layered Modeling • Aggregate planning may be regarded as a way to overcome the practical limitations divide and conquer approach • Hierarchical Production Planning(HPP) approach suffers from the drawback of missing the bottom up links. • Multi Layered Modeling(MLM) : based on Lagrangean relaxation techniques, bi-directional information flow among the hierarchical levels. 18 / 29

  19. Capacity planning model for ATO Transportation (1) Backordering (2) Inventory of Subassemblies (3) Extra-quantities of the different production resources and equipment (4) 19 / 29

  20. Capacity planning model for ATO Aggregated production volume (5) Transportation Quantities (6) Inventory level (7) Aggregated component quantities (8) 20 / 29

  21. Capacity planning model for ATO (9) (10) (11) (12) (13) (14) 21 / 29

  22. Capacity planning model for ATO (15) (16) (17) (18) (19) (20) (21) 22 / 29

  23. Capacity planning model for ATO (22) (23) (24) 23 / 29

  24. Lagrangean decomposition algorithm (25) • Lagrangean multipliers to the consistency conditions (5), (6), (7), (8), (25), respectively: • We obtain a dual problem in the form: (26) 24 / 29

  25. Lagrangean decomposition algorithm • F1 : interplant planning ; splitting of the end-items production among the different plants, according to the available resources and with an aggregate check of demand fulfillment. • Balance equations at an aggregate level: (27) (28) (29) (30) 25 / 29

  26. Lagrangean decomposition algorithm (31) Subject to (15), (27), (28), (29) and (30) • F2: Families disaggregation. ;demand fulfillment is verified more carefully • considering the specific end-items, instead of their families. (32) Subject to (9), (10), (11), (12) and (16) 26 / 29

  27. Lagrangean decomposition algorithm F3: Subassemblies planning. ; fulfillment of internal and external demand and verifying general resources availability and inventory bounds (33) Subject to (13), (14), (17) and (22) F4: Routing Choice. ; split the production volume among the different types of machines, verifying the availability of resources. (34) Subject to (18) 27 / 29

  28. Lagrangean decomposition algorithm • F5 : Lot-sizing: the weekly production plan is arranged by fixing the lot-size for each subassembly. (35) Subject to (19), (20), (21), (23) and (24) 28 / 29

  29. References • Capacity analysis in repetitive assemble-to-order manufacturing systems, F.Fumero, C. Vercellis, EJOR. vol. 78(1994), pp204-215 • Repetitive manufacturing planning and control systems: a framework for analysis, Alberto de toni and Roberto panizzolo, PPC. Vol. 8(1997), pp500-508 • The role of MRP in repetitive manufacturing, M. S. Spencer and J.F.Cox III, IJPR. Vol.33(1995) pp.1881-1899 • Handbook of M&CRP, Howard W. Oden, McGraw-Hill • http://www.apics.org • http://www.nissi.co.kr 29 / 29

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