Presentazione sul tema: "Chapter 6 Master Production Scheduling"— Transcript della presentazione:
1Chapter 6 Master Production Scheduling Vollmann, Berry, Whybark, Jacobs
2What is the MPS?The MPS translates the Sales & Operations Plan (SOP o PP) into a plan for producing specific products in the future.The MPS is the translation of the SOP into producible products that make up the output.
3At the operational level . . The MPS is developed to generate a sustainable Materials Requirement Planning (MRP) system and to provide the information for coordination with sales.The MPS is a statement of planned future output.
4As a statement of output, the MPS Forms the basic communication between the market and manufacturing.Is stated in product specification terms (part numbers) for which there are Bill of Materials (BOM).
5MPS can be stated in terms of? End-item product designationsOptions or modules from which a variety of end products could be assembled.Numbers of units of an “average” final product
6Conversion of MPS isControlled by a separate Final Assembly Schedule (FAS) which is defined at the very last moment.
7For the Make-to-Stock firm The items are produced in batches, carrying finished goods inventories for most, if not all, end-items.
8For the Make-to-Order firm In general, it carries no finished goods inventory and builds each customer order as needed.The MPS unit is defined as the particular end-item composing a customer order.Production often starts before a complete product definition or BOM has been determined.
9For the Assembly-to-order firm The MPS unit is typified by an almost limitless number of possible end-item configurations all made from combinations of basic components and subassemblies. Probably will not start final assembly until order arrives.
10Linkages to other firm activities It receives information from the SOP which in turn receives info from Demand Management (Forecasting) and resource planning.In addition it is linked to ERP (planning) and rough-cut capacity (make sure we can make it) planning.It generates information for MRP
11MPS TechniquesTime phased record (cadenza temporale delle previsioni per ogni item, con MPS livellato, di inseguimento o a lotti)Rolling through time (aggiornamento dell’MPS “lungo” la cadenza temporale)Order promising (ordini a consegna differita)Available to promise (ATP) (quanti ordini differiti posso accettareFigures 6.2; 6.3; 6.4 and 6.5
12Bill of Materials Structuring for the MPS It is an engineering document that specifies the ingredients (or subordinate components) required physically to make each part number or assembly.
13Single-level BOMComprises only those subordinate components that are immediately required (not the components of the components). Adatto per il MTS: make to stock, dove il MPS è specificato in termini di prodotto finale.
14Indented BOMIs a list of components, from the end item, down to the raw materials (it does show components of the components).
15Other definitionsBOM files are those computer records designed to provide desired output formats.BOM Structure relates to the architecture of the BOM filesBOM Processor is a computer software package that organizes and maintains linkages in the BOM as dictated by the BOM structure.
16More definitionsProduct Structure a company should have one and only one set of BOM records.Low-Level Code number should be designated for each part, component, subassembly or finished item in the BOM. These numbers indicate where in the product structure a particular item is with respect to the end item.
17Modular BOMWhen the combinations of end-item product are many ad esempio in una fabbrica automobilistica che produce grande varietà di prodotti finali, tenendo conto delle varie combinazioni di opzioni o moduli, it is better to use the MPS at the option or module level. The MPS is stated in the terms in which the product is sold not built. cioè in termini di BOM dei vari moduli della configurazione, ordinata dal clienteThe most widely used is called the super bill.(6.14) : la configurazione costituisce un single-level BOM che serve principalmente per la previsione di vendita (ma anche per montare il prodotto finale); nel super-bill ogni opzione è pesata con la media della sua presenza nelle configurazioni prodotte (se si vendono 1000 auto con 2 porte e 500 con 4 porte, la media è 8/3). Il SOP/PP e l’MPS si fanno allora in termini di super bill. Le medie del super-bill sono valide nel lungo periodo e vengono assorbite nel breve periodo da Safety Stock dei singoli moduli. I livelli dei Safety S. sono mantenuti dall’MRP.
18Final Assembly Schedule (FAS) fig. 6.17-6.18-6.19 FAS job is to convert MPS records into FAS records as we roll through time. (6.17)La configurazione finale è gestita con il FAS secondo un principio pull: dall’ordine si risale alla configurazione e si accetta l’ordine (eventualmente differito) se sono (o saranno) disponibili i componenti; quindi parte l’ordine di eventuale loro finitura e l’assemblaggio finale. In sostanza i componenti sono prodotti make-to-stock e il finale assembly-to-order.Tutto ciò va bene per produzioni ripetitive a numerosità medio-alta o al più media (ricordare il diagramma). Quando la numerosità è più bassa ci può essere la variante che componenti non disponibili, necessari ad accettare un ordine, vengono inseriti, con una variante, nell’MPS di produzione dei componenti.
19The Master Production Scheduler Its useful to think of the MPS as a set of firm planned orders. The scheduler needs to convert planned orders to firm planned orders and to manage the “timing” and amounts of the firm planned orders.
20The Job of the Master PSPrimary responsibility for making any additions or changes to the MPS records.Has also has responsibility for disaggregating the production plan to create the MPS and that the sum of the detailed MPS matches the Production Plan (SOP).
21The Job of the Master PS Responsible for launching the FAS. Making sure that there is only one unified database for the MPSMeasure actual performance against the MPS and production plan (SOP)
22Conflitto tra B e C in sett 8 effettivo 50 previsto To production 150
23MPS StabilityA stable MPS translates into stable component schedules, which means improved performance in plant operations.Too many changes – lower productivityToo few changes – lower customer service levels.
24Increasing MPS stability Stability is monitored and managed by:Frozen time periods for the MPS andTime fencing to establish clear guidelines for the kinds of changes that can be made.
25Frozen ScheduleThis means that for the more recent time buckets it will be very difficult (but still negotiable) to change the sequence in which the orders will be processed.
26Time Fencing This is an extension of the freeze concept. Many companies set time fences that specify periods in which various types of change can be handled.In the Demand fence the forecast is ignored in calculating the available (difficult to change the MPS).The planning fence indicates the time at which the scheduler should be planning more MPS quantities. per consentire “management trade-off to make changes”
27Managing the MPS Start by having a realistic MPS Stability and proper buffering are important to remove all the excuses for not attaining the performance for which the proper budget has been provided.6.24