Sistemas para mercado, producto.

4. Linkage between process choice and MPC system.

In order for a company to be successful, they must link the market requierments to process and then the process to MPC systems.
Three of the characteristics that Kochhar and McGarrie did, are related to the process, these are the number of manufacturing operations, the degree of cellular manufacturing and set-up time.  
Also, it is important that the MPC design must match the needs of the market, the manufacturing task and the  manufacturing process. Any change in this areas can produce a change in the MPC design, and there is intedependancy between MPC option choices and process choice features.

There are four characteristic of a process that may influence its performace, these are flow dominance, number of machines in each department, set-up time, and operation-time variance.

One of the main concepts is planning point which is a manufacturing resource, such as a work cell that can be regarded as one entity from a production and capacity planning point of view.
The process related issues can be condensed to : the number of planning points and set-up times. A set-up time is a key characteristic of a process itself, and the relevance about planning point is the number of them in a process.
Routing complexity, degree of flow orientation, number of manufacturing operations, and degree of cellular manufacturing can be all interpretated in terms of planning point.
The flow dominance is related to the number of bottlenecks.
The number of planning points tends to correspond to the number of departments, or the number of machines in each department.

5. Linking MPC system to markets, products and processes.

The choice of manufacturing process has a low impact at higher planning levels, but has a stronger link at lower levels.
The higher levels are more related to market, and the lower levels to the choice of manufacturing process.

The four levels on the MPC systems are:

• Sales and operation planning  (S&OP)
• Master production scheduling
• Requirements planning (material and capacity)
• Production activity control (shop-floor control)

The sales and operations planning level concerns volumen planning, and it is based on the market and product characteristics.  The variables that affect this level are demand patterns, product variety, comercial lead-times, among others. The main decisions in this level concern the groupings of product families, election of the planning strategy and aggregate production volumes.

Master scheduling  is related to the effective  use of available capacity, due to the fact that all process have limited capacity this leve is really important.
The more flow-oriented ths process is, the fewer the number of manufacturing steps.
In this level it is relevant to focus in the bottlenecks, because this can be the factor that allow the process to continue.

Requierments planning is a level where the factory becomes more real physically talking.
It deals with the acquiring the components needed to fulfil the Schedule, and the capacity in the internal and external supply system.
At this level, routings, set-ip and run times are introduced for all ítems and resources. A higher number of planning points and diverse routings among products makes a rate-based Schedule difficult to execute.

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