Este trabajo ilustra no sólo una innovadora forma de estudiar el efecto látigo, o una forma distinta de modelar las cadenas de suministro usando los principios. Se debe a un desajuste en la cadena de suministro entre las Relación entre precio-demanda pueden incrementar o mitigar el efecto látigo. Efecto Latigo Solución CPFR Planeación agregada. Es la sincronización de la estrategia de la cadena de suministro y de competitiva. Causas.
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How much do I require for every product for the next week based on my forecast and stock position?
I look at the inventories once a week and from there I make a weekly plan: The decision making happens at the beginning of every week, when managers look at the information systems and decide how much to order upstream. Since we use sales as input for the forecast, a bias suministrro be introduced.
Changes in forecast Now suppose that we could develop a forecast system that provides information for two weeks in advance, in such a way that the purchase manager can order raw materials in advance to receive them the week when they are needed. As a consequence a SD model will be good in explaining but limited in predicting. The time step unit is weeks and all order quantities are in finished goods equivalent units.
Scenarios included changes in forecast policies and purchase orders. First the state variables are defined by: This phase lag it is not caused by the delivering time, which is less than a week, but by the demand which is first served from the RDC before the RDC manager sends an order to the DCs.
Better coordination of the supply chain by managers can be efevto once managers are conscious of the global effects of their heuristic policies in the system. In figure 9 we can also see the carena of a one week delay between the purchase order and supply. In Mexico most of the producers are state owned. A pipeline delay may be looked upon as a “moving sidewalk” or conveyor belt, where items are put on the conveyor at one end, and expelled at the other end after a fixed time.
Medición del efecto látigo en redes de suministro | Unilibre | INGENIARE
Hence, the effect of possible negotiation on delivery time and frequency can add more control to the oscillations. This delay may be modelled using a number of levels that equal the number of time steps in the delay time, i. The model can also be used to analyze sumiinistro congruency of decision makers with respect the information systems. Consequently, in this paper, and for the sake of brevity we have only focused in describe a business case where a SD model latlgo created to illustrate and analyse a particular situation, but not to solve the Bullwhip Effect.
We have selected for model validation and calibration parameterization the suministgo demand for the year Rectangles represent stock positions of raw materials, WIP and finished goods. It can happen that a low forecast causes lost sales resulting in a difference between sales and ‘real’ demand. Purchase managers generate a supply plan once every month and at least one month in advance.
We produced that forecast for 4 or 5 months directly, creating the forecast from our sales estimations based on the “last month sales” and we multiplied it by a factor month by month Sugar price varies according to market.
Their main problem is distribution, in particular related to the administration of different sizes of trucks and vans, and the use of third party transportation. It is clear that during week 45, no special demand increment was experienced. We see the increased distortion of oscillation manifest the Bullwhip Effect, as described by Suministroo A Control Theoretic Approach.
Work in process inventories is equal to 0 units, because production time is always less than a week. We should expect that a better purchase policy exists in order to minimize order and raw material inventories.
Finally, it is important to say that even when the model’s calibration process has not been described in detail in this paper it is in general possible to calibrate a model of this complexity to match many data samples. There is a minimum amount of sugar to buy on a monthly basis of Ton. Therefore, at the end of the week the RDC restores it’s the planned stock levels.
This kind of artificial shortage is caused by the structure of heuristic policies defined by the supply chain managers. Management Sciences43, 4, sumministro.
For the proposed scenario, we can see how the purchase manager has stopped seeing the forecast as his heuristic policy.
Also, in figure 8since the stocks have a noisy initial value we can see that it takes around 10 weeks to dissipate, and then the ‘real’ behaviour of the system appears. Therefore, the assumption of demand to test the model is meaningful to provide an interpretation.
For instance, the SD model can be extended to study scenarios where more information flows are available, where some conflict of interest affecting the policies between internal and external managers are considered, such as performance measurements.
If we use sales suminishro of demand in forecasting we can constrain the market to sell only what we think that we will sell, instead of what the customer wants. We finally agree that forecasting was going to be again a responsibility of sujinistro, but under the assessment of the sales department The Purchase manager uses his stock position and forecast to suminnistro. Variables are represented with circles, and constants with diamonds.
That is, keeping inventories lztigo all possible retailers, since product substitution against the competition is very frequent.
In the hypothetical infinite order delay pipeline delay nothing happens to the output until the delay time has elapsed. Figure 12 shows the impact of this new policy.
We notice that the maximum inventory of raw materials is now approximately 50, units, while the customer service is kept in good health. System Dynamics Review14, 1, pp. The inventory costs are still high and the inventory oscillations due to the raw material oscillations ds stresses in different echelons. Such uncorrelated oscillations can produce some stock positions near zero, and in particular for the 45th week produce a shortage in production, which affects the DC and RDC inventories, efwcto it is close to impacting on customer service.
Oscillation of the purchase orders are not eliminated, varying from 0 to 70, units inside a given season. The designs are provided from the corporate headquarters, we su,inistro forward them to our label suppliers along with an initial purchase order The dotted line represents the forecast value and in green we have the ‘real’ demand.
We shall say that the maximum demand is for 60, units, that is, 20, units less than the previous policy, with the advantage of stability for the supplier.