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Production forecast and pre-production

Creator
Creator

Dear simulation experts,

 

I am modelling a Supply Chain and want to analyze it under certain conditions. One condition is the forecast of the production of the upcoming weeks including pre-production if possible.

I have attached the model. The conditions from the methods shall remain, but they shall be expanded by a condition of forecasting and pre-production.

And here is how this condition should work:

The weekly production capacity of the station "Produktion_Türen" is 389 parts per week. In some weeks there is still capacity left, in other weeks more parts than the given capacity shall be produced. So basically the weeks with a production higher than 389 shall be leveled. The amount of MUs that is above the capacity of 389 shall be produced earlier in a week with lower production. Only the parts "Türen" shall be pre-produced.

Here in more detail:

The forecast is 3 weeks. So if the company has capacities left in the current week the model shall look at the following 3 weeks (in the given tables). If in the following 3 weeks the aggregated, forecasted production of the two tables (WELT and GER) are higher than 389, this overcapacity shall be produced in the current week. This can mean the whole overcapacity is pre-produced or just a part of it (in case that else the current week exceeds 389 parts). The pre-produced parts must then be deleted in the week from where they were preponed.

 

To me this seems very complicated and I didn't find a proper way to model it.

I hope you can help me with it.

 

Best regards

Thomas

3 REPLIES

Re: Production forecast and pre-production

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor
basically you can reduce this problem to: when do you need to stop the production of doors; in theory you have a lot of approaches e.g. in German belastungsorientierte Auftragsfreigabe, Fortschrittszahlenkonzept...
in reality you have a limitation of interim storage place; to overbridge high demands, you will fill a buffer with doors up to a max. stock, when ever you will have time for this. In weeks with high demands, you will supply additional doors from the interim storage, in weeks with low demands you will fill up the stock...
A mathematical approach will fail, if you have to take into account quality, availabilities and so on.
The question remains: how big needs to be the interim stoage to fullfill the demands over a long period....
Steffen Bangsow
freelance simulation specialist  
web: www.bangsow.eu
mail: steffen@bangsow.net

Re: Production forecast and pre-production

Creator
Creator

Hello Steffen,

 

thank you for your reply.

Doesn't an interim storage mean higher production numbers for the same outcome? So when I have weeks with high demand I take out parts from the interim storage but still produce the orders from that week as soon as capacity is available (since the orders don't run out after a certain time) that means everything I pre-produced is produced twice after a certain time and I will build a constant interim storage.

 

In the model I have a really balanced demand of around 40 pieces. The supplier knows his capacities and by a demand forecast the production plan for the upcoming 4 weeks for the parts "Türen" as well as for the parts "Türen_WELT". In this case (excluding demand and prodcution variation), isn't it possible for the supplier to look in his production plan whether he will exceed his capacities in some of the next 4 weeks and shift the production of the parts "Türen" some weeks forward to when he has capacities left? That would mean a leveling of the production and if demand variation is excluded a better supply for the manufacturer without producing extra parts for the interim storage.

If so, how could I integrate that into the model? Maybe creating orders for the part "Türen" in weeks with undercapacities and delete the same amount of orders in weeks with overcapacities?

 

Best regards

Thomas

Re: Production forecast and pre-production

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

"Doesn't an interim storage mean higher production numbers for the same outcome? So when I have weeks with high demand I take out parts from the interim storage but still produce the orders from that week as soon as capacity is available (since the orders don't run out after a certain time) that means everything I pre-produced is produced twice after a certain time and I will build a constant interim storage."

 

I guess you misunderstand the concept of an interim storage. The interim-storage prevents over- and underutilization and failure events in a production. In each case you have a certain (limited) capacity. This is necessary for a leveling in several production steps. The interim storage is filled up to this level, then the production (upstream) stops (e.g. in case of customer problems). 

Practically in the model you will fill this interim storage at the initializing of the model and then the buffer stock will guarantee the supply of the next step under the moste conditions.

 

If you want to work with forecast data, you need to take into accout, that you need additional parts during the week of demand (and not weeks later). So you need to produce the additional demand at least one week before (and take it to a interim storage !!). This means, you need to change the production plan based on the forecast from the last week in the forecast in direction of the present week. To to this you will need to define a "freezing date" for the supplier (e.g. x+one week), and you will change the production planes depend on the forecast after each week until the "freezing date".

 

 

 

 

Steffen Bangsow
freelance simulation specialist  
web: www.bangsow.eu
mail: steffen@bangsow.net