Question

Need Dates - what are they for?

J
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Hi,

Can somebody provide a detailed description of how Need Dates figure in production planning and MRP logic?

I posted something a while ago, but the answer didn't tackle my question.

I'd like something comprehensive i.e. how are they assigned, how can the be changed, what they actually reflect, and the role in CBS scheduling such as APB? 

 

Many thanks,

Jay

5 replies

eqbstal
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Jay,

My guess is that the question is to open. Please, for example, ask what a specific field does to the MRP.

Regards,

Steve

Please like this response if it helped you
J
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Hi,

 

It’s a specific field attached to supply items i.e. works orders, whether raised by MRP (through a requisition) or manually. 

 

How are they calculated? Can CBS (APB) change them, or does in only take them into account for backwards scheduling? what if the Need Date for the supply of a part is in the past, how does APB handle these objects?

 

These questions are general precisely because it’s a black box in terms of how it figures in offsetting and subsequent scheduling under APB constraints. 

 

I need some rough outline.

 

man thanks,

Jay

Saman K
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@JoherM 

//

It’s a specific field attached to supply items i.e. works orders, whether raised by MRP (through a requisition) or manually. 

 

How are they calculated? ( @Saman K   Basically the demand that trigger them decides the  need date then the lead time , if MRP is executed with the support of CRP then the routing information will be considered and the MRP planned need dated will be calculated )  Can CBS (APB) change them ( @Saman K  yes, they can , then planner has to reexecute MRP to plan shop order materials correctly again   ), or does in only take them into account for backwards scheduling? what if the Need Date for the supply of a part is in the past (  @Saman K  it will be in the pat because MRP calculate the supplies from the need date towards backwards)   , how does APB handle these objects? ( @Saman K  If these orders are scheduled they will come to present time as CBS or APB do not schedule operations before schedule start time  ( which is usually current time + some offset ) 

 

These questions are general precisely because it’s a black box in terms of how it figures in offsetting and subsequent scheduling under APB constraints. 

//

Hope this helps

@Saman K 

Saman K
J
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Hi Saman, 

 

This is a really lucid and detailed explanation that cuts to the heart of my confusion. I cannot thank you enough.

 

Regards, 

Jay

Saman K
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@JoherM 

Think of it this way..

You have a independent demand ( Customer order)

you release the CO- create the SO - the shop order need date will be based on the customer order wanted date.

then you run MRP. The need date of the SO is not changed. The shop order material required date will decide the finish date of the SOR of the component. ( generated by MRP) , when the planner releases the SOR a SO will be created and the need date will be finish date+ 1 day. That will not change after that. even if you replan it by CBS or APB or re run MRP. ( unless you manually change it or use some deliberate other actions to change it. ) 

I hope I missed that part in my reply.

/Saman

 

 

Saman K

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