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Hi,

I don't fully understand the date logic in the time-phased supply proposals created by IFS for an end-item (in an engineer-to-order setting).

Can you outline the key types of dates (or 'offsetting inputs') that figure within scheduling. From specifying when the user desires said item, to all the subsequent dates that are generated after BoM explosion. The 'tools' at are disposal are IFS Apps 10, namely, MRP that executes 'Infinite Scheduler' and 'APB' (our method to CBS schedule items to reflect 'live' capacity constraints such as the current load at a given work centre). I'll provide a brief description of our current practice and raise questions alongside that. If there's any misuse, do say so.

Overview:

A 'Required Date' is specified when demand is created, used to say when project 'X' is desired. Does this input need to be constrained by a lead time, whether plausible or not? For instance, can you specify the Required Date for X as 1/1/15? I'm not asking whether the system has an internal lock denying the user the ability to state that value. Instead, would the Need Dates found in the supply elements (production orders) of X be in the past as a result? As, perhaps, the lead time calculation begins in the past with reference to the Required Date stated for the top-level. If so, is the prospect of Need Dates falling into the past a problem? If Need Dates for the works orders/pieces do not occur in the past during this stage of a project's cycle, what causes the Need Dates to be assigned too strictly resulting in an order not finishing before? Is it the basic (pre CBS) lead time associated with X? The underlying assumption in these questions is a causal relationship between Required Date and Need for the top and subsequent levels. Is that correct?

The questions above are skewed towards suggesting the Need Dates for all levels of a project need to be in the future and achievable. I say this because when they are in the past this causes a 'change in priority rule'. For example, if the Need Date for order O is in the past , yet remains in process, the 'Due Date' for that order (equivalent to when its requires by the next level i.e. parent part) is redefined by when the last OP of that order is scheduled to finish + transport time to be booked into stock. This is wholly divorced from the Need Date instead about actual capacity (since APB figures here).

In any case, MRP's main offsetting process raises all the supply orders for a project with their dates (including Need). Let us describe this as a 'rough cut' plan. With these orders sat at 'Planned' status I load them into APB and proceed to use that to bring any orders forwards if there's available capacity (more details on the APB parameters can be provided).

My scheduling problems are fairly simple despite the convoluted line of questioning above. Using the tools on hand, how can I ensure a product has its levels aligned correctly and then scheduled to finish asap. And then multiply this in the context of an MPS that accepts new project at intervals.

Any help would be incredible. Especially insight to how Need Dates behave (and their prescribed used in IFS).

Many Thanks,

Jay

@JoherM   I had this explanation recorded that I provided to one of our Operations Managers, it is not a direct answer to all of your questions, but maybe you will find some of the information useful.  I’ve removed all of the personal information, but you can see it was a conversation.  I’ve put the initial question at the start, then the response after for ease of reading.

Best Regards,

Shawn

@JoherM 

I think I get the question. Let me re-iterate.  Lets say, D0 is the current date and D10 is the activity early finish date. Lets say there is a 12 level structure where each level ( part) takes one day. So if you run pMRP the last 2 parts will be planned to manufacture in the past which is not practical and that the planner has to intervene. 

Help from (p)MRP is , it will give you, “ demand/ supply past due “ action message.  Planner can start from there to attend to the situation.

(p)MRP can run with CRP support ( means  real routing run factors will be considered ). this will be more accurate and the results will be quite similar to what CBS/APB processing time calculation will result.

If user takes action on action message , that will result in mismatch between project ( active) dates and there will be exceptions in the project , activity level where planner has to take actions to solve them. 

If user releases (p)MRP created requisitions Shop orders will be created and the dates may not be exact with requisition dates ( due to various reasons ).  to make things balance again, need to execute (p) MRP again .  Then things willl fall in to place again.

Then if user wants to finite schedule shop orders using APB/CBS then again those schedule changes will trigger, project exceptions. planner has to intervene. Then to make things balance again  ( material perspective ) (p) MRP has to be executed which will result new action messages where user has to take actions, 

So it is a cycle of actions that the user has to have a acceptable schedule. Run (p)MRP, attend to action messages, resolve project exceptions, Run (p)MRP again. Then release requisitions ,  use APBCBS to schedule shop orders, attend to project exceptions arises due to that. then again run (p)MRP to make sure things are in desired time slots. 

This is how I would think that you can achieve the best schedule because here 3 planning engines are invloved. MRP, CBSAPB and project. The work routine of the planner is very much situational in my opinion. 

Hope this helps

Saman

Thanks guys, 

 

I agree that planning can be quite situational. I didn’t help that at the time of writing the post, I was fairly inexperienced  with IFS. I have learned a lot since then and can spot which concerns I raised are false starts.

 

In any case, you’ve provided a lot of ideas to explore Saman, thanks again.

 

Jay

Hi Anyone any idea on how to adjust need date that it is in inventory x days before demand requirement, we have currently picking days set at 3 days but the Shop Order due date date is only completing the day before the next shop order requires this component.  Therefore no time given to reserve, pick and issue parts in advance ?

If the demand is coming from a Customer Order, you can define a picking time and a transport time on the Customer Order / Delivery Information tab. These will drive the Planned Due Date (which is the date that MRP will plan for the part to be onhand) back a bit to give you the time needed to pick and delivery to meet the Wanted Delivery Date.

And in relation to the calculation of Need Date above, as you spotted, the MLT is not used by MRP,  it will calculate the shop order duration using (fixed time) + (variable time x Lot Size), then work backwards from the Need Date to place the Start Date. And make sure you have Machine Factor on ALL your routing operations (esp. any outside ops) else the duration will be incorrect.

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