(Purchasing) Lead Time MRP bug or feature for Manufactured Parts?

I stumbled across an old part in our system that was marked as Manufactured, Process MRP, and the Purchasing Lead Time set to 45. The warehouse inventory settings had not been cleared so MRP was creating a job to get inventory above the ROP. We did not have any other demand in the system so the Job suggestion was just for stock.

The interesting thing I found, was that MRP would forward-schedule starting 45 production calendar days in the future. I changed the lead to 90 and ran it again in our Test Environments(10.2.600.9 and 2022.2.10) and confirmed that MRP will forward-schedule starting 90 production calendar days in the future. And then testing again by clearing the Lead Time and running MRP again, the Job was scheduled to start immediately just like other stock-only suggestions.

If firm demand, such as a Sales Order is created, MRP will plan for that due date and ignore the lead time number.

I’m curious if anyone has seen the same functionality and if anyone is utilizing or would utilize this or is this just a bug in MRP? I could not find any MRP documentation that a Manufactured part would use this field in the MRP planning process.

I know in some cases when we get into the busy season, we don’t always want to work on stock-only jobs for certain parts. I’m wondering if we should use this to help push out Job dates for stock-only jobs(so that they are not always due immediately) and pull them in as the schedule requires or when we can fit them in.

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Sorry for bumping this ( Necroposting…) . I have just run across this in our system and was looking in the posts for any reference to this and found this post.

Odd that no comments on this…


I don’t have an answer, but the part used to be Purchased and was changed to Manufactured?

Were the steps in Help followed (I forget if the steps are from Mfg to Pur, Pur to Mfg, or both)?

Are the Part level and Part Site level the same (both Purchased)?

Hi John,

Part was always Mfg
Question 2-N/A
Yes , same in Part and Site.


Adjusting for lead time only if there is no firm demand seems like odd behavior on the surface. Also, dropping below minimum without demand sounds like a rare scenario, but not impossible. The scenarios that come to mind right away (qty adjustment, nonconformance) would drop the part below minimum immediately so accounting for lead time in those situations seems odd too.

Also noteworthy, that lead time field is used in the ‘Min/Max/Safety Mass Update’ process as well. Not sure how/if that is intended to work with MRP. It is used in conjunction with these fields to calculate values for min/max/safety accordingly:


On the surface yes. Example, we have a slow moving item Min 2 max 5. 2 on hand. Sales Order takes 1 ( is shipped) . Qty now 1. EPR runs that night. Creates u job for 4 ( we have reorder to max set, working on moving people away from that… ) Lead time for Mfg part was set to 50 ( at 1 time we thought that was a good idea to calc Min max values on the side) . Component Purchase part P1 that is needed for said Mfg part we only have 1 on hand, PO suggestion puts part due at today + 50 days. Lead time for P1 is 20 days.

Thats where the problem lies…


Interesting. Do you have a manufacturing lead time populated, either calculated or manually entered?

I’m wondering if there is a hierarchy of where lead time for manufacturing comes from. I would think that the Manufacturing Lead Time would be first, if there is not one entered then it takes the Purchasing Lead Time?

Does this part have an approved Revision and Method?

Manufacturing Lead time No
Approved Rev Yes.

If a hierarchy, Why 0 on time Phase ?

Try entering a Manufacturing Lead Time on the part and see what happens.

There is a setting to include purchasing lead time in the manufacturing lead time calculation in Site Maintenance → Planning


Testing in Pilot right now, Will post findings…

Unfortunately that didn’t work, U job created 7/4/2024, expecting today…

Will try setting Mfg Lead time to 1 day … stay tuned…

Back to square 1, U job still way out there ( 7/4/2024)

That setting is for calculating the Mfg Lead Time. That determines what the system considers when you run the Calculation Process.

I was referencing the Manual Mfg Lead Time you can enter on the Part. I would include screen shots, but that is not in 8.

Is this what you were referencing ?

Yes! Now when you run MRP, what is the lead time on your part?

Still 7/4/2024

When I changed Mfg Cumulative time to 42 and Purchasing lead time to 0 , Ujob created now

That stinks. I was hoping.

@timshuwy , do you have any insight to the issue? To sum it up, why does MRP use the Purchasing Lead Time on manufactured parts?