PO Suggestions and Lead Time

I’m curious if I’m missing something with PO suggestions.

I have an order for a purchased part that has a ship by date of 12/20. We currently run MRP with a Dynamic cutoff date of End of Month +3 months (today is 8/23) end of month is 8/31, + 3 months is 11/30. Currently the part does not have a lead time on it so I wouldn’t expect it to show up in the po suggestions. I then added a lead time (PartPlant.LeadTime) of 30 days to the part and re-ran generate suggestions and I still didn’t get a suggestion. I would have expected it to show up with the additional lead time.

I re-ran generate suggestions with End of Month +4 months (which bring the cutoff to the end of December) and the suggestions show up.

Based on the help I would expect the the lead time to be factored into the generate suggestions and am curious if there is something I am missing that would cause this behavior?

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Lead Time for purchased parts can get confusing fast. Do you have a Supplier Price List for the part or something assigned to the Part Class? If I am remembering correctly, the place you added the lead time is one of the last places the system looks in the hierarchy and may have never reached that level.

So… here’s more information. The part does not have a supplier on the part plant so I didn’t think to check there. I just did and the supplier we usually use does have a supplier price list with a lead time, I changed it to 30 days (from 15) and re-ran generate suggestions but didn’t get anything. I then checked the Part Class default lead time and it was set to 0. I changed it to 30 and re-ran generate suggestions but still didn’t get a suggestion.

Then to make sure I’m not losing it I changed the generate suggestions to End of Month +4 to make sure I wasn’t losing it and it did generate the suggestions. So… I guess maybe I am losing it, it’s hard to tell at this point.

Couple of things to look at. What is the status of the job the part is tied to (Engineered, Released, etc.) and then what is the Site setting for when Dates are assigned to purchased parts.

The part is directly on an order so there isn’t a job for it.

The site settings we have a standard 5 day calendar which I would believe would just remove the weekends from the ‘lead time’ . I don’t see anything else in the site parameters that looks like it impacts the purchasing suggestions?

I’ve never worked with Buy to Order. Are you capturing a detailed log? I would run PO Suggestions and check the log to see if it is even in the log.

Hi Max,

What does Time Phase show for this part? Do you have an on hand quantity? Do you see the demand from the Sales Order?


Hey Beth!

There are 0 on hands for the part and the part is marked as buy direct, and I see the demand for the part in time phase.


Type is setup as Purchased on both the Detail tab and the Sites > Detail tab, correct? On the Sites tab, you have a lead time setup and a supplier? The Generate PO Suggestions checkbox is checked and the Buy To Order (Buy To Order is on the main Detail tab too)?

Yep, purchased on site and detail tab.

Lead time and supplier are setup. PO suggestions is checked.

The part is not buy to order but was overwritten on the order line, would that impact the ability to get suggestions? I get suggestions when I move the date out an extra month (End of Month +4).

Nope, Buy To Order shouldn’t impact suggestions. I’m taking it that this is a one-time buy for a customer.

If you are getting PO suggestions when moving the date out, then it’s something in the calculation.

So your assumption was that MRP will do the analysis and then only show you suggestions within your cutoff date… but it actually works differently.
The system will only analyze the DEMANDS that are within the date… so since your date of 12/20 is outside the 3 month window, it will not analyze it. EVEN IF you had a 6 month lead time (meaning you are late) it will not look because it only sees the DEMAND date.
That said, you need to set the cutoff date to be at least as long as your longest lead time for any product. If your longest lead time is only 1 month, then you can do the cutoff going out two months, and you will be safe. but if your longest lead time is 1 year, maybe you should just drop the cutoff all together.


When running PO suggestions, are you running it as Net Change or Regenerative? If you are running t for only this one part, then it’s running as Net Change.

Have you tried running it and leaving Dynamic unchecked?

Evidence shows you are correct @timshuwy (not that I ever doubted it :wink:), but it just feels wrong that it wouldn’t take into account the lead time.

I understand the DESIRE to have it work differently, but the leadtime can get really complicated with all the variables. Note that Jobs and Purchasing, the leadtime can change based on mulitple factors. If you have PO Scheduling which chooses different suppliers based on the day of week, your leadtimes can be different for each PO. For JOBS if you use Finite scheduling, you can have a job that COULD be made in 1 week, but due to capacity, it would take 10 weeks. We would not know that until after we try to schedule.
All that said, it does work as defined, and it has a “logical” break in which items will be examined. You can properly predict if an item is going to be analyzed becuase the rule is very clear. The workaround is to extend your date bigger than any leadtime you have.