MRP question regarding historical dates

Hello there, got an interesting issue.

Normally, Purchasing Suggestions occur as a part of MRP runs. When we run MRP, we do not allow historical dates, as we do not want planned jobs to start in the past.

However, we would like to have our purchasing suggestions use historical dates.

If, immediately after running MRP with historical dates turned off, we then reran Generate Purchasing Suggestions with historical dates turned ON, would we get what we are looking for? What we want is the system to drive accurate receipt dates regardless of lead time. We are in a business where our demand can increase inside of our supplier’s lead time, and we do not want to use dates that are limited by lead times for buying. There are many situations where although the supplier might be challenged to meet an under-lead time increase, in many cases we can work towards that goal (Our lead times are long, it is not uncommon to have a one year lead time on our materials).

Since the two functions (MRP and suggestions) run together, I was curious if anyone else has encountered this, and attempted the fix I am thinking about.

If you run the Purch Sugs with the allowance of historical dates, you should be able to get past order date PO’s. The PO’s would sync to the Required by date of the material in the MRP run and your lead times, so I don’t think much will

Charlie Smith

CRS Consulting Svcs

(860) 919-1708

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I am conducting a trial in our test environment now. The planned jobs were fine, they were scheduled to start on time. The issue is that the material need date is based upon lead time - regardless of need date.

I’m thinking backdating the suggestions will take care of this.

We use historical dates in PO Suggestions - it changes our “Order By” date to the past. The buyers can then sort by order by date and find all the parts they need to buy and expedite ASAP since we are already less than lead time.


This is exactly what I was looking for, and was able to validate in our test system yesterday.

We do not want the system to use historical dates for unfirm jobs, but we want historical dates on the suggestions. The selection box on the MRP launch screen applies to both unfirm jobs AND the purchasing suggestions imbedded in the MRP run.

By regenerating purchasing suggestions immediately after MRP, we are able to generate purchasing suggestions with historical dates. This is a significant improvement for us.

I am grateful for the folks who responded to this thread. I shall update here if we have any more findings related to this issue.

I believe the settings you need is to not Allow Scheduling Before Today under Company Configuration. (It’s checked in mine, I just included it so it would be easier to find.) If you have that set to false, then you can allow historical dates when running MRP and it won’t schedule any of the jobs in the past. Just test to make sure, but I am almost positive this will give you the results you want.

I have tested that, and it does not work as expected. We do not allow scheduling before today, but if this flag is cleared at the time of MRP launch, we do get jobs scheduled before today.

Not an ideal situation in our environment. We are going to use our workaround only when we get customer demand that is under lead time, partly to prioritize the suggestions, and partly to give us the date we originally wanted the material to meet revised schedule.