Scheduling Locked Jobs

I’ve been playing around with manually scheduling and and locking scheduling priority and I hit a wall.

  1. Build to stock
  2. SO for 20 pieces
  3. Firmed job of 20 pushed out and locked.
  4. If the push out is greater than the manufacturing lead time Epicor MRP generates a PWO for and additional 20 pieces.
  5. I now have a PWO that is sooner than the firm job, driving material for an additional 20 pieces, exceeding demand.

Is there a way to prevent this from happening?

You need to change the demand date on the Sales Order, MRP is simply trying to match up demand qty and dates, so your Job will not satisfy that demand so it creates another.


Thanks for the tip, but leads to another issue. We load the customers request date in the need date, and we cannot move that. I was hoping to use the SO Shortage report to identify when we are not meeting customers need date.

Was hoping there was some way to set not to exceed total demand.

which lock are you using? date or qty lock?

This is where I have preached that people need to change their thoughts… There are two dates in the Order Release… need by, and ship by.
the Need by is what the customer wanted
The ship by is your “current” promise date. It is what drives everything… MRP will ALWAYS drive to this date. If your jobs do not meet this date, then MRP will try everything in its power to make it happen… if you lock the supply date/quantity, MRP will then tell you to make more. it is the way Epicor is designed.

My additional suggestion (and ongoing enhancement request) is to add a THIRD date to the sales order called “Original Promise Date”. This would be the date that you initially promised. It is what you would measure performance against. It “never” changes, unless the customer requests the change, OR unless you ask the customer if you can change it, and they agree to the change.

The SHIP BY date should be flexible, and should be adjusted whenever the supply cannot meet the demand.
(ok… i will step off my soapbox).


Tim - your point is critical. Currently experiencing this due to a migration from V8 to E10, and we do not populate the dates properly.

We have to switch the dates on all of our open PO’s to get MRP to work to the correct information.


Tim, your reply is perfect. Almost every issue we see that has to do with “bad information” in the MRP runs is due to a mismatch between the demand date and
the supply date. Using the Ship By Date to remedy this is the best and really only way to properly align the two.


If you truly want to measure customer satisfaction then you will have to account for transit time also. Otherwise the customer PO and your Ship By date will not line up. We factor in the transit time for the customer in determining our due date.

But to the OP’s points, moving the Ship By date so that MRP doesn’t create unnecessary orders does work however the materials organization and production will lose all urgency in obtaining the part or building the product any faster. Ideally a material constraint should reach a level of certainty where purchasing has the delivery date nailed down. If this is the case, the job *should become an ‘island’ in production with everything being scheduled around it (by locking the schedule). The job *should be started with the part being issued to the job just in time to the operation which requires it.

How about make direct? Would it solve the issue if the job were locked to the release? Or would their dates be in sync thereby continuing the urgency obfuscation?

Tim, totally agree. In old days days had to use vb fields. But this should be a basic part of the system. Pls let us know the enhancement request.


Mark, if the job is make direct, then it would NOT create a separate job for missing the schedule as long as there is a job linked… it WILL show in the planners workbench if the dates don’t match.
but, when it is make to stock, the system simply doesn’t know why there is a delay… it doesn’t know why you locked the date/qty… but it does know that you have a demand on a date.
There is a “time-fence” in the part settings that will disallow any planned jobs prior to the time-fence… but that causes a whole plethora of additional problems. (hahaha… I got to use the word “Plethora” in a sentence again).

Thanks Tim. I appreciate the comment. I think I’m starting to make some headway with leadership to move in this direction. Once issue we have, is if we move the ship date out, what tools do we use to attempt to identify constraints (material) and attempt to get back to or closer to the need date?