MRP Scheduling Question

We just implemented Epicor and have a basic question. When we run MRP it is placing the MRP suggestion jobs into the schedule ahead of our released jobs, We sometimes have to pull jobs up to satisfy an important customer and the system won’t let us schedule those jobs ahead of the MRP suggestsion jobs. Is there something were are missing in our setup that will help us with this?

do you guys use global scheduling?

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It sounds like you might be doing finite scheduling. With finite turned on, you are not allowed to over-fill a finite resource… OR if you have a constrained material, you will have the same problem.
When you reschedule a job, there are check boxes to override these. Turn ON the override material constraints, and turn off the Finite Capacity.


We are not using global scheduling.

We are using finite scheduling and we need to, those machines are definitely finite.

You could try Locking the Job Schedule, this should keep the important customer Jobs in place and suggested Jobs would be scheduled around it.

Set your required dates and check the ‘Locked’ check box on Job Entry.

Disclaimer, I do not use Finite Scheduling and have not tested this.

well, if you use finite scheduling, then the system will not let you schedule something into a timeframe when there is already something in that position taking up the finite space in time.
the only way to “Insert” something into the schedule is to change the global rescheduling order, and then globally reschedule everything, OR, find what is already scheduled for that timeframe, and remove it from the schedule, so that your new item will fit.
You can think of “finite scheduling” as individual time shelves that only hold one part per shelf. If the shelf is full, it wont let you put another item there. you have to empty the shelf first. When you do Global Rescheduling, it empties all the shelves, and then starts refilling those shelves in a particular sequence. You can set that sequence of which order gets first priority to fill each time shelf.


Yep, I get how finite scheduling is supposed to work, however we are seeing jobs push out and there isn’t anything else scheduled in the resource. I tell the system I need the job by 4/8 and schedule it and it will start it 4/15 and won’t let me pull it in any sooner. We have tried to forward schedule a particular job and it just won’t budge.

do you have a constrained material?

FYI. Buy direct materials on a job are considered constrained materials. Those materials lead times will dictate the related ops start date.

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