You want to firm several planned production orders with same start date. A certain work center (e.g. Lathe-1) is used in every route. The firmed production orders got scheduled with different start dates.

Verify if the capacity is overloaded. If yes, job scheduling tries to schedule back and forth and back and forth until loop limit is reached. The error message "Attempts are made to schedule production before today's date or before materials are available." indicates not only material might be the cause, it indicates potential capacity overload, too. If material is not the cause, job scheduling cannot find a time slot with enough free capacity and end up with last attempt of forward scheduling and overloaded resources.

This is often caused by wrong or incomplete setup of work centers and work center groups. Assumed there are five identic lathes at shop floor, then create a work center group G-Lathe and add Lathe-1, Lathe-2, … Lathe-5.

 

The setup of group and single work centers should be identic, especially the calendar.

 

 

Then replace single work centers (Lathe-1) at all route operations with work center group (G-Lathe). The available capacity for the group is 5 times higher in our example than capacity of the single work centers. Assumed the calendar is defined with 8 hours per day, the group availability is 40 hours.

Depending of scheduling setup – operation or job scheduling – capacity reservations will be made on the group (operation scheduling) without reducing single work centers capacity or if job scheduling on single work centers and cumulated to group. Performance is better, if operation scheduling is used, of course.

In AX2012 there is improvement with capabilities. Details are in this blog: http://blogs.msdn.com/b/axsupport/archive/2012/09/20/scheduling-based-on-resource-capabilities-in-microsoft-dynamics-ax-2012.aspx.