MPS planners use what is referred to as time fences? What are they, and why are they used? (Points : 20)
Ans: The inputs to MRP frequently change. This occurs in one of two ways: by recomputing the requirement and schedule periodically, often weekly, or via a “net change” calculation. Net change in an MRP system means the MRP system creates new requirements in response to trans-actions. However, many firms find they do not want to respond to minor scheduling or quantity changes even if they are aware of them. These frequent changes generate what is called system nervousness and can create havoc in purchasing and production departments if implemented. Time fences is particularly helpful when trying to reduce MRP system nervousness. Time fences allow a segment of the master schedule to be designated as “not to be rescheduled.” This segment of the master schedule is therefore not changed during the periodic regeneration of schedules.