The MRP action window is based on replenish time
The MRP “action window” refers to each item’s planning period, which is used to assess net demand for job and PO generation. Ideally, the planning period is equal to the item’s replenish time. For M items, replenish time is primarily comprised of the item’s Lead Days plus Job Days allocations. For P items, replenish time is primarily comprised of the item’s Lead Days allocation.
Demand outside the action window needs no current action
Any demand that exists outside an item’s action window is not fully complete and needs no current action. This is because ample time remains to initiate stock replenishment at a later time when that demand firms up and eventually falls into the action window.
The action window limits the schedule to current requirements
The MRP action window limits the master schedule to requirements that need current action. All dates in the schedule, with the exception of blanket sales orders, are short term in nature.
The short term nature of the system targets makes for realistic dates
The short term nature of the system targets makes for dates that are realistic upon their generation without any need for manual adjustment.
Avoid adding extra days to P Item Lead Days or M Item Job Days
The scheduling system works most efficiently when the MRP “action window’ is equal to each item’s replenish time. Avoid adding extra days or padding to your P Item Lead Days or M Item Job Days. Fictional values in your lead days and job days will severely impact your system target dates, material allocations and your inventory stocking levels. If your objective is to enlarge your item's planning period action window during MRP generation, you can go to the MRP Setup - MRP Defaults and add extra days to your MRP replenishment time.
Replenishment time also affects how much stock you carry
The dynamically calculated reorder point in the Demand Driven order policy uses the Monthly Potential Demand value and converts it to a daily rate and multiplies that by the replenishment time. Making sure you have reasonably accurate replenishment times will lead to a more efficient inventory.
