Best Practices and Critical Checkpoints for Running MRP for IFS10

1) Inventory Part > Planning tab: must‑check fields

For each planned part at the site, on Inventory Part → Planning Data / Planning:

1. Planning Method / MRP Order Code

   • Choose the correct Planning Method (A, B, etc.) and MRP Order Code (manufactured vs purchased).

   • For Method B (Order Point), ensure Order Point and Lot Size are filled correctly.​

2. Lead Times

   • Purchasing: Purch Lead Time, Safety Lead Time where relevant.

   • Manufacturing: Manufacturing Lead Time, and routing times must be realistic.

   • Wrong lead times are one of the biggest causes of bad MRP dates.​

3. Lot sizing & order multiples

   • Fields like Lot Size, Minimum Order Qty, Order Multiple.

   • Ensure they reflect reality; otherwise MRP will propose odd quantities.​

4. Safety Stock / Demand time fence

   • Safety Stock where truly needed (and not higher than order point in method B).

   • If using Time Fences (e.g., Stop MRP inside X days), set them deliberately, not left at strange defaults.​

5. Default Supply Type / Source

   • Confirm if the part should be Manufactured, Purchased, or External source.

   • Avoid mismatches (e.g., manufactured part with no structure or routing).​

2) Calendars: manufacturing vs distribution

1. Understand which calendar drives MRP

   • MRP works internally with the Manufacturing Calendar; if a date is a working day in Distribution but not in Manufacturing, MRP will move the demand or supply to the nearest manufacturing working day.​

2. Checks to do

   • For the MRP site, verify:

     • Manufacturing Calendar: working days, holidays, shifts are correct.

     • Distribution/Delivery Calendar: aligned with customer delivery expectations but aware that MRP will still use the manufacturing one internally.​

3. Issues from incorrect setup

   • Demand dates being shifted one day earlier/later versus CO/CPO dates.

   • MRP suggesting unrealistic start or due dates (e.g., production in non‑working periods).

3) Low Level Codes (structure levels)

1. Need to calculate low‑level codes?

   • Yes, especially when starting MRP or after significant BOM changes.

   • Low‑level codes ensure MRP plans lower‑level components in the correct sequence.​

2. How to handle it

   • Make sure the “Calculate Structure Levels / Low Level Codes” background job (name may vary) is run at least once before the first MRP.

   • After big BOM changes, schedule it periodically or include in your MRP pre‑jobs.​

If low‑level codes are missing or outdated, MRP may plan components before parents or fail to generate correct proposals at deeper levels.

4) Common pitfalls (and how to avoid them)

1. Bad or missing master data

   • Parts planned by MRP without:

     • Valid structure/routing for manufactured items.

     • Valid supplier and lead time for purchased items.

   • Fix: run simple validation lists (e.g., “MRP Planned Parts without Supplier/Structure”) before go‑live.​

2. Incorrect or inconsistent calendars

   • Demand dates not matching MRP dates because manufacturing calendar excludes days that distribution/calendar uses.

   • Fix: harmonize calendars, or at least know that MRP always uses the manufacturing calendar for its calculations.​

3. Unrealistic lead times & lot sizes

   • 0 or minimal lead times, or huge lot sizes, causing nervous or impractical plans.

   • Fix: review lead times for top runners first; adjust based on real history.​

4. Ignoring existing supply/demand cleanliness

   • Old, obsolete COs, POs, or shop orders distort the MRP snapshot.

   • Fix: clean up or close outdated orders before the first formal run.​

5) Suggested step‑by‑step procedure for first MRP run

1. Master data review (site‑specific)

   • For all MRP‑planned parts: check Planning Method, MRP Order Code, Lead Times, Lot Sizes, Safety Stock, Default Supply Type.​

2. Calendar validation

   • Confirm Manufacturing calendar for the MRP site is correct and aligns with real working days; review Distribution calendar understanding MRP uses manufacturing for its calculations.​

3. Calculate low‑level codes

   • Run the structure level / low‑level code background job once.​

4. Clean existing orders

   • Close or correct obsolete CO, PO, SO, and reservations that should not influence MRP.​

5. Run a test MRP in a non‑production or test scenario if possible

   • Analyse MRP Part Information (Top‑Down, Bottom‑Up) for a few representative parts and compare proposals with expected logic.​

6. Adjust parameters as needed

   • Tune safety stock, lead times, lot sizes and calendars based on the test results.

Some additional comments:

• MRP does not process parts with planning methods B (Order Point Planning), C (Replenishment Level), M (Manufacturing Cell Part) or N (Next Level Demand).
• Lot Size pertains to planning methods B & C, so no effect on MRP.
• Need to consider Min/Max/Multiple Lot Size attributes, along with Scrap Factor (%).
• The calculation of low-level codes is a phase in the MRP calculation. There is no standard method to calculate this outside of MRP.