Can assembly (BOM) be setup so MRP ignores components?

We have assemblies, typically circuit boards, which we (nearly) always outsource for manufacturing. The BOMs for these assemblies are fully populated in our system, but most of the components will be supplied by the outsource vendor. However, there are low-supply components that we keep in inventory, due to lead-times or lack of alternates. These components are consigned to the outsource vendor when we need the circuit boards made. These low-supply components can be tracked in MRP with reorder point settings.

There is an advantage to having the BOMs in Cetec, but when we run MRP, or add recursive bom forecasts, all the subcomponents of the circuit boards show up in MRP. Is there a way we can set the circuit board assembly as a ‘buy’ item, so MRP will ignore the subcomponents?

Please note our circuit boards themselves are subcomponents of other assemblies, and may be 2-3 BOM layers from the top-level component for which we setup the forecasting.

Thank you!

Hi @JesseH

You mentioned you’re using the “recursive BOM” forecast function in Cetec ERP, that’s a helpful detail and will inform some of our advice below.

For the sake of example, let’s take a multi-level BOM with top level part number “TOP123”, pcba subassembly “SUBPCBA”, and subcomponent “CAP-000”.

The first thing to note is that if your SUBPCBA is actually in stock and available, then it will not show up in MRP-BUILD as needed demand. Therefore, it won’t be put on a work order, and therefore, demand will not ultimately show in MRP to buy the CAP-000.

However, if you have a recursive BOM forecast activce in the system, it will drill down to register demand at every level, on both the SUBPCBA and on the CAP-000 component. But, it will ONLY register that demand to MRP if you are running MRP with the “include forecasts” setting turned on.

Zooming out, the rough process here should be to first run MRP (with “include forecasts” turned ON) and create work orders to satisfy the demand for Top-Level Parts that are being demanded by both active sales orders and the next month (or x months) forecast-specific demand… only for the top-level(s) of the BOM. Use a filter on MRP so that the lower levels (e.g. the CAP-000 subcomponents) aren’t displayed in MRP.

The above process running MRP with “include forecasts” on (and entering work orders only against those top-levels) is usually done once a month.

Then, on a normal day-to-day basis, a buyer (or builder of deeper-level subassemblies) can run MRP with forecasts NOT included to see the ultimate net demand against those lower/deeper levels of the BOM (e.g. the CAP-000).

Remember that the trick to not seeing the lower-level subcomponents on MRP is using a proper filter on the MRP itself to filter those out from view.

We hope this helps, thank you for your question!

Thanks for the quick response and apologies for my very late one. We have been working through as best we can, but are still working on our understanding of MRP. To check my understanding of your recommendations:

  1. Once per month, check the “Include Forecasts In Next Allocation Run?” checkbox and let allocation run with forecasts included.
  2. Run MRP, but use filtering to focus on Top-Level Parts only (for us this would be PRD ‘product’ parts).
  3. Use MRP to create work orders for the Top-Level Parts.
  4. Uncheck the “Include Forecasts In Next Allocation Run?”, and let allocation run without forecasts included.
  5. On a daily/weekly basis, the buyer/builder will run MRP and use it to create orders. This would be iterative: run MRP, create POs/WOs, repeat. This will naturally drive down the BOMs top-down: creating planned ‘supply’ for ordered (po/wo) parts and generating ‘demand’ for parts on the order pick lists. These will show in the waterfalls in MRP.

If I am understanding correctly, using the above process we don’t need to load our forecasts using the ‘Recursive’ function, as it just complicates step 1 by requiring additional filtering. We have had the ‘include forecasts’ option on perpetually the last several weeks - but it makes the MRP list long and and harder to focus on immediate priorities.

Does the above seem correct?

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