Why is a BOM demand explosion not available?
DBA is a demand-driven, just in time manufacturing system that uses Time to Shipment MRP for item planning and job and PO generation. DBA does not include a BOM demand explosion because it is counter-productive and incompatible with the system's demand-driven, just in time architecture.
Just in time manufacturing is item-based
Just in time manufacturing is item-based. This means that demand for each sell item, subassembly, and purchased item is independently assessed in each MRP session without regard to any particular sales orders, jobs, or product structures to which the item may belong.
You don’t make a product structure
With just in time manufacturing you rarely make an entire product structure like you see depicted in a multi-level BOM view. Subassemblies and purchased items in a product structure are often independently planned for stocking and many such items are used in multiple BOMs and often have interdependent demand from multiple jobs.
BOM demand explosion is a traditional planning method
BOM demand explosion is a traditional planning method whereby demand for a parent item is exploded down through all levels so that the entire product structure can be made with a set of linked jobs.
BOM explosions are counter-productive
BOM explosions isolate demand into separate product structures and force all subassemblies in the structure to be made to order. This planning method is counter-productive.
•BOM explosions fail to account for interdependent demand from multiple jobs and result in an excessive number of fragmented jobs with inefficient run sizes.
•BOM explosions force subassembly items to be made to order, even in cases where it would be more efficient to plan the item for stocking to reduce time to shipment.
Linking occurs naturally with item-based manufacturing
With item-based manufacturing, linking of a sorts occurs naturally when supply events happen to align with demand events. Unlike hard-linking, natural linking also flexibly allows one supply event to align with multiple demand events.
The Stock Status inquiry shows the destination of any item
It is not necessary to use hard-linking on job travelers to know the destination of a finished subassembly item. The Stock Status inquiry, which can be accessed within the Job Receipts and Job Schedule screens, indicates which jobs are pending for the item.
Do not attempt a simulated BOM explosion
Do not attempt to create your own BOM demand explosions and manual jobs to simulate your traditional planning method in DBA. This is completely incompatible with Time to Shipment MRP’s item-based architecture and interferes with time to shipment planning, item order policies, scheduling dates, and job release.
Time to Shipment MRP cannot be replaced with alternative planning methods
Time to Shipment MRP is the core element in DBA's demand-driven, just in time manufacturing architecture and can't be replaced with alternate planning methods.
Just in time manufacturing requires a standard Lead Days for procurement time against all P items, a standard Job Days for production time against all M items,, and a consistent To Order or Stocking order policy for lead time contribution against all items. Stocking order policy items require supply pipeline settings to replenish stock at demand-driven intervals. Demand-driven jobs and purchase orders are generated by MRP on a daily basis to assure that materials are on hand by job planned start dates.
This demand-driven, just in time architecture is not compatible with alternative planning methods. Use the item planning settings as designed and you will get good results, whether you make to order or to stock or have standard or customized products. On the other hand, if you bypass or co-opt item settings or bypass MRP generation with manual planning, you will get very poor results.
