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FAQ - When should you use backflushing and when should you definitely not
when using MRPII and ERP systems?

Backflushing defined - The principle of backflushing is that whenever one part is made, the stock of the components on the part's bill of material can be reduced by the quantity on the bill of material. If, for instance, the stock of car batteries is held beside the car assembly line, the stock of car batteries can be reduced by one every time a car is made (typically the component stock is reduced when the completed work order is booked into stock).

For backflushing

  1. Relatively simple and easy
  2. Costs are allocated accurately to work orders for bulk issue items

Against backflushing

  1. Bill of material accuracy must be maintained at 100% including scrap factors
  2. Any changes to bills of material must be timed to match the backflush of the changed process
  3. Stock checking is more difficult as computer record must be checked with stock on the shelf plus all materials and ingredients that have been issued or used but not yet backflushed
  4. All scrap and re-work must be reported as soon as it happens
  5. Every single jobs requiring any stocked materials must have a work order opened and backflushed
  6. It is not possible to check material availability on the system prior to release of a work order as the system does not create allocations for backflush material (so only 1 work order can be checked at a time) and the computer stock record does not reflect what is available.

The alternative to backflushing is to issue material from stores either on a pick list based on a works order system or by discrete or bulk issues accompanied by a requisition. Every movement of stock from a stores area should be matched by a transaction on the system.

Jargon Warning - If you are not familiar with any of the terms used above, you can look them up in the free Jargon Buster on this site or, for more details, purchase the book "Business Excellence". Business Excellence is available in e-book format in addition to the paperback and is a component of the ERP Class "A" toolkit which you can also purchase and download from this site. Click here for more details.