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 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 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 descrete or bulk issues accompanies by a requisition. Every movement of stock from a stores area should be matched by a transaction on the system. The best education course to help you both decide on backflushing and all the other important factors when setting up a planning and control system is theBusiness Excellence Fundamentals course.

Phil Robinson - www.bpic.co.uk
BPIC - your manufacturing planning resource