A part record specifies some material that is required to perform the operation. That material, may be bought (a ‘raw’ material) or made (a sub-assembly) or both. The material required and how much of it can be specified. Usually, the quantity specifies how much material is required to make ‘one’ of something. The planning system then scales that up as necessary to meet any particular demand. The stock allocation algorithm is aware of dimensions and min/max size constraints, and various other factors and takes these into account when calculating yields.

The PART record specifies ‘what’ you want and the planning system calculates ‘how’.