In MFCA, finished products and waste are respectively termed positive and negative products. In a processing-type production system, waste is generated in various steps of the production process. In particular, in the process of stocking and production, waste is substantially produced because materials and intermediate products that are overstocked as inventory may deteriorate in quality or be scrapped. Additionally, while materials or intermediate products are processed,
residues or shavings may be generated. All of the wastes mentioned above are called “negative products”
and lead to environmental burden. In MFCA, the idle processing, unnecessary energy and auxiliary material
consumption caused during the waste generation are also called “negative products” and treated as
environmental costs