Cast iron plate blank casting:  The process of casting blank by mold design and casting. The mold includes the product appearance and the pouring system. The gating and riser system include the straight runner    runner  inner runner  and riser. The gating and riser system will be remove during the sand cleaning process and will be regard as the rubbish. The weight of the cast steel casting system usually is 70%-150% of the product blank weight. Gray cast iron: 20%-35%.  Ductile iron: 20%-40%. Say producing the 100kgs cast steel need 170-250kgs liquid steel. (Cast steel with high temperature, shrinkage, the requirement of feeding is very high). Producing 100kgs gray cast iron need 120-135kgs liquid iron. The other 20-35kgs is the weight of the gating and riser system and will regard as the rubbish to melt down.
   Except those additional cost, there are also other reason to generate  the rubbish, for example: Shrinkage cavity, shrinkage porosity and porosity etc. The rate of the rubbish usually controlled 7%. Those are all the direct cost factor of the casting producing.
   Cast iron plate processing: parts drawing is the most important information. The product is processed according to the drawing. Drawings shall clearly show the name of the parts, tolerances, surface roughness, key dimensions, processing standards, inspection requirements, heat treatment conditions, etc.. According to the technical requirements, the processing method can be determined. Product processing also has cost loss, such as: processing waste products and due to the processing of the waste caused by exposure to casting.