Sand Casting Costing | Analysis

Sand Casting Process Costing In Foundry

Sand Casting Costing

For manufacturing casting in small sizes and quantities with lesser cost hand moulding is done but in larger foundry machines moulding is used to automate the process.
In hand, moulding sand moulds are made by hand which requires a higher labour cost and metal is poured in the mould by ladle. In hand moulding time required for mould is higher but the cost of producing sand mould is less as no machine is required.
In the machine moulding process initial cost of the machine is high and is justified only when there is a high volume of orders for producing casting. The time taken to produce sand casting using machine moulding is lower than the hand moulding process.
Machine moulding is more accurate than hand moulding and the process can be done using a semi-skilled operator while in hand moulding skilled operator is necessary.
Machine and equipment cost includes inspection and quality checkup cost that increases with modern equipment such as X-ray machines in the foundry.

Tools used in sand casting processes are patterns, core boxes, core prints, padding, chills and cores.
The cost of the pattern depends upon the size of the final casting, the material used and the allowance given on the pattern.
Wood as pattern material is cost-effective but comes with the drawback of change in dimensions when it absorbs moisture. Metal provides higher accuracy but is unsuitable for low-volume production as the cost is unjustified.
Padding and chills are used in the sand-casting process to provide directional solidification while casting is cooled. The more the difference in thickness in the final casting more there will be a need for padding and chills to have proper directional solidification.
More cavities and holes present in the casting will be the need for cores and core prints in the sand moulding process. This will overall increase the tooling cost for producing recess and cavities for casting with a higher number of cavities.
To improve the strength, toughness, and durability of cores, cores need to be cured.

Production cost will increase with the number of sand casting to be manufactured, the material used, the type of furnace used in the foundry, the efficiency of the furnace, heat loss during melting operation, the number of cores and core boxes used, type of material handling equipment used in the sand casting process, the energy required to melt, transport and cool material.
Production cost is directly proportional to the variables mentioned above.
Production costs will decrease when process parameters are taken care of and sand casting defects are reduced.
Material cost during the process is reduced when the final product is defect-free and passes through proper quality parameters to qualify as sound casting.
Production cost includes all costs associated with making core boxes, cores, core prints, mould making, cost of sand, melting metal, secondary manufacturing processes such as grinding, machining, passivation process, surface finishing operation, core curing, tumbling, sandblasting, sand curing, heat treatment, polishing, masking, anodizing, anti-rust coating, powder coating, sub assembling, zinc plating, spray-painting casting products, impregnating and coating.