In a modern foundry, cores are made by one or many of the same methods that are used for sand moulds. Plus, screw feed machines and core blowers are employed. This blog will cover the different core-making methods in a foundry.
Core blowers force sand into the core box with compressed air at about 100lb/in 2. Core blowers are applicable for making several types of cores: small-and-medium size cores. The cores made are highly uniform, and higher productivity can be attained by this process.
Screw feed machines:
Screw feed machines are useful to extrude plain cores, generally cylindrical. The core sand is pushed via a die onto a core plate. In foundries, the application of these machines is narrowed down to the production of stock cores: the long, extruded cylinder made by the screw feed machine is backed and then suitably cut into the required lengths.
Core driers are similar to cake pans—the shape of a core is supported whilst it is in the core oven baking. These are generally aluminium boxes or light skeleton iron, the internal shape of which is closely consistent with the core’s cope portion. Cores that will fall apart or have parts broken off are placed on a flat plate that passes through the core drier’s oven. This process is followed by placing the core which will be covered separately in another blog.