Patterns and cores

Ingot Mould Fondry - Patterns and Cores

The most common methods of realization of foundry cores

In our ingot mould and cast iron fondery, the foundry cores and sand molds and resin are produced thanks to the production capacity of three mixers. Our company specializes in the production of patterns and core boxes in wood of different sizes.


When the product that you want to establish presents internal cavities or profiles not achievable with simple molding, they are used special souls. The soul is a form that reproduces the hollow parts of the object to be produced and you get compacting the earth in a container made of metal or wood, said core box, which shall determine gaps in correspondence of these parts quarries. The core box is closed by pneumatic pistons and is equipped with extractors. The core boxes are subject to be inserted and removed from the machines core shooter according to production needs.


The most common methods of realization of souls are:
1. Manual to resin: the production is manual, on a desk, with the methods and equipment very similar to those of the molding resin with the only difference that, instead of filling the bracket, here is filled with the core box. This production is more widespread among companies in the sector; production techniques are manual and performed at the bench with procedures similar to those employed for resin molds, the difference is that, instead of filling the bracket, it fills the core box.


2. Ashland (cold process "cold-box"): in this process using silica sand mixed, with automatic mixing, with phenolic resins and polyisocyanates. The set of the component materials is compacted by means of compressed air using specific machines.


3. Shell-molding (hot process "hot-box"): In this process the raw materials and additives (the percentage of resin varies according to the products to be obtained), lubricants and catalysts are compacted within the cash through core blowing machine. Hot surfaces of the case of souls (about 250 °) dissolving the pre-coating of lands favoring the subsequent bonding of individual grains until hardening of the total mass. Once hardened, the soul is removed from the mold using suitable pullers.


4. Insufflation of CO2: after crammed into the mold the mixture of foundry sand and additives (alkali silicates), the hardening is achieved by insufflation of carbon dioxide.


For certain products (for example, special steels) the cores are coated to improve surface strength during casting and solidification.


The soul, once extracted from the box that contained it, is finished by hand to remove any burrs and is stored pending its use in forming