When people think about metal casting, they usually picture molten metal filling a mould. What often remains unseen is the role of cores. In many applications, these internal elements determine whether a component will function as intended.

In a foundry, a core is a sand-based component placed inside the mould to create internal geometries. Cavities, channels, internal walls and hollow sections all depend on these internal shapes. Without them, cast parts would be limited to simple, solid forms.

At OMCO Metals, cores play a central role in producing complex cast components. They define internal dimensions, wall thicknesses and functional spaces that cannot be formed by the outer mould alone. This makes core design and execution a critical engineering discipline rather than a secondary step.

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Balancing strength and permeability

One of the main challenges in core making is balance. The sand structures must be strong enough to withstand the thermal and mechanical forces of molten metal during pouring. At the same time, they must remain porous so gases can escape during solidification. If gases are trapped, defects such as porosity or surface imperfections can occur.

Material choice, sand composition, binders and curing processes all influence this balance. Small deviations can already have a significant impact on casting quality and repeatability.

Casting Core Design Starts Before Production

The design phase starts long before a single mould is produced. Engineers analyse 3D geometries, evaluate metal flow and solidification behaviour, and determine how the internal structures will be positioned and supported inside the mould.

Advanced simulations help predict risks such as deformation, hot spots or insufficient feeding. This allows adjustments early in the process, which is essential for components with tight tolerances or functional requirements such as leak tightness.

Execution on the shopfloor

Even with a well-designed solution, execution remains critical. Cores must be handled, placed and verified with care. Experience on the shopfloor plays a decisive role, as small shifts or damage to casting cores can directly affect internal geometry and final performance.

Once the metal has solidified, the sand-based casting cores are removed, leaving behind the internal structure of the metal casting. The casting cores themselves disappear completely, but their influence remains embedded in the final part.

An invisible but decisive process step

The sand cores break down and burn out during the process, and are removed after solidification. What remains is the geometry they created, internal channels, cavities and functional spaces formed directly in the metal.

That is why core making is often the deciding factor between a casting that performs and one that does not. At OMCO Metals, core making is treated as a key competence, combining engineering expertise, process control and craftsmanship to deliver complex and reliable metal castings.

Contact us

If you want to discuss a complex part or internal geometry challenge, contact our team at sales@omcometals.com

​Glass is one of the most recyclable materials in the world, but the tools that shape it also play an essential role in building a sustainable future. At OMCO Metals, we create materials for the glass mould industry that are designed and managed with sustainability at their core. This ensures that valuable resources are preserved and reused for as long as possible.

Reusability and repairability

Our moulds are not single-use tools. Throughout their lifecycle, they are carefully maintained, reconditioned, and repaired. When moulds begin to wear down or show signs of damage, they are not immediately discarded. Instead, they undergo a meticulous reconditioning process that restores their functionality and extends their useful life. This reduces waste while ensuring consistent performance for our customers.

Material recovery

Even when glass moulds eventually reach the end of their lifecycle, they do not become waste. Instead, they are reintegrated into the production loop through material recovery. This involves:

• Collection: Used moulds are returned from our customers’ plants.
• Reformation: The valuable metals are melted down and reformed into new moulds or other products.
• Loop Continuity: This closed-loop approach reduces the need for new raw materials and minimizes environmental impact.

A circular approach to manufacturing

By combining reusability, repairability, and material recovery, OMCO ensures that the resources used in mould-making are continuously recycled. This approach not only strengthens the durability and efficiency of our products but also contributes to a more responsible and eco-friendly manufacturing process.

At OMCO, we believe in a future where product and process exist in harmony with the planet.