OMCO Metals Slovenia invests in LPDC for bronze casting

Bronze neck rings may be small components, but their production requires a high level of control. They need consistent geometry, a strong surface finish and…

Bronze neck rings may be small components, but their production requires a high level of control. They need consistent geometry, a strong surface finish and reliable casting quality across series production. For OMCO Metals Slovenia, this calls for a process that combines foundry expertise with stable, repeatable production conditions. That is where LPDC comes in. At OMCO Metals Slovenia, Low Pressure Die Casting is used to produce bronze neck rings for OMCO Mould. The process gives the team a dedicated production route for these technically demanding components.

In this article, we take a closer look at how LPDC works, why copper moulds are used, and how pressure, cooling and engineering preparation come together in the process.

How LPDC works

The LPDC machine has a furnace below the mould that contains molten bronze. Low pressure pushes the metal upwards into the mould cavity. The mould fills in about 15 seconds. The pressure then drops. The part stays inside the mould for another 25 to 30 seconds so it can solidify further.

Cross-sectional view of the LPDC machine

Next, the tool rotates and releases the part onto the discharge table. The mould then moves into a graphite bath. This cools and lubricates the tooling before the next cycle. The graphite also helps prevent the bronze from sticking to the mould. One complete cycle takes about 90 seconds.

**Two operators work on the LPDC machine**

Why copper moulds are used in LPDC

The LPDC tooling is made from an alloy containing approximately 98.5% copper. The reason is thermal conductivity. A significant amount of heat has to be extracted from the bronze quickly after filling. Copper transfers heat efficiently, which helps the part cool and solidify inside the mould.

Smaller components such as neck rings are well suited to this process because the heat can be removed quickly enough. Larger castings contain more thermal energy and require a different casting approach.

Engineering before production

LPDC does not remove the need for casting engineering. For every new product, the process starts with the component design. From there, flow and solidification simulations help our engineering team understand how the bronze will move through the mould and how the component will cool.

This information is used to determine the tooling concept and optimise the riser. Trial tooling is then produced and the first castings are evaluated internally. This includes checking the internal structure, porosity and machinability before the tooling is approved for serial production.

Risers remain part of the LPDC process because shrinkage still occurs during solidification. The objective is therefore to minimise the riser while ensuring it can still feed the casting correctly. This increases the proportion of usable material in each pour.

A controlled process for bronze neck rings

OMCO Metals Slovenia currently has four neck ring products running through the LPDC process. The technology is particularly suitable for smaller castings that can be cooled quickly enough inside the metal mould.

The current setup has been adapted specifically for the requirements of our bronze neck rings, including higher casting temperatures and increased cooling demand. This gives us a focused production capability for bronze neck rings within OMCO, combining reusable tooling, controlled filling and engineering expertise in one repeatable casting process.