What is a sand casting running system?

What is a sand casting running system?
Choosing the right running system in sand casting

In sand casting, a running system is a series of connected channels that allows the molten metal to flow and fill every area of the mould cavity. The running system allows us to control the liquid flow, turbulence, cooling rate and shrinkage.

Traditional running systems

Typically, ring runner systems are used and these feature several elements:

  • Pouring cup – a funnel that allows metal to be poured into the mould at a uniform rate
  • Down sprue – a vertical passageway (attached to the cup) through which molten metal enters the mould
  • Filters – to remove impurities and reduce the risk of casting defects
  • Runners and gates – channels that connect the down sprue with the risers and convey the molten metal into the mould cavity
  • Risers – vertical cylinders that provide a continuous flow of molten metal into the mould. Risers compensate for shrinkage as the molten metal solidifies.

These systems allow several entry points for the molten metal to enter the mould. 

This type of running system is machined into the mould by the pattern maker at the start of the design process. It would not be practical to add this during the casting process as the sand cures too quickly.

Kalpur pour technology

In recent years, we have used Kalpur direct pour technology as an alternative to the conventional runner and gating systems.

The Kalpur unit acts as an all-in-one pouring cup, filter and sleeve. Using this technology, foundry engineers can pour the molten metal directly into the mould at a single point. The thermal insulating sleeve optimises the metal temperature and eliminates the need for complicated gating systems.

Other benefits of this technology:

  • less sand and metal are required – which leads to lower costs and less scrap
  • higher yield – from the simplified running system and more room in the mould for further castings
  • time savings – as the pattern maker does not have to incorporate a complicated running system
  • reduced finishing – due to fewer runners and risers

As a result, Kalpur technology delivers huge cost and environmental benefits for our customers. However, Kalpur units are not suitable for all casting work and a number of factors determine whether this newer technology or traditional running systems are used:

Each casting job requires a different approach and we tailor our methods entirely to suit our customers’ requirements.

If you would like any information about our casting capabilities, please email us on sales@haworthcastings.co.uk or call us on +44 (0)1794 512685