An Overview of Gravity Die Casting

Published - 17th Feb 2021

Gravity die casting, sometimes referred to as a permanent mould casting, typically uses alloys of non-ferrous materials such as, aluminium, copper, magnesium and zinc. As implied by the name, gravity die casting relies solely on the forces of gravity to fill the mould with molten metal. This differs from other casting processes which use an applied force or pressure.

Gravity die casting process

To begin the process, the die is heated and sprayed with a refractory coating. This coating helps control the temperature and assists in the removal of the casting from the mould. Molten metal is then poured into the cavity of the die which fills under the forces of gravity. Once the die is filled, the metal is allowed to solidify, after which the die is opened and the cast parts are removed, either by hand or using ejector pins. The final step is to remove any excess material from the casting, including runners, gates, sprues and flashing. The casting then undergoes post-processing to create the finished product that goes to our customer.

Interesting facts about gravity die casting:

• Cast iron is the primary material used in the production of the dies
• Inserts, usually manufactured in metal or sand, can be incorporated into the die to produce internal features
• As the molten metal solidifies so quickly, the production process is quicker than other casting methods
• Gravity die casting is a good option for producing small castings in medium volumes when compared to sand casting
• Smoother cast surface finishes can be achieved compared to sand casting
• Initial tooling outlay is greater than it is for sand casting but piece prices are lower

As part of the Expromet Technologies Group and in collaboration with our sister company, Haworth Castings, we can offer gravity die castings manufactured both in the UK and overseas, accompanied by the full range of post-casting services including machining and finishing solutions.

At Investacast, our experienced design engineers work with you to find exactly the right solution for your application. Whatever your casting needs, Investacast can support you from initial concept phase, through prototyping, ramp-up and full volume production.

If you would like further information about the content of this blog or to understand more about our casting capabilities, please contact Investacast +44 (0)1271 866200 or email [email protected].