Choosing the right casting process

Published - 10th Feb 2016

At Haworth Castings, we use two main processes, namely sand casting and gravity die casting. The choice of casting process is generally determined by the production volume and the customer’s budget. There are some other fundamental differences between these processes that also influence this decision. In this blog, we take a look at each of these techniques in turn.

Sand casting

At Haworth Castings, sand casting accounts for more than 95% of our work. As we’ve explored in our earlier blogs, this process involves pouring the molten metal into a sand mould.

Sand casting is a relatively cost-effective process, with quick set-up times, so it is ideal for prototyping or small production runs. It can be used to produce components of just about any size and shape, from the most basic to those of far greater complexity. The overall dimensional accuracy is good and an excellent surface texture can be achieved with the right finishing.

The sand can also be recycled, which offers both environmental and cost benefits. Indeed at our foundry in Romsey, we recycle 99% of the sand from our casting work. The patterns used to create the mould can also be reused many times, with minimal wear during production. This makes sand casting the most suitable option for many of our customers.

Gravity die casting

We use gravity die casting for medium-volume casting projects. This process involves pouring molten metal into reusable cast-iron dies under the pressure of gravity.

The main benefits of this process include:

• cost effectiveness on high volume production
• excellent dimensional accuracy
• higher tensile strength and better mechanical properties than sand casting
• minimal finishing

The main disadvantage is the cost of the tooling – which can be two to three times higher than the patterns used for sand casting. The metal dies are more expensive to produce than the sand casting patterns so a high production volume is needed to make this process economical in the long term.

Want to find out more about our casting capabilities? If so, please email us today at: sales@haworthcastings.co.uk or call +44 (0)1794 512685.