Process improvements in sand casting over the past 60 years (part 1)

Published - 18th Jul 2018

The history of sand casting stretches back many thousands of years, as we’ve explored in previous blogs. The basic principles involved in sand casting remain unchanged, but new technologies have helped to bring about many improvements over the past few decades.

In the first of three blogs, we look at how process improvements have enabled us to develop our capabilities and offerings to customers since Haworth Castings was formed in the 1950s.

3D modelling for pattern making

The first essential part of the sand casting process is, of course, pattern making. As we’ve mentioned previously, top-class patterns are vital to create top-class castings, so the design is paramount.

Half a century ago, pattern makers used paper designs and their own manual calculations to make the patterns. Today, our pattern maker uses 3D modelling software to create highly intricate and accurate patterns. The shrinkage allowance is automatically ‘factored in’ – removing the risk of human error.

Using the right sand

The type of sand used at Haworth Castings has also changed over the years. Until the 1980s, green sand was used. This type of ‘damp’ sand typically included bentonite clay and water. It had to be placed in metal moulding boxes until the molten metal was poured in. The patterns and running systems were then added manually by the foundry team. 

Green sand is still popular in the casting industry but, at Haworth Castings, we now use a high-grade silica sand mixed with resin binders. These days, the sand is so firm that it can pushed into the moulding box containing the pre-assembled pattern and running system.

This helps to create a more robust mould as well as providing an improved surface finish and better dimensional accuracy on the castings.

In the next blog, we will be looking at the introduction of new additives and improved core making.

Want to find out more about our capabilities? Please call us today on +44 (0)1794 512685 or email us: sales@haworthcastings.co.uk