Sand casting by experts at Haworth Castings

Published - 29th Apr 2024

A quick look at the expertise in our foundry team 

At Haworth Castings we provide end-to-end technical solutions. From design for manufacture (DfM) support to delivery of fully-machined and tested components, our experts call on their experience and knowledge every day to ensure that your high-quality sand castings meet or exceed specifications.   

In this blog, we’ll take a quick look at some of the experts in our foundry, and how their skills ensure high quality, precision sand castings. 

An expert foundry team 

Over 20 people work in our busy foundry, about the same number as work in our machine shop and offices. From manager to foundry operatives, our team members have many years’ experience in casting.  

We continually build on this expertise via our skills matrix, rotating teams between workstations and helping every member of our foundry team to expand their knowledge and share their expertise with others. Customers benefit from knowing that every person involved in sand casting at Haworth Castings has a breadth of knowledge that helps them deliver precision cast components for performance-critical industries. 

Designing the best running system for a good pour 

Technical Manager Krzysztof Wolszczak enjoys the challenge of delivering technically demanding castings. “Now that software gives designers more freedom to develop complex 3D designs, we take on more and more complex jobs. The running, feeding and filtering systems need to be spot on to deliver high quality, accurate sand castings.” 

Krzysztof works closely with Haworth Castings’ tool designer on the running system for each sand casting. A well-designed running system is key to ensuring that molten metal fills the sand casting completely and at the optimum rate. Their design is verified by simulation software, making the best use of both practical experience and the latest technology. 

Preparing the metal perfectly for the pour 

Our foundry experts add bars of metal to the furnace for melting. They must ensure that the metal is heated to the right temperature for casting. For aluminium alloys used in sand casting this is generally between 700° and 750°C.  

Once the metal has reached the optimal temperature, modifiers are added (to enhance the structure and reduce shrinkage) along with grain refiners (to control the size of the grain, helping achieve consistent solidification and preventing defects). Quantities are determined according to the weight of molten aluminium. 

Our foundry experts then degas the metal mechanically to remove any hydrogen that may have been introduced through atmospheric humidity during melting. Hydrogen in the melt can cause porosity in the casting. A hand-held rotary degasser is used to purge the hydrogen from the metal using nitrogen. 

A sample of molten metal is poured into a die to harden, and tested to ensure that it meets specification. Only then can our expert foundry team begin the pour. 

An expertly controlled pour 

At Haworth Castings, all our pouring is done by hand. Our expert foundry operatives use a ladle to remove molten metal from the furnace and pour it carefully into the sand mould. Multiple pouring points may be used, due to the weight of the casting or to reduce the risk of premature solidification in thin wall sections.  

The speed of pouring and entry into the running system has a critical effect on the quality of the casting. If poured too slowly, the molten metal may not reach all parts of the mould cavity due to a lack of pressure and premature solidification. However, if the metal is poured too quickly, this can lead to turbulence, which may cause voids and inclusions in the castings. Our skilled foundry team must carefully control the pour to avoid such issues. 

The handling of molten metal is not without risk.  We have comprehensive measures in place to protect our team, including: 

• regular and ongoing training for our foundry and management teams 
• specialist personal protective equipment (PPE) 
• regular servicing and maintenance of our machinery and tools 
• internal and external health and safety audits 
• regular reviews of our risk management processes and related COSHH (Control of Substances Hazardous to Health) assessments. 

Expert sand casting at Haworth Castings 

We are proud to supply precision sand castings for performance-critical applications. This is only possible because we have expert teams at every stage of the manufacturing process, working to ensure that your sand cast components are properly designed and cast. 

With over 60 years of experience and knowledge, we have the skills and tools provide solutions to the most complex technical aluminium casting challenges. Please get in touch for more information. Contact Haworth Castings on 01794 512685 or email sales@haworthcastings.co.uk.