The foundry process is centuries old, and nowadays over 110 tonnes of castings are produced every year, according to the European Foundry Association. Foundry is more than just making metal parts for engine, rail and pipe components. Nowadays, around 90% of all manufactured consumer products use metal castings for their module parts – the automotive industry is probably one of the largest industries which depend on the foundry sector.
A foundry or metal factory casts metals into shapes by melting them down and pouring the molten liquid into a sand, ceramic or metal mould to form geometrically complex parts. The metal is then allowed to cool and the liquid solidifies. The shaped metal, or casting, can now be used to produce more difficult and uniquely shaped products or parts.
All major metals can be cast. The most common metals processed are iron, aluminium, steel and copper-based alloys but other metals such as bronze, brass, magnesium and zinc can also be used to produce castings so that parts of any desired shape and size can be formed.
There are several stages involved in the casting process which include making the pattern, melting the metal, pouring the molten liquid, the cooling process, removing the metal, cleaning the parts and the inspection process.
Moulds are carefully shaped with a pattern, which is a wood or metal replica of the object to be cast so that the final shape corresponds fully with the mould used. Usually, moulds are made using silica sand, but they can be created using different materials depending on the type of metal being cast.
UK foundries are variable in size with some producing high quality and specialist parts for automotive and aerospace industries. The smaller-scale ones often make individual and custom pieces to meet their customer’s needs.
Clean, high-quality silica sand has been used to produce moulds for many years in the Foundry industry. These moulds are used to produce a wide variety of metal castings and for metal such as steel, which has a very high melting point, high-grade pure silica sand needs to be used. For cast iron, copper and other alloys, which have a lower melting point, lower-grade sand can be used.
Later in the process, the silica sand is removed from the casting where it is recycled in the foundry or used in the production of concrete or asphalt. Sand is an essential raw material for many manufacturing processes but the most demanding ones are by far foundry applications.
This is the last stage in the casting process and it often involves grinding or sanding the component to achieve the desired final shape and finish. To ensure a tightly controlled finish, many castings are machined in milling centres, creating better dimensional capabilities.
The dust produced when processing casting sand contains silica and when dry, it produces respirable crystalline silica or RCS. Some foundry workers, working with silica sand, can inhale the RCS dust and this can lead to a serious health condition called silicosis. Silicosis is a disease commonly seen in industries such as quarries and foundries, where there is increased exposure to silica dust.
The amount of dust, particularly respirable and silica, is a real concern for foundry workers and research shows that workers are particularly at risk from breathing in finer airborne particles. It is imperative to try and keep dust exposure to a minimum but even when this is achieved, workers are still at risk. Heath and Safety and operational processes should be put in place to keep the risk to an absolute minimum and accurate records and safety checks should be regularly maintained.
Depending on the foundry, workers can be exposed to other hazardous substances including aluminium, lead and chlorine. Solvents can also be a risk if the foundry is involved in spraying processes.
Ferrous foundry particle exposure can lead to respiratory problems including asthma and is, therefore, an occupational hygiene concern.
Silicosis can develop among workers who have many years of exposure to silica dust and new evidence suggests that long term exposure can increase the risk of getting lung cancer. Consequently, the exposure risk must be reduced to as low a level as is reasonably possible. Employers have a duty under the Control of Substances Hazardous to Health (COSHH) Regulations 2005, to asses and control the health risks to their workers of hazardous substances in the workplace.
When it comes to removing dust, in contrast to using compressed air, which can be very dangerous, blower-driven air has been shown to provide a safer and highly effective means of removing fibres, dust and water from people, surfaces and environments.
By using blower-driven air, the JetBlack Safety range of personnel Cleaning Booths can provide a safer and more convenient solution for personnel clean-down. What’s more, the full product range has been designed as an easy-to-use alternative to compressed air, as the low pressure, high-velocity air produced poses no threat to the safety and can be directed at almost any part of the body. This gives organisations peace of mind and users a safer solution for all de-dusting operations.
The JetBlack Safety Cleaning Booth is particularly suited to agitating and removing sand and metal particles from employees’ work clothes; a process which typically takes no longer than 30 seconds. The dust is then safely extracted away from the user and collected in the HEPA H14 extractor.
Personnel Cleaning Booth applications include: