Celebrates 100 years of operating from current location in Germiston.
In 2019 Thomas Foundry embarked on a project to upgrade and modernise their melting department, which had furnaces that had given a return on investment to the company, many times over. Nevertheless, there comes a time when the capital investment decision has to be made otherwise you start to lose clients because of late deliveries and poor quality. Add to this the pressure of trying to be price competitive with old technology and equipment, and you soon realise you are fighting a losing battle, especially if you can’t source spares to keep your furnaces operating.
“There are multiple factors for foundries selecting a new melting furnace, but to achieve competitiveness it is critical to select equipment that matches the business’s needs. Our 5 ton Radyne furnaces did so when they were purchased as do our new Inductotherm furnaces that we have installed over a phased period recently,” said Thomas Foundry CEO Clayton Anderson.
Thomas Foundry installed and commissioned two Inductotherm 6 ton furnaces in February 2024. The Inductotherm equipment was supplied by Cerefco
“For melt shops using induction equipment optimising melting cost-per-ton starts with minimising kW and kVA demand. However, to minimise exposure to the high-power rates, these melt shops should optimise operating and maintenance practices and evaluate the equipment and generator systems in use, so they too are being optimised.”
“Environmental impact and use of energy and materials are relevant topics in companies. To achieve energy savings and enhance environmental performance, managers can invest in technologies (technical measures) and/or implement management practices (low-cost and non-technical measures).”
“By examining a typical melt shop and its energy usage you will find that melting represents the highest percentage of energy consumption in a foundry. Melting typically accounts for over 50% of the overall foundry energy usage and this figure could go up to 80% depending on the foundry’s efficiencies. Therefore, the melt shop offers the best opportunity for energy demand and usage cost reduction.”
“For many foundries, the largest energy savings can be realised by replacing their current melting equipment with equipment that is more productive and energy efficient. But whether or not you are ready to make that investment, you should investigate operational changes that may also produce significant cuts in your power use. Many of these can be made at little or no cost.”
The Inductotherm furnaces have 3 000kW Power-Trak eb power and control systems which include a constant line power factor to eliminate power factor penalty charges and a voltage-fed inverter design for high-efficiency and faster melt rates
“Foundries selecting a new furnace will consider production goals, equipment maintenance, safety standards, and product lifespan, among other factors, but finally the choice will come down to identifying a furnace that can match a high-throughput target while withstanding the foundry’s harsh environmental conditions.”
“Optimising your metal melting system to reach the lowest possible kilowatts (kW) and kVA of demand as part of your overall energy management programme is critical to competitiveness in an industry where energy costs are a constant concern. The importance of melt shop power supply utilisation, efficiency and performance, and how it impacts power demand should be examined carefully. It directly influences the connected kW or kVA of demand for a given production rate. By increasing your melt shop power utilisation rate, you will increase and maximise the volume of metal poured per kW and kVA of demand. There are various ways that you can review these factors within your own foundry to find additional opportunities for conserving melt shop energy demand and usage.”
New melt platforms
“New techniques have emerged to improve the value of castings by improving the efficiency of molten metal treatment. However, it is just as important getting your pouring, transporting of the molten metal and other logistics before the casting is manufactured, such as the supply of scrap metal, correct.”
The VIP Power-Trak eb System offers enhanced efficiency partially because it does not require a load matching transformer – allowing more energy to be delivered directly to the load. Additionally, the eb system is electrically isolated from the high voltage utility line as well as ground via a dedicated primary line isolation transformer. This allows the VIP unit’s Ground Leak Detector to constantly monitor the entire system for ground leakage
Thomas Foundry have also installed an ABP Systems furnace charging unit which is housed on the melt platform. The furnace charging systems convey scrap/charge materials through vibration by using a pair of out of balance motors controlled via a variable control system to provide a rapid or trickle feed into the furnace to minimise damage and wear to the furnace lining
“We introduced our new Inductotherm one ton furnace and Inductotherm 500kg furnace in the first quarter of 2021. Although they had essentially been purchased to replace ageing equipment, they also gave us the opportunity to manufacture smaller castings and be a lot more flexible in the smaller size casting market.”
“We had reached a stage where the smallest size furnace that was in use had a three ton capacity. This limited us in a number of ways with the biggest impact being when we were called to cast smaller size castings or a smaller amount of castings. For example, if we only had a total weight of one ton of metal to pour it was not viable to heat up three tons of metal. So the castings had to wait until we got in other orders to cover the other two tons of metal and this would stretch out our lead times. With longer lead times you are not going to score brownie points with clients who always want their castings today even though they only give you the order tomorrow.”
“Having to maximise our furnace capacity also presented its challenges when running trials for new clients or new components for existing clients. Again, the lead times were a problem because again we had to fill the furnace capacity.”
“Both units are supplied with Inductotherm Vortex high-velocity extraction hoods which are designed to more effectively extract fumes during various operations such as charging, slagging, temperature taking, sampling, melting, holding, pouring and lining push out. They are connected to our existing extraction system.”
Thomas Foundry have also installed a 50kg batch mixer and sand silo and two new gassing stations that have been manufactured by RC Electrical Systems. “The one station can accommodate core boxes of 500mm by 500mm by 500mm and the other slightly smaller accommodating core boxes of 300mm by 300mm by 300mm.”
“Then there was the time it took to get the metal up to optimal melting temperature as well as the co-ordination and timing between the melting department and the moulding teams. If you encounter a problem with a mould, you could have metal stewing in a furnace, which does not make the melting guys happy, notably if it is close to the end of a shift. So yes, our management of metal pouring was not ideal especially if you consider that one of our old five ton furnaces could take five hours for the charging and pouring processes.”
“The installation of the two new smaller Inductotherm furnaces lifted these restrictions and challenges for us in this department.”
Logistics and structure: 100 years in Germiston
“Thomas Foundry moved into its current site in Smits Street, Germiston in 1924 under the name of East Rand Engineering. In 1969 Brian Thomas joined the company as the Managing Director. Two years later, in partnership with Reg Pilliner, he bought out the owners East Rand Engineering, who had decided to close the company. In 1981, Brian Thomas acquired full control of the business when he bought out Reg Pilliner’s shares.”
“We have been operating from this location in Germiston for 100 years. You can imagine how many changes have taken place on the foundry floor, some recorded and others not, in that period. This did present a challenge to us when deciding to position our new furnaces to give us the maximum operational optimisation in terms of logistics and flow.”
“We also had to take into account of where our Endeco Omega Sinto sand plant, including reclamation, is positioned, which we installed a few years back in 2014.”
Extraction equipment supplied by RC Electrical Systems
The batch mixer and sand silo
“Besides the other challenges I have mentioned we have never been able to effectively use our overhead cranes and we also took this into account when we began our planning back in 2017/18.”
“We decided on raised melting platforms which meant that we would have to undertake a major civils redevelopment to allow for reinforcing, the moving of columns that hold up the roof and in the case of the two 6 ton furnaces, the construction of a basement to house the Inductotherm VIP® Power-Trak® eb System and other associated equipment.”
“The four furnace systems from Inductotherm arrived in April 2020 and we immediately began the construction work to house the two smaller furnaces. These two furnaces were installed and commissioned in February 2021.”
Two Inductotherm 6 ton furnaces
“We only began last year with the construction work to house the two Inductotherm 6 ton furnaces and we installed and commissioned them in February 2024. The furnaces have 3 000kW Power-Trak eb power and control systems which include a constant line power factor to eliminate power factor penalty charges and a voltage-fed inverter design for high-efficiency and faster melt rates.”
Recently manufactured cores
“The Inductotherm 6 ton melting furnace assemblies include a proven ‘free-breathing’ coil design using thick-walled copper tube for maximum power efficiency, a dual motor hydraulic supply, solid copper power bus assemblies and a DI water cooling loop.”
“The VIP Power-Trak eb System offers enhanced efficiency partially because it does not require a load matching transformer – allowing more energy to be delivered directly to the load. Additionally, the eb system is electrically isolated from the high voltage utility line as well as ground via a dedicated primary line isolation transformer. This allows the VIP unit’s Ground Leak Detector to constantly monitor the entire system for ground leakage.”
“Both units are supplied with Inductotherm Vortex high-velocity extraction hoods which are designed to more effectively extract fumes during various operations such as charging, slagging, temperature taking, sampling, melting, holding, pouring and lining push out. They are connected to our existing extraction system.”
“Although the Inductotherm furnaces systems have essentially been purchased to replace ageing equipment, they will give us an extra 2.5 ton capacity.”
Thomas Foundry purchased a Bruker Q4 Polo spectrometer from SPS in January 2024
Furnace charging
“We have also installed an ABP Systems furnace charging unit which is housed on the melt platform. The furnace charging systems convey scrap/charge materials through vibration by using a pair of out of balance motors controlled via a variable control system to provide a rapid or trickle feed into the furnace to minimise damage and wear to the furnace lining.”
New equipment from RC Electrical Systems
“We have also installed a 50kg batch mixer and sand silo and two new gassing stations that have been manufactured by RC Electrical Systems. The one station can accommodate core boxes of 500mm by 500mm by 500mm and the other slightly smaller accommodating core boxes of 300mm by 300mm by 300mm.”
Metal mix
“This upgrade and investment has also given us the opportunity to assess what metals we melt, bearing in mind we want as little contamination as possible. We have narrowed the range down to carbon steels, low-alloy steels, high-chrome irons, manganese steels and grey and SG irons. Stainless steel and the exotic irons that we were offering became too disruptive to our production schedule.”
“It was not hard for us to make these decisions. We needed to replace our 30-year-old plus furnaces that had served us well over the years but had reached a stage where they were no longer economically viable. Added to the equation was sourcing OEM spares to keep them operating is a real difficulty,” said Anderson.
“The risk-management perspective and the shear frustration from the staff had also reached its maximum tolerance. And, at the end of the day, the good quality of the castings that we pride ourselves on manufacturing was being called into question.”
For further details contact Thomas Foundry on TEL: 011 873 3200 or visit www.thomasfoundry.co.za
