Creative thinking and attention to detail assist company to enter large wear parts market.
Prima Industrial Holdings have recently completed and shipped two castings to a North American client that represent the largest castings that the company has ever manufactured in its 80 year history.
“The challenge of the highly engineered large casting market is that you have to get it correct from the beginning otherwise you have a large amount of scrap metal to melt and I don’t have to explain the costs that are associated with that,” said William Price who has recently been appointed Managing Director of the family owned business. William takes over from his father Keith who will now take up the position of Chairman as he begins to hand over to the younger generation management team.
“Prima has been supplying the South African mines and international clients with mining wear parts since its inception in 1937. We have evolved into one of South Africa’s most respected suppliers of steel mill and crusher liners, and have received recognition in the form of numerous export awards and contracts won in a number of international markets including USA, UK, Australasia / Australia, Europe and several African countries.”
Prima Industrial Holdings have made a strategic decision to move into the larger size castings market. This bowl casting used on a cone crusher has a final weight of 10,7 tons
“We made a strategic decision to move into the larger size castings market last year and as a result we were asked to manufacture a bowl and mantle for our US client Optimum Crush. The castings are destined for use on a cone crusher in the Canadian gold mining industry. The bowl has a final weight of 10,7 tons and the mantle 11,1 tons once cast fettled and finished. Previously the largest casting we had manufactured was in the region of 8,5 tons.”
“To take on this project has been a great test for our company and required meticulous planning and team work. From the engineering department to the foundry, quality, fettling and machining departments we had to plan every step. This included engaging our Magmasoft simulation software supplier Ametex. The whole process has galvanised us as a team and we now know that we can accomplish similar projects when called upon, whether it be for a local client or one based internationally,” added Price.
Prima Industrial Holdings have recently manufactured a mantle for their US client Optimum Crush. The casting weighs in at 11,1 tons
“We have been producing crushing machinery wear parts for some time and the castings are core to our business. However, when you are contracted to cast a component over 10 tons there are a number of factors you have to take into account. You have to account for aspects such as melt capacity, crane capabilities, box size and machining capabilities in your feasibility study,” explained David Barbour Prima’s Production Engineer who has been with company for the last three years.
“Integral during our planning stage was to use the services of Ametex and the Magmasoft software to simulate mould filling, solidification and cooling, in advance of the start of production. More critically, the software improves product design by helping to identify residual stresses and distortion, microstructure formation and property distributions in castings.”
“As a result of using the software, in consultation with our client, we did make design changes to the castings to avoid ‘tearing’ of the metal. Particular emphasis was placed on feeder optimisation and control of sand entrainment so that we could minimise molten metal turbulence in the mould and optimise the yield.”
Transfer bogey system
“One of the main constraints we had was that we did not have the melt capacity, or so we thought, on site. After the disappointment of nearly acquiring an arc furnace to alleviate this problem we had to come up with an alternative. This is when Greg Mac Rae, our Quality Manager, suggested we fabricate and install a transfer bogey system so that we could easily transfer molten metal from our small component foundry to our heavy bay foundry and pour simultaneously. The melt capacity of the smaller furnace is 4,5 tons and added to our main furnace of 12 tons it gave us enough molten metal to accommodate the larger size castings.”
The Prima Industrial Holdings’ team that was involved in manufacturing the bowl and mantle wear parts that will be used on a cone crusher that is deployed in the Canadian gold mining industry
“The system is very simple in design but it has saved the company a sizeable amount of costs. We built rails of approximately 30 metres in length to bridge the gap between the two foundries and a mechanised transfer bogey to transport the ladle from the smaller foundry. We also installed a six metre launder to aid the pouring process,” explained Greg Mac Rae.
The castings
“Bulk material processing and handling systems are an integral operation in the mining industry. Crushing technologies for bulk processing applications require components to be cast of high-grade steel and to be recognised for rugged structural integrity. As it is our first attempt to manufacture castings over 10 tons we have created more stringent quality specifications than previously deployed,” said Foundry Manager Cypi Kyalu.
“After finalising our 3D model it took six weeks to produce the patterns and mould setup took about five days. Melting and pouring was relatively short compared to planning and preparation and the cooling off period was about four days. The machining was done on our own vertical boring mill that has a four metre table.”
“Other interesting facts were that we used about 16,5 tons of metal per casting and the weight for the metal, boxes and sand was about 40 tons per casting. After fettling and removing feeders we would still remove between 600 and 800 kilograms of metal during the machining process.”
“The bowl and the mantle that we have manufactured only represent six percent of the total weight of the cone crusher that is one of three of its kind used in the world. The castings are on the water at the moment and should be put into production early next year,” said William Price.
“Going forward, we are looking at manufacturing at least two of each casting per month as the cone crusher wear parts such as these are changed every four weeks. As a team we have broken barriers to deliver and we are confident that our client will recognise this,” added Price.
For further details contact Prima Industrial Holdings on TEL: 011 421 6911 or visit www.primafoundry.com
