When safety critical pump manufacturer Apex Pumps (Apex) hit problems with castings suppliers, the Bristol-based company decided the only solution was to start making them itself.
Now, thanks to the help of Castings Technology International (Cti), part of the University of Sheffield Advanced Manufacturing Research Centre with Boeing, those problems are a distant memory and Apex is looking forward to a future where it could start supplying others with castings, as well as pumps.
Apex began life designing and manufacturing centrifugal pumps in the 1980s, developing the specialist skills needed to supply high quality, tailor-made pumps to companies in the offshore oil and gas, chemical processing and power generation sectors.
At first, the company bought all its castings from foundries in China and the UK, but as it moved into safety critical markets, it became increasingly difficult to find suppliers capable of meeting its quality and delivery requirements.
“We were struggling to get the levels of support and delivery times we needed,” says Andrew Simpson, who now runs the company’s foundry, Precision Alloys Ltd (PAL).
“We needed a higher specification product, delivery times were going up and we faced quality issues which led to further delays if castings had to be remade. Suppliers also couldn’t provide the certification our customers were starting to request.”
What’s more, Apex faced significant costs when it needed to modify pumps in its range to meet customers’ specific requirements as wooden patterns had to be modified or remade.
Cti – based at South Yorkshire’s Advanced Manufacturing Park – was able to provide Apex with all the technical support it needed to set up its own ‘Micro Foundry,’ while the Manufacturing Advisory Service provided support for a feasibility study.
Cti’s support spanned everything from a licence to use its Replicast® process technology to advice on equipment and environmental consultancy services that enabled APEX to secure planning permission for the foundry on a small industrial estate, surrounded by new homes.
Its staff provided manufacturing drawings and designs for casting boxes, supplied a vibrating table in kit form and helped PAL find reconditioned melting furnace and burn-out furnace, trained PAL’s workforce, none of whom had worked in a foundry before, and were on hand when PAL made its first castings.
“This is a real SME success story and shows the depth of support we can offer,” says Cti’s Will Jeffs.
“PAL has doubled output since it started and is now able to make castings from metals including super duplex alloys, which a number of foundries that have been going for 50 years or more would struggle to do.”
Rapid response, improved quality, reduced costs and increased capabilities with Replicast®
Cti’s Replicast® technology allows PAL to replace expensive wooden patterns with dimensionally precise replicas cut from solid blocks of polystyrene foam by a CNC machine, using data from Apex’s CAD system.
Each polystyrene replica is dipped in a tank full of a special slurry to create a ceramic shell which is significantly thinner than a traditional investment casting shell but with the same excellent internal surface finish.
Shells are fired, removing the foam, put in casting boxes and surrounded with refractory sand. The boxes are shaken on a vibrating table before air is drawn out of the sand to create a firm support for the shell, after which molten metal is poured in.
Replicast® allows Apex’s fluid engineers to modify designs to suit customers’ needs without the cost of having patterns made or modified, meanwhile.
Its flexibility allows PAL to make castings with a vast range of sizes and complexities, including the smallest pump impellers, large pump castings and bearing housings.
PAL uses Replicast® technology to make castings weighing up to 100kg, but the technology has been used to make castings weighing 800kg and above – well above the limit for comparable conventional investment casting methods.