As one of the first foundries to take advantage of large-scale 3D sand-printing technology, the AMRC Castings Group has enhanced both its capacity and physical envelope.
Capable of producing complex moulds and cores for the oil, gas, aerospace and automotive sectors without the need for dedicated tooling, the technology has been exploited for R&D, pre-production and full-scale production volumes at the University of Sheffield’s Advanced Manufacturing Research Centre (AMRC).
AMRC Castings, which is part of the AMRC and based on the Advanced Manufacturing Park at Catcliffe, now has two additive manufacturing machines for the printing of one-piece 3D sand moulds and complex cores. These moulds and cores would ordinarily require significant capital investment in pattern equipment, and multiple core boxes to be made and assembled.
The ExOne S15 digital mould and core-making system has recently been upgraded by the AMRC Castings Group to incorporate a new, advanced operating system which increases printing speed. Boasting a build envelope of 1,500 by 750 by 750 mm, the machine has also been modified to run on 100% Cerabead, which is suited to higher temperature alloys. The ExOne S15’s sister printer, the ExOne SMax, produces complex sand cores and moulds in silica sand, which is better and cost effective for aluminium and cast iron alloys. This machine also benefits from a larger build envelope of 1,800 by 1,000 by 700 mm and two ‘palletised’ job boxes, allowing rapid set-ups outside of the printing process and hence reduced lead times.
The AMRC Casting Group’s Anthony Kenney says: “As before, both machines print 3D sand printed moulds and cores for use in the foundry industry. However, due to additional investment in process enhancements we have been able to increase capacity and accuracy, and further reduce lead times.”
Kenney explains that thanks to the moulds and cores being made as single pieces, castings with a high degree of both accuracy and geometrical relationship can be produced to DCTG7 (casting dimensional tolerance) flexibly, quickly and accurately. Aside from the more obvious benefits, the hydrodynamic balance attainable from this technology is said to be unrivalled.
“This means, regardless of size, moulds and cores can be made with an accuracy of ±0.3 mm, says Kenney. “Moreover, depending on print density, the typical turnaround time is between 12-24 hours for the SMax, and 24 and 50 hours for the S15. Such performance can be transformational for clients, who typically invest tens-of-thousands of pounds in dedicated, inflexible tooling that takes longer to manufacture than it takes us to deliver a finished casting. In addition, we can easily incorporate minor design revisions without any further costs being incurred.
“As well as utilising this technology to produce high value-added castings, we operate a bureau service, printing moulds for casting by others, directly from their 3D CAD model. The typical lead time for a mould, dependent upon the current production schedule, is five to 10 working days.
“Cti [the commercial arm of the group] can also consult and advise on design and methodology using 3D sand-printed moulds and cores if a foundry has no, or limited previous experience.”
Author: Steed Webzell