The University of Sheffield Advanced Manufacturing Research Centre (AMRC) with Boeing is a world-class centre for advanced machining and materials research for aerospace and other high-value manufacturing sectors. Now boasting more than 80 member companies, this partnership between industry and academia has become a model for research centres worldwide. http://www.amrc.co.uk
Since 2013, the AMRC has targeted the development of a Grinding Centre of Excellence to complement the existing milling and turning capabilities that have been established within the Machining Group. As grinding and surface finishing operations can account for 20-25 per cent of the cost on all machining operations, the Grinding Centre of Excellence’s vision is to extend and enhance its capability, both in terms of equipment and resource, to a level required by the existing partnership.
A major advancement in the AMRC Grinding Centre of Excellence’s development is the recent installation of a cutting-edge Studer S41 CNC universal cylindrical grinding machine.
Advanced Manufacturing Research Centre with Boeing technical fellow, Dr David Curtis explained. “Previously grinding has mainly been regarded as a means of machining for final dimensional accuracy and of achieving the workpiece’s required surface finish. Although, thanks to recently developed techniques which greatly increase material removal rates, this perception is rapidly changing.
“The AMRC with Boeing’s grinding and surface finishing team have the capabilities and expertise to improve performance and quality across the range of grinding operations, with a particular focus on aerospace components. Process areas include cylindrical grinding, surface and profile grinding, multi-task grinding, hybrid grinding, gear grinding and mass finishing. Our current grinding related research areas include - cost modelling, environmental impact, hardware / applications development, process optimisation, process control as well as training and support functions. In addition our studies involve coolant, wheel technology and wheel dressing.
“To aid our research in these areas and to further enhance our grinding capabilities we began a search for a high-end cylindrical grinding platform in 2015. Having considered a couple of options, a visit to the HQ of Studer, part of United Grinding, in Switzerland and a very successful demonstration of a Studer S41 CNC universal cylindrical grinding machine, convinced us that the Studer S41 was the answer to our needs.
“In addition to boasting a higher level of stability and precision than the alternatives we looked at, the Studer S41’s multiple wheel-head capacity and overall flexibility, allowed it to cover the vast majority of our demanding needs.
The S41 wheel-head has 4 wheel-mounting positions and any combination of external and internal grinding spindles is possible. The AMRC S41 has been supplied with the optional centre height of 325mm !
“To enable our new Studer S41 to not only accommodate all current workpieces, but also any larger, future work, we ordered the machine with an increased centre height of 325mm, allowing a swing of 650mm. We also specified the inclusion of high-speed grinding (140m/s), thread grinding, out-of-round grinding, as well as the inclusion of a special high-pressure coolant system that is suitable for use with emulsion and neat-oil. The target was to specify a machine tool platform with research flexibility as well the ability to engage with a range of industrial applications.
“Our Studer S41 is now actively engaged in a number of important projects including research into the grindability of materials and the study of automated process control for aerospace applications. Also, rather than users relying on the data supplied by the manufacturers of grinding wheels, we are currently looking to develop a standard wheel test to allow all grinding wheels to be benchmarked against each other. So far, although some other wheels have delivered good results, we have been particularly impressed with the high stock removal rates delivered by 3M’s Cubitron grinding wheels.
“As United Grinding has become a Tier 1 Partner with the AMRC, our Studer S41 is also occasionally used as a demonstration resource for prospective Studer customers.”
The S41 is based on a Granitan® S103 machine bed due to the advanced material’s excellent damping characteristics and favourable thermal behaviour. The large distance between the S41’s guideways and its rigidly constructed slides, provide further precision.
The advanced machine boasts a wide range of advanced technical features, such as high-precision axis drives with linear motors, extremely fast direct drive of the B-axis and a large selection of wheelhead variants, it also features Studer’s revolutionary StuderGuide® guide-way system.
Thanks to a standard centre height of 225 or 275 mm and a distance between centres of 1000 or 1600 mm, this latest generation CNC universal cylindrical grinding machine is able to efficiently undertake the vast majority of daily grinding tasks. The S41 can also be configured as a single-purpose machine for large batch production use.
The S41’s impressive speed and precision capability is the result of the perfect interaction between a large number of different factors. All of the machine’s modules are ideally suited to each other and produced with customary Studer precision, whilst components involved in defining precision are temperature-stabilised.
The use of intuitive StuderWIN user interface and the advanced StuderGRIND software module create a stable programming environment for the operator and further contribute to the machine’s efficiency. A PC is integrated into the CNC control providing the ability to integrate in-process gauging and sensor technology for process monitoring. In addition contact detection and automatic balancing systems in the control enable standardized programming of the different systems. Software for an internal loading system is also integrated in the control.