Advanced Manufacturing Sheffield Ltd (AML) is an advanced sub-contract machinist that specialises in the manufacture of complex hard metal parts. It works collaboratively with major players in the aerospace industry and delivers parts on a reoccurring basis to these Primes. AML's processes enable it to cut metal significantly faster than many other suppliers, yielding benefits to its customers at the new product introduction phase. The company's advanced methods eliminate the need for incremental learning changes to processes, delivering instantaneous returns for its customers, saving costs which would normally need to be recovered over several years. These techniques, combined with the exceptional flexibility that the Mori Seiki machines offer, has seen AML grow substantially.

Formed in 2008, it started by offering manufacturing, training and consultancy to aerospace Primes and Tier 1 suppliers. However, in 2010, it extended its capabilities with its own manufacturing facility, producing critical parts such as blades, disks, blisks, and combustion casing components. It is also a Tier 2 member of the The University of Sheffield Advanced Manufacturing Research Centre with Boeing (AMRC) and benefits from a close technological relationship with the organisation, to continually enhance its advanced machining capabilities.

Dr Gareth Morgan, Managing Director of AML was one of the first ten people to work at the AMRC when it was formed in 2001 and, while there, used his knowledge and experience to develop many machining projects from concept validation to qualification of the full production process and its metrics. The realisation that the AMRC could not offer commercial manufacturing to its customers led him to form AML to deliver this service. By combining technology and experience from AMRC with DMG MORI machinery, AML routinely offers its clients metal removal rates 2-3 times faster than could previously be achieved.

Evaluation of machine performance was a common demand at the AMRC for Dr Gareth Morgan “DMG MORI always came out high on the list for machine up-time, service, rigidity and repeatability and, without these characteristics, it would be impossible for us to achieve the results we do.” Currently, AML has six DMG MORI machines, one NT5400, two NT4300s, one NMV5000 and two NMV8000s. It also has Mitutoyo CMM, Factory Master MRP, NX CAD/CAM and Vericut. He continues, “We chose DMG MORI machines for their 5-axis capabilities as they give us maximum flexibility for the wide range of parts we produce. In addition, my experience with the machines has given us an insight into ways of maximising their capabilities by optimising factors such as workholding and cutting methods. Where necessary, we also have access directly to Japan through dedicated DMG MORI service personnel for more advanced technological questions.”

Specific techniques employed by AML include resonance measurement and adaptive probing. With resonance measurement, accelerometers are fitted to the cutter and, in some cases, the billet. Readings are then taken to establish the best cutting conditions and methods. Using this technology enables the company to maximise metal removal rates by taking much deeper cuts than would normally be possible, avoiding problems commonly found when cutting titanium such as burning the tool and chatter which can damage the material and lead to high scrap rates. Dr Gareth Morgan says, “Resonance technology was my field of study for my PhD, so we are well advanced in its use. For aerospace parts we are working with aggressive materials and we are frequently removing over 80% of them, so this is a very important technique for us. The stiffness and dynamic vibration characteristics of the DMG MORI machines play an important role in making it highly productive.”

For adaptive probing the company uses a sequence of measure and cut operations which, at each step, automatically feed information back to the machine control to adjust the next cut. “We rely on the repeatability of the DMG MORI tool changer and axes to make this work, enabling us to achieve tolerances on diameters of ±6µ, results that would normally require a grinding operation.”

The flexibility of the DMG MORI machines has enabled AML to finish parts in one operation, so that they are ready to go into stores without any further benching operations. On one particular component, AML were able to machine every feature, including a complex internal formed radius. Dr Gareth Morgan says, “Hand dressing of features such as this internal radius inevitably leads to higher scrap rates as, with the quality demands of the type of components we produce, surface damage is unacceptable. By producing every feature of a component on the DMG MORIs, we can achieve zero scrap.”

Nigel Lane, Chairman of AML says, “For Tier 1 aerospace suppliers, stability of supply is a major factor, so avoiding problems during manufacture is key to a good relationship. The technology and equipment we use is aimed at eliminating uncertainty and at the same time shortening lead times and reducing cost. We are already well recognised in the industry for our advanced capabilities. Our relationship with the AMRC and DMG MORI gives us access to extra resources both in machining capacity and know-how and we are currently developing plans for a 50% expansion in our manufacturing facility. The first stage is already underway with a new DMG MORI NMV8000 arriving within the next month, cementing our commitment to DMG MORI as our machine tool partner.”