At the end of the day, people do business with people and meeting face to face at networking events is often the best route towards long and fruitful partnerships. This proved to be the case with tooling specialist MMC Hardmetal (a group company of the Mitsubishi Materials Corporation) and Advanced Manufacturing (Sheffield) Ltd (AML) who met at the Global Manufacturing Festival held at the University of Sheffield AMRC during April this year. Now the two companies are collaborating on some pretty high flying aerospace projects as Dave Tudor reports.
AML was set-up around four years ago by Sheffield University graduate Dr Gareth Morgan, initially as a splinter consultancy company to support the AMRC in many of its pioneering aerospace projects. Dr Morgan has devoted much of his working life studying and researching the science behind cutting metals efficiently and productively, with the elimination of vibration and chatter – major contributing factors towards poor surface finish, component accuracy, spindle and tool life, long cycle times and poor productivity – high on the priority list.
The appliance of science to machining tasks is what AML is all about, but behind the science are significant practical benefits. Back in 2009, Dr Morgan made the claim that through machining dynamics analysis and advanced process optimisation techniques, AML could reduce cycle times by a minimum of 30% whilst still maintaining the required levels of accuracy, productivity and quality.
That statistic is still very much the objective today. AML's raison d'etre is to take a part, however complex and establish the most productive and economical way of manufacturing it – from prototype through to full batch production. It achieves this via a number of scientific methods centred around machine dynamics optimisation such as Tap Test Analysis and Adaptive Probing.
AML today is an independent, standalone company in its own right. It is still based close to the AMRC in Rotherham, but now employs around 20 members of staff with a turnover of £1.5 million. Importantly, whilst AML still offers a consultancy, development and prototyping service, it has now evolved into a full blown manufacturing facility. This effectively means that the company, having produced fully optimised prototypes, one-offs and small batches, now has the capacity and capability to go into full production if required.
“When we first began we had to use the AMRC's machine tools for our development work but now we have our own dedicated 10,000ft² production cell that houses four Mori Seiki machines (two NMV series VMCs and two NT turning centres) and a CMM,” Dr Morgan explains. “We run a two shift system and are an approved supplier to major OEMs within the aero engine, aerostructure and energy markets. We're also a Tier Two member of the AMRC with Boeing.”
The partnership between AML and Mitsubishi began at the Global Manufacturing Festival held at the AMRC in April. Mitsubishi was showcasing its brand new range of iMX exchangeable head end mills at the event when Adam Brown, an aerostructure specialist at the AMRC recognised the potential for two projects AML was currently working on.
Mitsubishi is promoting iMX tooling as a ‘world first' that combines the advantages of both solid carbide and indexable end mills. It achieves this via a two-part system – a carbide interchangeable head and a carbide holder.
Effectively, the head screws securely onto the tool body – so securely in fact that Mitsubishi claims that the rigidity is close to that of a solid type end mill. This is made possible because the taper and end clamping faces of the head and the holder are both solid carbide – only the threaded part is composed of steel.
Mark Timbrell of Mitsubishi's European Marketing Department believes that the benefits of this clamping method when compared to the usual steel to carbide method are greater efficiency from increased cutting parameters, improved accuracy and the all important factor of reliability.
“Other tools with a carbide head to a carbide clamping section are usually constructed with a part carbide section brazed to a steel shank,” he says. “This method has inherent weaknesses at the joint when compared to the solid carbide shank used on the iMX range.”
It's a miracle
The iMX exchangeable series of end mills has obvious advantages for reducing inventory levels and tool change times, but they are also capable of high performance over a wide variety of applications – from the machining of titanium and heat resistant alloys such as Inconel, to the high performance milling of stainless steels, carbon and alloy steels and hardened steels. Each head type has irregular helix flutes for vibration control and the four flute corner radius type incorporates through coolant holes.
The wide variety of applications is courtesy not only via the rigid clamping system, but also through the new Smart Miracle coated carbide grade EP7020. The super fine, super hard carbide substrate has a newly developed (Al, Cr)N coating that can deliver substantially better wear resistance. iMX actually forms part of Mitsubishi's new Miracle Sigma range of tooling launched at the recent EMO show in Hannover. The range is designed for optimum performance on difficult to cut and heat resistant materials.
iMX heads are supplied in a range of different geometries: four flute corner radius (with or without through coolant) in 10-25mm diameters with irregular helix for vibration control; six, 10 and 12 flute in diameters from 10-25mm for finishing – also with irregular helix; and four and six flute ball nose, also in 10-25mm diameters with irregular helix. iMX carbide shanks are also provided in diameters from 10-25mm. Future additions to the series will include variant specifically designed for the machining of aluminium and a high feed rate version.
“As tool diameters increase, solid carbide tools can get very expensive,” explains Adrian Barnacle, Mitsubishi's advanced materials applications manager. “The fact that the iMX range is interchangeable gives customers access to Mitsubishi's renowned cutting technology, coatings and geometry, but without having to purchase a new shank every time.”
Aside from the economic benefits of the interchangeable heads, an aspect that really appealed to Dr Morgan and his team at AML was the fact that Mitsubishi took on full responsibility and ownership of providing a regrinding capability for the iMX tools. “This was actually something that differentiated them from many of the other tooling suppliers,” he reveals. “To maintain continuity in production, we need a rapid, reliable regrinding service and they arranged this through Peterborough-based Marlor Tooling. It was very reassuring to us to have this service – and with a company that is actually recommended and trained by the manufacturer.”
On the double
The two projects where the AML/Mitsubishi partnership has come to fruition are with the machining of a deep pocketed, high value titanium airframe component for the aircraft industry and blade machining for a UK aero engine supplier. For AML, both projects are in early stages of development but the reality is that once production ramps up, the company will be top of the shortlist.
“Unquestionably, the use of solid carbide tools for machining the deep pockets would have been astronomically expensive,” Dr Morgan explains. “The iMX tools provided a much more cost-effective solution and their advanced geometry means we can push them hard in terms of feeds and speeds and still get excellent surface finishes. We can definitely see the potential for iMX on other projects.”
The second collaborative project for the two companies – again taking advantage of iMX tooling is no less innovative. A UK aero engine provider has developed a new design for an aerofoil component. From a machining viewpoint (this part is 100% machined all over) the titanium part comprises a number of complex contours and undulating profiles.
“We were awarded the contract to produce these parts for an engine development test programme,” Dr Morgan reveals. “There will be 22 engines built in the UK for testing purposes and each engine will be progressively and more rigorously tested until the final incarnation which will be used in actual flight.”
So with a wealth of tooling companies to choose from, why did AML choose MMC? I leave the final word to Arwen May, QMS manager at AML who is also responsible for purchasing: “Working with Mitsubishi has been a breath of fresh air,” she says. “When I pick up the phone with a query I get to speak to a real human being who is keen to help. They're supportive, responsive and if I have to leave a message they'll always call back promptly. Our engineers enjoy a similar experience when talking on a technical level with their counterparts at MMC.”