Aerospace research benefits from Huron five-axis technology

The Bedford-based Aircraft Research Association (ARA), was founded in 1952 as an independent research and development organisation by 14 member companies, of the Society British Aerospace Companies, including Blackburn & General Aircraft, A.V. Roe & Co., Rolls Royce, and Hawker Aircraft. Their remit, which remains the same to this day, is to provide specialist services to the aerospace industry; including high speed wind tunnel testing, computational fluid dynamics, and high precision wind tunnel model design and manufacture. With recent Government emphasis on the aerodynamic and aerospace industries, ARA has been able to utilise investment that further enhances its offering to global aerospace partners.

ARA’s customers include most of the world’s major civil aircraft and defence system manufacturers and, with one of the world’s leading transonic wind tunnels on site, it is an important strategic facility for the UK aerospace industry. This was recognised recently when the Government launched two new initiatives, the UK Aerodynamics Centre and the Aerospace Technology Institute, in which ARA plays a significant and active role. The result of these initiatives was ARA’s access to Government funding, which has been invested to upgrade its wind tunnel, computational and machining capacity. This also included the purchase of a Huron KX50M five-axis machining centre from Fortron UK.

The Design and Manufacturing department, at ARA, focusses on the production of one-off and low-volume scale models, and associated equipment, for use in its own transonic wind tunnel (maximum speed Mach 1.4); as well as low-speed, transonic, supersonic and hypersonic wind tunnels in Europe, America and Asia. ARA is also a supplier of models for the European Transonic Wind Tunnel (ETW) in Germany and the NASA National Transonic Facility (NTF) in America. These are two of the largest cryogenic wind tunnel facilities in the world. The accuracy of these models is paramount as any surface deviations can affect the wind tunnel test results. Therefore, surfaces have to be produced to 0.025 mm geometric tolerances, with no steps on the surfaces whatsoever. This requires a high level of machining skill, together with manual polishing and finishing.

With some highly complex models requiring up to 3 months of machining time alone, the Government grant enabled ARA to review its machining capacity, which up to then included a number of large machining centres, and some smaller five-axis machines. ARA identified the need for a large five-axis capability that would open up opportunities for larger model manufacture, and also improve quality and surface finish; due to fewer set ups being required. The machine chosen was a Huron KX50M, supplied by Fortron UK. The machine is part of the specialist five-axis, high speed, machine range from Strasbourg, France-based Huron, whose focus is on high technology industries such as the aerospace sector. Established over 100 years ago Huron has consistently developed innovative, high-technology, high-performance products.

Fortron supplied Huron KX50M

The Huron KMX50M is a portal-style machine with continuous five-axis movement, with the rotational B and C axes contained within the milling head, and enhanced with linear axis travels of 2000 mm, 1700 mm and 800 mm in X, Y and Z, respectively.

“The Huron KX 50 meets our requirements completely and we are using its high speed machining capability to improve surface quality (or reduce cycle times), which in turn is reducing the amount of manual finishing required,”

says Martin Hammond, ARA’s Machining Strategy Leader.

“One of our major criteria was reliability, as due to challenging manufacturing timescales we need to be confident that the machine will perform as expected, and to the accuracy levels that we need, In this respect the Huron has not let us down.”

The Huron KX series of machines all feature +/- 95 degree movement in the B axis and +/- 190 degrees in the C axis and the KX50M, at ARA, benefits from a 75 KW/20,000 revs/min HSK 63A spindle, with control being provided by a Heidenhain iTNC 530 contouring control. The combination of machine build quality, and control system, results in a highly accurate machine, with repeatability of 0.004 mm in the linear axes, and 5 seconds in the rotational axes. To maximise the potential of the machine, especially on the cryogenic models that ARA produces, Huron and Fortron UK worked closely with ARA after installation to further develop the high speed machining strategies being used.

“Having this Huron machine means we now have the capability to manufacture larger wind tunnel models, than we could on our existing equipment,”

says Nigel Corby, ARA’s Business Development Executive.

“The performance of the machine also makes us more competitive on the world stage, where we have four, or five, main competitors for the research work that we undertake; and, while our core capability is in the design and development of aerospace related wind tunnel models, the addition of the Huron KX50M has also opened up opportunities to accept work from customers, who have a requirement for precision manufacturing of high value, highly complex components, for any industry application.”