Serkan Erten, business unit director of Alp Aviation’s Engine Business Unit reveals how the investment in a M40 MILLTURN - supplied by WFL Millturn Technologies - enables the company to become a centre of excellence for civil aircraft engine manufacture.

Alp Aviation is a joint venture with Sikorsky Aircraft, a Lockheed Martin company, established in 1998. The company’s core competence is its extensive experience in machining and processing titanium, super alloys, aluminium, steel, stainless steel, magnesium and copper alloys. Alp Aviation has four facilities in Eskisehir with a total production area of 50,000m².

Q: What is Alp Aviation’s core competence and which business fields are you operating in?

We mainly sell to North America and Canada, but we also deliver to Europe too. The export ratio is about 98%, whereas 90% are being delivered to North America. For manufacturing we only have the facility in Eskisehir, where five business units are located. One of Alp’s business units is the Aerostructure business unit.

The second business unit is the Engine business unit for which I’m responsible. We are manufacturing engine dynamic components, for Pratt and Whitney and Honeywell. At military level, we’re working on the F-135 Engine, and at commercial level, we are working on the Geared Turbofan (GTF) engines. Honeywell is an important customer for engine components too. We began producing tie shafts for their commercial engines.

For that purpose, we invested in a M40 MILLTURN with 3,000mm centre distance. The third business unit is the Rotary Wing business unit. Their main responsibility is to provide dynamic helicopter components, gears, gearboxes and other dynamic components for helicopters. The fourth business unit is Special Processes. Here we have a huge capability in-house and can do the chemical and mechanical processes ourselves. There is also a fifth business unit for landing gear. We are working together with Collins Aerospace and Heroux Devtek on the F-35 programme and on other commercial programmes for Boeing and Airbus.

Q: What is the main reason for investing in a MILLTURN complete machining centre?

At present, we have over 250 machine tools and we are producing a wide range of parts for the aerospace industry. 5-axis milling and MILLTURN equipment is mainly being used for producing those components. On the new M40 MILLTURN we only manufacture shafts. The main purpose of the investment was to be at the centre of excellence in shaft production for engine producers. With the WFL MILLTURN, we have become a tie shaft producer for our customers. Tie shafts are a critical component of engines and serve as a connection between the turbine and the compressor.

The length of the tie shafts we manufacture range from 1,000mm to 2,000mm. The main materials used to produce the tie shafts are Inconel and maraging steel. We have lots of experience with Inconel production, as we have already started to produce engine components made of titanium or Inconel in 2008. For that reason, we have enough experience with these materials. With regards to the shafts we continue to work with Inconel material and high strength steel.

Q: Can you tell us about the main requirements for investing in a new complete machining centre?

To be able to produce dynamic engine components, we need productive and process-reliable high-tech machines and outstanding technological performance. Nickel alloys are commonly used during engine component production. These special nickel alloys are highly heat resistant. These materials are extremely rigid, difficult to machine and a high level of technological expertise is required to meet the high quality standards in the industry.

Q: Which machines or processes were replaced upon the purchase of the M40 MILLTURN?

The installation of the new MILLTURN enabled us to produce larger shafts for the first time. Up to this point of time we only manufactured smaller shafts starting from 250-500mm length on smaller machines. When we received drawings for bigger and longer shafts we established contact with WFL, because we knew that they have a very good reputation in the aerospace industry. We are now producing about 200 shafts per year.

Q: What are the technological possibilities with the M40 MILLTURN?

With the implementation of the M40 MILLTURN we achieved perfect machining performance, high surface quality, high static, and dynamic rigidity, as well as reliable and repeatable accuracy. In-process measurement is an important technology to achieve the tight tolerances. We prefer multitasking machines, as there is no need to move parts from one machine to another one. Timesaving was also a crucial factor for buying the machine.

Q: What are the main advantages of complete machining?

By doing complete machining on one single machine tool, processing time could be reduced by 30% with an increase in flexibility of 60%. Our customers need to rely on our performance, and it is important to work most efficiently to achieve low lead-times.

Q: Tell me more about the manufacturing of the tie shafts on the MILLTURN?

The production of one shaft, starting with the procurement of the materials up to the finishing processes, lasts around six weeks. This type of shaft requires chemical as well as mechanical processes, such as heat treatment, shot peening, chrome plating, silver plating, grinding or balancing. The fact that the entire process can be done in-house is the main strength of Alp Aviation in order to satisfy our customer’s needs.

Q: What are the future strategies of Alp Aviation?

We aim to be at the centre of excellence regarding design and manufacturing of engines, as well as fixed wing and rotary wing dynamic components. Furthermore, we intend to be at the centre of excellence for the production of shafts. Alp Aviation has been approved as a Research and Development Centre by the Turkish Government. This is a major step for gaining even more significant roles in national and international programmes as a design and engineering partner. We will be able to be a global subsystem supplier in design and production for our customers.

Q: What measures are you taking with regards to Industry 4.0?

We have been following all the technological developments. We established a flexible manufacturing system with four machine tools and a centralised tool change system two years ago, and thanks to this innovative solution, productivity increased by 30%. Our aim is to reduce labour hours and increase the technological improvements. For that reason, all our investments are the basis for this approach. When we made the decision to invest in a MILLTURN, we also discussed this topic and the future development. As soon as the economic situation improves and requests increase, we will probably invest in further machines as well in automation.

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