Swiss company Starrag has solved a seemingly impossible task: Brazilian aircraft manufacturer Embraer / Eleb was looking for a machining centre to machine main landing gear components in a confined space using a highly efficient and reliable process. As a solution, Starrag built the Droop+Rein FOGS D40 Twin high-gantry machine at its site in Bielefeld. This machine uses two spindles in order to minimise space requirements and significantly reduce the level of investment in comparison to a solution using two machines.
Embraer / Eleb is the world‘s fourth largest aircraft manufacturer. The excellent reputation Starrag enjoys as a machinery specialist for the aerospace industry was the main reason it received the order: Thanks to its Droop+Rein machines, Starrag has a global market share of over 80 % inthe production of landing gear components. Based in São José dos Campos near São Paulo, the aircraft manufacturer will use a Droop+Rein FOGS D40 Twin from summer 2018 to machine die-forged parts made from low-alloy, heat-treatable steels with the designation 300 M in a close-contour process. The main structural components, such as the landing gear housing and piston rods with integrated axles for Embraer / Eleb‘s main landing gear, will then be produced in several production steps.
This uses a fork-type milling head with cartridges for replaceable spindles, which enables simultaneous five-axis machining. Embraer / Eleb can choose to use either the mechanical 40-kW gear milling spindle with a maximum torque of 1,100 Nm and 5,000 rpm or the rapid 20-kW motor milling spindle with 48 Nm and 18,000 rpm. Ulrich Vollmer, Head of Project Engineering in Bielefeld: ”We have also developed an additional angle head spindle for drilling especially for this application.“
The high-feed cutting is handled by the mechanical spindle at a rate of 4 to 5 m/min and the smoothing is per formed by the motor milling spindle at a rate of 10 to 12 m/min. ”This is also the general feature of the Droop+Rein FOGS D40, which is a multi-functional machine for highly dynamic roughing and smoothing“, says Ulrich Wiehagen, Plant Director at Starrag Technology GmbH in Bielefeld. The main focus is on high-precision, rapid smoothing. The Twin comes into play where two high-gantry machines would otherwise be necessary.
Starrag reduces the unproductive time required for tasks like handling or setup using a robot that moves in a linear direction. This robot supplies the Twin with tools through a window from a rack-type magazine containing 320 pockets. The machine has two working areas to allow setup to be performed during the machining time: As new workpieces are be set up in one working area, machining can be performed in the other.
The solution is a prime example of how Starrag lives up to its claim Engineering precisely what you value. Why did Embraer/Eleb receive exactly what the company needs? Wiehagen: ”Compared to the otherwise standard solution with two machines, the Droop+Rein FOGS D40 Twin reduces the space requirements by 40 % and the price by approximately 30 %, whilst providing around double the output. The Twin also has a very positive impact in terms of personnel costs, as only one operator is required rather than two.“
Switzerland 
