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Geared Turbofan

Gears in aerospace

Aircraft engines are changing to adapt to the tighter environmental regulations. One of the resultant developments has been the geared turbofan. Currently, the most famous ones are the PW1000G from Pratt & Whittney and the Ultrafan from Rolls Royce.
These two engines have a planetary reduction gearbox between the fan and the low-pressure shaft (2). This allows them to run at a higher rotational speed, which helps reduce the number of stages in the low-pressure turbine and low-pressure compressor.
In manufacturing terms this gearbox brings gear production to the forefront of engine production.
Geared Turbofan NT

Gears production in the past

Gear production has traditionally been undertaken on specially made machines, which were adjusted by highly skilled operators with lots of experience. But this traditional means of production is no longer sustainable in today’s production environments. The challenge is how to bring gears production up to date.

The part we will see was programmed and produced in just one morning. Let's see how this is possible
Gears production in the past

Sandvik's Invomill technology on D500 - Leading the technology wave

Makino's application engineers studied the components and solutions on the market and found the best fit between our technology and CAM/tooling in Sandvik’s Invomill technology. So how does it work?
  • Enter the gear data and create the 3D model of the gear in the Invomill software
  • Create the various machining operations (roughing, finishing, etc.)
  • Check every operation with the 3D machining simulation
  • Post the NC for D500
  • Check the collision situation with the 3D simulation
Sandvik's Invomill technology on D500 - Leading the technology wave

What are the results?

We machined the gear using Sandvik's Invomill process. The gear data were as follows:
  • Module: 3.5
  • Teeth: 36
  • Pressure angle: 20°
  • Helix angle: 19.3°
  • Helix direction: right hand
  • Face width: 52 mm
By using the Invomil technology on the Makino D500 5-axis vertical machining centre, we were able to achieve:
  • Gear quality profile:  IT3-5
  • Gear quality flank:    IT3-6

And don’t forget: this test was done in one morning together with Sandvik, using just the standard Invomill tools.
What are the results?