Titanium brackets in planes are used throughout the aircraft. They are normally key components that form the joints between different types of materials or reinforce areas where only CFRP materials are used. They can be seen from the door components to the wings and central body.
The component we are talking about is a demonstrator made by Makino. It has all the main features that can normally be seen in brackets, e.g. precisely related bores, deep pockets, high material removal needed, long tools, etc.
Clamping process
Of the huge variety of processes possible (mainly dependent on the geometry of the bracket) we selected a simple bracket with tight tolerances between the bores.
In order to maximise the tolerances we tried to cut all features from one side. To do this, in a first operation we face-milled the back and prepared some drilled holes.
In a second operation, clamped from the drilled holes, we cut the complete part.
Machining process
For this bracket we wanted to push hard on the performance of the 14,000 rpm machine with 302 Nm torque so we tried to use tools that defy the spindle, e.g.:
Porcupine cutter - diameter 50 with 5 flutes - 0.12 mm/tooth on roughing
Porcupine cutter - diameter 32 with 3 flutes - 0.1 mm/tooth to produce the centre slot by full slotting
End mill - diameter 20 with 5 flutes - finishing in one shot all the wall of the slot
