Micromilling of Ti-6Al-4V alloy for high-aspect-ratio thin walls and dimensional error compensation based on an online compensation system

The requirements of fabrication quality of high-aspect-ratio (HAR) thin walls made of titanium alloy are increasing in various engineering fields. However, there is a lack of studies investigating the fabrication of HAR thin walls with high-dimensional accuracy. This paper studies micromilling characteristics of titanium alloy for fabricating HAR thin walls. First, micromilling experiments using straight edge polycrystalline diamond (PCD) end mills with different rake angles are conducted. Comparisons of the effects of tool shape on cutting force, cutting temperature, thin wall dimension error, tool wear, and surface morphology are analyzed systematically, and the optimal cutting edge shape has been identified. Second, a deformation prediction model for micromilling of titanium alloy is established and calibrated. The model can be applied to online compensation of thin wall deformations. Then, dimensional error compensation experiments on HAR thin walls are carried out. The result shows that the proposed prediction model is effective. A thin wall with an aspect ratio of 10:1 and a thickness of 60 µm is successfully fabricated with high-dimensional accuracy. The relative dimensional error is reduced from 16.5 % to 3.9 %. It also provides a method for guiding the thin wall machining of other difficult-to-machine materials.