The new type of medical titanium zirconium niobium alloy has the advantages of high specific strength, low elastic modulus, good biocompatibility and corrosion resistance. It is an ideal dental implant material to replace vanadium-containing titanium alloy commonly used at present. However, due to its high chemical activity, low thermal conductivity and elastic modulus, titanium-zirconium niobium alloy is a typical difficult material to process, and its adhesion property increases the difficulty of drilling.
The effects of drilling parameters (cutting speed and feed speed), drilling methods (peck drilling and traditional drilling) and cooling methods (dry cutting, pouring cooling, low temperature cold air, micro lubrication, low temperature spray cooling) on axial drilling force, vibration, drilling quality, chip morphology and tool wear were studied. The experimental reference and theoretical support are provided for the application of the new β-type biomedical titanium zirconium niobium alloy in small hole drilling. The main conclusions of this paper are as follows :(1) The dynamic characteristics of drilling force and vibration of the new β-Ti-zirconium niobium alloy decrease with the increase of cutting speed and gradually stabilize the axial force, and the axial force increases with the increase of feed speed. The axial force of traditional drilling method is slightly smaller. In the five different cooling methods, the axial force is minimum under the condition of minimal lubrication. With the increase of the number of drilling holes, the axial force under different cooling methods increased, among which, the axial force under dry cutting and low temperature cooling methods increased the fastest, while the drilling force under the other three cooling methods increased slowly.
The chip morphology of the new β-Ti-65Zr-20Nb alloy shows that the chip morphology of traditional drilling is mainly continuous long strip curly chip and closely overlapping continuous long strip chip, while the chip morphology of pecking drilling is mainly continuous short spiral conical chip and folded chip. The maximum chip length decreases with the increase of cutting speed. According to the chip morphology, with the increase of the feed rate, the spacing of sawtooth fringes on the free surface becomes smaller, the distortion increases, and the cracks on the edges and inside of the chips become less. There is little difference in chip morphology under different drilling methods.
