Evaluation of the machinability of Ti–Sn alloys

Abstract

The machinability of a series of binary Ti–Sn alloys with Sn contents ranging from 1 to 30 mass% was investigated, using commercially pure titanium (c.p. Ti) as a control. The specimens were slotted using an electric dental handpiece and end mills. Machinability was evaluated by the cutting length, which traveled by the end mill from one edge of the specimen to the other edge. For each metal specimen, a permitted cutting time of 3 min was used to determine its average cut length. The experimental results indicated that alloying with Sn significantly improved the machinability of c.p. Ti in terms of cutting length under the present cutting conditions. The Ti–Sn alloys with a higher Sn concentration could be cut more readily. At 120 m/min, the lengths for Ti–20Sn were about 1.3 and 1.4 times higher than that of c.p. Ti at 200 and 300 gf, respectively. Additionally, the lengths for Ti–30Sn were about 1.7 and 1.8 times higher than that of c.p. Ti at 200 and 300 gf, respectively. For Ti–20Sn and Ti–30Sn, there was no adhesion of metal chips observed in the appearance of the cut surfaces at 120 m/min. Furthermore, they had the lowest surface roughness (Ra) values at 120 m/min. Our research suggests that the Ti–Sn alloys with Sn contents of 20 or 30 mass% developed here are viable candidates for machining at the rotation speed of 120 m/min by the CAD/CAM method.