Abstract: The scale thorn generation regularity and its inhibitory measures were researched during the turning processes of titanium alloy. The main factors of scale thorn formation were analyzed. The break law of scale thorns was analyzed by moment method. Then, a mathematical model was established among cutting parameters, tool geometric parameters with moments of tool nose. By solving through MATLAB, it is found that the cutting speed has the least influences on the moments of tool nose, and the sizes of the moments of tool nose are determined by cutting depth , feed rate, corner radius and tool cutting edge angle. In order to verify the trend of the model, the intermittent experiments of turning typical titanium alloy TC17 were carried out. The sample data of scale thorns were collected with constant cutting speed, different cutting depths, different feed rates, different corner radius and different cutting edge angles. Furthermore, the curve of scale thorn break regularity was gained. The experimental results show that, with the cutting parameters less than the critical cutting depth and larger than the critical feed rate, the experimental results are consistent with the overall trend of mathematical model, which proves the rationality of the model. This study may provide data support for high quality machining of titanium alloys in terms of technology and tool selection.

Key words: titanium alloy, cutting, scale thorn, cemented carbide tool, smoothness

摘要： 为研究钛合金车削过程中鳞刺生成规律及有效抑制措施，分析了影响鳞刺生成的主要因素，采用弯矩法解析了鳞刺折断规律，进而建立了切削参数、刀具几何参数与刀尖弯矩的数学描述模型；通过MATLAB对模型进行求解，获知切削速度对刀尖弯矩的影响最小，而切削深度、进给量、刀尖圆弧以及刀具主偏角4个因素决定了刀尖弯矩的大小。为验证描述模型的正确性，进行了典型钛合金TC17外圆周断续切削实验，采集在恒定切削速度、不同切削深度、不同进给量、不同主偏角及不同刀尖圆弧条件下的鳞刺样本数据，并获得鳞刺折断规律曲线。实验结果表明：在小于临界切削深度和大于临界进给量条件下，实验结果与数学描述模型整体趋势一致，证明了数学描述模型的正确性。研究结果可为钛合金的高品质加工提供工艺技术及刀具优选方面的数据支撑。

关键词: 钛合金, 切削, 鳞刺, 硬质合金刀具, 表面粗糙度