The initial path of crack pro-pogation is related with a rake angle of the cutting blade.

裂纹扩展的初期路径与刀具的前角有关。

Rake Angle. It is the Angle between the face of the tool called the rake face and the normal to the machining direction.

它是被称为前倾面的刀具面与垂直机加工方向的夹角。

The effect of tool rake angle on the geometric shapes of the chip, cutting force and cutting temperature is investigated.

分析了刀具前角对切屑几何形状、切削力和切削温度的影响。

The results show that the effects on surface roughness are feed speed, depth of cutting , tool rake angle and parts hardness in turn.

结果表明：工件进给速度对表面粗糙度的影响最大，切削深度和刀具前角次之，工件硬度影响最小。

This paper also discusses bit parameter design to improve the economy of PDC bits, such as negative rake Angle and side rotation Angle.

本文还介绍了为提高复合片钻头经济指标的钻头参数设计问题，如负前角，侧旋角等。