DEFORM- AND EXHAUST-CONTROLL OF CHIP IN DRILLING WITH A NEW TYPE TWIST DRILL

在用麻花钻连续进给的深孔加工中，为了排屑，切屑必须是连续型的，并且能够通过钻槽移动，因为节段式切屑容易堵塞钻槽。自由生成的切屑为圆锥螺旋型。由于常规钻头的主切削刃较宽且几乎与半径向量相对应，因此需要对其进行半正交切割，生成的自由生成的切屑为圆锥形小螺距螺旋型切屑。很难将其变形为上述切屑。一种新型麻花钻两边各有两个刃口。每个刃口都独立切割工作材料。每个刀刃产生的芯片并不是完全统一的。由内切削刃产生的切屑附着到由外切削刃产生的切屑上，该切屑是主切屑。这是实现芯片变形和排气控制的基础。由于外切刃有较大的倾角，这种锥形螺旋型切屑节距较长，在深孔钻削时，沟槽和钻孔将其控制为大节距类型。

In order to exhaust chip in deep hole drilling with a twist drill under continuous feed, it is necessary that the chip is a continuous type and can move through the drill flute, because the segment type chip tends to clog the drill flutes. The freely generated chip is the conical helix type. Therefore, it is necessary that the drill flute and the drilled hole deform it to the smaller diameter or to the long pitch helix type chip, whose pitch is equal to the flute pitch.As the main cutting edge of a conventional drill is wide and almost corresponds to the radius vector, the semi-orthogonal cutting is carried out, and the freely generated chip is a conical helix type one with small pitch. It is difficult to deform it to the above mentioned chips.A new type twist drill has two cutting edges on each side. Each cutting edge cuts work material independently. The chips generated by each cutting edge are not perfectly unified. The chip by the inside cutting edge is attached to the chip generated by the outside cutting edge which is main chip. This is the basis to the deform- and exhaust-controll of chip. As the outside cutting edge has a large oblique angle, this conical helix type chip has longer pitch, and the flute and the drilled hole controll it to the long pitch type in deep hole drilling.