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

在连续进给条件下用麻花钻钻深孔时，为了排屑，必须使屑为连续型，并能通过钻槽移动，因为分段式屑容易堵塞钻槽。自由生成的切屑为锥形螺旋型。因此，有必要将钻槽和被钻孔变形为直径较小或长节距的螺旋型切屑，其节距等于凹槽节距。由于常规钻头的主切削刃较宽，且几乎与半径矢量相对应，因此采用半正交切削，自由生成的切屑为小节距的锥形螺旋型切屑。很难将其变形为上述芯片。一种新型麻花钻每边都有两个刃口。每个切割刃独立切割工作材料。每个尖端产生的芯片并不完美统一。由内切削刃产生的芯片附着在由外切削刃产生的芯片上，外切削刃是主芯片。这是控制切屑变形和排屑的基础。由于外切削刃有较大的斜角，这种锥形螺旋型切屑具有较长的节距，在深孔钻削中由凹槽和钻孔控制为长节距型。

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.