The roll slant and rotation direction of rollers play an important role in the quality of spiral hole shapes, with the theory and practice of milling spiral holes. In the boring process, the boring tool rotating along the spiral groove direction, the roller rotates in the same direction as the boring tool, whatever the boring tool changes direction, the roller also needs to change direction accordingly.
The tilt angle is considered to be an important factor affecting the forming quality of spiral hole shape. The design direction of a spiral hole is the tilt direction of the roller. It is the longitudinal axis of a roller that determines the strength of tool force while its slope determines the roll slant direction of the roller. The roll slant angle is equal to the tilt angle of the roller.
When the milling spiral holes is in process, for the longitudinal axis direction of the roller to that of the boring tool, it has two kinds of structure: one is parallel structure, the other is hydraulic structure. According to their respective characteristics, each kind of structure can be applied to different operating situations.
The parallel structure is advantageous in the fact that its roll slant angle is exactly the same with the tilt angle. As a result, the roll can keep its tilt angle unchanged during the entire machining process, thus avoiding the problem of tool forces change during machining spiral holes.
The hydraulic structure, however, is flexible in adjusting the roll slant angle. With different pressure applied in the hydraulic chamber, the tilt angle of the roller can reach the desired effect. In addition, it is also very easy to reverse the tilt angle during the machining process. This permits the flexibility to shift the tool forces during machining so as to ensure excellent forming quality of spiral hole shape.
In summary, the roll slant and rotation direction of rollers have a very important influence on the forming quality of spiral hole shape. During the machining process, the parallel structure ensures that the tool forces remain constant, while the hydraulic structure increases the flexibility and accuracy of adjusting roll slant angle. These two structures combined together can form an ideal forming quality of spiral hole shape.
