The advantages of the five-axis flank milling of (developable) ruled surfaces include that (1) the machined surfaces could be very accurate and smooth and (2) the machining efficiency is high. Currently, spiral bevel gears are machined on the machine tools specially used for gear manufacturing. The disadvantages are that the cost is high for small batch, prototype, or repair. If a small group of spiral bevel gears are needed, the current methods are not valid. Thus, it is expected to machine the gears on five-axis computer numerical control (CNC) milling centers. Unfortunately, when tooth surfaces are designed based on the conventional gear manufacturing methods, they cannot be accurately machined in five-axis flank milling. This work is to develop the new technique for the five-axis flank milling of spiral bevel gears. First, a new method of designing the tooth surface of spiral bevel gears with ruled surface is proposed. Second, the cutter locations and orientations are calculated for five-axis flank milling the tooth surfaces. Third, the actual tooth surfaces are accurately represented with the cutter envelope surface in five-axis flank milling. It is confirmed that the difference of the actual tooth surface and the designed tooth surface is within the tolerance. Then, a pinion is generated to mesh with the gear, and the tooth contact analysis (TCA) is conducted. The good result demonstrates that the proposed method is valid, thus it can be used in industry.

As an important feature of cutting tools, flutes determine rake faces of their cutting edges, their rigidity, chip breaking, and chip space. In industry, flutes are often ground with standard wheels of simple shape (e.g., 1A1 or 1V1 wheels), resulting in flutes without much variation. To make flutes of more complex shape, standard wheels of complex shape (e.g., 1B1, 1E1, 1F1, and 4Y1 wheels), compared to the current ones, should be used. Unfortunately, current commercial software cannot calculate the locations and orientations of these wheels; this is why they are not used to machine flutes. Moreover, grinding wheels are gradually worn out in use, and the flutes lose accuracy accordingly. Therefore, locations and orientations of the worn wheels should be recalculated or compensated in machining; however, no such technique is currently available. To address this challenge, a generic and efficient approach to determining the locations and orientations of complex standard and worn wheels for cutter flute grinding is proposed in this work. First, a parametric equation of the generic wheel surface and its kinematic equation in five-axis flute grinding are rendered. Second, virtual grinding curves are proposed and defined to directly represent the relationships between wheel location and orientation and the flute profile in a geometric way. Then, the characteristics of the virtual grinding curves are investigated and formulated, and a new model of the generic wheel location and orientation is established. Compared to the existing comparative model, this model significantly increases solution liability and computation efficiency. Finally, three practical cases are studied and discussed to validate this approach. This approach can be used to make flutes of more complex shape and can increase flute accuracy by compensating the locations and orientations of worn wheels in machining.

Plunge milling is an effective roughing operation, especially in pockets roughing, because it can efficiently remove a large amount of stock material without high manufac turing costs. However, plunge milling o f complex pockets with islands, whose boundaries could be designed with free-form curves, is quite challenging for multiple plungers have to be used including small plungers to cut necks between islands and their plungers paths are expected to have fewer times of plunging and shorter travel to achieve efficient machining. Unfortunately, little research on this topic was carried out in the past, and the challenge has not been addressed yet. In this research, a new approach is proposed to generate plunger paths for efficient plunge milling of the complex pockets. Its main features include (1) packing plunger circles at a minimum number of locations inside the pocket for fewer times of plunging, (2) placing plunger circles to cover the areas enclosed by the afore-packed circles to clear out the interior pocket material, and (3) planning the shortest paths to connect plunger locations for less traveling time. The advantages of this new approach over the overlapped circles filling (OCfill) and the Catia methods are dem onstrated with two examples, and it can be directly used for pocket plunge milling in industry.