Procedure for selecting a standard disk modular cutter for manufacturing a helical gear in a repair shop

Gear milling using universal horizontal milling machines is applied in repair shops to manufacture module gear disk milling cutters. In the case of spur gears production, depending on the number of their teeth, cutters of the number specified in OST2 I 41-14-87 (from the standard set of cutters) are used. In the case of helical gears milling, cutters with a special profile are required. In this case, profile calculation is carried out in two stages. At the first stage, direct problem solution - calculation of the specified profile is implemented using an analytical method or modern CAD programs. At the second stage, verification problem - calculation of` the gear wheel `profile that will be formed by the designed cutter is executed. Since cutter profile belongs to the class of convex-concave profiles, it is difficult to solve this problem using modern CAD programs. One of the ways to solve this problem is traditional analytical approach, and its implementation in practice is easily feasible for cutters with a profile approximated by straight line segments. This approach is described in the presented study. It is showed that when solving a direct problem using the Solidworks program, the resulting wheel profile almost completely coincides with its original profile. The second stage of this study was to examine the possibility of using standard cutters with numbers different from those required by the specified standard. The practical expediency of this approach lies in the use of inexpensive standard cutters, designed for the cases of spur gear machining described in the specified standard, in relation to other cases of helical gear milling. The calculation example performed for the case of the wheel with 34 teeth, module of 4.5 mm, and a tooth inclination angle of 29 degrees showed that the use of the cutter with a number 8 gives a maximum deviation of the above-mentioned profiles within 117 mkm at the tooth tip. Grinding a standard milling cutter to the specified value in repair shop usually does not cause any difficulties, which will allow obtaining a wheel of the required accuracy with tooth profile that practically corresponds to the drawing or a workpiece for finishing operation.