# Cutters

Cutter is a unique and relatively complex in design of a gear cutting tool.

Cutter in its form resembles the usual gear. Cutter consists of an infinite number of elementary thin-corrected the wheel, so as the same points of the cutting teeth blades for different cross sections are closer to the center of the shaping cutter. In turn, the front corners are provided by a sharpening of its front end by an inner conical surface.

The shaping cutter has a rear and front corners on the tops and the sides of the profile of its teeth. These angles should be races to be dealt with in three sections.

the Second clearance angle is calculated in when designing the tool.

Rear angle in the normal section to the side profile of the tooth indicates the actual gap between the rear surface at a given point blade tooth and the cutting plane.

the Front corners, as well as the rear, measured in the above three planes. It is established that the increase in external front and rear a substantial increase in the deviations of the involute profile of the teeth cut into the wheel that can be seen from the formula for determining the angle or profile of Reiki

Available shaping cutter clearance angles cause a number of peculiar features in the form of his teeth.

1. As mentioned above, the sides of the teeth are made on the involute. So as of regrinding the shape of the blades the tooth is not changed, the sides are ground off them-not smiling on the cone, like bevel gears, and run as involute helical surfaces, which are formed by screw motion of a straight line along the guide cylinder with a diameter base circle. Due to this, in any cross section of the shaping cutter. perpendicular to its OSP, are the same (identical) evolvente; their shape is determined only by the diameter of the base circle. On one side of the screw tooth surface is done right, and another left, causing the sides of the tooth are created rear corners.

2. From the point of view of the geometric theory of meshing involute gears cutters can be represented as a sum of infinite number of elementary wheels with positive, negative, and zero offsets of the original contour of the rail, with an infinitely small width of a rim. As perekachivanija shaping cutter to the work during cutting and engagement with a cut wheel enters one of these infinitely thin gears.

In the source section of the shift rails is equal to zero, and the size and profile of the teeth are determined by the relevant parameters of the cut wheel. In other words, the size of the teeth of the shaping cutter in the original section are purely theoretical, and computational. Almost all sizes are measured in the front plane. Dividing the estimated diameter of the shaping cutter D, remains constant for all sections. Therefore, in the cross section of the structural elements shaping cutter will have the dimensions differ from the dimensions in the source section.

changing these sizes affects the amount of displacement of the source section and the rear corner.

the Offset of the original contour of the rail, measured in the radial direction, in the theory of korrigirovanija involute gearing is usually expressed using the displacement coefficient and in the share module.

the Increase and provides the following benefits:

1) improve surface finish cut tooth profile accuracy, resulting in less noise and smoother engagement;

2) reducing the risk of cutting the profile with a small number of teeth.

on the other hand, the maximum increase in distance and is limited to:

1) by reducing the thickness of the tooth on the top. The more and the thinner the tooth tip, and this naturally leads to a reduction in resistance of the shaping cutter;

2) the more a, the more the plot nevolently profile obtained at the base of the cut tooth. This plot is called the transition curve. In case of significant dimensions of the transition quality of the cut gear wheels.

as a result of regrinding dalbekov on the front surface of the thickness of its tooth with vremenem decreases, changes accordingly the value of a, which leads to the danger of pruning this fact causes the cut wheel with a small number of teeth.

This ratio is selected on the tables or on a special chart, based on the conditions valid cutting edges and lack of pruning. Currently, apart from the usual spur of the disk or Cup, sleeve and tail dalbekov, are also widely used and special combined helical cutters.

Shaper used to get wheels with oblique teeth, are of two types. They differ in the shape grinding of the front surface, and a shaping cutter the accepted standard module in normal and the other in the middle sections. It should also be noted that the disc cutters used on the V-wheels can only work in pairs: one right, the other left-hand inclination of the teeth.

To facilitate the work dalbekov that when you receive the gears, hitting the body of the workpiece, quickly become dull and lose their precision, apply the combined cutters. Such cutters have teeth with a reduced thickness, which is made by rough cutting and the teeth normal thickness, carrying out a finishing cutting. In addition, this cutter has the installation site without teeth, which allows the installation and removal of the workpiece without removal of the spindle of the machine and shortens the path required for cutting shaping cutter. This fact causes during the first rotation of the blank is rough, and the second turnover—a fine chiselling. But despite a significant increase in performance, these cutters are used for cutting wheels with only a certain number of teeth.