Selection, grinding and installation of trapezoidal thread turning tool Angle

1. Shape of turning tool

Trapezoidal turning tool is a simple forming turning tool, its thread tooth Angle is 30° (29° in British system), trapezoidal thread turning tool according to its processing properties can be divided into rough turning tool and fine turning tool two kinds

2. Selection of geometrical parameters of turning tool

(1) The Angle between the two edges of the rough turning tool should be less than the conformal Angle, and the fine turning tool should be equal to the conformal Angle.

(2) Tip width Thick turning tool tip width should be 1/4 pitch width. Fine turning tool tip width should be 0. 05mm smaller than the tooth bottom width W.

(3) The longitudinal forward Angle thick turning tool is generally about 10° ~ 15°. In order to ensure the correct conformal Angle of fine turning tool, the forward Angle should be equal to 0°, but 5° ~ 10° should be taken in actual production.

(4) Longitudinal rear Angle is generally 6° ~ 8°.

(5) The working Angle of turning tool (front Angle and back Angle) has changed to some extent due to the influence of screw Angle. The size of the left and right side back Angle of the thread turning tool is related to the tool strength and sharpness, and affects the surface roughness of the thread tooth side. Therefore, the left rear Angle of turning tool αOL=(3° ~ 5°)+φ; Right rear Angle of turning tool αOR=(3° ~ 5°)-φ.

3. Steps of trapezoidal turning tool grinding

(1) After the rough grinding of the main and auxiliary parts, the tool tip Angle is initially formed.

(2) Forming a front Angle in front of rough and fine grinding.

(3) Fine grinding of the main rear tool surface, deputy rear tool surface. Correct with Angle template while grinding

4. Precautions for grinding

(1) When grinding both sides of the auxiliary rear cutter surface, the left and right rotation direction of the thread and the size of the screw Angle should be considered, and then determine the increase and decrease of both sides of the rear Angle.

(2) The cutting edge of turning tool should be smooth and straight, and the auxiliary insert on both sides must be symmetrical and the tool head cannot be skewed.

(3) High speed steel turning tools should be cooled in time to prevent annealing.

(4) After grinding the edge, the burr on the insert should be removed with an oil stone. Figure 3-17 Angle template

5. Tool installation

(1) Turning tool main insert must be as high as the center of the workpiece (with the spring tool bar should be about 0.2mm higher than the center of the workpiece), and should be parallel to the axis of the workpiece.

(2) The Angle bisector of the cutter head should be perpendicular to the axis of the workpiece, and the sample plate should be used for alignment and clamping (Figure 3-18) to avoid half Angle error of thread