RU2463130C1 - Rotary cutter - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: rotary cutter is shaped to polygonal body with cutting edge shaped to polygon in pane perpendicular to its rotational axis. Cutting part of polygonal body with separation grooves made at body vertices consists of N teeth with straight cutting edge and tooth face surface made at angle γ to cutting plane varying fro two to five degrees. Polygonal body vertices may be rounded to r=0.1-0.4 mm.

EFFECT: simplified cutter grinding.

2 cl, 6 dwg

Description

The invention relates to the field of engineering and can be used in the processing of shafts from various structural materials.

Known rotary cutting insert [patent application RU No. 2008148805, IPC VV 27/06, publ. 07/20/2010] with the first and second surfaces of the plate, generally having a triangular shape, three side surfaces and at least one cutting protrusion located in the region of the angle between the first and second side surfaces, the cutting protrusion is generally M-shaped and includes at least a first and second cutting teeth, wherein at least a first cutting edge is formed on at least a first cutting tooth located in a transition region to a first surface of the insert, and a second cutting edge is formed on at least a second cutting tooth I cutting edge, located in the transition to the second surface of the plate, and the first direction of chip removal related to the first cutting edge forms an angle α with a second direction for chip removal related to the second cutting edge, the first and second cutting edges are associated with the first and a second chip guide for guiding the chip in the direction of chip evacuation, the first chip guide for guiding the chip includes at least a first groove on a first surface of the plate, which is generally perpendicular perpendicular to the first direction of chip removal between the first and second side surfaces, and the second guide for chip removal includes at least a second groove on the second surface of the plate, which is generally perpendicular to the second direction of chip removal between the first and second side surfaces.

The disadvantages of the known design are the difficulty in manufacturing and rapid wear due to the fact that the cutting edge consists of a large number of intermittent sections. In addition, low quality workpiece processing, as the profile of the cutting edge during processing of the workpieces will give a kinematic undulation - a consequence of intermittent cutting.

The closest technical solution to the claimed is a method of blade processing of shafts with a profile of "equiaxial contour" [autosvid. 1,126,375; MKI ³ V23V 1/00, publ. November 30, 1984], in which the rotation of the machined shaft is reported, and the tool is informed of the longitudinal feed and harmonic transverse movement, the rotation axes of the tool and shaft being set to intersect at right angles. As a tool, use a rotary cutter made in the form of a polyhedral cup (body), the cutting edge of the cutting part of which has a polygonal shape in a plane perpendicular to the axis of its rotation. The linear rotational speed of the tool is set at least an order of magnitude greater than the linear rotational speed of the work shaft. Processing with the specified cutter is performed in such a way that the main direction of chip deformation occurs along the cutting edge of the cutter. Cutting due to the constructive feed occurs in the profile section with an increasing radius vector.

The disadvantage of this design of the cutter is that due to the arc shape of the edges of the cutting edge when it is formed during sharpening along the front and rear surfaces, a significant deviation from the flatness of the arrangement of the edges of the cutting edge occurs. In addition, when sharpening the cutter, special grinding machines with the planetary movement of the grinding wheel or workpiece are required.

The objective of the invention is to create a technological design of a rotary cutter, when sharpening which eliminates the need to use special grinding machines, as well as improving the accuracy of the location of the edges of the cutter in the plane.

The problem is solved in that in a rotary cutter made in the form of a multifaceted body, the cutting edge of the cutting part of which has a polygonal shape in a plane perpendicular to the axis of rotation, according to the invention, the cutting part of the polyhedral body of the cutter, on the tops of which the dividing grooves are made, consists of N teeth, the cutting edge of each tooth is straightforward, and its front surface is made at an angle γ to the cutting plane from 2 to 5 degrees. The vertices of the polyhedral body are made with a fillet radius r from 0.1 to 0.4 mm.

The accuracy of the location of the cutter faces in the plane is increased due to the fact that the cutting edge of each tooth is made rectilinear. Performing on the vertices of the multifaceted body of the cutter, the cutting part of which consists of N teeth, separation grooves allows you to grind the tool on universal grinding machines with the output of the tool through the separation groove. The execution of the vertices of a polyhedral body with a fillet radius r from 0.1 to 0.4 mm allows to increase the durability of the rotary cutter.

The invention is illustrated by drawings, where

figure 1 shows the proposed cutter;

figure 2 - the proposed cutter, a top view;

figure 3 is a section along aa in figure 2;

figure 4 is an embodiment of the proposed cutter, top view;

figure 5 shows a diagram of the processing of the shaft;

6 is a diagram of the processing of the shaft, left view.

Symbols adopted in the drawings:

a is the width of the separation groove;

V _B is the rotation speed of the machined shaft;

V _p is the speed of rotation of the cutter;

K - polygonal cutting edge in the form of a cutting polygon;

S _gr - total feed per tooth incisor;

S _ol - longitudinal feed;

S _K - constructive feed;

N is the number of teeth of the cutter;

ρ _min is the minimum radius vector of the cutting edge;

ρ _max - the maximum radius vector of the cutting edge;

r is the fillet radius;

γ is the rake angle.

The rotary cutter is a polyhedral body 1, for example a trihedral (see figure 1), with a landing hole 2 and a cutting part consisting of N teeth. Each tooth contains a rear 3 and front 4 surfaces that form a straight cutting edge 5. The cutting edges 5 formed on each tooth and placed on a plane perpendicular to the axis of rotation of the rotary cutter (Fig. 2) form a cutting polygon between each other. The front 4 tooth surface (Fig. 3) is made at an angle γ to the cutting plane from 2 to 5 degrees. On the vertices of the polyhedral body 1 of the incisor, dividing grooves 6 with a width a are made.

For the embodiment (Fig. 4), the vertices of the polyhedral body 1 with dividing grooves 6 are made with a fillet radius r from 0.1 to 0.4 mm.

Sharpening of the cutter is carried out on the front 4 or rear 3 surfaces of the teeth, depending on the type of wear.

The work of the proposed rotary cutter is as follows.

The processed shaft 7 rotates at a speed of V _B , and the cutter 8, having a polygonal cutting edge K, rotates at a speed of V _p to meet the rotation of the shaft 7. The axis of rotation of the cutter 8, installed using the mounting hole 2, on the spindle of the machine tool assembly is perpendicular to the axis of rotation the processed shaft 7, in addition, the axis of rotation of the tool should be at the same height as the axis of rotation of the shaft.

The cutting conditions are determined by the design parameters of the cutter, as well as the type of tool and processed material.

The cutter 8 makes a harmonic transverse movement according to a sinusoidal or cone-shaped law and has a longitudinal feed S _av Periodically, when the cutter 8 rotates in the cutting zone, the working tooth is replaced, due to which the working cutting edge 5 is updated, while the remaining teeth of the cutter cool down. With this mode of operation, COTS (cutting lubricants) is not required.

Cutting due to the constructive feed S _K occurs due to a change in the radius vector ρ of the cutting edge 5, while the sheared chips formed in the form of separate sections of the wedge type descend along the front surface of the 4 teeth with sliding along the cutting edge 5 of the tool.

The dividing groove 6 serve to increase the manufacturability of the cutter, simplifying the regrinding of the cutting edge 5 due to the possibility of the grinding tool exit through the dividing groove 6.

The experimental verification was carried out on a model 16K20 screw-cutting lathe using a tool drive consisting of an electrospindle, an arm, and a frequency converter. Specially ground polyhedral plates together with the mandrel are mounted on the shaft of the electrospindle. When processing a batch of shafts (D = 50 mm; L = 70 mm) with a polygonal rotary cutter (ρ _max = 9.63 mm; ρ _min = 7.94 mm; N = 3), the depth of cut ranged from 0.1 mm to 2 mm. Shaft feed (circular feed) from 0.2 mm / rev to 3 mm / rev. The cutting speed ranged from 12,000 rpm to 18,000 rpm. Verification showed that the treated surfaces with cutters with an arc polygonal cutting edge [ed. 1126375 USSR; MKI ³ V23B 1/00.] And the proposed one have the same surface quality parameters (roughness) Rα = 1.25 ÷ 2.5 μm. In addition, there is no formation of kinematic undulation. When sharpening a tool with straight cutting edges, it was possible to achieve a much smaller deviation from the plane of the cutting edges than with arc edges. It was revealed that the cutting depth does not significantly affect the surface roughness. In the course of the research it was revealed that guaranteed chip crushing is ensured. In addition, there is no build-up, due to the lack of heating of the cutting tool and the gathering of chips with relative sliding along the cutting edge.

Claims (2)

1. The rotary cutter, made in the form of a multifaceted body, the cutting edge of the cutting part of which has a polygonal shape in a plane perpendicular to the axis of rotation, characterized in that the cutting part of the polyhedral body, on the tops of which the dividing grooves are made, consists of N teeth, the cutting edge each tooth is straightforward, and its front surface is made at an angle γ to the cutting plane from 2 to 5 °. 2. The rotary cutter according to claim 1, characterized in that the vertices of the polyhedral body are made with a fillet radius r from 0.1 to 0.4 mm.

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