SU1414509A1 - Parting-off tool - Google Patents

Abstract

The invention relates to the field of metal cutting, in particular to cutting cutters. The aim of the invention is to increase tool life by increasing the strength of the cutting part. On the cutting cutter, the main cutting edge is stepped. Its middle section is made with a facet along the entire length, and the side sections are inclined to the middle section. The back surface of the cutting tool is made convex. When operating with a cutting cutter, three independent streams of chips are formed due to the stepped main cutting edge, as well as the deviation of the side streams from the middle portion of the front surface, which reduces the forces and stresses in the cutting zone. 4 il.

Description

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The invention relates to the field of metal cutting, in particular to cutting cutters.

The purpose of the invention is to increase tool life by increasing the strength of the cutting part.

FIG. 1 shows a detachable cutter, side view; in fig. 2 - the same, view of the front surface, in FIG. 3 - the same view of the back surface; in fig. 4 is a section A-A in FIG. 2

The cutter contains a front surface 1, which is made stepped with a middle section 2 and two side sections 3 and 4. The middle section 2 is made protruding above the side sections 3 and A (i.e., sections are understated relative to the entire front surface), which form walls 5 and 6 of the middle stage 2. In addition, the side sections are made inclined to the middle section 2 and extended at an angle φ in the direction of the chip movement. The main rear surface 7 of the cutter is made convex (for example, cylindrical). When crossing the occlusal back surface 7 with the lateral surfaces. out stepped sections 5 and 6 are formed convexly lateral parts 8 and 9 of the main cutting edge located on an arc of radius R. In the middle section 2 of the front surface, chamfer 10 is formed, the pin 1 of which is less than its width b. At the intersection of the surface of the chamfer 10 with the rear surface 7, the chamfer part 11 of the main cutting edge is formed, and at the intersection of the middle section 2 of the front surface 1 not covered by the chamfer 10 with the rear surface 7, non-faceted parts 12 and 13 of the main cutting edge are formed. Angle (extensions of the side stepped portions 3 and 4 are selected according to the inequality

arcsin

b + b. B ---- (arcsin -;

where b is the width of the middle section 2

front surface 1 of the cutter; B — width of the cutter; R — radius of the convex back surface of the 7 cutter. The lower constraint (left in the formula) corresponds to the condition of uniform uniform along the cutting edge of its parts 8 and 9, when the side

Chip streams move along the normal to these parts of D midpoint edges. The upper limit (the right r in the formula) corresponds to the non-free cutting by the external corners (lines 14 and 15) of the cutter, when the outer edges of the side streams of chips formed by the latter dictate

0 the deviation angle in sections 3 and 4 of the entire chip flow. With the values of the width of the middle section equal to b (0.3-0.6) B, there is a uniform cutting by the side

5 parts of the main cutting edge, and at b (0.6-0.8) kV - not free cutting. Comparison of the largest values of the angle Cp of the expansion of the side stepped portions 3 and 4 of the proposed 0 I o cutter, limiting the operating values, is chosen according to the given inequality.

The tops 14 and 15 of the cutter are located below the chamfer part 11 of the middle

5, a section of the main cutting edge by an amount h of 0.1-0.8 mm. Front values; The corners on the surface of the chamfer 10 and on the side sections 3 and 4 are equal

0 - (-25), - (-10).

The length of the chamfer 10 in the middle section 2 in front of the first surface 1 is chosen equal to 1 (O, 4-0.9) b. The angle of inclination of the side portions 3 and 4 to the middle portion 2 of the front surface 1 is chosen paBHt.iM, 2-6. To reduce the friction of side streams of chips on the side walls (near the main cutting edge), the angle in the profile of the undersized stepped sections 3 and 4 is chosen equal to 80–85 °, and the radius of the bottom of these sections is g equal to g 0.2-0.5 mm .

0

Radius R of the back surface is R (0.9-3) B, where B is the width of the tool. With an increase in the hardness of the material being processed, the magnitude of the radius R, as well as the magnitude of the angles / fi jTj J should decrease.

The cutter works as follows. The middle section 2 of the cutters with parts 11–13 of the main cutting edge, as well as its parts 8 and 9, form three streams of chips, diluted to the height and not interfering with each other in width during the formation of chips. Parts 12 and 13 of the main cutting edge, not formed by fascoG, a larger rake angle (according to the angle | 1 to the f31

11), which defines a smaller shrinkage of the average chip flow along its edges, which leads to bending of the edges of the chip. As it moves along the front surface of the cutter, the average chip flow engages with the indicated bent edges for the free (upper) side of the chip side streams and, having a greater speed of movement (since in the middle section of the cutter, the cutting edges are characterized on average by large front corners and, moreover, The average chip flow does not deviate), deflects the side chip flows from each other and from the walls 5 and 6 of the middle stage 2, thereby reducing friction.

Independent chip formation of the three streams by the main cutting edge parts and the deviation of the side streams from the middle portion of the front surface ensures the reduction of forces and stresses in the cutting zone. Reducing the angles in the tan for the corners (tops) of the middle step and reducing the angles of expansion of the lateral steps increases the strength of the corners and the heat sink, which ultimately leads to a decrease in the resistance of the cutting tool when machining difficult-to-work materials.

The sharpening of the proposed cutter is simpler, and the design is technological A509

it, so rlk, the back surface is guided by one n ;; construction (and not three, as in the well-known one) and with a single formative movement — pumping.

Claims (1)

Invention Formula A cutting cutter with a stepped front surface forming the middle with a chamfer and side portions of the main cutting edge, the side portions of the front surface of which are made expanding from the main 1 € of the cutting edge at an angle f and inclined to its middle section, characterized in that tool durability by increasing the strength of the cutting part, the back surface of the cutter is made convex, and the chamfer in the middle section is not made on the entire length, and the angle (f extension of the side sections, selected according to equality . B + b,. In arcsin, r - (i ar: csin r-; where b is the middle portion of the front surface of the cutter, B - cutter width; R is the radius of the convex back surface of the tool. IPU2.1 1t 11 10 13 M 15 9 Fig.Z Aa (Rig.