Indexable hard alloy blade

Abstract

The indexable hard alloy blade is of an integral structure, a groove is formed in the position, close to a main cutting edge, of a front blade face, and an oval three-dimensional composite curved surface is contained in the groove; the indexable hard alloy blade is characterized in that a three-dimensional composite curved surface is arranged on the end portion of a cutting edge on the periphery of the blade, a circumferential accurate grinding belt is arranged on the end portion of the cutting edge on the periphery of the blade, and the three-dimensional composite curved surface is connected with the circumferential accurate grinding belt through a transition arc surface. The chip removal smoothness, the cutting edge sharpness and the transposition positioning precision are cooperatively improved, and meanwhile the overall service life is prolonged.

Description

Technical Field

[0001] This invention relates to the field of metal cutting, and in particular to an indexable carbide insert for turning, grooving and cross-cutting finishing. Background Technology

[0002] Most indexable carbide inserts currently in widespread use employ two-dimensional V-shaped or U-shaped chip evacuation grooves on the rake face, and the cutting edge is directly pressed into the outer periphery. Although this traditional structure is simple to manufacture, it exposes multiple limitations in actual turning and grooving processes.

[0003] Firstly, two-dimensional grooves can only achieve chip rolling within a limited feed and depth window. When machining with low feed or shallow grooves, long iron chips are easily generated and wrapped around the workpiece, which not only affects the surface roughness of the workpiece, but also requires frequent machine stops for cleaning.

[0004] Secondly, in order to improve wear resistance, a hard film layer is often sprayed on the outer edge, which leads to an increase in the radius of the cutting edge and a decrease in sharpness. However, if the cutting edge is finely ground first and then coated, problems such as uneven film thickness and cutting edge defects are likely to occur, making it difficult to balance sharpness and lifespan.

[0005] Third, traditional back-side positioning is mostly based on planar friction. After each rotation of the blade, indentations accumulate, causing angular and radial accuracy to rapidly decrease, affecting dimensional consistency. Summary of the Invention

[0006] This invention addresses the technical problem of existing indexable carbide inserts in achieving a balance between chip removal, cutting edge sharpness, repeatability, and service life. It proposes an integral, multi-curved composite chip removal structure for carbide inserts. By designing a slender elliptical three-dimensional groove on the rake face, setting a circumferential fine grinding belt on the outer periphery, and supplementing it with a corrugated back positioning surface and a composite PVD gradient coating, it achieves a comprehensive improvement in efficient chip removal, stable and sharp cutting edge, reliable indexing and positioning, and excellent wear resistance.

[0007] Specifically, the blade is an integral structure with a groove on its rake face near the main cutting edge. The groove includes an elliptical three-dimensional composite surface.

[0008] The cutting edge of the blade is provided with a circumferential fine grinding zone;

[0009] The three-dimensional composite surface and the circumferentially ground belt are connected by a transition arc surface.

[0010] In a preferred embodiment, the profile line along the direction perpendicular to the main cutting edge sequentially includes: an upwardly sloping slope extending inward from the cutting edge to form a positive rake angle; and a concave curved surface that transitions continuously with the slope.

[0011] In a preferred embodiment, the inclined slope has a zero to negative rake angle relative to the rake face and smoothly connects with the reference rake face.

[0012] In a preferred embodiment, the slope, the concave surface, and the transition surface are continuous with each other, forming a smooth S-shaped profile line for chip rolling, chip folding, and chip removal.

[0013] In a preferred embodiment, the indexable insert consists of an insert body and three cutting faces extending outward from the body. Each cutting face includes, from the outside in, a circumferential grinding zone forming a continuous cutting edge and a positive rake angle bevel integrated with the circumferential grinding zone.

[0014] In a preferred embodiment, a corrugated positioning surface is provided on the back of the blade around the central through hole. The corrugated positioning surface is composed of multiple radial bosses and recesses alternating. The top surface of the bosses is used to engage with the corrugated surface of the blade holder to achieve angular positioning and radial limiting of the blade.

[0015] In a preferred embodiment, there is an elongated elliptical three-dimensional groove that smoothly transitions to the front corner slope. The three sides have the same structure and can be rotated sequentially for use, thereby taking into account the sharpness of the cutting edge, the smoothness of chip removal, and the multiple usability.

[0016] In a preferred embodiment, the blade employs an ultrafine-grained WC-Co substrate and forms a TiAlN / AlCrSiN composite PVD coating on its surface.

[0017] Compared with the prior art, the combination of the S-shaped profile and the elliptical groove in this invention significantly expands the chip-fold window and reduces the entanglement of long chips; the circumferential fine grinding belt ensures sharpness while reducing stress concentration through the arc transition, and the gradient coating improves wear resistance and life. Attached Figure Description

[0018] Figure 1 It is a three-dimensional view of the blade, showing the approximate location of the triangular shape and the elliptical three-dimensional groove on the front face.

[0019] Figure 2 It is a three-dimensional view of the back of the blade, highlighting the corrugated positioning surface with a flower-like distribution around the central through hole.

[0020] Figure 3 It is a cross-sectional view along the normal of the cutting edge, showing the chip removal section of the chamfered band, the positive rake angle slope and the elliptical groove continuously forming an S-shaped curved surface.

[0021] Figure 4 It is a magnified view of the tool tip, emphasizing the smooth transition between the circumferential fine grinding zone and the three-dimensional groove at the tool tip.

[0022] Figure 5 This is a schematic diagram of the recommended process window for the cutting tool in medium carbon steel (MS) conditions. Detailed Implementation

[0023] The preferred embodiments of this application will be further described below with reference to the accompanying drawings, so that those skilled in the art can more clearly understand the technical solution and beneficial effects of the present invention. It should be understood that the relative positions, size proportions and shapes of the elements shown in the drawings are for illustration only and do not constitute a limitation on the scope of protection of this application; unless otherwise expressly stated, the same or similar reference numerals in the drawings represent the same or similar parts, and in actual manufacturing and application, they can be equivalently replaced or functionally adjusted without departing from the spirit of this application.

[0024] like Figure 1 As shown, the cutting tool 100 of this application is mainly used for finishing processes such as external turning, end face turning, narrow groove cutting and chamfering of metal materials such as medium carbon steel, low alloy steel and stainless steel.

[0025] The indexable insert 100 consists of an insert body 110 and three cutting surfaces 112 extending outward from the body. The indexable carbide insert has an overall body that is approximately triangular, with a through hole 111 in the center. Three cutting surfaces 112 extend outward along the three outer edges of the body, and the three cutting surfaces 112 have the same structure and are symmetrically distributed around the through hole 111 at 120°.

[0026] Furthermore, the cutting edge 112 of the blade is located at the bottom outer edge, where the chips are guided below and outside the blade, and will not accumulate on the upper surface of the main body 110. The large cross section of the main body 110 is located above it, which can effectively withstand the cutting reaction force.

[0027] Furthermore, the blade 100 has a through hole 111 at its center. The cross-section of the through hole 111 gradually narrows from the back side towards the front face 112. It can be designed as a tapered shape with a straight generatrix or a hyperbolic tapered surface. This tapered structure can form a transition fit with the tapered clamping screw or support sleeve when the screw is tightened, producing a coupling effect of axial clamping and radial self-centering, ensuring that the blade 100 can be reliably positioned after each indexing. At the same time, the hyperbolic surface has a greater curvature at the small end, which can disperse the clamping stress and provide a slight spring force when loosening, making the blade 100 easier to install and remove. This not only improves the clamping rigidity and tool changing efficiency, but also reduces the risk of wear caused by hard contact between the blade hole wall and the screw head.

[0028] like Figure 2As shown, the back of the blade 100 is provided with a corrugated positioning surface 113 around the central through hole 111. The corrugated positioning surface 113 is composed of multiple radial bosses 114 and recesses 115 alternatingly. The top surface of the bosses 114 is used to engage with the corresponding corrugated surface of the tool holder to achieve angular positioning and radial limiting of the blade 100. The bosses 114 and recesses 115 are connected by an arc transition to form a continuous peak-valley curve. When the clamping screw or clamping block acts on the blade 100, the top surface of the peak engages with the corresponding corrugated surface of the tool holder to achieve surface-to-surface engagement positioning, which not only provides reliable angular positioning and radial limiting, but also evenly distributes the clamping force and reduces local pressure.

[0029] Furthermore, the trough 115 provides a clearance for chip removal and coolant flow, preventing cutting chips or deposits from getting stuck on the back of the insert 100, thus maintaining clamping rigidity and repeatability after multiple indexing operations.

[0030] Reference Figure 3 and Figure 4 As shown, the blade 100 is an integral structure, with a groove 121 provided on its rake face 120 near the main cutting edge. The groove 121 includes an elliptical three-dimensional composite curved surface 122. The cutting edge end of the outer periphery of the blade 100 is provided with a circumferential fine grinding belt 123. The three-dimensional composite curved surface 122 and the circumferential fine grinding belt 123 are connected by a transition arc surface 124.

[0031] Furthermore, each cutting edge 112 includes, from the outside to the inside, a circumferential fine grinding belt 123 forming a continuous cutting edge, a positive rake angle slope 125 integrated with the circumferential fine grinding belt 123, a three-dimensional groove 121 smoothly connected with the slope, and the three cutting edges 112 together constitute a continuous cutting edge, which can be used in sequence according to the indexing angle to extend the life of the cutting tool 100.

[0032] Furthermore, the groove 121 is structured into a first part 126 and a second part 127. The first part 126 is formed on the cutting surface 112, and its contour gradually deepens inward along the positive rake angle slope 125 of the cutting surface 112 to initiate chip rolling and provide a sharp chip removal opening. The second part 127 is formed on the main body 110, and transitions with the bottom of the groove of the first part 126 through a smooth arc surface 1271, continuing to extend inward into the interior of the main body 110. The two parts work together to form a continuous elliptical S-shaped three-dimensional chip removal channel: the first part 126 is responsible for rapid chip rolling and folding, and the second part 127 provides sufficient chip-carrying space for the chip flow and guides it to the outside of the cutting tool, while avoiding a reduction in overall strength due to the entire groove 121 being machined on the weak cutting surface 112. This ensures that the cutting surface 112 remains sharp while the main body 110 still has sufficient rigidity and heat dissipation volume.

[0033] Furthermore, the elliptical three-dimensional composite surface 122 extends continuously from the first part 126 to the second part 127. The front section is adjacent to the circumferential fine grinding zone 123 on the cutting surface 112 to form a chip flow introductory zone. The middle section is recessed in the cutting surface 112 and transitions to the main body 110 to form a chip-containing zone. The rear section gradually rises on the main body 110 to form a chip flow outtroductory zone. The three curved surfaces are smoothly connected to form a continuous flow channel for chip rolling, chip folding, and chip removal without significantly weakening the strength of the cutting surface 112.

[0034] Continue to refer to Figure 3 and 4 The elliptical three-dimensional composite surface 122, along a cross-section perpendicular to the main cutting edge, sequentially includes: an upwardly sloping slope 128 extending inward from the cutting edge, forming a positive rake angle; a concave surface 124 continuously transitioning to the slope 128; a first part surface 130 following the concave surface 124; and a second part surface 131 following the first part surface 130. The slope of the first part surface 130 at the same height is greater than the absolute value of the slope of the second part surface 131, i.e., the slope of the first part surface 130 is greater than the absolute value of the slope of the second part surface 131. The first part of the curved surface 130 is steeper than the second part 131. Its advantage lies in utilizing the steep slope of the first part of the curved surface 130, allowing the chip to obtain sufficient upward speed and curling driving force as soon as it leaves the cutting edge, quickly completing the initial chip folding and avoiding melting or accumulation at the cutting edge. Subsequently, the transition to the second part of the curved surface 131 with a gentler slope can smoothly guide the chip into the depth of the groove 121 while reducing the chip's upward throw angle, allowing the chip curling radius to gradually increase without secondary breakage. This achieves a segmented synergistic effect of rapid curling followed by smooth chip removal. This structure ensures smooth chip removal, reduces local thermal stress concentration at the cutting edge, significantly extends the life of the insert 100, and improves the surface quality of the workpiece.

[0035] Furthermore, the inclined slope 128 has a zero to negative rake angle relative to the rake face 120 and smoothly connects with the reference rake face 120. Further, the inclined slope 128 forms a zero to negative rake angle along the cutting feed direction and transitions with the reference rake face 120 in a continuous curvature manner. After achieving rapid chip removal in the positive rake angle segment, the zero to negative rake angle segment can effectively reduce the peak normal pressure near the cutting edge, suppressing chip adhesion and cutting heat concentration; at the same time, the smooth transition avoids geometric abrupt changes, thereby reducing tool vibration, improving cutting edge strength, and maintaining stable cutting force and surface quality under intermittent or heavy-load cutting conditions.

[0036] Furthermore, the slope 128, the concave curved surface 124, and the transition curved surface are continuous with each other, and the overall outline presents a smooth S-shaped profile trend of "rising first, then falling, then rising again" in cross-section, which is used to complete the chip rolling, chip folding, and smooth chip removal in sequence. It should be noted that the "S-shaped profile" here is not limited to the standard S-curve in a strict mathematical sense. It can be a composite curve with any curvature continuity that meets the aforementioned functional requirements, including but not limited to asymmetric S-shapes, piecewise polynomial curves, or spline curves, etc.

[0037] Furthermore, the blade 100 employs an ultrafine-grained WC-Co substrate 140 and forms a TiAlN / AlCrSiN composite PVD coating on its surface. The blade 100 uses an ultrafine-grained WC-Co substrate to refine the grains, significantly improving bending strength and chipping resistance. A TiAlN transition layer and an AlCrSiN wear-resistant layer are sequentially deposited on the substrate surface to form a gradient composite PVD coating.

[0038] The TiAlN transition layer matches the thermal expansion coefficient of the substrate 140, which can enhance the adhesion of the film and inhibit high-temperature softening. The outer AlCrSiN wear-resistant layer, rich in Al, Cr, and Si, can generate a dense Al-Cr oxide film in situ under the action of cutting heat, thereby greatly improving the oxidation resistance and anti-chip wear ability. The gradient increase in hardness and internal stress layout not only avoids film cracks caused by sudden changes in internal stress, but also ensures that the outer layer maintains high red hardness and high wear resistance, so that the cutting tool 100 can still maintain a sharp cutting edge under high temperature, heavy load and intermittent cutting environment.

[0039] like Figure 5 As shown, the recommended feed depth of cut window of the insert 100 in this application for medium carbon steel MS material covers a feed range of 0–0.15 mm / rev and a depth of cut range of 0.7–3 mm, presenting a wider and flatter rectangular working area than conventional two-dimensional grooving inserts. This tolerant process range, combined with the chip removal structure of the slender elliptical three-dimensional groove 121 and S-shaped profile, allows for rapid and smooth chip removal under both low-feed shallow cutting and high-feed deep cutting conditions. The circumferentially finely ground chamfered band 123 provides a uniformly sharp cutting edge, significantly reducing cutting resistance at low feed rates while maintaining edge strength at high depths of cut. The corrugated positioning surface 113 on the back side, through multi-peak and trough engagement, ensures that the insert 100 maintains angular and radial accuracy after multiple indexing operations, thus outputting consistent machining dimensions throughout the entire process window.

[0040] The gradient TiAlN / AlCrSiN coating 141 exhibits excellent anti-oxidation and anti-chip wear properties in the high-load cutting section, preventing the tool 100 from experiencing a sudden drop in life due to high temperature. Compared with traditional tools that can only barely achieve stable machining within a narrow "strip" or "band" parameter range, the tool 100 of this application significantly widens the usable process window, achieving the technical advantage of one-time coverage of low and medium feed and shallow and deep cutting, reducing the frequency of tool changes and machine adjustments, and reducing inventory pressure.

[0041] In summary, this application provides an integral indexable carbide insert 100. Its core technical solution utilizes a slender elliptical three-dimensional groove 121 with a circumferentially finely ground chamfered band 123 and a smooth S-shaped cross-section. This achieves rapid chip curling, chip breaking, and smooth chip removal on the insert's rake face 120. A corrugated positioning surface 113 is arranged on the back side to ensure angular and radial accuracy after multiple indexing operations. Furthermore, an ultrafine-grained WC-Co matrix 140 with gradients is employed.

[0042] The TiAlN / AlCrSiN composite PVD coating 141 enhances high-temperature wear resistance and anti-chip adhesion. Through a three-sided, indexable tool facet 112 structure, this invention significantly widens the stable machining window of 0–0.15 mm / rev feed and 0.7–3 mm depth of cut, achieving a synergistic effect of low-resistance cutting, high surface quality, and long tool life. Simultaneously, it reduces tool change and machine setup frequency, decreases inventory types, and improves production efficiency, demonstrating outstanding comprehensive technical advantages and industrial application value.

Claims

1. An indexable carbide cutting tool, characterized in that, The blade is an integral structure with a groove on its rake face near the main cutting edge. The groove includes an elliptical three-dimensional composite surface. The cutting edge of the blade is provided with a circumferential fine grinding belt; The three-dimensional composite surface is connected to the circumferential precision grinding belt through a transition arc surface.

2. The indexable carbide insert according to claim 1, characterized in that, The profile line along the direction perpendicular to the main cutting edge includes, in sequence: an upwardly sloping slope extending inward from the cutting edge, forming a positive rake angle; and a concave curved surface that transitions continuously with the slope.

3. The indexable carbide insert according to claim 2, characterized in that, The inclined slope has a zero to negative rake angle relative to the rake face and smoothly connects with the reference rake face.

4. The indexable carbide insert according to claim 3, characterized in that, The slope, concave surface, and transition surface are continuous with each other, forming a smooth S-shaped profile line for chip rolling, chip folding, and chip removal.

5. The indexable carbide insert according to any one of claims 1-4, characterized in that, The indexable carbide insert consists of an insert body and three cutting faces extending outward from the body. Each cutting face includes, from the outside in, a circumferential grinding zone forming a continuous cutting edge and a positive rake angle bevel that is integrated with the circumferential grinding zone.

6. The indexable carbide insert according to claim 5, characterized in that, The back of the blade has a corrugated positioning surface around the central through hole. The corrugated positioning surface is composed of multiple radial protrusions and recesses alternating. The top surface of the protrusions is used to engage with the corrugated surface of the blade holder to achieve angular positioning and radial limiting of the blade.

7. The indexable carbide insert according to claim 5, characterized in that, It also includes an elliptical three-dimensional groove that smoothly transitions to the front corner slope. The three sides have the same structure and can be rotated sequentially for use, thus taking into account the sharpness of the cutting edge, the smoothness of chip removal, and the multiple usability.

8. The indexable carbide insert according to claim 1, characterized in that, The blade uses an ultrafine-grained WC-Co matrix and forms a TiAlN / AlCrSiN composite PVD coating on its surface.

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