An indexable insert and tool assembly for fine depth of cut finishing.

Abstract

This utility model discloses an indexable insert and tool assembly for fine machining with minute depth of cut. The insert body has a first and a second cutting face and a central through hole. The cutting edge is formed by the intersection of the two cutting faces. The two cutting faces have a chip removal groove structure along the cutting edge direction, including: multiple wavy ridges extending laterally by at least 60% of the cutting edge length, with a peak-to-valley height h₁ of 0.02-0.15 mm; a first chip removal groove with a rake angle of +5° to +10° between the first ridge and the cutting edge; and a second chip removal groove with a rake angle of −5° to 0° between the first and second ridges and the cutting edge, forming a stepped cutting face; the tool tip area has a triangular pyramidal induced protrusion, with the highest point height h₂ satisfying 1.1h₁≤h₂≤1.5h₁.

Description

Technical Field

[0001] This invention relates to the field of metal cutting tool technology, and in particular to an indexable carbide insert and its chip removal groove structure suitable for finishing work with small depth of cut (cutting depth ap ≤ 0.30 mm). Background Technology

[0002] With the increasing demands for surface quality and dimensional accuracy in industries such as aerospace, medical devices, and precision molds, high-efficiency finishing processes with small depths of cut and high feed rates are widely adopted. In these processes, the common depth of cut is only 0.05mm to 0.30mm, and the feed rate f is less than 0.10mm / rev. Due to the extremely thin cutting layer, which is insufficient to form sufficient deformation, existing chip evacuation grooves often cannot establish sufficient bending stress and pressure difference on the first cutting face of the insert to achieve reliable chip curling and chip breaking.

[0003] This can lead to many problems, such as long or strip-shaped chips wrapping around the tool and workpiece, damaging the machined surface and affecting automated production; another problem is that cutting heat is concentrated on the cutting edge and cannot be carried away in time, causing premature wear or chipping of the tool tip; yet another problem is that in order to avoid chip entanglement, the feed rate can only be reduced or the tool clearance angle can be increased, which causes both cutting efficiency and tool strength to decrease simultaneously.

[0004] To address the aforementioned technical challenges, the chip removal grooves on cutting tools currently on the market are mainly classified as "F-type (finishing)," "M-type (medium depth of cut)," and "LL-type (ultra-light cutting)." Their common characteristics are: relying on a single or a few straight / circular grooves to induce chips; the chip removal groove geometry design primarily considers the conventional depth of cut; and the tool tip area is typically a simple chamfer or a small fillet, lacking specific control over chip behavior at small depths of cut. At depths of cut ap ≤ 0.30, these groove types generally result in chips that only curl without breaking to form long, ductile chips.

[0005] Therefore, how to achieve stable chip breaking within a small cutting depth range while maintaining a sharp cutting edge and blade strength has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] To address the aforementioned shortcomings, this invention proposes a combined structure that forms a three-dimensional wavy convex ridge with a stepped double rake angle chip removal groove and a frustum-shaped inducing protrusion along the entire length from the tool tip to the main cutting edge. This structure enables chips to bend rapidly, accumulate stress, and be cut off in a timely manner even under extremely thin cutting layer conditions, thus balancing chip control, tool life, and workpiece surface quality.

[0007] One technical solution of the present invention is as follows:

[0008] An indexable insert for fine depth-of-cut finishing, comprising:

[0009] The blade body has a first cutting surface and a second cutting surface;

[0010] A through hole is located in the center of the blade body to achieve clamping and fixing with the blade holder;

[0011] The cutting edge is formed by the intersection of the first cutting face and the second cutting face;

[0012] A chip removal groove structure is provided on the first and second cutting faces along the cutting edge direction. This chip removal groove structure is used to achieve chip curling or chip breaking under conditions of cutting depth ap = 0.05mm-0.30mm and feed rate f = 0.02mm-0.10mm / rev. The chip removal groove structure includes...

[0013] Multiple wavy ridges extend laterally, covering at least 60% of the cutting edge length, with a peak-valley height h1 of 0.02mm to 0.15mm.

[0014] The first chip removal groove is located between the first convex ridge and the cutting edge, with a bottom rake angle of +5° to +10°.

[0015] The second chip removal groove, located between the first and second protruding edges and the cutting edge, with a bottom rake angle of −5°-0°, forms a stepped tool face with the first chip removal groove.

[0016] The induced protrusion, located in the tip region and appearing as a triangular pyramid when viewed from above, has a maximum height h2 that satisfies the condition 1.1h1≤h2≤1.5h1 on the first cutting surface.

[0017] Preferably, the blade also has the following improved features:

[0018] In the first aspect, the pitch P between adjacent peaks of the first convex ridge is 0.20mm to 0.50mm.

[0019] Secondly, the apex of the induced protrusion points to the cutting feed direction and has an angle of 30° to 60° with the cutting edge.

[0020] Thirdly, the bottom width of the first chip removal groove is 0.10mm~0.30mm;

[0021] Fourthly, the blade body is made of WCCo cemented carbide, and the first cutting surface is covered with a TiAlN-based nano-multilayer PVD coating with a thickness of 1µm~3µm.

[0022] Fifthly, the blade back angle is set to 7°~11°.

[0023] Sixthly, the peak height of the convex ridge gradually decreases along the direction of the cutting edge to improve chip control capability.

[0024] Seventhly, the blade has an 80° or 55° rhomboid shape and can be interchanged with ISO standard tool holders.

[0025] The present invention also provides a cutting tool assembly, including a tool holder and the aforementioned indexable insert mounted on the tool holder.

[0026] Beneficial technical effects

[0027] The indexable insert of this invention has a reasonable structure and efficient chip removal, and is particularly suitable for use in the machining of stainless steel, aluminum alloy and high temperature alloy materials in the case of micro-depth cutting. It can significantly improve the surface quality of the machined material and extend the tool life.

[0028] The present invention, with the above improvements, has at least the following advantages over the prior art: it solves the persistent problem of continuous chip entanglement caused by conventional groove designs; multiple peaks and valleys provide multiple initial chip sources for chip formation, avoiding failure at a single chip entanglement point; the decreasing peak height design of the second cutting face balances the sharpness of the cutting tip with the strength of the middle section; it actively triggers transverse chip cracking under micro-feed conditions, preventing the generation of long, ribbon-like chips in the cutting tip area; it also acts as a local reinforcing rib, reducing the probability of cutting tip chipping. It is easily implemented on existing cemented carbide pressing + PVD second cutting face coating production lines. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the three-dimensional structure of the indexable blade of the present invention.

[0030] Figure 2 This is a top view schematic diagram of the indexable blade of the present invention.

[0031] Figure 3 This is a side view schematic diagram of the indexable blade of the present invention.

[0032] Figure 4 This is a schematic diagram showing the applicable range of the cutting blade of the present invention in terms of processing parameters. Detailed Implementation

[0033] The following embodiments are in conjunction with the appendix Figure 1-4 The indexable insert for precision machining with minute depth of cut proposed in this invention is described in detail. Unless otherwise specified, the dimensions, angles, parameters, etc., in this embodiment are only preferred ranges or typical values, and do not constitute a limitation on the scope of protection defined by the claims. Example

[0034] like Figure 1 The cutting insert shown is used for high-efficiency finishing processes with small depth of cut and high feed rate. It is used in aerospace, medical devices and precision molds. The surface is provided with mounting holes. The tool body conforms to ISO D-SCLCR / L, D-SDUCR / L and other tool holders, which facilitates interchangeability with guide rods using this standard.

[0035] The blade body 100 includes a first cutting face 1 and Figure 2 .

[0036] The blade body is generally rhomboid in shape, with a top view angle α of 50°±10° at the head of the rhombus. The side length L1 is approximately 10.0 mm, and the thickness H1 is approximately 5.0 mm. A through hole 3 is provided in the center of the body, with a diameter of approximately 3-5.0 mm. This through hole is used for screw clamping onto the tool holder specified in ISO1832.

[0037] Furthermore, the cutting edge is formed by the intersection of the first and second cutting faces, with a sharp edge and ultrasonic polishing treatment, resulting in a cutting circle R < 0.02 mm;

[0038] Reference Figure 4 From the side, it can be seen that the height of the cutting edge is not uniform, and the height of the cutting edge decreases in a gradient as they approach each other. From the tip of the blade to the rear of the blade, there is a clear wavy and stepped structure. The first convex ridge is an arc-shaped protrusion that rises upward in a continuous curve along the side profile, with a peak-valley height h1 of approximately 0.02–0.15 mm.

[0039] Between the first protruding ridge 51 and the cutting edge, a slightly inclined plane can be seen, which is the first chip removal groove 41. Its bottom face angle is +5° to +10° and its width w1 is about 0.1–0.3 mm.

[0040] Furthermore, the first chip removal groove is located between the cutting edge and the first convex ridge, with a cross-sectional slope (groove bottom front angle) α1=+8°, a groove bottom width W1=0.20mm, and a depth of approximately 0.10mm.

[0041] Furthermore, a distinct step is formed between the first chip removal groove 41 and the second chip removal groove 42, which facilitates the initial chip breaking in the first stage under shallow cutting depth conditions.

[0042] Following the first chip removal groove 41 is the second convex ridge 52, which has a wavy shape. Its shape is similar to the first convex ridge, but its height and pitch are slightly different.

[0043] Furthermore, the pitch P1 between adjacent peaks of the first convex ridge is 0.20mm-0.50mm, and the pitch p2 between adjacent peaks of the second convex ridge is 0.51mm-1mm.

[0044] Furthermore, the second chip removal groove has a front angle of –5° to 0° at its bottom. The second chip removal groove 42 and the first chip removal groove 41 form a stepped double-stage cutting surface, which increases the chip breaking efficiency.

[0045] like Figure 2 As shown, after the second convex ridge 52 are the third convex ridge 53 and the fourth convex ridge 54. These convex ridges form a cutting edge with alternating peaks and valleys, and the cutting edge presents a wavy shape.

[0046] Furthermore, the first to fourth convex ridges (labeled 51-54) are distributed laterally along the cutting edge length L, accounting for approximately 50%-70% of the total. The pitch between adjacent peaks is 0.2-1 mm.

[0047] Furthermore, the second chip removal groove is located between the first convex ridge 51 and the second convex ridge 52, with a front angle α2 = –3° and a bottom width W2 = 0.15 mm. It is arranged in a stepped pattern with the first chip removal groove, and the height of the two steps is h1.

[0048] The cutting tip includes an inducing protrusion 60, forming a three-dimensional triangular pyramid with a vertex 61 at approximately 65°. The height of the vertex relative to the peak of the first convex ridge is h2 = 1.2h1. The vertex points in the cutting feed direction 70 with an included angle β = 45°.

[0049] Furthermore, the blade material is an ultrafine-grained WC–8Co cemented carbide, which is sintered and then coated with a TiAlN-based nano-multilayer coating by PVD process, with a coating thickness of approximately 2.0 μm.

[0050] like Figure 4 The left axis of the chart shows the cutting depth ap ≤ 0.5 mm, feed rate f ≈ 0.02–0.10 mm / rev, and cutting speed vc = 180 m / min, which can machine 316-column stainless steel. The recommended operating range for three types of inserts is: (depth of cut 0.5–2 mm, feed rate 0.08–0.17 mm / rev) and BX (micro-depth of cut finishing type, used only under conditions of ap ≤ 0.5 mm, f ≈ 0.02–0.10 mm / rev).

[0051] The right figure is a side cross-sectional view of the chip removal groove of the cutting tool of model DCGT11T302HBX of this invention. The horizontal projection length (pitch) of the wavy ridge in the cross-sectional direction is 0.3 mm, and the rake angle of the groove bottom is 10°. Together, they form a chip breaking structure combining steps and ridges, ensuring efficient chip breaking even under small depth of cut and low feed conditions, avoiding long swirling chips and obtaining excellent surface quality. The length of the curved spiral chips obtained from swirling or short chip breaking is about 5–10 mm; the surface roughness Ra≤0.6μm; and the tool durability can reach a material removal rate of 12000 mm³ / min.

[0052] Furthermore, the aforementioned cutting blade is mounted on a SHKCR1212-1.5 tool holder, requiring only one M5×0.8 screw for secure positioning, forming a tool assembly. This tool assembly can be used in the processing of consumer electronics products, such as the stainless steel frame of smartphones; or in the processing of miniature bearings for precision medical products, etc. Example

[0053] To meet the machining requirements of different narrow groove surfaces or fine contours, the parameters of the tool in Example 1 are adjusted as follows in this embodiment:

[0054] Firstly, the blade body is 55° rhomboid in shape, with a side length of 4.0mm and a thickness of 2.8mm. The through-hole diameter is φ4.5mm.

[0055] Secondly, the wavy ridge pitch P=0.45mm, and the peak-valley height h1=0.05mm (accounting for about 1 / 56 of the blade thickness).

[0056] Thirdly, the front angle of the first chip removal groove is α1 = +6°, and the bottom width of the groove is W1 = 0.12 mm; the front angle of the second chip removal groove is α2 = –1°, and the bottom width of the groove is W2 = 0.10 mm.

[0057] Fourthly, the height of the induced protrusion is h2 = 1.3h1 ≈ 0.065 mm; the apex points in the feed direction, and the included angle β = 50°.

[0058] Fifthly, the rear angle γ = 7°; the front angle ϕ ≈ 18°.

[0059] Sixthly, the blade material is the same as WC–8Co, and the TiAlN coating thickness is 1.5μm.

[0060] Seventhly, the peak pitch P can be adjusted within the range of 0.20mm–0.50mm, and the peak-valley height h1 can be set within the range of 0.02mm–0.15mm according to the hardness of the material to be processed, so as to optimize the chip breaking effect.

[0061] Eighthly, in addition to TiAlN, PVD coatings with better high-temperature lubricity, such as TiSiN and AlCrN, can also be used.

[0062] Ninthly, the two types of blades mentioned above can be interchanged with the 80° and 55° tool holders specified in ISO 26623-3, respectively, to meet the requirements of versatility.

[0063] This implementation followed the machining parameters ap=0.05mm, f=0.03mm / rev, vc=200m / min, and the material was aluminum alloy (6061-T6). Machining tests were conducted, and the results showed excellent short chip breaking performance with no chip entanglement; the surface roughness Ra≤0.4μm; and the tool life>8000mm³ / min.

[0064] This indexable insert is particularly suitable for finishing stainless steel, high-temperature alloys, and small depth-of-cut machining, and can also be widely used in micro-milling and precision CNC milling machines.

Claims

1. An indexable insert for fine-depth cutting, comprising: The blade body has a first cutting surface and a second cutting surface; A through hole is arranged in the center of the blade body for clamping with the cutting tool; The cutting edge is formed by the intersection of the first cutting edge and the second cutting edge; The feature is that the first and second cutting faces are provided with chip removal groove structures along the cutting edge direction. These chip removal groove structures are used to achieve chip curling or chip breaking under conditions of cutting depth ap = 0.05mm-0.30mm and feed rate f = 0.02-0.10mm / rev. The chip removal groove structure includes: At least a first and a second convex ridge have a wavy plurality of convex ridges extending laterally along at least 60% of the cutting edge length, with a peak-valley height h1 of 0.02 mm to 0.15 mm; The first chip removal groove is located between the first convex ridge and the cutting edge, with a groove bottom rake angle of +5° to +10°. A second chip removal groove is located between the first and second protruding edges and the cutting edge, with a bottom rake angle of −5°-0°. The second chip removal groove and the first chip removal groove form a stepped tool face. The induced protrusion, which is set in the tip region and is in the shape of a triangular pyramid, has a maximum height h2 that satisfies the condition 1.1h1≤h2≤1.5h1 on the first cutting surface.

2. The indexable insert according to claim 1, characterized in that The pitch between adjacent peaks of the first convex ridge is 0.20mm-0.50mm.

3. The indexable insert according to claim 1, wherein The apex of the induced protrusion points in the cutting feed direction, and the angle between it and the cutting edge is 30°-60°.

4. The indexable insert according to claim 1, characterized in that The bottom width of the first chip removal groove is 0.10mm-0.30mm.

5. The indexable insert according to claim 1, wherein The main body of the blade is made of WCCo cemented carbide, and the first blade surface is covered with a 1µm-3µm thick TiAlN-based nano-multilayer PVD coating.

6. The indexable insert according to claim 1, wherein The back angle of the blade is 7°-11°.

7. The indexable insert according to claim 1, wherein The peak height of the protruding ridge gradually decreases along the cutting edge direction.

8. An indexable insert according to any one of claims 1-7, characterized in that The blade has an 80° or 55° rhomboid shape and can be interchanged with ISO standard tool holders.

9. An indexable insert according to any one of claims 1-7, characterized in that The indexable insert is used for precision machining of stainless steel, aluminum alloy, or high-temperature alloys with small depth of cut.

10. A tool assembly characterized by, It includes a tool holder and an indexable insert as described in any one of claims 1-7 mounted on the tool holder.

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