A structurally reinforced round milling insert

Abstract

The utility model provides a kind of structure reinforced circular milling cutter piece, including two end faces and the side surface of connecting two end faces, the center of the blade has mounting hole, the intersection of at least one end face and side surface is cutting edge, the cutting edge is divided into multiple cutting units;The blade band is provided at the transition of the cutting edge and the end face, the width of each cutting unit blade band gradually decreases from the lowest of cutting unit to both sides;Negative chamfer is set, the included angle α of negative chamfer and base surface is variable angle included angle, the included angle β of rake face and base surface is variable angle included angle, from the lowest of cutting unit to both sides direction, included angle α and β gradually increase;The above design makes cutting edge most blunt at the lowest of cutting unit, maximum strength, from the lowest of cutting unit to both sides, cutting edge is more and more sharp, strength gradually decreases.The cutting edge is wavy shape, makes cutting edge length longer, has stronger cutting share capacity, enhances the strength of cutting edge.

Description

Technical Field

[0001] This utility model relates to the field of machining tool technology, and more specifically, to a structurally reinforced circular milling insert. Background Technology

[0002] Milling inserts used in the machining industry have round end faces. The intersection of the end face and the side face forms the cutting edge, which is circular and divided into 4 to 8 cutting units. The number of units determines the number of uses. To enhance the structural strength of the cutting edge, technicians frequently modify the insert's structure. For example, adding a cutting edge band or reducing the rake angle can improve the cutting edge's structural strength. Generally, the cutting edge band of milling inserts is of equal width, and the rake angle is the same. Those skilled in the art know that a wider cutting edge band and a smaller rake angle result in higher cutting edge strength but also a blunter cutting edge; conversely, a narrower cutting edge band and a larger rake angle result in a sharper cutting edge but a decrease in strength. During design, technicians often struggle to achieve a reasonable balance between the sharpness and strength of the cutting tool. Harder materials require a blunter cutting edge, resulting in lower sharpness; softer materials require a sharper cutting edge, but this comes at the cost of lower structural strength. For example, aluminum alloys are relatively soft. When machining aluminum alloys, blades with a large rake angle, narrow cutting edge, or even no cutting edge are selected. These blades have good sharpness but low structural strength and are prone to chipping in high-temperature and high-speed machining environments.

[0003] Patent application number 200910263792.0, entitled "Three-Dimensional Groove Circular Milling Insert" (hereinafter referred to as Patent 1), describes an invention patent where the width of the first positive rake angle face gradually increases within the working range and transitions to the starting width of the first positive rake angle face of the next unit cutting edge at the end of the transition range. This description essentially designs a three-dimensional grooved circular milling insert with variable cutting width and variable rake angle. Similarly, patent application number 201220067171.2, entitled "A Circular Milling Insert" (hereinafter referred to as Patent 2), describes a utility model patent where the width of the cutting edge plane varies between 0.05mm and 0.4mm with the circumferential angle, and the rake angle γ varies between 10° and 30° with the circumferential angle. Like the previous patent, it also provides a circular milling insert with variable cutting width and variable rake angle. The designs of these two patents enable the insert to meet both sharpness and strength requirements.

[0004] While Patent 1 addresses the requirement of achieving both sharpness and strength in cutting inserts through a variable rake angle, it doesn't specify the exact degree of the rake angle. A rake angle that's too large results in an overly sharp cutting edge, prone to chipping; a rake angle that's too small results in an overly blunt cutting edge, leading to excessive cutting resistance. Patent 2 specifies the rake angle, ranging from 10° to 30°, with the width of the cutting edge varying from 0.05mm to 0.4mm. Firstly, regarding the range of the rake angle, when machining cast iron, which is relatively hard, inserts with a rake angle of 0° to 10° are generally used in this field. Inserts with a rake angle varying from 10° to 30° still have an overly sharp cutting edge when machining cast iron, easily leading to chipping. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a structurally reinforced circular milling cutter suitable for machining relatively hard materials such as cast iron and steel.

[0006] A reinforced circular milling insert includes two end faces and a side face connecting the two end faces. The insert has a mounting hole at its center. At least one intersection of the end face and the side face is a cutting edge, which is divided into multiple cutting units. A cutting edge band is provided at the transition between the cutting edge and the end face, and the width of the cutting edge band gradually decreases from the lowest point of the cutting unit towards both sides. A negative chamfer is also provided at the transition between the cutting edge and the side face, and the angle between the negative chamfer and the base surface is α. The angle α gradually increases from the lowest point of the cutting unit towards both sides.

[0007] This utility model discloses a structurally reinforced circular milling insert. A cutting edge band and a negative chamfer are respectively provided on both sides of the cutting edge, enhancing the structural strength of the insert. The variable-width cutting edge band and variable-angle negative chamfer allow the insert's sharpness to vary depending on the machining depth, making it suitable for harder materials such as cast iron and steel. The cutting edge band and negative chamfer are respectively provided on both sides of the cutting edge. The negative chamfer is a chamfered surface inclined to the side, increasing the contact area between the tool and the workpiece. In actual machining, the cutting thickness of the circular tool gradually increases. At the beginning of cutting, the tool experiences a large cutting force in the depth direction. To prevent chipping, high edge strength is required. Therefore, this application has the thickest and strongest edge at the lowest point of the cutting unit. As milling progresses, the cutting depth increases, and the cutting force in the width direction gradually increases. The chip force in the width direction also increases, but the cutting force is smaller than that in the depth direction, and the cutting force in the width direction gradually increases with depth. To ensure both blade strength and sharpness for smoother cutting, and considering the actual variations in cutting force described above, the cutting edge is designed with a variable width and the negative chamfer with a variable angle to achieve both sharpness and high strength. Specifically, the cutting edge is widest at the point where the cutting unit first contacts the workpiece (the lowest point of the cutting unit), and the angle between the negative chamfer and the base surface is smallest, giving the cutting edge high strength and preventing chipping. On both sides of the lowest point of the cutting unit, the width of the cutting edge gradually decreases, and the angle between the negative chamfer and the base surface gradually increases, gradually decreasing the cutting edge strength and increasing sharpness for smoother cutting.

[0008] The two end faces described in this utility model are an upper end face and a lower end face, and cutting edges can be set on the upper end face and the lower end face respectively to improve economic efficiency. Some milling inserts also only have a cutting edge on one end face. The statement that at least one end face intersects with the side face as a cutting edge means that one end face has a cutting edge or both end faces have cutting edges.

[0009] The base surface refers to the surface perpendicular to the center line of the mounting hole.

[0010] The lowest point of the cutting unit refers to the following: when the blade is installed on the cutter head, a cutting unit extends from the cutter head, and the cutting edge is arc-shaped. At this time, the lowest position of the arc is the lowest point of the cutting unit, and the lowest point of the cutting unit contacts the workpiece first.

[0011] Furthermore, the angle of the negative chamfer varies within the range of 5° to 15°. Specifically, the angle of the negative chamfer from the starting position of the cutting unit to the lowest point of the cutting unit gradually decreases from 15° to 5°, and then the angle from the lowest point of the cutting unit to the ending position of the cutting unit gradually increases from 5° to 15°.

[0012] Furthermore, the cutting unit includes wave-shaped cutting edges, with smooth transitions between each pair of wave-shaped cutting edges; multiple wave-shaped cutting edges are connected sequentially to form a wave-shaped cutting edge. The wave-shaped cutting edge makes the cutting edge longer, has a stronger cutting force distribution capacity, and is more durable.

[0013] Furthermore, the length of the wave-shaped cutting edge is greater than the actual arc length used by the cutting unit, and the number of wave-shaped cutting edges is equal to the number of cutting units. The trough of the wave-shaped cutting edge is located at the lowest point of the cutting unit, and the waveform gradually rises from the lowest point of the cutting unit towards both sides. The function of the wave-shaped cutting edge is to make the cutting edge longer and have a stronger cutting load-sharing capability. The more wave-shaped cutting edges, the better, and the number of wave-shaped cutting edges can be greater than the number of cutting units. However, in order to ensure that the new cutting unit is completely new when the insert is indexed, one wave-shaped cutting edge is provided in each cutting unit, and the length of the wave-shaped cutting edge is greater than the actual arc length used by the cutting unit to ensure machining quality.

[0014] Furthermore, the number of cutting units on the end face is 6, and the number of wave-shaped blades is also 6.

[0015] Furthermore, the end face also has a rake face, located on the side of the cutting edge facing the mounting hole; the angle between the rake face and the base surface is the rake angle β, which gradually increases from the lowest point of the cutting unit towards both sides. The rake angle, combined with the changing pattern of the cutting edge and negative chamfer (at the lowest point of the cutting unit, the cutting edge is blunter and stronger; towards both sides from the lowest point of the cutting unit, the cutting edge becomes increasingly sharper and weaker), corresponds to the following: at the lowest point of the cutting unit, the rake angle is smallest, the cutting edge is most blunt, and the strength is greatest; towards both sides from the lowest point of the cutting unit, the rake angle increases, the cutting edge becomes increasingly sharper, and the strength decreases, which meets the needs of practical use.

[0016] Furthermore, the rake angle varies within the range of 3° to 10°. Specifically, the rake angle gradually decreases from 10° to 3° from the starting position of the cutting unit to the lowest point of the cutting unit, and then increases from 3° to 10° from the lowest point of the cutting unit to the ending position of the cutting unit.

[0017] When machining cast iron, inserts with a rake angle of 0–10° are generally selected; when machining steel, inserts with a rake angle of 5°–15° are generally selected. The reinforced circular milling insert described in this invention is suitable for harder materials such as cast iron and steel, therefore the rake angle β varies within the range of 3°–10°. When cutting softer materials, a sharper insert is required; for example, when machining aluminum, a cutting edge may not even be necessary. This application features a cutting edge and negative chamfer, thus making it suitable for harder materials such as cast iron and steel.

[0018] Furthermore, the two end faces of the structurally reinforced circular milling cutter have the same structure. That is, the structurally reinforced circular milling cutter is a double-sided circular milling cutter, with cutting edges at both ends, which increases economic efficiency.

[0019] Furthermore, an anti-rotation positioning groove is provided on the end face. This anti-rotation positioning groove is radially arranged around the central axis of the mounting hole. The number of anti-rotation positioning grooves equals the number of cutting units. Each anti-rotation positioning groove is located at the intersection of two cutting units. When the insert is installed on the cutter head, a fastener is used through the mounting hole to axially position the insert. Correspondingly, the insert mounting area on the cutter head also has protrusions adapted to the anti-rotation positioning grooves. The number and position of these protrusions are the same as the anti-rotation positioning grooves, and the protrusions provide radial positioning for the insert. When the insert is rotated, it is rotated to re-engage with the protrusion. The anti-rotation positioning groove is located at the intersection of two cutting units, and there is a cutting unit between each pair of anti-rotation positioning grooves, extending from the cutter head.

[0020] Furthermore, the side surface is provided with anti-rotation positioning grooves II, the number of which is equal to the number of cutting units; the anti-rotation positioning grooves II are opened at the intersection of two cutting units.

[0021] This utility model has the following beneficial effects:

[0022] This utility model discloses a structurally reinforced circular milling insert. By adding a cutting edge and a negative chamfer, and designing the shape and angle of the cutting edge, negative chamfer, cutting edge, and rake angle, the structural strength of the insert's cutting edge is maximized and its sharpness is improved. This utility model combines high strength and sharpness, making it suitable for hard materials such as cast iron and steel. Specifically: 1. Adding a cutting edge and designing it as a variable-width structure; 2. Adding a negative chamfer and designing it as a variable-angle structure; 3. Designing the angle between the rake face and the base plane as a variable angle; 4. Designing the cutting edge as a wavy shape. The design of points 1 to 3 ensures that the cutting edge is bluntest and strongest at the lowest point of the cutting unit, gradually becoming sharper and weaker towards both sides. The design of point 4 extends the cutting edge length, providing stronger cutting load distribution and enhancing the strength of the cutting edge. Attached Figure Description

[0023] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0024] Figure 1 This is a schematic diagram of a reinforced circular milling cutter structure according to Example 1;

[0025] Figure 2 This is a schematic diagram of a reinforced circular milling cutter mounted on a cutter head, as shown in Example 1.

[0026] Figure 3 This is a schematic diagram of a reinforced circular milling cutter structure in Example 3;

[0027] Figure 4 This is a schematic diagram of a reinforced circular milling cutter mounted on a cutter head, as shown in Example 3.

[0028] The serial numbers are: 1-end face, 2-side face, 3-cutting unit, 4-cutting edge, 5-rake face, 6-anti-rotation positioning groove one, 7-anti-rotation positioning groove two, 8-mounting hole, insert-D. Detailed Implementation

[0029] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered by the claims.

[0030] Furthermore, it should be understood in the description of this application that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0031] Example 1

[0032] A structurally reinforced circular milling insert, such as Figure 1 As shown, the blade includes two end faces 1 and a side surface 2 connecting the two end faces 1. The blade has a mounting hole 8 at its center. The intersection of the two end faces 1 and the side surface 2 forms the cutting edge, which is divided into multiple cutting units 3. Figure 1 As shown, the circular milling cutter in this embodiment is cylindrical, and both ends 1 of the cylindrical milling cutter have cutting edges. The cutting edges are divided into 6 cutting units 3, and there are a total of 12 cutting units 3 on the two sides. It can be used 12 times, which has good economic efficiency.

[0033] A cutting edge band 4 is provided at the transition point between the cutting edge and the end face 1, such as... Figure 1 As shown, the width of the cutting edge 4 in each cutting unit 3 gradually decreases from the lowest point of the cutting unit 3 towards both sides. The cutting edge 4 is thickest at the lowest point of each cutting unit 3, and its width gradually decreases towards both sides. This variable cutting width structure makes the cutting edge 4 thicker in the middle and gradually thinner at the edges, giving the insert both good strength and the required sharpness for easy cutting. In this embodiment, to enhance the strength of the cutting edge, not only is the cutting edge 4 improved, but a negative chamfer is also added and designed as a variable angle structure. The angle between the rake face 5 and the base surface is also designed as a variable angle. The variable cutting width, variable angle negative chamfer, and variable rake angle are all designed to make each cutting unit 3 thicker in the middle and gradually thinner towards the sides, resulting in greater strength in the middle part of the cutting unit 3 and gradually decreasing strength towards the sides while increasing sharpness. This conforms to actual machining conditions, giving the insert both high strength and a certain level of sharpness. Specifically:

[0034] A negative chamfer (not shown in the figure) is also provided at the transition between the cutting edge and the side surface 2. The angle between the negative chamfer and the base surface is α. The angle α gradually increases from the lowest point of the cutting unit 3 to both sides.

[0035] The angle of the negative chamfer varies within the range of 5° to 15°. Specifically, the angle of the negative chamfer from the starting position of the cutting unit 3 to the lowest point of the cutting unit 3 gradually decreases from 15° to 5°, and then the angle from the lowest point of the cutting unit 3 to the ending position of the cutting unit 3 gradually increases from 5° to 15°.

[0036] The end face 1 also has a rake face 5, which is located on the side of the cutting edge 4 facing the mounting hole 8. The angle between the rake face 5 and the base surface is the rake angle β, which gradually increases from the lowest point of the cutting unit 3 towards both sides. The rake angle corresponds to the variation law of the width of the cutting edge 4 and the angle of the negative chamfer (at the lowest point of the cutting unit 3, the cutting edge is blunter and the strength is greater; from the lowest point of the cutting unit 3 towards both sides, the cutting edge becomes sharper and the strength decreases). At the lowest point of the cutting unit 3, the rake angle is the smallest, the cutting edge is the bluntest, and the strength is the greatest; from the lowest point of the cutting unit 3 towards both sides, the rake angle becomes larger, the cutting edge becomes sharper, and the strength decreases, which meets the needs of actual use.

[0037] The rake angle varies within the range of 3° to 10°. Specifically, the rake angle gradually decreases from 10° to 3° from the starting position of the cutting unit 3 to the lowest point of the cutting unit 3, and then increases from 3° to 10° from the lowest point of the cutting unit 3 to the ending position of the cutting unit 3.

[0038] When the material to be machined is cast iron, inserts with a rake angle of 0 to 10° are generally selected; when the material to be machined is steel, inserts with a rake angle of 5° to 15° are generally selected. The structurally reinforced circular milling insert of this utility model is suitable for hard materials such as cast iron and steel, so the rake angle β varies in the range of 3° to 10°.

[0039] like Figure 1 As shown, an anti-rotation positioning groove 6 is also provided on the end face 1. The anti-rotation positioning groove 6 is arranged radially around the central axis of the mounting hole 8. The number of anti-rotation positioning grooves 6 is equal to the number of cutting units 3. In this embodiment, there are six cutting units 3 on one end face 1, so the number of anti-rotation positioning grooves 6 is also six. The anti-rotation positioning groove 6 is opened at the intersection of two cutting units 3. Figure 2 As shown, when the blade is installed on the cutter head, a fastener is used to pass through the mounting hole 8 to axially position the blade. Correspondingly, the blade mounting area of ​​the cutter head is also provided with protrusions that match the anti-rotation positioning grooves. The number and position of the protrusions correspond to the anti-rotation positioning grooves, and the protrusions provide radial positioning for the blade. When the blade is rotated, it is simply rotated to re-engage with the protrusion. The anti-rotation positioning grooves are located at the intersection of two pairs of cutting units 3, with one cutting unit 3 between each pair of anti-rotation positioning grooves. The cutting unit 3 extends from the cutter head.

[0040] Example 2

[0041] The difference between Example 2 and Example 1 is that, based on the blade structure described in Example 1, the strength of the cutting edge is further enhanced. The cutting unit 3 includes wave-shaped blades, with smooth transitions between each pair of wave-shaped blades; multiple wave-shaped blades are connected sequentially to form a wave-shaped cutting edge. The wave-shaped cutting edge makes the cutting edge longer, has a stronger cutting force distribution capacity, and is more durable.

[0042] like Figure 1 As shown, the length of the wave-shaped cutting edge is greater than the actual arc length used by the cutting unit 3, and the number of wave-shaped cutting edges is equal to the number of cutting units 3. The trough of the wave-shaped cutting edge is located at the lowest point of the cutting unit 3, and the waveform gradually rises from the lowest point of the cutting unit 3 towards both sides. The function of the wave-shaped cutting edge is to make the cutting edge longer and have a stronger cutting load-sharing capability. The more wave-shaped cutting edges, the better, and the number of wave-shaped cutting edges can be greater than the number of cutting units 3. However, in order to ensure that the new cutting unit 3 is brand new when the insert is indexed, one wave-shaped cutting edge is provided in one cutting unit 3, and the length of the wave-shaped cutting edge is greater than the actual arc length used by the cutting unit 3 to ensure machining quality. The number of cutting units 3 on the end face 1 is 6, and the number of wave-shaped cutting edges is also 6.

[0043] Example 3

[0044] The difference between Embodiment 3 and Embodiment 2 lies in the position of the anti-rotation positioning groove of the blade. In Embodiment 2, the anti-rotation positioning groove is located on the end face 1 of the blade, while in this embodiment, the anti-rotation positioning groove is located on the side 2 of the blade. Figure 3 and Figure 4 As shown, the side 2 is provided with anti-rotation positioning groove 2 7, and the number of anti-rotation positioning groove 2 7 is equal to the number of cutting units 3; the anti-rotation positioning groove 2 7 is opened at the intersection of two cutting units 3.

[0045] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Various modifications and variations can be made to the present utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the scope of the present utility model.

Claims

1. A reinforced circular milling insert, comprising two end faces and a side face connecting the two end faces, wherein the insert has a mounting hole at its center, and at least one intersection of the end face and the side face is a cutting edge, the cutting edge being evenly divided into multiple cutting units; characterized in that, A cutting edge band is provided at the transition between the cutting edge and the end face. The width of the cutting edge band gradually decreases from the lowest point of the cutting unit to both sides. A negative chamfer is also provided at the transition between the cutting edge and the side face. The angle between the negative chamfer and the base surface is α. The angle α gradually increases from the lowest point of the cutting unit to both sides.

2. The reinforced circular milling cutter according to claim 1, characterized in that, The cutting unit includes wave-shaped cutting edges, with smooth transitions between each pair of wave-shaped cutting edges; multiple wave-shaped cutting edges are connected in sequence to form a wave-shaped cutting edge.

3. A reinforced circular milling cutter according to claim 2, characterized in that, The length of the wave-shaped blade is greater than the actual arc length used by the cutting unit, and the number of wave-shaped blades is equal to the number of cutting units; the trough of the wave-shaped blade is located at the lowest point of the cutting unit, and the waveform gradually rises from the lowest point of the cutting unit to both sides.

4. A reinforced circular milling cutter according to claim 3, characterized in that, The number of cutting units on the end face is 6, and the number of wave-shaped blades is also 6.

5. A structurally reinforced circular milling cutter according to claim 2, characterized in that, The end face also has a rake face, which is located on the side of the cutting edge facing the mounting hole; the angle between the rake face and the base surface is the rake angle β, which gradually increases from the lowest point of the cutting unit to both sides.

6. A reinforced circular milling cutter according to claim 5, characterized in that, The rake angle varies within the range of 3° to 10°. Specifically, the rake angle gradually decreases from 10° to 3° from the starting position of the cutting unit to the lowest point of the cutting unit, and then increases from 3° to 10° from the lowest point of the cutting unit to the ending position of the cutting unit.

7. A structurally reinforced circular milling cutter according to claim 6, characterized in that, The two end faces of the reinforced circular milling cutter have the same structure.

8. A reinforced circular milling cutter according to claim 1, characterized in that, An anti-rotation positioning groove is also provided on the end face. The anti-rotation positioning groove is arranged radially around the mounting hole with the central axis of the mounting hole as the axis. The number of anti-rotation positioning grooves is equal to the number of cutting units. The anti-rotation positioning groove is opened at the intersection of two cutting units.

9. A structurally reinforced circular milling cutter according to claim 1, characterized in that, The side is provided with a second anti-rotation positioning groove, the number of which is equal to the number of the cutting units; the second anti-rotation positioning groove is opened at the intersection of two cutting units.

10. A structurally reinforced circular milling cutter according to claim 1, characterized in that, The angle of the negative chamfer varies within the range of 5° to 15°. Specifically, the angle of the negative chamfer gradually decreases from 15° to 5° from the starting position of the cutting unit to the lowest point of the cutting unit, and then gradually increases from 5° to 15° from the lowest point of the cutting unit to the ending position of the cutting unit.

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