CN217749517U - Forming milling cutter suitable for scroll plate - Google Patents

Abstract

The utility model relates to a formed milling cutter suitable for a scroll, which comprises a cutter main body, wherein the cutter main body is sequentially provided with a first cutter part and a second cutter part along a first direction of the axis of the milling cutter, and the first cutter part and the second cutter part are in a ladder shape; at least two rows of chip grooves are formed in the periphery of the cutter main body, and the chip grooves extend from the end face of the first cutter part to the second cutter part; the chip discharge groove is formed with a first peripheral edge and a second peripheral edge on the first cutter part and the second cutter part, respectively, and the diameter of the second peripheral edge is larger than that of the first peripheral edge. Through different parts on the first peripheral edge and the second peripheral edge forming scroll plate, the tool changing and positioning steps are simplified, and the processing precision is improved.

Description

Forming milling cutter suitable for scroll plate

Technical Field

The utility model relates to a milling process field especially relates to a shaping milling cutter suitable for vortex dish.

Background

The aluminum alloy scroll plate is used as a core component of a scroll compressor in a new energy automobile, and the processing precision of the aluminum alloy scroll plate directly influences the working performance of the scroll compressor. The scroll is a typical thin-wall part, and the scroll comprises a complex scroll profile and a chamfer structure, so that the difficulty of the cutter cutting manufacturing process is increased. Specifically, the forming chamfer is different from the tools required to form other parts, so that the tools need to be replaced in the forming chamfer structure, and higher precision is required in the forming process. Need reposition the cutter after changing the cutter, it is high to guarantee the accurate location requirement of shaping position.

SUMMERY OF THE UTILITY MODEL

Accordingly, it is necessary to provide a milling cutter suitable for a scroll in order to solve the problem that positioning accuracy is difficult to ensure after replacement of a tool.

The application provides a formed milling cutter suitable for a scroll, which comprises a cutter body, wherein the cutter body is sequentially provided with a first cutter part and a second cutter part along a first direction of the axis of the milling cutter, and the first cutter part and the second cutter part are in a step shape;

at least two rows of chip grooves are formed in the periphery of the cutter main body, and the chip grooves extend from the end face of the first cutter part to the second cutter part; the chip groove is provided with a first peripheral edge and a second peripheral edge on the first cutter part and the second cutter part respectively, and the diameter of the second peripheral edge is larger than that of the first peripheral edge.

According to the technical scheme of the embodiment of the application, the first cutter part and the second cutter part are arranged in a ladder shape, and the protruding second cutter part is convenient for forming chamfers, so that the first cutter part forms chamfers on the two cutter parts while forming the hole groove, and the first cutter part and the second cutter part are relatively fixed in the forming process, so that the precision can be ensured, and the positioning step can be omitted.

In one embodiment, a transition slope is arranged at the joint of the first cutter part and the second cutter part, and comprises a slope extending from the back surface of the first peripheral cutter to the back surface of the second peripheral cutter; the inclined plane gradually deviates away from the axis of the milling cutter along a first direction;

the tool back surfaces of the first and second peripheral edges are surfaces formed by intersecting the chip discharge grooves with the peripheries of the corresponding first and second tool parts.

In one embodiment, the inclined planes comprise a first inclined plane and a second inclined plane which are sequentially arranged along the first direction, and the included angle formed by the first inclined plane and the back surface of the first peripheral knife is smaller than the included angle formed by the second inclined plane and the back surface of the second peripheral knife.

In one embodiment, the flute intersects the slope of the transition ramp to form a minor end edge.

In one embodiment, the flute intersects an end surface of the first cutter portion that intersects the first direction to form a major end edge.

In one embodiment, a chamfer is arranged at an included angle formed by the intersection of the main end edge and the knife back surface of the first peripheral edge, the other side of the main end edge corresponding to the chamfer is a tail end, the tail end is close to the axle center of the first knife part, and the tail ends of the main end edges do not intersect.

In one embodiment, the cutting edge of the main end edge is gradually offset from the distal end towards the chamfer to a side away from the axis of the milling cutter.

In one embodiment, the flute comprises a rake face that intersects the major end edge to form an end edge.

In one embodiment, the second tool part has a shank at one end, the first tool part, the second tool part and the shank are arranged in sequence along the first direction, and the diameter of the shank is not smaller than that of the second peripheral edge.

In one embodiment, the zirconium nitride coating is arranged on the aluminum alloy base layer of the first cutter part and the second cutter part.

Drawings

Fig. 1 is a front view of a milling cutter according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a part of a milling cutter according to an embodiment of the present invention;

FIG. 3 is an enlarged partial view of a cross-section taken at A in FIG. 2;

fig. 4 is a schematic structural view of an upper end blade of a milling cutter according to an embodiment of the present invention;

fig. 5 is a left side view of a milling cutter according to an embodiment of the present invention.

Reference numerals:

11. a first cutter portion;

111. a first peripheral edge; 112. a main end edge; 113. chamfering;

1121. a terminal end;

12. a second cutter portion;

121. a second peripheral edge;

1211. a first inclined plane; 1212. a second inclined plane;

13. a chip groove;

131. the bottom surface of the groove; 132. a knife face is formed; 133. entering a cutter face; 134. an end blade edge;

14. an end face;

15. a handle portion.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will be able to make similar modifications without departing from the spirit and scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrated; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present application, unless expressly stated or limited otherwise, the first feature may be directly on or directly under the second feature or indirectly via intermediate members. Also, a first feature "on," "above," and "over" a second feature may be directly on or obliquely above the second feature, or simply mean that the first feature is at a higher level than the second feature. A first feature "under," "beneath," and "under" a second feature may be directly under or obliquely under the second feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Referring to fig. 1 and 2, fig. 1 is a front view of a milling cutter according to some embodiments of the present application, and fig. 2 is a schematic structural view of a portion of the milling cutter according to some embodiments of the present application. The application provides a formed milling cutter suitable for a scroll, which comprises a cutter body, wherein the cutter body is sequentially provided with a first cutter part 11 and a second cutter part 12 along a first direction of the axis of the milling cutter, and the first cutter part 11 and the second cutter part 12 are in a step shape;

at least two chip grooves 13 are arranged on the periphery of the cutter main body, and the chip grooves 13 extend from the end surface 14 of the first cutter part 11 to the second cutter part 12; the chip grooves 13 form first and second peripheral edges 111 and 121 on the first and second tool parts 11 and 12, respectively, and the diameter of the second peripheral edge 121 is larger than that of the first peripheral edge 111.

Specifically, the first tool part 11 and the second tool part 12 are stepped, and the outer diameter of the second tool part 12 is larger than that of the first tool part, so that a step is formed on the end surface of the second tool part 12. At the same time, the same chip flute 13 extends from the end face 14 through the first tool part 11 and onto the second tool part 12. The first and second peripheral edges 111 and 121 are formed at corresponding positions on the first and second tool parts 11 and 12 by the chip flutes 13. And the diameter of the first tool part 11 is the diameter of the second tool part 12 itself, the back of the first and second peripheral edges 111 and 121 is formed by the outer peripheries of the first and second tool parts 11 and 12, so that the maximum profile of the first and second peripheral edges 111 and 121 is determined by the outer peripheries of the first and second tool parts 11 and 12. Finally, the diameter of the second peripheral edge 121 is larger than the diameter of the first peripheral edge 111.

The first peripheral edge 111 and the second peripheral edge 121 are spirally convex edges formed by the outer peripheries of the first peripheral edge 111 and the second peripheral edge 121 between the adjacent two chip grooves 13 and the chip grooves 13, and the first peripheral edge 111 and the second peripheral edge 121 are provided around the tool side. The chip groove 13 intersects with the outer peripheral side surfaces of the first and second peripheral edges 111, 121 to form a back surface of the first and second peripheral edges 111, 121. The chip groove 13 divides the periphery of the cutter into a plurality of convex spiral peripheral edges, and the surface of the peripheral edge, which is located on the original peripheral side surface, is the cutter back surface.

First, the chip flutes 13 of the first tool part 11 and the second tool part 12 have the same shape, the same rotational direction, and the same helix angle, and the helix angle of the chip flutes 13 ranges from 32 ° to 35 °. The uniformity of the chip grooves 13 on the first cutter part 11 and the second cutter part 12 is ensured, and the phenomenon that the chip grooves 13 are too narrow at the connecting part of the first cutter part 11 and the second cutter part 12 to influence the smoothness of chip outflow is avoided. More importantly, different positions can be conveniently and simultaneously cut through the stepped cutter body. Particularly, in the process of processing the inner chamfer, the position of the inner chamfer and the position of the formed hole groove are relatively fixed, when two cutters are used for processing, positioning operation needs to be carried out after the cutters are replaced, the positioning accuracy is required to be high, and the problem that the position of the inner chamfer does not correspond to the hole groove easily occurs or not, but in the application, the first cutter part 11 and the second cutter part 12 which are arranged in a ladder way are used for facilitating the processing of the inner chamfer by the second cutter part 12 while the hole groove is formed by the first cutter part 11, and the second cutter part 12 are coaxially arranged, so that the problem of dislocation is avoided in the forming process because the position relation between the first cutter part 11 and the second cutter part 12 is fixed. The side wall and the forming chamfer angle of the workpiece can be efficiently processed, and the processing accuracy and consistency are ensured.

Referring to fig. 2 and 3, fig. 3 is a partially enlarged schematic view of a cross-section at a on fig. 2 according to some embodiments of the present application. A transition slope is arranged at the connection position of the first cutter part 11 and the second cutter part 12, and comprises an inclined plane extending from the back surface of the first peripheral knife 111 to the back surface of the second peripheral knife 121; the bevel is offset progressively away from the mill axis in a first direction.

The transition slope is ground by the first peripheral blade 111 to the second cutter portion 12 in the first direction so that the outer edge of the first peripheral blade 111 smoothly transitions to the second cutter portion 12. The transition slope includes a slope surface connecting the back surfaces of the first peripheral blade 111 and the second peripheral blade 121. The back surfaces of the first and second peripheral blades 111 and 121 are the peripheral side walls of the first and second cutter portions 11 and 12, respectively, due to the diameter d of the second peripheral blade 121 ₂ Is larger than the diameter d of the first peripheral blade 111 ₁ Thus, the inclined surface connecting the back surfaces of the first and second peripheral blades 111 and 121 is a plane or an arc surface offset from the first direction. In particular, d ₁ Range of (1)8 mm-10 mm.

Further, buffer margins are provided at the circumferential cutting edges of the first cutter portion 11 and the second cutter portion 12, and the buffer margins are used for protecting the circumferential cutting edges. The thickness range of the buffer blade is 0.03 mm-0.06 mm, and the back angle of the buffer blade is 2-3 degrees. The buffer storage blade edge is arranged to protect the circumferential cutting edge, so that the service life of the cutter is prolonged.

The flank surfaces of the first peripheral cutting edge 111 and the second peripheral cutting edge 121 are straight flank surfaces, and the aluminum alloy has a small elastic modulus, so that a workpiece is prone to generate large elastic deformation during cutting, and high-quality machining precision is difficult to obtain. Meanwhile, the machining tool also causes severe friction between a rear cutter face and a machined surface, so that the abrasion of the tool is increased and vibration is caused, and the machining tool is particularly obvious in the machining of thin-walled parts such as a scroll. The first peripheral edge knives 111 and the second peripheral edge knives 121 have a first back angle of 10-14 degrees and a second back angle of 20-25 degrees. To increase the clearance between the cutting tool and the machined surface, reduce wear and heat generated by friction of the circumferential edge of the tool with the aluminum alloy material and reduce heat generated by friction.

According to some embodiments of the present application, further, the flute 13 intersects with the slope of the transition slope to form a secondary end edge as a tertiary cutting edge.

The flute 13 and the inclined surface of the transition slope intersect to form a secondary end edge with a cutting direction different from that of the first and second peripheral knives 111 and 121, so that the secondary end edge is formed into a more complex structure. The strength of the connecting position of the first cutter part 11 and the second cutter part 12 can be effectively improved by arranging the transition slope, and the transition slope forms a third cutting edge between the first cutter part 11 and the second cutter part 12, so that the area of the cutting edge is increased, and the cutting efficiency is improved.

According to some embodiments of the present application, the inclined surfaces include a first inclined surface 1211 and a second inclined surface 1212 sequentially arranged along the first direction, and an included angle formed by the first inclined surface 1211 and the back surface of the first peripheral edge 111 is smaller than an included angle formed by the second inclined surface 1212 and the back surface of the second peripheral edge 121.

The first inclined surface 1211 is formed with the back surface of the first peripheral edge 111Angle delta of ₁ The angle δ formed by the second inclined plane 1212 and the back surface of the second peripheral edge 121 ₂ Wherein δ is satisfied ₁ <δ ₂ . In particular, delta ₁ The included angle is the included angle formed by the intersection of the first inclined surface 1211 and the straight line of the knife back at the section of the first peripheral edge 111. Delta. For the preparation of a coating ₂ The included angle is the included angle formed by the intersection of the second inclined surface 1212 and the straight line of the back of the knife at the section of the second peripheral edge 121.

The first inclined surface 1211 and the second inclined surface 1212 having different inclination degrees facilitate forming different types of chamfer structures. Or the first inclined surface 1211 and the second inclined surface 1212 have different inclination degrees, so that the cutting amount of the first inclined surface 1211 and the second inclined surface 1212 is different, and the single cutting amount can be reduced by the cooperation of the first inclined surface 1211 and the second inclined surface 1212, thereby protecting the secondary end edge and prolonging the service life of the tool.

According to some embodiments of the present application, the flute 13 intersects the end surface 14 of the first tool part 11 intersecting the first direction to form a main end edge 112. The end face 14 is located at the start and end in the first direction of the milling cutter, and specifically, the end face 14 is preferentially brought into contact with the cutting material at the time of cutting.

The flute 13 intersects one end of the first peripheral edge 111 at the end face 14 to form a main end edge 112. The major end edge 112 serves as a portion which first contacts the cutting material to form the bottom. In this embodiment, the end of the main end blade 112 away from the axial center is in contact with the cutting material to cut the material. The first peripheral edge 111 is used for cutting and forming the side wall, and the main end edge 112 is used for forming the bottom surface, so that the surface finish of the workpiece is improved, and the cutting efficiency is improved.

In particular, referring to fig. 4 and 5, fig. 4 is a schematic view of a structure of an upper end edge of a milling cutter according to some embodiments of the present application, and fig. 5 is a left side view of the milling cutter according to some embodiments of the present application. The number of the chip flutes 13 is four, four first peripheral edges 111 are formed by the four chip flutes 13, and each first peripheral edge 111 is located on the end surface 14 to form a main end edge 112. The chip grooves 13 are distributed unequally relative to the circumference of the cutter. So that the included angle between at least two adjacent first circumferential edges 111 is different, that is, θ 1 is not equal to θ 2, and the angle difference is 3 to 6 degrees. The unequal-tooth-part first peripheral edge 111 is designed to generate alternating cutting frequency during high-speed cutting, is not easy to resonate with a machine tool, and effectively eliminates or avoids cutting chatter when the cutter is used for machining thin-walled parts.

According to some embodiments of the present application, specifically, a chamfer 113 is provided at an included angle formed by intersection of the main end edge 112 and the back surface of the first peripheral edge 111, the other side of the main end edge 112 corresponding to the chamfer 113 is an end 1121, the end 1121 is close to the axis of the first tool part 11, and the ends 1121 of the main end edge 112 do not intersect each other.

A vacant slot position is formed on the end surface 14 close to the axle center, so that the area of a chip groove of the end surface 14 is increased, and the chip-containing space for cutting the cutter is enlarged. The main end blade 112 and the cutting point where the back of the knife surface of the first peripheral blade 111 intersects are chamfered, and in the scheme, the intersected included angle is chamfered, so that stress concentration of the knife tip can be effectively eliminated or avoided, the strength of the cutting edge of the knife tip is improved, and the risk of breakage or plastic deformation abrasion of the knife tip tipping blade is reduced.

According to some embodiments of the present application, the cutting edge of the main end edge 112 is gradually offset to a side away from the axis of the first cutter portion 11 from the end 1121 toward the chamfer 113.

The cutting edge of the main end edge 112 is recessed toward the axial center, and the angle of concavity of the cutting edge of the main end edge 112 is 3.5 degrees to reduce the contact area between the cutting edge of the main end edge 112 and the material, thereby increasing the cutting force of the main end edge 112 and making the main end edge 112 sharper. On the other hand, the cutting edge of the main end edge 112 is inwardly concave, so that an inwardly concave space is formed on the end face 14, in order to further enlarge the tool cutting chip space. The chip-holding capacity during cutting is improved, and the problems of low machining precision and poor surface roughness caused by unsmooth chip removal can be avoided.

According to some embodiments of the present application, as shown in FIG. 4. Flute 13 includes a rake face 133, the rake face 133 intersecting the major end edge 112 to form an end edge 134.

The chip groove 13 includes a chip-entering surface 133, a groove bottom surface 131, and a chip-discharging surface 132. The rake face 132 and the rake face 133 are provided on both sides of the groove bottom face 131, respectively, so that the rake face 133 and the main end blade 112 form an end blade edge 134 as a cutting edge. The rake face 132 forms the back land of the main end edge 112. The knife entering face 133 is inclined relative to the tangent line of the connecting point with the groove bottom face 131, so as to adjust the included angle formed by the knife entering face 133 where the end edge 134 is located and the main end edge 112, and adjust the size and the edge strength of the first peripheral edge 111 and the main end edge 112 on the first cutter portion 11, so as to improve the cutting performance of the milling cutter.

According to some embodiments of the present application, the second tool portion 12 is provided with a shank 15 at one end, the first tool portion 11, the second tool portion 12 and the shank 15 are arranged in sequence along a first direction, and the diameter of the shank 15 is not smaller than the diameter of the second peripheral edge 121.

The shank 15 is used for clamping and fixing a tool, and at the same time, the first tool part 11, the second tool part 12 and the shank 15 are coaxially arranged so that a centrifugal force generated by inertia when rotating the milling cutter is reduced, and the diameter of the shank 15 is greater than or equal to the diameter d of the second tool part 12 ₂ 。

According to some embodiments of the present application, a plurality of crystalline structure coatings are provided on a cutter on a milling cutter. Zirconium nitride coatings are arranged on the aluminum alloy base layers of the first cutter part 11 and the second cutter part 12.

The milling cutter is made of a high-hardness HRA (Rockwell hardness) ultrafine grain hard alloy bar material, and specifically, the milling cutter is made of an aluminum alloy. The aluminum alloy material contains silicon and cobalt, wherein the cobalt content is 9%. For the silicon-aluminum alloy, the Si-containing element can effectively improve the tensile strength, the hardness and the high-temperature strength of the material, but the hard points of free silicon are easy to appear at the same time, so that the machinability is poor, and particularly, the high-silicon aluminum alloy (Si is more than or equal to 12 percent) is more obvious. The aluminum alloy has a low melting point, the plasticity is increased after temperature rise, when chips flow out, under the action of high temperature and high pressure, the friction between a chip bottom layer and a front cutter surface is large, the retention phenomenon is serious, chip accretion is easy to generate, the processing precision of a workpiece is reduced, the surface roughness is poor, and the service life of a cutter is shortened. In the present embodiment, the peripheral edge rake angle is in the range of 9 ° to 12 °. The strength, the sharpness and the chip removal performance of the cutter are considered while the edge tipping and the damage of the cutting edge are prevented.

Specifically, the milling cutter is manufactured by grinding and selecting the ultra-fine abrasive diamond resin grinding wheel, and the fine polishing treatment is carried out on the front cutter face and the rear cutter face in the groove and the cutting edge of the milling cutter so as to reduce the friction coefficient between the cutting chips and the front cutter face and enable the chip removal to be smoother. Meanwhile, before the cutter coating, the cutting edge is subjected to round angle passivation through quartz sand blasting treatment, so that the grinding lines of the cutting edge are smooth, and the micro defects such as sawteeth are avoided.

After the passivation treatment, the surface of the cutter is subjected to zirconium nitride (ZrN) coating treatment by means of Physical Vapor Deposition (PVD). Zirconium nitride (ZrN) is a poorly soluble compound, is golden yellow, has a high decomposition temperature, good chemical stability, and has good high temperature resistance, corrosion resistance, and surface lubricity. The zirconium nitride (ZrN) coating can improve the surface hardness and comprehensive mechanical property of the cutter, effectively reduce the friction coefficient between chips and the front cutter surface of the cutter, prevent element affinity reaction between the cutter and a workpiece, and eliminate or avoid the bonding and diffusion abrasion of the cutting edge.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the concept of the present invention, several variations and modifications can be made, which all fall within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims (10)

1. The formed milling cutter suitable for the scroll is characterized by comprising a cutter body, wherein the cutter body is sequentially provided with a first cutter part and a second cutter part along a first direction of the axis of the milling cutter, and the first cutter part and the second cutter part are in a step shape;

at least two chip grooves are formed in the periphery of the cutter main body, and extend from the end face of the first cutter part to the second cutter part; the chip groove is provided with a first peripheral edge and a second peripheral edge on the first cutter part and the second cutter part respectively, and the diameter of the second peripheral edge is larger than that of the first peripheral edge.

2. The milling cutter according to claim 1, wherein a junction of the first cutter portion and the second cutter portion is provided with a transition ramp comprising a chamfer extending from the first peripheral shelf back face to the second peripheral shelf back face; the bevel is offset gradually away from the milling cutter axis in a first direction;

the tool back surfaces of the first and second peripheral edges are surfaces formed by intersecting the chip grooves and the peripheries of the corresponding first and second tool parts.

3. The milling cutter according to claim 2, wherein the chamfer includes a first chamfer and a second chamfer disposed in series along a first direction, the first chamfer forming a smaller included angle with the first peripheral edge back surface than the second chamfer forming a smaller included angle with the second peripheral edge back surface.

4. The milling cutter according to claim 2, wherein the intersection of the flute with the chamfer of the transition ramp forms a minor end edge.

5. The milling cutter according to claim 1, wherein the flutes intersect end surfaces on the first tool portion that intersect the first direction to form major end edges.

6. The milling cutter according to claim 5, wherein the main end edge intersects the back surface of the first peripheral edge to form a chamfer, the main end edge has a distal end on the other side thereof corresponding to the chamfer, the distal end is close to the axial center of the first tool portion, and the distal ends of the main end edges do not intersect with each other.

7. The milling cutter according to claim 6, wherein the edge of the major end edge is gradually offset to a side away from the milling cutter axis from the tip in a direction toward the chamfer.

8. The milling cutter according to claim 5, wherein the flute comprises a rake face that intersects the major end edge to form an end edge.

9. The milling cutter according to any one of claims 1 to 8, wherein the second tool part has a shank portion at one end, the first tool part, the second tool part and the shank portion being arranged in the first direction in this order, the shank portion having a diameter not smaller than the diameter of the second peripheral edge.

10. The milling cutter according to claim 9, wherein a zirconium nitride coating is provided on the aluminum alloy base layer of the first and second tool portions.

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