Patent ID: 12186816

EMBODIMENTS

Cutting inserts1in embodiments may be described in detail below with reference to the drawings. For the sake of description, the drawings referred to in the following may illustrate, in simplified form, only main members necessary for describing the embodiments. The following cutting inserts1may therefore be capable of including any arbitrary structural member not illustrated in the drawings referred to. Dimensions of the members in each of the drawings faithfully may represent neither dimensions of actual structural members nor dimensional ratios of these members.

<Cutting Inserts>

The cutting insert1(hereinafter also referred to simply as “insert1”) may include a base9including, for example, a first surface3, a second surface5and a lateral surface7as illustrated inFIG.1. The first surface3may have a polygonal shape including a plurality of corners and a plurality of sides as illustrated inFIG.2. The second surface5may be located on a side opposite to the first surface3, and may include a plurality of corners and sides as in the first surface3. Accordingly, the insert1may have a polygonal plate shape as illustrated inFIG.1.

The first surface3may have an approximately triangular shape, and may include three corners and three sides as illustrated inFIG.2. Similarly to the first surface3, the second surface5may have an approximately triangular shape and may include three corners and three sides. The three corners and the three sides of the first surface3may be located so as to have rotational symmetry of 120° around a central axis O1in a front view of the first surface3.

Although the second surface5has the polygonal shape as in the first surface3, there is no limitations to dimensions identical to those of the first surface3. For example, the second surface5may be somewhat smaller than the first surface3. As used herein, the polygonal shape is not limited to a strict polygonal shape. For example, the three sides of the first surface3may not be individually a strict straight line.

Each of the three sides may include a part protruded outward and a part protruded inward as in the embodiment illustrated inFIG.2. As used herein, the term “central axis O1” may be rephrased as an imaginary straight line connecting a center of the first surface3and a center of the second surface5. The center of the first surface3may be determined, for example, by a position of a center of gravity of the first surface3in the front view of the first surface3.

The shapes of the first surface3and the second surface5are not limited to the above shape. The first surface3may have an approximately triangular shape as illustrated inFIG.1. Alternatively, the first surface3and the second surface5may have, for example, a quadrangular shape, pentagonal shape, hexagonal shape or octagonal shape.

The first surface3may include a first corner11, a second corner13, a third corner15, a first side17and a second side19. The second corner13and the third corner15may be individually located adjacent to the first corner11. The first side17may be located between the first corner11and the second corner13. In other words, the first side17may connect to the first corner11and the second corner13. The second side19may be located between the first corner11and the third corner15. In other words, the second side19may connect to the first corner11and the third corner15.

The lateral surface7may be located between the first surface3and the second surface5in the present disclosure. The lateral surface7may connect to the first surface3and the second surface5in the embodiment illustrated inFIG.1. Because the first surface3may include the first side17and the second side19, the lateral surface7may include a first lateral surface21located along the first side17and a second lateral surface23located along the second side19.

As in the embodiment illustrated inFIG.1, the first lateral surface21may be located from the first side17to the second surface5, and the second lateral surface23may be located from the second side19to the second surface5. Because the first side17and the second side19may be located adjacent to each other as described above, the first lateral surface21and the second lateral surface23may also be located adjacent to each other.

The first lateral surface21may include a first rake surface region. The second lateral surface23may include a second rake surface region. The first lateral surface21and the second lateral surface23may be individually servable as a rake surface in a cutting process.

Because the first surface3has the approximately triangular shape as in the embodiment illustrated inFIG.2, the first surface3may include a third side25in addition to the first side17and the second side19, and the lateral surface7may further include a third lateral surface27located from the third side25to the second surface5, in addition to the first lateral surface21and the second lateral surface23. The third side25may be located between the second corner13and the third corner15in the embodiment illustrated inFIG.2.

As described above, the three corners and the three sides of the first surface3may be located so as to have rotational symmetry of 120° around the central axis O1in the front view of the first surface3as in the embodiment illustrated inFIG.2. Additionally, the first lateral surface21, the second lateral surface23and the third lateral surface27may also be located so as to have rotational symmetry of 120° around the central axis O1.

The whole of an intersection of the first surface3and the lateral surface7need not be a ridgeline. For example, a part of the intersection of the first surface3and the lateral surface7where a cutting edge is formed may correspond to the ridgeline, and a part of the intersection of the first surface3and the lateral surface7where no cutting edge is formed may not be the ridgeline. In other words, the first surface3may smoothly connect to the lateral surface7in the part of the intersection of the first surface3and the lateral surface7where no cutting edge is formed.

A visible range in the front view of the first surface3may correspond to the first surface3. Therefore, the first corner11, the second corner13, the third corner15, the first side17, the second side19and the third side25may be located on an outer peripheral edge of the first surface3in the front view of the first surface3. This may make it possible to determine a boundary between the first surface3and the lateral surface7even if a portion of an outer peripheral part of the first surface3is curved in a convex curved surface shape so as to obtain a partial smooth connection of the first surface3and the lateral surface7as in the embodiment illustrated inFIG.1.

A maximum width of the first surface3may be, for example, 6-25 mm in the front view of the first surface3. A height from the first surface3to the second surface5may be, for example, 1-10 mm. As used herein, the term “height from the first surface3to the second surface5” may denote a maximum value of a distance between the first surface3and the second surface5in a direction parallel to the central axis O1.

The insert1may include a through hole29that opens into the first surface3as illustrated inFIG.1. The through hole29may be formed from the center of the first surface3toward the center of the second surface5in the embodiment illustrated inFIG.1. Therefore, the through hole29may open into the second surface5. Alternatively, a central axis of the through hole29may coincide with the central axis O1if the through hole29is formed from the center of the first surface3toward the center of the second surface5as in the embodiment illustrated inFIG.1.

The through hole29may be used to insert, for example, a screw if fixing the insert1to the holder. Instead of the screw, for example, a clamping member may be used to fix the insert1to the holder. Although the through hole29is formed from the center of the first surface3toward the center of the second surface5in the embodiment illustrated inFIG.1, the through hole29is not limited to the above configuration.

As illustrated inFIG.3, the second surface5may include a flat surface region5alocated so as to surround an opening of the through hole29. If the second surface5includes the surface region5a, the insert1may be stably fixable to the holder. The surface region5ais not limited to a strict flat surface.

The surface region5amay be approximately flat, and specifically may be slightly curved or may have slight irregularities, both of which are unremarkable on the whole. More specifically, the surface region5amay include, for example, slight irregularities of approximately several tens of μm.

The surface region5amay be orthogonal to the central axis O1. The insert1may be more stably fixable to the holder if the surface region5ais orthogonal to the central axis. If the second surface5includes the surface region5a, the surface region5amay be used as a first reference plane in order to determine a positional relationship in a direction along the central axis O1.

The base9may further include a first cutting edge31, a second cutting edge33, a third cutting edge35and a fourth cutting edge37. These cutting edges may be used to cut out a workpiece if the insert1is used to manufacture a machined product. The first cutting edge31may be located on the first side17. The second cutting edge33may be located on the second side19.

The first cutting edge31may be located on a whole of the first side17, or may be located on a part of the first side17. The second cutting edge33may be located on a whole of the second side19, or may be located on a part of the second side19.

The first cutting edge31may be located on the whole of the first side17, or may be located only on the part of the first side17. The second cutting edge33may be located on the whole of the second side19, or may be located only on the part of the second side19.

The third cutting edge35may be extended from the second corner13toward the second surface5. The fourth cutting edge37may be extended from the first corner11toward the second surface5. The third cutting edge35may be located on an intersection of the first lateral surface21and the third lateral surface27as in the embodiment illustrated inFIG.1. The fourth cutting edge37may be located on an intersection of the first lateral surface21and the second lateral surface23as in the embodiment illustrated inFIG.1.

The third cutting edge35may connect to the second surface5or may be located away from the second surface5. Similarly, the fourth cutting edge37may connect to the second surface5or may be located away from the second surface5.

For example, if a cutting process of a workpiece is carried out using the insert1in a state where the first lateral surface21serves as a rake surface, the third cutting edge35may be used as a bottom cutting edge, and the first cutting edge31may be used as an outer peripheral cutting edge. In cases where the third cutting edge35is used as the bottom cutting edge and the first cutting edge31is used as the outer peripheral cutting edge as described above, the first cutting edge31may mainly contribute to the cutting process. The first cutting edge31may be called a main cutting edge in some cases.

If a cutting process of a workpiece is carried out using the insert1in a state where the second lateral surface23serves as a rake surface, the fourth cutting edge37may be used as a bottom cutting edge, and the second cutting edge33may be used as an outer peripheral cutting edge. In cases where the fourth cutting edge37is used as the bottom cutting edge and the second cutting edge33is used as the outer peripheral cutting edge as described above, the second cutting edge33may mainly contribute to the cutting process. The second cutting edge33may also be called a main cutting edge in some cases.

If the three sides of the first surface3are located so as to have rotational symmetry of 120° around the central axis O1, a cutting edge part corresponding to the first cutting edge31may be located on the third side25. If the first lateral surface21, the second lateral surface23and the third lateral surface27are located so as to have rotational symmetry of 120° around the central axis O1, a cutting edge part corresponding to the third cutting edge35may be located on an intersection of the second lateral surface23and the third lateral surface27.

The first side17may include a first portion39, a second portion41, a third portion43and a fourth portion45. The first portion39may be extended from the first corner11toward the second corner13. The second portion41may be located closer to the second corner13than the first portion39.

The third portion43may be located closer to the second corner13than the second portion41. The fourth portion45may be extended from the second corner13toward the first corner11. The first portion39, the second portion41, the third portion43and the fourth portion45may be located in this order in a direction from the first corner11to the second corner13on the first side17.

FIG.2may illustrate a reference line L. The reference line L may be an imaginary straight line that is in contact with the first portion39at an end portion on a side of the first corner11in the front view of the first surface3. The second portion41and the fourth portion45may be inclined relative to the reference line L so as to be located away from the reference line L on a side where the center of the first surface3is located, as going away from the first portion39. Specifically, the second portion41and the fourth portion45may be located away from the reference line L toward a right side as going away from the first portion39in the front view of the first surface3as illustrated inFIG.2.

FIG.2may illustrate a first angle θ1, a second angle θ2, a third angle θ3and a fourth angle θ4. The first angle θ1may be an inclination angle of the first portion39with respect to the reference line L. The second angle θ2may be an inclination angle of the second portion41with respect to the reference line L. The third angle θ3may be an inclination angle of the third portion43with respect to the reference line L. The fourth angle θ4may be an inclination angle of the fourth portion45with respect to the reference line L.

If the inclination angle of the first portion39is not kept constant, a maximum value thereof may be employed as the first angle θ1. Similarly, if the inclination angles of the second portion41, the third portion43and the fourth portion45are not kept constant, their individual maximum values may be respectively employed as the second angle θ2, the third angle θ3and the fourth angle θ4. As described above, the reference line L may be in contact with the first portion39at the end portion on the side of the first corner11in the front view of the first surface3. Therefore, if the first portion39has a straight line shape, the first angle θ1may be 0°.

The third angle θ3may be smaller than each of the second angle θ2and the fourth angle θ4. If the third angle θ3is relatively smaller than each of the second angle θ2and the fourth angle θ4, it may be easy to ensure space that permits passage of chips generated by the first cutting edge31. This may lead to enhanced chip discharge performance, and chip clogging may be less likely to occur.

If the second angle θ2is relatively larger than the third angle θ3, it may be easy to ensure a large length of the first cutting edge31without making the base9larger than necessary. This may make it possible to apply to, for example, high-cutting-depth process, thus leading to an increased degree of freedom in cutting process. If the fourth angle θ4is relatively larger than the third angle θ3, it may be easy to ensure a large thickness of the base9located close to the third cutting edge35. This may lead to enhanced durability of the third cutting edge35.

The first angle θ1may be smaller than each of the second angle θ2and the fourth angle θ4. If the first angle θ1is relatively smaller than each of the second angle θ2and the fourth angle θ4, it may be easy to ensure a large thickness of the base9located close to the fourth cutting edge37. Specifically, it may be easy to ensure a large angle at which the first lateral surface21intersects with the second lateral surface23. This may lead to enhanced durability of the fourth cutting edge37.

The third portion43may be inclined relative to the reference line L so as to be located away from the reference line L on the side where the center of the first surface3is located, as going way from the first portion39. Specifically, the third portion43may be located away from the reference line L toward a right side as going away from the first portion39in the front view of the first surface3as illustrated inFIG.2. If the third portion43is inclined as described above, it may be easy to ensure a larger space that permits passage of chips generated by the first cutting edge31. This may lead to further enhanced chip discharge performance, and chip clogging may be much less likely to occur.

The fourth angle θ4may be larger than the second angle θ2. In this case, it may be easy to ensure a larger thickness of the base9located close to the third cutting edge35. This may lead to further enhanced durability of the third cutting edge35.

The first angle θ1, the second angle θ2, the third angle θ3and the fourth angle θ4are not limited to a specific value. For example, the first angle θ1may be set to approximately 0-10°. The second angle θ2may be set to approximately 5-30°. The third angle θ3may be set to approximately 3-15°. The fourth angle θ4may be set to approximately 5-30°.

The first cutting edge31may be located on the whole of the first side17as described above, or alternatively may be located at the second portion41, the third portion43and the fourth portion45as in the embodiment illustrated inFIG.2. That is, the first cutting edge31may not be located at the first portion39on the first side17.

If the first cutting edge31is not located at the first portion39, the first surface3can smoothly connect to the lateral surface7at the first portion39. Thus, the second cutting edge33can smoothly connect to the fourth cutting edge37. In this case, any corner may be less likely to be formed in the vicinity of a boundary between the second cutting edge33and the fourth cutting edge37, but a so-called corner cutting edge having a convex curvilinear shape can be formed in a front view of the second lateral surface23.

The fourth portion45may have a convex curvilinear shape in a front view of the first lateral surface21. The fourth portion45may be extended from the second corner13and may therefore connect to the third cutting edge35. If the fourth portion45constituting a part of the first cutting edge31has the convex curvilinear shape, the fourth portion45may be servable as a corner cutting edge having enhanced durability. Hence, the first cutting edge31may have enhanced durability if the first cutting edge31and the third cutting edge35are used to carry out a cutting process.

The third portion43may have a straight line shape inclined so as to be located away from the second surface5as going away from the fourth portion45in the front view of the first lateral surface21. If the third portion43is inclined as described above, chips may have a smaller thickness, thereby reducing a cutting load applied to the third portion43. Additionally, if the third portion43has the straight line shape, the third portion43may have enhanced durability.

For example, a radial rake may be set to a negative value in order that the first surface3is less likely to come into contact with a workpiece if attaching the insert1to the holder. If the third portion43is inclined as described above, an angle formed by a machined surface of the workpiece formed by the third cutting edge35and a machined surface of the workpiece formed by the first cutting edge31can be brought close to 90°. This may make it possible to suitably carry out, for example, shoulder milling.

The second portion41may have a convex curvilinear shape in the front view of the first lateral surface21. The first cutting edge31may have enhanced durability if a part of the first cutting edge31which is located on a most outer peripheral side has the above convex shape in a state where the insert1is attached to the holder.

The first portion39may have a straight line shape that is inclined so as to come closer to the second surface5as coming closer to the first corner11in the front view of the first lateral surface21. If the first portion39is inclined as described above, the first portion39where the first cutting edge31is not located may less be likely to come into contact with the workpiece if the first cutting edge31is used to carry out the cutting process. Consequently, the second cutting edge33and the fourth cutting edge37that are located close to the first portion39may less be susceptible to damage.

Therefore, after the cutting process is carried out using the first cutting edge31and the third cutting edge35, it may be possible to suitably carry out a cutting process using the second cutting edge33and the fourth cutting edge37.

The first lateral surface21may include a first inclined surface47and a first flat surface49. The first inclined surface47may be located along the first cutting edge31and the third cutting edge35. The first inclined surface47may be inclined so as to come closer to a center of the base9as going away from the first cutting edge31and the third cutting edge35, and may serve as a so-called rake surface. That is, the first inclined surface47may correspond to the first rake surface region described earlier.

The first flat surface49may be located further away from the first cutting edge31and the third cutting edge35than the first inclined surface47. The first flat surface49may be usable as a surface brought into contact with a pocket of the holder if fixing the insert1to the holder. The insert1may be stably fixable to the holder because the first flat surface49has a flat surface configuration. The first flat surface49may be inclined relative to the second surface5, and may be orthogonal to the second surface5as illustrated inFIG.4.

The second lateral surface23may include a second inclined surface51and a second flat surface53. The second inclined surface51may be located along the second cutting edge33and the fourth cutting edge37. The second inclined surface51may be inclined so as to come closer to the center of the base9as going away from the second cutting edge33and the fourth cutting edge37, and may serve as a so-called rake surface. That is, the second inclined surface51may correspond to the second rake surface region described earlier.

The second flat surface53may be located further away from the second cutting edge33and the fourth cutting edge37than the second inclined surface51. The second flat surface53may be usable as a surface brought into contact with the pocket of the holder if fixing the insert1to the holder. The insert1may be stably fixable to the holder if the second flat surface53has a flat surface configuration. The second flat surface53may be inclined relative to the second surface5, and may be orthogonal to the second surface5as illustrated inFIG.5.

The first flat surface49and the second flat surface53are not limited to a strict flat surface. Similarly to the surface region5a, the first flat surface49and the second flat surface53may include slight irregularities of approximately several tens of μm.

For example, cemented carbide and cermet may be usable as a material of the insert1. Examples of composition of the cemented carbide may include WC—Co, WC—TiC—Co and WC—TiC—TaC—Co, in which WC, TiC and TaC may be hard particles, and Co may be a binding phase.

The cermet may be a sintered composite material obtainable by compositing metal into a ceramic component. Examples of the cermet may include titanium compounds composed mainly of titanium carbide (TiC) or titanium nitride (TiN). However, it is not intended to limit the material of the insert1to the above composition.

A surface of the insert1may be coated with a coating film by using chemical vapor deposition (CVD) method or physical vapor deposition (PVD) method.

Examples of composition of the coating film may include titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN) and alumina (Al2O3).

<Cutting Tools>

Cutting tools101in embodiments may be described below with reference toFIGS.12and13.FIGS.12and13may illustrate a state where the insert illustrated inFIG.1is attached to a pocket105of a holder103by a screw107. A rotation axis O2of the cutting tool101may be indicated by a two-dot chain line inFIG.12or the like.

The cutting tool101in a non-limiting embodiment may be used for a milling process. The cutting tool101may include the holder103and the insert as illustrated inFIG.12. The holder103may have a columnar shape extended from a first end to a second end along the rotation axis O2. The holder103may include the pocket105located on a side of the first end. The insert may be located in the pocket105.

The holder103may include only one pocket105, or alternatively, a plurality of pockets105as in an embodiment illustrated inFIG.12. If the holder103includes the pockets105, the cutting tool101may include a plurality of inserts, and the inserts may be located one by one in the pockets105.

The pocket105may open into an outer peripheral surface of the holder103and an end surface on a side of the first end. In cases where the holder103includes the pockets105, these pockets105may be located at equal intervals or unequal intervals around the rotation axis O2. As apparent from, for example, the fact that the holder103includes the pockets105, the holder103may not be a strict columnar shape.

The insert1may be attached to the pocket105so that at least a part of the cutting edge is protruded from the holder103. Specifically, the insert1may be attached to the holder103so that the first cutting edge is located more outside than the outer peripheral surface in the holder, and the second cutting edge is protruded from the holder toward a workpiece.

The second flat surface on the second lateral surface and the second surface of the insert may be in contact with at least the holder103in the cutting tool101of the non-limiting embodiment.

The insert may be attached to the pocket105by the screw107. The insert may be attached to the holder103by inserting the screw107into a screw hole of the insert, and by inserting a front end of the screw107into a screw hole formed in the pocket105so as to fix the screw107to the screw hole. For example, steel or cast iron may be usable as a material of the holder103. Of these materials, steel may be particularly used from the viewpoint of enhancing toughness of the holder103.

<Method for Manufacturing Machined Product>

Methods for manufacturing a machined product in embodiments may be described below with reference toFIGS.14to16.FIGS.14to16may illustrate a method for manufacturing a machined product in a cutting process using the above cutting tool. The rotation axis O2of the cutting tool101may be indicated by a two-dot chain line as illustrated inFIGS.14to16. The machined product203may be manufacturable by carrying out the cutting process of the workpiece201. A manufacturing method of a non-limiting embodiment may include the following steps.

That is, the manufacturing method in the non-limiting embodiment may include:(1) rotating the cutting tool101represented by the foregoing non-limiting embodiment;(2) bringing the cutting tool101being rotated into contact with the workpiece201; and(3) moving the cutting tool101away from the workpiece201.

More specifically, firstly, the cutting tool101may be relatively brought near the workpiece201while rotating the cutting tool101in Y direction around the rotation axis O2as illustrated inFIG.14. The workpiece201may be then cut out by bringing the cutting edge of the cutting tool101into contact with the workpiece201as illustrated inFIG.15. Thereafter, the cutting tool101may be relatively moved away from the workpiece201as illustrated inFIG.16.

The workpiece201may be fixed and the cutting tool101may be brought near the workpiece201. The workpiece201may be fixed and the cutting tool101may be rotated around the rotation axis O2as illustrated inFIGS.14to16. The workpiece201may be fixed and the cutting tool101may be moved away as illustrated inFIG.16. In the above cutting process, the workpiece201may be fixed and the cutting tool101may be moved in each of the steps. However, it is not intended to limit to this embodiment.

For example, the workpiece201may be brought near the cutting tool101in the step (1). Similarly, the workpiece201may be moved away from the cutting tool101in the step (3). If it is desired to continue the cutting process, the step of bringing the cutting edge of the insert into contact with different portions of the workpiece201may be repeated while keeping the cutting tool101rotated.

Representative examples of material of the workpiece201may include carbon steel, alloy steel, stainless steel, cast iron and nonferrous metals.