Cutting method

Abstract

A cutting method for forming a machined surface by cutting the surface of an object to be machined by bringing a tool, the corner of which is formed by a flank surface and a rake surface, into contact with the surface of the object to be machined and displacing the tool in a predetermined machining direction relative to the object to be machined. The cutting method includes a groove forming step of forming a plurality of groove portions extending in a direction intersecting the machining direction at intervals in the machining direction in a region on the downstream side in the machining direction in the surface of the object to be machined.

Description

Technical Field

[0001] The present invention relates to a cutting method for cutting the surface of an object to be processed to form a processed surface. Background Art

[0002] When cutting an object, when the tool is brought into contact with the object and displaced, the machining resistance accompanying the displacement may cause tool wear or local damage, etc. The more difficult the material is to machine, the more significant the disadvantage is.

[0003] Therefore, various techniques for reducing the machining resistance during cutting have been proposed, such as a technique in which the strength of the area in contact with the tool is reduced by irradiating the area in contact with the tool in advance with a laser, thereby heating the area just before the tool contacts the tool (see Patent Documents 1 and 2).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 9-155602

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 61-152345 Summary of the invention

[0008] Technical problem to be solved by the invention

[0009] However, since this technology reduces the strength of the object to be processed by heating with a laser, in order to make the area irradiated by the laser come into contact with the tool in a sufficiently heated state, processing must be performed immediately after heating. Therefore, there is a technical problem that the degree of freedom as a processing method may not be high.

[0010] The present invention has been made to solve the above-mentioned technical problems, and an object of the present invention is to provide a technology for reducing machining resistance while increasing the degree of freedom as a machining method.

[0011] Technical solutions for solving technical problems

[0012] The first aspect for solving the above-mentioned technical problem is a cutting method, which forms a processing surface by making a tool having a corner portion formed by a back cutting edge and a front cutting edge contact with the surface of a processing object, and displacing the tool relative to the processing object in a predetermined processing direction, thereby cutting the surface of the processing object to form a processing surface, and the cutting method has the following groove forming step: in a region on the surface of the processing object that becomes the downstream side of the processing direction, a plurality of groove portions extending in a direction intersecting the processing direction are formed at intervals in the processing direction. In addition, this aspect may also be the second aspect shown below. In the second aspect, in the groove forming step, as a boundary between a cutting object layer cut by the corner portion contacting the processing object and chips cut by the corner portion in this state, in a cross-sectional observation intersecting the extension direction of the corner portion, the groove portions are formed at intervals wider than the length L of the "shear surface" when assuming a "shear surface" from the surface of the cutting object layer to the front end of the corner portion.

[0013] According to the cutting method of the above aspect, a plurality of grooves extending in directions intersecting the machining direction are formed at intervals in a region on the downstream side of the surface of the object in the machining direction of the tool.

[0014] In the process of cutting the object to form a machined surface, a "shear surface" is formed from the surface of the cutting object layer to the front end of the corner when observed in a cross-section intersecting with the extension direction of the corner of the tool, as the boundary between the cutting object layer cut by the corner in contact with the object and the chips cut therefrom.

[0015] The "shearing surface" is inclined toward the downstream side of the machining direction from the front end of the corner portion, and the machining resistance when cutting chips from the cutting object layer changes according to the length. In this regard, as in the above aspect, when a groove is formed on the downstream side of the machining direction, the closer the corner portion is to the groove, the shorter the inclination and formation of the shearing surface are hindered by the groove, so the machining resistance can be reduced especially near the groove.

[0016] However, if the number of grooves increases and the intervals between them become too narrow, the area between the grooves is pressed by the corners and falls toward the downstream side, which hinders the displacement of the corners and may result in an increase in machining resistance.

[0017] The applicant of the present application has implemented innovative improvements focusing on the relationship between the spacing of such grooves and the processing resistance, and has found that the spacing of the grooves as described above is suitable for reducing the processing resistance. Therefore, according to the cutting method described above, the processing resistance can be effectively reduced.

[0018] Here, since the reduction in machining resistance is caused by the structural feature of the grooves formed at a predetermined interval, it is not necessary to perform machining immediately after the grooves are formed, unlike the feature of strength reduction caused by heating, which is easy to change with the passage of time. In this respect, the degree of freedom as a machining method is high. In this way, in the cutting method of the above aspect, the degree of freedom as a machining method can be increased, and the machining resistance can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a side cross-sectional view of a main part showing the process of the cutting method in the present disclosure.

[0020] Figure 2 Detailed description of the invention The following is a flowchart showing the steps of the cutting method in the present invention.

[0021] Figure 3 This is an enlarged side cross-sectional view of a main part showing the process of the cutting method in the present disclosure. DETAILED DESCRIPTION

[0022] Hereinafter, a cutting method for cutting the surface of an object to be processed to form a processed surface will be described with reference to the drawings.

[0023] (1) Steps of cutting method

[0024] The cutting method of this embodiment is as follows Figure 1 As shown, by bringing the tool 10 having the corner 15 formed by the back cutting surface 11 and the front cutting surface 13 into contact with the surface of the processing object 20, the tool 10 is displaced relative to the processing object 20 in a predetermined processing direction (see the arrow in the same figure), thereby cutting the surface of the processing object 20 to form a processing surface 21. It should be noted that the tool 10 is a tool with a front angle of 0 to 20 degrees.

[0025] In this cutting method, Figure 2 As shown, first, a displacement step (s110) is performed. Here, when the tool 10 is brought into contact with the surface of the object 20, the displacement in the processing direction relative to the object 20 is started. In this embodiment, after the tool 10 is displaced to contact the surface of the object 20, the object 20 side is displaced relative to the tool 10. According to this displacement, the surface of the object 20 is cut to form a processed surface 21.

[0026] The object 20 is configured to be displaceable in the processing direction relative to the tool 10 by a displacement mechanism (not shown). In the present embodiment, the object 20 is configured to be displaceable in the processing direction relative to the tool 10. In the present embodiment, the displacement speed can be selected from a range of 50 to 300 m / min.

[0027] Then, a groove forming step (s120) is performed. Here, with respect to the area (area reached by the corner 15) 23 on the surface of the object 20 that is downstream of the machining direction, by cutting the groove in the direction intersecting the machining direction ( Figure 1 The slit 110 extending in the processing direction is repeatedly irradiated with laser (more specifically, pulsed laser), thereby forming a plurality of grooves 30 extending in the processing direction at intervals. Each groove 30 is formed as a groove extending a certain length in a direction intersecting the processing direction.

[0028] Here, a groove 30 with a depth of 20 to 40 μm and a width of 20 to 200 μm is formed. As a specific example, depending on the material of the tool 10 and the object 20, a laser with a pulse width of 7 μs, an output of 2.0 to 3.0 W, a wavelength of 355 nm, and a frequency of 15 kHz is vertically irradiated to the surface of the object 20.

[0029] The laser is irradiated by the irradiation unit 100. The irradiation unit 100 includes an oscillator for outputting pulsed laser light, a vibration adjuster for adjusting the frequency of the laser light vibration, an attenuator (ATT) for adjusting the output of the laser light, a beam expander (EXP) for adjusting the diameter of the laser light, etc. The laser light passing through these is outputted through an optical lens and the above-mentioned slit 110, and the laser light is irradiated with the optical axis oriented in a predetermined direction.

[0030] The laser beam is irradiated at a cycle (for example, 0.04 to 2 ms) determined according to the displacement speed of the displacement step and the interval at which the grooves 30 are to be formed.

[0031] In addition, the grooves 30 are formed at intervals P (>L) wider than the length L of the shear surface 29. The shear surface 29 is formed as a boundary between the cutting target layer 25 cut by the corner 15 in contact with the object 20 and the chips 27 cut by the corner 15 in this state, and is a surface from the surface of the cutting target layer 25 to the front end of the corner 15 in a cross-sectional observation intersecting the extending direction of the corner 15. As a specific example, the grooves 30 are formed at intervals of 0.2 to 1.5 mm.

[0032] In addition, if Figure 3 As shown, the length L of the shearing surface 29 is defined by the following mathematical formula, which is based on the thickness d of the cutting target layer 25, the shearing angle formed by the processing surface 21 and the shearing surface 29. The rake angle α formed by the rake face 13 of the corner portion 15 and the surface orthogonal to the processing surface 21, and the average friction coefficient μ (=F / N) of the rake face specified by the friction force F and the vertical force N acting on the rake face 13. Here, the average friction coefficient μ of the rake face is a value of 0.25 or less specified based on the friction coefficient (0.25 to 0.4) between the materials of the processing object 20 and the tool 10 and the processing conditions, and the processing conditions are determined by the cutting speed (relative displacement speed of the tool 10 with respect to the processing object 20) and the smoothness of the surface of the tool 10. In the present embodiment, based on the friction coefficient of 0.25 to 0.4 of iron as the processing object 20 and the superhard alloy as the material of the tool 10, the processing conditions are adjusted so that the average friction coefficient μ of the rake face becomes 0.1 which is smaller than the friction coefficient.

[0033]

[0034] (2) Modification

[0035] As mentioned above, although embodiment of the present invention is described, the present invention is not limited to the above-mentioned embodiment, and it is needless to say that various forms can be adopted as long as they belong to the technical scope of the present invention.

[0036] For example, in the above-described embodiment, the case where the object 20 is displaced relative to the tool 10 in the displacement step is exemplified. However, the tool 10 may be displaced relative to the object 20 in the displacement step.

[0037] In the above embodiment, the groove forming step is performed at the same time as the displacement step. However, the groove forming step only needs to be performed before the displacement step, and does not need to be performed at the same time.

[0038] In addition, in the above-mentioned embodiment, the structure in which the groove part 30 is formed as a groove extending in the direction intersecting the processing direction is exemplified. However, each groove part 30 may also be a structure in which a plurality of holes or grooves are arranged in a row with a certain length in the direction intersecting the processing direction. In this case, in the groove forming step, the groove part 30 is formed by displacing the irradiation area of ​​the laser in the direction intersecting the processing direction respectively while irradiating the laser continuously or intermittently.

[0039] Furthermore, in the above-described embodiment, the case where the tool 10 is a one-stage rake angle tool is exemplified, but the tool 10 may also be a tool having a two-stage rake angle shape.

[0040] In the above embodiment, the groove forming step is described as follows: a groove extending in a direction intersecting the processing direction is formed by irradiating the surface of the object 20 with laser light through the slit 110. However, a lens that linearly expands the laser light in a direction intersecting the processing direction may be used instead of the slit 110.

[0041] In the above embodiment, the groove forming step is exemplified by irradiating the surface of the object 20 with laser light through the slit 110 to form a groove extending in a direction intersecting the machining direction. However, in the groove forming step, the surface of the object 20 may be irradiated with laser light in a direction intersecting the machining direction ( Figure 1 The laser is repeatedly scanned to form a groove extending in a direction intersecting the processing direction. In this case, a displacement mechanism can be provided to enable the irradiation unit 100 to be displaced in two directions intersecting the optical axis of the laser.

[0042] (3) Effect

[0043] According to the cutting method of the above embodiment, a plurality of grooves 30 extending in a direction intersecting the machining direction are formed at intervals in the region 23 on the surface of the object 20 that is on the downstream side in the machining direction of the tool 10 .

[0044] In the process of cutting the processing object 20 to form the processing surface 21, a shear surface 29 is formed from the surface of the cutting object layer 25 to the front end of the corner 15 in a cross-sectional observation intersecting with the extension direction of the corner 15 of the tool 10 as the boundary between the cutting object layer 25 cut by the corner 15 in contact with the processing object 20 and the chips cut therefrom.

[0045] The shearing surface 29 is inclined toward the downstream side in the machining direction with the front end of the corner portion 15 as the starting point, but there is a concern that the longer the shearing surface 29 is, the more the machining resistance when cutting the chips 27 from the cutting target layer 25 will increase. In this regard, as in the above-mentioned embodiment, if the groove portion 30 is formed on the downstream side in the machining direction, the closer the corner portion 15 is to the groove portion 30, the shorter the inclination and formation of the shearing surface 29 are hindered by the groove portion 30, so that the machining resistance in the vicinity of the groove portion 30 can be reduced.

[0046] However, if the grooves 30 are increased and the intervals therebetween become too narrow, the regions between the grooves 30 are pressed by the corners 15 and fall toward the downstream side, which hinders the displacement of the corners 15 and may result in an increase in machining resistance.

[0047] The applicant of the present application has focused on the relationship between the interval of the grooves 30 and the machining resistance and has made innovative improvements, and as a result, has found that the interval wider than the length L of the shear surface 29 as described above is suitable for reducing the machining resistance. Therefore, according to the above-mentioned cutting method, the machining resistance can be effectively reduced.

[0048] Here, since the reduction in machining resistance is caused by the structural feature of the grooves 30 formed at a predetermined interval, it is not necessary to perform machining immediately after forming the grooves 30, unlike the case where the strength is reduced due to heating and the condition easily changes with the passage of time, and the degree of freedom as a machining method is high in this respect. In this way, the above-mentioned cutting machining method can improve the degree of freedom as a machining method and reduce the machining resistance.

[0049] Description of Reference Numerals

[0050] 10: tool; 11: back face; 13: rake face; 15: corner; 20: object to be processed; 21: processing surface; 23: region; 25: cutting target layer; 29: shearing surface; 30: groove; 100: irradiation portion; 110: slit.

Claims

1. A cutting method, comprising: bringing a tool into contact with a surface of a workpiece and displacing the tool relative to the workpiece in a predetermined machining direction, thereby cutting the surface of the workpiece to form a machined surface, wherein the tool has a flank face and a rake face forming a corner portion, The cutting method comprises: a groove forming step of forming a plurality of grooves spaced apart in the machining direction in a region on the surface of the object to be machined that is on the downstream side in the machining direction, wherein the grooves extend in a direction intersecting the machining direction.

2. A cutting method, In the groove forming step, as the boundary between the cutting object layer cut by the corner portion in contact with the processing object and the chips cut by the corner portion in this state, in a cross-sectional observation intersecting the extension direction of the corner portion, assuming a "shear plane" from the surface of the cutting object layer to the front end of the corner portion, the groove portions are formed at intervals P that are wider than the length L of the "shear plane", that is, greater than L.

3. The cutting method according to claim 2, wherein: The length L of the shearing surface is defined by the following mathematical formula, which is based on the thickness d of the cutting target layer, the shearing angle between the processing surface and the shearing surface: a rake angle α formed by the rake face of the corner portion and a surface orthogonal to the processing surface, and an average friction coefficient μ of the rake face, wherein the average friction coefficient μ of the rake face is a value smaller than the friction coefficient between the materials of the processing object and the tool, The average friction coefficient μ of the rake face is a value of 0.25 or less, which is determined based on the friction coefficient of the material of the tool and the processing conditions.

4. The cutting method according to claim 1, wherein: In the groove forming step, the groove portion is formed by irradiating the laser beam continuously or intermittently while displacing an irradiation area of ​​the laser beam in directions intersecting the processing direction.

5. The cutting method according to claim 4, wherein: In the groove forming step, the groove portion is formed by irradiation with pulsed laser light.

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