JP2024078679A - Manufacturing method of amorphous alloy flakes - Google Patents

Abstract

An amorphous alloy ribbon having a laser irradiated portion can be cut or cleaved with stable processing quality.
[Solution] A method for manufacturing an amorphous alloy flake is disclosed, which includes a step of preparing a ribbon of amorphous alloy, a step of irradiating with a laser so that a recess is formed along the boundary of a target area in the ribbon, and a cutting or cleaving step of cutting or cleaving the ribbon along the boundary, wherein the cutting or cleaving step includes cutting or cleaving the ribbon by moving a cutting or cleaving processing part along a direction perpendicular to the surface of the ribbon from the opening side to the closing side of the recess on the surface of the ribbon.
[Selected figure] Figure 7

Description

This disclosure relates to a method for producing amorphous alloy flakes.

Considering the difficulty of processing amorphous alloy ribbons (difficulty in processing with respect to punching), a technique is known in which a laser is continuously irradiated onto the amorphous alloy ribbon in advance to form a continuous outline of the laser irradiated areas (recesses), and then punching is performed along the continuous outline.

JP 2022-40071 A

However, with the above-mentioned conventional technology, when punching along the contour line, depending on the punching direction, it is difficult to perform punching with stable processing quality on the laser irradiated area (recess).

Therefore, in one aspect, the present disclosure aims to make it possible to cut or cleave an amorphous alloy ribbon having a laser irradiated portion with stable processing quality.

In one aspect, a method for producing a ribbon of an amorphous alloy includes the steps of:
an irradiation step of irradiating the ribbon with a laser so as to form a recess along a boundary of a target region in the ribbon;
a cutting or breaking step of cutting or breaking the ribbon along the boundary,
A method for producing amorphous alloy flakes is provided, in which the cutting or cleaving process includes cutting or cleaving the ribbon by moving a cutting or cleaving processing part along a direction perpendicular to the surface of the ribbon from the opening side to the closing side of the recess on the surface of the ribbon.

In one aspect, the present disclosure makes it possible to cut or cleave a ribbon of amorphous alloy having a laser irradiated portion with stable processing quality.

1 is a schematic flow chart showing a method for manufacturing a laminated iron core to which the method for manufacturing amorphous alloy flakes according to the present embodiment is applied. FIG. 2 is an explanatory diagram of the present manufacturing method, and is a schematic diagram showing a manufacturing apparatus and a workpiece for implementing the present manufacturing method. 1 is a plan view of a portion of a workpiece on which discontinuous laser irradiated portions are formed. FIG. FIG. 4 is an enlarged view of a portion Q1 in FIG. 3 . FIG. 2 is a plan view illustrating an amorphous alloy piece. FIG. 3B is a diagram showing a schematic cross-sectional shape of a laser irradiation portion, and is a cross-sectional view taken along line AA in FIG. 3A. FIG. 6 is a cross-sectional view corresponding to the cross-sectional view shown in FIG. 5, and is an explanatory view of the punching direction and the like during press working. 6 is a cross-sectional view corresponding to the cross-sectional view shown in FIG. 5, which is an explanatory diagram showing a schematic state of a workpiece during press working. FIG. FIG. 13 is an explanatory diagram of a punching direction according to a comparative example. 11 is an explanatory diagram showing the positional relationship when a punch passes through a laser irradiation unit. FIG.

Each embodiment will be described in detail below with reference to the attached drawings. Note that the dimensional ratios in the drawings are merely examples and are not limiting. Also, shapes in the drawings may be partially exaggerated for the sake of explanation.

Figure 1 is a schematic flow chart showing a method for manufacturing a laminated core 30 to which the method for manufacturing amorphous alloy flakes 80 according to this embodiment is applied. Figure 2 is an explanatory diagram of this manufacturing method, and is a schematic diagram showing a manufacturing apparatus 100 and a workpiece W for implementing this manufacturing method.

This manufacturing method includes a preparation step (step S1) of preparing a ribbon of an amorphous alloy (hereinafter also referred to as "amorphous metal ribbon"). The concept of an amorphous metal ribbon includes, for example, a ribbon of a nanocrystalline alloy. A nanocrystalline alloy is an alloy in which nano-order α-Fe crystals (nanocrystals) are densely dispersed in an amorphous parent phase as a crystal structure. Such nanocrystalline alloys can achieve high magnetic flux density due to their high iron content, and can maintain low core loss even in the magnetic flux density range. Therefore, amorphous metal ribbons are suitable as materials for stator cores and rotor cores of rotating electrical machines.

In this preparation process, for example, the strip-shaped amorphous metal ribbon may be prepared in a state wound around a roll 40 (see FIG. 2). In this case, the strip-shaped amorphous metal ribbon winding body W0 wound from the roll 40 may be unwound (see arrow R2 in FIG. 2) and supplied to the next process as the amorphous metal ribbon workpiece W.

The manufacturing method then includes a laser irradiation step (step S2) (one example of an irradiation step) in which the amorphous metal ribbon is irradiated with a laser. The laser used in the laser irradiation step is arbitrary, but is preferably an ultrashort pulse laser. The ultrashort pulse laser has a pulse width of, for example, several femtoseconds to several picoseconds, and is advantageous in that it allows for highly accurate micromachining and can reduce thermal damage to the workpiece W. FIG. 2 shows a schematic diagram of a laser irradiation device 50. In FIG. 2, the laser irradiation device 50 is arranged so that it acts first on the workpiece W unwound from the roll 40, but a pretreatment device may be provided upstream of the laser irradiation device 50. For example, the amorphous metal ribbon may be subjected to a preliminary heat treatment at the time of preparation in the above-mentioned preparation step, or may be subjected to a preliminary heat treatment upstream of the laser irradiation device 50. In this case, the preliminary heat treatment may be performed under heating conditions that enhance the magnetic properties.

Here, when the amorphous metal ribbon of the work W is irradiated with a laser, a recess is formed in the amorphous metal ribbon. Hereinafter, such a recess is also referred to as a laser irradiation portion 70. In this manufacturing method, the laser irradiation process forms a plurality of laser irradiation portions 70 in a manner in which the laser irradiation portions 70 are spaced apart from each other (i.e., the laser irradiation portions 70 are scattered). That is, in this manufacturing method, the laser irradiation process does not form the laser irradiation portions continuously (seamlessly), but forms the plurality of laser irradiation portions 70 in a discontinuous manner in which they are separated from each other. Hereinafter, such a method of forming the laser irradiation portion 70 is also referred to as a method of forming a discontinuous type laser irradiation portion 70. On the other hand, a method of forming a plurality of laser irradiation portions 70 continuously (seamlessly) from each other is also referred to as a method of forming a continuous type laser irradiation portion. In addition, in a modified example, a continuous type laser irradiation portion may be formed.

Now, with reference to Figures 3 and 4, a method for forming discontinuous laser irradiation portion 70 will be described. Here, a method for forming discontinuous laser irradiation portion 70 for forming a stator core for a rotating electric machine will be described, but it can also be applied to forming a stator core for a rotating electric machine or other laminated cores.

Figure 3 is a plan view of a portion of the workpiece W in which a discontinuous laser irradiated portion 70 is formed, and Figure 3A is an enlarged view of part Q1 in Figure 3. Figure 4 is a plan view that shows a schematic diagram of an amorphous alloy piece 80.

In this manufacturing method, as shown in FIG. 3, discontinuous laser irradiation portion 70 is formed along the boundary of the stator core region for forming the stator core (the outline of the punched shape). Specifically, discontinuous laser irradiation portion 70 is formed along cutting target portion 320 that defines the inner peripheral edge of the stator core, cutting target portion 322 that defines the slots of the stator core, and cutting target portion 328 that defines the outer peripheral edge of the stator core.

The cutting target portions 320, 322, and 328 may be formed in the same manner (various parameters a, b, c, d and depth h in FIG. 3A, etc.) or in different manners according to their respective characteristics.

For example, the cutting target portion 328 may be formed in such a manner that the width a, length b, gap c, and pitch d of the laser irradiated portion 70 are controlled, as shown in FIG. 3A. In this case, the portion corresponding to the gap c is not irradiated with the laser, and is hereinafter referred to as the "non-irradiated portion 72." The depth h (see FIG. 5) of the laser irradiated portion 70 may also be controlled. The various parameters a, b, c, d, and depth h may be adapted to achieve an optimal balance between reducing the amount of heat input and improving punchability (processability) during press processing, which will be described later.

In addition, in this manufacturing method, the depth h of the laser irradiated portion 70 is arbitrary, but since it has a non-irradiated portion 72, it may be set deep enough to exceed 70% of the thickness of the amorphous metal ribbon, but is set so as not to exceed 100%. Note that when it is 100%, the laser irradiated portion 70 will be in the form of a through hole rather than a recess.

In this manufacturing method, the ratio (=Σc/Σb) of the total length (=Σc) of the non-irradiated portion 72 in the cut target portion 328 (similarly for the other cut target portions 320, 322) to the total length (=Σb) of the laser-irradiated portion 70 in the cut target portion 328 is preferably 1/10 or more, more preferably 1/2 or more, and most preferably 1 or more. In this case, the amount of heat input can be effectively reduced while maintaining relatively good punchability (processability) during press processing.

Returning to FIG. 1, the manufacturing method then includes a press processing step (step S3) (an example of a cutting or cleaving step) in which each cutting target portion 320, 322, 328 in the amorphous metal ribbon workpiece W is cut by a press machine 60. This forms an amorphous alloy piece 80 as shown in FIG. 4. Note that each cutting target portion 320, 322, 328 may be cut simultaneously or may be cut separately using a progressive die. FIG. 2 shows a schematic of the press machine 60 downstream of the laser irradiation device 50. Note that in the case of a progressive die, multiple press machines 60 may be arranged in succession.

Next, the manufacturing method includes a lamination process (step S4) in which multiple amorphous alloy pieces 80 cut by press working are laminated to form the laminated core 30. The lamination process may be achieved, for example, by bonding the amorphous alloy pieces 80 together with an adhesive or the like.

As is generally known, amorphous metal ribbons have excellent magnetic properties (high magnetic flux density and low iron loss) and corrosion resistance, but are also difficult to process. Therefore, when cutting (punching) an amorphous metal ribbon using a press machine 60 without a laser irradiation unit 70, the durability of the punch 91 and die 90 of the press machine 60, which will be described later with reference to FIG. 6, decreases.

In this regard, according to the present manufacturing method, as described above, the cutting target portions 320, 322, and 328 pass through the multiple laser irradiation portions 70. As described above, the multiple laser irradiation portions 70 are in the form of recesses, and therefore are locations that are easy to cut with the press machine 60. Therefore, according to the present manufacturing method, by forming multiple laser irradiation portions 70 in the cutting target portions 320, 322, and 328, the processability (processability related to press processing) of the amorphous metal ribbon can be improved.

Here, if emphasis is placed solely on the aspect of improving the workability of press working, it is desirable that the proportion of the laser irradiated portion 70 in the portion to be cut 320 (the same applies to the other portions to be cut 322, 328, and so forth) be as large as possible. In other words, if emphasis is placed solely on the aspect of improving the workability of press working, ultimately, the continuous type laser irradiated portion described above is desirable, and the proportion of the laser irradiated portion 70 in the portion to be cut 320 is 100%.

However, in the case of continuous laser irradiation parts, the amount of heat input tends to be large, and problems such as changes in characteristics due to crystallization in the amorphous metal ribbon and thermal runaway caused by heat generation due to crystallization can easily occur.

In this regard, according to this embodiment, as described above, the laser irradiation process is performed so that multiple cutting target portions 320 are formed adjacent to one cutting target portion 320 via the non-irradiated portion 72. This makes it possible to reduce the amount of heat input to one cutting target portion 320. That is, according to this embodiment, by including the non-irradiated portion 72 that can reduce the amount of heat input in the cutting target portion 320, the heat input to one cutting target portion 320 can be reduced. This effectively reduces the possibility of the temperature of the workpiece W rising to a temperature range where the second peak p2 occurs. As a result, the above-mentioned inconveniences that occur in the case of a continuous type laser irradiation portion can be reduced.

Next, while still referring to FIG. 3A, the press working process (step S3) according to this embodiment will be further explained with reference to FIG. 5 onwards.

Figure 5 is a schematic diagram showing the cross-sectional shape of the laser irradiation section 70, and is a cross-sectional view taken along line A-A in Figure 3A. Figure 6 is an explanatory diagram of the punching direction during press working, etc., using a cross-sectional view corresponding to the cross-sectional view shown in Figure 5. Figure 7 is an explanatory diagram of the state of the workpiece W during press working, using a cross-sectional view corresponding to the cross-sectional view shown in Figure 5. Figure 8 is an explanatory diagram of the punching direction in a comparative example. In Figures 5 to 8, the Z direction (and the Z1 side and Z2 side) are defined along the direction perpendicular to the surface of the workpiece W (the surface of the amorphous metal strip).

In this embodiment, as described above and shown in FIG. 5, the laser irradiation unit 70 has the form of a recess (groove) with a depth h. Hereinafter, the open side of the recess of the laser irradiation unit 70 (the Z1 side in the Z direction in FIG. 5) is also simply referred to as the "open side of the laser irradiation unit 70," and the opposite side (the Z2 side in the Z direction in FIG. 5) is also simply referred to as the "closed side of the laser irradiation unit 70."

In this embodiment, the press processing includes moving (lowering) the punch 91 of the press 60 from the open side to the closed side of the laser irradiation unit 70 along the Z direction. That is, in this embodiment, the punching direction R6 is the direction from the open side to the closed side of the laser irradiation unit 70 along the Z direction. Note that the punch 91 may be in a form that overlaps the punched shape area (target area) when viewed in the Z direction, and the surface on the Z2 side may be substantially flat.

However, in press processing, burrs are likely to occur on the die 90 side of the cut surface. In this regard, in the comparative example shown in FIG. 8, since the press processing is performed along the Z direction from the closing side to the opening side of the laser irradiation section 70, if burrs occur, they are likely to occur on the laser irradiation section 70. When burrs occur on the laser irradiation section 70, the behavior of the burrs tends to become unstable. This is because the shape of the laser irradiation section 70 changes locally due to melting caused by the heat of the laser, and the shape and behavior of the burrs tend to differ for each individual part. In addition, the laser irradiation section 70 becomes brittle due to the heat of the laser, and the burrs are likely to break off. Therefore, even if the burrs on the laser irradiation section 70 are in a harmful form, they may be difficult to detect, and even if they are not in a harmful form, they may break off later and cause problems as foreign matter.

In contrast, according to this embodiment, as described above, the punching direction R6 is along the Z direction from the open side to the closed side of the laser irradiation section 70, so that if a burr occurs, it will be on the surface of the closed side of the workpiece W. In other words, the possibility of burrs occurring on the laser irradiation section 70 can be reduced. As a result, the above-mentioned inconveniences occurring in the comparative example shown in Figure 8 can be reduced.

In this embodiment, as shown in FIG. 6, the workpiece W is positioned relative to the press machine 60 (punch 91 and die 90) so that a position a certain distance e away from the edge of the laser irradiation section 70 is the starting position of cutting by the punch 91. That is, when the workpiece W is positioned relative to the die 90 and punch 91 in a plane perpendicular to the Z direction, the workpiece W is positioned so that a position a certain distance e away from the edge of the laser irradiation section 70 is the starting position of cutting by the punch 91. In FIG. 3A, the position of the certain distance e away from the edge of the laser irradiation section 70 is shown diagrammatically by a dashed line 900. Also, FIG. 6 shows the workpiece W and punch 91 positioned so that a position a certain distance e away from the edge of the laser irradiation section 70 is the starting position of cutting by the punch 91. In this case, the clearance between the punch 91 and the die 90 may be set to a value obtained by adding the width a of the laser irradiation section 70 and the certain distance e. If the fixed distance e is too large, the shear surface is likely to become unstable, so the fixed distance e may be adjusted taking into account punching properties, etc.

In this way, by setting the clearance between the punch 91 and the die 90 to be equal to or greater than the width a of the laser irradiation portion 70, the possibility that the starting point of cutting by the punch 91 will be the laser irradiation portion 70 can be reduced. In addition, because the clearance between the punch 91 and the die 90 is relatively large, damage to the punch 91, etc. can be reduced.

Here, FIG. 9 shows the positional relationship when the starting point of cutting by the punch 91A is the laser irradiation section 70. In this case, the press working is achieved in a manner in which the punch 91A passes through the laser irradiation section 70.

Even in this case, as in the present embodiment, the possibility of burrs occurring in the laser irradiated portion 70 can be reduced, but the punch 91A comes into direct contact with the laser irradiated portion 70, which may result in uncontrollable processing behavior and lead to variation.

In contrast, according to this embodiment, as described above, the possibility of the punch 91 coming into direct contact with the laser irradiated portion 70 can be reduced, and this inconvenience (the occurrence of variation due to uncontrollable processing behavior) can be reduced. That is, according to this embodiment, cutting can be performed from a starting point that avoids the laser irradiated portion 70, so the sheared surface can be stabilized. Note that in FIG. 7, the fracture image lines L70 and L72 associated with the tensile deformations R71 and R71 are shown diagrammatically along with the sheared surface formation image line L71.

Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or some of the components of the above-mentioned embodiments.

For example, in the above-mentioned embodiment, each amorphous metal ribbon is pressed separately, but multiple sheets may be stacked and pressed. This allows multiple amorphous alloy pieces 80 to be produced efficiently. Even in this case, the above-mentioned effects can be obtained by performing the press process from the opening side.

In the above-described embodiment, the workpiece W is positioned relative to the press machine 60 by moving the workpiece W relative to the press machine 60, which includes the die 90 and punch 91. However, instead of or in addition to this, the workpiece W may be positioned relative to the press machine 60 by moving the die 90 and punch 91.

70: Laser irradiated part (concave), 91: Punch (machined part), W: Work (thin strip of amorphous alloy)

Claims (4)

preparing a ribbon of an amorphous alloy;
an irradiation step of irradiating the ribbon with a laser so as to form a recess along a boundary of a target region in the ribbon;
a cutting or breaking step of cutting or breaking the ribbon along the boundary,
The cutting or cleaving process includes cutting or cleaving the ribbon by moving a cutting or cleaving processing part from the opening side to the closing side of the recess on the surface of the ribbon along a direction perpendicular to the surface of the ribbon. The method for producing amorphous alloy flakes according to claim 1, wherein the cutting or cleaving step is performed by positioning the ribbon relative to the movable tool so that a position a certain distance away from the edge of the recess is the starting position for cutting or cleaving. The method for producing amorphous alloy flakes according to claim 1, wherein the movable tool overlaps the target area when viewed in a direction perpendicular to the surface of the ribbon. The method for producing an amorphous alloy piece according to any one of claims 1 to 3, wherein the irradiation step includes irradiating a laser so that a plurality of laser irradiated portions are formed along the boundary in a manner in which the laser irradiated portions are adjacent to each other with non-irradiated portions interposed therebetween, and the plurality of laser irradiated portions form the recesses.