Groove formation method and joining method

Abstract

To provide a groove formation method and a joining method that can improve the accuracy of the groove shape. [Solution] A groove forming method for forming grooves on the surface s13 of a first workpiece W1 made of metal using a laser, comprising a groove forming step in which a laser is irradiated onto the surface s13 of the first workpiece W1 from a laser head 100, and gas is sprayed onto the first workpiece W1 from a position spaced apart from the laser head 100 in a direction different from the direction of laser irradiation to the surface s13, thereby forming grooves 12 on the surface s13 of the first workpiece W1 while removing the parts of the first workpiece W1 that have been melted by the laser.

Description

Technical Field

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[0001] The present disclosure relates to a groove forming method and a bonding method.

Background Art

[0002] For example, Japanese Patent Application Laid-Open No. 2014-166693 discloses a method of forming pores on the surface of a metal molded body to be joined to a resin molded body by irradiating laser light.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the method as described in Japanese Patent Application Laid-Open No. 2014-16,6693, there is a need to improve the shape accuracy of the groove.

[0005] An object of the present disclosure is to provide a groove forming method and a bonding method capable of improving the shape accuracy of a groove.

Means for Solving the Problems

[0006] A groove forming method according to an aspect of the present disclosure is a groove forming method for forming a groove on the surface of a first workpiece made of metal and to be joined to a second workpiece containing resin by laser, the method including a groove forming step of irradiating the surface of the first workpiece with the laser from a laser head and ejecting gas toward the first workpiece in a direction different from the irradiation direction of the laser with respect to the surface from a position separated from the laser head, thereby forming the groove on the surface of the first workpiece while removing a portion melted by the laser in the first workpiece.

[0007] A joining method according to one aspect of the present disclosure comprises a preparation step of preparing a first workpiece made of metal and a second workpiece containing resin, and a joining step of joining the first workpiece and the second workpiece to each other by laser while the first workpiece and the second workpiece are superimposed on each other, wherein in the preparation step, the first workpiece is prepared as the first workpiece formed by the groove forming method, and in the joining step, with the first workpiece and the second workpiece superimposed on each other such that the groove faces the second workpiece, the first workpiece and the second workpiece are joined by heating the portion of the outer surface of the first workpiece that overlaps with the groove in the thickness direction of the first workpiece by laser, thereby causing a portion of the resin constituting the second workpiece to enter into the groove. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a groove formation method and a joining method that can improve the shape accuracy of the groove. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic perspective view showing a groove formation method in one embodiment of the present disclosure. [Figure 2] This diagram schematically shows the gas injection range relative to the first workpiece in a plan view. [Figure 3] This diagram schematically shows the gas injection range relative to the first workpiece in a side view. [Figure 4] This diagram schematically shows the state in which the first workpiece and the second workpiece are superimposed on each other. [Figure 5] Figure 4 shows front views of the first and second workpieces. [Figure 6] This is a schematic cross-sectional view showing the state in which the first workpiece and the second workpiece are joined together. [Figure 7] This figure schematically shows a modified example of a groove formed in the first workpiece. [Figure 8] This figure schematically shows a modified example of a groove formed in the first workpiece. [Figure 9] This is a schematic perspective view showing a modified example of the groove formation process. [Modes for carrying out the invention]

[0010] Embodiments of this disclosure will be described with reference to the drawings. In the drawings referred to below, the same or equivalent components are given the same number.

[0011] Figure 1 is a schematic perspective view showing a groove formation method in one embodiment of the present disclosure. This groove formation method is a method for forming grooves 12 on the surface of a first workpiece W1 made of metal using a laser.

[0012] The first workpiece W1 is made of metal (iron, aluminum, etc.). The first workpiece W1 is formed in a flat plate shape. The first workpiece W1 is joined to the second workpiece W2 (see Figure 4), which contains resin. As shown in Figure 1, the first workpiece W1 has a pair of first end faces s11, a pair of second end faces s12, an opposing surface s13, and an outer surface s14.

[0013] The first end face s11 is formed at the end of the first workpiece W1 in a direction perpendicular to the thickness direction (Z direction in Figure 1) (X direction in Figure 1). The second end face s12 is formed at the end of the first workpiece W1 in a direction perpendicular to both the thickness direction and the direction connecting the pair of first end faces s11 (Y direction in Figure 1).

[0014] The opposing surface s13 is the surface of the first workpiece W1 that faces the second workpiece W2, out of a pair of main surfaces (surfaces). The outer surface s14 is the surface of the first workpiece W1 that is formed on the side opposite to the opposing surface s13 in the thickness direction of the first workpiece W1, out of a pair of main surfaces of the first workpiece W1.

[0015] The groove forming method in this embodiment includes a groove forming process. In the groove forming process, a laser is irradiated from the laser head 100 onto the surface of the first workpiece W1 (in this embodiment, the opposing surface s13), and a gas is injected from a position spaced apart from the laser head 100 in a direction different from the irradiation direction of the laser with respect to the surface, thereby forming a groove 12 on the surface of the first workpiece W1 while removing the portion melted by the laser in the first workpiece W1.

[0016] As shown in FIG. 1, in the groove forming process in this embodiment, the mounting table 2, the laser head 100, and the gas injection unit 200 are used.

[0017] The mounting table 2 is a table on which the first workpiece W1 is mounted. The surface of the mounting table 2 is formed flat.

[0018] The laser head 100 is movable along the surface of the first workpiece W1. The laser head 100 can irradiate a laser extending in a line shape (linear shape) or a spot shape (pinhole shape). The laser head 100 can irradiate, for example, a single-mode fiber laser. The laser head 100 is configured to be able to adjust the output of the laser within the range of 800 kN to 1250 kN. Note that the laser head 100 may inject shielding gas (for example, air) from the laser irradiation part. Shielding gas (for example, air) may be injected.

[0019] The gas injection unit 200 is capable of injecting gas onto the first workpiece W1 so as to remove the portion of the first workpiece W1 that has been melted by the laser. The gas injected from the gas injection unit 200 is for the purpose of removing the melted portion of the first workpiece W1 within the groove 12, and is a gas that has a different purpose and function from the shielding gas injected from the laser head 100. The gas injected from the gas injection unit 200 is, for example, a mixture of nitrogen, oxygen, carbon dioxide, and argon. The gas injection unit 200 is positioned at a distance from the laser head 100. The gas injection unit 200 is capable of injecting gas onto the first workpiece W1 from any direction. The gas injection unit 200 is configured to allow adjustment of the gas flow rate in the range of 25 L / min to 30 L / min.

[0020] As shown in Figure 1, when the laser head 100 irradiates a laser that extends in a line from one first end face s11 to the other first end face s11, it is preferable that the gas injection unit 200 injects gas from one first end face s11 to the other first end face s11.

[0021] In this case, as shown in Figure 2, it is preferable that the direction of gas injection to the first workpiece W1 in plan view be set within the range between a direction inclined by a first angle θ1 to one side with respect to a straight line L that is perpendicular to the first end face s11 and passes through the groove 12 (indicated by arrow AR1) and a direction inclined by a first angle θ1 to the other side with respect to the straight line L (indicated by arrow AR2). The first angle θ1 may be, for example, 22.5 degrees.

[0022] Furthermore, as shown in Figure 3, the gas injection direction relative to the first workpiece W1 in a side view is preferably set within a range between a direction parallel to the surface of the first workpiece W1 (opposing surface s13) (indicated by arrow AR3) and a direction inclined by a second angle θ2 toward the surface of the first workpiece W1 from this direction (indicated by arrow AR4). The second angle θ2 may be, for example, 45 degrees.

[0023] In the groove forming step of this embodiment, a groove 12 is formed that has a shape extending linearly in the direction connecting a pair of first end faces s11 (the X direction in Figure 1). However, in the groove forming step, a groove 12 may be formed that has a shape extending in the direction connecting a pair of second end faces s12, or a groove 12 may be formed that extends so as to connect the first end face s11 and the second end face s12. Furthermore, the groove 12 is not limited to a linear shape, but may be formed in a shape that is partially or entirely curved. The angle θ (see Figure 5) between the groove 12 formed in the groove forming step and the opposing surface s13 may be set to, for example, about 10 degrees.

[0024] Next, a joining method for joining the first workpiece W1 and the second workpiece W2 will be described with reference to Figures 4 to 7. This joining method includes a preparation step and a joining step.

[0025] The preparation step involves preparing the first workpiece W1 formed by the groove forming method described above, and the second workpiece W2 containing resin. As shown in Figure 4, the second workpiece W2 is formed, for example, in the shape of a flat plate. The second workpiece W2 may contain carbon fibers, glass fibers, or the like.

[0026] The joining process involves joining the first workpiece W1 and the second workpiece W2 together using a laser while they are superimposed on each other. In the joining process, first, as shown in Figures 4 and 5, the first workpiece W1 and the second workpiece W2 are superimposed on each other so that the groove 12 faces the second workpiece W2. At this time, the space S (see Figure 5) enclosed by the groove 12 and the second workpiece W2 communicates with the outside of the first workpiece W1 and the second workpiece W2. The first workpiece W1 and the second workpiece W2 are superimposed on each other. In the example shown in Figure 4, the length of the first workpiece W1 in the direction connecting the pair of first end faces s11 is set to be the same as the length of the second workpiece W2 in the same direction, and the space S opens to the first end face s11 of the first workpiece W1. In the joining process, with the first workpiece W1 and the second workpiece W2 superimposed on each other, the portion of the outer surface s14 of the first workpiece W1 that overlaps with the groove 12 in the thickness direction of the first workpiece W1 is heated with a laser, thereby joining the first workpiece W1 and the second workpiece W2 while a portion of the resin constituting the second workpiece W2 enters into the groove 12. In the joining process, it is preferable that the portion of the first workpiece W1 and the second workpiece W2 heated by the laser is pressurized. Figure 6 shows the state after the completion of this joining process.

[0027] The laser used in the joining process may be the same as the laser used in the groove formation process, or it may be different.

[0028] As described above, in the groove forming method of this embodiment, by injecting gas onto the first workpiece W1 from a position spaced apart from the laser head 100 in a direction different from the laser irradiation direction, the portion of the first workpiece W1 that has been melted by the laser is removed, thereby improving the shape accuracy of the groove 12.

[0029] Furthermore, in the joining method of this embodiment, during the joining process, the portion of the outer surface s14 of the first workpiece W1 that overlaps with the groove 12 in the thickness direction of the first workpiece W1 is heated by a laser. As a result, a portion of the resin constituting the second workpiece W2 enters into the groove 12 formed in the first workpiece W1, and the gas generated when the resin melts is discharged to the outside of the first workpiece W1 through the groove 12. Therefore, the joining strength of the first workpiece W1 and the second workpiece W2 is improved.

[0030] Furthermore, as shown in Figures 7 and 8, in the groove forming process, a groove 12 having a constricted portion 12a in the middle of the depth direction (vertical direction in Figures 7 and 8) may be formed.

[0031] Furthermore, although the above embodiment shows an example in which the laser head 100 irradiates a laser that extends in a line (straight line), as shown in Figure 9, the laser head 100 may irradiate the surface of the first workpiece W1 with a spot (pinhole) laser. In this case, during the groove forming process, gas may be injected from the gas injection unit 200 to the area around the laser irradiation part on the surface of the first workpiece W1, that is, to an area separated by a predetermined distance from the irradiation part (the area shown by the diagonal lines in Figure 9). In this case, it is preferable that the direction of gas injection to the area be set within the range between a direction perpendicular to the surface of the first workpiece W1 and a direction inclined by a third angle toward the surface of the first workpiece W1 from this direction. The third angle may be, for example, 45 degrees.

[0032] Those skilled in the art will understand that the above-described exemplary embodiments are specific examples of the following embodiments.

[0033] [Aspect 1] A groove forming method for forming grooves on the surface of a first workpiece made of metal, which is joined to a second workpiece containing resin, by laser, A groove forming method comprising a groove forming step of irradiating the surface of the first workpiece with the laser from a laser head and injecting gas onto the first workpiece from a position spaced apart from the laser head in a direction different from the direction of laser irradiation to the surface, thereby forming grooves on the surface of the first workpiece while removing the portion of the first workpiece that has been melted by the laser.

[0034] In this groove formation method, gas is injected onto the first workpiece from a position away from the laser head in a direction different from the laser irradiation direction, thereby removing the parts of the first workpiece that have been melted by the laser, and thus improving the accuracy of the groove shape.

[0035] [Aspect 2] The groove forming method according to Embodiment 1, wherein in the groove forming step, the surface is irradiated with the laser extending in a line from one end face to the other end face of the first workpiece in a direction perpendicular to the thickness direction of the first workpiece, and the gas is injected from one end face to the other end face.

[0036] [Aspect 3] The groove forming method according to embodiment 1, wherein in the groove forming step, the laser is irradiated onto the surface in a spot shape, and the gas is sprayed onto the portion of the surface surrounding the laser irradiation area.

[0037] [Aspect 4] A preparation process for preparing a first workpiece made of metal and a second workpiece containing resin, The process includes a joining step of joining the first workpiece and the second workpiece together by a laser while they are superimposed on each other, In the preparation step, the first workpiece is prepared by forming a groove according to the groove forming method described in Embodiment 1. In the joining process, the first workpiece and the second workpiece are stacked on top of each other such that the groove faces the second workpiece, and the portion of the outer surface of the first workpiece that overlaps with the groove in the thickness direction of the first workpiece is heated by the laser, thereby joining the first workpiece and the second workpiece while a portion of the resin constituting the second workpiece enters into the groove.

[0038] In this joining method, during the joining process, the portion of the outer surface of the first workpiece that overlaps with the groove in the thickness direction of the first workpiece is heated by a laser. As a result, a portion of the resin constituting the second workpiece enters into the groove formed in the first workpiece, and the gas generated when the resin melts is discharged to the outside of the first workpiece through the groove, thereby improving the joining strength between the first and second workpieces.

[0039] It should be noted that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the description of the embodiments above, and further includes all modifications within the meaning and scope equivalent to the claims. [Explanation of Symbols]

[0040] 2 support base, 12 groove, 100 laser head, 200 gas injection section, s11 first end face, s12 second end face, s13 opposing surface, s14 outer surface, W1 first workpiece, W2 second workpiece.

Claims

1. A groove forming method for forming grooves on the surface of a first workpiece made of metal, which is joined to a second workpiece containing resin, by laser, A groove forming method comprising a groove forming step of irradiating the surface of the first workpiece with the laser from a laser head and injecting gas onto the first workpiece from a position spaced apart from the laser head in a direction different from the direction of laser irradiation to the surface, thereby forming grooves on the surface of the first workpiece while removing the portion of the first workpiece that has been melted by the laser.

2. The groove forming method according to claim 1, wherein in the groove forming step, the laser is irradiated onto the surface in a line extending from one end face to the other end face of the first workpiece in a direction perpendicular to the thickness direction of the first workpiece, and the gas is injected from one end face to the other end face.

3. The groove forming method according to claim 1, wherein in the groove forming step, the laser is irradiated onto the surface in a spot shape, and the gas is sprayed onto the portion of the surface surrounding the laser irradiation area.

4. A preparation step to prepare a first workpiece made of metal and a second workpiece containing resin, The process includes a joining step of joining the first workpiece and the second workpiece together by a laser while they are superimposed on each other, In the preparation step, the first workpiece is prepared that is formed by the groove forming method described in claim 1. In the joining process, the first workpiece and the second workpiece are stacked on top of each other such that the groove faces the second workpiece, and the portion of the outer surface of the first workpiece that overlaps with the groove in the thickness direction of the first workpiece is heated with the laser, thereby joining the first workpiece and the second workpiece while a portion of the resin constituting the second workpiece enters into the groove.

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