Method for manufacturing a composite member, and composite member

Abstract

To provide a method for manufacturing a composite member having excellent bonding strength and airtightness, and a composite member.SOLUTION: A method for manufacturing a composite member in which a metal member and a resin member are bonded includes: a laser processing step of laser processing a surface of the metal member; and a bonding step of directly bonding the resin member to the laser-processed surface of the metal member. In the laser processing step, a plurality of recesses having an inner surface with a surface roughness of 20 nm to 1000 nm and a depth of 15 μm to 60 μm are formed on the surface of the metal member at a density of 40% to 100%. A material of the metal member is copper or aluminum. In the laser processing step, a bonding texture made of dross or oxide is formed in a non-laser irradiated part.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a composite member and a composite member.

Background Art

[0002] Patent Document 1 discloses a method for manufacturing a composite member. In this manufacturing method, a composite member in which a metal member and a resin member are joined is manufactured. The surface of the metal member is roughened by laser processing. Since the resin member is joined to the roughened surface of the metal member, an anchor effect occurs and the flow path resistance at the joint increases. Therefore, the composite member manufactured by these manufacturing methods has excellent joint strength and airtightness.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since metal has higher strength than glass, ceramics, or resin, it is a promising candidate as the base material of a composite member. The manufacturing method described in Patent Document 1 has room for improvement from the viewpoint of further improving the joint strength and airtightness of a composite member having a metal member as the base material.

Means for Solving the Problems

[0005] According to one aspect of the present invention, there is provided a method for manufacturing a composite member in which a metal member and a resin member are joined. The manufacturing method includes a laser processing step of laser-processing the surface of the metal member, and a joining step of directly joining the resin member to the surface of the laser-processed metal member. The laser processing step forms a plurality of recesses having an inner surface with a surface roughness of 20 nm or more and 1000 nm or less on the surface of the metal member.

[0006] According to this manufacturing method, the surface of the metal member is laser processed. On the surface of the metal member after laser processing, a plurality of recesses that contribute to the anchor effect and the flow path resistance of the joint are formed. The plurality of recesses have an inner surface with a surface roughness of 20 nm or more and 1000 nm or less. Since the surface roughness is 20 nm or more, the surface area of the metal member increases. As a result, the anchor effect is improved and the flow path resistance of the joint increases. Since the surface roughness is 1000 nm or less, the filling property of the resin member into the recesses is improved. As a result, the anchor effect is improved and the flow path resistance of the joint increases. From the above, it is possible to provide a manufacturing method of a composite member having excellent bonding strength and airtightness.

[0007] In one embodiment, the depth of the plurality of recesses may be 15 μm or more and 60 μm or less. In this case, since the depth of the recesses is 15 μm or more, the surface area of the metal member further increases and the flow path resistance of the joint further increases. Since the depth of the recesses is 60 μm or less, the time required for the laser processing step is shortened and the productivity is improved.

[0008] In one embodiment, the laser processing step may form a plurality of dot-shaped recesses by pulsed laser. In this case, the surface area of the metal member further increases.

[0009] In one embodiment, the plurality of recesses may be circular or rectangular in plan view. In the case of circular recesses, the area of the joint interface becomes large and the length of the flow path of the joint interface can be increased, so the flow path resistance can be increased. In the case of rectangular recesses, the area of the joint interface is even larger than in the case of circular recesses. Moreover, in the case of rectangular recesses, since the flow path at the interface bends at a right angle, the flow path resistance can be further increased compared to the case of circular recesses.

[0010] In one embodiment, the plurality of recesses may have a width of 20 μm or more and 150 μm or less. The more the number of recesses receiving the shearing force, the more the load at the stress concentration location is dispersed. However, if the width of the recesses is too small, good filling of the resin member is inhibited. Therefore, by setting the width of the recesses to 20 μm or more and 150 μm or less, the bonding strength is improved.

[0011] In one embodiment, the laser processing step may form the plurality of recesses at a density of 40% or more and 100% or less. In this case, the surface area of the metal member further increases.

[0012] In one embodiment, the laser processing step may form a plurality of continuous groove-shaped recesses by a pulsed laser. In this case, damage to the metal member can be reduced.

[0013] In one embodiment, the laser processing step may arrange the plurality of recesses at a pitch of 1 time or more and 2 times or less the spot diameter of the laser. The actually formed recesses are usually larger than the spot diameter of the laser. Therefore, according to this configuration, the plurality of recesses can be efficiently arranged.

[0014] In one embodiment, the laser processing step may arrange the plurality of recesses via a wall portion lower than the surface of the metal member. In this case, the plurality of recesses can be arranged at a high density.

[0015] In one embodiment, the laser processing step may arrange the plurality of recesses via a wall portion having the surface of the metal member as the top. In this case, there are no sharp convex portions that would be the starting points of cracks in the resin member on the bonding surface with the resin member. Therefore, the occurrence of cracks in the resin member is suppressed.

[0016] In one embodiment, the laser processing step may form the plurality of recesses such that the inclination angle of the inner surface is 40 degrees or more and 80 degrees or less. In this case, since the inclination angle of the inner surface of the recess is 40 degrees or more, the flow path resistance of the joint portion further increases and the airtightness further improves. Since the inclination angle of the inner surface of the recess is 80 degrees or less, breakage starting from the top of the recess hardly occurs.

[0017] In one embodiment, in the laser processing step, a joining texture made of dross may be formed in the laser non-irradiated portion. In this case, the flow path resistance of the joining portion further increases, and the airtightness further improves.

[0018] In one embodiment, in the laser processing step, a joining texture made of an oxide may be formed in the laser non-irradiated portion. In this case, the flow path resistance of the joining portion further increases, and the airtightness further improves.

[0019] In one embodiment, the material of the metal member may be iron, copper, or aluminum. In this case, since iron, copper, and aluminum are materials that are easy to laser-process, a laser processing surface for joining can be efficiently formed.

[0020] In one embodiment, the material of the resin member may be a thermoplastic resin. In this case, by bringing the thermoplastic resin into contact with the surface of the metal member in a heated state, the resin can be filled into the recesses formed on the surface of the metal member.

[0021] According to another aspect of the present disclosure, a composite member is provided. The composite member includes a metal member having a plurality of recesses with an inner surface having a surface roughness of 20 nm or more and 1000 nm or less provided on its surface, and a resin member in direct contact with the surface of the metal member provided with the plurality of recesses.

[0022] In this composite member, a plurality of recesses that contribute to the anchor effect and the flow path resistance of the joining portion are provided on the surface of the metal member. The plurality of recesses have an inner surface with a surface roughness of 20 nm or more and 1000 nm or less. When the surface roughness is 20 nm or more, the surface area of the metal member increases. Thereby, the anchor effect is improved and the flow path resistance of the joining portion increases. When the surface roughness is 1000 nm or less, the fillability of the resin member into the recesses is improved. Thereby, the anchor effect is improved and the flow path resistance of the joining portion increases. From the above, a joining member having excellent joining strength and airtightness can be provided.

[0023] In one embodiment, in a cross-section orthogonal to the surface of the metal member, the metal member may have spherical metals spaced apart from the inner surface and surrounded by a resin member at a density of 4 or more and 50 or less per mm. In this case, by setting it to 4 or more per mm, the bonding strength and airtightness are further improved. By setting it to 50 or less per mm, the filling property into the concave portion of the resin member is improved.

Effects of the Invention

[0024] According to one aspect and embodiment of the present disclosure, there are provided a method for manufacturing a composite member having excellent bonding strength and airtightness and a composite member.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Mode for Carrying Out the Invention

[0026] Hereinafter, embodiments will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions are omitted. Also, in this embodiment, the "bonding strength" will be described as the "shearing strength".

[0027] [Composite member] FIG. 1 is a perspective view showing a composite member 1 according to an embodiment. As shown in FIG. 1, the composite member 1 includes a metal member 2 and a resin member 3. The composite member 1 is a member in which the metal member 2 and the resin member 3 are integrated by bonding. The metal member 2 and the resin member 3 are, as an example, plate-shaped members respectively. The resin member 3 is in direct contact with the surface 2a of the metal member 2. In FIG. 1, the resin member 3 is in direct contact with a part of the surface of the metal member 2 (contact surface 4 of the metal member 2) and has an overlapping joint structure.

[0028] The material of the metal member 2 is, for example, iron, copper, or aluminum. The material of the resin member 3 is, for example, a thermoplastic resin such as polyphenylene sulfide (PPS), polypropylene (PP), polyphthalamide (PPA), polybutylene terephthalate (PBT), polyamide (PA), acrylonitrile-butadiene-styrene (ABS), or polyetheretherketone (PEEK).

[0029] Figure 2 is a cross-sectional view of the composite member 1 along the line II-II in Figure 1. As shown in Figure 2, the metal member 2 is provided with a plurality of recesses 5 on a part (contact surface 4) of its surface 2a. The recess 5 has an inner surface 5a with a surface roughness (Ra) of 20 nm or more and 1000 nm or less, more preferably 20 nm or more and 500 nm or less. The surface roughness of the inner surface 5a is the line roughness conforming to JIS B0601:1994 / 2001. The surface roughness of the inner surface 5a is rougher than the surface roughness of the part of the surface 2a where the recess 5 is not provided.

[0030] The surface roughness of the inner surface 5a is measured, for example, by image analysis of a micrograph of the cross-section of the composite member 1. The cross-section of the composite member 1 is created, for example, by an ion milling device. Cutting with a grinding wheel or cross-section processing with a laser gives thermal influence and mechanical damage to the composite member 1. According to ion milling, the thermal influence and mechanical damage given to the composite member 1 can be suppressed. As the ion milling device, for example, IB-19500CP manufactured by JEOL Ltd. can be used. The surface roughness of the inner surface 5a may be measured, for example, by a white light interference microscope after removing the resin member 3.

[0031] As the white light interference microscope, for example, IS-R100 manufactured by Shin-Tech Precision Co., Ltd. can be used. As a method for removing the resin member 3, for example, a method of dissolving it with a solvent can be used. For example, when the material of the resin member 3 is polyamide, a solvent such as aniline or ethylene chlorohydrin is used. As another method for removing the resin member 3, a method of decomposing and removing it by atmospheric pressure plasma can also be used.

[0032] The depth of the recess 5 is 15 μm or more and 60 μm or less, more preferably 20 μm or more and 55 μm or less. The depth of the recess 5 is determined as the average value of the maximum depths, that is, the depth at the deepest position of each recess 5 with respect to the surface 2a as a reference plane. The depth of the recess 5 can also be determined by image analysis of a micrograph of the cross-section of the composite member 1. The depth of the recess 5 may be measured, for example, with a white light interference microscope after removing the resin member 3.

[0033] The plurality of recesses 5 are arranged at a pitch A. The plurality of recesses 5 are arranged via the wall portions 6. In this example, the height of the wall portion 6 is equal to the height of the surface 2a. The wall portion 6 has the surface 2a as its top. The pitch A is, for example, 20 μm or more and 150 μm or less. The pitch A is the center-to-center distance between a pair of adjacent recesses 5.

[0034] A part of the resin member 3 is joined to the metal member 2 in a state where it has entered the recess 5. Such a structure is formed, for example, by injection molding. The composite member 1 may be joined by a method other than injection molding, for example, press molding, vibration bonding, or ultrasonic bonding.

[0035] FIG. 3 is a photographic view showing an example of the cross-section of the composite member 1 (Test Example 21 described later). As shown in FIG. 3, in a cross-section orthogonal to the surface 2a (see FIG. 1), the metal member 2 has a spherical metal 2b spaced apart from the inner surface 5a of the recess 5 and surrounded by the resin member 3 therearound. The spherical metal 2b appears to be completely surrounded by the resin member 3 in cross-section, but is actually connected to the inner surface 5a and is part of the metal member 2. The metal member 2 has the spherical metal 2b at a density of 4 pieces / mm or more and 50 pieces / mm or less in a cross-section orthogonal to the surface 2a. The density of the spherical metal 2b is defined as the number of spherical metal 2b per unit length (1 mm) in the direction parallel to the surface 2a in a cross-section orthogonal to the surface 2a.

[0036] As described above, in the composite member 1 according to the present embodiment, a plurality of recesses 5 that contribute to the anchor effect and the flow path resistance of the joint are provided on the surface 2a of the metal member 2 that is in direct contact with the resin member 3. The plurality of recesses 5 have an inner surface 5a with a surface roughness of 20 nm or more and 1000 nm or less. Since the surface roughness is 20 μm or more, the surface area of the joint portion of the metal member 2 increases. As a result, when the molten resin member 3 flows into the recess 5 and is welded to the metal member 2, the anchor effect is improved and the flow path resistance of the joint portion increases. Since the surface roughness is 1000 μm or less, the filling property of the resin member 3 into the recess 5 is improved. As a result, the anchor effect is improved and the flow path resistance of the joint portion increases. From the above, it is possible to provide the composite member 1 having excellent joint strength and airtightness.

[0037] In a cross section orthogonal to the surface 2a, the metal member 2 has spherical metals 2b at a density of 4 pieces / mm or more. Since the spherical metals 2b are connected to the inner surface 5a of the recess 5, the anchor effect is exhibited. Therefore, the joint strength and airtightness are further improved. By setting the density to 50 pieces / mm or less, the filling property of the resin member 3 into the recess 5 is improved.

[0038] The material of the metal member 2 is, for example, iron, copper, or aluminum. Since iron, copper, and aluminum are materials that are easy to laser process, a laser processing surface for joining can be efficiently formed. The material of the resin member 3 is a thermoplastic resin. By bringing the thermoplastic resin into contact with the laser processed surface of the metal member 2 in a heated state, the resin can be filled into the recess 5 formed on the surface 2a of the metal member 2. According to the joint interface formed by the resin being transferred into the surface roughness of the inner surface 5a of the recess 5, the anchor effect is exerted and high shear strength can be obtained. As a method for transferring the resin, there are methods such as injection molding or press molding using a heated mold.

[0039] [Manufacturing method of composite member] FIG. 4 is a flowchart of a manufacturing method MT of the composite member 1 according to the embodiment. As shown in FIG. 4, the manufacturing method MT includes a preparation step S10, a laser processing step S12, and a bonding step S14. First, a metal member 2 is prepared as the preparation step S10. Subsequently, a laser processing step S12 of laser-processing the surface 2a of the prepared metal member 2 is performed. Finally, a bonding step S14 of directly bonding the resin member 3 to the surface 2a of the laser-processed metal member 2 is performed. Hereinafter, details of the laser processing step S12 and the bonding step S14 will be described.

[0040] [Laser Processing Step] In the laser processing step S12, for example, a pulsed laser is used. FIG. 5 is a cross-sectional view of the metal member 2 laser-processed in the laser processing step S12 according to the embodiment. FIGS. 6 to 9 are photographic views showing an example of the surface 2a of the metal member 2. The photographic view of FIG. 6 is an example of the surface of a metal member made of copper (JIS: C1020) (Test Example 1 described later). The photographic views of FIGS. 7 and 8 are examples of the surfaces of metal members made of iron (JIS: SPCC) (Test Examples 9 and 13 described later), respectively. The photographic view of FIG. 9 is an example of the surface of a metal member made of aluminum (JIS: A5052) (Test Example 23 described later).

[0041] The laser processing step S12 forms a plurality of recesses 5 on the surface 2a of the metal member 2 as shown in FIGS. 5 to 9. As described above, the surface roughness of the inner surface 5a of the recess 5 is 20 nm or more and 1000 nm or less, more preferably 20 nm or more and 500 nm or less. The surface roughness of the inner surface 5a is adjusted by the irradiation conditions of the laser. The surface roughness of the inner surface 5a can be measured, for example, by a white interference microscope or image analysis of a cross-sectional microscope photograph, in the same manner as in the case of the composite member 1. The cross-section of the metal member 2 is created by the same method as the cross-section of the composite member 1.

[0042] The depth of the recess 5 is, as described above, 15 μm or more and 60 μm or less, more preferably 20 μm or more and 55 μm or less. The depth of the recess 5 is adjusted according to the laser irradiation conditions. The depth of the recess 5 can be measured, for example, by a white interference microscope or image analysis of a cross-sectional micrograph, in the same manner as in the composite member 1.

[0043] In the laser processing step S12, a plurality of dot-shaped recesses 5 are formed by a pulsed laser. In the laser processing step S2, the plurality of recesses 5 are formed at a density of 40% or more and 100% or less. The plurality of recesses 5 are, in plan view (when viewed from a direction orthogonal to the surface 2a), for example, circular (see FIGS. 6, 7, and 9) or rectangular (see FIG. 8). The width A1 of the recess 5 is, for example, 20 μm or more and 150 μm or less. The width A1 of the recess 5 is the diameter of the recess 5 in the case of a circular recess 5 and the length of one side of the recess 5 in the case of a rectangular recess 5.

[0044] In the laser processing step S12, the plurality of recesses 5 are arranged at a pitch A that is 1 time or more and 2 times or less the spot diameter of the laser. For example, when the spot diameter of the laser is 50 μm, the pitch A is 50 μm or more and 100 μm or less. In the examples shown in FIGS. 6 to 9, the plurality of recesses 5 are arranged in a lattice or matrix pattern, and the pitch A is the same in the vertical and horizontal directions, but the pitch A may be different in the vertical and horizontal directions. The plurality of recesses 5 may be arranged in a staggered pattern or randomly.

[0045] Referring to FIGS. 10 and 11, a method for forming the rectangular recess 5 will be described. FIG. 10 is a diagram for explaining the relationship between the diameter B of the circular recess formed alone and the pitch A. The diameter B is larger than the spot diameter of the normal laser. FIG. 11 is an example of a plan view of the metal member 2 in which the rectangular recess 5 is formed. As shown in FIG. 10, since the diameter B of the single recess indicated by the broken line is larger than the pitch A (B > A), a recess 5 having a shape different from that of the single recess is formed. Between the adjacent recesses 5, a wall portion 6 lower than the surface 2a which is a non-irradiated portion is formed. In this example, it can be said that the laser processing step S12 arranges the plurality of recesses 5 via the wall portion 6 lower than the surface 2a. The depth C of the wall portion 6 is the depth with respect to the surface 2a. The wall portion 6 is lower than the surface 2a by the depth C. In this example, the plurality of recesses 5 can be arranged at a high density without gaps.

[0046] As shown in FIG. 11, the plurality of rectangular recesses 5 are arranged in a lattice pattern at the pitch A. The single recess is circular as indicated by the broken line. Since the diameter B of the single recess is larger than the pitch A (B > A), the rectangular recess 5 is formed. Here, since the pitch A is equal in the vertical and horizontal directions, the recess 5 is square. When the pitch A is different in the vertical and horizontal directions, the recess 5 is rectangular. In plan view, the wall portion 6 is linear and constitutes the four sides of the recess 5. The width A1 of the recess 5 is equal to the distance between a pair of adjacent wall portions 6. When B > A, the width A1 approaches the pitch A infinitely (A1 ≒ A).

[0047] FIG. 12 is a cross-sectional view when the diameter B of a single recess is smaller than the pitch A. At this time, the diameter B is equal to the width A1 of the recess 5 (B = A1). As shown in FIG. 12, between adjacent recesses 5, a wall portion 6 having a surface 2a, which is a non-irradiated portion, as a top is formed. In this example, it can be said that in the laser processing step S12, a plurality of recesses 5 are arranged via a wall portion 6 having a surface 2a of the metal member 2 as a top. In this configuration, on the joint surface with the resin member 3, there is no sharp convex portion that becomes a crack starting point of the resin member 3. Therefore, the resin member 3 is suppressed from cracking. In particular, it is effective for hard and brittle types of resins in which cracks are likely to progress. When the diameter B is less than or equal to the pitch A (B ≦ A), the smaller the pitch A, the larger the surface area of the metal member 2, so the connection strength, adhesion, and airtightness are improved.

[0048] FIG. 13 is a cross-sectional view for explaining the inclination angle θ of the inner surface 5a of the recess 5. The inclination angle θ is defined as the angle formed by a virtual line L1 indicating 50% depth of the recess 5 and a straight line L2 in a cross-section orthogonal to the surface 2a of the metal member 2. The straight line L2 is a straight line connecting an intersection point P between the inner surface 5a and the virtual line L1 and the topmost portion 5t of the recess 5. The 50% depth of the recess 5 is obtained as a relative value based on the 100% depth and 0% depth defined below. The virtual line L1 is a straight line parallel to the surface 2a and is set for each recess 5.

[0049] The 100% depth of the recess 5 is the depth of the bottommost portion 5b of the recess 5 in a cross-section orthogonal to the surface 2a. The bottommost portion 5b of the recess 5 is the portion where the depth from the surface 2a is the deepest in a cross-section orthogonal to the surface 2a. The 0% depth of the recess 5 is the depth of the topmost portion 5t of the recess 5 in a cross-section orthogonal to the surface 2a. The topmost portion 5t of the recess 5 is the portion where the height from the bottommost portion 5b is the highest in a cross-section orthogonal to the surface 2a. That is, in a cross-section orthogonal to the surface 2a, the higher one of the tops of the left and right wall surfaces forming the recess 5 is the topmost portion 5t. The height of the topmost portion 5t is equal to or lower than the surface 2a.

[0050] FIG. 14 is a cross-sectional view when the inclination angle θ of the inner surface 5a of the concave portion 5 is greater than 80 degrees. Thus, when the inclination angle θ is greater than 80 degrees, the apex 5t is more likely to be the starting point of fracture than when the inclination angle θ is 80 degrees or less. In FIG. 14, only the single concave portion 5 is shown, but when comparing the difference in the brittleness of the apex 5t due to the inclination angle θ, it is necessary to make the conditions other than the inclination angle θ, such as the width of the apex 5t, the same.

[0051] In the laser processing step S12, a joining texture made of dross (see FIG. 7) or oxide (see FIG. 8) may be formed in the non-laser-irradiated portion by laser irradiation. The dross is grains of metal scattered by laser irradiation. According to the dross, since the surface area of the metal member 2 increases, the joining strength between the metal member 2 and the resin member 3 is improved, the flow path resistance of the joint portion increases, and the airtightness is improved. The oxide is what the grains of metal scattered by laser irradiation are oxidized by high heat. According to the oxide, since the surface area of the metal member 2 increases more than that of the dross, the joining strength is further improved, the flow path resistance of the joint portion further increases, and the airtightness is further improved. These joining textures can be formed by adjusting the laser processing conditions.

[0052] [Joining Step] As the joining step S14, for example, injection molding is performed. Here, insert molding is performed. In insert molding, an insert is mounted in a predetermined mold, resin is injected, held for a predetermined time, and cured. Then, the residual stress of the resin is removed by heat treatment. In addition to injection molding as the joining step S14, for example, press molding, vibration joining, or ultrasonic joining may be performed.

[0053] FIG. 15 is a top view of a mold used for injection molding. FIG. 16 is a cross-sectional view of the mold taken along line XVI-XVI of FIG. 15. As shown in FIGS. 15 and 16, the mold 20 includes a mold body 21 (an upper mold 21a and a lower mold 21b). Between the upper mold 21a and the lower mold 21b, there are provided a space 22 for mounting an insert (here, a metal member 2) and a space 23 into which resin is injected. A resin injection port is provided on the upper surface of the upper mold 21a. The resin injection port communicates with the space 23 via a sprue 24, a runner 25, and a gate 26. A pressure sensor 27 and a temperature sensor 28 are provided in the space 23, and the pressure and temperature in the space 23 are detected. Based on the detection results of the pressure sensor 27 and the temperature sensor 28, parameters of a molding machine (not shown) are adjusted to manufacture a molded product. The parameters include mold temperature, resin temperature during filling, filling pressure, injection rate, holding time, pressure during holding, heat treatment temperature, heat treatment time, and the like. The molded product molded by the mold 20 has an overlapping joint structure that joins at a predetermined area.

[0054] A molding machine (not shown) performs molding using the above-described mold 20 as a joining step S14. First, the mold 20 is opened, the metal member 2 is mounted in the space 22, and the mold 20 is closed. Then, the molding machine injects molten resin having a set resin temperature into the inside of the mold 20 from the resin injection port. The injected resin passes through the sprue 24, the runner 25, and the gate 26 and fills the space 23. The molding machine controls the filling pressure and injection rate of the resin based on the detection result of the pressure sensor 27. The molding machine controls the mold temperature to reach a set value based on the detection result of the temperature sensor 28. Also, the molding machine controls the pressure to reach a set value during a set holding time based on the detection result of the pressure sensor 27. Thereafter, the molding machine performs heat treatment based on the set heat treatment temperature and heat treatment time. Thereafter, the molding machine opens the mold 20 and takes out the composite member 1 in which the metal member 2 and the resin member 3 are integrated. When the joining step S14 is completed, the flowchart shown in FIG. 4 is completed. Thereby, the composite member 1 shown in FIG. 1 is manufactured.

[0055] As described above, according to the manufacturing method MT, the surface 2a of the metal member 2 is laser processed. On the surface 2a of the metal member 2 after laser processing, a plurality of recesses 5 that contribute to the anchor effect and the flow path resistance of the joint portion are formed. The plurality of recesses 5 have an inner surface 5a with a surface roughness of 20 nm or more and 1000 nm or less. Since the surface roughness is 20 μm or more, the surface area of the metal member 2 increases. As a result, the anchor effect is improved, the flow path of the joint portion becomes complicated, and the flow path resistance increases. Since the surface roughness is 1000 μm or less, the filling property of the resin member 3 into the recess 5 is improved. As a result, the anchor effect is improved and the flow path resistance of the joint portion increases. From the above, it is possible to provide a manufacturing method of the composite member 1 having excellent bonding strength and airtightness.

[0056] The depth of the plurality of recesses 5 is 15 μm or more and 60 μm or less. Since the depth of the recess 5 is 15 μm or more, the surface area of the metal member 2 further increases and the flow path resistance of the joint portion further increases. Since the depth of the recess 5 is 60 μm or less, the time required for the laser processing step L2 is shortened and the productivity is improved. In addition, the filling property of the resin member 3 into the recess 5 is further improved.

[0057] In the laser processing step L2, a plurality of dot-shaped recesses 5 are formed by pulsed laser. For this reason, the surface area of the metal member 2 further increases. The recess 5 is circular or rectangular in plan view. In the case of the circular recess 5, the area of the bonding interface becomes large and the length of the flow path of the bonding interface can be increased, so the flow path resistance can be increased. In the case of the rectangular recess 5, the area of the bonding interface is even larger than in the case of the circular recess 5. Moreover, in the case of the rectangular recess 5, since the flow path at the interface bends at a right angle, the flow path resistance can be further increased compared to the case of the circular recess where the flow path at the interface gently bends along the circle.

[0058] The width A1 of the recess 5 is 20 μm or more and 150 μm or less. FIG. 17 is a diagram for explaining the relationship between the width of the recess and the area of the region receiving the shearing force. The width A1 of the recess 5 shown in FIG. 17(a) is larger than the width A1 of the recess 5 shown in FIG. 17(b). The arrow F indicates the direction of the shearing force. Among the inner surfaces 5a of the recess 5, the region receiving the shearing force is the hatched region. As understood from FIGS. 17(a) and 17(b), the smaller the width A1, the larger the total value of the area of the region receiving the shearing force can be. Thereby, the bonding strength can be improved. On the other hand, if the width A1 is too small, good filling of the resin member is hindered.

[0059] In the laser processing step L2, a plurality of recesses 5 are formed at a density of 40% or more and 100% or less. Since the density of the recesses 5 is 40% or more, the surface area of the metal member 2 further increases. The density of the recesses 5 may be 60% or less. By setting the density of the recesses 5 to 60% or less, the time required for the laser processing step is shortened and the productivity is improved.

[0060] In the laser processing step L2, a plurality of recesses 5 are arranged at a pitch of 1 times or more and 2 times or less the spot diameter of the laser. The diameter of the actually formed recess 5 is usually larger than the spot diameter of the laser. Therefore, according to this configuration, a plurality of recesses 5 can be efficiently arranged.

[0061] In the laser processing step L2, a plurality of recesses 5 are formed such that the inclination angle θ of the inner surface 5a is 40 degrees or more and 80 degrees or less. Since the inclination angle θ is 40 degrees or more, the flow path resistance of the joint is further increased so that a pressure loss of the fluid occurs, and the airtightness is further improved. Since the inclination angle θ is 80 degrees or less, it is difficult for breakage starting from the top 5t of the recess 5 to occur.

[0062] As described above, the present embodiment has been described. However, the present invention is not limited to the above-described present embodiment, and it goes without saying that various modifications can be made without departing from the gist thereof other than the present embodiment.

[0063] [Modification Example of Laser Processing Step] The laser processing step S12 may form continuous groove-shaped recesses 5. Also in this case, the surface roughness of the inner surface 5a of the recess 5 is 20 nm or more and 1000 nm or less. The continuous groove-shaped recesses 5 may be formed by a pulsed laser. In this case, damage to the metal member 2 can be reduced. Also, it is easy to control the processing depth (depth of the recess 5) and the surface roughness of the inner surface 5a of the recess 5. Furthermore, when a metal oxide film is formed on the surface of the metal member 2 after processing, oxygen atoms on the surface and the resin material form hydrogen bonds. In laser processing, although the metal surface is likely to be oxidized because it becomes hot compared to metal processing such as machining and blasting, oxidation of the metal surface can be suppressed by using a pulsed laser. In the laser processing step S12, a plurality of groove-shaped recesses 5 may be arranged at a pitch that is 1 time or more and 2 times or less the spot diameter of the laser.

[0064] [Modification Examples of Base Material and Resin Member] As the metal member 2 and the resin member 3 according to the above embodiment, a plate-shaped member has been shown as an example, but the present invention is not limited to this shape, and any shape that can contact each other can be adopted. The resin member 3 according to the above embodiment was in contact with a part of the surface of the metal member 2, but may be in contact with the entire surface of the metal member 2.

[0065] [Modification Example of Injection Molding] Injection molding is not limited to insert molding, and outser molding may be used.

Examples

[0066] Hereinafter, examples and comparative examples will be described in order to explain the effects of the embodiment. Note that the present disclosure is not limited to these examples.

[0067] An overlay test piece conforming to ISO19095-2:2015 was prepared as follows. First, a plurality of metal members made of copper (JIS: C1020), iron (JIS: SPCC), and aluminum (JIS: A5052) were prepared. The size of the metal member was 10 mm × 45 mm × 1.5 mm.

[0068] Subsequently, a plurality of dot-shaped recesses were formed on the surface of each metal member by laser processing using a pulsed laser. For the laser processing, a laser cleaning machine manufactured by Shinato S Precision Co., Ltd. was used. The output of the laser was 200 W, the wavelength was 1065 nm, and the spot diameter of the laser was 50 μm. The processing time was 30 seconds / cm 2 as follows. Here, by changing conditions such as the scanning pitch of the laser, the number of pulses, and the processing time, a plurality of types of metal members with different surface shapes were created for each of the materials copper, iron, and aluminum.

[0069] The surface shape of the laser-processed metal member was measured before the bonding process. For the measurement, a white interference microscope IS-R100 manufactured by Shinato S Precision Co., Ltd. was used. Specifically, the surface shape of the metal member is the depth of the recess, the width of the recess, the density of the recesses, the pitch of the recesses, the surface roughness of the inner surface of the recesses, and the inclination angle of the recesses. The inclination angle of the recesses was measured by image analysis of a microscopic photograph of the cross-section of the test piece. The cross-section of the test piece was created using an ion milling device IB-19500CP manufactured by JEOL Ltd. The depth of the recess, the width of the recess, the pitch of the recesses, the surface roughness of the inner surface of the recesses, and the inclination angle of the recesses were determined as the average value of the values obtained by measuring at least 5% or more of the recesses formed in the joint portion. Here, 5% to 10% of the number of recesses were measured. That is, when the number of recesses formed in the joint portion was 20,000, 1,000 to 2,000 recesses were measured and the average value was determined.

[0070] Subsequently, using the bonding device shown in FIGS. 15 and 16, a resin member was bonded to the laser-processed surface of each metal member. The material of the resin member was polyphenylene sulfide (PPS). The mold temperature was 140°C, the resin temperature was 270°C, the filling pressure was 60 MPa, and the injection rate was 64.2 cm 3 / s. During holding, the holding pressure was 40 MPa and the holding time was 8 s. During heat treatment, the heat treatment temperature was 130 °C and the heat treatment time was 2 h. Through this process, resin members were joined to each metal member, and test pieces 1 to 29 of the composite member were obtained. In test pieces 1 to 6, the metal member was made of copper. In test pieces 7 to 19, the metal member was made of iron. In test pieces 20 to 29, the metal member was made of aluminum.

[0071] Next, the airtightness and shear strength of the obtained composite member were evaluated. The evaluation of airtightness was performed by a helium leak test in accordance with ISO19095-3:2015. The evaluation of shear strength was performed by a method in accordance with ISO19095-2:2015.

[0072] Table 1 is a table showing the measurement results of the surface shape of the metal member, the evaluation results of airtightness, and the evaluation results of shear strength in test pieces 1 to 29. In Table 1, as the surface shape of the metal member, the depth of the concave portion, the width of the concave portion, the density of the concave portion, the pitch of the concave portion, the surface roughness of the inner surface of the concave portion, and the inclination angle of the concave portion are respectively shown. The evaluation result of airtightness is that when the leakage amount of the helium leak test is less than 5×10 -7 Pa·m 3 / s, it is indicated as "A", and when the leakage amount is 5×10 -7 Pa·m 3 / s or more, it is indicated as "B". The evaluation result of shear strength is that when the shear strength is 30 MPa or more, it is indicated as "A", when the shear strength is 20 MPa or more and less than 30 MPa, it is indicated as "B", when the shear strength is less than 20 MPa, it is indicated as "C", and when it is not joined, it is indicated as "D".

[0073]

Table 1

[0074] Among Test Examples 1 to 6 where the metal member is made of copper (JIS: C1020), the airtightness and shear strength were high in Test Pieces 1 and 2. In Test Piece 6, the resin member did not bond. In Test Piece 6, the density of the concave portion was only 2.8%, and the surface area of the metal member was too small, so it is considered that the resin member did not bond. In Test Pieces 3 to 5, the leakage amount was 5×10 -7 Pa·m 3 / s or more, and the shear strength was less than 20 MPa. In Test Pieces 3 to 5, the density of the concave portion was less than 40%, and it is considered that the surface area of the metal member was still insufficient.

[0075] Among Test Examples 7 to 19 where the metal member is made of iron (JIS: SPCC), the airtightness and shear strength were high in Test Pieces 8 to 14. In Test Pieces 18 and 19, the resin member did not bond. In Test Piece 18, since the surface roughness of the inner surface of the concave portion exceeded 1200 nm, the filling property of the resin member into the concave portion deteriorated, and it is considered that the resin member did not bond. In Test Piece 19, the density of the concave portion was only 5.2%, and the surface area of the metal member was too small, so it is considered that the resin member did not bond.

[0076] In Test Pieces 15 and 17, the leakage amount was 5×10 -7 Pa·m 3 / s or more, and the shear strength was less than 20 MPa. In Test Pieces 15 and 17, the density of the concave portion was less than 40%, and it is considered that the surface area of the metal member was insufficient. In Test Piece 7, the leakage amount was 5×10 -7 Pa·m 3 / s or more, and the shear strength was less than 30 MPa. In Test Piece 7, since the depth of the concave portion was less than 15 μm, the flow path resistance of the connection portion was low, and as a result, it is considered that the airtightness was low. In Test Piece 16, the leakage amount was 5×10 -7 Pa·m 3 / s or more. In Test Piece 16, since the depth of the concave portion exceeded 60 μm, the filling property of the resin member into the concave portion became insufficient, and it is considered that the airtightness was low.

[0077] Among Test Examples 20 to 29 where the metal member is made of aluminum (JIS: A5052), in Test Specimens 20 to 24, the airtightness and shear strength increased. In Test Specimens 28 and 29, the resin member did not bond. In Test Specimen 28, since the surface roughness of the inner surface of the concave portion exceeded 1600 nm, it is considered that the filling property of the resin member into the concave portion deteriorated. Moreover, in Test Specimen 28, the density of the concave portion was only 6.1%, and it is considered that the surface area of the metal member was too small. In Test Specimen 29, since the surface roughness of the inner surface of the concave portion exceeded 2000 nm, it is considered that the filling property of the resin member into the concave portion deteriorated. Moreover, in Test Specimen 29, since the depth of the concave portion was less than 15 μm, it is considered that the resin member did not bond sufficiently.

[0078] In Test Specimens 25 to 27, the leakage amount was 5×10 -7 Pa·m 3 / s or more. In Test Specimens 26 and 27, the shear strength was less than 20 MPa. In Test Specimens 26 and 27, the density of the concave portion was less than 40%, and it is considered that the surface area of the metal member was insufficient. Moreover, in Test Specimen 26, since the surface roughness of the inner surface of the concave portion exceeded 1000 nm, it is considered that the filling property of the resin member into the concave portion deteriorated. In Test Specimen 25, since the depth of the concave portion exceeded 60 μm, it is considered that, compared with Test Examples 20 to 24, the filling property of the resin member into the concave portion was insufficient, and the airtightness and shear strength decreased.

[0079] It was confirmed that in Test Examples 18, 26, 28, and 29 where the surface roughness of the inner surface of the concave portion exceeded 1000 nm, the airtightness and shear strength were not sufficiently ensured. It was also confirmed that in Test Examples 3 to 6, 15, 17 to 19, and 26 to 28 where the density of the concave portion was less than 40%, the airtightness and shear strength were not sufficiently ensured.

Explanation of Reference Signs

[0080] 1... Composite member, 2... Metal member, 2a... Surface, 2b... Spherical metal, 5... Concave portion, 5a... Inner surface, 6... Wall portion, A... Pitch, θ... Inclination angle.

Claims

1. A method for manufacturing a composite member in which a metal member and a resin member are joined, comprising the steps of: a laser processing step of laser processing a surface of the metal member; a joining step of directly joining the resin member to the surface of the metal member that has been laser-processed; Including, The laser processing step includes forming a plurality of recesses having an inner surface with a surface roughness of 20 nm to 1000 nm and a depth of 15 μm to 60 μm in a density of 40% to 100% in the surface of the metal member, The material of the metal member is copper or aluminum, The laser processing step is a method for manufacturing a composite member, in which a joining texture made of dross or oxide is formed in the non-laser irradiated portion.

2. The method for manufacturing a composite member according to claim 1 , wherein the laser processing step forms the plurality of dot-shaped recesses with a pulsed laser.

3. The method for manufacturing a composite member according to claim 2 , wherein the plurality of recesses are circular or rectangular in plan view.

4. The method for manufacturing a composite member according to claim 2 or 3, wherein the plurality of recesses have a width of 20 μm or more and 150 μm or less.

5. The method for manufacturing a composite member according to claim 1 , wherein the laser processing step forms the plurality of recesses each having a continuous groove shape with a pulsed laser.

6. 6. The method for manufacturing a composite member according to claim 1, wherein the laser processing step arranges the plurality of recesses at a pitch that is equal to or greater than 1 time and equal to or less than 2 times a laser spot diameter.

7. The method for manufacturing a composite member according to any one of claims 1 to 6, wherein the laser processing step arranges the plurality of recesses via a wall portion that is lower than the surface of the metal member.

8. The method for manufacturing a composite member according to any one of claims 1 to 6, wherein the laser processing step arranges the plurality of recesses via a wall portion having a top portion on the surface of the metal member.

9. The method for manufacturing a composite member according to any one of claims 1 to 8, wherein the laser processing step forms the plurality of recesses so that an inclination angle of the inner surface is 40 degrees or more and 80 degrees or less.

10. The method for manufacturing a composite member according to any one of claims 1 to 9, wherein the material of the resin member is a thermoplastic resin.

11. A metal member having an inner surface with a surface roughness of 20 nm to 1000 nm and having a plurality of recesses with a depth of 15 μm to 60 μm provided on the surface at a density of 40% to 100%; a resin member in direct contact with a surface of the metal member on which the plurality of recesses are provided, The material of the metal member is copper or aluminum, In a cross section perpendicular to a surface of the metal member, the metal member has spherical metal particles spaced from the inner surface and surrounded by the resin member at a density of 4 particles / mm or more and 50 particles / mm or less, Helium leak test leakage amount is 5 x 10 －７ P.A.M. ３ / s, A composite member having a shear strength of 20 MPa or more.

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