阅读说明：本技术 激光照射装置及使用其的表面粗糙化处理方法 (Laser irradiation apparatus and surface roughening method using the same ) 是由 乡田哲也 渡边加名 木下雅章 于 2020-09-14 设计创作，主要内容包括：本发明提供一种激光照射装置及使用其的表面粗糙化处理方法,能够照射最适合于为了提高部件的表面的粘接性而进行该表面的粗糙化的激光光线,并且即使在使用激光二极管作为激光光线的光源的情况下,也能够减轻对该激光二极管造成的损伤。使以给定的时间间隔从激光照射装置(10)照射的激光光线(L)的一次照射相应量的波形由前半部(100)和后半部(104)构成,前半部(100)在照射开始时每单位时间的照射强度的增加率为最大,随着接近最大照射强度,每单位时间的照射强度的增加率逐渐变小,后半部(104)在该前半部(100)之后每单位时间的照射强度的减少率成为最大,随着照射强度接近基值电流,每单位时间的照射强度的减少率逐渐变小。(The invention provides a laser irradiation device and a surface roughening treatment method using the same, which can irradiate laser beams most suitable for roughening the surface of a component in order to improve the adhesion of the surface, and can reduce damage to a laser diode even when the laser diode is used as a light source of the laser beams. A waveform corresponding to one shot of a laser beam (L) irradiated from a laser irradiation device (10) at a predetermined time interval is constituted by a first half part (100) and a second half part (104), wherein the rate of increase of irradiation intensity per unit time at the start of irradiation of the first half part (100) is maximized, the rate of increase of irradiation intensity per unit time gradually decreases as the irradiation intensity approaches the maximum irradiation intensity, the rate of decrease of irradiation intensity per unit time after the first half part (100) of the second half part (104) becomes maximized, and the rate of decrease of irradiation intensity per unit time gradually decreases as the irradiation intensity approaches a base current.)

1. A laser irradiation apparatus for improving the adhesion of a surface of a member by irradiating the surface with a laser beam to roughen the surface,

the laser light is irradiated at given time intervals,

the waveform of the laser light corresponding to one irradiation has:

a first half portion in which an increasing rate of the irradiation intensity per unit time is maximum at the start of irradiation, and the increasing rate of the irradiation intensity per unit time gradually decreases as the maximum irradiation intensity approaches; and

and a second half portion in which a rate of decrease in the irradiation intensity per unit time after the first half portion is maximized, and the rate of decrease in the irradiation intensity per unit time gradually decreases as the irradiation intensity approaches the base current.

2. The laser irradiation apparatus according to claim 1,

the waveform of the laser light corresponding to one shot also has a middle portion between the front half portion and the rear half portion where the rate of increase in shot intensity is close to zero.

3. A surface roughening treatment method for improving adhesion of a carbon fiber-reinforced plastic material by irradiating a surface of the carbon fiber-reinforced plastic material with a laser beam using the laser irradiation apparatus according to claim 1 or 2.

4. The surface roughening treatment method according to claim 3,

irradiating a plurality of the laser beams in a row,

irradiating the carbon fiber reinforced plastic material with the laser beam at a predetermined time interval while moving the laser irradiation device in a direction orthogonal to the irradiation line of the laser beam,

when the length of the concave portion formed by irradiating the laser beam in the moving direction is a major axis and the interval between the concave portions adjacent to each other in the moving direction is a longitudinal interval dimension,

the ratio of the longitudinal interval dimension to the major axis is 25% to 800%.

Technical Field

The present invention relates to a laser irradiation apparatus for roughening a surface of a member to improve adhesion of the surface, and a surface roughening treatment method using the laser irradiation apparatus.

Background

When bonding members using an adhesive, as a pretreatment, a treatment for roughening the surface of the member is generally performed. This "roughening" treatment generally uses a method such as a method using sandpaper, sandblasting, water spraying, or chemical treatment.

However, such methods have the following problems: the use of sandpaper causes quality variation due to contact, sandblasting causes problems in working environment due to dust, and water discharge equipment is required for water spraying or chemical treatment.

Therefore, in order to solve these problems, roughening treatment using a laser beam has been developed which can suppress quality variation by non-contact, has no problem in working environment, and does not require a drainage facility.

For example, patent document 1 has developed a technique for roughening a surface of a member such as a metal by irradiating the surface with a short-wavelength or long-wavelength laser beam.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 62-103317

Disclosure of Invention

Problems to be solved by the invention

However, when the surface of a member is roughened in order to improve the adhesiveness of the surface of the member, if the intensity of the laser beam is merely increased or the number of laser beams irradiated per unit area on the surface is merely increased, the adhesiveness of the surface is not necessarily improved, and may be rather reduced.

In addition, simply increasing the intensity of the laser beam may damage the laser diode that generates the laser beam.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a laser irradiation apparatus capable of irradiating a laser beam most suitable for roughening a surface of a member to improve adhesion of the surface, and reducing damage to a laser diode even when the laser diode is used as a light source of the laser beam, and a surface roughening treatment method using the laser irradiation apparatus.

Means for solving the problems

In accordance with one aspect of the present invention,

provided is a laser irradiation device which increases the adhesiveness of the surface of a member by irradiating the surface with a laser beam to roughen the surface,

the laser light is irradiated at given time intervals,

the waveform of the laser light corresponding to one irradiation has:

a first half portion in which an increasing rate of the irradiation intensity per unit time is maximum at the start of irradiation, and the increasing rate of the irradiation intensity per unit time gradually decreases as the maximum irradiation intensity approaches; and

and a second half portion in which a rate of decrease in the irradiation intensity per unit time after the first half portion is maximized, and the rate of decrease in the irradiation intensity per unit time gradually decreases as the irradiation intensity approaches the base current.

Preferably, the first and second electrodes are formed of a metal,

the waveform of the laser light corresponding to one shot also has a middle portion between the front half portion and the rear half portion where the rate of increase in shot intensity is close to zero.

In accordance with another aspect of the present invention,

provided is a surface roughening method for improving the adhesion of a CFRP material by irradiating the surface of the CFRP material with a laser beam using the laser irradiation apparatus.

Preferably, the first and second electrodes are formed of a metal,

irradiating a plurality of the laser beams in a row,

irradiating the CFRP material with the laser beam at predetermined time intervals while moving the laser irradiation device in a direction orthogonal to the irradiation line of the laser beam,

when the length of the concave portion formed by irradiating the laser beam in the moving direction is a major axis and the interval between the concave portions adjacent to each other in the moving direction is a longitudinal interval dimension,

the ratio of the longitudinal interval dimension to the major axis is 25% to 800%.

Effects of the invention

According to the present invention, after the irradiation intensity is rapidly increased in the first half of the irradiation of the surface of the member with the laser beam, the rate of increase in the irradiation intensity is gradually decreased, and the irradiation intensity is rapidly decreased in the second half of the irradiation. Thus, as shown in fig. 3, the concave portion formed on the surface of the member at the position irradiated with the laser beam has the following cross-sectional shape: the center portion of the recess has a deep bottom portion and is gently inclined toward the bottom portion.

By providing the recess formed on the surface of the member with the inclined portion gently inclined toward the bottom of the recess in the cross-sectional shape, the adhesive agent can easily flow into the bottom of the recess even when the surface of the member is coated with the adhesive agent having a relatively high viscosity as compared with, for example, the recess formed with the rectangular-wave laser beam (see fig. 5) having the substantially rectangular-shaped cross-sectional shape when the rectangular-wave laser beam (see fig. 4) is used. Therefore, the adhesiveness of the surface of the member can be improved.

Further, since the rate of increase in the irradiation intensity is gradually reduced in the first half of the irradiation, the occurrence of a spike current due to a rapid increase in the current intensity can be avoided, and therefore, even when a laser diode is used as the light source of the laser beam, damage to the laser diode can be reduced.

Drawings

Fig. 1 is a diagram showing a laser irradiation device 10 according to an embodiment to which the present invention is applied.

Fig. 2 is a diagram showing a waveform of a laser beam L to which an embodiment of the present invention is applied.

Fig. 3 is a cross-sectional view of a member S showing the shape of a recess X formed by applying a laser beam L according to an embodiment of the present invention.

Fig. 4 is a diagram showing a waveform of a rectangular-wave laser beam.

Fig. 5 is a cross-sectional view of the member S showing the shape of the recess formed by the rectangular-wave laser beam.

Fig. 6 is a diagram showing the laser irradiation device 10 according to modification 1.

Fig. 7 is a plan view of a member S showing a large number of concave portions X formed by the laser irradiation device 10 according to modification 1.

Fig. 8 is a graph showing a relationship between a longitudinal interval size and an adhesive strength.

Detailed Description

(Structure of laser irradiation device 10)

Hereinafter, the structure of the laser irradiation device 10 to which the present invention is applied will be described with reference to the drawings. The laser irradiation device 10 to which the present invention is applied can be used for roughening the surface T of a CFRP (carbon fiber reinforced plastic) material S as in the present embodiment, but is not limited to the CFRP material, and can also be used for roughening the surface of a metal or other member.

As shown in fig. 1, the laser irradiation device 10 is roughly provided with a laser light source 12 and a condenser 14.

The laser light source 12 is a member that generates a laser beam L of a predetermined wavelength and waveform, and in the present embodiment, a laser diode (semiconductor laser) is used. Of course, the laser light source 12 is not limited to this, and for example, a laser processing machine that can generate a laser beam L with a higher output may be used.

The light collector 14 is a member for collecting the laser beam L from the laser light source 12 to a predetermined focal position F, and in the present embodiment, two convex lenses 16 are combined for one laser light source 12. The focal position F is set on the surface T of the member S (CFRP material in the present embodiment) to be roughened. The light collector 14 is not limited to the light collector of the present embodiment, and the light collector 14 may be configured by using a reflector or a combination of a lens and a reflector, for example.

The laser beam L emitted from the laser light source 12 is refracted by the condenser 14 and focused on the surface T of the member S as a focal position F.

Here, the waveform of the laser beam L irradiated from the laser light source 12 will be described in detail. As shown in fig. 2, the waveform of the laser beam L is formed in a pulse shape. One concave portion X is formed on the surface T of the part S in one pulse period in which the current value is increased from the base current B and then decreased again to the base current B. Each pulse period is generated at a predetermined time interval, and the laser beam L is irradiated in each pulse period. The current value of the base current B may be zero or may be a predetermined current value larger than zero.

The waveform of the laser beam L according to the present embodiment has, with attention paid to the primary pulse period: a first half 100 in which the rate of increase of the irradiation intensity (current intensity) per unit time at the start of irradiation is the maximum, and the rate of increase of the irradiation intensity (current intensity) per unit time becomes smaller as the irradiation intensity approaches the maximum irradiation intensity (maximum current intensity); an intermediate portion 102 in which the rate of increase in irradiation intensity (current intensity) is close to zero; and a second half 104 in which the rate of decrease in the irradiation intensity (current intensity) per unit time after the intermediate portion 102 is maximized, and the decrease in the irradiation intensity (current intensity) per unit time decreases as the irradiation intensity (current intensity) approaches the base current B.

In the entire description, "the rate of increase in the irradiation intensity (current intensity) in the intermediate portion 102 is close to zero" means that the rate of increase is 10% or less when the maximum rate of increase in the irradiation intensity (current intensity) per unit time at the start of irradiation is 100%.

The intermediate portion 102 in the waveform of the laser beam L is not an essential configuration of the present invention, and the laser beam L may be constituted by the first half portion 100 and the second half portion 104.

According to the present embodiment, after the irradiation intensity (current intensity) is rapidly increased in the first half of the irradiation of the laser beam L to the surface T of the member S, the rate of increase in the irradiation intensity (current intensity) is gradually decreased, and in the second half of the irradiation, the irradiation intensity (current intensity) is rapidly decreased. As a result, as shown in fig. 3, the recess X formed on the surface T of the member S at the position irradiated with the laser beam L has the following cross-sectional shape: the center of the recess X has a deep bottom Z and is gently inclined toward the bottom Z.

As described above, the cross-sectional shape of the recess X formed on the surface T of the member S has the inclined portion K gently inclined toward the bottom portion Z of the recess X, and thus even when the adhesive Y having a relatively high viscosity is applied to the surface of the member, the adhesive Y is likely to flow into the bottom portion Z of the recess X, as compared with, for example, a recess having a substantially rectangular cross-sectional shape (see fig. 5) formed when a rectangular laser beam (see fig. 4) is used. Therefore, the adhesiveness of the surface T of the member S can be improved.

In addition, as described above, in the case where the laser beam L is formed by the first half 100 and the second half 104, the cross-sectional shape of the concave portion X formed by the laser beam L is a shape in which the length of the bottom portion Z in the width direction is short (or the bottom portion Z is almost absent and the concave portion X is formed only by the gentle inclined portion K), but even in this case, the cross-sectional shape of the concave portion X has the gently inclined portion K, and therefore, the adhesiveness of the surface T of the member S is improved, and the case where the bottom portion Z is present (that is, the waveform of the laser beam L has the intermediate portion 102) is more preferable from the viewpoint of improving the adhesiveness of the surface T of the member S.

Further, since the rate of increase in the irradiation intensity (current intensity) is gradually decreased in the first half of the irradiation, the occurrence of a spike current due to a rapid increase in the current intensity can be avoided, and therefore, even when a laser diode is used as the light source 12 of the laser beam L, damage to the laser diode can be reduced.

(modification 1)

In the above embodiment, the laser irradiation device 10 is configured by a set of the laser light source 12 and the condenser 14, but the laser irradiation device 10 may be configured by combining a plurality of the laser light sources 12 and the condensers 14.

As shown in fig. 6, the laser irradiation device 10 according to modification 1 is configured by combining 5 sets of the laser light source 12 and the light collector 14, for example.

The focal positions F of the laser beams L emitted from the laser light sources 12 toward the member S are set to be spaced apart by a predetermined interval and arranged in a line.

When the entire laser irradiation apparatus 10 is moved in a direction (hereinafter, referred to as a "longitudinal direction") orthogonal to the direction in which the focal positions F are arranged (hereinafter, referred to as a "width direction") and the laser beam L is irradiated at predetermined time intervals, the concave portions X can be formed in a checkered pattern on the surface T of the member S as shown in fig. 7.

(Experimental example)

When the laser irradiation apparatus 10 is used to irradiate the surface T of the CFRP material (member S) formed by aligning a large number of carbon fibers in parallel, a preferable longitudinal interval dimension is confirmed using the diameter of each recess X formed by each laser beam L, the width-direction interval dimension between the focal positions F of each laser beam L, and the longitudinal interval dimension as parameters. In addition, the direction in which the carbon fibers contained in the CFRP material (component S) extend and the "longitudinal direction" are aligned with each other.

The member S is fixed, and the laser irradiation device 10 irradiates the laser beam L having a pulse-like waveform at predetermined time intervals while moving in the longitudinal direction. Therefore, the surface shape of each concave portion X is an elliptical shape that is long in the vertical direction. Hereinafter, the longitudinal length of the surface shape of the recess X is referred to as "major axis", and the width-direction length is referred to as "minor axis".

In this experiment, the "major axis" was set to 0.1mm, and the "minor axis" was set to 0.05 mm. The adhesion strength of the CFRP material (member S) after the roughening treatment was confirmed by fixing the interval dimension in the width direction to 0.05mm and changing the interval dimension in the longitudinal direction.

The adhesion strength was measured by adhering the CFRP material (member S) to a 10mm diameter round stainless steel rod obtained by sandblasting the surface (#180, distance 10mm and 5 seconds) with an epoxy adhesive (Nagase Chemtex dentte XNR3324/XNH3324 (two-liquid type)), leaving the round rod at 100 ℃ for 0.5 hour, and then measuring the force (N) at which the round rod was peeled from the CFRP material (member S) by stretching. The experimental results are shown in table 1 and fig. 8.

[ TABLE 1 ]

The adhesion strength without roughening the surface of the CFRP material (component S) was 785.2N. As shown in the experimental results, if the interval dimension in the longitudinal direction is too short, the adhesion strength becomes small as compared with the case where the roughening treatment is not performed. Further, if the longitudinal interval is made longer, the adhesion strength is almost the same as that in the case where the roughening treatment is not performed, and the roughening treatment does not make sense.

Therefore, by setting the ratio of the longitudinal interval dimension to the major axis of the concave portion X to 25% to 800%, the adhesion strength can be improved as compared with the case where the roughening treatment is not performed.

Further, it is preferable to set the ratio of the longitudinal interval dimension to the major axis of the concave portion X to 50% or more and 650% or less, because the adhesion strength can be improved by 10% or more as compared with the case where the roughening treatment is not performed.

Further, it is more preferable to set the ratio of the longitudinal interval dimension to the major axis of the concave portion X to 75% or more and 450% or less, because the adhesion strength can be improved by 20% or more as compared with the case where the roughening treatment is not performed.

Further, as is clear from the results of other experiments, regarding the relationship between the width-direction interval dimension and the adhesive strength, if it is assumed that the width-direction interval dimension is larger than zero, the width-direction interval dimension does not affect the adhesive strength.

In addition, although the CFRP material S having the carbon fiber in one direction is used at this time, even when the CFRP material S in which the carbon fibers are woven in a plain or twill pattern in the vertical direction is used, the adhesion strength can be improved as long as the conditions at this time are satisfied.

The same applies to FRP materials using fiber materials other than carbon, for example, glass fibers, ceramic fibers, aramid fibers, aluminum fibers, cellulose nanofibers, and the like.

It is also understood that even if the directions of the major and minor diameters of the concave portions X are reversed, the relationship between the ratio of the vertical distance dimension to the "minor diameter" of the concave portions X and the adhesion strength is the same as the above relationship.

The embodiments disclosed herein are illustrative in all respects and should not be considered restrictive. The scope of the present invention is defined not by the above description but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Description of the symbols

10 … laser irradiation device, 12 … laser light source, 14 … light-gathering piece

100 … front half, 102 … middle part, 104 … back half

L … laser beam, F … focal position, S … (roughened) part, T … (of part S) surface, X … recess, B … background current, Y … adhesive, K … inclined portion.