JP3223206B2 - Light absorber for laser processing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a light absorber for laser processing used in, for example, infrared laser processing.

[0002]

2. Description of the Related Art Conventionally, as this kind of light absorber, a graphite coating formed on the surface of a workpiece has been known.

[0003]

However, when a portion to be processed having a graphite coating is subjected to infrared laser processing, graphite tends to be trapped in the portion to be processed, so that the characteristics of the portion change or the coating by coating is applied. However, there is a problem that it is difficult to improve the light absorbance by exhibiting uniform light absorbency over the whole because unevenness easily occurs.

[0004] In view of the above, the present invention relates to a light absorber having a relatively large degree of freedom in selecting a material, and capable of exhibiting a uniform light absorbency over the whole to improve the light absorbance. The purpose is to provide.

[0005]

The light absorber for laser processing according to the first aspect of the present invention is composed of an aggregate of metal crystals having a body-centered cubic structure, and the aggregate emits light on the (hhh) plane with a Miller index. A (hhh) oriented metal crystal that grows in a columnar shape toward the irradiation surface side and forms a pyramid on the light irradiation surface;
The (Shh) oriented metal crystal abundance S is S ≧ 40%
And the inclination angle θ of the (hhh) oriented metal crystal.
Characterized in that is 0 ° ≦ θ ≦ 30 °.

The light absorber according to the second invention is composed of an aggregate of metal crystals having a face-centered cubic structure, and the aggregate grows in a columnar shape with the Miller index toward the (3hhh) surface toward the light irradiation surface side. And form a pyramid on the light irradiation surface (3hh
h) containing an oriented metal crystal, the abundance S of the (3hhh) oriented metal crystal is S ≧ 40%, and the (3hhh)
hh) The inclination angle θ of the oriented metal crystal is 0 ° ≦ θ ≦ 30 °
There is a feature.

[0007]

[Function] (hhh) Oriented metal crystal and (3hhh)
The oriented metal crystal grows in a columnar shape and forms a pyramid on the order of microns on the light irradiation surface of the light absorber. When the oriented metal crystals having such a shape are present at the abundance S, the metal crystals can be uniformly dispersed throughout the light absorber.

In the light absorber, a part of the light (including visible light, infrared light, etc.) hitting the slopes of many fine pyramids is absorbed, and the other part is reflected. The incidence and reflection are repeated and the probability of light exiting the valley between the pyramids is extremely reduced, thereby improving the light absorption.

In the infrared laser processing, it is possible to select the material of the light absorber so that the material is not adversely affected even if it is taken in the processed part.

However, when the existence ratio S is S <40%,
As the abundance of the oriented metal crystals decreases, the light absorption rate significantly decreases.

[0011]

EXAMPLES In FIG. 1, the laser addition to the metal substrate 1
The working light absorber 2 is formed by plating. Light absorber 2
Is composed of an aggregate of metal crystals having a body-centered cubic structure (bcc structure), as shown in FIG. The aggregate has the (hhh) surface directed toward the light irradiation surface 3 by the Miller index (hh).
h) comprises oriented metal crystals 4 _1, Part (hhh) the content S of the oriented metal crystals 4 ₁ is set to S ≧ 40%.

[0012] (hhh) oriented metal crystals 4 ₁ grow in a columnar shape, the light irradiation surface 3 of the absorption body 2, forms a pyramid 4a of micron order. Having such a shape (hhh)
When the oriented metal crystal 4 ₁ is present at the existence ratio S,
Their metal crystals 4 ₁ can be uniformly dispersed throughout absorbing material 2.

In the light absorber 2, a part of the light L (including visible light, infrared light, etc.) hitting the slopes of the many fine pyramids 4a is absorbed, and the other part is reflected. The light hits the slope of the adjacent pyramid 4a, and the incidence and reflection are repeated, so that the probability that the light L is emitted from the valley between the pyramids 4a is extremely reduced, thereby improving the light absorption.

In infrared laser processing or the like, (h
hh) oriented metal crystals 4 ₁ material substrate 1, therefore it is possible to match or approximate to that of the workpiece.

[0015] As shown in FIG. 3, (hhh) oriented metal crystals 4 ₁ slope affects the extinction ratio. Therefore, a virtual surface a along the substrate 1 is defined on the bottom surface side of the pyramid 4a, and a straight line d passing through the vertex b and the bottom center portion c of the pyramid 4a passes through the bottom center portion c and is perpendicular to the virtual surface a. If the inclination angle with respect to the line e is defined as θ, the inclination angle θ is 0 ° ≦ θ ≦ 3.
It is set to 0 °. In this case, not limited for (hhh) oriented metal crystals 4 ₁ tilt direction. When the inclination angle θ is θ> 30 °, the amount of reflected light from the light absorber 2 increases, and the light absorption rate decreases.

As shown in FIG. 4, the light absorber 2 is also composed of an aggregate of metal crystals having a face-centered cubic structure (fcc structure). In this case, the aggregate is Miller index (3hhh)
Includes a surface facing the light irradiation surface 3 side (3hhh) oriented metal crystals 4 _2, Part (3hhh) the content S of the oriented metal crystals 4 ₂ is set to S ≧ 40%.

[0017] (3hhh) oriented metal crystal 4 _2, (h
hh) was grown in a columnar shape in the same manner as oriented metal crystals 4 _1, in the light irradiation surface 3 of the absorbing material 2, without the pyramidal 4a of micron order, therefore (hhh) oriented metal crystals 4 ₁
The same light absorption action as described above is performed. (3hhh) inclination angle of the oriented metal crystals 4 ₂ theta, the are likewise 0 ° ≦ θ ≦ 30 °, also not limited for its tilt direction.

As a metal crystal having a bcc structure, F
e, Cr, Mo, W, Ta, Zr, Nb, V, etc., or a crystal of a simple substance or alloy. The metal crystals having the fcc structure include Pb, Ni, Cu, Al, A
g, Au or the like, or a crystal of an alloy.

In the plating process for forming the light absorber 2 according to the present invention, the basic conditions for performing the electric Fe plating process are as shown in Tables 1 and 2.

[0020]

[Table 1] Urea, saccharin and the like are used as the organic additive.

[0021]

[Table 2] Tables 3 and 4 show the case of the electric Ni plating process.

[0022]

[Table 3]

[0023]

[Table 4] In the electric Fe and Ni plating treatment performed under the above conditions, the crystallization and the abundance of the oriented Fe and Ni crystals are controlled by the cathode current density, the plating bath pH, the amount of the organic additive, and the like.

As the plating process, in addition to the electroplating process, a vacuum plating process, for example, a vapor phase plating method (PVD method,
CVD method), sputtering method, ion plating and the like. Conditions for performing W and Mo plating by the sputtering method include, for example, Ar pressure 0.8 Pa, Ar
Acceleration power DC 1 kW, base material temperature 100 ° C. Conditions for performing Pt and Al plating by the sputtering method include, for example, an Ar pressure of 0.8 Pa, an Ar accelerating power of DC 5
00W, base material temperature 100 ° C. W by CVD method
Conditions for plating are, for example, raw material WF ₆ , gas flow rate 10 cc / min, chamber pressure 100 P
a, Base material temperature is 500 ° C. In addition, A
The conditions for performing the l-plating are, for example, the raw material Al (C
H ₃ ) ₃ , gas flow rate 2 cc / min, chamber pressure
The base material temperature is 100 ° C and the base material temperature is 500 ° C.

Hereinafter, specific examples will be described. Length 60
mm, width 25 mm, thickness 7 mm
The light absorber 2 composed of an aggregate of Fe crystals was formed by performing a plating process.

Tables 5 and 6 show the conditions for the electro-Fe plating in Examples 1 to 6 of the light absorber 2.

[0027]

[Table 5]

[0028]

[Table 6] Table 7 shows the crystal morphology of the light irradiation surface 3 in Examples 1 to 6, Fe
The crystal grain size and the abundance S of each oriented Fe crystal are shown.

[0029]

[Table 7] The abundance S is determined by the following method based on the X-ray diffraction diagrams of Examples 1 to 6 (the X-ray irradiation direction is a direction perpendicular to the light irradiation surface 3). As an example, Example 2 will be described. FIG. 5 is an X-ray diffraction diagram of Example 2, showing each orientation F
The e crystal abundance S was obtained from the following equation. Note that, for example, a {110} oriented Fe crystal means an oriented Fe crystal with the {110} plane facing the light irradiation surface 3 side. {110} oriented Fe crystal: S ₁₁₀ = {(I ₁₁₀ / IA)
₁₁₀ ) / T} × 100, {200} oriented Fe crystal: S ₂₀₀ = {(I ₂₀₀ / IA)
₂₀₀ ) / T} × 100, {211} oriented Fe crystal: S ₂₁₁ = {(I ₂₁₁ / IA)
₂₁₁ ) / T} × 100, {310} oriented Fe crystal: S ₃₁₀ = {(I ₃₁₀ / IA)
₃₁₀ ) / T} × 100, {222} oriented Fe crystal: S ₂₂₂ = {(I ₂₂₂ / IA)
₂₂₂ ) / T｝ × 100 where I ₁₁₀ , I ₂₀₀ , I ₂₁₁ , I ₃₁₀ , and I ₂₂₂ are the measured values (cps) of the X-ray reflection intensity of each crystal plane, and IA ₁₁₀ , IA ₂₀₀ , and IA ₂₁₁ , IA ₃₁₀ and IA ₂₂₂ are the X-ray reflection intensity ratios of each crystal plane in the ASTM card,
IA ₁₁₀ = 100, IA ₂₀₀ = 20, IA ₂₁₁ = 30,
IA ₃₁₀ = 12 and IA ₂₂₂ = 6. Further, T is T
_{= (I 110 / IA 110)} + (I 200 / IA 200) + (I
_{211 / IA 211) + (I} 310 / IA 310) + (I 222 /
IA ₂₂₂ ).

FIG. 6 is a photomicrograph (5000 times) showing the crystal structure of the light-irradiated surface 3 in Example 2. 6, forming a plurality of substantially hexagonal pyramid shape (hhh) oriented Fe crystals 4 ₁ was observed, these Fe crystal 4 ₁ is uniformly dispersed throughout absorbing material 2. The (hhh) is oriented Fe crystal 4 ₁ which has been formed by the coalescence of the (hhh) plane, therefore the {222} plane and toward the light irradiation surface 3 side three pyramidal {222} oriented Fe crystals, the Hexagon pyramid {222}
As shown in Table 7 and FIG. 5, the abundance S of the oriented Fe crystal is S = 50.6%.

Next, the surface of the steel substrate 1 having a length of 60 mm, a width of 25 mm, and a thickness of 7 mm was subjected to an electric Ni plating treatment to form a light absorber 2 composed of an aggregate of Ni crystals.

Tables 8 and 9 show the conditions of the electric Ni plating treatment in Examples 7 to 11 of the light absorber 2.

[0033]

[Table 8]

[0034]

[Table 9] Table 10 shows the crystal morphology of the light irradiation surface 3 in Examples 7 to 11,
The particle size of the Ni crystal and the abundance S of each oriented Ni crystal are shown.

[0035]

[Table 10] The abundance S was determined by the same method as described above based on the X-ray diffraction diagrams of Examples 7 to 11 (the X-ray irradiation direction was a direction perpendicular to the light irradiation surface 3).

FIG. 7 is an X-ray diffraction diagram of Example 7. FIG. 8 is a micrograph (5) showing the crystal structure of the light irradiation surface 3 in Example 7.
000 times). 8, forms a large number of pyramidal (3hhh) oriented Ni crystals 4 ₂ is observed, these Ni crystal 4 ₂ is uniformly dispersed throughout absorbing material 2. The pyramidal (3hhh) oriented Ni crystals 4 _2,
The (3hhh) plane, and thus the {311} plane, is
It is a {311} oriented Ni crystal directed to the side, and its abundance S is 64.8% as shown in Table 10 and FIG.

Next, the following test was performed on the light absorbers 2 of Examples 1 to 11, and their light absorption coefficients were examined. The test is,
As shown in FIGS. 9 and 10, (a) the substrate 1 is placed on a movable plate (not shown) with the light absorber 2 facing upward, (b)
An infrared laser beam Lb having a wavelength of 10.6 μm is applied to the light absorber 2.
And absorb the light absorber 2 in the direction of the arrow with the substrate 1 at 2 m / mi.
n, and simultaneously move the infrared laser beam Lb meandering at a frequency f = 100 Hz within a range of width W = 5 mm. (c) Melting the light absorber 2 by changing the energy density of the infrared laser beam Lb The energy density at the start was determined.

FIG. 11 shows {222} in Examples 1 to 11.
The relationship between the abundance S of the oriented Fe crystal and the {311} oriented Ni crystal and the energy density at the start of melting is shown. Line x
₁ corresponds to Examples 1 to 6 having {222} oriented Fe crystals,
The line x ₂ Examples 7 having a {311} oriented Ni crystals
11 and points (1) to (11) correspond to Examples 1 to 1, respectively.
1 respectively.

From FIG. 11, lines x ₁ and x ₂ , if the abundance S of the {222} oriented Fe crystal and the {311} oriented Ni crystal in the light absorber 2 is set to S ≧ 40%, It can be seen that the energy density decreases, that is, the absorbance increases.

In FIG. 11, the energy density range E at the start of melting corresponds to the case where the surface of the steel substrate is subjected to surface roughening processing to improve the light absorption. The surface roughness of the surface of the substrate 1 is Rmax = 6.3 S, and the energy density is only 5.0 to 7.5 kW / cm ² . In contrast, Example 1
The surface roughness Rmax of the light absorber 2 having the {222} oriented Fe crystal of No. 3 is Rmax = 2.0 S, and the energy density is 3.0 kW / cm ^2. Ru significant improvement in the absorption rate is observed in comparison.

FIG. 12 shows the relationship between the tilt angle θ of the {222} oriented Fe crystal of Example 3 and the {311} oriented Ni crystal of Example 9 and the energy density at the start of melting. Line y _{1 corresponds} to Example 3 and line y ₂ corresponds to Example 9. From FIG. 12, it can be seen that if the tilt angle θ of the {222} -oriented Fe crystal and the {311} -oriented Ni crystal is in the range of 0 ° ≦ θ ≦ 30 °, the absorbance of the light absorber 2 is improved.

[0042]

[0043]

According to the present invention, with the structure described before reporting, it is possible to provide an excellent laser processing absorbance of absorptivity. Further , since this light absorber is composed of an aggregate of metal crystals, for example, in infrared laser processing, it is possible to select the material of the light absorber so as not to have any adverse effect even if it is taken into the processing target. Thus, it is possible to avoid a change in the characteristics of the processed portion.

[Brief description of the drawings]

FIG. 1 is a vertical side view of a substrate having a light absorber.

FIG. 2 is a perspective view showing a body-centered cubic structure and its (hhh) plane.

FIG. 3 is an explanatory diagram showing inclinations of (hhh) and (3hhh) oriented metal crystals.

FIG. 4 is a perspective view showing a face-centered cubic structure and its (3hhh) plane.

FIG. 5 is an X-ray diffraction diagram of an example of a light absorber.

FIG. 6 is a micrograph showing a crystal structure of a light irradiation surface in an example of a light absorber.

FIG. 7 is an X-ray diffraction diagram of another example of the light absorber.

FIG. 8 is a micrograph showing a crystal structure of a light irradiation surface in another example of the light absorber.

FIG. 9 is an explanatory diagram showing an absorbance measurement test method.

FIG. 10 is a view taken in the direction of arrow 10-10 in FIG. 9;

FIG. 11 shows a {222} oriented Fe crystal and {311}.
5 is a graph showing the relationship between the abundance of oriented Ni crystals and the energy density at the start of melting.

FIG. 12 shows {222} oriented Fe crystals and {311}.
5 is a graph showing the relationship between the inclination angle θ of an oriented Ni crystal and the energy density at the start of melting.

[Explanation of symbols]

2 absorbing material 3 light irradiation surface 4 ₁ (hhh) oriented metal crystals 4 ₂ (3hhh) oriented metal crystals

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Katsumune Tabata 1-4-1 Chuo, Wako-shi, Saitama Pref. Honda Technical Research Institute Co., Ltd. (56) References JP-A-2-122890 (JP, A) JP-A JP-A-54-153588 (JP, A) JP-A-53-31987 (JP, A) JP-A-3-215695 (JP, A) JP-A-3-215694 (JP, A) JP-A-61-30297 (JP, A) JP-A-56-1289 (JP, A) Patent 2724795 (JP, B2) Patent 2687076 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C25D 3/20 B23K 26 / 18 C25D 3/12

Claims (2)

(57) [Claims] 1. An aggregate of metal crystals having a body-centered cubic structure, wherein the aggregate grows in a columnar shape with the Miller index toward the (hh) plane toward the light irradiation surface (3), and comprises forming the pyramid on the light irradiation surface (3) (4a) (hhh) oriented metal crystals (4 _1), the content S of the (hhh) oriented metal crystals (4 ₁₎ is S ≧ 40% And the inclination angle θ of the (hhh) -oriented metal crystal (4 ₁ ) is 0 °.
≦ θ ≦ 30 °, an absorber for laser processing. 2. An aggregate of metal crystals having a face-centered cubic structure, wherein the aggregate has a Miller index of (3hhh).
The surface grows in a columnar shape toward the light irradiation surface (3) and forms a pyramid (4a) on the light irradiation surface (3) (3hh).
h) containing an oriented metal crystal (4 ₂ ), (3hhh)
Characterized in that the content S of the oriented metal crystals (4 ₂₎ is S ≧ 40%, also the inclination angle theta of the (3hhh) oriented metal crystals (4 ₂₎ is 0 ° ≦ θ ≦ 30 ° Absorber for laser processing.