JP2007222891A - Method of joining metallic member for glasses - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for joining metallic members for glasses each other without dulling them, and to provide a method for easily joining metallic members for glasses of a Ti-based metallic material with sufficient joining strength without deforming the members. <P>SOLUTION: The joint of a first metallic member 1 for glasses and a second metallic member 2 for glasses is irradiated with a laser, so as to be welded. Further, the energy density of the laser is 350 to 3,000 J/cm<SP>2</SP>. Besides, by performing second welding in which the energy density of the laser is reduced after the welding, a metallic structure of forming a beat is diffused, thus the beat can be removed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a technique for joining metal members for glasses.
More specifically, the present invention relates to a method for joining spectacle metal members using laser welding when joining titanium spectacle members.

When manufacturing eyeglasses, when metal members are bonded to each other, bonding by brazing is mainly performed.
Brazing is a kind of metal member joining method, and is a technique for joining members by melting them using a metal having a melting point lower than that of the metal of the joining member called “brazing”.
In other words, it melts the wax, infiltrates the brazed member by capillarity, and applies wettability that spreads over the member. Unlike welding, it can melt the joint of the member to be joined. Absent.
The conditions capable of brazing are that the brazing material exhibits good wettability on the surface of the member, and it can be said that any material can be used as long as this condition is satisfied.

JP 2000-288755 A

However, when the metal member for spectacles is joined by brazing, since the metal member for spectacles generally joined is thin, the heat of the heated brazing is easily transmitted to the metal member for spectacles.
For this reason, the said spectacles metal member becomes blunt and softened by the heat | fever of a wax.
For this reason, even if it becomes dull and softened, it is necessary to secure the necessary and sufficient rigidity as a member for spectacles. Result.

Recently, metal materials that do not cause an allergic reaction even when used (contacted) by metal allergic patients have been developed, and one of them is a Ti-based metal material (a general term for metals containing Ti) that is a material for eyeglass members. It is also used as.
Then, when brazing a spectacle member made of a Ti-based metal material having a low thermal conductivity, it is common to braze using spot welding capable of heating the Ti-based metal material to a high temperature.

However, in order to perform spot welding, it is necessary to create electrodes that match the shape of the eyeglass members to be joined. Creating electrodes for each lot of different sizes and shapes requires extra man-hours. It was.
Further, in spot welding, from the viewpoint of improving energy efficiency, the electrode is pressed against the spectacle member, and a voltage is applied while eliminating air corresponding to the high electric resistor from the gap between the electrode and the spectacle member as much as possible. The operation was being performed.
However, the force at the time of press contact is considerably large to apply to the spectacle member (usually 260 MPa to 400 MPa), and the spectacle member is often deformed during welding because the spectacle member is heated and softened. Occurred.

Further, during spot welding, the glasses member made of Ti metal material forms an oxide film on the surface, and the presence of the oxide film prevents the glasses member from coming into contact with each other. Was difficult.
For this reason, it has been common to indirectly bond glasses members made of Ti-based metal materials by applying nickel plating to the surfaces of glasses materials made of Ti-based metal materials and joining the nickel plating and the solder.
However, the bonding strength of the part that is actually bonded depends on the strength of the nickel plating part that is extremely thin, and the nickel plating is easy to peel off, so the bonding force is very weak.

The present invention has been made against the background of the above technical problems.
That is, the present invention provides a method for joining spectacle metal members without dulling and a method for joining Ti metal metal spectacle metal members easily with sufficient joining force without deforming the members. The purpose is to do.

  In view of the background of the problems as described above, the inventor has conducted extensive research and found that the problem can be solved by using laser welding for joining the metal members for spectacles, and the present invention has been completed based on the findings. It has been made.

  That is, the present invention is (1) a method for welding two metal members for spectacles, and a method for joining spectacle metal members for performing welding by irradiating a laser to a joint portion of metal members for both spectacles. Exist.

  Moreover, this invention exists in the joining method of the metal member for spectacles of the said (1) description whose at least one of the metal member for glasses (2) is Ti or Ti alloy.

The present invention also relates to (3), the energy density of the laser is 300 J / cm ² or more and 3000 J / cm ² or less above (2) consists in the joining method of the ophthalmic metal member according.

  Moreover, this invention exists in the joining method of the metal member for ophthalmic glasses of the said (2) description which lowers | hangs the energy density of a laser and performs 2nd welding after welding.

  Moreover, this invention exists in the joining method of the metal member for spectacles of the said (4) description whose energy density in the case of (5) 2nd welding is 10 to 30% of the energy density of 1st welding. .

  Moreover, this invention exists in the joining method of the metal member for spectacles of the said (2) description which chamfers the junction part of the metal member for both spectacles to (6) taper shape.

  The present invention is also directed to (7), the metal for glasses according to (2), wherein the laser output waveform is a pulse waveform, and the pulse waveform is a waveform in which the laser output rises and falls stepwise. It exists in the joining method of a member.

  Further, the present invention is (8) the spectacle metal according to (2) above, wherein the laser output waveform is a pulse waveform, and the pulse waveform is a waveform in which the laser output continuously rises and falls. It exists in the joining method of a member.

  In addition, as long as the objective of this invention is met, the structure which combined suitably the invention from said (1)-(8) is also employable.

According to the present invention, welding can be instantaneously completed by using laser welding for joining the metal members for glasses.
As a result, almost no heat is transmitted to the vicinity of the joint portion of the spectacle metal member, and the spectacle metal member is not dulled or softened.
As a result, the elasticity of the entire spectacle metal member is not lost, and there is no need to thicken the joint portion in advance in order to ensure elasticity as in the prior art.
As a result, the entire spectacles can be designed with a more free idea without being limited in design as a spectacle metal member.

In addition, when a Ti-based metal material is used as the material for the spectacle metal member, the spectacle metal members are directly joined to each other, so there is no need to create an electrode as in conventional spot welding, and until the welding is completed. Man-hours can be reduced.
Further, since it is not necessary to apply pressure to the metal member for spectacles, the member is not deformed during spot welding.
Furthermore, since it is not indirect joining using nickel plating, the joining force is also necessary and sufficient.

The present invention uses laser welding as a method of joining spectacle metal members together.
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In the laser welding method of the present invention, two metal members for eyeglasses are butted together and laser is irradiated to the entire joined portion so as to perform welding.
In the present invention, the type of laser (for example, CO ₂ laser, YAG laser, excimer laser, etc.) is not particularly limited, and can be freely selected depending on the situation.
Note that a YAG laser is preferably used from the viewpoint of easy waveform control.
As the laser output waveform, it is preferable to use a pulse waveform output from the viewpoint of preventing the welding region from becoming large.

By the way, laser welding gives energy to the joint of two metal members for spectacles, heats that part to melt the metal, and when the molten metal cools and hardens, The principle that the organization is integrated is applied.
Accordingly, there is a correlation between the size of the area where the molten metal comes into contact with the surrounding spectacle metal member and the bonding strength.
That is, by irradiating a laser with a large output, it becomes possible to form a deep perforation groove in the spectacle metal member than when irradiating a laser with a low output. The contact area increases, and the bonding strength increases as compared with the case of irradiating a laser with a small output.

However, since the metal member for spectacles is extremely thin compared with a general steel material, the thermal influence on the metal structure around the joint becomes larger as the output of the laser is increased.
Therefore, by increasing the output and reducing the diameter of the laser beam (so-called “spot diameter”) and reducing the area of the portion irradiated with the laser beam as much as possible, the thermal effect on the metal structure around the joint is reduced. It needs to be reduced.
That is, by increasing the energy (energy density) per unit area, it is possible to realize both improvement of the bonding force and prevention of changes in the metal structure due to thermal effects.

In the present invention, the energy density range during laser welding is preferably 350 J / cm ² or more and 3000 J / cm ² or less.
When the energy density is smaller than 350 J / cm ^2, the bonding strength between the metal members for spectacles is insufficient, and when it is larger than 3000 J / cm ² , excessively large perforations are formed in the bonded portion, resulting in deterioration of the appearance.

By the way, the amount of heat generated by the laser is very large. In particular, the temperature at the center of the laser is well above the boiling point of the spectacle metal member, and the spectacle metal member begins to evaporate during welding.
As a result, the evaporated metal (sputter) jumps out of the perforated groove made by the laser due to its vapor pressure and adheres to the metal member for spectacles around the joint.
A so-called “spatter scattering phenomenon” occurs.
Due to this phenomenon, spatter adhesion marks remain in the vicinity of the joint, and the aesthetics at the time of finishing are impaired.

In order to prevent the occurrence of this spatter, laser welding is performed after chamfering the vicinity of the first spectacle metal member 1 and the second spectacle metal member 2 as shown in FIG. preferable.
Here, the chamfering means a state in which the joint line of the joint portion is the lowest position and both sides thereof are tapered.
As described above, according to the laser welding method of the present embodiment, it is possible to prevent spattering with a small kinetic energy as much as possible by welding the spectacle metal member at a position lower than the joining line.

Further, as described above, it is preferable that the output of the laser to be used has a pulse waveform, but in that case, it is possible to reduce spatter scattering by increasing the output rise gradually.
As a method of changing the rising of the output, there is a method of gradually increasing and decreasing the output until the laser output reaches a peak as shown in the laser output waveform shown in FIG.
As shown in the laser output waveform of FIG. 3, there is a method in which the output is continuously increased and decreased continuously until the laser output reaches a peak.

  By the way, as can be seen from FIG. 1, when welding is performed with a pulse waveform laser, a laser beam having a pulse waveform is sequentially applied and irradiated from the vertical direction along the joint, and the entire joint is dotted (P (Refer to the point) and weld so as to continue (first welding).

However, as shown in FIG. 1, unevenness due to molten metal, that is, a beat tends to remain in the welded portion at the periphery of the portion (welded portion) irradiated with the laser.
In the present invention, in order to flatten the beat of the weld and diffuse the metal structure forming the beat, the second welding is performed with an energy density smaller than the energy density of the first welding after the first welding. Is preferred.

In addition, the energy density in the second welding is 10% to 30% of the energy density in the first welding from the viewpoint of sufficiently removing the beat without newly generating a beat. Is more preferable.
When the second welding is performed at an energy density of less than 10%, the beat flattening and the metal structure cannot be sufficiently diffused. When the energy density is greater than 30%, a new beat is applied. May be expressed.

  Hereinafter, the present invention will be described with reference to specific examples. However, the present invention is not limited to the following examples without departing from the object of the present invention.

[Example 1]
Actually, laser welding is performed on a metal member for spectacles to prove its effectiveness. The implementation conditions are as follows.
A titanium long plate (length 40 mm, width 3 mm, thickness 2 mm) was used as a metal member for test glasses.
The welding machine used was a YAG laser welding machine, and the moving speed of the laser irradiation port was 1 mm / s.
The waveform of the YAG laser used was a pulse waveform with a pulse width of 1.5 msec, and the energy density of the laser was 2000 J / cm ² .
In addition, as a test for measuring the joining force (peeling strength) of the joining surface, a load parallel to the joining surface was applied to the welded portion, and the magnitude of the load when the welded portion broke was recorded.

In order to observe the state of the thermal effect on the metal structure around the joint after welding, it is cut perpendicular to the joint and its cross-sectional state is observed.
FIG. 4 shows a photograph of the cross-sectional state.
The peel strength was 277 MPa.

[Example 2]
The same procedure as in Example 1 was performed except that the energy density was 200 J / cm ² . A photograph of the cross section is shown in FIG.
The peel strength was 80 MPa. This peel strength is a bonding strength sufficient for spectacle parts.

Example 3
The same procedure as in Example 1 was performed except that the energy density was 4000 J / cm ² .
A photograph of the cross section is shown in FIG.
The peel strength was 350 MPa.

As can be seen from FIGS. 4 to 6, when the energy density of the laser is 350 J / cm ² or less, the energy density is insufficient, and a sufficient penetration depth cannot be obtained. In the case of 3000 J / cm ² or more, on the contrary, the penetration depth becomes too deep and perforations remain in the joint after welding, thereby deteriorating the appearance.

Example 4
All procedures were performed in the same manner as in Example 1 except that the joint portion of the metal members for both glasses was chamfered into a tapered shape and laser welding was performed.

7 is a photograph of the periphery of the joint after welding in Example 1, and FIG. 8 is a photograph of the periphery of the joint after welding in Example 4.
The white spots in the photograph are spatter. As can be seen from the two photographs, it can be seen that the spattering of the spatter is obviously reduced in the case where the joint portion of the metal member is chamfered in a tapered shape.

Example 5
After the members were welded under the same conditions as in Example 1, the energy density was set to 20% (267 J / cm ² ) of the energy density of Example 1, and second welding was performed on the welded portion.
The photograph of the welded part after the second welding is shown in FIG.

Example 6
After the members were welded under the same conditions as in Example 1, the energy density was set to 5% (70 J / cm ² ) of the energy density of Example 1, and second welding was performed on the welded portion.
A photograph of the welded portion after the second welding is shown in FIG.

As can be seen by comparing FIG. 7, FIG. 9, and FIG. 10, the beat is flattened and formed in the second welding rather than the one welding. It can be seen that the metal structure is diffused.
In particular, it can be seen that beats can be most reliably removed when the energy density of the second weld is 10% to 30% of the energy density of the first weld.

  Although the present invention has been described above, the present invention is not limited to the embodiments, and various modifications can be made.

FIG. 1 is a view showing a state in which an end portion of a spectacle metal member is chamfered in a tapered shape and welded. FIG. 2 is a diagram showing a waveform when the output of the laser is increased stepwise. FIG. 3 is a diagram showing a waveform when the laser output is continuously increased. FIG. 4 is a photograph of a cross-sectional state of the joint portion of Example 1. FIG. 5 is a photograph of the state of the cross section of the joint of Example 2. FIG. 6 is a photograph of a cross-sectional state of the joint portion of Example 3. FIG. 7 is a photograph of the situation around the joint portion of Example 1. FIG. 8 is a photograph of the situation around the joint in Example 4. FIG. 9 is a photograph of the appearance of the welded portion of Example 5. FIG. 10 is a photograph of the appearance of the welded part of Example 6.

Explanation of symbols

1 Metal member for glasses 2 Metal member for glasses 3 Laser irradiation device P Welded part

Claims (8)

  A method for welding two metal members for spectacles, wherein the welding is performed by irradiating a laser beam onto a joint portion between the metal members for both spectacles.   2. The method for joining spectacle metal members according to claim 1, wherein at least one of the spectacle metal members is Ti or a Ti alloy. 3. The method of joining spectacle metal members according to claim ² , wherein the energy density of the laser is 350 J / cm ² or more and 3000 J / cm ² or less.   3. The method for joining a metal member for spectacles according to claim 2, wherein after welding, the energy density of the laser is lowered to perform the second welding.   5. The method for joining spectacle metal members according to claim 4, wherein the energy density in the second welding is 10% to 30% of the energy density of the first welding.   3. The method of joining spectacle metal members according to claim 2, wherein the joint portion of both the spectacle metal members is chamfered in a tapered shape. The laser output waveform is a pulse waveform,
3. The method for joining a metal member for spectacles according to claim 2, wherein the pulse waveform is a waveform in which the output of the laser rises and falls stepwise. The laser output waveform is a pulse waveform,
3. The method of joining spectacle metal members according to claim 2, wherein the pulse waveform is a waveform in which the laser output continuously rises and falls.

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