JPS61102238A - Laser light irradiating device for joining synthetic resin material - Google Patents

Abstract

PURPOSE:To realize the unfirom heating and melting of synthetic resin material and at the same time prevent the uniform swelling-up of melt from developing by a method wherein laser light is made into a parallel beam with the predetermined diameter by means of a plurality of optical lenses and a probe, the tip form of which is of stepped conical, is employed for the forming of an eyelet form. CONSTITUTION:Laser light M incident from an optical fiber 2 is turned into laser light Ma with a divergence angle of beams theta from the incident part of an upper case 1a in order to strike a first optical lens 4a. By passing through the lens 4a, the light Ma is turned into parallel laser light Mb so as to strike a second optical lens 4b in order to be turned into laser light Mc, which has spherical wave surface and concentrates again, resulting in striking a third optical lens 4c and finally emitting in the form of parallel laser light Md. The tip part of a probe 7 is equipped with a stepped part 7a, from the underside of which a cone 7c is protrudingly formed. The size of the stepped part 7a is the one to engage with the tapered surface Wd of a convergent machined hole Wc formed on an upper synthetic resin material Wa. In addition, the laser light Md is guided by a cylindrical member 5 and transmitted by the probe 7 in order to irradiate a lower synthetic resin material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser beam irradiation device suitable for joining synthetic resin materials together.

[Conventional technology]

Conventionally, when joining synthetic resin materials, a physical joining method in which heat is applied to weld them, and a chemical joining method in which they are joined together using an adhesive have been widely used.

In other words, the former physical joining method generates heat with a heating element such as a metal mesh on the joint surfaces of the synthetic resin materials to be joined, melts the joint surfaces of both synthetic resin materials, pressurizes and cools them, and performs resynthesis. This is a method of joining resin materials. In addition, the latter chemical bonding method involves interposing an adhesive such as hot melt on the surfaces of the synthetic resin materials to be bonded, and applying high frequency or ultrasonic waves from the surface of one synthetic resin material. After heating and melting the two synthetic resin materials, the two synthetic resin materials are cooled while being pressurized, and the synthetic resin materials are rejoined.

However, in the former physical joining method, when joining the same type of synthetic resin materials, the melting temperature of the two synthetic resin materials to be joined is the same and they are compatible, so the re-synthetic resin material However, when joining different types of synthetic resin materials, the melting temperatures of the two synthetic resin materials are different and their compatibility is poor.
It is difficult to firmly bond resynthetic resin materials. In addition, the latter chemical bonding method is as suitable as the former physical bonding method when bonding synthetic resin materials of the same type, but it is suitable for bonding synthetic resin materials of different types. The adhesive force of the adhesive varies depending on the material, and it is difficult to firmly join both synthetic resin materials.

As a means of solving the above problem, the present inventors have proposed a method (Japanese Patent Application No. 5!172255) of bonding synthetic resin materials using laser light as shown in FIGS. 4 and 5.

In FIGS. 4 and 5, 5I is a plate member made of styrene-acrylonitrile copolymer reinforced by adding glass fiber, and the raw material color of this plate member 51 is black due to the addition of carbon blank. 1.
It has the property of absorbing laser light of 0.6 μm or less.

Further, a plate member 52 made of polypropylene resin is arranged on the upper part of the plate member 51, and a through hole 53 having a step is formed in the center thereof, and the thickness of the thin part 54 is 0.5 mm. 3 ms. The material color of this plate member 52 is black due to the addition of carbon blank, and has the property of absorbing laser light of 1.06 μm or less.

In addition, YAG: neodymium 3f laser irradiation nozzle 55
A cylindrical probe 56 made of polypropylene resin is provided at the tip of the probe 56, whose diameter is equal to that of the through hole 5 formed in the plate member 52 made of polypropylene resin.
The diameter is smaller than that of No. 3, and the outer periphery is partially covered with a vapor-deposited layer 57 of aluminum. The raw material color of the probe 56 is milky white, and has the property of not absorbing laser light of 1.06 μm or less.

Then, the plate member 51 is set as shown in FIG.
52, the probe 56 is moved near the upper side of the through hole 53 formed in the plate member 52, and its tip is positioned above the surface of the plate member 51. Next, YAG
:The wavelength is 1 from the irradiation nozzle 55 of the neodymium 1f laser.
．． 06 μm, output is 20 WYAG laser light. As a result, the YAG laser beam is transmitted to the cylindrical probe 56.
The light passes through the interior while being repeatedly reflected and refracted, and passes through the through hole 53 from the tip of the probe 56 to reach the surface of the plate member 51.

Then, the YAG laser light that reaches the plate member 51 is accumulated as energy at that location, and the surface of the plate member 51 is heated and melted by the energy. Then, after sufficiently melting the plate member 51, Y
While stopping the irradiation of the AG laser beam, the probe 56 is inserted through the through hole 53 as shown in FIG. 5, and its tip is pressed against the melted region. At that time, as the melt 51a of the plate member 51 is inserted into the probe 56, the through hole 5
3 and the probe 56, and the thin portion 54 of the through hole 53 is covered with the melt 51a.

After the thin wall portion 54 is covered by the melted material 51a, the probe 56 is pulled up and its tip is positioned above the plate member 52. As a result, the melt 51a of the plate member 51 is transferred to the through hole 53 formed in the plate member 52.
hardens while covering the thin wall portion 54 of both plate members 51.5.
2 are firmly joined.

[Problem that the invention seeks to solve]

However, in such a bonding method using laser light, the laser light that is irradiated onto the surface of the plate member 51 made of styrene-acrylonitrile copolymer is simply formed into a cylindrical shape from polypropylene resin, and aluminum is vapor-deposited N51 on the outer periphery of the cylindrical shape. Since the laser beam is irradiated through the probe 56 that forms the laser beam, it is difficult to keep the irradiation diameter of the laser beam constant, which not only causes uneven heating and melting of the plate member 51 to be melted. Both plate members 51.52
Since the eyelet shape of the probe 56 is cylindrical, the melt 5
There is a problem in that the shape of the bulge of 1a is uneven, and it is not possible to form an eyelet shape for strong bonding.

Therefore, this invention was made to solve the problem described in -E, and the laser beam irradiated onto the surface of the synthetic resin material is made into a predetermined parallel beam diameter using a plurality of optical lenses, and the eyelet shape is The purpose of this molding is to make the tip of the probe into a stepped conical shape to uniformly heat and melt the synthetic resin material and to prevent uneven bulges of the molten material.

[Means for solving problems]

That is, in the laser beam irradiation device for joining synthetic resin materials according to the present invention, an optical fiber for inputting the laser beam is connected to one end of the cylindrical body, and an optical fiber for guiding the input laser beam is connected to the other end of the cylindrical body. A cylindrical member is connected. In addition, a plurality of optical lenses are arranged at intervals inside the cylindrical body, so that the laser beam incident from the optical fiber is emitted into the cylindrical member as parallel rays of arbitrary diameter. ing.

Further, a probe made of a material through which laser light passes, such as quartz glass or polypropylene resin, is provided at the tip of the cylindrical member, and the tip is formed into a stepped conical shape. As a result, the bottom portion of the molten synthetic resin material bulges evenly, and both synthetic resin materials can be firmly joined.

As the synthetic resin material used during bonding, the synthetic resin material that does not absorb laser light is polyethylene,
These include vinyl chloride, polypropylene, styrene-acrylonitrile copolymer, phenol, polyacetal, etc. Synthetic resin materials that absorb laser light include polypropylene resin with auxiliary materials such as carbon blank added, and glass. Examples include styrene-acrylonitrile copolymers reinforced with fibers and added with carbon black. These synthetic resin materials can be freely selected and bonded in a combination such that at least the synthetic resin material disposed in the lower part has absorbency to laser light.

In addition, lasers used when bonding synthetic resin materials include glass: neodymium 3+ laser, YAG: neodymium 3+ laser, ruby laser, helium neon laser, krypton laser, argon laser, H2 laser,
Examples include N2 laser, among which YA laser
G: Neodymium 3+ laser is most suitable.

In addition, the wavelength of the laser used when joining synthetic resin materials needs to be a wavelength suitable for the synthetic resin materials to be joined, and a wavelength of 1.06 μm or less is excellent; It is impossible to melt and join synthetic resin materials.

In addition, a range of 5W to 100W is suitable for the laser output; if the output is less than 5W, the synthetic resin material cannot be melted, and if it is more than 100W, the synthetic resin material will evaporate. or deterioration, making it impossible to join.

[Effect]

In such a laser beam irradiation device for joining synthetic resin materials, when overlapping synthetic resin materials and joining them,
Of the synthetic resin materials to be overlapped, at least the lower synthetic resin material is made absorbent to laser light, and the upper synthetic resin material is formed with a machined hole, and the two are overlapped.

Next, the laser beam irradiation device is moved above the machined hole formed in the upper synthetic resin material, and the tip of the probe is inserted through the machined hole and brought into contact with the surface of the lower synthetic resin material.

Thereafter, a laser beam having a wavelength of 1.064 m or less and an output of 5 W to 100 W is input from the optical fiber, and is irradiated from the tip of the probe to the synthetic resin material below.

At that time, the laser beam travels through multiple optical lenses disposed inside the cylindrical body while repeatedly condensing and expanding, and the final optical lens converts the laser beam into a parallel beam. It passes through and reaches the synthetic resin material at the bottom, heating and melting that part.

Then, press the tip of the probe against the melted area. At this time, as the probe is inserted, the molten material of the synthetic resin material in the lower part bulges upward from the gap in the processed hole, and the stepped portion of the probe prevents the molten material from rising upward.

After a predetermined amount of the probe has been inserted, the laser beam irradiation is stopped and at the same time the probe is pulled up. As a result, the molten material in the lower part is hardened, and the synthetic resin materials disposed above and below are firmly joined.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a laser beam irradiation device for bonding synthetic resin materials according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a cross-sectional view of a laser beam irradiation device for bonding synthetic resin materials according to the present invention, FIG. 2 is an enlarged cross-sectional view of a portion joined by the laser beam irradiation device of the present invention, and FIG. 3 is a laser beam irradiation device of the present invention. FIG. 3 shows an enlarged front view of a probe used in the irradiation device.

In FIGS. 1 to 3, reference numeral 1 denotes a cylindrical body formed from a metal material, and this cylindrical body l
is divided into two parts, an upper case 1a and a lower case 1b, the upper case 1a is screwed into the lower case 1b, and both cases 1a and 1b have the same inner diameter. Further, an optical fiber 2 connected to a laser oscillator (not shown) is connected to the upper end of the case la of the F section composing this cylindrical body 1, and the laser beam transmitted from the laser oscillator is connected to the upper end of the case la. The light M is reflected within the core material 3 of the optical fiber 2 and enters the cylindrical body l.

Moreover, inside the cylindrical body 1, there are three optical lenses 4a, 4.
b, 4C are arranged with an interval.

That is, the first optical lens 4a is a convex lens, and
．． The second optical lens 4b is disposed near the lower end of the upper case 1a, and the second optical lens 4b is a convex lens, and is disposed approximately at the center of the lower case 1b. In addition, the third optical lens 4
C is a convex lens like the first optical lens 4a,
It is arranged near the lower end of the lower case 1b.

The laser light M entering from the optical fiber 2 becomes a laser light Ma having a spread angle θ from the entrance portion of the upper case 1a, and enters the first optical lens 4a. Further, the laser beam Ma incident on the first optical lens 4a becomes a parallel laser beam Mb and enters the second optical lens 4b, and then becomes a spherical laser beam Mc condensed at a certain focal point again. The light enters the optical lens 4C. Further, the spherical laser beam Me that has entered the third optical lens 4C is emitted again as a parallel laser beam Md. The diameter of the emitted laser beam Me can be arbitrarily changed by the combination of the second optical lens 4b and the third optical lens 4C.

Further, the lower case 1b constituting the cylindrical main body 1 is provided with a cylindrical member 5 made of a metal material. This cylindrical member 5 has a flange 5a formed at its upper end, and the flange 5a is brought into contact with the lower end of the lower case 1b.
It is held at "ζ" by the screwing of the fixing fitting 6.

Further, a probe 7 made of transparent quartz glass is fixed to the tip of the cylindrical member 5. The probe 7 is solid, and its upper outer diameter is the same as the outer diameter of the cylindrical member 5. Further, as shown in the enlarged view of FIG. 3, the tip of the probe 7 has a stepped portion 7a, and its lower surface 7b is formed into a conical shape 7C, and its lower surface 7d is formed flat. At the same time, the upper surface 7e is also formed flat. Further, the stepped portion 7 of the probe 7
a is a tapered surface Wd of a tapered machined hole Wc formed in the upper synthetic resin material Wa of the two synthetic resin materials Wa and Wb superimposed as shown in FIGS. 1 and 2.
The conical portion 70 has a smaller diameter than the machined hole We, and is sized to form a gap with the tapered surface Wd.

The parallel laser beam Md emitted from the third optical lens 4C of the cylindrical body 1 is guided by the cylindrical member 5 and reaches the probe 7, and in that state passes through the inside of the probe 7 and passes through the lower synthetic resin. The material is irradiated.

In the laser light irradiation device for joining synthetic resin materials configured as described above, a method for overlapping synthetic resin materials and joining them together will be described.

First, among the synthetic resin materials Wa and Wb to be joined, the synthetic resin material wb disposed at the bottom is made of styrene-acrylonitrile reinforced with glass fiber and carbon black that is absorbent to laser light is added. The synthetic resin material Wa disposed on the top was made of polypropylene resin, and a tapered processed hole We was formed in the center thereof.

Thereafter, both synthetic resin materials Wa and Wb are overlapped as shown in FIG.

Next, the processed hole Wc formed in the upper synthetic resin material Wa
The laser beam irradiation device is moved above the probe 7, and the tip of the probe 7 is inserted through the processed hole Wc to contact the surface of the synthetic resin material below. Next, from the W optical fiber 2, YAG with a wavelength of 1.06 μm and an output of 20 W: Neodymium 3
A laser beam M consisting of + is made to enter the cylindrical body 1, and is irradiated from the tip of the probe 7 to the synthetic resin material wb at the bottom.

At this time, the laser light M entering from the optical fiber 2 becomes the laser light Ma having a spread angle θ from the entrance part of the upper case la, and enters the first optical lens 4a.

Then, the laser beam M incident on the first optical lens 4a
a becomes parallel laser beam Mb and passes through the second optical lens 4b.
A spherical laser beam Mc enters and is condensed to a certain focal point.
The light then enters the third optical lens 4C. Further, the spherical laser beam Mc incident on the third optical lens 4c is emitted again as a parallel laser beam Md, and is emitted from the probe 7.
is irradiated from the tip to the lower synthetic resin material wb.

Then, the laser light that reached the synthetic resin material wb at the bottom,
The heat energy is accumulated in that part, and the synthetic resin material wb is quickly heated and melted by the heat energy. Then, while the synthetic resin material wb is melted by the laser beam Md, the tip of the probe 7 is pressed against the melted region. At this time, as shown in FIG. 2, as the probe 7 is inserted, the melt We of the synthetic resin material wb in the lower part swells upward through the gap in the machined hole We, and the stepped part 7a of the probe 7 moves into the machined hole. It comes into contact with the upper surface tapered portion Wd of the WC, and is pressed upward by the lower surface 7b, so that a part of the melt We covers the tapered portion Wd of the processed hole Wc formed in the upper synthetic resin material Wa.

] 5 Then, the tapered portion Wd of the machined hole Wc is formed by the melt We.
After the area is sufficiently covered, the irradiation of the laser beam M is stopped, and the rainbow probe 7 is pulled up to move its tip away from the upper synthetic resin material Wa. At this time, since the probe 7 is made of quartz glass in a metastable glass state, other
It is extremely bonded to the substance and can be easily pulled up without any adhesion of the molten material We. ′ □.

As a result, the melt We of the lower synthetic resin material wb hardens while covering the tapered part Wd of the processed hole Wc formed in the upper synthetic resin material Wa, and both synthetic resin materials Wa
, Wb are firmly bonded.

Further, the recessed portion Wf formed by the insertion of the probe 7 can be used as a screw starter when the bond between the two synthetic resin materials Wa and Wb is broken.

〔Effect of the invention〕

As explained above, in the laser beam irradiation device for joining synthetic resin materials according to the present invention, the laser beam irradiated onto the surface of the synthetic resin material is made to have a predetermined parallel beam diameter using a plurality of optical lenses. This has the effect of uniformly heating and melting the synthetic resin material.

Furthermore, in the laser beam irradiation device of the present invention, since the eyelet shape is formed using a probe having a stepped conical shape at the tip, it is possible to prevent uneven buildup of the molten material of the synthetic resin material. This has the effect of increasing the bonding strength.

In addition, in the laser beam irradiation device of the present invention, unlike conventional bonding methods, the melt of the synthetic resin material does not bulge or bulge on the top of the synthetic resin material above.
It is famous for its ability to improve the appearance after bonding.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a laser beam irradiation device for bonding synthetic resin materials according to the present invention. FIG. 2 is an enlarged sectional view of a portion joined by the laser beam irradiation device according to the present invention. FIG. 3 is an enlarged front view of a probe used in the laser beam irradiation device according to the present invention. FIG. 4 is a sectional view before joining in a conventional synthetic resin material joining method. FIG. 5 is a cross-sectional view at the time of joining in a conventional synthetic resin material joining method. 1, --- Tubular body 1a --- Upper case lb...- 111 Lower case 2-1 --- Optical fiber 3-- 11.-- Core material 4a --- -1 First optical lens 4b---1 Second optical lens 4cm---1 Third optical lens 5---Cylindrical member 5a---Flange 6---1 securing bracket? --- Probe 7 a --- Stepped portion 7 b --- One lower surface 1 cm -- One conical shape 7 d --- Lower surface 7 e --- One upper surface M --- Laser beam W a -----... Upper synthetic resin material w b ---
---・Lower synthetic resin material W c -------One processed hole W d ------Tapered part We---Melted material Wf-----Concave part Applicant Toyota Motor Corporation /CP-1'Tfomiπ2

Claims (1)

[Claims] An optical fiber for inputting laser light is connected to one end of the cylindrical body, a cylindrical member for guiding the incident laser beam is connected to the other end, and a plurality of optical lenses are arranged at intervals inside the cylindrical body. a probe made of a material through which laser light can pass is provided at the tip of the cylindrical member;
A laser beam irradiation device for joining synthetic resin materials, characterized in that the tip of the probe is formed into a stepped conical shape.