JPS6258901B2 - - 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 uses a heating element such as a metal mesh to generate heat on the joining surfaces of the synthetic resin materials to melt the joining surfaces of both synthetic resin materials while applying pressure and cooling. This is a method of joining resin materials. In addition, in the latter chemical bonding method, an adhesive such as hot melt is interposed on the joint surfaces of the synthetic resin materials to be bonded, and high frequency or ultrasonic waves are applied from the surface of one synthetic resin material to heat the adhesive. - After melting, both synthetic resin materials are cooled while being pressurized, and both synthetic resin materials are joined together.

However, in the former physical joining method, when joining synthetic resin materials of the same type, both synthetic resin materials have the same melting temperature and are compatible, so both synthetic resin materials are 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, so it is difficult to firmly join the two synthetic resin materials. Have difficulty. 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 differs depending on the material of the material, and it is difficult to firmly join both synthetic resin materials.

As a means of solving the above problem, the inventors have proposed a method of joining synthetic resin materials using laser light as shown in FIGS. 4 and 5 (Japanese Patent Application No. 72,255/1982).

In FIGS. 4 and 5, reference numeral 51 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 black. It has the property of absorbing laser light of 1.06 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 to 3 mm. is formed. The material color of this plate member 52 is black due to the addition of carbon black.
It has the property of absorbing laser light of 1.06 μm or less.

Further, a probe 56 formed in a cylindrical shape from polypropylene resin is provided at the tip of the irradiation nozzle 55 of the YAG: neodymium ³⁺ laser, and its diameter is equal to that of the plate member 52 made of polypropylene resin.
The diameter of the through hole 53 is smaller than that of the through hole 53 formed in the through hole 53, and the outer periphery of the through hole 53 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.

When joining the plate members 51 and 52 set as shown in FIG.
6 is moved to position its tip above the surface of the plate member 51. Next, the wavelength is 1.06 μm and the output is from the irradiation nozzle 55 of the YAG: neodymium ³⁺ laser.
Irradiate with 20WYAG laser light. This results in
The YAG laser beam passes through the cylindrical probe 56 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 beam that reaches the plate member 51 is accumulated as energy at that location, and the surface of the plate member 51 is quickly heated and melted by the energy. Then, the plate member 51
After sufficiently melting, the irradiation of the YAG laser beam is stopped, and the probe 56 is inserted through the through hole 53 as shown in FIG. 5, and its tip is pressed against the melted area. At that time, the melt 5 of the plate member 51
As the probe 1a is inserted into the probe 56, it bulges upward from the gap between the through hole 53 and the probe 56, and the thin wall portion 54 of the through hole 53 is covered with the melt 51a.

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

[Problems to be Solved by the Invention] However, in such a joining 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. However, since the laser beam is irradiated through a probe 56 with an aluminum vapor deposited layer 57 formed on its outer periphery, it is difficult to keep the irradiation diameter of the laser beam constant, and the plate member 51 that is about to be melted is heated.・In addition to uneven melting, both plate members 5
Since the shape of the eyelet 1 and 52 is also a cylindrical probe 56, the molten material 51a rises unevenly, and there is a problem that it is not possible to form the eyelet shape for strong joining.

Therefore, this invention was made to solve the above-mentioned problems, and 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, and the laser beam is formed into an eyelet shape. The purpose of this method is to uniformly heat and melt the synthetic resin material and prevent the molten material from bulging unevenly by making the tip of the probe a stepped conical shape.

[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. A cylindrical member is connected. In addition, a plurality of optical lenses are arranged with gaps inside the cylindrical body, and the laser beam incident from the optical fiber is made to emit parallel rays of arbitrary diameter to the cylindrical member. 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 eyelet portion of the molten synthetic resin material bulges evenly, and both synthetic resin materials can be firmly joined.

As the synthetic resin material used at the time of bonding, synthetic resin materials that do not absorb laser light include polyethylene, vinyl chloride, polypropylene, styrene-acrylonitrile copolymer, phenol, polyacetal, etc.
Synthetic resin materials that absorb laser light include polypropylene resin with added auxiliary materials such as carbon black, reinforced with glass fiber,
Also, styrene-acrylonitrile copolymer to which carbon black is added can be used. 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, the lasers used when joining synthetic resin materials include glass: neodymium ³⁺ laser,
Examples include YAG: neodymium ³⁺ laser, ruby laser, helium neon laser, krypton laser, argon laser, H ₂ laser, N ₂ laser, etc. Among these, YAG: neodymium ³⁺ laser is particularly 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 bond resin materials.

In addition, the laser output is 5W or more.
A range of 100W is suitable; if the output is less than 5W, it will not be possible to melt the synthetic resin material, and if the output is more than 100W, the synthetic resin material will evaporate or change in quality, resulting in poor bonding. It is possible.

[Effect]

In such a laser beam irradiation device for joining synthetic resin materials, when overlapping synthetic resin materials and joining them, at least the synthetic resin material disposed at the bottom of the overlapping synthetic resin materials is exposed to the laser beam. On the other hand, the upper synthetic resin material is made to be absorbent, and holes are formed in the upper synthetic resin material, 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. Then, a laser beam with a wavelength of 1.06 μm or less and an output of 5 W to 100 W is introduced from the optical fiber, and is irradiated from the tip of the probe to the synthetic resin material underneath.

At that time, the laser beam travels through multiple optical lenses disposed inside the cylindrical body while repeating convergence and expansion, and the final optical lens converts the laser beam into a parallel beam. passes through and reaches the synthetic resin material at the bottom, and heats and heats that area.
Melt.

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, 1 is a cylindrical body formed from a metal material,
This cylindrical body 1 includes an upper case 1a and a lower case 1.
The upper case 1a is screwed onto the lower case 1b, and both cases 1a and 1b have the same inner diameter. In addition, this cylindrical body 1
An optical fiber 2 connected to a laser oscillator (not shown) is connected to the upper end of the upper case 1a, and the laser beam M transmitted from the laser oscillator is transmitted to the core material of the optical fiber 2. The light is reflected within the cylindrical body 1 and enters the cylindrical body 1.

Furthermore, three optical lenses 4a, 4b, and 4c are arranged at intervals inside the cylindrical body 1. That is, the first optical lens 4a is a convex lens and 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. ing. Further, the third optical lens 4c is a convex lens like the first optical lens 4a, and is disposed near the lower end of the lower case 1b.

Then, the laser beam M incident from the optical fiber 2
becomes a laser beam Ma having a spread angle θ from the incident part 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 is incident on the optical lens 4c. Further, the spherical laser beam Mc that has entered the third optical lens 4c is emitted again as a parallel laser beam Md. and,
By combining the second optical lens 4b and the third optical lens 4c, the diameter of the emitted laser beam Mc can be arbitrarily changed.

In addition, a lower case 1 constituting the cylindrical main body 1
A cylindrical member 5 made of a metal material is provided at b. This cylindrical member 5 has a flange 5a formed at its upper end, and the flange 5a abuts against the lower end of the lower case 1b, and is held by a screwing fixture 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 7
From b, it is formed into a conical shape 7c, and its lower surface 7d is flat, and its upper surface 7e
It is also formed flat. Furthermore, the stepped portion 7a of the probe 7 is formed by a tapered process formed on the upper synthetic resin material Wa of the two overlapping synthetic resin materials Wa and Wb as shown in FIGS. 1 and 2. The conical portion 7c is sized to engage with the tapered surface Wd of the hole Wc, and the conical portion 7c has a smaller diameter than the machined hole Wc, 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 transmitted to the cylindrical member 5.
The light is guided by the light beam and reaches the probe 7, and in that state, the light passes through the probe 7 and irradiates the synthetic resin material underneath.

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, the synthetic resin materials Wa, Wb to be joined
Among them, the synthetic resin material Wb disposed in the lower part is made of styrene-acrylonitrile copolymer added with carbon black that absorbs laser light and reinforced with glass fiber, and the synthetic resin material disposed in the upper part The material Wa was made of polypropylene resin, and a tapered hole Wc was formed in the center thereof. After that, both synthetic resin materials Wa and Wb were added to the first
Overlap as shown.

Next, move the laser beam irradiation device above the processed hole Wc formed in the upper synthetic resin material Wa,
The tip of the probe 7 is inserted through the processed hole Wc and brought into contact with the surface of the lower synthetic resin material. Continuing,
The wavelength is 1.06μm from optical fiber 2 of W, and the output is
20W YAG: Laser light M made of neodymium ³⁺
is made to enter the cylindrical body 1, and the lower synthetic resin material Wb is irradiated from the tip of the probe 7.

At that time, the laser beam M incident from the optical fiber 2
enters the first optical lens 4a from the incident part of the upper case 1a as a laser beam Ma having a spread angle θ. The laser beam Ma incident on the first optical lens 4a is a parallel laser beam.
The laser beam Mb enters the second optical lens 4b, and the spherical laser beam Mc converges on a certain focal point again enters the third optical lens 4c. Moreover, the spherical laser beam incident on the third optical lens 4c
Mc is again emitted as parallel laser beam Md,
The lower synthetic resin material Wb is irradiated from the tip of the probe 7.

The laser light that reaches the lower synthetic resin material Wb is accumulated as thermal energy at that part, and the thermal energy is used to make the synthetic resin material Wb.
Wb is quickly heated and melted. 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 at the bottom rises upward from the gap in the processed hole Wc, and the stepped portion 7a of the probe 7 is inserted into the pressurizing hole.
It comes into contact with the upper surface tapered portion Wd of Wc, and is pressed upward by the lower surface 7b, so that a part of the molten material We covers the tapered portion Wd of the processed hole Wc formed in the upper synthetic resin material Wa.

After the tapered portion Wd of the processed hole Wc is sufficiently covered with the melt We, the irradiation of the laser beam M is stopped, the probe 7 is pulled up, and its tip is moved 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, it is extremely difficult to bond with other substances, and can be easily pulled up without adhesion of the molten material We.

As a result, the melt of the synthetic resin material Wb at the bottom
We hardens while covering the tapered portion Wd of the machined hole Wc formed in the upper synthetic resin material Wa, and both synthetic resin materials Wa and Wb are firmly joined. In addition, a recess formed by inserting the probe 7
Wf can be used as a pilot hole for a screw when the bond between the two synthetic resin materials Wa and Wb breaks.

〔Effect of the invention〕

As explained above, in the laser beam irradiation device for bonding 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 with a stepped conical tip,
This has the effect of preventing uneven build-up of the molten synthetic resin material and increasing the bonding strength.

Furthermore, in the laser beam irradiation device of the present invention,
Unlike conventional bonding methods, the molten synthetic resin material does not swell up or bulge on top of the synthetic resin material above, so there is an effect that the appearance after bonding can be improved.

[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 the 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... Cylindrical main body, 1a... Upper case, 1b...
... lower case, 2 ... optical fiber, 3 ... core material,
4a...First optical lens, 4b...Second optical lens, 4c...Third optical lens, 5...Cylindrical member, 5a...Flange, 6...Fixing metal fitting, 7...
...Probe, 7a...Stepped part, 7b...Bottom surface,
7c...conical shape, 7d...bottom surface, 7e...top surface,
M... Laser light, Wa... Upper synthetic resin material,
Wb...lower synthetic resin material, Wc...machined hole,
Wd...Tapered part, We...Melted material, Wf...Concave part.

Claims (1)

[Claims] 1. An optical fiber for inputting a laser beam is connected to one end of a cylindrical body, a cylindrical member for guiding the incident laser beam is connected to the other end, and a plurality of optical lenses are installed at intervals inside the cylindrical body. have and arrange;
A laser beam irradiation device for joining synthetic resin materials, characterized in that a probe made of a material through which laser light passes is provided at the tip of the cylindrical member, and the tip of the probe is formed into a stepped conical shape.