eBind in the newly developed colorant for Laser Transmission Welding (LTW). A laser beam transmits through the transmission layer and changes into heat at the interface of the transmission and absorbent layer. The heat of the beam works to weld the two layers into one part.
Which application is used for Resins? "Resins" or "plastic materials" are used in all elements of our lives. For example, a lot of applications for resin (plastic products) are still available for a large variety of industries.
Resins and Main Applications of Industry
Main Application (Plastic Products)
Bumper, spoiler, over-fender, roof-rail, wheel cover, lens cover, instrument panel, console box, brake pedal, door trim, air duct
CD, lighting equipment, lighter, game machine, bulk container, pallet, eyeglass, camera, watch, musical instruments, helmet, fastener, power tool, airplane interior, agricultural film.
Engine cover, bumper, spoiler, ash tray
Electrical & Electronics
IC board, distribution board, socket, switch, connector, bobbin
Adhesive, paint, gripper of pan and kettle, dish, decorative sheet, bath tub.
What are "Thermo Plastics" and "Thermoset Plastics"?
Generally, the "Resins" are classified as the "Thermo Plastics" and "Thermoset Plastics".
Thermo Plastics: The resins are soft after heating.
Thermoset Plastics: The resins are rigid after heating.
In a word, "Thermo Plastics" are like a "chocolate". They can be melted at the moment of heating again and again.
Conversely, "Thermoset Plastics" are like a "biscuit". They can be melted at the moment of heating once and for all. However, after then, they cannot be melted even if the heating is repeated.
Top What is LTW (Laser Transmission Welding)? As a new welding method (except for hot plate, vibration and ultrasonic welding) LTW has recently come under the spotlight.
LTW is one of the methods of thermal welding and makes use of the heat melted resin instead of an adhesive.
However, the heat source of LTW is different from that of thermal conventional welding. The heat source of hot plate welding makes use of the heated hot plate. Vibration and ultrasonic welding makes use of the frictional heat. In the case of LTW, the heat source is obtained by absorbing heat from the laser beam on the surface of the resin.
When you were a child, you would bring the sunshine into focus with magnifying lens on the black paper and burned the paper. As for LTW, the sunshine is replaced with the laser beam, the black paper is replaced with black resin, and the light energy is converted into the thermal energy. In other words, LTW is utilized for the photo-thermal transfer of the laser beam.
You will be able to understand that the light energy of laser beam is converted into the thermal energy on the surface of the black resin and the black resin is melted. Then, how is the black resin joined?
First, when the laser light radiates the two pieces of the resin on the condition of the suitable pressure, the laser light is transmitted to the "Laser Transmission Material" and is heated (melted) on the surface of the "Laser Absorption Material". Next, the heat is melted to the "Laser Transmission Material" by means of the thermal conductivity and the melting pool is formed between the "Laser Transmission Material" and the "Laser Absorption Material". Finally, they are joined.
Laser Beam It is necessary to radiate the laser beam of LTW. There are YAG laser [wave length: 1064nm] and LD (Laser Diode) [wave length: 808nm, 840nm & 940nm] in the type of resin laser beam. It is generally the most effective to use LD with the welding of resin because of the economical efficiency and quality of the laser beam.
What are the features of LTW? As you know, LTW is different from such welding method such as hot plate, vibration and ultrasonic welding. There are a large variety of features of thermal welding that have never been seen. For example, LTW has the advantage of good surface finish and no flash.
Also, the thin wall of the plastic parts can be welded because the radius of the beam can be optically controlled and there is little heat stress in the parts.
LASER TRANSMISSION WELDING (LTW)
First, the "Laser Transmission Material" (which can transmit the laser beam) is overlapped on the "Laser Absorption Material" (which can absorb the laser beam).
Next, the laser light radiates the two pieces of material on the condition of the suitable pressure. Then, the laser light is transmitted thru the "Laser Transmission Material" and is heated (melted) on the surface of the "Laser Absorption Material".
The heat is melted to the "Laser Transmission Material" by means of the thermal conductivity and the melting pool is formed between the "Laser Transmission Material" and the "Laser Absorption Material".
Finally, the "Laser Transmission Material" and the "Laser Absorption Material" are joined.
Good surface appearance (non-contact welding)
Localized heating (The thin wall of the plastic parts can be welded because the radius of the beam can be optically controlled and there is little heat stress in the parts.)
Reliability (Welding strength, Hermetic property, and precise energy control).
No vibration (E.g.: No adverse impact on the precision junction parts).
Quietness (E.g.: No noise generated by comparison of the ultrasonic sound).
Workability (No flash and no dust)
Productivity (Welding speed)
Two types of materials (transmission/absorption) are needed.
Electric Key, Head Lamp, Tank, Plug, Injector, The other precision junction parts.