What Is a Laser Welding Machine?
A laser welding machine is a device that uses laser beams to weld two objects together. They are mainly used for bonding resins, utilizing the heat generated by their laser beam. Other welding methods include those using a heat plate and ultrasonic waves, all of which use the generated heat to melt the object and bond it when it cools. When the melted parts dissipate heat, they connect the boundary parts and cool and solidify. This is a clean device that can bond even the smallest of parts and does not generate any dust during the bonding process.
Applications of Laser Welding Machines
Laser welding machines are used for products that require a clean appearance and high-water resistance.
An example is car tail lamps. Tail lamps need to emit a beautiful light in an easy-to-see color. However, if plastic parts are joined together using screws or adhesives, the lamps will not look good. This is where laser welding machines can be used to create a beautiful finish without the use of adhesives.
Laser welding machines are also used for bonding products that require high waterproof performance, such as medical tanks. Since no screws or adhesives are used, the products are highly waterproof and less likely to deteriorate over time.
Principles of Laser Welding Machines
Laser welding machines bond objects together by melting the resin with a laser beam. First, a resin that transmits laser light and a resin that absorbs laser light are prepared. Next, the transmissive resin is placed on top and the absorbent resin is placed on the bottom, and the laser beam is applied from above. The light penetrates the transmissive resin and is continuously irradiated onto the surface of the absorptive resin, causing the interface between the two to generate heat. This heating causes the resin to melt, resulting in welding. Once melted, the resin cools and hardens when the laser is stopped, and the two resins are bonded together.
However, this method cannot be used for all types of resins, as both permeable and absorbent resins must be prepared. If both resins are permeable or absorbent, laser welding machines will be difficult to use. Basically, resins with high transmittance are white or transparent, and resins with high absorption are almost black.
The solution is to apply a laser absorbing agent to the underlying resin when the resins are white or transparent to each other. The absorbent will prevent the laser light from passing through the underlying resin, so the welding can be done in the same way as the normal method. In the case of black-on-black resin, the upper resin is welded using a permeable resin that is similar to black.