Laser processing technology has gradually penetrated into industrial manufacturing and become an emerging technology that has attracted much attention. At present, among all laser material processing applications, the manufacturing of metal parts is the main one, accounting for more than 85% of the share. The remaining 15% of applications are distributed in non-metallic materials such as wood and paper products, cloth and leather, fiber materials, plastics, glass, semiconductors, etc. metal products. Lasers in different spectral wavelength ranges exhibit different absorption and efficiency for different materials. In other words, for materials with certain properties, you can always find a type of laser with the highest absorption rate and the most suitable processing.

At present, the laser processing technology of metal materials has been fully explored, including cutting, welding, cladding and cleaning. The next hot growth point will be laser processing of non-metallic materials. In particular, glass, plastic, and wood and paper products are the most common types of materials in life and industry. Among them, plastic is the most representative because of its plasticity in various shapes. It has been transformed into a variety of industrial parts and daily necessities, and its application volume is very large. For a long time, the connection of plastics has remained a problem that is difficult to solve satisfactorily.

                  

Plastic joining process

Plastic has good thermoplasticity, so once the local area that needs to be connected is heated, it will soften and melt, making it easy to splice. However, the efficiency and splicing quality of different methods vary greatly. At present, there are several main ways to connect plastic parts: the first is the most traditional glue bonding. Current industrial glues often have odors and even produce toxic substances such as formaldehyde, which does not meet environmental protection requirements. The second is the connection of fasteners or fasteners, such as pre-made buckle positions on two pieces of plastic that are easy to disassemble, or using screws to connect two pieces of plastic together. The third type is splicing that uses heat to melt plastics. Types include induction welding, hot plate welding, hot gas welding, vibration friction welding, ultrasonic welding and laser welding.

The connection between fasteners and fasteners has certain necessary significance. It is generally used for two plastic parts without permanent dead connection. The heat-melted splicing is generally a permanent connection between plastics. The efficiency of hot plate welding is very low, the accuracy is not enough, and the degree of automation is low. At present, vibration friction welding and ultrasonic welding are mostly used, and the relevant equipment only costs tens of thousands of dollars. , and suitable for mass production. However, ultrasonic waves will produce noise, which limits the size of the welding workpiece. At the same time, it is easy to cause uneven heating of the interface and errors in the welding effect. Laser welding of plastics has gradually emerged and attracted the attention of the plastics industry.

Plastic laser welding

Plastic laser welding is a technology that uses the heat energy of laser to permanently connect thermoplastic parts. Before welding, it is necessary to add appropriate external force to clamp the area to be welded between the two parts, and adjust the wavelength of the near-infrared laser suitable for the material of the part. The laser first transmits through the first part, is absorbed by the second part and turns into Thermal energy melts the contact surfaces of the two parts to form a welding zone, completing the welding.

Plastic laser welding has the advantages of high efficiency, fully automated control, high precision, good weld sealing, firm welding, and less damage to plastic parts. At the same time, there is no noise or dust. It is a very ideal plastic welding process.

The current problems with plastic laser welding are that the equipment is slightly more expensive than traditional processes; the second is the difficulty in welding caused by laser absorption caused by the combination of plastics of different colors, especially when the upper and lower layers are transparent plastics, which is more difficult, but In the future, we can explore the use of coatings to assist laser absorption; thirdly, there is still insufficient research on various application scenarios, loading and unloading, fixtures, and automation of plastic laser welding.

Plastic laser welding applications

Theoretically speaking, plastic laser welding can be used in all industries related to plastic connections. Swiss Leister and German Rofin are pioneers in research and application. In recent years, there are also companies in my country engaged in plastic laser welding equipment. The most common applications are in automobiles, medical equipment, On plastic parts of home appliances, consumer electronics, etc.

In automobiles, plastic laser welding machines using quasi-synchronous welding are used in the welding of various combination valve bodies, valve bodies such as one-way valves, and automobile dashboards; plastic laser welding machines using sequential contour welding are used in various applications. Various fuel lines and plastic joints, as well as high-end car bumpers, car welcome light welding, eddy current fans, car rear tail lights, oil and gas separators, etc. Automotive 360 cameras, automotive radars, automatic door locks, electronic parking controllers, head-up displays, etc., all use plastic laser welding to achieve high product quality and economy.

In terms of medical devices, plastic laser welding is used in the sealing and welding of medical hose connections, blood analyzers, hearing aids, gastroscope connections, liquid filter tanks and other devices that require high cleanliness.

In the welding of consumer electronics, for example, plastic laser welding is used to weld watch straps and package VR glasses, which can achieve beautiful appearance and high weld strength. Plastic laser welding is also used in mobile phone parts (casings, headphone holders, USB holders) mice, sensors, etc. Some companies have now applied plastic laser welding to battery packaging welding.

More informaitons, please contact Laisai Laser.