Laser in Automotive Plastic Parts

In the face of the world's largest plastics demand market, plastic laser welding technology has broad market prospects. Plastic laser welding technology is widely used in medical equipment, electronic components, automotive parts, textiles, and packaging industries. For example, in modern vehicles, whether it is exterior trim (such as bumpers, fenders, wheel covers, deflectors, etc.), interior trims (such as dashboards, door panels, sub-dashboards, glove compartment lids) , seats, rear guards, etc.), or functional and structural parts (fuel tank, radiator water chamber, air filter cover, fan blades, etc.), the shadow of plastic parts can be seen everywhere.

Plastic laser welding technology belongs to non-contact welding technology. Compared with other welding methods, it has many advantages, such as non-contact, air-tight, water-tight, fast welding speed, high precision, high weld strength, no flying edge, no residue, no vibration, minimum thermal stress, easy control, good flexibility and good adaptability. The connection of automotive plastics is the key link of its wide application. The level of plastic welding technology is one of the symbols to measure the level of automotive production technology and development of new materials. Nowadays, laser welding is more economical, simple, fast, reliable and suitable for mass production. It has been more and more widely used in the automotive industry.

Automotive plastics are divided into thermosetting plastics and thermoplastics. Most of the natural plastics and many colored translucent plastics can be laser welded, such as PS, PVC and PP. For thermoplastics with low absorption rate, one selects the type of laser; the other is that by adding a laser sensitizer (such as carbon black), the absorption rate of the near-infrared laser can be greatly improved. By studying the laser reflectivity and transmittance of various plastic materials, it is possible to solve the problems of materials such as laser-welded plastics. There are usually several different welding methods for plastic laser welding:

Laser moves along the outline of the plastic welding layer and melts it, gradually bonding the plastic layer together, or moving the interlayer along a fixed laser beam to achieve the purpose of welding. Laser beams from multiple diodes are guided along the outline of the welded layer and melt the plastic so that the entire outline melts and bonds together at the same time. This technology combines the above two welding technologies. A high-speed laser beam (at least 10m/s) is generated by a reflector, and it moves along the part to be welded, making the whole welding place gradually heated and fused together. Laser beams are positioned, melted and bonded to plastic through a template, which exposes only a small, precise welded part of the plastic layer below. Using this technology, high precision welding can be realized with less than 10 microns.

According to statistics, there are dozens of kinds of plastics used in automobiles. The average amount of plastics used in each automobile has accounted for 5%-10% of the automobile's self-weight. The plastic material of 100 kg on modern automobiles has replaced the traditional metal material of 200-300 kg. The effect of weight reduction is very prominent, which is of great significance for saving energy and reducing greenhouse gas emissions. For example, replacing metal with plastic intake manifold can reduce the mass by 40%-60%, and the surface smooth flow resistance is small, which can improve engine performance, and play a certain role in improving combustion efficiency, reducing fuel consumption, vibration and noise reduction.

The introduction of the national standard for the automotive industry has spawned a large number of injection molded parts for fuel systems that require the use of lasers for welding, such as the welding of the most typical oil and gas separators, the welding of various fuel lines and plastic joints, and silencers. Welding, welding of various combinations of valve bodies, welding of valve bodies such as check valves, and the like. Plastic laser welded parts for various fuel systems use two main materials: glass-coated nylon and POM materials. Both types of plastic materials have been proven for a long time by various laser plastic welding applications in the automotive industry, and there is no problem in the laser welding material itself.

The laser welding of the plastic parts of the EPB electronic parking system mainly involves laser welding of the EPB electronic parking controller housing and the plastic housing of the EPB electronic parking MGU component. In the structural design, the design of the EPB controller and the MGU component housing adopts the quasi-synchronous welding design structure. The bottom rib is designed with welding ribs. The laser spot is quickly scanned along the welding ribs, and the entire welding rib is melted to form a bed to complete the welding. The advantage of the quasi-synchronous laser plastic welding process is that it can compensate the deformation of the plastic parts by the downward collapse of the welding ribs on the one hand, and can be used as one of the standards for quality monitoring by monitoring the collapse of the welding ribs on the other hand.

Laser welding of plastic parts of EPB electronic parking system mainly involves laser welding of EPB electronic parking controller shell and EPB electronic parking MGU component plastic shell. On the structure design, EPB controller and MGU parts shell are designed by quasi-synchronous welding. Welding ribs are designed on the bottom shell. Laser spot is scanned along the welding ribs quickly, and the whole welding ribs are melted to form a bed to complete welding. The advantage of quasi-synchronous laser plastic welding technology is that on the one hand, the deformation of plastic parts can be compensated by the collapse of welding ribs; on the other hand, the collapse of welding ribs can be monitored as one of the quality control standards.

According to aerodynamics, automobile lamps with different shapes are designed. In the past, traditional plastic welding technology, including laser welding technology, can only weld two-dimensional components. Today, three-dimensional plastic laser welding technology can break through the obstacles of two-dimensional. It can seamlessly connect three-dimensional objects, not only improve the quality of products, but also greatly reduce production costs.