Laser welding of plastic components in automotive fuel systems

The introduction of the National Sixth Standard in the automotive industry has spawned a large number of injection-molded parts of the fuel system that need to be welded by lasers, such as the most typical welding of oil and gas separators, welding of various fuel lines and plastic joints, and mufflers. Welding, welding of various combined valve bodies, and welding of valve bodies such as check valves.

To sum up, the plastic laser welding parts of the above various fuel systems mainly use two materials: nylon with glass fiber and POM material. These two types of plastic materials are materials that have been proven for a long time in various laser plastic welding applications in the automotive industry, and there is no problem in themselves as laser welding materials. The main key points are as follows:

1. The plastic parts of the laser penetration layer should not be too thick in the weld area, the nylon material should be less than 2mm, and the POM material should be less than 3mm. Too thick wall thickness will increase the process difficulty and significantly affect the welding speed during the laser plastic welding process.

2. If the laser penetrating layer is made of a black laser penetrable plastic material, it must be noted that the laser penetration rate of the plastic material complies with the standard, and that ordinary black plastic materials will not be doped during the injection molding process. Be sure to wash the screw with the same plastic material before.

Laser welding of fuel system plastic components mainly uses three different plastic laser welding processes, rotary contour welding, plane contour welding and quasi-simultaneous welding.

Rotary profile welding

Rotary profile welding is used to weld fuel pipe fittings and pipe fittings. In rotary profile welding of plastic laser welding, the laser head focuses the laser to form a spot, and the pipe fittings are rotated for welding.

In practical applications, we found that there are some customers who use low-end plastic laser welding equipment. In order to obtain a wider weld seam, during the process of plastic laser welding, the movement axis is synchronized to achieve a wider weld seam. This method if Low-end lasers are used, and welding defects are extremely prone to occur in mass production.

There are many different variants of plastic laser welding methods for rotary contour welding, which are mainly divided into laser welding of fuel pipe fittings with rotation and laser welding of fuel pipe fittings without moving.

Flat profile welding

Flat profile welding is used to weld flat seams and is a standard process for plastic laser welding. During the welding process, the laser head focuses the light spot, and at the same time, the laser head is hung on the moving platform or robot and moves sequentially along the welding seam to complete the welding.

In practical applications, contour welding has higher quality requirements for injection-molded workpieces, especially for applications with complex welding lines such as oil and gas separators. Contour welding can achieve a certain penetration of the welding line in the process of plastic laser welding, but this penetration is small and uncontrollable, which requires that the deformation of the injection molded parts cannot be too large.

Quasi-simultaneous welding

Quasi-synchronous welding is one of the most widely used laser plastic welding processes in the automotive industry. During the quasi-synchronous welding process, the welding ribs can have a relatively large penetration depth, so it can compensate for a certain deformation of the injection molded parts. lower.

For the plastic laser welding application of the fuel system, no matter which of the above welding methods is used, it is necessary to pay great attention to the welding rib design of the welding product. Designing welding ribs and products that meet the technical requirements of laser plastic welding can make the future process development process much simpler. .