How waterproof are laser welded plastics?

In laser transmission welding, the parts are pressed in a clamping device and joined in the welding geometry. The advantages of this welding technology are the contactless energy input and low stresses on the mechanical and thermal components. The weld seams are very uniform and clearly visible. In some applications, they are even used as design elements. The most common processes are contour welding and quasi-envelope welding. It also allows process monitoring to ensure quality. What about the waterproofness of laser welded plastics?

Welding Plastic Enclosures for Electronics

Many applications require printed circuit board (PCB) enclosures that protect sensitive electronics from the environment.

Silicone encapsulation is a common method that is increasingly being replaced by laser welding. Compared to other welding methods, laser welding has the advantage of introducing non-contact energy, which can minimize thermal and mechanical stress on the parts. Eliminating packaging materials also increases the convenience of environmental handling because there is no need to separate materials.

Housing Welding

Plastic housings, casings and more are increasingly being joined by lasers. A good example is the taillights of cars.

A good example is the taillights of cars. Laser welding is replacing conventional methods such as hot plate welding or friction welding. In addition to the optical appearance of the weld, it also increases the reliability of the weld. Other examples of the use of laser welding in everyday life are lighting components for roads and buildings, soaps or multimedia components such as smartphones and headphones.

Welding of plastic housings for waterproof protection

Housing welding is used in many different situations. One of the applications is the protection of people in open water. The bracelet, as part of the watch design, is equipped with sensitive sensors. Once the preset parameters such as time, water depth, etc. are exceeded, a red balloon is triggered and an audible warning signal is emitted.

This way, rescue will be faster because you can find the person who fell into the water faster. In this application, laser welding needs to be divided into several challenges. First, it requires a waterproof seal of the housing parts to protect the electronics. Secondly, it needs to use the color specified by the customer. The first challenge was successfully achieved by quasi-simultaneous welding. The second challenge involves some chemical reactions. The color of the cover and the housing needs to look the same in the wavelength range of visible light. However, the cover needs to be laser-resistant while the housing needs to absorb the laser. This can be achieved by using appropriate additives in the plastic. As a result, the safety wristband is not only functional but also visually appealing.

In addition to the plastic housing welding and sealing welding process, plastic laser welding machines are also widely used in the laser welding industry.