Plastic laser welding

Principle of Laser Welding

Plastic Laser Welding is to combine two plastic parts to be welded with external pressure, and then direct a beam of short-wave infrared laser to the area to be welded to achieve plastic laser welding. The laser beam passes through the upper light-transmitting material, and then the lower material absorbs the short-wave infrared laser. After the laser absorbs, the light energy is converted into heat energy. Since the upper and lower layers of materials are bonded together by external pressure, the two layers of materials melt and combine together. At the same time, due to the internal stress generated by the thermal expansion and expansion of the material itself, the internal stress and external pressure work together to ensure that the bonding surfaces of the two materials are fully bonded, melted and solidified, thereby realizing the plastic laser welding process. For products that do not absorb short-wave infrared, our company provides long-wave 2-micron plastic laser welding or coating laser additives to achieve the plastic laser welding process.

Welding method

1. Contour welding: The laser welding head moves along the welding rib of the light-absorbing layer (translucent layer) to melt it, so that the light-transmitting layer and the light-absorbing layer gradually melt; or for products such as round sleeves, the laser moves along the sandwich along the fixed laser beam to achieve the purpose of welding.

2. Quasi-synchronous welding: The laser welding head does not move, and welding is achieved by quickly moving a laser beam along the weld rib. The welding trajectory is processed by the PC end to process the vector file, and the laser beam moves along the graphic trajectory shown in the vector file, that is, the weld rib of the product at high speed to achieve welding.

3. Mask welding: This welding method is mostly used for medical products, especially products with microchannel structures such as microfluidic control. This welding method is similar to the quasi-synchronous welding method. The biggest difference lies in the mask. The mask can be likened to a sunshade with a watermark, and light cannot penetrate the watermark. The mask is coated with a laser-reflecting material, and the laser reflection cannot penetrate the parts of the product that do not need to be welded. The parts without reflective material are welded with laser.

4. Synchronous welding: Synchronous welding is similar to ultrasonic welding, but synchronous laser welding has no amplitude and is a non-contact processing in which the welding head does not directly contact the product. Synchronous welding uses multiple laser welding heads to emit lasers at the same time. After a certain shaping, the laser is guided along the contour line of the welding layer, and heat is generated at the welding point, so that the entire contour line is melted and bonded at the same time.

Advantages of Plastic Laser Welding

1. Non-contact and flexibility.

2. Minimization of thermal stress on welded parts.

3. Simple welding shape.

4. Vibration-free processing.

5. Ideal weld.

6. High precision and strength.

7. Good air tightness and water tightness;

8. Compared with ultrasonic and vibration welding, it has low mechanical stress, no surface damage, no welding slag, and low tooling cost.

9. Compared with hot plate and hot air welding, it has low thermal stress, no welding slag, less stabs, short production cycle, and low equipment and tooling cost.

Plastic Laser WeldingApplication:

Plastic laser welding technology is a very professional bonding technology. When high-speed welding and precision welding or aseptic welding are required, the best advantages of laser welding are exerted. This technology was once restricted by price factors, but with the continuous decline in equipment prices, it is more competitive than ultrasonic welding and hot plate welding in many application fields. The main application areas of laser welding technology include medical, automotive, electronics and packaging.