At present, many products (including the automotive semiconductor industry, the pharmaceutical and food industry, etc.) have very high requirements for processing accuracy and aesthetic appearance, which makes laser welding a necessary process for the production of these products and promotes the further development of laser welding technology.
The closer the compatibility, fusion temperature, and matching of plastic laser welding are, the better the effect will be. The application methods of plastic laser welding are different from those of metal welding, including sequential circumferential welding, quasi-synchronous welding, synchronous welding and irradiation mask welding.
1.Contour welding
The laser moves along the contour of the plastic welding layer and melts it, gradually bonding the plastic layers together; or the sandwiched layer is moved along the fixed laser beam to achieve the purpose of welding.
In practical applications, contour welding has higher quality requirements for injection molded workpieces, especially applications with complex welding lines such as oil and gas separators. Contour welding can achieve a certain penetration depth of the welding line during the plastic laser welding process, but this penetration is very small and uncontrollable, which requires that the deformation of the injection molded parts should not be too large.
2. Simultaneous welding
The laser beam from multiple diode lasers is shaped by optical elements. The laser beam is guided along the contour of the welding layer, while generating heat at the weld, so that the entire contour melts and bonds at the same time. Together.
Simultaneous welding is mainly used in automotive lighting and medical industries. Simultaneous welding is a multi-beam, optically shaped light spot that presents the welding trajectory. Its characteristic is to reduce internal stress. Because the requirements are relatively high and the overall price is relatively high, it is widely used in medical treatment.
3. Scan welding
Scanning welding is also called quasi-synchronous welding. Scanning welding technology combines the above two welding technologies of sequential circumferential welding and synchronous welding. A reflector is used to generate a high-speed laser beam with a speed of 10 meters/second and moves along the part to be welded, causing the entire welding part to gradually heat up and fuse together.
Quasi-synchronous welding is the most widely used. In the automobile and auto parts industry, it uses an XY high-frequency galvanometer inside. Its core is to control the collapse of plastic welding between two materials. Contour welding will produce large internal stress, which will affect the sealing of the object. Quasi-synchronous is a high-speed scanning method, and it cooperates with current control, so it can effectively eliminate internal stress.
4. Rolling welding
Roll welding is an innovative laser plastic welding process that comes in many different forms. There are two main forms of roll welding:
The first is Globo ball welding. There is an air-cushion glass ball at the end of the laser lens. This glass ball also plays the role of focusing the laser and clamping the plastic parts. During the welding process, the Globo lens is driven by the motion platform and rolls along the welding line to complete the welding. The whole process is as simple as writing with a ballpoint pen. The Globo welding process does not require complicated upper fixtures, and only requires the production of a bottom mold to support the product. There is also a variant of the Globo ball welding process, the Roller roller welding process. The difference is that the glass ball at the end of the lens is changed into a cylindrical glass barrel to obtain a wider laser line segment. Roller roller welding is suitable for wider welding.
The second is the TwinWeld welding process. This plastic laser welding process adds a metal pressure wheel to the end of the lens. During the welding process, the pressure wheel presses the edge of the welding line for welding. The advantage of this plastic laser welding process is that the metal pressure wheel will not wear out, which is conducive to large-scale production. However, the pressure of the pressure wheel acts on the edge of the welding line, which easily generates torque and causes various welding defects. At the same time, because the lens structure is relatively complex, it causes certain difficulties in welding programming.
5.Irradiation mask welding
The laser beam is positioned through the template to melt and bond the plastic. The template only exposes a small and precise welding area on the plastic layer below. The laser beam only heats the part of the product that is not covered by the mask. High-precision welding down to 10 microns can be achieved using this technology.
Microfluidic components can be welded precisely and securely using the mask welding principle. The channel geometry remains intact, preventing melt from flowing into narrow channels of only 200 µm.
Applications of Laser Welding in the New Energy Automobile Industry
Common Queries about CO2 Laser Marking Machines:You Need to Know
