As a kind of high molecular weight polymers material, plastic has been widely used in various industrial fields. Plastics are mainly composed of resin and can be divided into thermoplastic and thermosetting plastics according to the molding method.
Thermoplastics become soft after heating, solidify and shape after cooling, and the process is repeatable. Common materials include,
General plastics, such as polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), acrylonitrile-butadiene-styrene (ABS), polymethyl Methyl acrylate (PMMA);
Engineering plastics, such as nylon (Nylon), polycarbonate (PC), polyurethane (PU), polytetrafluoroethylene (Teflon, PTFE), polyethylene terephthalate (PET), etc.;
Special plastics, such as "artificial heart valves," "artificial joints," and "medical polymers."
The thermosetting plastic becomes soft after initial heating, and after reaching a specific temperature, it becomes solidified and formed with a chemical change. This process is irreversible and irreproducible. Common materials include phenolic resin (PF), epoxy resin (EP), amino resin, unsaturated polyester resin (UP) and so on.
After the plastic is molded, it will undergo secondary processing, and the most important thing is to connect the plastic according to various needs. Generally, plastic connection methods include glue bonding, ultrasonic welding, friction welding, thermal welding, and laser plastic welding. Among them, laser plastic welding has been used in more and more applications.
Most of the current laser plastic welding is for colored plastics, or it is necessary to add additives for auxiliary welding. These plastics are widely used in industries such as automotive electronics or mobile phones.
For some special fields, like biomedical fields and LED lightboxes, which require no additives applied. The common materials include polymethylmethacrylate (PMMA), polycarbonate ( PC), acrylonitrile-butadiene-styrene (ABS), cyclic olefin copolymer (COC) and others. These transparent plastics are difficult to use ordinary laser welding because of the low absorption rate for visible light or near-infrared light. Han's Laser has 2 microns wavelength laser plastic welding solution to accommodate this kind of demand.
What is laser plastic welding?
Laser welding plastic, the laser beam, after transmission through the upper-layer transparent material, will be absorbed by the lower layer. The laser energy, after being absorbed, will be transformed into heat. Since two layers of materials are forced together, the heat will be conducted to transparent layer from absorbing layer, which would make the two layers of materials melt and connected. At the same time, the internal pressure occurs because of the material’s thermal expansion. The total effort of the internal and external pressure can make sure two layers are firmly welded. For the product lower-layer material does not absorb laser, additive needs to be applied to the lower layer.
Almost all thermoplastics and thermoplastic elastomers can use laser welding technology. Commonly used welding materials are PP, PS, PC, ABS, polyamide, PMMA, POM, PET and PBT. However, some other engineering plastics, such as polyphenylene sulfide PPS and liquid crystal polymer, are not suitable for laser welding technology because of their low laser transmittance. Therefore, addictive is often added to the underlying material so that it can absorb enough energy to meet the requirements of laser transmission welding.
Widely applied to the reinforcement and sealing welding of plastics Medical plastic parts.