A Chart Reveals Which Plastics Can Be Welded with Laser — Wanzhong Laser

Plastics are a highly versatile material with diverse applications. Welding methods for plastics include hot pressing, ultrasonic welding, and laser welding. Today, Wanzhong Laser shares key material requirements for plastic laser welding processes.
Plastic laser welding operates by applying external pressure to assemble two plastic components, then directing a short-wavelength infrared laser beam onto the joint. The laser penetrates the upper transparent layer, while the lower layer absorbs the infrared radiation, converting light energy into heat. This thermal energy causes the materials to melt and fuse together under external pressure. Simultaneously, thermal expansion generates internal stresses that work in tandem with the external pressure, ensuring complete adhesion, melting, and solidification of the bonding surface. This coordinated process ultimately achieves the laser welding technique.
Those familiar with plastic welding know that different plastics exhibit distinct properties—melting points, light transmittance, and light absorption—all of which affect welding outcomes. Broadly speaking, laser welding is applicable to thermoplastic and modified engineering plastics such as ABS, AS, PP, PE, PA, PC, PVC, PMMA, PS, and PET. The specific applications are illustrated in the following diagram:
In the diagram, the green section indicates plastics that are highly suitable for laser welding, yielding excellent results. The blue section represents plastics confirmed to be weldable by laser, with satisfactory outcomes. The red section denotes plastics that can be laser welded but require further testing for confirmation. Other cases demand experimental verification. All data are derived from extensive sample testing.
While the materials mentioned above are weldable, many plastic products undergo modification processes with the addition of auxiliary materials, which may render them unsuitable for laser welding. Furthermore, the color and light transmittance of plastics are critical factors affecting laser welding performance. For instance, two black, opaque plastic parts cannot be joined using this technique.
In summary, to confirm whether plastic parts can be laser welded, you may consult the plastic laser welding machine manufacturer—Wanzhong Laser. They offer free sample production, personalized customization, and plastic product laser welding contract manufacturing services.