Laser welding of plastics has several advantages over other joining methods, but its proper implementation requires knowledge of the technology and discussion with the equipment supplier early in the product development cycle.
Plastics have several unique properties and advantages over other materials. These include high strength-to-weight ratio, mechanical flexibility, corrosion resistance, electrical and thermal insulation, as well as low unit cost. All this has led to the increased use of plastics in areas as diverse as packaging, automotive manufacturing, microelectronics and medical devices. A common requirement in many of these applications is the joining of two or more plastic parts to assemble a product. For applications involving sophisticated products, this joining must be done with high mechanical precision and excellent strength and cleanliness of the joint.
In high-volume production, some form of welding is usually used instead of bonding. This is because welding can usually be done much more quickly and accurately than gluing, while producing a stronger and more reliable connection. In addition, laser welding offers a combination of other benefits.
| Precision | The highly localized application of energy causes little or no change in part size, allows small dimensional tolerances and can be used on complex shaped parts. |
| Repeatability | The laser process is inherently highly consistent and can be precisely controlled by process monitoring equipment. |
| Weld quality | Laser welding of plastics does not affect the surface of the parts being welded and can produce invisible welds. The welded joints do not need to be machined afterwards. |
| Weld strength | Laser welding provides a strong weld that can be hermetically or pressure tight. |
| Low contamination | Laser welding does not use additive materials and does not create any impurities or material contamination. At the same time, virtually no impurities or fumes are produced. |
| Speed | The laser welding process is fast and well automated. |
The easiest way to integrate plastic welding
The Coherent ExactWeld IP laser is the easiest way to integrate plastic welding into a production line. Why is ExactWeld IP so easy to integrate? Primarily because it includes everything you need for the entire welding process - a high power diode laser source, a galvanometric laser beam distribution system, precision part clamping mechanics and all associated control electronics and software interfaces. All you have to worry about is integrating Coherent ExactWeld IP technology into your production. And that's easy, because it's also available with adapters for conveyor belt, turntable or robotic arm part loading.
The power is on your side
Once up and running, the ExactWeld IP produces perfect welds. This is thanks to a clamping system that offers a huge range of clamping forces (100 N - 4500 N), as well as automatic part collapse height measurement and closed-loop clamping control. This means consistent, high-quality welds, even when part-to-part or other process variations occur.
In addition, many other options are available to help ensure weld quality. These include thermal imaging inspection for automatic detection of welding defects, an integrated vision system for part detection or offset correction, and an automatic laser power calibration module to increase stability and consistency throughout the process.
The ExactWeld IP system will not slow down your line even when production changes. You can change the fixtures for processing different parts simply by placing the new fixture directly into the parts bin - for example, on a conveyor belt. The ExactWeld IP system picks it up, installs it, reads the RFID tag on the fixture, and then immediately and automatically adjusts the process pattern, mechanical shifts, or other product-specific configurations.
How do you handle larger production lines?
If your production requires a truly complex production line, Coherent Compact diode lasers are the solution. This is a comprehensive range of air- or water-cooled lasers with power ratings from 50 to 1200 W designed for integration into production lines. The lasers can be complemented by a fixed or scanning process head, an optional extra can be an integrated pyrometer with a powerful control unit to control the temperature of the welding process in a closed loop, or camera systems for part detection and weld quality control.
Unrivalled support
But introducing laser welding into your production requires more than just quality hardware. It usually involves process development, optimization of process recipes and the design of custom fixtures to ensure controlled and homogeneous pressure throughout the welding area. Coherent is your partner in all of these areas. Our application laboratories and skilled personnel will guide you from feasibility analysis, through process and tool development to equipment installation and operator training. We are with you every step of the way.