Wide Application of Laser Welding in the Field of Medical Equipment
- Today, with the continuous innovation of laser technology, laser welding technology is also constantly being used in the field of medical device manufacturing.
Laser welding is mainly used for micro-welding of precision and complex parts.
Medical devices are usually hand-held tools or small components that are often used in surgery or implanted into the human body. The welds that connect these parts together are critical to patient health. Therefore, strict control of weld quality is required, which requires repeatable laser pulses, small spot diameters, and efficient absorption of laser energy through the material. Generally, the welding process with penetration depth and welding spot size less than 1mm is called laser micro welding. Laser microwelding is commonly used for precision welding of products such as pacemakers, surgical blades, endoscopic instruments, and batteries.
- There are various laser sources suitable for micro welding, including pulsed neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers, continuous wave (CW) fiber lasers, nanosecond fiber lasers, quasi-continuous wave (QCW) fiber lasers and High Brightness Direct Diode (HBDD) lasers. Which type of laser light source is most suitable is ultimately determined by process requirements, manufacturing requirements and materials.
Laser microwelding can be divided into two types: spot welding and seam welding. Spot welding is required for medical tubes, thin spring electrical contacts, hook assemblies, medical guide wires and medical hypowires. The spot welding process requires the precise delivery of laser energy to the welding spot, so a suitable laser spot is required.
The size of the laser spot depends on the type of laser and its beam quality, for example:
1) The spot size of the fiber laser (CW, QCW and nanosecond) is 20~200μm
2) The spot size of Nd:YAG and HBDD lasers is 200~1000μm
Seam welding is a method used to seal human implantable devices and can be achieved using pulsed Nd:YAG lasers or CW lasers. Which laser is used depends on the geometry of the weldment or the sensitivity of the material to heat.
- As the complexity of parts continues to increase, it has become a trend to weld different kinds of materials together. For example, copper and aluminum, or two different aluminum alloy materials, are welded together. In general, welding between dissimilar metals needs to be avoided because the resulting weld may produce brittle intermetallic compounds.
However, new research shows that by shortening the interaction time with the laser and minimizing the melt pool, dissimilar metals can be joined together. Like any other weld, although these dissimilar material welds also need to be tested for suitability and use, this dissimilar material welding method offers the possibility of joining new materials, which will further promote the development of medical devices. develop.