CO2 laser used in medical equipment welding

Probes and leads used in medical equipment must be made of different alloys, depending on the end use of the equipment. The solder joints must be smooth and free of pores so that the equipment can be repeatedly sterilized in the autoclave. In some cases, medical equipment is small and requires microscopic welding. OEM components must be connected to hardened stainless steel for tissue biopsy or dental tools. In other cases, electronic components are compressed in the tool and must be sealed in the equipment, and the welding is required to be smooth and not damage the components.

　　Laser welding is suitable for all these devices, because laser welding can achieve smooth sealing. Laser welding generates a small amount of heat, and the welding position can be very close to polymer seals, glass-to-metal seals, welding components, and electronic circuits. It can also be used for welding leads and connecting wires.

　　Most of the non-implantable medical tools are 304L stainless steel. It is easy to weld, does not produce cracks, and is not prone to corrosion in the welding area like high-carbon stainless steel alloys. Sometimes other alloys are used, such as high hardness stainless steel like 440C or 430, and sometimes titanium alloy Ti6-4 is used. As long as the correct welding method and alloy combination are used, all of these are weldable.

　　 Surgical tools, such as biopsy tools, use laser welding to connect shaft pins to components and solder components to leads. Dental appliances use laser welding in a wide range, from grinding to the manufacture of tool shells. When assembling, the small vascular clip is welded by laser, and a smooth and consistent weld seam is required on this delicate tool. Stents, cardiac catheter components, and other arterial treatment tools will be assembled by laser welding. In order to facilitate X-ray inspection, an X-ray opaque mark was added to the component. Rigid endoscopes often use stainless steel tubes, which are sealed with lasers between the tubes, and laser sealed at the coupling position. In most cases, the weld seam of laser welding is smooth, without porosity, and can be welded repeatedly. It can be used in situations that require less deformation and autoclaving.

　　Pulsed YAG laser is the best choice for medical equipment welding. They have high peak power and low calorific value, can solve the problems of different alloys, and can perform fine processing under the condition of maintaining high penetration depth. Optical fiber transmission is the most commonly used, because the consistent focal spot size and energy distribution can help fill various gaps with corner joints and butt joints, and get a good nugget diameter during large-scale welding. And the small focal spot range is kept within 40-60um. For high-volume welding that requires fast speed, continuous lasers and super-mode YAG lasers are the best choices.