Medical Devices - Medical Tool Welding
Tools probes and leads used in medicine must be fabricated from different alloys depending upon their end use. They must be joined with smooth welds without pores so they can be sterilized in an autoclave time and time again. In some cases they are very small, requiring an almost microscopic weld. OEM components must be joined to a hardened stainless steel for tissue biopsies or as dental tools. In other cases there are electronic components encapsulated in the tool that must be hermetically sealed in the device with a smooth weld without damaging the components.
Laser welding works for all of these applications as a laser weld produces a smooth hermetic seal. Laser welding has very low heat input and can be placed very close to polymer seals, glass-to-metal seals, soldered components, and electronic circuits. It can also be used to weld leads and feed-throughs.
For most medical tools that are not implanted the alloy of choice is 304L stainless steel. It is easy to weld, has no cracking issues, and does not corrode near the weld zone like higher carbon content stainless alloys. Other alloys are sometimes used such as higher hardness stainless steels like 440C or 430 and some titanium alloys like Ti 6-4 but all are weldable when the right procedures and alloy combinations are used.
Surgical tools such as biopsy devices use laser welds to attach axle pins to components and to weld the assembly to a lead. Dental tools will use laser welds from the actual grinding portions to the housings and shells of the tools. Very small vascular clamps are laser welded during assembly for smooth consistent welds on very fine features. Stents, cardiac catheter assemblies, and other arterial therapy tools will use laser welds for assembly and to add x-ray opaque markers to the components for easy x-ray viewing during the procedures. Rigid endoscopes are often assembled from stainless steel tubes with hermetic laser welds at the tube transitions and where feed-throughs are placed on the device. In most cases the laser welding produces the smoothest, pore-free, repeatable welds for minimum distortion as well as reliable autoclave sterilization.
Pulsed YAG lasers are the best choice for medical tool welding. Their high peak powers and low heat input can handle all the different alloys and create a very tolerant process while maintaining very fine welds up to deep penetrations. Fiber optic beam delivery is most common for these parts because of the consistent focus spot size and top-hat energy distribution which helps with fillet and butt joints to fill any gaps and get good weld nugget size for maximum yield in large welds but also the consistently small focus spots for very fine welds in the 40-60um range. For high volume welding where high speed is important CW and Super Modulated YAG lasers are the most capable.
Typical lasers that have been used for this application
JK125P, JK300P & JK300HP
For Fiber-Delivered Cutting, Welding, Heat Treating
JK401SM & JK501SM
Lamp-Pumped Nd:YAG, 400 & 500W, 800 & 1000 with SuperModulation
JK450HP & JK600HP
Lamp-Pumped Nd:YAG, 450 & 600W
Please call us to discuss lasers for your specific application
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