Laser plastic welding technology in the medical field

Adhesives that meet biocompatibility requirements and FDA approvals are difficult to find in the medical industry. In addition, the low surface energy of many commonly used plastics, such as PP, PE, and PTFE, also makes it difficult to bond with adhesives. Adhesives are often used as a quick, temporary solution in prototyping. However, in subsequent full-scale production, there are a number of factors to consider, such as cost, process efficiency, safety, environmental protection, bond strength, etc. Laser bonding of plastics is a cost-effective way to provide good consistency, high strength bonds, no additional consumables, and no environmental concerns.

Regarding the influence of material selection on welding performance: the selection of welding materials, thermoplastics and modified plastics are used for laser welding. But in addition to the basic resin properties in the material, but also includes colouring agents, fillers have been punch modifiers, etc., these compositions together affect the effect of welding. Generally, the filler content is kept below 30 per cent to ensure welding strength. In addition two pieces of material combination, must ensure that there is a similar melting point and viscosity, to ensure that the intermolecular diffusion to complete the welding.

Common transmission welding of the lower material needs to absorb light or partially absorb light, the upper material transmittance of not less than 25% (refers to infrared light transmission). Another little-known welding method double transparent plastic laser welding this year, the medical field is also more and more widely used. Double transparent material transmittance are in 80% or more, the traditional plastic laser penetration welding using laser wavelength is generally in the 900-1000nm, in this band of transparent plastics for the laser absorption rate is very low, but take 2000nm or so of the band of laser to ensure that transparent plastics such as PC, PMMA, etc. can absorb the laser's energy, with a very short focal length of the laser head will be the focus of the light beam into a spot, the focus of the laser is in the weld. The focal point of the laser is at the weld seam, because the focal point has enough energy density, without flux, can melt the transparent plastic to complete the welding. Common applications include capsule housings for endoscopic gastroscopes, blood analysers, microfluidic channels, disposable infusion solutions, and tubes for medical electronics.

The 2000nm laser plastic welding head developed by Songsheng Optoelectronics according to the market demand of medical industry is equipped with the leading thermostatic semiconductor laser and built-in temperature feedback system, which can directly control the temperature of the welding joint and present the welding temperature curve in real time to ensure the welding yield. Its process can replace the traditional adhesive process techniques, specifically for welding plastic products in the medical field.

About the strength of laser welding, performance. Compared with the traditional hot plate welding, ultrasonic welding, laser welding using non-contact welding, in addition to welding products, beautiful, no trace, welding precision, solid and sealed airtight and watertight and other advantages, laser welding welding has the process of resin degradation is less, resulting in fewer debris, there are advantages of residue. For welding processes that rely on surface friction to generate heat, such as rotary welding and vibration friction welding, it is difficult to avoid not generating particulate contaminants, as well as loose spills, laser welding without worrying about particulate contamination.

The medical device industry is also one of the important application areas of plastic laser welding technology. Plastic laser welding technology can be applied to the manufacture and assembly of medical devices, such as medical syringes, infusion bags and so on. Plastic laser welding technology has the advantages of fast welding speed, high welding strength and small welding deformation, which can improve the manufacturing efficiency and quality of medical devices.

In the future, with the aging of the population, the development of the medical device industry will be further promoted. The application of plastic laser welding technology in the medical device industry will also be further developed. In addition, plastic laser welding technology can also be applied to the disinfection and cleaning of medical devices, through welding technology to achieve efficient disinfection and cleaning of medical devices, to improve the hygiene and service life of medical devices.