The Research Of Sealing Glass Ampoule By CO₂ Laser

In the medical packaging industry, because the glass has superior protection performance and good chemical stability, the vast majority of injection drug use ampoule for packaging. As the laser processing has the advantages of high energy density, non-contact processing and not exist the problem of pollution, it is considered as an ideal heat source for sealing ampoule.In order to sealing ampoule by CO2 laser. First, the thesis simulated the three-dimensional temperature and stress field in the process of sealing ampoule using the large-scale finite element software ANSYS. The influences of the power, beam size, speed of rotation, laser mode on the temperature and stress field have been analyzed. Comparing the influences, proposed a optimum sealing programme. i.e., first of all, using CO2 laser preheat the ampoule, and then adding another CO2 laser radiation that the center of beam has a certain distance from the No.1, the ampoule melted and sealed. Finally, retain the low power Laser during the cooling process in order to reduce the thermal stress.The main research and conclusions are as follows:(1) The thesis discussed the current situation of the research on the laser sealing and laser sealing glass. Explored the interaction mechanism between the laser and material, especially emphasised on its heat transfer and thermal elasticity theory. Finite element method and ANSYS software were also introduced.(2) The moving Gauss function distribution heat source was successful loaded in the cylindrical surface. Obtained the three-dimensional dynamical temperature field in the process of sealing ampoule by laser. The influences of wall thickness, rotating speed, laser mode and other factors on the temperature distribution were analysed. The results is as follows: when the ampoule is at critical speed, cylindrical surface temperature has nothing to do with the speed, temperature gradient of laser heating stage was significantly higher than that of the cooling stage.(3) The stress field was obtained on the basis of the three-dimensional dynamical temperature field. The results is as follows: the central area of the laser beam is stress in heating stage, while is tensile stress in the cooling stage, thermal stress in the cooling stage is about half smaller than that in the heating stage; In the axial direction, stress decreases at first, and then rises, and decreases at last; In the radial direction , stress decreases at first, and then rises. Thermal stress is mainly constituted by the Axial direction part.(4) Carried out experiment and successfully sealing ampoule by CO2 laser. Two bouquet of laser, which center has a certain height difference, can effectively increase melting capacity and improve the success rate of sealing. As some ampoules have the defects that the irregular shape and uneven thickness in sealed place, cold crack after sealing can't avoid.