| 摘要 |
The invention relates to an automatic installation for laser beam welding and to a process for using the same, meant to seal the capsules with radioactive content used both in radio-therapy consulting rooms for treating malign tumours which use radioactive sources of Co-60, Ir-192, I-125 or Y-90 and for industrial applications in units of industrial gammagraphy, non-destructive control and monitorization of industrial processes which use radioactive gamma-emitting sources of Ir-192, Co-60, Se-75 or Cs-137. According to the invention, the installation consists of a laser source (1), a welding head (2) connected to the laser source (1) through an optical fiber (3), a camera (4), a positioning system (5), a control unit (6) provided with a joy-stick (7) by means whereof the radioactive capsule (8) is handled inside the hot chamber (9). As claimed by the invention, the process starts by cleaning the capsule (8) by immersing the same, for 30 min, into a vat subjected to ultrasounds, which comprises, at the beginning, an acetone solution, then a propanol or ethanol solution, followed by introducing the capsule (8) inside the hot chamber (9) by using the joy-stick (7) and fastening the same in the system (5) for positioning the welding installation where the proper welding occurs, without addition material, by melting, in a controlled way, the body edges and the capsule cover, the laser source (1) using an energy E = 1.66...2 J, a top power P= 1...1.2 kW, a laser pulse duration t = 2.5 ms., an average power P= 33.1...40 W with the laser pulse frequency f = 20 kHz and a total number of pulses in the laser sequence Np = 104, at a rotation speed of the capsule (8) Vr = 0.2 rot/s. |
