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ADVANCED MANUFACTURING PROCESSES Proff. Strano – Annoni – Demir SURNAME NAME PERSONAL ID Exam – 21st January 2022 Question n. 1 Concerning the active fiber laser with CW emission, which of the following statements is wrong? ‐ The pumping medium is diode laser ‐ The laser beam resonates between the Bragg gratings ‐ The double clad fiber allows to couple the pumping light with the active core more efficiently ‐ The high surface to volume ratio of the active medium is disadvantageous for the heat dissipation and reduces the beam quality ‐ Multiple modules of active fiber lasers can be coupled to a larger delivery fiber to increase the laser power Question n. 2 Concerning the pulsed wave laser‐material interaction mechanisms, which of the following combinations are industrially viable? ‐ Wood marking with a pulsed CO2 laser ‐ Glass cutting with a µs‐pulsed single mode fiber laser ‐ Full penetration welding of 3 mm Al‐alloy with a fs‐pulsed fiber laser ‐ Surface hardening of 10 mm mild steel with a ps‐pulsed disc laser at second wavelength harmonic ‐ Engraving of silver with a ms‐pulsed Nd:YAG laser Question n. 3 You are carrying out a laser paint stripping process on e‐drive hairpins operating with a 500 W ns‐pulsed CO2 laser source. The material is a white polymeric enamel paint with 0.1 mm thickness on copper pins with a rectangular cross‐section of 4 mm x 2 mm. You have carried out single track incisions on the material with the maximum speed of the scanner head and the maximum laser power, then measured the incision width. You employed the point heat source to estimate the hatch distance and the number of passes. You verified the feasibility of the determined parameters, observing incomplete enamel removal. Which of the following can be a plausible cause? ‐ The…