Spectroscopic closed loop control of penetration depth in laser beam welding process

Abstract

TNO, together with its partners, have designed a cryogenic scanning mechanism for use in the SAFARI 1 Fourier Transform Spectrometer (FTS) on board of the SPICA mission. SPICA is one of the M-class missions competing to be launched in ESA's Cosmic Vision Programme 2 in 2022. JAXA 3 leads the development of the SPICA satellite and SRON is the prime investigator of the Safari instrument.The FTS scanning mechanism (FTSM) has to meet a 35 mm stroke requirement with an Optical Path Difference resolution of less then 15 nm and must fit in a small volume. It consists of two back-to-back roof-top mirrors mounted on a small carriage, which is moved using a magnetic bearing linear guiding system in combination with a magnetic linear motor serving as the OPD actuator. The FTSM will be used at cryogenic temperatures of 4 Kelvin inducing challenging requirements on the thermal power dissipation and heat leak.The magnetic bearing enables movements over a scanning stroke of 35.5 mm in a small volume. It supports the optics in a free-floating way with no friction, or other non-linearities, with sub-nanometer accuracy. This solution is based on the design of the breadboard ODL (Optical Delay Line) developed for the ESA Darwin mission 4 and the MABE mechanism developed by Micromega Dynamics.During the last couple of years the initial design of the SAFARI instrument, as described in an earlier SPIE 2010 paper 5 , was adapted by the SAFARI team in an evolutionary way to meet the changing requirements of the SPICA payload module. This presentation will focus on the evolution of the FTSM to meet these changing requirements. This work is supported by the Netherlands Space Office (NSO).

Research on laser selective intelligent processing based on coaxial spectral monitoring

“…According to the spectral wavelength band and intensity, the type and content of material elements can be accurately analyzed. The property and process of laser processing material removal can be monitored online, and the laser processing parameters and status can be controlled by closed-loop feedback according to the type and content of elements, then the selective intelligent processing of multi-layer materials was finished [18][19][20] . E-mail: yangguiyang1020@163.com…”