“Additive Manufacturing” became one of the most common words in manufacturing since 2013. Additionally, the technology is familiar not only in manufacturer community but even in public as “3D printing” since then, and expectation to this technology is expending rapidly and dramatically. In this paper, principles of those categorized by “additive manufacturing” are roughly explained. Advantage and drawback of these technologies behind the recent big boom is described followed by their characteristics and potentials.

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The paper reviews technology developments and market trends surrounding Additive Manufacturing (AM, also known as 3D Printing), which has received much interest and attention in the past year from variety of audiences both industrial users and non-industrial users. The paper will also explain the development history and characteristics of RaFaEl, an original Japanese powder bed fusion system developed by Aspect, Inc. Major focus of development was to improve productivity from Aspect’s previous powder bed fusion systems by two times.

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Laser Additive Manufacturing (LAM) is a rapid manufacturing technique capable of producing complex three-dimensional parts rapidly from CAD (computer aided design) models by melting or sintering successive thin layers of powder with a laser beam. LAM with metallic powders is widely adopted in the industrial world as an effective method for the trial or direct manufacturing of molding dies with inner cooling channels and complex mechanical parts, particularly in the automobile and aerospace industries. LAM is also available as an attractive option in the medical world for the fabrication of various tailor-made implants. This review article introduces the principles, characteristics, and technical trends of the LAM process. We also present partial results from our research into LAM processes using carbon steel powders and titanium powders to fashion extremely strong materials and metallic biomaterials, respectively.

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Additive Manufacturing (AM) is attracting attention as a breakthrough technology in advanced manufacturing. In this paper, we describe the present state of the development of 3D printers for metals. AM technology, however, has issues that must be resolved: product accuracy, surface roughness, building volume, build-up rate, and so on. A national project, which was launched by the Japanese government in April 2014, is dedicated to the development of innovative 3D printers with electron beam and laser beam systems as well as the development of powder bed fusion and directed energy deposition processes. We introduced our ambitious objectives and the project’s potential.

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We established a method to calibrate the responsivity of a terahertz (THz) detector using a standard blackbody furnace and terahertz filters including metal-mesh low-pass filters, a z-cut crystal quartz plate, and black polyethylene sheets. The basis of our method is to determine the incident energy to a detector by Planck’s radiation law, the transmittance of THz filters and SΩ, and the product of the area and the field of view (FOV) in an optical system of measurement. We confirmed the reliability to calibrate the responsivity without any effects by changing the blackbody temperature from 600 to 1000 K. In this study, we calibrated the sensitivity and the NEP of four THz pyroelectric detectors operated at room temperature in three frequency-band conditions (3 THz low-pass, 2 THz low-pass, and 1.5 THz bandpass) and obtained the reliable sensitivity and the NEP of the THz detectors to compare them.

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We demonstrated a high-power SHG green laser that utilizes a high-power Yb fiber laser and a Z-cut Mg-doped stoichiometric LiTaO3. This high-power green laser has many advantages, such as compactness, light weight, and low power consumption as well as full air cooling by a single pass configuration. Furthermore, it has high beam quality and high-power stability. The incident infrared light and the generated green light have high beam quality with M2 < 1.1 for double emission to the air. These beams can be focused at same point with a near diffraction limit spot size, and this laser is expected to be a new tool for laser processing.

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We performed simulation experiments to detect defects in a vibrating concrete structure by running loads using a laser differential interferometer. In laser interferometry, it is difficult to acquire vibration information when the amplitude of the out-of-plane vibration is big enough in comparison to the working wave length because the interference signals repeat bright and dark as different frequencies of actual vibrations. In this paper, we performed interference measurements using scattered light from an inspected object as a signal and a reference beam to reduce the relative displacement. Our results show that artificial inner defects in samples under environmental vibration can be detected.

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