This study was performed to investigate the mechanism underlying the deposition process in powder jet deposition (PJD). To examine the process of deposition, fractured HA particles were retrieved and observed by transmission electron microscopy (TEM). The untreated powders were polycrystalline, consisting of crystal grains 0.5 - 1.0μm in diameter, while the retrieved fractured particles consisted of nanometer-order crystal grains. Strain analysis of the particle interior showed that these minute crystal grains exist in the area of high stress, where the particles are colliding, and suggested that they appear as densely packed regions in deposited films. On the other hand, sparse regions exist in the boundary regions of the densely packed regions, suggesting that the efficiency of deposition is a function of the size of polycrystalline regions of nanometer-ordered crystal grains. Moreover, the ratio of deposition of one particle was estimated to be 6.57% using a classical molecular dynamics (CMD) method and a smoothed particle hydrodynamics (SPH) method.

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We developed a wireless communication holder system to monitor the process temperature and vibration of a rotating machining tool. We examined the expansion of function for monitoring of multiple processing phenomena while sharing a wireless communication circuit. This report presents estimation of the process temperature in end-milling and the chatter vibration when boring. The thermocouple was set in the end-mill tool to measure the process temperature, and the MEMS accelerometer was set in the boring tool to measure chatter vibration. We also present an investigation of end-mill temperature observed by infrared thermography and vibration of the spindle using a traditional accelerometer. The proposed holder system was effective for estimating process monitoring of rotating machining tools.

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This study was performed to clarify the melting and joining process by pulsed laser irradiation of a single metal particle, which is the minimum unit of laser additive manufacturing. Here, we used pure titanium substrates and pure titanium powders, and performed pulsed laser irradiation of an unfixed Ti particle on the substrate. Using a high-speed camera, we observed behavior in which the Ti particle was welded to the substrate by this laser or the Ti particle was repelled by the laser. The results indicated that metal vapor pressure arising from local temperature increase and surface tension by melting of the Ti particle are important elements for joining an unfixed Ti particle.

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