Inspection of 3D prints using 3D scanners becomes important as the range of applications of 3D printing becomes greater. Since the typical 3D printing is layer-by-layer manufacturing, a layer-by-layer inspection is intuitive for 3D prints. However, the posture of the object in the scan data is unknown, so we need to estimate the build direction first to locate the positions of layers. In this research, we use X-ray computed tomography to investigate the geometric features of the 3D print made by Fused Deposition Modeling and provide a method to estimates the build direction of 3D print based on the features. A rough estimate of the build direction is obtained first based on the complete shape. Then, we remove the unpredictable parts of the 3D print based on the rough estimation and achieve accurate estimation based on the remaining parts. By checking the slices perpendicular to the estimated build direction, a layer-by-layer inspection is achieved where the user can investigate the interior structure of the 3D print. The proposed method lets the build direction can be estimated only based on the scan data, which makes the layer-by-layer inspection available for 3D prints without prior knowledge (e.g., CAD model).

Throwing is one of the most impotent activities in day-to-day life and for sports. This research focuses on developing a motion tracking system for detecting and analyzing short distance throwing motions and analyze the accuracy. Intel Realsense D415 camera was used as depth camera hardware. Nuitrack Software Development Kit combined with Open CV written in C++ was used to track skeleton position accurately. A simple throwing task is given to eleven volunteers to evaluate the accuracy of the system. The throwing task was to throw a tennis ball into a wastepaper bin by using the dominant hand. Distance of 1.5, 2, 3, 4 meters was given to each person to throw the ball accurately fifteen times per one distance. A tennis ball integrated with a touch sensor and a Bluetooth module was used to measure the ball's releasing point. For each throw, the shoulder angle and angular velocity of the ball releasing point were taken. The data collected and the data calculated by a mathematical model were compared to check whether the system is giving accurate data. Statistical analysis was done to measure the accuracy of the system.

In general machining process representation methods, three-dimensional (3D) geometric models and its motion according to time series information are commonly used to represent dynamic machining. But the tool-workpiece engagement determination based on 3D geometric models is not flexible enough, for high accuracy it needs huge amount of discrete data to get the result which decreases the efficiency. In the study, we propose a system to represent tool-workpiece engagement situation of dynamic machining process by four-dimensional (4D) geometric model based on Spatio-Temporal space. For analyzing the tool-workpiece engagement in Spatio-Temporal space, “T-map approach” is used. The T-map is defined as segments along T-axis in Spatio-Temporal which extend from different grids of subdivided 3D workpiece model to the tool-occupied region (TOR). Lengths of T-map segments refer to when the material in corresponding grid is removed by the tool. The core of the T-map approach is to determine whether the T-map segment and the tetrahedron in TOR intersect and return the length of the T-map segment. Checking process of all segments and tetrahedrons requires a lot of computing resources. Therefore, parallel processing based on GPGPU is introduced for accelerating repeated computing process in T-map.

The EMAF (Magnetic Abrasive Finishing combined with Electrolytic) process was proposed in order to improve the finishing efficiency of traditional MAF (Magnetic Abrasive Finishing) process. For the purpose of making EMAF process more widely used in industry, the machining mechanism of the EMAF process for finishing Aluminum Alloy A5052 has been discussed in this paper. In the experimental part, firstly the finishing effect of electrolytic reaction and MAF process in EMAF process are explored respectively. Then the compound EMAF processing experimental is conducted. The processing stability of the EMAF process is evaluated by the measured processing current value curve. By adjusting the amount of iron powder to improve the EMAF processing stability, and the occurrence of short circuits can be avoid effectively. In this study, the best experimental results were obtained when using the electrolytic iron powder of 330 μm (in mean diameter) and the amount of 0.5 g.

In order to achieve the finishing of micro complex surface, a magnetic abrasive finishing process using an alternating magnetic field is proposed. In the alternating magnetic field, the periodic change of the current will cause the magnetic cluster to fluctuate up and down, which can not only continuously mix and update the abrasive particles, but also periodically adjust the shape of the magnetic cluster to better fit the surface of the workpiece. In this paper, the influence of the combination of alternating magnetic field and static magnetic field on the magnetic field and magnetic cluster is analyzed. The feasibility of this method for finishing micro complex surface is investigated. Through the observation of magnetic cluster, it is found that in the combined magnetic field, the fluctuation amplitude of magnetic cluster increases. At the same time, through the measurement of magnetic flux density, the combined use of alternating magnetic field and static magnetic field increases the magnetic flux density in the finishing area. The experimental results show that this method has the feasibility of finishing micro complex surface and has deburring effect.