Yoji Marutani

Development of 5-Axis Friction Stir Welding System

A friction stir welding system with the flexibility of five axes has developed to join 3-dimensional curved surface. The features of the hardware of this system are: (1) the tool pressurization by an air cylinder is adopted. (2) In order to use for various researches, it has two kinds of FSW tool heads. (3) A 3-dimensional coordinate measuring instrument is installed to teach the weld line. The features of the software for this system are: (a) weld line is taught after a work piece is set on the table, (b) the control program is described by NC language, (c) the edition of welding conditions and the simulation of the tool path are available. This paper reports the structure and features of the system, and examples of FSW by the system

Manufacturing sacrificial patterns for casting by salt powder lamination

The increasing use of rapid prototyping (RP) which fabricates complicated models easily, has highlighted the desire for making metal models also with RP technology. However, direct RP technology for metal models is not established yet. This paper presents a technology for manufacturing sacrificial patterns using salt powder. By soaking in water the salt patterns can be removed from moulds very easily. They are converted to metal models very easily through investment casting. The feasibility of the method was examined by laminating salt powder with 3D printing method. In the preliminary test it turned out that pure salt powder is unsatisfactory. So flour was mixed with salt powder for the absorption of the binder, because it is insoluble in water and readily available at low cost. Controlling the mixing ratio tests were made to examine the quality of the salt patterns, and showed promising results not only as sacrificial patterns but also as conventional 3D models. Then metallic models with complicated shapes were fabricated by casting in plaster using these salt models as patterns, and it was proven that these salt models can be used in investment casting as sacrificial patterns.

Analysis of perplexing situations in word processor work using facial image sequence

Computer users often feel difficulty in operating. For this reason, it is desirable to make the computer detect the operators perplex situations and carry out the kindness action to the operator. We propose the method for recognizing the perplex situations in word processor work. Firstly, the perplexed behaviors were picked up by observing the subjects in word processor work. As the result of the observation, it was made clear that the perplexed behaviors were shown in the motion of the head and keyboard operation rather than facial expression. Secondly, the head motions in x, y, z and (Theta) directions were captured in real time by chasing both pupils through the use of image processing. In the system, the processing speed is enhanced by reducing image data. The behaviors are converted to the series of vectors which have the moving speed of head. Thirdly, the distances between unknown input motion patterns and the template patterns of the vector sequences were calculated by DP matching. As the result of DP matching, it was made clear that each head motion was identified. The proposed method can be applied to the development of the software which responses automatically when the operator falls into the perplex situations.

Application of UV laser fabrication to organ models interpolated from computed tomography and magnetic resonance images

We have developed a unique laser fabrication system that uses an ultraviolet laser beam and liquid photopolymer. The system can easily be used to fabricate physical models without milling tools in only one process by using digital data obtained from medical computed tomography (CT) scanners or computer-aided design systems. We describe the fabrication of a smooth physical model such as a cerebrum, using the laser fabrication system, with the help of CT and magnetic resonance images that are made with coarse slices. Each sandwiched area between adjoining images is interpolated by using third-order spline curves in the cylindrical coordinate system. This modeling technique can play a major role in personal prosthesis, surgical planning, and implant design.

Influence of Contineous Transversal Inclination of Tool on FSW Joints

The influence of roll angle of the FSW tool rotation axis on tensile properties of joints was examined to clarify the allowance of deviation from proper tool posture for three-dimensional friction stir welding. A5083-O plates of 3 mm in thickness were butt welded by three-dimensional controlled FSW machine. Transversal inclination of the tool (roll angle of the tool) was continuously changed from 0 degrees to 10 degrees for both sides. Butt joints ruptured at base metal within the range of roll angle of the tool plus/minus 2 degrees, and ruptured at the thin part made by inclined tool shoulder entering in the range by plus/minus 7 degrees. Over the range of plus/minus 7 degrees, butt joints ruptured at elongated cavities made by tool inclination at the border of stir zone and base material.

Selection of Binder Materials for Salt Powder Lamination

A new technology for manufacturing expandable salt patterns to fabricate metallic parts by investment casting is presented and the results of experiments are reported to find out the binder substances suitable for the method. Solid models made by this method are also reported.

Overview of FSW Project in Osaka East Urban Area Industry-Government-Academia Collaboration

Friction Stir Welding (FSW) for aviation and automobile applications has been investigated at Osaka East Urban Area Industry-Government-Academia Collaboration Project on FSW sponsored by a Japanese ministry of education, culture, sports, science and technology, 2004-2007. The objective of this project is the three dimensional (3D) FSW of light metallic materials. The project consists of two simultaneous investigations. One is the approach from material side. The establishment of optimum FSW conditions and the construction of the FSW equation between weld condition and formed microstructure. The other is the approach from 3D software. The construction of optimum algorism for 3D FSW is the main theme. The construction of 3D FSW expert system for aluminum alloys, magnesium alloys and titanium alloys is the goal of us in combination of the results developed by the two research group.