Takayuki Kamitani

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.

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.