This paper presents automation technologies with articulated robots applied in the foundries. The work environment in the foundry is tough because of dusty and high temperature environment. Therefore, the application of automation technologies has been promoted in the foundry industry. However, the automation technologies to high-mix low-volume production and production of large-sized casts have been less-advanced. In the view point of a shrinking workforce, it is required to develop the automation technologies with articulated robots which can be utilized for such productions.

  In this paper, the considerations in the construction of automation technologies with robotics system are outlined for promoting the development of the robotics technologies applied in the foundry. Furthermore, the seminar for discussing the robotics technologies utilized in the foundry, which will be held from the beginning of 2022, is introduced.

  This paper discusses a robot teaching system for scraping motion in a sand molding robot system using a vertical articulated robot. Sand molding robot systems for making self-hardening molds are increasingly being developed in recent years. These robots are able to automatically build a variety of sand molds by teaching robot motion for the sand mold making work. However, the teaching work takes considerable time and effort as the user needs to make the path of the robot motion by numerical entry using a teaching pendant as an input device, which makes it difficult to apply this robot system to high-mix low-volume manufacturing processes. In this study, we therefore proposed a simplified teaching system using a touch panel in which the paths of the robot motion can be generated by tapping the desired paths and visualized on the touch panel. It is easy to teach the desired paths to the sand molding robot and teaching work can be performed in a short time. We also focused on developing the teaching system for the sand scraping motion in the sand molding robot. The efficacy of the proposed teaching system was verified through experiments on sand scraping motion using the vertical articulated robot.

  In order to reduce distortion after heat treatment, we investigated high vacuum die casting samples of Al-Si-Mn-Mg-Cr-Cu alloy after T6 tempering by solutionizing at low temperature. The distortion caused by water quenching (W. Q.) was larger than that by air quenching (A. Q.), and decreased with decreasing solutionizing temperature. We successfully reduced distortion by attaching a stainless steel tool to the die cast sample. In this report, the distortion of the sample after T6 tempering was the smallest when solutionizing (440℃-3 hour) was carried out in A. Q. and when the tool for reducing distortion was used. The elongation and the 0.2% yield strength of this sample were 16.4% and 139MPa. The microstructure of the sample at low temperature indicated that eutectic Si phase was spheroidized and the elongation of the sample was greater than the as cast sample. The quantitative analysis results of the α Al phase of the sample showed that most of the Mg in the alloy had solidified into the α Al phase. Si precipitation was also seen in low temperature solutionizing. The iron compounds of the samples were composed of Al, Si, Fe, Mn, Cr and Cu. Comparison of the 5 mm thickness sample with 3 mm thickness sample indicated that the 0.2% yield strength difference was less when T6 tempering was carried out by solutionizing at a low temperature compared to when as cast.

  Thermal expansion characteristics and static mechanical properties of 24%Ni-12%Co-2%C-1%Si low thermal expansive spheroidal graphite cast iron were investigated by varying the amount of martensite by changing cooling rates from 1173K of solution treatment temperature. The microstructure of the as-cast sample consisted of graphite and matrix of 50% martensite and 50% austenite, and its coefficient of thermal expansion was about 6 × 10^-6/K at 373K. The coefficient of thermal expansion of the sample, which was subjected to solution treatment, dropped to about 4 × 10^-6/K owing to inverse-transformed austenite from martensite. The amount of martensite changed with the cooling rate and it increased when cooled slower than air cooling. The critical cooling rate for martensitic transformation was determined to be about 1 K/s from observation of microstructure and change of coefficient of thermal expansion. The coefficient of thermal expansion at 373K of the samples with higher amount of inverse austenite became lower because the martensite suppressed Invar effects which contribute to low thermal expansive characteristics. Therefore, the coefficient of thermal expansion at 373K depended on the amount of martensite. The tensile strength and hardness of the samples increased with increase in the amount of martensite and tensile characteristics was found to be greatly affected by change with the amount of martensite. However, as elongation of the samples was 2 to 5% regardless of the amounts of martensite or austenite, materials characteristic included poor ductility.