We carried out a study on the optimum amount of copper powder to be added with the aim of improving fluidity and solder dispersal by adding copper powder. The results clarified that consistent dispersal of solder can be achieved with the addition of 5 vol.% of copper powder, and addition of more than this amount is disadvantageous. The copper powder reacts with the solder during kneading, and appears smaller or disappears altogether. However, it was found that even though the copper powder appears to have decreased in size, it still functions as a dispersal agent. It was also confirmed that the size of the dispersed solder is about 25μm, indicating that it can be dispersed finely to 1/4 the size when copper powder is not added. We also investigated the dispersal effects when components other than copper powder were added, and confirmed that copper powder is very suitable as a dispersal agent. One of the reasons for the fine dispersal of the solder is the ease of copper powder to form an alloy with the solder, apparently because of the formation of a solid solution of the alloy and copper with the solder near the melting point of the solder. Viscosity measurements and fluidity tests were also performed to investigate fluidity and appropriate conditions were shown. We also performed wiring injection of a solid body with a width of 0.05mm based on a 2-shot molding model and confirmed that fluidity was excellent.

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Thermoplastic elastomers possess properties of both rubber and engineering plastics. The most important feature of these materials is the combination of the incompressibility and flexibility of rubber with the rigidity of engineering plastics. Thermoplastic elastomers can be employed in a wide variety of applications where small deformation is repeatedly applied. Attempts are underway to elucidate the properties in the region of large deformation in order to respond to demands for ensuring the integrity of structural components under extreme conditions such as impacts and collisions.
In this report, we focused on the cylindrical molding of thermoplastic elastomers, and compressive deformation behavior in static compression tests where buckling was observed. The effect of the molding shape on the load-displacement behavior was examined.
The following results were obtained;
(1) The buckling deformation behavior of the cylindrical molding changed with the shape of the molding.
(2) The load-displacement behavior was able to be controlled by a change of inner diameter and outer diameter of the molding.

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Stable pellet-conveyance around the feed throat of the heating cylinder of an injection molding machine is an especially important element in precision molding. In this study, we observed the pellet-conveying behavior of several resins using simultaneous visualization equipment for both the feed throat area and the heating cylinder in order to clarify the mechanism for the occurrence of unstable pellet-conveyance in PBT. Moreover, we studied the correlation between the friction coefficient and temperature of the pellets using a friction measuring machine, and obtained the following results
(1) The visualization experiment confirmed that PBT pellets have a small axial velocity component and a large rotational velocity component compared with other resins, and showed an unstable velocity distribution with changes in the screw revolution rate. When the screw stagnated during the charging process, an airspace occurred temporarily in the solid-conveying area of the heating cylinder. At the same time axial velocity component of the pellet decreased while the rotational velocity component increased.
(2) The friction measurements confirmed that the friction coefficient of the resin pellet depends mainly on the temperature. Moreover it was shown that the reverse motion of the screw during the charging process forms an inverse temperature area where the temperature of the screw surface becomes higher than that of the inside wall surface of the cylinder. From these results, it was suggested that unstable pellet-conveyance in PBT results from the changes in friction force balance in the solid-conveying region due to the both of the temperature reverse and the singularity of friction coefficient of PBT.

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