Abstract: In electric resistance welding for energizing a workpiece formed by superimposing plural metal plates, an energization resistance reduction amount between a pair of electrodes pressurizing the workpiece is detected at a specified time interval during each welding process under a specified welding condition, frequency distribution of the energization resistance reduction amount under the welding condition is calculated on the basis of data relating to the energization resistance reduction amount, the frequency distribution is fitted with a Gaussian function, and occurrence of an expulsion under the welding condition is determined on the basis of whether the fitting is statistically significant.

Abstract: In a frictional spot joining where plural metal members lapping over are jointed with a joining device comprising a rotating tool, a receiving tool disposed on a rotational axis of the rotating tool and a drive device to rotate and move the rotating tool in a pushing direction, a holding member is provided on a side of the receiving tool, which has a restriction portion to restrain a movement of the receiving tool in a direction perpendicular to the rotational axis, and the joining device is moved by a moving device such that the receiving tool is disposed at the restriction portion. Accordingly, the rotational runout of the rotating tool can be restrained effectively with a simple structure of a properly small-sized rotating tool and receiving tool.

Abstract: To provide photosensitive composition for volume type hologram memory with superior photosensitivity and large differences in reflective index before and after photo-curing and with controllable curing shrinkage. The photosensitive composition for volume type hologram memory of the present invention comprises a photo-curable volume expansion compound and a photoinitiator. According to the photosensitive composition for volume type hologram memory of the present invention, a composition of superior photosensitivity and large differences in reflective index before and after photo-curing and controllable curing shrinkage with photo-curable volume expansion composition can be provided.

Abstract: In the third step of joining of the metal members, the pressing force of the rotational tool under rotation is maintained at the third pressing force that is smaller than the second pressing force until a specified period of time elapses after the tip of the pin portion of the rotational tool has reached the specified point that is at a distance from the joining face. Accordingly, the proper plastic flow of the metal member can be generated and thereby the joining strength with a sufficient period of time of agitation can be ensured, by maintaining a high temperature enough to soften the metal member and by preventing the rotational tool from coming into the metal member too deeply or from penetrating the metal member.

Abstract: In a frictional spot joining where plural metal members lapping over are jointed with a joining device comprising a rotating tool, a receiving tool disposed on a rotational axis of the rotating tool and a drive device to rotate and move the rotating tool in a pushing direction, a holding member is provided on a side of the receiving tool, which has a restriction portion to restrain a movement of the receiving tool in a direction perpendicular to the rotational axis, and the joining device is moved by a moving device such that the receiving tool is disposed at the restriction portion. Accordingly, the rotational runout of the rotating tool can be restrained effectively with a simple structure of a properly small-sized rotating tool and receiving tool.

Abstract: The first and second metal members are joined by being pushed against the interposed member by the rotating tool in a state in which part of the surface of the second metal member corresponding to the joining portion contacts the contacting face of the interposed member that has a larger area than the an area of the tip of the rotating tool. Thus, the first and second metal members can be pressed against the receiving tool of the joining gun via the interposed member. Accordingly, there can be provided a high-quality superior joining product.

Abstract: In the third step of joining of the metal members, the pressing force of the rotational tool under rotation is maintained at the third pressing force that is smaller than the second pressing force until a specified period of time elapses after the tip of the pin portion of the rotational tool has reached the specified point that is at a distance from the joining face. Accordingly, the proper plastic flow of the metal member can be generated and thereby the joining strength with a sufficient period of time of agitation can be ensured, by maintaining a high temperature enough to soften the metal member and by preventing the rotational tool from coming into the metal member too deeply or from penetrating the metal member.