Abstract: Use of Pb-free solder has become essential due to the environmental problem. A power module is formed by soldering substrates with large areas. It is known that in Sn-3Ag-0.5Cu which hardly creeps and deforms with respect to large deformation followed by warpage of the substrate, life is significantly shortened with respect to the temperature cycle test, and the conventional module structure is in the situation having difficulty in securing high reliability. Thus, the present invention has an object to select compositions from which increase in life can be expected at a low strain rate. In Sn solder, by doping In by 3 to 7% and Ag by 2 to 4.5%, the effect of delaying crack development at a low strain rate is found out, and as a representative composition stable at a high temperature, Sn-3Ag-0.5Cu-5In is selected. Further, for enhancement of reliability, a method for partially coating a solder end portion with a resin is shown.

Abstract: Use of Pb-free solder has become essential due to the environmental problem. A power module is formed by soldering substrates with large areas. It is known that in Sn-3Ag-0.5Cu which hardly creeps and deforms with respect to large deformation followed by warpage of the substrate, life is significantly shortened with respect to the temperature cycle test, and the conventional module structure is in the situation having difficulty in securing high reliability. Thus, the present invention has an object to select compositions from which increase in life can be expected at a low strain rate. In Sn solder, by doping In by 3 to 7% and Ag by 2 to 4.5%, the effect of delaying crack development at a low strain rate is found out, and as a representative composition stable at a high temperature, Sn-3Ag-0.5Cu-5In is selected. Further, for enhancement of reliability, a method for partially coating a solder end portion with a resin is shown.

Abstract: Use of Pb-free solder has become essential due to the environmental problem. A power module is formed by soldering substrates with large areas. It is known that in Sn-3Ag-0.5Cu which hardly creeps and deforms with respect to large deformation followed by warpage of the substrate, life is significantly shortened with respect to the temperature cycle test, and the conventional module structure is in the situation having difficulty in securing high reliability. Thus, the present invention has an object to select compositions from which increase in life can be expected at a low strain rate. In Sn solder, by doping In by 3 to 7% and Ag by 2 to 4.5%, the effect of delaying crack development at a low strain rate is found out, and as a representative composition stable at a high temperature, Sn-3Ag-0.5Cu-5In is selected. Further, for enhancement of reliability, a method for partially coating a solder end portion with a resin is shown.

Abstract: Use of Pb-free solder has become essential due to the environmental problem. A power module is formed by soldering substrates with large areas. It is known that in Sn-3Ag-0.5Cu which hardly creeps and deforms with respect to large deformation followed by warpage of the substrate, life is significantly shortened with respect to the temperature cycle test, and the conventional module structure is in the situation having difficulty in securing high reliability. Thus, the present invention has an object to select compositions from which increase in life can be expected at a low strain rate. In Sn solder, by doping In by 3 to 7% and Ag by 2 to 4.5%, the effect of delaying crack development at a low strain rate is found out, and as a representative composition stable at a high temperature, Sn-3Ag-0.5Cu-5In is selected. Further, for enhancement of reliability, a method for partially coating a solder end portion with a resin is shown.

Abstract: In a changeable chuck system which can grip and release a workpiece by means of a chuck C by itself, fluid shut-off valves 20a and 20b are provided on a fluid supply portion provided on the tip of a main spindle 2 of a machine tool. When the chuck C is mounted on the main spindle 2, the fluid shut-off valves 20a and 20b are automatically connected to fluid couplers 111a and 111b provided behind the chuck C, and a jaw operating cylinder 90 provided in the chuck C is actuated by a fluid supplied from a rear portion of the main spindle 2 to open and close gripping jaws 93. Thus, the gripping jaws 93 can be operated by means of the jaw operating cylinder 90 provided in the chuck C when the chuck C is mounted on the tip of the main spindle 2.

Abstract: A machine tool chuck in which a wedge member is provided to cause radial displacement of workpiece clamping pawls for replacement. The replacement can be made with minimum variations in radial position at which the clamping pawls are relocated. To this end, the clamping pawls and slide blocks are slidably guided radially through a chuck body independently of each other. Each clamping pawl and each slide block are in slidable engagement with a sloping wedge action portion of an axial slidable wedge bar in such a way that axial displacement of the wedge bar will force both the clamping pawl and the slide block to move radially independently of each other while maintaining the geometric relationship therebetween. For replacement of the clamping pawl, the wedge bar is moved backward to cause its wedge action portion to be disengaged from the clamping pawl whereby the clamping pawl can be slid radially outwardly for replacement.

Abstract: A chuck jaw changer for a machine tool has a jaw changing arm which is swingable about a vertical rotating shaft. The two ends of the arm have elongated magazine holders extending transversely to the length of the arm. The magazine holder has a guide groove in which an elongated jaw magazine is fitted slidably along the length of the holder. The magazine is formed with a plurality of jaw storage grooves spaced apart from each other and chuck jaws are detachably accommodated in the storage grooves, respectively. When the jaw changing arm is indexed to position the magazine holder into registry with the jaw mounting groove of the chuck, one of the jaw storage grooves of the magazine is brought into alignment with the jaw mounting groove so that a jaw changing device operates to shift the jaw between the storage groove and the jaw mounting groove for changing the jaw.

Abstract: A centrifugal force compensation device in a wedge-type balanced rotary chuck having jaws comprises, for each jaw, a balance weight and means for doubling the centrifugal force acting on the balance weight and applying the doubled force to the back face of that jaw near the outer periphery thereof thereby to press forward the jaw and impart thereto a moment urging it to rotate inward toward the chuck axis, whereby the so-called jaw flotation phenomenon is countered and prevented and, simultaneously, the reduction in chuck gripping force due to centrifugal force is compensated for.