A control apparatus of a machine tool includes: a slide position control unit configured to control a slide according to operation patterns; a pressure command generation unit configured to generate a pressure command for a die cushion according to the operation patterns; a pressure detection unit configured to detect an actual pressure of the die cushion; a die cushion speed control unit configured to control the die cushion, based on an error between the pressure command and the actual pressure; and a command reach determination unit configured to determine whether or not the error is greater than a pressure threshold, wherein the slide position control unit sets, based on a result of the determination by the command reach determination unit, a waiting period between the operation pattern at the time of the determination and the next operation pattern, wherein the slide is kept at its position during the waiting period.

A die cushion device of a press machine includes a hydraulic cylinder that supports a cushion pad and generates die cushion force when a slide of the press machine descends, an orifice and a hydraulic pump/motor that are connected to each other in in parallel between a lower chamber of the hydraulic cylinder and a tank, a servo motor connected to a rotating shaft of the hydraulic pump/motor, and a control unit that controls torque of the servo motor to control the die cushion force, wherein a rotation direction of the servo motor switches from a first rotation direction in which the hydraulic pump/motor serves as a hydraulic motor to a second rotation direction in which the hydraulic pump/motor serves as a hydraulic pump, during generation of the die cushion force.

A die cushion device of a press machine includes a hydraulic cylinder that supports a cushion pad and generates die cushion force when a slide of the press machine descends, an orifice and a hydraulic pump/motor that are connected to each other in in parallel between a lower chamber of the hydraulic cylinder and a tank, a servo motor connected to a rotating shaft of the hydraulic pump/motor, and a control unit that controls torque of the servo motor to control the die cushion force, wherein a rotation direction of the servo motor switches from a first rotation direction in which the hydraulic pump/motor serves as a hydraulic motor to a second rotation direction in which the hydraulic pump/motor serves as a hydraulic pump, during generation of the die cushion force.

Provided is a press-forming apparatus including: a punch; a die having an inclined surface inclined toward a hollow part into which the punch is inserted and; a die plate holding the die; a blank holder having a holding surface facing the inclined surface of the die; a die load sensor detecting a load in a pressing direction, a load in a first direction perpendicular to the pressing direction, and a load in a second direction perpendicular to the first direction; a controller that calculates a normal force of the die based on the loads in the pressing direction, in the first direction, and in the second direction, the loads being detected by the die load sensor, and calculates the amount of correction of clearance between the die and the blank holder based on the normal force of the die; a first driver that moves the die in the pressing direction based on the amount of correction of clearance; and a second driver that drives the punch in the pressing direction.

Provided is a press-forming apparatus including: a punch; a die having an inclined surface inclined toward a hollow part into which the punch is inserted and; a die plate holding the die; a blank holder having a holding surface facing the inclined surface of the die; a die load sensor detecting a load in a pressing direction, a load in a first direction perpendicular to the pressing direction, and a load in a second direction perpendicular to the first direction; a controller that calculates a normal force of the die based on the loads in the pressing direction, in the first direction, and in the second direction, the loads being detected by the die load sensor, and calculates the amount of correction of clearance between the die and the blank holder based on the normal force of the die; a first driver that moves the die in the pressing direction based on the amount of correction of clearance; and a second driver that drives the punch in the pressing direction.

A method for producing a complex sheet metal part includes clamping a border region of the metal sheet between a die ring of an upper tool part of a pressing tool and a downholder of a lower tool part of the pressing tool; moving the upper tool part further downwards thereby pulling the metal sheet over extended punch inserts of a punch of the lower tool part, thereby generating local material reserves of the metal sheet; moving the upper tool part further downwards while actively retracting the punch inserts, thereby releasing the local material reserves; and forming the metal sheet between the die and the punch using only the local material reserves.

A deep-drawing tool for deep drawing blanks which are punched out of sheet material that is painted or coated with film material, in order to obtain flangeless molded blanks, includes a drawing bell, a drawing core, a blank holder, a force transmission device, a drawing cushion for applying a spring force to the blank holder by the force transmission device, and a drive which, after the drawing bell reaches a predetermined position in downward movement thereof, drives the force transmission device to perform a movement which precedes movement of the drawing bell.

A method of manufacturing a press-formed product includes: capturing the amount of warp in a sheet to be pressed separately for each sheet; and using a die 6, a punch 7, and a movable mold part to press-form the sheet into a press-formed product. During press-forming, the initial position of the movable mold part 9 relative to the die 6 or punch 7 is controlled depending on the amount of warp in the sheet.

A method of manufacturing a press-formed product includes: capturing the amount of warp in a sheet to be pressed separately for each sheet; and using a die 6, a punch 7, and a movable mold part to press-form the sheet into a press-formed product. During press-forming, the initial position of the movable mold part 9 relative to the die 6 or punch 7 is controlled depending on the amount of warp in the sheet.

A double-blank detecting apparatus for a press machine that is provided with a die cushion apparatus and is configured to form blanks one by one automatically and repeatedly. The double-blank detecting apparatus includes: a position signal acquiring unit configured to acquire a slide position signal indicating a position of a slide of the press machine; a load signal acquiring unit configured to acquire a die cushion load signal indicating a die cushion load generated on a cushion pad of the die cushion apparatus; and a double-blank detector configured to detect a state in which a plurality of blanks are stacked as a double blank based on the slide position signal acquired by the position signal acquiring unit and the die cushion load signal acquired by the load signal acquiring unit.