Abstract: Provided is a technique capable of suitably determining screw fastening failure. A screw fastening failure determination device (10) includes: a speed acquisition unit (13) which acquires an axial speed of a screw driver or a speed feature value relating to the speed; and a failure determination unit (14) which determines, in a temporary seating process, that a screw fastening has failed on the basis of the axial speed or the speed feature value at a prescribed timing.

Abstract: Even when a tapping screw is used in a soft material, it is determined whether or not a screw tightening defect has occurred. A PLC (10) comprises a determination unit (13) which for a rotational torque data sequence having a predetermined number of data points, generates a normalized torque data sequence that is the amount of change with respect to rotational torque at a first data point of the data sequence, and determines whether screw tightening is defective, on the basis of the normalized torque data sequence.

Abstract: A screw length determination system capable of quickly determining the length of a screw is obtained. A PLC (10) is equipped with a determination part for measuring the moving speed of a driver for tightening screws in the axial direction of the driver from an initial position until a screw contacts and is screwed into a workpiece, and determining the length of the screw on the basis of the time from the start of movement from the initial position until the moving speed changes.

Abstract: Provided is a screw length determination system capable of determining the length of a screw with a high degree of accuracy. A PLC (10) determines the length of a screw on the basis of the amount of rotation or the position in the axial direction of a driver during a period lasting from the time when the screw completes its descent until any time from among the time when provisional seating occurs, the time when the primary tightening period ends and the time when the period of holding for primary tightening ends.

Abstract: Provided is a technique capable of suitably determining screw fastening failure. A screw fastening failure determination device (10) includes: a speed acquisition unit (13) which acquires an axial speed of a screw driver or a speed feature value relating to the speed; and a failure determination unit (14) which determines, in a temporary seating process, that a screw fastening has failed on the basis of the axial speed or the speed feature value at a prescribed timing.

Abstract: The present invention provides technology with which it is possible to highly accurately assess the quality of fastening of a screw. The present invention comprises a position acquisition unit (13) that acquires the axial-direction position of a driver (50), and a fault assessment unit (14) that assesses that a fault has occurred in fastening of a screw when the amount of change in the axial-direction position of the driver (50) from when temporary seating occurred is greater than a threshold value. The present invention provides a technology with which the quality of screw fastening can be assessed with high precision.

Abstract: Provided is a screw length determination system capable of determining the length of a screw with a high degree of accuracy. A PLC (10) determines the length of a screw on the basis of the amount of rotation or the position in the axial direction of a driver during a period lasting from the time when the screw completes its descent until any time from among the time when provisional seating occurs, the time when the primary tightening period ends and the time when the period of holding for primary tightening ends.

Abstract: A screw length determination system capable of quickly determining the length of a screw is obtained. A PLC (10) is equipped with a determination part for measuring the moving speed of a driver for tightening screws in the axial direction of the driver from an initial position until a screw contacts and is screwed into a workpiece, and determining the length of the screw on the basis of the time from the start of movement from the initial position until the moving speed changes.