Detecting maintenance indicator of tightening tool

A computer program product stored on a non-transitory computer-readable medium, said computer program product for detecting that a tightening tool should be subjected to maintenance, wherein said computer program product comprising computer instructions to cause a processing unit to perform the following operations:

• acquiring data indicating a tightening trace comprising torque and rotation angle values applied to a fastener being tightened during a tightening operation performed by the tightening tool;
• determining whether a selected section of the tightening trace is linear;
• and if so:
• deriving, from the linear section of the tightening trace, at least one value indicating the applied torque and acquiring a value indicating current consumed by the tool upon applying the torque;
• computing a ratio between the at least one derived torque value and the value of the consumed current;
• comparing the computed ratio with a correspondingly computed reference ratio of a previously performed tightening operation;
• and
• if the comparing of the ratios indicates that the consumed current is increasing above a preconfigured current threshold value, determining that the tool should be subjected to maintenance.

A device configured to detect that a tightening tool should be subjected to maintenance, the device comprising a processing unit operative to cause the device to:

• acquire data indicating a tightening trace comprising torque and rotation angle values applied to a fastener being tightened during a tightening operation by the tightening tool;
• determine whether a selected section of the tightening trace is linear;
• and if so to;
• derive, from the linear section of the tightening trace, at least one value indicating the applied torque and acquiring a value indicating current consumed by the tool upon applying the torque;
• compute a ratio between the at least one derived torque value and the value of the consumed current;
• and
• compare the computed ratio with a correspondingly computed reference ratio of a previously performed tightening operation;
• and
• if the comparing of the ratios indicates that the consumed current is increasing above a preconfigured current threshold value, to determine that the tool should be subjected to maintenance.