The Re-torque step is used to apply additional torque to a previously tightened joint to overcome any relaxation that occurs after the initial tightening (for example: a gasketed joint). The instruction is only used after the Torque Control or Angle Control instructions. It activates the tool's motor (in the tightening direction) and monitors the applied torque until a Re-Torque set point is reached.
For each tool activation, bolt angle rotation is measured from the time the torque rises to 50% of the Re-Torque set point until it falls back to 50% of the Re-Torque set point. The angle measured is added to the previous instruction's final peak angle. The peak angle is thus updated for each Re-Torque activation. Tool activations are continued until the angle measured during an activation is equal to or less than the user programmed Re-Torque Angle parameter or until 10 activations are completed. Total tightening angle is the Peak Angle from the previous tightening step + any angle turned during the Re-torque applications.
The Re-Torque Target Torque is equal to the previous Torque Control set point if the previous instruction was Torque Control or the Peak Torque obtained at the end of the tightening if the previous instruction was Angle Control.
There may be additional Torque overshoot during Re-Torque that was not present during the initial tightening instruction. This can be minimized by programming the Re-Torque Overshoot parameter. If programmed, the Re-Torque set point is set equal to the ReTorque set point - the Re-Torque Overshoot.
The previous instruction's Torque and Angle limits are also used for the Re-Torque instruction.
The Re-Torque specific programmed parameters are:
|Used to determine if the Re-Torque activations have supplied sufficient torque to the joint. The tool socket's angle of turn is measured from the time that a Re-Torque activation is started until it is turned off (Re-Torque Set Point is reached). This angle of turn gets shorter as each activation proceeds. When the angle of turn is equal to or less than the Re-Torque Angle the Re-Torque step is complete.
|A compensation parameter that adjusts for the average Torque Overshoot (caused by the motor's startup inertia) during a Re-Torque activation. The Overshoot value is subtracted from the Re-Torque Set Point to generate an adjusted Re-Torque Set Point. Programmed in the Advanced Step Settings.
|EOR Data Enabled
|When checked, the system will output an End of Run message at the completion of this Tightening strategy. Enabled in the Advanced Step Settings->Flags.