FEC AFC1500 - Manual (Page 104)

Chapter 6: Fastening Instructions
Page 6-18
6.2.4 Point-to-Point Torque Rate Monitoring
The AFC1500 System is capable of performing 3 torque rate calculations. The Point-to-Point torque
rate method performs the calculation based upon completing a step of the process, and then calculat-
ing the rate for the full duration of that step. The chart below identifies the different areas that torque
rate can be calculated. Each Torque Rate is calculated by dividing the change in torque during the
specific period by the change in angle.
Example: 25Nm / 100deg. = 0.25 Nm/Deg. (rate)
NOTE: Setting any of the Torque Rate START POINTS above the FASTENING
END TORQUE will eliminate the torque rate calculation for that stage.
Torque Rate Calculation Areas (Typical for 1 or 2 step)
(CROSSOVER TORQUE set above FASTENING END TORQUE)
Refer to Fig. 6-2-4a
STAGE START POINT STOP POINT
1ST TORQUE RATE THRESHOLD TORQUE 1ST TORQUE
2ND TORQUE RATE 2ND RATE START TORQUE FASTENING END
Torque Rate Calculation Areas (Typical for 3 step, however can be used on 1 or 2 step)
Refer to Fig. 6-2-4b
STAGE START POINT STOP POINT
1ST TORQUE RATE THRESHOLD TORQUE 1ST TORQUE
2ND TORQUE RATE 2ND RATE START TORQUE CROSSOVER TORQUE
3RD TORQUE RATE CROSSOVER TORQUE FASTENING END
In the case that Torque Rate Stop Points are not set incrementally larger from THRESHOLD
to 2
ND RATE START TORQUE and then to CROSSOVER TORQUE, the rate calculation will
be performed at the next successive available stop point prior to Fastening end.
STAGE START POINT AVAILABLE STOP POINTS
1ST TORQUE RATE THRESHOLD 1ST TORQUE
CROSSOVER TORQUE
FASTENING END
2ND TORQUE RATE 2ND RATE START CROSSOVER TORQUE
FASTENING END
3RD TORQUE RATE CROSSOVER TORQUE FASTENING END
For all control operations, the High and Low Torque Rate limits are set by determining the
acceptable limits from a study of known good and bad assemblies.
NOTE: Refer to table above for stand alone SAN Unit Start/Stop points.