Rexroth Tightening System 350 System Documentation - Rhino ...

9 Tightening Processes Tightening Technology | Bosch Rexroth AG 225/3169.2 Tightening program stepsThe Find (1) tightening step (Fig. 9–31) is used to position the bolt in the bore and is torque-controlled(target function Torque). It is ended when the target function is reached.The Tightening (screwing in) process (2) is programmed as an extended tightening step with monitoringfunctions Tightening, upper and Tightening, lower. It is torque-controlled (target function Upper torque)and the monitoring functions Tightening, upper and Tightening, lower are active. The tightening step isended when the target function is reached. The tightening step is evaluated as NOK if the tolerance limitshave been violated ((T > TCh+) and/or (T < TCl–)), and otherwise as OK.In contrast to the standard tightening step, the tightening evaluation is done retroactively once the targetfunction has been reached (in the example T J ). The reason for this is that the measurement values recordedfor the step are still in the SE graph memory at this point. Once the target function has been reached(T J ) the system checks that:– during the Ru flashback, torque T does not exceed the upper tolerance limit TCh+ within Mu (in theexample: flashback by 1300°, TM < 17.5 Nm within 900°)– during the Rl flashback, torque T does not fall below the lower tolerance limit TCl– within Ml (in theexample: flashback by 800°, TM > 14 Nm within 750°).If the torque T reaches the hatched area within the upper monitoring angle Mu or the lowering monitoringangle Ml (exceeding or falling below the tolerance limits TCh+ or TCl–, see Fig. 9–31), the tightening processwill be evaluated as NOK. Causes for violating the upper tolerance limit TCh could include too-smallbolt holes or bolt hole tolerances and too-large holes or tolerances if the lower tolerance limit TCl is violated.If the monitoring area determined by the flashback angle and monitoring angle is only partially available inthe tightening controller graph memory, only this part will be evaluated. The tightening monitoring is evaluatedas OK if the torque is within the set tolerance limits. The tightening monitoring will be evaluated asNOK if the monitoring area is completely outside the data in the graph memory (QC: TCh+, TCl–). Noactual value will be output.NoteThere are always 2000 points available for tightening monitoring (screwing-in phase), independent of thenumber of measuring points set in the start step for the graph.The tightening process is paused to evaluate the tightening monitoring for the screwing-in phase and thenutrunner tension is relieved to a defined point.A reverse spin direction may not occur in the monitoring area.Tightening averagingTightening averaging is an extension of tightening monitoring for the screwing-in phase. In addition to thetightening torque, flashback angle, and monitoring angle, a measurement value quantity n can be enteredthat is used to average the torque measurement values in the tightening controller graph memory(Fig. 9–33). This setting smoothes out the torque course within the monitoring angle before it is evaluated.Figure 9–33:Continuation of Fig. 9–32: Example parameterization for Tightening, upper/lowerSystem 350 | 3 608 878 040/05.2008