At this time , however , no crimp force monitor analyzes the area under the crimp curve as described in the LV . Similarly , the force curve data in the roll-in area is typically ignored during monitoring with filters . Therefore , the different area regions , X0 and X1 are theoretical and will only be considered during initial validation of the terminal .
Today ’ s crimp force monitors detect area differences as a result of crimp defects but analysis does not go to this detail . But the LV is not a specification on crimp monitors ; it is a specification on terminal characteristics . Regardless of how the area results are calculated , when crimped , the LV mandates that a terminal must exhibit significant differences in these areas so that a crimp force monitor can accurately detect all scenarios . If not , it will not be approved for use in an automotive harness . Furthermore , typical crimp monitors are used on the production floor . Therefore , if the terminal is already on the production floor , it has already been approved so this level of detail in the analysis is not required .
Feasibility Study
The feasibility study is the testing methodology for terminals as defined under LV 214-4 . It is to verify that defect modes can be detected for a terminal / wire combination . The output identifies the separation between good crimps and defect crimps . Tests must be performed using the smallest wire allowed for that terminal . For example , if the terminal is rated for 18 -22 AWG wire , 22 AWG wire should be used for testing . Although the procedure is written for initial validation of terminals , this process can be used on the production floor to determine the feasibility of any application .
After the application is set up , crimp parameters have been verified , and the teach crimps are completed , 300 good crimps and five empty crimps are processed . The relative deviation of the good crimp peak forces is calculated . The LV specifies a maximum relative deviation of 1 %. If the relative deviation is greater than 1 %, the terminal fails for this criteria and the testing stops . If the relative deviation is less than 1 %, the terminal passes and the test continues .
The next step is to test crimps with strands missing . The LV states that 9 % missing strands must be detectable . Examples are given for calculating the 9 % and rounding up for various wire sizes . For example , in a 7 strand wire , 9 % missing strands equals 0.63 , which round up to one missing strand that must be detected . For a 32 strand wire , a defect must be detected with three strands missing . 9 % of 32 equals 2.88 , which rounds up to three .
Ten crimp samples are processed with the required number of missing strands and all must be detected as defects . If not all are detected as defects , the terminal fails and the test stops . If all ten are detected as defects , the test proceeds .
The next step is to detect insulation in the crimp . Like with missing strand detection , 10 wires must be processed with insulation in the crimp area and all must be detect as defects . LV 214-4 mandates 30 % insulation inside the crimp for these tests and provides a clear method of measurement . If all are not detected as defects , the terminal fails and the test stops . If all are detected successfully , the test continues .
At this point , the operator considers the headroom . LV 214-4 states that headroom should
11 WN DECEMBER 2016