Error in schedulinq parallel sequences with flow production operations

Question

We have a routing with a standard sequence with operations in wich we have set "Continuous flow prod"
and "Min. Send-Ahead Qty=1".
We have a parallel sequence as well with operations set in the same way "Continuous flow prod"
and "Min. Send-Ahead Qty=1".
When you run the transaction "MD11" to create a planned order for the item the scheduling of the operations is correct
as regard the standard sequence,the system, correctly,  schedules the operations overlapping
them according to lead time set in the operation details.
But the last operation of the parallel sequence is scheduled to finish the whole lot before the operation
following the "return operation" . The system doesn't overlap this operation. In this way the
last item of the last operation (in the parallel sequence) isn't finished at the same time
with the last item of the "return operation" (in the standard sequence) as we like it would be.
We have set "Backwards scheduling" type on customizing and we use the "Alignment key= 2 "
for standard sequence and in the parallel as well. We have also tryed to set "Alignment key= 1"
in the parallel sequence but the results are howewer not correct.
In conclusion the schedulation of  continuous flow production operations
doesn't work properly between operations belonging to parallel sequences.
Could you suggest me what to do?
Thank you.

Answer 1

Hi,
  I tried with 5 ops 10, 20, 30 ,40,50 ( same work center  wc1)
  Set up time 1, Process time 1min for 1 pc
  set the continuous flow prodn i at op 20 with min send ahead qty 1
  Also a parallel seq was created with 3 ops op20 ,30 , 40 .
  set up time was 2 min for all work centers( same work center wc2) and proc time
  time is 1 min for  1 pc
  In that set the  continuous flow prodn at op 20 with min send ahead qty 1
  sceduling type was forward
.Alignment key was 2 for both std seq and parallel seq .
  After scheduling found that op 20 in std seq starts at 6.14am and op 40 ends
  at 6.47 am where as in parallel seq op 20 starts at 6.11 am and op 40 ends at
  at 6.47 am which is correct.( branch op is 20 and return op is  40)
  The three minutes late start in op 20 of std seq  is due to 3 minutes extra time
  defined for three  work centers setup time.
  I also tried with alignment key 1in both std seq and parellel seq.
Kindly check that you have maintained the continous flow prodn radio button
in the same operation in both std seq and parallel seq.
Regards,
S.Nandhakumar