Hello,
Ok, so is queue in front of or behind the work center?
Did not get your question.. its a gap between 2 operations we are talking about. As per the note there is a way to control this gap... refer section 6 solution which says....
The only way of avoiding the gaps is to incorporate maximum intervals to the relationships between the activities. When the maximum interval is zero, activity B follows directly on activity A.
Note
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Maximum intervals in the relationships must be used with caution. If both activities are finite, serious scheduling problems can occur. For more detailed information, see section 9.
Expert DB49 has already shown you where to maintain these values...
Regards
Abhishek