What are the objectives of assembly line balancing?

(industrial engineering) Assigning numbers of operators or machines to each operation of an assembly line so as to meet the required production rate with a minimum of idle time.

http://www.answers.com/topic/assembly-line-balancing

http://www.prenhall.com/weiss_dswin/html/balance.htm

http://online.uis.edu/spring2000/bus322/lectures/chap09/sld063.htm