A nonlinear optimization technique is applied for an efficient design of a six-bar linkage type beat-up mechanism for wide looms. The design problem is defined as a function generator design problem. Especially, the desired beat-up curve is defined to have a dwell period and errors between the desired and generated beat-up curves are minimized. Also design constraints are incorporated for practical application. As a result, a great number of satisfactory solutions for both Watt-II type and Stephenson-III six-bar linkages are found.