For the first two centuries of American history, the weaving of cloth was a cottage industry, even after the introduction of power spinning frames in 1790. Yarn produced by machines in water-powered factories was still put out for weaving on hand looms in homes. All cloths were woven in basically the same way, although weavers followed patterns to produce cloths with intricate weaves. Because the operations of a loom focus on such a small working area, its movements must be exact. And weaving, as opposed to spinning, requires a cycle of sequential steps and involves reciprocal movement as well as circular. In a power loom, movements coordinated by human hand and eye have to be replicated through the precise interaction of levers, cams, gears, and springs. For these reasons, weaving was the last step in textile production to be mechanized.
Successful power looms were in operation in England by the early 1800s, but those made in America were inadequate. Francis Cabot Lowell realized that for the United States to develop a practical power loom, it would have to borrow British technology. While visiting English textile mills, he memorized the workings of their power looms. Upon his return, he recruited master mechanic Paul Moody to help him recreate and develop what he had seen. They succeeded in adapting the British design, and the machine shop established at the Waltham mills by Lowell and Moody continued to make improvements in the loom. With the introduction of a dependable power loom, weaving could keep up with spinning, and the American textile industry was underway.
Source: Lowell National Historical Park Handbook 140