When Mexico set up the first maquiladoras half a century ago, they were sweatshops that simply bolted or stitched together imported parts, then exported the assembled product north across the border to the United States. America got cheap goods; Mexico got jobs and export revenues. Now, with competition growing from other low-cost locations, and with the government cutting some of their tax breaks, the maquiladoras are having to step up their efforts to become innovative.