NORWOOD, Ohio (AP) — Herbie Mays is 3M proud, and it shows — in the 3M shirt he wears; in the 3M ring he earned after three decades at the company's plant in suburban Cincinnati; in the way he shows off a card from a 3M supervisor, praising Mays as "a GREAT employee." Bent on cutting costs and refocusing its portfolio, the company decided to close the plant that made bandages, knee braces and other health care supplies and move work to its plant in Mexico. In the state-of-the-art laboratory in a World War II-era building the size of 27 football fields, workers use breakthrough technology to build jet engines that run on less fuel at higher temperatures. Donald Trump won the presidency in great measure because he pledged to stop American jobs and manufacturing from going overseas, winning Rust Belt votes from Mays and other blue-collar voters. More and more factory jobs now demand education, technical know-how or specialized skills. Last year, software developer was the second-most-common job advertised by manufacturing companies, behind only sales, according to data provided by Burning Glass Technologies, a company that analyzes labor market data. [...] Sen.