Chuck Kummeth spent more than two decades working for Maplewood-based 3M Corp., serving as vice president of the company’s medical division from 2006 to 2008. In 2013 he took the top spot at Minneapolis-based Techne Corp., renamed Bio-Techne in 2014. Since Kummeth took the helm, the biotechnology company has been on a buying spree, with six notable acquisitions. The numbers tell the story: For fiscal 2015 (ending in June), Bio-Techne reported sales of $452.2 million, up more than 68 percent from two years earlier.