(Image source: core77.com) Shares of the 3-D printer maker ExOne Co (NASDAQ:XONE) are taking a nosedive this morning after the company cut its 2013 revenue outlook. The company now expects to report full year revenue for 2013 at a range of $40 million to $42 million, down from the previous estimate of $48 million. The cut in revenue guidance was a result of international customers deferring purchases into 2014. The news from ExOne is dragging down the rest of industry; all the major 3-D printing stocks are negative.