3-D printer maker 3D Systems (DDD -0.86%) dropped 11% yesterday after the company's management team announced a secondary offering of nearly 6 million shares. This will lower the value of all existing shares, which is why shareholders were not pleased.

So why would 3D Systems do this? According to Motley Fool analyst Sara Hov, the offering will give 3D Systems around $317 million in additional capital to fund its massive expansion efforts. Sara thinks this is a good move for the company, since it is getting overwhelmed with its backlog right now -- but expansion will allow 3D Systems to keep up.

So, is today the day for investors to dive into 3D Systems? On today's "Stock of the Day", Sara says yes -- in fact, she's already a 3D Systems shareholder. The stock is down from the highs it hit at the beginning of the year, so this may present a great buying opportunity.