The IPO priced at $18 each, the high end of its $16 to $18 range.
The underwriters have a 30-day option to buy up to an additional 483,333 shares from ExOne Co. and 311,667 shares from Rockwell Holdings to cover any excess demand.
Shares rose $8.25 to $26.25. The shares opened at $23.66 on Thursday.
The stock is trading on the Nasdaq under the "XONE" ticker symbol.