What's happening: During a particularly volatile market session, shares of ExOne (NASDAQ:XONE) have so far (as of 2:25 p.m. EDT) fallen as much as 10.4% and gained as much as 10.7%.

Why it's happening: There weren't any notable developments directly related to ExOne today. It appears that general market volatility has taken the industrial 3D printing company on an even wilder ride than the indexes.

Today's action is on the heels of ExOne's second-quarter earnings, which fell below analyst expectations by a wide margin. Along with the disappointing release, ExOne lowered its full-year gross margin expectations due to an unfavorable mix between its 3D printer and 3D printing services sales. The company, however, reiterated its full-year guidance of generating between $58 million and $66 million in revenue.

Considering ExOne has consistently struggled to meet its own and Wall Street earnings targets on a historical basis, investors may be resetting their own growth expectations today. Although it's been a frustrating experience for the ExOne faithful, days like today are valuable reminders that volatility is the price of admission to invest in an unproven small-cap growth company.

Steve Heller owns shares of ExOne. The Motley Fool recommends ExOne. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.