(Adds details, updates share movement)
May 14 (Reuters) - ExOne Co reported quarterly revenue much below analysts' expectations as the company sold fewer 3D printers and micromachinery.
The company's shares fell 18 percent in extended trading.
ExOne said gross margin dropped to 22.2 percent in the first quarter ended March 31 from 35.8 percent a year earlier due to "significant development costs" for its ExCast casting technologies.
The company said on Wednesday it now expects 2014 gross margin of 40-43 percent, down from its previous forecast of 43-46 percent.
ExOne's machines, which cost anything between $100,000 and $1.5 million, can print on diverse materials such as stainless steel, bronze, glass, silica sand and ceramics.
Larger rival 3D Systems Corp last month reported its first drop in quarterly gross margins in two years.
First-quarter net loss attributable to ExOne widened to $5.5 million, or 38 cents per share, from $1.9 million, or 20 cents per share, a year earlier.
Excluding items, the company reported a loss of 37 cents per share, way above analysts' average estimate of a loss of 12 cents, according to Thomson Reuters I/B/E/S.
Revenue fell to $7.3 million from $7.9 million a year earlier. Analysts had expected revenue of $9.9 million.
Printers and other machinery sales - a third of total revenue - almost halved to $2.4 million from $4.2 million. Sales of Printing parts and materials brought in $7.3 million.
ExOne also makes micromachines which use laser to drill high-precision holes.
The company's shares, which have lost almost half their value so far this year, closed at $30.83 on the Nasdaq on Wednesday. (Reporting by Sruthi Ramakrishnan in Bangalore; Editing by Joyjeet Das)