Proto Labs Inc. is buying select assets of German manufacturer Alphaform AG, in a move that greatly extends its prototyping reach into Germany, Finland and the United Kingdom.

Terms were not disclosed. The deal is expected to close next month.

With the purchase, Maple Plain-based Proto Labs gains additional manufacturing might across Europe, which now accounts for about 20 percent of the company’s $200 million in revenue.

Alphaform, based near Munich, provides metal molding, laser sintering and 3-D printing operations for customers at factories in Germany, Finland and England. Alphaform also owns medical product subsidiaries MediMet Precision Casting and Implants Technology GmbH, but it is not included in the Proto Labs transaction.

Proto Labs CEO Vicki Holt said in a statement that Alphaform’s division will increase the prototyping and custom manufacturing services Proto Labs can offer customers abroad. “This strategic acquisition [will] accelerate the growth of our additive manufacturing services in Europe and complement our current injection molding and CNC machining services,” she said.

Proto Labs first entered the 3-D printing or additive manufacturing market in April 2014 when it bought FineLine Prototyping in Raleigh, N.C., for $37 million.

By adding parts of Alphaform AG, Proto Lab accelerates that reach into 3-D printing and cements part of an aggressive growth strategy that envisions reaching $1 billion in annual revenue.

Proto Labs is spending $25 million to expand its recently purchased 3-D printing plant in North Carolina.

Investors welcomed Thursday’s news. Proto Labs stock rose 2.2 percent, or $1.50 a share, to close at $69.82.