Proto Labs Inc. will invest $25 million to expand the 3-D printing operation in North Carolina that it purchased a year ago, officials said Friday.

The investment, which will add 170 jobs in North Carolina over five years, involves the buying and renovating of an existing building and includes the upgrading of production equipment.

Proto Labs’ 3-D printing division will move into the new space in about six to nine months from two smaller leased locations in Raleigh, N.C., officials said.

The addition is the latest in a series of expansions for Minnesota’s Proto Labs, which is better known for quick-turn injection-molding and precision milling work.

Proto Labs bought the small 3-D printing firm, FineLine Prototyping in Raleigh, for $37 million in April 2014. That deal got Proto Labs into 3-D printing for the first time and gave it 85 workers on the East Coast.

At the time, Proto Labs CEO Vicki Holt said FineLine would not move to Minnesota and that Proto Labs would look for opportunities to grow that business.

On Friday, CFO John Way noted that the 3-D printing entity has done just that. “Our [3-D printing] additive manufacturing business grew 79 percent from the first quarter of 2014 to 2015. It’s been growing really well since we acquired it.”

FineLine custom manufactures three-dimensional parts for customers in the aerospace, medical, industrial and consumer product industries.

Going forward, the new North Carolina plant will help Proto Labs reach more 3-D printing customers quickly, said Proto Labs spokeswoman Sarah Ekenberg.

The expansion will help Proto Labs increase “the 3-D services that we currently have. It is our fastest-growing business. There is a lot of room for growth, given that it was our smallest [division].” she said.

On an annualized basis, 3-D printing contributed about $18 million to ProtoLabs’ $210 million in revenue last year.

The company is growing in other areas besides 3-D printing. Last year, Proto Labs opened a $19 million factory in Plymouth. That factory, which specializes in injection molding and lathe milling manufacturing, already transferred 175 workers to that site from the Maple Plain headquarters. Officials will add an additional 100 workers in Plymouth by 2017.

Separately, Proto Labs spent $3 million on equipment last year that allowed it to enter into two new product lines. It expanded beyond its mainstay of plastic injection molding and into steel and rubber injection-molding for the first time.

The expanded product line has accelerated growth, Way said.

The company reported first-quarter net income of $10.5 million for the three months ended March 31, up from $10.1 million for the same period a year ago. Revenue for the period was $58.5 million, up from $46.1 million.

In April, the company reported that the number of product developers and engineers who use Proto Labs services grew 44 percent in the first quarter. The company reported a record 11,000 unique developers and engineers had used its products and prototypes.

Proto Labs stock rose 46 cents to close at $68.24 a share Friday.