SWAMPSCOTT – Mark Gelfand?s generosity continues to be felt around town, most recently with the 3D printer the library purchased with a donation from the software developer and Swampscott resident.The library acquired the black, box-shaped machine roughly the size of a small television after Gelfand attended a recent local robotics innovation demonstration and made a donation to pay for similar programs.?I immediately said I wanted a 3D printer. The first time I heard about it, I thought it was science fiction,” said young adult librarian Sandy Moltz.Three-dimensional printing uses a glue-like substance and high technology electronics to create objects as simple as a nut and bolt and as advanced as a prosthetic arm. Moltz said the library?s MakerBot Replicator 5 printer is already exciting teenagers. She is planning a March library open house to introduce the printer, and she plans by April to help local teens with programs involving the printer.?We are aiming initially at getting teens participating as a group on projects using the printer,” said library director Alyce Deveau.Gelfand?s generosity to the town covers several years, with the Gelfand Family Charitable Trust in 2011 announcing plans to donate $1 million to Swampscott schools over a four-year period to pay salaries for three science, technology, engineering and mathematics (STEM) teachers.Gelfand advocates attracting students to biomedicine and bioengineering by starting clubs in schools devoted to those disciplines.Moltz said local teenagers are already drawing up plans for creating objects on the Replicator. She said the machine takes a half-hour or longer to create an object based on design information plugged into the printer.?You send it engineering specifications – dimensions – and it will make something,” she said.Deveau knows the printer is going to attract adult interest and said library employees will plan library free time when patrons of all ages can use the device.