(section: 3 / paragraph: a / line: 1)
Per General Rule 1, yes it is allowed. As long as it complies to all other event rules, general rules, and the official Science Olympiad Building and Tools policy found at http://soinc.org/building_tools_policy. A 3D printer is no different from any other workshop tool such as a table saw or drill press.
(section: 3b / line: 1-2)
No, a buret is not a commercial counter and is legal for competition.