3D printing holds promise for students with blindness/visual impairments (B/VI) in addressing astronomy content, concept development, and providing access to information normally displayed visually. To help bolster astronomy and STEM opportunities for students with B/VI, we developed the STEM Career Exploration Lab (CEL), which employs tactile astronomy instruction via 3D printing and specially designed 3D-printed models. Our unique project centerpiece is the 3D printer build, where students with B/VI assemble and use desktop 3D printers. By the end of 2024, we will have held 18 week-long STEM CEL summer camps in 12 states, 3 in each of the 4 main US census regions. We collaborated with Teachers of the Visually Impaired and general education STEM teachers via annual Educator Partner Institutes (EPIs) to develop our astronomy lessons and 3D models. These educators also assist with the STEM CEL summer camps. Thirty-three teachers from 11 states have participated. We gathered pre- and post-intervention data via surveys, astronomy assessments, and interviews, resulting in what is likely the largest research study on astronomy and 3D printing instruction for students with B/VI. Once fully evaluated and refined, we will make our 3D models and lessons freely available. We find that with appropriate context and guidance, 3D printing is effective in increasing scientific understanding and showcasing scientific data (largely from space telescopes) for appreciation of astronomy and STEM.