3D printers are a general term for additive manufacturing technologies that create three-dimensional objects by layering materials based on digital data. Their greatest feature is the ability to directly manufacture shapes with complex internal structures and free-form surfaces, which are difficult to achieve with traditional methods like cutting, without the need for molds. Their applications range from functional prototyping and design verification in product development, to on-demand production of jigs, fixtures, and spare parts, and even to the manufacturing of final products in aerospace and medical fields. Representative manufacturing methods include Fused Deposition Modeling (FDM), Stereolithography (SLA), and Selective Laser Sintering (SLS), and the materials used vary widely from resins to metals and ceramics. As a result, they are attracting attention as a core technology that shortens manufacturing lead times, reduces costs, dramatically improves design freedom, and accelerates the digital transformation (DX) of the manufacturing industry.