3D printing is an additive manufacturing process. There are many different types of 3D printers. Tools are created using a "Fused Deposition Modeling" (FDM or FFF) commercially available, consumer desktop 3D printer. An FDM printer heats thermoplastic to its melting point, extrudes it through a nozzle, and deposits it on a plate layer-by-layer, fusing one on top of another to form a 3D object from the bottom, up.
FDM printed objects have an inherent quality that differs from other types of manufacturing like injection molding, laser cutting, die cutting, and other 3D printing additive manufacturing techniques. Since FDM objects are created layer by layer, they have visible layer and pattern lines based on how the molten plastic is fused with the previous layer.
The visible layer and pattern lines created by the FDM process gives the stencils a unique appearance that differs from commercially manufactured products.
Q:
Who prints your 3D printed items?
A:
We do, on our own desktop 3D printers.
Q:
What plastic do you use for your 3D printed items?
The stencils are printed in-house using commercially available consumer desktop 3D printers, so they're not guaranteed to be dimensionally accurate in shape or in size. If you use them for art, they're great. If you need a stencil that's accurate to a standard (e.g., within a tolerance of .001") because you're creating exacting technical drawings, my stencils probably aren't for you. And that's okay.