Are there any 3D printing services or something similar to 3D print or injection mold light reflectors?
I'm trying to find something that is similar to PCB printing that allows you to upload a 3D design of a reflector and they will produce this reflector and coat it with mirror surface.
You can make flat reflectors with glass panels or acrylic panels and apply window mirror film. Ordinary window glass might be less expensive than acrylic and many places will cut to size, but unusual shapes might not be an option. The mirror film is relatively easy to apply and the packages have instructions included.
For the hologram pyramid you referenced, one could 3d print the bracket at the base. If your design is different, yet similar, that's an option for relatively easy construction.
100-200 pieces is really too small of a quantity to justify expensive injection molding. If the part is not too complex, one could create the model with 3d printing, then build a silicone mold around it, followed by pouring polyester or epoxy casting resin to make larger quantities. A better idea of the shape would be useful, but the information I've provided may head you in a practical direction.
I would not recommend extrusion printers for this, because they are unlikely to produce a smooth enough surface. To get a clean surface, the irregularities have to be a fraction of visible wavelengths, which is to say on the order of 0.01 micron.
Without knowing what sort of reflector you're thinking of (flat? spherical? parabolic?), it's hard to recommend a specific optimal, cheap approach. All in all, you're probably best off looking in standard catalogs such as Edmund Optics.
