Use of flexible pads to print on uneven surfaces. Typically, an inked image is transferred from a photo-etched plate to a thick, soft silicone pad. The pad is then pressed against the plastic part. The pad can wrap itself as much as 180° around a small object, and ink coverage is excellent. One colour is done at a time, but registration between colours is good enough to allow four-color process printing. Recommended by some for direct printing of electronic circuits onto finished products.
See the IDTechEx report Introduction to Printed Electronics