Unfortunately the right frame of my beloved Urbanears Plattan Adv Wireless broke and UE wouldn't send me a spare one, so I designed one myself.
Works like a charm ♥
Slicing with Cura:
Extrusion width = 0.5 mm (with a 0.4-mm-nozzle)
Initial layer thickness = 0.3 mm
Sand it down a bit and make sure it fits snuggly into hinge part of the headphones.
Then hold the size ajustment section into the steam of an electric kettle to soften the plastic and form it in to a roundish form, so it resembles the original part. This is important to improve fitting and overall wearability!