The disclosure provides for a process for manufacturing a tread molding element configured to mold at least a portion of a tire tread, the process comprising the following successive steps of providing a first tread molding element that can be a 3D-printed element made of a plastic composition A; forming a reverse mold of the first tread molding element, wherein the reverse mold is made of a plastic composition B comprising one or more elastomers; heating the reverse mold to a temperature above 50 C. when the first tread molding element is a 3D-printed element made of a plastic composition A; and casting a second tread molding element from the reverse mold to obtain a second tread molding element; wherein the second tread molding element is made from a plastic composition C comprising one or more thermosetting resins.