Abstract: A tray (20) for holding contact lens mold assemblies (70) during thermal curing of a contact lens precursor material in an oven (210) to form contact lenses. The tray (20) comprises a plurality of plates (60) and a frame (25) supporting the plates (60). The frame (25) is configured to be stacked vertically with a plurality of identical frames to form a tray stack (10). Each plate (60) is a carbon-fiber reinforced polymer plate and comprises a plurality of support structures (110) each arranged to support one contact lens mold assembly (70) during curing and a plurality of channels (90, 100) connecting the support structures (110), to allow gases to flow between them in the tray stack (10) during curing.