Most toothbrushes has multi color, following we are talking something about the double color toothbrush mould. We also call it bi-color toothbrush mould. Double color toothbrush mould has several mould structure according to different injection molding machine.
Insert moving, after machine molding the first material of toothbrush, the mold insert will go up or down by mould mechanical device or hydro cylinder. Then machine inject the second material. See following picture:
Insert rotating, mould core side have a bar connect with machine, when the first PP injection finished, the machine will rotating the core with toothbrush, and then make second injection, the mould base will be fixed without moving.
Last type is rotating the whole core side, this kind of mould is for normal double color injection molding machine.