A 3D printer and method for increasing the speed of 3D printing, wherein said 3D printer comprises a heating block, a nozzle (1) attached to the heating block, and a hole through the heating block and the centre of the nozzle (1). In said hole there is a heat conductive material (7) attached in at least one place on the inner side wall of the hole for transferring heat (5) from the side wall towards the centre of the hole.