Patent ID: 7393490

Claim:
A molding method for molding a vehicular lamp part having an undercut portion that has a surface that slants with respect to a die closing/opening direction of a movable die, comprising: molding the vehicular lamp part in a molding apparatus comprising: a fixed die which closes together with the movable die to define a cavity; an extrusion plate positioned on a first side of the fixed die, with the movable die disposed therebetween, and which is movable in the die closing/opening direction; a separate push-up block, forming a portion of the cavity defined by the movable die corresponding to the undercut portion; a push-up pin comprising a first end fixed to the push-up block, a second end turnably held by the extrusion plate, and a middle part inserted into an insertion hole formed in the movable die; and the movable die comprising a gap formed between the insertion hole and the push-up pin that enables the push-up pin to tilt, releasing the vehicular lamp part from the movable die via the push-up block by relative movement between the extrusion plate and the movable die; and freeing the push-up block from the undercut portion by tilting the push-up pin with respect to the extrusion plate via further movement of the vehicular lamp part so that the slanted surface of the undercut portion pushes a die surface of the push-up block in a direction which intersects with the die closing/opening direction; the molding apparatus further comprises a positioning block, fixed to the second end of the push-up pin, comprising contact surfaces continuously extending at angles on the top and bottom thereof, wherein the push-up block is held in a die closed position by contact between a first surface, of the contact surfaces, and a restricting surface formed on the extrusion plate, and wherein, the push-up block is freed from the undercut portion via the movement of the first surface away from the restricting surface of the extrusion plate.