A method of making a part with regions of different thickness from a plate workpiece having a pair of substantially parallel plate faces. The workpiece is fitted between a surface of a die and a substantially parallel surface of a punch. The die is formed at its surface with an opening. Then the die and the punch are relatively shifted parallel to the surfaces and faces and so as to compress the workpiece parallel to its faces to extrude the workpiece transversely into the opening in the die surface, thereby creating a region of greater thickness.
A drawing method for forming a reflective curved surface by pressing a metal plate fitted in a fixed die with a movable die. The fixed die is composed of a lower die and a core, and the movable die is composed of an upper die and a presser. During the drawing, the metal plate is pressed to have a compressed border portion between a non-pressed portion and a curved surface pressed portion. It is the most desirable to compress the border portion to have a thickness which is 70% of the thickness of the metal plate before drawing.
