Forming of complex shapes in aluminum and magnesium alloy workpieces
A billet of an aluminum alloy or magnesium alloy is formed by a combination of forming operations into a desired article of complex, but open shape. In a first step a billet is heated and extruded to form an extruded workpiece profile having at least first and second sections of different thicknesses. The extruded workpiece may be shaped so that the respective sections are at an angle to each other. The extruded workpiece is then further formed against a forming surface so that the shape of least one of the sections is further formed toward the shape of the article. The methods are suitable for efficient manufacture of many like complex shapes such as brackets and reinforcement members, and even container pans for computers and other electronic devices.
1. A method of forming a pan with a pan base comprising parallel integral raised elongated rib features, the method comprising;
extruding a billet along an axis of extrusion to form an extrudate, then cutting the extrudate in a direction perpendicular to the axis of extrusion to form one or more extruded workpieces, each workpiece comprising a rectangular, generally planar base with two opposing base sides being the lateral sides of the extruded workpiece and the other two rectangle sides being transverse to the direction of extrusion, the planar base being formed with a plurality of parallel ribs extending upwardly from a common surface of the base and extending from one transverse side of the base to its opposing side, the ribs being spaced from the lateral sides of the base;
cutting rib portions from the transverse sides of the base to provide a preform for the shaping of opposing pan walls; and
forming a pan by urging the pan preform against a die surface in a pan-shaped die cavity to form pan walls, with corner intersections, from the lateral sides of the base and from the transverse sides of the base from which rib material was removed.
2. The method of claim 1 wherein rib portions are removed by machining.
3. The method of claim 1 wherein any excess material at the corners of the pan is trimmed from the pan by shearing.
4. The method of claim 1 wherein ribs are of suitable width and height to accept a threaded fastener.
5. The method of claim 1 further comprising fabricating holes in the pan by drilling or punching.
6. The method of claim 1 wherein the forming is hot forming conducted at a temperature range of from 300-500° C.
7. The method of claim 1 wherein the forming is hot forming conducted by application of gas pressure to one side of the extruded workpiece to urge it against a shaped die.