METAL FORMING METHODS

TECHNIQUES:

- Press Forming:

• Is carried out with the material at room temperature. The process relies heavily on the ductility of the material being pressed. If insufficiently ductile, the material may have to be annealed to increase its ductility.
• Press-forming is carried out using a punch and a die which are both manufactured from toughened die-steel; this makes them resistant to impacting loads, and wear from contacting the material being pressed.
• Car body panels are pressed from mild steel sheet to produce the vehicle's overall shape once assembled. The complex shapes produced require the generation of very high stresses to overcome the resistance of the materials being pressed.

- There are advantages of pressing a sheet material to a more 3-D shape, including that of great increased stiffness. This has the benefit of reducing the amount of material necessary to build the vehicle to a good safety standard.
- In addition to forming to shape, press tools can also incorporate shears to cut sections away. For example, cutting the holes in a car body for the windows and door panels. Other examples of press formed sheet materials include domestic radiator panels, kitchen products such as meat trays and cooker tops.


- Cupping:




















- Deep-Drawing:


- Drop Forging:

• Drop forging is used where larger numbers of similarly shaped objects are required, for example spanners and hip replacement joints. Drop forging is a refining process. For example, a piece that has been drawn down to a rough shape will be placed between a pair of drop forging dies.
• The upper half it attached to a vertical sliding hammer. Very large forces are exerted onto the metal blank between the die halves, forcing it into the shape of the dies. It is usual that the component being produced will pass though a number of dies before the final shape is achieved.

- Advantages of drop forcing:
---> To highlight the advantages of drop forging over casting and cutting to manufacture a product we can use an engineer's spanner as an example. These advantages also apply to other products where large forces may be applied and where it is essential that the product does not fail, e.g g-clamps, engine pistons and crankshafts.

SPINNING:


• Spinning is a traditional process used for forming 3-D hollow objects from flat sheet metals. The process involves a measured circular sheet of material which is gripped in a machine similar to a lathe.
• Products manufactured in this way include saucepans and woks, prior to having a handle fitted. The tell-tale signs of spinning are the concentric lines around the outside of the product, denoting the path of the tool.

-          Sintering – a process whereby powder particles are fused together at their contact points between other particles.

-          The process of sintering:    relies on the materials being crushed into a powder, the powder is compacted into a die which will eventually give the product its final shape, the compacted shape is then heated to promote bonding between the particles of the material.

-          Typical products manufactured in this way are cutting tool tips and hard magnetic products made from cobalt.

-          Also used in the ceramics industry

-          Also known as powder processing - the range of manufacturing processes for metal or ceramic powders.

-          The process is exactly the same for cements as it is metals

-          Sintering is an appropriate process for materials that are difficult to process in any other way.