Cold forming process explained
Cold forming is a manufacturing process by which metal is shaped without removing material. A simple blank (either sawn or cropped from around bar or wire or as a cold headed pre-form) is placed within a die, and a punch is pressed into the blank at ambient temperature. The blank then takes on the form of the punch as well as the die. Put more simply; cold-forming is making a shape from material at room temperature, just like Plasticine when it is pushed into a mould. With appropriate force, metals such as copper, aluminium, brass and now even stainless steel can be formed into the required shape.
In cold forming, the metal is stretched beyond its yield strength, so that it takes on and retains the exact shape of the mould, but without adversely affecting its tensile strength. Unlike conventional machining, where the material removal processes cut across the grain structure of each part, cold forming allows the grain structure of the material to follow the contours of the die or mould. As a result, the strength of the part is maximised along its length, while internal surfaces take on a highly polished finish.
Cold forming is a fast, economical way to produce robust, complex components in a wide range of materials. The process is capable of delivering precision engineering parts with up to 80% less scrap than machine processes. Cold forming offers faster lead times, better surface finish and improved mechanical characteristics. Manufacturers across the industry can then take advantage of enhanced component quality while also reducing costs.
How cold forming shapes up against other methods?
Lower Costs (Reduced Material & Production Costs
up to 80% material savings can be achieved, as well as time and costs saved machining would have otherwise incurred that.
Faster Lead Time
As it is performed at ambient temperatures, cold forming is a far quicker process than more conventional options, allowing manufacturers to achieve much shorter production processes. This, in turn, means that components can be made to order extremely quickly, cutting lead times and the need to store high volumes of spare parts on site.
Cold forming makes for superior quality products by plasticizing metals along with their grain boundaries, rather than cutting across. Parts are produced with extremely low levels of stress deformation also high levels of mechanical integrity, resulting in far greater performance and reliability.
Higher Quality Surface Finish
Cold forming offers outstanding levels of definition, even on parts with complex contours. Typically, dimensional tolerances can be to within plus or minus two microns, with the added benefit of extremely fine surface finishes, both internally and on the surface, which in many cases, require no further machining or polishing.
Improved Structural Integrity Machinability and Durability
Parts undergo work hardening during the cold forming process, improving their machinability and durability still further. Work hardening dislocates the structure of the metal in a way that prevents further dislocations, resulting in a stronger component. As this increase in strength is comparable to that of heat treating, it can be more cost effective to cold work a less costly as well as weaker metal than to work a more expensive metal, especially when a precision finish is required.
Accurate internal profiles also multiple external profiles are possible, enabling precision parts to be manufactured, that can have a significant impact on the performance of the equipment in which they are used. There is almost no limit to the shape, size or complexity of the metal components that can be produced using cold forming. Simple cold-headed parts or highly sophisticated cold formed and finished machined components can be generated for a diverse range of applications.