Forgings often require some additional finishing. Filing, grinding, and honing are common operations used to refine surfaces or change the geometry of the part. This includes changing the radius of internal and external corners, transitioning from a flat surface to a curved surface, or adding a draft angle to an internal corner to aid in molding operations. If these parameters must meet specific tolerances, they become part of the degrees of freedom in a forging design.
Radius and draft tolerances on forgings must often meet very tight requirements in order to function as designed. In general, more elastic materials like carbon steels, low-alloy steels, and aluminum alloys are able to accept tighter radii than materials that are harder and less elastic such as stainless steels, cast irons, and nickel base alloys.
The radius tolerance is an important consideration in the design of the forged part. The reason for this is twofold. First, it can affect the final geometry of the part by limiting the curvature of the surface. Second, it can also affect the tool design, as the tool must be able to replicate the shape of the part within the given tolerance.
The draft tolerance is also important in the forging process. It is the difference in the angle between two parallel surfaces. It is used to ensure the part is released from the die during forging operations. The degree of draft tolerance will vary depending on the size of the part, the material of the part, and the application.
Another important criterion for forgings is the tooling angle, which is the angle between the part and the die. This is also dependent on the material, size, and application. A tooling angle that is too steep can cause difficulties in the forging process by not allowing the part to reach its desired shape, while an angle that is too shallow can cause excessive thinning of the part and increase the risk of cracking.
In conclusion, radius and draft tolerances need to be carefully considered when designing and making a forged part. Different materials will require different radii and draft angles, so it is important to select the right material for the job. The tooling angle must also be taken into account, as it can affect the part’s geometry as well as the forging process. All in all, taking into account these parameters when designing a part and meeting the required tolerances is essential for producing a quality part.
