What Is Impression Die Forging?
When most people think of “forging,” they picture a blacksmith striking hot steel with a hammer. In reality, the industrial forging process is much more complicated than that. In fact, “forging” isn’t just one standard process. There are several ways you can create forgings, and each manufacturer has their own specific way of carrying out their own forging process.
Impression die forging is an example of just one type of forging technique that a manufacturer may use to mass produce forgings for a wide array of industries.
Impression die forging is a metal deformation technique in which a billet is compressed between two sets of die to form a complex part. “Impression” refers to the pre-cut profile of the dies used during the forging process, which are customized based on the part that is being produced.
Depending on the component’s design, impression die forging may require one set of dies or a multi-stage process with many sets of dies.
With multi-stage forging, a part can move through busting, blocking, and finishing dies. The first two stages help form the part’s initial construction, while the finishing dies fine-tune geometrical details without significantly changing the item’s shape or increasing material flow.
Impression die forging can be carried out either using a drop hammer or forging press. The technique will vary slightly based on the equipment that’s being used.
During the impression die forging process, a pre-cut billet that’s been heated to a pre-determined temperature is placed between two sets of custom dies/tooling. As previously mentioned, each die contains a pre-cut profile (or cavity) that resembles what the final product will look like.
The billet then undergoes controlled deformation as it is compressed between the two dies. Depending on the forging being made, there may be more than one set of dies involved in the process. While the billet is being compressed, excess metal (flash) will flow and cause pressure to build up within the die. Since flash cools down more quickly than the metal inside the die, it blocks more hot metal from escaping and turning into more flash. This also ensures that the remaining hot metal fills up the die and creates a more uniform product. Once this forging process is complete, the flash is removed, and the final product is left to cool. Once the forging has cooled, it’s cleaned off and inspected.
Impression die forging is very effective for shaping aluminum, steel, titanium, and a wide range of metal alloys. By enclosing the hot metal inside sets of dies, many kinds of complex three-dimensional shapes can be produced. This includes simple forms such as cubes, disks and spheres, but it can also be applied to multi-section parts that incorporate thin delicate webs and long, spindly shapes.
Impression die forging is also useful for parts with holes, pockets and protrusions, and even asymmetrical parts can be produced through this process.
Thanks to this forging process, high-quality components can be manufactured at a relatively reasonable cost. The resulting parts resist both fatigue and impact, are very durable and have higher strength-to-weight ratios. Sometimes, these parts are up to 20% stronger than those produced by other forging methods. Impression die forging also generates less wasted metal, and this refined method is capable of higher production rates than other techniques.
This forging technique is used in many manufacturing applications. You’ll commonly find forgings in the automotive industries as well as the railroad, mining, aircraft, aerospace and defense industries.
Impression die forging is just one of the many capabilities that Trenton Forging offers. With 3D printing and laser scanning, machining, die welding, machining, tooling and other processes, we deliver high-quality forgings to clients in many industries. We look forward to helping your company meet its needs, contact us today!
