Drop Forging Process

General closed die drop forging process includes dies making, billet cutting, billet heating, drop forging, trimming, heat treatment, shot blasting, machining, surface treatment and inspection. Below we would like to introduce the drop forging process in detail.



Step 1. Dies Design & Making

Making dies is the first step for starting drop forging process. We will first design and produce dies according to the die drawing. Such dies normally include forging dies,trimming dies and flat die. Among these dies, flat die is not necessary, as it is just used to used to flaten the products to ensure geometric tolerances.

Step 2. Billet Cutting & Heating

Normally, we will prepare commonly used materials (steel, aluminum & copper) in stock, and cutting the billet to the estimated size. Then using the medium frequency furnace to heat the billets to a certain temperature, after that deliver the heated bars to a metal frame and wait for forging.

Step 3. Drop Forging

Before forging, forging upper and lower dies will be attached to the anvil of forging press. Then workers will pick up a billet and place between forging dies so that the billet will be pressed at a high speed for several times to desired shapes.

Step 4. Trimming

After forging, we will see the redundant flash around the drop forging blanks. So removing flash is also a necessary step. Workers will first assemble the trimming dies under the punching machine, and then press the forging blanks at a time so that flash will be removed. We call this process "trimming".

Step 5. Heat Treatment

Heat treatment will help to reach the required mechanical properties and hardness. Such heat treatment processes are normalization, quenching, annealing, tempering and hardening, solution teratment, etc.

Step 6. Shot Blasting

By shot blasting, the drop forgings will look more smooth and clear. You will see a better surface finish. Normally, the surface finish of drop forging products will reach Ra6.3, whose surface is much better than that of lost wax casting.

Step 7. Machining

For some parts, drop forging process is not enough to get the required tolerance, then machining will be workable, we will do machining with different machining facilities, such as milling machine, boring machine, drilling machine, grinding machine, cnc, etc.

Step 8. Surface Treatment

In most cases, we will just do water/oil anti-rust on the surface of drop forgings if there is no special requirement. But we could also follow other surface treatment demands, like painting, powder coating, galvalization, electro painting, etc, according to the requirement of our customers.

Step 9. Final Inspection

To ensure superior quality,we must do dimension inspection.Sometimes we also need to do inspection for mechanical properties and chemical composition.

Step 10. Package & Delivery

Usually, we will pack the forgings with ploybag, and put in a strong wooden case. Such package could also be customized to meet customer's demand. Located in Ningbo, both Ningbo seaport and airport are very convenient for us to deliver products to our customers' destination port.