Usually, the heading dies has the structure of the WC-Co (Carbide) with the dies steel which reinforcing the WC-Co(Carbide).
Since the WC-Co (Carbide) is brittle materials and very expensive, all dies might not be made of the WC-Co (Carbide).
We produce the die material by making a hole to the dies steel and then into that hole inside implementing with the shrinkage fit and press-fit
Then, we would do the whole processing with the small hole electric discharge machining, the wire cut electric discharge machining and the sinker electric discharge machining to the WC-Co (Carbide) part. This part becomes the core where, actually, is used for component production. Therefore, we finish it in a mirror surface condition by the lap processing in the hole inside. Depending on its quality, the life-time of the die could be changed several times more. Even if it is said that the lap processing records life on a die, that is no exaggeration.