For the manufacture of roll shells the specially selected steel is induction heat treated or carburised, this guarantees optimum pellet mill performance and regular wear pattern resulting in economic die and roll life.
Our dies and rolls are not only manufactured by using the most modern techniques but are also subjected to constant rigorous control prior to getting the GRAF trade mark, a mark of quality.

After the die has been turned there is still a long way to go before a GRAF Quality die is complete. In order to ensure continuity of production and quality computer numerically controlled machines, many of which were purpose designed and manufactured in our Münsingen factory, are used.

The GRAF company is also one of the first die manufacturers to use the gun drilling (special drills with built-in capillary oil cooling) method and vacuum hardening (through hardening, which takes place in a carefully controlled environment).
By using these methods of drilling and hardening it means that the surface quality of the holes in the die are smooth and stay smooth. The vacuum hardening method also means that because of negligible distortion less time is lost in remachining critical tolerance mounting surfaces. This also ensures a "round" die track and results in a smoother pellet mill operation.

Because of the manufacturing methods used, which not only guarantee a mirror-smooth hole surface but also result in a regular hole pattern, one of the most important characteristics of CNC gun drilling, the die will start without problems and produce at top capacity from start-up.

Just as importand for ring and flat die users is the GRAF quality for roll shells, available in dimpled, fine or coarse corrugated, with open-end or close-end corrugations.

Of course it is also possible to order the GRAF products online. Some special technical data will help you to choose the right type.