Grinding machine knives: the cutting edge makes the difference

Machine and industrial knives are reground several times: during knife production, when the cutting edge is created for the first time, and later when the knife has to be reground to restore a sharp cutting edge.

Which knife types are ground (Excerpt):

• Long knives and planer knives for paper and board processing
• Rotor and granulator knives for recycling and plastics processing
• Circular knives for food processing
• Slitting knives and band knives for leather processing
• Planer and veneer knives for woodworking
• Chopper and mower knives for agricultural machinery

As different as these knives are, their requirements are similar. The main priorities are a sharp cutting edge with a clean ground finish and low heat input. If the cutting edge becomes too hot during grinding, the microstructure in the surface zone can change and the steel may lose hardness in this area. Alternatively, a brittle surface layer may form while the steel beneath it remains soft. Excessive heat input shortens the service life of the cutting edge and therefore of the knife. As a result, the knife has to be reground sooner.

Segments in ISO shapes or custom-made

Grinding segments are used very frequently. They are mounted in the segment holder and replaced individually. The gaps between the segments allow coolant to reach the contact zone and swarf to be removed from the grinding zone. This is one reason why segments are effective at limiting heat input into the cutting edge.

We manufacture segments both in standard ISO shapes and in custom-made for knife grinding machines. Please specify the required shape and dimensions in your enquiry. You can find an overview of the shapes in the Grinding Knowledge section of our website: https://zische.com/en/grinding-knowledge/shapes/.

Cup grinding wheels and grinding rings

In addition to segments, we manufacture highly porous cup grinding wheels and grinding rings. The open pore structure provides space for swarf and allows coolant to reach the contact zone. It therefore helps determine how effectively heat input into the cutting edge can be reduced.

We select the specification for your application

We define the abrasive material, grit size, hardness, structure and bond on the basis of our experience. Depending on your application, process parameters and knife material, we use high-purity aluminium oxide, sintered aluminium oxide and mixtures containing silicon carbide.

We select a vitrified or resin bond according to the requirements for the ground finish, stock removal and cool grinding in your application.