Do you need help?
+49 2206 605-0
Do you need help?
+49 2206 605-0

Circular knives and case cut-off knives

We are happy to offer you individual dimensions in addition to the standard ones.

Diameter 50–240 mm
Areas of application Paper, cardboard, labels, adhesive tape / film, foil, plastic / nonwoven, textile, special materials
Cutting with DIENES circular knives.

Circular knives and case cut-off knives from DIENES

Dust accumulation, short service life, unclean cut edges, uneven roll surface, adhering adhesive and dimensional stability of the cut rolls are all issues we have dealt with extensively for decades. Circular knives and core cut-off knives with bevels on both sides are usually used to cut cores.

DIENES offers innovative solutions for all aspects of case cutting, using the following cutting methods:

  • fixed circular knives that cut into the rotating sleeve
  • driven circular knives that cut into the rotating sleeve

We have dealt in depth with the optimization of tool life through improved knife materials and surface quality. In addition, we are happy to help you improve manufacturing tolerances and optimally adjust the cutting geometry and knife hardness.

Using circular knives and case cut-off knives

During winding the following happens; on the winding shaft the cores are fixed to receive cut tapes, while the spaces between them are filled with loose cores as spacers. After production start of the slitter rewinder, the adjacent cores, i.e. both fixed and loose cores, rub against each other, creating a certain gap. The result is slight telescoping of the cores. This causes the so-called “gramophone effect” to appear on the wound roll.

Therefore, depending on the cardboard core outside diameter and core thickness, the chamfer geometry must be adapted to the requirements. To avoid chipping, the cutting edge on both sides is often not ground completely sharp.

In addition, the centricity of the knife edges is an essential factor for the quality of the knife and the edge is often visually checked. If core-cutting knives are used in pairs or in larger numbers, the knife edges must be ground absolutely symmetrically so that no misalignment occurs on the cut cores.

Nowadays, high-speed steel knives have almost completely replaced the usual cold-work steels due to their longer service lives. In the case of fixed circular knives, these are pressed against the rotating cardboard sleeve by hand or by machine. A plastic tube or an induction- or nitride-hardened shaft serves as a mandrel for the cardboard sleeve and at the same time as a knife stop. Depending on the thickness and diameter of the cardboard sleeve, it makes sense to lubricate the knives with silicone via a drip oiler.

Fixed case cut-off knives are turned further in cycles, if necessary, in order to transfer the knife wear to the entire circumference. Signs that the knives are becoming blunt are the rounded cutting edges that are pressed downwards due to the cutting pressure.

Sleeve tapping stations from DIENES

In slitting, the cut individual webs are usually fed either to a common winding shaft or to two winding shafts. The length of the cardboard tubes to whose circumference the individual webs are glued and wound corresponds to the cutting width set at the slitting station.

The core cutting station consists of a crossbeam on which one or more knife holders are located on linear guides. The knife holders are moved into the respective cutting position by a servo motor located on the linear module. The core cutting station is electrically connected to the fully automatic knife adjustment system of the slitter, so that the core lengths correspond exactly to the set cutting width. By means of freely selectable correction dimensions, the lengths of the cores can be designed so that they vary by a certain amount compared to the cutting widths.

Pneumatically operated knife holders for the sleeve piercing station are equipped with sharpened knives on both sides, which are set in rotation by the driven cardboard sleeve.

The scaled depth adjustment allows the vertical stroke of the knife holder to be set precisely. When using two or more knife holders, it is ensured that the repositioning for the longitudinal cuts and the sleeve separation are completed at approximately the same time.

The picture shows a fully automatic sleeve piercing station from DIENES, which is also equipped with the SIMU-FLASH simultaneous positioning system.

Your advantages

  • Precise cutting with excellent cutting edge
  • Improved manufacturing tolerances
  • optimised blade life
  • Turning by cycle possible if required

Enquiry form – circular knives

For special inquiries you can also contact our contact persons directly.

Thank you for your request. The form was sent successfully.
An error occurred while processing the form. Please try again later.
Please fill in all mandatory fields and check your entries!

Technical data

Your personal data

You might also be interested in

Slitting systems

DIENES bietet sowohl manuelle, als auch automatische Schneidesysteme an, die das korrekte Einstellen der Messer erleichtern. Informieren Sie sich hier, welche verschiedenen Schneidsysteme wir haben und wählen Sie das für Sie Passende aus.

Which knife holder suits you?

In addition to slitting systems, we also offer knife holders. A good match of knives, knife holders and slitting systems allows you to exploit productivity potentials and thus increase the efficiency and quality of your production.