When cutting paper the slight variations in height of the individual sheets accumulate to an increasing degree. These height variations may arise from the inking, which occurs during the printing process, or they may be caused by the varying thicknesses of the paper sheets themselves.
When a pile of material that is to be cut is held by the clamp in the cutting machine the upper zones are compressed more than those that are lower. These upper zones are often subjected to an excessive clamping pressure, because the entire clamping area has theoretically become smaller.
As a result, the precise deviation of the knife within the paper pile is increased. When you touch such a trimmed section, you will easily feel the wavy texture. An excessive clamping pressure and height variations will stress the knife anyway. In extreme cases the knife may break, because it tends to deflect away from excessively compressed zones by moving towards the front. Therefore, the first requirement is to always ensure that the correct clamping pressure is selected in order to prevent the knife from deflecting away from the excessive pressure area. POLAR provides automatic clamping pressure regulation.
Tips on avoiding vertical stripes:
- Check pressing force - is it too high?
- Check blade angle in relations to the cutting material
- Is it the right type of blade/machine knife for the material to be cut?
The clamping pressure is always fully automatically and correctly adjusted, depending upon the values preset for the respective material and cutting width. Large variations in height can be compensated for by placing a flexible medium between the cutting material and the clamp.
POLAR cutting machines* offer:
· infinitely adjustable clamping pressure: 150 - 7000daN*
· automatic clamping pressure regulation for accurate cutting
*Please compare the technical data relevant for the individual machine variants