Why must the knives have changed more frequently? How can you optimize the cutting quality?
Non acceptable cutting quality can be a result of the following:- Wrong knife adjustment (adjustment between top- and bottom-knife)
- In-run time of the knives too short
- Wrong choice of the knife quality related to the product to be cut
- Problems while cutting high grammages resp. higher paper grades or multiple layers
- Knife geometry and tolerances are not in line with the OEM guidelines
- Grinding errors
- Paper dust and clay
How to optimize cutting quality
The used material grade has a lesser impact on the cutting quality then parameters such as surface roughness, cutting angles, knife hardness (HRC), knife tolerances or machine conditions.
The better the knife surfaces are polished (standard 400µm vs. mirror-polished 30µm) and the tighter the tolerances are defined (parallelism up to 30µm, cut-edge-straightness standard TKM 100µm / 1000 mm) the higher cutting qualities will be achieved. Some material qualities can be polished easier, which results directly into higher cutting qualities (steel qualities vs. HSS alloyed powder metal steel grades vs. tungsten carbide materials) Higher material grades and grammages (approx. 600gsm with multiple layers) and optimized cutting qualities can be often achieved while grinding less sharp knife geometries and angles.
We recommend:
TKM sheeter and cross cutting knives are available in tightest tolerances and mirror polished surfaces. All products always fit to your individual cutting application. Our service specialists will find the best set-up procedures with the ideal price/performance ratio. Book our best practice “slitter and sheeter training courses”; this will optimize your cutting processes.
