Guide to Selecting the Overlap Amount for Upper and Lower Circular Blades in Longitudinal Shearing and Slitting
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Author : Andy
Update time : 2026-06-16 16:36:00
When slitting metal coils, thin sheets must be cut by overlapping the upper and lower blades. There is no fixed formula for calculating the overlap amount; the key principle is that, provided a complete cut is achieved, the smaller the value, the better.
If the overlap is too large, it leads to increased burrs on the cut edges and accelerated blade wear; if the value is too small, it can result in incomplete cuts or intermittent cutting defects.
For thick sheets, due to the material’s thickness, the overlap can be set to a negative value—that is, a gap is left between the upper and lower blade edges, allowing cutting without the blades needing to overlap and engage.
The overlap setting is based on the shearing percentage and then fine-tuned according to actual production conditions.
When processing ultra-thin materials, the coaxiality of the inner and outer circles of the rubber ring must not be overlooked; precision errors cannot be compensated for by relying on the rubber ring’s elasticity.
Example: When slitting 0.2 mm hard stainless steel with a shear percentage of only 5%, the corresponding overlap is 0.01 mm; the coaxiality of the rubber ring must be controlled within 0.005 mm. If the required precision cannot be met, the only option is to increase the overlap to compensate, which in turn leads to negative effects such as large burrs and rapid tool wear.
If the overlap is too large, it leads to increased burrs on the cut edges and accelerated blade wear; if the value is too small, it can result in incomplete cuts or intermittent cutting defects.
For thick sheets, due to the material’s thickness, the overlap can be set to a negative value—that is, a gap is left between the upper and lower blade edges, allowing cutting without the blades needing to overlap and engage.
The overlap setting is based on the shearing percentage and then fine-tuned according to actual production conditions.
When processing ultra-thin materials, the coaxiality of the inner and outer circles of the rubber ring must not be overlooked; precision errors cannot be compensated for by relying on the rubber ring’s elasticity.
Example: When slitting 0.2 mm hard stainless steel with a shear percentage of only 5%, the corresponding overlap is 0.01 mm; the coaxiality of the rubber ring must be controlled within 0.005 mm. If the required precision cannot be met, the only option is to increase the overlap to compensate, which in turn leads to negative effects such as large burrs and rapid tool wear.
