The influence factors of shear aluminum strip edge step quality

Release time：2014-11-06

　　The shearing quality of strip is the key to measure the longitudinal shearing machine.

　　Effect of shearing strip edge quality factors are: the upper, lower knife overlap, side clearance,uniform shear strip hardness.

　　1, the amount of overlap

　　The amount of overlap is the correct assurance strip produce an optimal bite into continuity inshear angle and torque under the action of shear does not jump knife keep in shearing. On the tensile strength, thickness, size and the strip strip overlap after tension, shear stress, the cutting tool machining accuracy.

　　In actual use because of the action of shear force in the slitting machine, knife shaft knife shaftdeflects, the middle position of the largest amount of knife shaft deflection, the amount of overlap will reduce the position of the cutter, serious when can produce local jump knife case.So when the cutter shaft shear limit maximum deflection for shearing strip thickness 20%, is guaranteed to check the cutter shaft strength, does not affect the correct shear a prerequisite for the design overlap, related compensation and limit the amount of overlap in the automaticknife set in the system, the upper and the lower cutter shaft parallelism is also critical thatrequires its parallel degree greater than the thickness of the strip in 4%, use should often usespecial detection tool calibration. The machining precision of the cutting tool is a high precisioncontinuous shear guarantee, with the precision cutter shaft and a cutter hole is very important,the existence of the gap presence knife eccentric cutter rotary cutting, eccentric is too large will occur discontinuous shearing phenomenon, the basic requirements of hole matching thereforeknife shaft and the knife is h5/H6 with the previous due to limited processing ability can not meet the requirements. So it is with the cutter shaft of hydraulic expansion method to solve the problem, the complexity of its structure, limited role, and now with the machining accuracy improvement, ensure the knife shaft and the inner hole knife fit tolerance within 0.01 mm is not difficult, as the overall consistency of the cylindrical grinding knife the main requirements of the outer circle of the coaxial knife tolerances. It is the guarantee for shear key strip shearing qualitywhen the minimum thickness, because the minimum thickness limit theory disc cutter shearingstrip 0.05 mm, high tensile strength, thickness is less than or equal to 0.35 mm with / foil is the range of cutting disc spring knife and razor blades. Overlap adjusting modern slitting machineadopts digital automatic adjustment, backlash, overlap edge cutting machine knife disk has beenthe realization of digital automatic adjustment.

　　Side clearance 2, knife

　　The side gap of the upper and lower circular knife determines the shearing strip edge qualityknife, right side gap case after cutting edge strip can be divided into: the deformation zone,shear zone, tear, burr area four parts. Shear zone and tear area neat, smooth surface, shearzone accounts for 20 - 45% of the thickness of the strip, the strip thickness larger shear zone is relatively larger; burr height depends mainly on the knife backlash, and burr height should not exceed the strip thickness of 3 - 5%, generally should not exceed 0.04 mm, if more than 0.04 mm hand inspection will produce the feeling. High precision cutting burr height after the stripstrip thickness below 1%, the minimum is only a few microns.

　　Shear backlash is too large when the strips in the upper and lower knife between the distortion,the shear zone smaller tearing area larger, leading to a greater shearing strip edge burr.

　　Shear clearances after hours can cause damage zone, damage zone had harmful friction torque, strip staggered irregular damage zone face greater wear on the disk edge, makes thedisc blade dull quickly, reduce shear life of knife, at the same time more "hair" shaped aluminumchips produced in the strip shear zone. Shear knife side gap size tensile strength, mainly with the shearing of the material thickness, the aluminum strip, shear knife backlash correct for the strip thickness of 3-8%, the tensile strength is big, when the thickness is big backlash takes great value.