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QA45—50型棒料精密剪断机有两个特点:一是剪切速度高,最大剪切速度达7.5米/秒,二是剪切模具采取了封闭式的套筒模。由于上述两个特点,在剪切时就出现了普通棒料剪断机不存在的“啃头”问题。所谓“啃头”,系指当动模中剪去部分或固定模中剩余部分甚短时(据统计,对于由35.5毫米的冷拉棒料发生啃头的最大长度L_啃=13毫米),剪切面不是垂直于棒料轴线的平面,而是倾斜角很大的错移面,结果将棒料啃去一个角(图1)。从理论上分析,这是由于剪切时的弯矩和水平分力
QA45-50 bar cutting precision cutting machine has two characteristics: First, high shear rate, the maximum shear rate of 7.5 m / s, and second, shearing mold to take a closed sleeve die. Due to the above two characteristics, there is a problem of “eating head” which does not exist in ordinary bar cutting machine when shearing. The so-called “eating head” refers to when the movable part of the crop or the remaining part of the fixed mold is very short (according to statistics, for 35.5 mm of cold drawn bar head material occurred to eat head maximum length L nibbling = 13 mm) , The shear plane is not a plane perpendicular to the axis of the bar, but a misaligned surface with a large angle of inclination, which results in the bar being gnawed to a corner (Figure 1). Theoretically, this is due to the bending moment and horizontal component of shear force