木工机床临界转速确定方法的探讨

Approach on Determination Method for Critical Rotating Speed of Woodwork Machine Tool

临界转速是木工机床设计与制造的一个主要参数，为确定木工机床主轴刚度、主轴转速的依据。试验中采用ＭＸ５１１２型木工铣床，探讨了木工机床临界转速的３种确定方法。研究结果表明：利用理论公式计算，因无法确定其中的主要参数，这一方法只能是估算；采用刀轴的动态特性方法可以确定机床的固有频率１３８、１９６、２６４Ｈｚ，但确定哪阶固有频率是机床的横向弯曲固有频率难度较大，且必须对机床的临界转速有一个预先估计，以避免横向弯曲固有频率的遗失；采用停机瞬时直测法可以准确、快捷、有效地测试出横向弯曲固有频率１８Ｈｚ，因此这种方法是临界转速确定方法中最有价值的。

Critical rotating speed, a basis for determining the rigidity and rotating speed of the main axle, is an important parameter in the design and manufacture of woodwork machine tool. Experimented with MX5112 woodwork milling machine, three method of determining the critical rotating speed were approached. The result shows that theoretical formula method, in which the main parameter can′t be determined, can only be used to estimate; the method for dynamic feature of cutter axle can determine the natural frequency 138, 196, 264Hz of woodwork machine tool, but it is very difficult to determine which natural frequency is the lateral benting frequency, and a preestimation is also needed in order to avoid the missing of lateral benting frequency; while instantaneous direct determination method with stopping machine can accurately determine lateral benting natural frequency 18Hz immediately and effectively. Therefore, the third method is most valuable.