刀具磨损对微铣削力变化影响的理论与试验研究

摘要

The variation of micro milling forces due to the tool wear, when milling a plastic mould steel, has been investigated. Tool wear is evaluated by measuring the change of the micro tool diameter and related with the variation of the specific cutting forces. It has been found that, instead of using a constant specific cutting force Km value,variable specific cutting forces has to be used to calculate the micro milling forces with the consideration of tool wear effects. The micro milling force predicted using the modified model pro-posed in this work show good agreements with measured force values. It also shows that the monitored micro milling forces can be used as means to judge whether the change of tool size is within the preset range to en-sure the machining accuracy.%微铣削条件下加工塑料模具钢时，刀具磨损将引起微铣削力的变化。采用激光测量方法测量刀具直径的变化，用以评估微铣刀磨损情况；研究比切削力( SCF)随刀具磨损的变化关系，发现刀具磨损对于比切削力Km具有显著影响。微铣削力的计算必须考虑刀具磨损造成的比切削力变化的影响。文章提出微铣削力修正模型，所预测的微铣削力与测量出的铣削力值表现出良好的一致性。采用本模型，可预测加工过程中的微铣削力，还可通过监测微铣削力的变化判断刀具尺寸是否在预设范围内，从而确保铣削加工的精度。