麻花钻锥形钻尖刃磨参数的优化

Optimization of grinding parameters for conical drill point of twist drill

为了减少麻花钻在加工过程中的轴向推力和扭矩,对其锥形钻尖的刃磨参数进行优化。首先将钻尖几何形状参数化,获得钻头横刃和主切削刃的离散模型并用于计算钻头的推力和扭矩,通过钻削试验验证了力学模型的计算精度。然后建立分别以推力、扭矩、推力与扭矩加权和最小化为优化目标,以钻尖刃磨参数为优化变量的模型,并采用遗传算法进行求解。根据优化结果确定了3种优化目标下的钻头最佳几何形状。采用优化后的麻花钻进行钻孔试验,结果表明,与标准麻花钻相比,其推力和扭矩大幅降低,同时钻头推力和扭矩的计算值与实测值误差也均在8.4%以内,误差相对较小,证明了该优化方法的有效性。

In order to reduce the axial thrust and torque of twist drill during the machining process,grinding parameters of this conical drill point were optimized.First,the drill tip geometry was parameterized,and discrete models of the chisel edge and main cutting edge were obtained and used to calculate the thrust and torque of the drill tip.Calculation accuracy of the mechanical models was verified by drilling tests.Optimization models were established which took respectively the minimization of thrust,torque and weighted sum of thrust and torque as the goals,grinding parameters of drill point as the variables.Then the models were solved by genetic algorithm.According to the optimization results,the best shapes of drill heads were determined under the three optimization goals.Drilling test results show that the thrust and torque of the optimized twist drills are greatly reduced compared with those of standard twist drill.At the same time,the errors between the calculation and measured values of thrust and torque are all within 8.4%,which are relatively small and testify the effectiveness of the proposed optimization method.