Modeling and Distribution Laws of Drilling Force for Staggered Teeth BTA Deep Hole Drill

Xubo Li,Lingfei Kong,Bian Guo,Jianming Zheng,Yan Li,Weichao Shi

doi:10.1155/2018/3691468

Xubo Li, Lingfei Kong + Show 4 more

Open Access

https://doi.org/10.1155/2018/3691468

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Abstract

The boring and trepanning association (BTA) deep hole drilling is a typical self-guiding machining method. The drilling force and its distribution laws along the cutting radius directly affect the stability of drilling and the quality of machined hole. Based on the oblique cutting theory, a novel drilling force model is developed to predict the thrust and torque for staggered teeth BTA deep hole drill with variable geometries. Using the constraint relationships between the cutting force components and cutting angles, combined with the measured drilling force during the drill entrance, the parameters of the model including normal shear angle, normal friction angle and shear stress involved in the cutting force coefficients along the cutting radius, and the axial and circumferential friction coefficients between the guide pads and the hole wall are obtained. The model-predicted drilling force is validated by experimental results.

Highlights

The boring and trepanning association (BTA) deep hole drilling is commonly used in high precision and high length-to-diameter ratio deep hole machining in the field of new energy, aerospace, and military industries [1, 2]
Gao et al [15] exposed that the chip thickness deformation coefficients and the drilling force for staggered teeth BTA deep hole drilling are consistent with the cutting radius
The average errors of thrust and torque produced by cutting of the teeth are 6.07% and 5.28%, respectively, and the average errors of thrust and torque produced by burnishing of the guide pads are 6.93% and 6.50%, respectively.The results show that the model can accurately predict the distribution of cutting force with the cutting radius and burnished friction force of guide pads

Summary

Introduction

The BTA deep hole drilling is commonly used in high precision and high length-to-diameter ratio deep hole machining in the field of new energy, aerospace, and military industries [1, 2]. Gao et al [15] exposed that the chip thickness deformation coefficients and the drilling force for staggered teeth BTA deep hole drilling are consistent with the cutting radius. Astakhov et al [16, 17] used the constraint relationship between the chip thickness deformation coefficients and the shear angle to establish a drilling force model with the cutting radius distribution. In order to improve the stability of the drilling and the quality of the machined hole, the appropriate width and angles for the teeth and guide pads should be selected; the distribution laws of the cutting force with the cutting radius need to be clarified. A new method of modeling the drilling force of the staggered teeth BTA deep hole drill with variable geometries is proposed based on the oblique cutting theory. This study will lay a fundamental for optimizing the drill structure and the drilling process parameters

Drilling Force Model

Identification of Model Parameters

Findings

Experiment and Discussion

Conclusions