High-Efficiency and Low-Damage Lapping Process Optimization.

Ci Song,Yuxuan Lin,Zhifan Lin,Wanli Zhang,Feng Shi

doi:10.3390/ma13030569

Abstract

The silica opticsare widely applied in the modern laser system, and its fabrication is always the research focus. In the manufacturing process, the lapping process occurs between grinding and final polishing. However, lapping processes optimizations focus on decreasing the depth of sub-surface damage (SSD) or improving lapping efficiency individually. So, the optimum balance point between efficiency and damageshould be studied further. This manuscript establishes the effective removal rate of damage (ERRD)model, and the relationship between the ERRD and processing parameters is simulated. Then, high-efficiency, low-damage lapping processing routine is established based on the simulation. The correctness and feasibility are validated. In this work, the optimized method is confirmed that it can improve efficiency and decrease damage layer depth in the lapping process which promotes the development of optics in low-damage fabrication.

Highlights

Fused silica optics with excellent surface and sub-surface qualityare widely used in high power laser system [1]
The effective removal rate of damage (ERRD) model is established to provide a theoretical reference about balancing lapping efficiency and sub-surface damage (SSD), the relationship between ERRD, abrasive type, abrasive size, pressure and velocity is simulated
W7 silicon carbide (SiC) abrasive and W20 diamond abrasive can be applied in the lapping process, while lapping pressure needs to be controlled strictly

Summary

Introduction

Fused silica optics with excellent surface and sub-surface qualityare widely used in high power laser system [1]. A high-efficiency lapping process tends to increase the depth of SSD and delay the processing cycle since the material removal rate of final polishing is rather low. Lambropoulos et al had proposed an interpretation of manufacturing featuresbased on the optical material removal micromechanical model, which could conduct the fabrication process [13]. After lapping under the optimal parameters (abrasive: Al2 O3 , grain size: 3 μm, lapping speed: 50 rpm, load: 2.8 kg), theroughness Rt of fused silica is 1.3 μm and SSD depth is 4.3 μm, while material removal rate was relatively small [14]. The theoretical model and the optimal lapping parameters can be a reference on high-efficiency, low-damage optics fabrication

Remove Rate Model and Subsurface Defect Model

ERRD Model

Simulations

Experimental Validation

Findings

Conclusions