Grindability of carbon fiber reinforced polymer using CNT biological lubricant

Teng Gao,Zafar Said,Shubham Sharma,Changhe Li,Bo Liu,Yanbin Zhang,Yiqi Wang,Qinglong An

doi:10.1038/s41598-021-02071-y

Abstract

Carbon fiber-reinforced polymer (CFRP) easily realizes the integrated manufacturing of components with high specific strength and stiffness, and it has become the preferred material in the aerospace field. Grinding is the key approach to realize precision parts and matching the positioning surface for assembly and precision. Hygroscopicity limits the application of flood lubrication in CFRP grinding, and dry grinding leads to large force, surface deterioration, and wheel clogging. To solve the above technical bottleneck, this study explored the grindability and frictional behavior of CNT biological lubricant MQL through grinding experiments and friction-wear tests. Results showed that the CNT biological lubricant reduced the friction coefficient by 53.47% compared with dry condition, showing optimal and durable antifriction characteristics. The new lubrication was beneficial to suppressing the removal of multifiber block debris, tensile fracture, and tensile-shear fracture, with the advantages of tribological properties and material removal behavior, the tangential and normal grinding force, and the specific grinding energy were reduced by 40.41%, 31.46%, and 55.78%, respectively, compared with dry grinding. The proposed method reduced surface roughness and obtained the optimal surface morphology by preventing burrs, fiber pull-out, and resin smearing, and wheel clogging was prevented by temperature reduction and lubricating oil film formation. Sa and Sq of the CNT biological lubricant were reduced by 8.4% and 7.9%, respectively, compared with dry grinding. This study provides a practical basis for further application of CNT biological lubricant in CFRP grinding.

Highlights

Carbon fiber-reinforced polymer (CFRP) has become the preferred material for aerospace equipment due to its high specific strength, high specific stiffness, and integrated design and manufacturing of material structure, and good performance[1,2]
In the second stage, the friction coefficient decreased gradually because the friction removal process of the diamond ball on the CFRP plate tended to be stable gradually, and the removed fiber debris acted as a solid lubricant between the interfaces
The difference was that with the continuous grinding of diamond ball and CFRP plate, the friction coefficient of Minimum quantity lubrication (MQL) increased slowly in the third stage, and the frictional contact condition deteriorated because bio-lubricants were insufficient to form an effective lubricant film

Summary

Introduction

Carbon fiber-reinforced polymer (CFRP) has become the preferred material for aerospace equipment due to its high specific strength, high specific stiffness, and integrated design and manufacturing of material structure, and good performance[1,2]. Debonding of fiber and matrix is the first failure mode in CFRP cutting It germinates near the cutting edge of the tool and is accompanied by matrix cracking at different stages of chip formation. Fiber fracture is the last failure mode in the process of chip formation. The ability of MQL to remove heat in the grinding zone mainly relies on high-pressure gas, being unable to achieve the expected cooling effect and leading to the deterioration of the surface integrity[39,40,41]. Gao et al.[51] proved that compared with dry grinding, NMQL grinding CFRP can obtain lower surface roughness and fractal dimension, and effectively reduce processing damage such as resin coating, multifiber block pullingout, and pits. This work provides theoretical and practical basis for further research and application of CNT nano-lubricant in CFRP grinding

Methods

Results

Conclusion