Carbon fibre reinforced polymer (CFRP) composites have excellent specific mechanical properties, these materials are therefore widely used in high-tech industries like the automobile and aerospace sectors. The mechanical machining of CFRP composites is often necessary to meet dimensional or assembly-related requirements; however, the machining of these materials is difficult. In an attempt to explore this issue, the main objective of the present paper is to review those advanced cutting tools and technologies that are used for drilling carbon fibre reinforced polymer composites. In this context, this paper gives a detailed review and discussion of the following: (i) the machinability of CFRP including chip removal mechanisms, cutting force, tool wear, surface roughness, delamination and the characteristics of uncut fibres; (ii) cutting tool requirements for CFRP machining; and (iii) recent industrial solutions: advanced edge geometries of cutting tools, coatings and technologies. In conclusion, it can be stated that advanced geometry cutting tools are often necessary in order to effectively and appropriately machine required quality features when working with CFRP composites.

Advanced cutting tools and technologies for drilling carbon fibre reinforced polymer (CFRP) composites: A review

https://hal.archives-ouvertes.fr/hal-02417879/document

Recent advances in drilling hybrid FRP/Ti composite: A state-of-the-art review

Drilling holes on CFRP components is inevitable for assembling process in the aviation industry. The drilling-induced damages frequently occur and affect not only the load carrying capacity of components but also the reliability. Therefore, it is of great urgency to enhance drilling quality on CFRP components. The article aims to propose a novel drill structure to change the cutting conditions at the drill exit and effectively reduce damages in drilling CFRP. Considering the drilling-exit constraint condition, a unique two-dimensional cutting model is established to represent the axial cutting of the main cutting edge at the drill exit. Based on the model, the effects of point of action and cutting direction on material removal at the exit are investigated, and the result indicates that cutting CFRP in the upward direction has positive effects on deflection limitation and damage reduction. In order to perform the upward cutting, a novel intermittent-sawtooth drill structure is proposed on the one-shot drill. The theoretical and geometrical analyses of the drilling process reveal that the cutting lips of the structure could reverse the cutting direction from downward to upward and thereby, reduce the drill-exit damages. Furthermore, drilling experiments are conducted and the drill structure is proved to be effective to reduce drilling damages as expected.

Novel drill structure for damage reduction in drilling CFRP composites

Joining of carbon fibre reinforced polymer (CFRP) composites and aluminium alloys – A review Part A Applied science and manufacturing

Experimental study on drilling mechanisms and strategies of hybrid CFRP/Ti stacks

Critical thrust force predicting modeling for delamination-free drilling of metal-FRP stacks

The usage of carbon-fiber-reinforced polymer (CFRP) composite keeps increasing in modern industries. However, the machining mechanism of CFRP, especially the microscopic machining mechanism, is not well understood yet. This paper aims to establish a force prediction model for orthogonal cutting of unidirectional CFRP (UD-CFRP) in microscale. The deflection of the representative volume element (RVE), composed of a single fiber and the surrounding matrix, is analyzed considering the effect of the surrounding materials based on the minimum potential energy principle (MPEP). The critical force in the cutting edge that causes fracture of the RVE is obtained according to the bending deflection expression of the RVE. In addition, by taking slipping, peeling, and bounding mechanism in three different deformation areas into consideration, a force prediction model of UD-CFRP orthogonal cutting is established for fiber orientation ranging from 0° to γ
 α
  + 90°. Several experiments have been conducted, and the results comparison shows that the model, though approximately, has gotten acceptable agreement with the experimental results, which proves the effectiveness of the analysis method.

Microscopic mechanism based force prediction in orthogonal cutting of unidirectional CFRP

Cutting force prediction of orthogonal cutting unidirectional carbon fiber-reinforced plastic (UD-CFRP) is crucial in the reduction of machining defects. This paper aims to construct a force prediction model for orthogonal cutting of UD-CFRP using beams on elastic foundation theory and the minimum potential energy principle (MPEP) when fiber orientation (θ) varies from 0° to 180°. Models for different fiber orientation ranges were established separately, i.e., (1) 0°< θ < 90°, (2) 90°≤ θ < 180°, and (3) 0°. The deformation of the fibers was considered as a bending problem of a beam on elastic foundation. Total cutting force was composed of cutting forces from rake face, tool edge, and relief face of the cutting tool. As 0°< θ < 90°, Vlazov’s elastic foundation was introduced to calculate pressing forces between cutting tool edge and the representative volume element (RVE). The force applied on rake face was the integral value of resistant forces from those micro-elements of the curved chip based on well-established shear angle-cutting force relationships in Piispanen’s card model. When 90°≤ θ < 180°, non-uniform Winkler foundation was applied to calculate force between rake face and the RVE. When θ = 0°, the energy equation of the splitting process was constructed by using virtual crack close technique, and plugging force between rake face and the chip was derived from the equation. This mechanical model reveals mapping relationships between cutting forces and key variables such as the fiber orientation, rake angle, depth of cut, and so on. Corresponding experiments were conducted, and predictions were in acceptable agreement with the experimental measurements.

A cutting force predicting model in orthogonal machining of unidirectional CFRP for entire range of fiber orientation

An experimental investigation on interfacial behavior and preload response of composite bolted interference-fit joints under assembly and thermal conditions

Zhenchao Qi

Papers

Critical thrust force predicting modeling for delamination-free drilling of metal-FRP stacks

Microscopic mechanism based force prediction in orthogonal cutting of unidirectional CFRP

A cutting force predicting model in orthogonal machining of unidirectional CFRP for entire range of fiber orientation

An experimental investigation on interfacial behavior and preload response of composite bolted interference-fit joints under assembly and thermal conditions

Multipoint flexible positioning method and tool for automatic drilling and riveting assembly of wallboard