An analytical approach to cutting force prediction in milling of carbon fiber reinforced polymer laminates

ABSTRACT

A prediction model of cutting force for milling multidirectional laminate of carbon fiber reinforced polymer (CFRP) composites was developed in this article by using an analytical approach. In the predictive model, an equivalent uniform chip thickness was used in the case of orthogonal plane cutting, and the average specific cutting energy was taken as an empirical function of equivalent chip thickness and fiber orientation angle. The parameters in the model were determined by the experimental data. Then, the analytical model of cutting force prediction was validated by the experimental data of multidirectional CFRP laminates, which shows the good reliability of the model established. Furthermore, the cutting force component of flank contact force was correlated with the surface roughness of workpiece and the flank wear of tool in milling UD-CFRP composites. It was found that surface quality as well as flank wear has a co-incident varying trend with the flank contact force, as confirmed by the observations of the machined surfaces and tool wear at different fiber orientations. So, it can be known that low flank contact force be required to reduce surface damage and flank wear.

KEYWORDS:

• Average specific cutting energy
• carbon fiber reinforced polymers (CFRP)
• cutting force prediction
• equivalent chip thickness
• surface quality

Nomenclature
Fx, Fy	=	Instantaneous horizontal and vertical cutting force, N
Ft, Fr	=	Instantaneous tangential and radial cutting force, N
φ	=	Engagement angle, °
θ	=	Fiber orientation angle, °
θi	=	Instantaneous fiber orientation angle, °
Ac	=	Undeformed chip area, mm2
${\bar{A}}_c$	=	Equivalent chip area, mm2
ac	=	Instantaneous chip thickness, mm
af	=	Feed per tooth, mm
at	=	Thickness of unidirectional laminate, mm
ae	=	Radial depth of cut, mm
aeq	=	Equivalent chip thickness, mm
v	=	Cutting speed, m/min
Ft, θ, Fr, θ	=	Instantaneous tangential and radial cutting force of UD-CFRP, N
Kt, θ, Kr, θ	=	Instantaneous tangential and radial specific cutting energy, N/mm2
${\bar{F}}_{t,\theta }$, ${\bar{F}}_{r,\theta }$	=	Average tangential and radial cutting force of UD-CFRP, N
${\bar{K}}_{t,\theta }$, ${\bar{K}}_{r,\theta }$	=	Average tangential and radial specific cutting energy, N/mm2
nθ	=	Ply number of a fiber orientation
tθ	=	Ply thickness, mm
m	=	Number of different fiber orientations
${\bar{F}}_t^{*}$, ${\bar{F}}_r^{*}$	=	Average tangential and radial force of multidirectional laminate, N
FR, FN	=	Rakeface force and flank contact force, N
${\bar{F}}_t$, ${\bar{F}}_r$	=	Average tangential and radial cutting force, N
${\bar{F}}_{t1}$, ${\bar{F}}_{r1}$	=	Average tangential and radial rakeface force, N
${\bar{F}}_{t2}$, ${\bar{F}}_{r2}$	=	Average tangential and radial flank contact force, N
α	=	Rake angle of cutting edge, °
γ	=	Clearance angle of cutting edge, °
β	=	Friction angle, °
dt	=	Diameter of milling tool, mm
μ	=	Friction coefficient
ΔFt, ΔFr	=	Variation of tangential and radial cutting force, N

Additional information

Funding

This research work was supported by the National Natural Science Foundation of China (No. 11272286) and the Science Fund for Creative Research Groups of the National Natural Science Foundation of China (No. 51221004).