Modelling cutting force for turning AISI 304 stainless steel with PVD-AlTiN coated, PVD-AlTiN coated-microblasted, and MTCVD-TiCN/Al₂O₃ coated tools

ABSTRACT

Stainless steel is challenging to machine, and to avoid any negative consequences, it is essential to comprehend the cutting forces. With this view, this study has developed a cutting force model for turning AISI 304 stainless steel with the most preferred PVD-AlTiN coated (C-type), PVD-AlTiN coated-microblasted (CMB), and MTCVD-TiCN/Al₂O₃ coated carbide tools (MTCVD). Empirical models are developed to predict the chip thickness ratio, the normal shear angle, and sharp tool cutting forces. Studies showed the reduction in forces with the cutting speed for C-type, CMB, and MTCVD tools was 12–20%, 11–32%, and 6–29%, respectively. However, the corresponding increases with the feed and depth of cut were 60–134%, 125–146%, and 97–178%; 76–186%, 55–384%, and 14–274%, respectively. Additionally, a cutting force model considering the tool wear effect is developed for MTCVD tools, which exhibited lower tool wear compared to other tools. The study accurately predicted sharp tool and worn tool cutting forces, showing good quantitative agreement with experimental results with an average error of less than 10%. However, some discrepancies were observed beyond the flank wear length of 0.2 mm. It was due to the chipping of the coating layers and the pitting of the substrate from the nose area.

KEYWORDS:

• AISI 304
• modelling
• cutting force
• coated tools
• flank wear
• oblique cutting

Abbreviations and symbols

AlTiN	=	Aluminium titanium nitride
Al2O3	=	Aluminium oxide
C-type	=	PVD-AlTiN coated tool
CMB	=	PVD-AlTiN coated-microblasted tool
MTCVD	=	MTCVD-TiCN/Al2O3 coated tool
TiCN	=	Titanium carbonitride
w	=	Width of cut
$c_c,c_f,c_r$	=	Model constants
d	=	depth of cut
f	=	Feed
$F_c,F_f,F_r$	=	Predicted sharp tool cutting forces
$F_c^{\prime },F_f^{\prime },F_r^{\prime }$	=	Predicted revised sharp tool cutting forces
$F_c^{"},F_f^{"},F_r^{"}$	=	Experimental sharp tool cutting forces
$\mathrm{\Delta }{F}_{cw}^{"}$, $\mathrm{\Delta }{F}_{fw}^{"},\mathrm{\Delta }{F}_{rw}^{"}$	=	An increase in cutting forces due to tool wear alone
$F_{\mathit{cw}}$, $F_{\mathit{cw}},F_{\mathit{cw}}$	=	Predicted cutting forces due to tool wear effect
$F_{cw}^{"},F_{fw}^{"},F_{rw}^{"}$	=	Experimental cutting forces due to tool wear effect
i	=	Inclination angle
$k_c,k_f,k_r$	=	Regressor coefficients for revised sharp tool cutting force model
$k_{\mathit{cw}},k_{\mathit{fw}},k_{\mathit{rw}},p_i$, $q_i,r_i,s_i$	=	Regressor coefficients for cutting force model considering tool wear effect alone
r	=	Chip thickness ratio
t	=	Uncut chip thickness
$t_c$	=	Chip thickness
V	=	Cutting speed
${\alpha }_n$	=	Normal rake angle
${\mathrm{{\rm Y}}}_s$	=	Side cutting edge angle (SCEA)
${\mathrm{\varnothing }}_n$	=	Normal shear angle
${\eta }_c$	=	Chip flow angle
${\lambda }_n$	=	Normal friction angle

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article. However, the additional information that support the findings of this study are available from the corresponding author, [SC], upon reasonable request.