Machining, Measurement, and Control Laboratory

2 0 0 0    C o n f e r e n c e    P a p e r

NC Programming for Constant Cutting Force in Die Machining
Yoshiaki Kakino (Kyoto University)
Hirotoshi Ohtsuka (Ohita Industrial Research Institute)
Heisaburo Nakagawa (The University of Shiga Prefecture)
Toshiki Hirogaki (The University of Shiga Prefecture)

This paper presents the mathematical modeling of milling processes of hardened steel for dies and molds using (Al,Ti)N-coated micro-grain carbide radius endmill cutter. An approximate quadratic polynomial model is proposed to estimate the cutting force during milling processes. It is estimated based on the response surface that is defined by the following two variables; the engagement angle of cutting tool and the maximum undeformed chip thickness. In endmilling processes of hardened steel, the control of cutting forces is especially important because chipping occurs soon when an excessive cutting force acts on the cutting edge. An NC programming scheme based on the proposed model is shown to be quite effective for constant cutting force control in profile endmilling, both on straight lines and corners. Furthermore, the proposed response surface model is also applied in the case of worn endmills that had a cutting edge with a large negative rake angle. It is shown that the cutting force control is also possible with some compensation even for worn tools.

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