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It is a well-established fact that when equidistant tool paths are used for 2.5D milling operations tool load varies based on the functions of path curvature. This phenomenon makes the optimal selection of cutting parameters more difficult, and the local load peaks are also detrimental to machining stability and tool life. Numerous publications address possible solutions to eliminate the problems caused by varied cutting parameters. The best solution for this is to keep the cutter engagement at a constant value. Nowadays, several methods are available to generate tool paths which are able to maintain constant cutter engagement, but the widespread use of such solutions is significantly hindered, because in this scenario complex calculations are required. This article offers a solution to this problem by presenting a new non-equidistant offsetting method for ensuring a constant cutter engagement angle. The algorithm developed for this purpose is based on simple geometrical equations and allows for its widespread use just like pixel-based methods. Concerning this new solution, computation needs and uniform tool load are verified by simulation and through experiments. The experiments have shown favourable results. Keywords Tool path generation. Cutter engagement. High-speed milling. Cutting force. Non-equidistant offsetting Nomenclature a e Effective radial immersion [mm] a p Axial depth of cut [mm] c(t) Parametric representation of workpiece contour [{mm, mm}] f z Feed per tooth [mm] h ex Maximum chip thickness [mm] i, j Step index [−] n Spindle speed [1/min] p(t) Parametric representation of tool path [{mm, mm}] r tool Tool radius [mm] s Stepover [mm] t Free parameter of curve equations [−] v Feed vector [{mm, mm}] v c Cutting speed [m/min] v f Feed rate [mm/min] w Trochoidal step [mm] z Number of teeth [−] C Entry point of the cutting edge [{mm, mm}] D tool Tool diameter [mm] MRR Material removal rate [mm 3 /min] P Tool path point [{mm, mm}] Q Exit point of cutting edge [{mm, mm}] V(x, y) Vector field [{mm, mm}, {mm, mm}] a, β Angle parameters [ ∘ ] Δs Stepsize[−] θ Cutter engagement angle [ ∘ ]

Abstract:In cutting research, the determination of the spatial force system of cutting processes is extremely important. Therefore, the forces generated need to be measured with high precision. In this paper, the development of a special three-component dynamometer system is presented for the measurement of small forces (0…100 N) in three directions during fine cutting, with a precision of 0.1 N. The designed dynamometer employs a piezo-electric cell and can easily be mounted on the tool post with only small modifications to the tool holder. The setup was calibrated for sensitivity, static load and range. By using error functions, the relative error in the measurement of force is kept below 1.5%.

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The machining of aluminium parts has been made more important in recent years and decades. The aluminium alloys are used by the automotive, aero and war industrys increasingly because of their numerous good advantageous mechanical and chemical properties. The most often used cut types are the so-called AlMgSi alloys, of which the most widespread are the reinforced silicon alloys. The surface roughness capacity of a diamond tool was examined by design of experiment. Reduced empirical equation was chosen between the cutting paramters and the measured roughness. The optimal area of cutting parameters was defined.