OBRABOTKAMETALLOV Vol. 26 No. 2 2024 technology a b Fig. 6. Model (a) and appearance (b) of the experimental stand with an installed dynamometer, a specimen and a mill testing. The Kistler dynamometer mod. 9257BA for measuring cutting forces was mounted directly on the table of the milling machine. The specimens were milled both along and across the build direction (see Fig. 1). In this case, it is important to track the influence of the specimen build direction on the change in cutting forces and the roughness of the have machined surface. Milling was carried out without the use of a coolant to minimize the influence of the cooling factor and lubrication of the cutting zone. The cutting modes were adopted according to Table 5 in order to experimentally determine the highest possible feed according to the strength of the cutter and its teeth, that is, for the increased volume of the chip being cut Q. Attempts to increase the cutting speed and feed above the table values inevitably led to the failure of the mill after the first seconds of operation (Fig. 7). During the tests, conventional or up milling was used according to the scheme shown in Fig. 8. Adistinctive feature of conventional or up milling (counter milling) from climb or down milling (passing milling) is that during conventional milling, the uncut chip thickness ai increases from zero to the maximum value at the moment the tooth leaves contact with the workpiece. This allows for a short period of time to ensure smooth loading of the cutting edge, unlike in climbmilling, when there is an abrupt load in the first moments of cutting, often leading to premature destruction of the cutting edges. Ta b l e 5 Milling modes Experiment No. n, rev/min V, m/min Fmin, mm/min t, mm B, mm Q, mm3/min 1 2.000 75 120 1 7 840 2 240 1.680 3 480 3.360 4 850 5.950 5 2 11.900 6 2.5 14.875 7 2.500 94 8 3 17.850 9 1.050 22.050
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