【正文】 . in [3] the power demand of a machine tool is prised of cutting, variable, and constant power ponents. The cutting power is the additional power drawn for the removal of material. The machine tool used in this analysis, the Mori Seiki NV1500 DCG, is a micromachining center with a relatively low standby power demand when pared to large machining centers. Therefore, the cutting power can prise a large portion of the machine tool’s total power demand. Energy consumption for high tare machine tools was found to be primarily dependent on the processing time of the part, which is dictated by the part geometry, tool path, and material removal rate. One such method for optimizing the tool path for minimum cycle time was presented in [4]. This paper is concerned with the effect of the material removal rate on energy consumption. The material removal rate for a 3axis machining center can be varied by changing the feed rate, width of cut, or depth of cut. Since increasing the feed rate was found to have dire consequences on the cutting tool life [5], the experiments conducted herein varied material removal rate through width of cut and depth of cut experiments for the purpose of analyzing the material removal rate’s effect on cutting power and more importantly, energy consumption. Although increases in the material removal rate translate to faster machining times, the loads on the spindle motor and axis drives increase as well, resulting in higher power demand. Since our main interest is energy consumed in product manufacture, the tradeoff between power demand and machining time was analyzed to confirm that the increased loads due to faster material removal was not increasing the total energy consumed. 2 POWER DEMAND FOR VARIED .’S Since machine tool programmers and operators have an array of options when defining the process plan for part production, this analysis strives to reduce energy consumption by process parameter selection of a machine tool. Specifically, the parameters concerning material removal rate (.) were varied on a Mori Seiki NV1500 DCG while selecting appropriate tooling. The power demand was measured with a Wattnode MODBUS wattmeter. In previous work, experiments we re conducted in which spindle speed, feed rate, feed per tooth, and cutter type were varied to analyze the change in energy consumption while milling a low carbon steel, AISI 1018 steel [5]. Also, [6] conducted experiments on face milling, end milling, and drilling operations in which the energy consumption, machining cost, and tool wear were pared for increased cutting speeds. Tool wear and, consequently, cutting tool cost increased significantly when the process parameters veered away from the remended cutting conditions. So in the following experiments the cutting tool type was changed to maintain the remended process parameters, but reduce energy consumption while machining, nonetheless. Width of Cut Experiments Given the energy savings from changing the cutter type this project focused on varying material removal rate. First the width of cut was increased while machining with a: 1. 2 flute uncoated carbide end mill, 2. 2 flute TiN coated carbide end mill, and 3. 4 flute TiN coated carbide end mill. Peripheral cuts were made along the yaxis at a depth of cut of 2 mm with an 8 mm diameter end mill over a length of 101 mm in a 1018 steel work piece. The width of cut was varied by 1 mm increments between 1 mm and 7 mm, in addition to a mm width of cut. Table 1 summarizes the cutting conditions used. The chip load was maintained at approximately mm/tooth to avoid excessive tool wear and breakage. Table 1: Process parameters for width of cut experiments.Once the power was measured for each width of cut experiment,the power demand was measured for the machine tool while air cutting, that is, while running the tool path without material removal. This way the power associated with the material removal process could be extracted, known hereafter as the cutting power demand. The average air cutting power demand was found to be 1510 W for the cutter (2) process parameters, so it was subtracted from the average total power demand. Figure 1 shows the cutting power demand as a function of the . for cutter (2). This plot has a slightly parabolic trend with a point of inflection at approximately 75 mm3/s. The cutting power demand for the mm width of cut was almost nine times greater than the 1 mm width of cut. Since the total air cutting power demand was only 1510 W, though, the resulting increase in total power demand of the machine tool was only 28%. Thus in terms of energy consumption, the operator still experiences energy savings with the increase in .Figure 1: Cutting power demand using cutter (2) while cutting 1018 steel. Figure 2 shows the average power demand of the NV1500 DCG for cutters (1)–(3). The relationship between power and . shifts from parabolic to linear in moving from the conditions imposed on cutter (1) to cutter (3). The increase in power demand is the greatest for cutter (3), but the load on the spindle motor and axis drives is also much greater than that of the 2 flute cutting tools since the feed rate is twice as large or greater. Figure 2: Average total power demand as a function of . Depth of Cut Experiments Depth of cut experiments were also conducted on a 1018 steel work piece 101 mm in length. Cuts were made along the yaxis using 8 mm diameter, 2 flute uncoated and TiN coated carbide end mills under near slotting conditions (a width of cut of mm). The power demand was measured at depths of cut of 1, 2, 4, and 8 mm. The chip load was maintained constant across the various cutters at mm/tooth. The spindle speed and feed rate were varied, though, to account for higher loads on the machine tool during the depth of cut experiments (see Table 2 for a summary of the processing conditions). Table 2: Process paramet