外文翻译---铣削机床使用的能源消耗特性及减缩策略(编辑修改稿)

外文翻译---铣削机床使用的能源消耗特性及减缩策略(编辑修改稿)内容摘要：

s will be pared. Scenario (1) is the base scenario, while scenario (2) will be the scenario in which the material removal rate is increased for the purpose of reducing processing time. The constants,α andβ , were created to represent the increase in p cut and decrease in ∆t, respectively (see Equations 2 and 3). Note that both constants are less than unity. pcutcut21p (2) t 12t (3) Equation 4 shows the relationship between p avg1 and Pavg2, which assumes that the air cutting power demand, pair, remains relatively constant for both scenarios. )1(** 21p   pp a irav gav g (4) If the relative size of the air cutting power demand is denoted by: ppavgairiii  (5) 6 where i is 1 or 2 for scenarios 1 and 2, respectively, then the inequality presented in Equation 6 shows the condition that must be met in order for the energy consumption of scenario (2) to be smaller than that of scenario (1).   12 (6) So if β is less than α , then e2 will always be less than e1. Also, asη 2 increases (. if the air cutting power demand prises a large portion of the total power demand) then the probability of e2 being less than e1 increases. This would be the case for machine tools with large work volumes which have a high standby power demand. Further work can be conducted in which the assumption that the air cutting power demand does not stay constant to expand the applicability of the power and processing time tradeoff analysis. 3 CHARACTERIZING THE SPECIFIC ENERGY The specific energy of various manufacturing processes was previously summarized by Gutowski et al. [7], but for any given manufacturing process the data was limited to only a sample of process rates. This study, though, will focus on milling machine tools and the operable range of the machining center when characterizing the specific energy. In characterizing the energy consumption of a machine tool, as the . approaches infinity the specific energy is expected to reach a steady state of zero. But, given the work volume, spindle speed, and table feed constraints of a machine tool as well as the maximum loads that can be applied without deforming the main body frame or breaking the spindle motor, the operator will never reach a . anywhere near infinity. So under the constraints of the . a curve of the following form: bRRMkcut  ..1*e (7) was fit to the data from the width of cut and depth of cut experiments. Note that the constant, k, essentially has units of power and b represents the steadystate specific energy. The total specific energy, which accounts for cutting and air cutting power demand, was indeed found to have an inverse relationship with the . (see Figure 4). The air cutting power demand dominated the specific energy. The impact of the cutting power demand on the specific energy was minimal since at high loads (. at high .’ s) the machining time decreased significantly. The specific energy decreases rapidly until a . of approximately 75 mmˆ3/s is reached. For .’ s lower than 75 mm3/s, a slight increase in the material removal rate causes a sharp drop in the specific energy because machining time improves dramatically. At .’ s greater than 100 cmˆ3/s, the gain from increasing the process rate is minimal since the specific energy begins approaching a steadystate value. This gain could be significant for work pieces requiring a substantial amount of material removal, but since the machine tool used in this study is a Micromachining center a . greater than 100 mmˆ3/s would show only a minor decrease in energy consumption given standard work piece sizes. 7 Figure 4: Specific energy as a function of . The best fit model was found to be: ..1*1478  RRMecut (9) ..1*1488e  RRMcut (10) This specific energy model can be used to estimate the total energy consumed while cutting. The part features and tolerances would dictate the size and type of machine tool required for part manufacture. The optimal . can be determined using standard process parameters based on the work piece material and the appropriate cutting tool for the feature creation. Therefore, the total energy consumption while cutting can be calculated by multiplying the specific energy estimate by the volume of material removed. The machine tool analyzed in this paper is a micromachining center. Larger machine tools can process material at higher rates, therefore shifting the specific energy curve to the right. But these machine tools will also have higher standby power demand due to the peripheral equipment [8] causing an upward shift in the specific energy curve (see Figure 5 ). Figure 5: Shift in specific energy plot for larger machine tools. 8 4 EFFECT OF WORK PIECE MATERIAL ON POWER DEMAND The aforementioned experiments were conducted with a low carbon steel work piece. The type of material being machined is also a factor in the cutting power demand of the machine tool, though. A plastic work piece, for example, is expected to generate a smaller load on the spindle motor than a metal work piece and therefore result in a lower cutting power demand. Since the cutting load is expected to vary with the work piece material, the following experiments were conducted to measure the power demand of the Mori Seiki NV1500 DCG while machining peripheral cuts on 1018 steel, 6061 aluminum, and polycarbonate. A depth of cut and width of cut of 2 mm and 4 mm, respectively, was used. The chip load of mm/。