【正文】 高，雖然電力需求增加，但是負(fù)荷能耗仍然大幅下降。圖3：用2號刀具在不同材料去除率是的能耗和電耗 能耗與加工時間之間的平衡關(guān)系機(jī)床的能耗取決于電能消耗P avg和加工時間Δt，如公式（1）所示。方案（1）是最基本的一種方案，方案（2）是為了減少加工時間而增加了材料去除率。 (4)如果空切電能消耗量的相對比率用下式表示： (5)系數(shù)i為1或2分別代表方案1和方案2，不等式（6）為方案2比方案1節(jié)能必須滿足的條件?？蛇M(jìn)行進(jìn)一步研究，假定空氣切功率不保持不變來分析能耗與加工時間之間的平衡關(guān)系。在描述機(jī)床的能量消耗時，隨著材料去除率接近無限大時比能預(yù)計將達(dá)到為零的穩(wěn)態(tài)。切削能耗和空切能耗所占總的比能量的比例與材料去除率成反比關(guān)系（見圖4）。在材料去除率低于75mm?3/s時，一些微小的材料去除率增量都可以使得比能量大幅下降，因為加工時間顯著的減少了。零件用什么機(jī)床加工取決于零件的特性和公差要求。比這更大的機(jī)床可以以更大的切削參數(shù)進(jìn)行加工，因此可以將比能曲線向右延伸。例如塑料件加工時附加在主軸上的載荷比金屬件的要小，因此導(dǎo)致了加工塑料件的能耗更小一些。表3是實驗的加工工藝參數(shù)。加工剛健可以不用冷卻劑（這將大大的減少機(jī)床的加工能耗），但是由于冷卻液有助于排屑，并且本課題主要關(guān)注的是不同材料的加工能耗，所以各種材料的。加工鋁件時推薦使用的冷卻劑是根據(jù)鋁的延展性和在刀具表面的堆積趨勢來選定。實驗時所用的加工深度和加工寬度分別為2 mm和4 mm。4 工件材料對電力需求的影響上述實驗是用材料為低碳鋼的工件進(jìn)行的。因此，切削總能耗可以將各個材料去除體積所估算出來的比能值倍增的計算出來。當(dāng)材料去除率很大時這個增量才可以使得肉眼能識別，但是本研究使用的機(jī)床是一臺微型加工中心，一個材料去除率大于100mm?3/s在給定了尺寸的工件上只能顯示一個微小的能耗減少量而已。切削能耗對比能量的影響是最小的，因為在高負(fù)荷（也就是大的材料去除率）下，加工時間顯著減少。所以，在以上這些約束條件下得到的材料去除率可得到以下形式的一條曲線： (7)這條曲線與數(shù)據(jù)寬度切和切削深度的實驗結(jié)果吻合。但對于任意給定的生產(chǎn)過程中對數(shù)據(jù)僅限于一個樣本的過程率。另外，隨著η2 增加（也就是，空切功率占總功率的很大一部分）e2比e 1 小的概率也隨之增加。請注意,這兩個常數(shù)小于平均數(shù)。像之前提到的一樣，平均電能消耗量由切削電能消耗P cut和空切P air兩個部分組成。這說明，由于負(fù)荷的增加，有效的減少了加工時間，從而控制了電量的消耗。為了保證切削力相同。其中3號刀具的切削功率最大，但是主軸電機(jī)和主軸驅(qū)動器上的負(fù)載卻比用2號刀具在其余條件同等，將進(jìn)給速率調(diào)大兩倍或更大的倍率還要大。由于機(jī)床的空切功率為1510W，增加了材料去除率后的能量消耗也只是增加了28%而已。經(jīng)測量刀具2所用的切削參數(shù)的平均空切切削功率為1510W，所以這是要從總的切削功率中減去的。表1總結(jié)了切割條件使用。2. 兩齒的錫涂層的硬質(zhì)合金立銑刀。當(dāng)工藝參數(shù)的選擇原理推薦條件時，刀具磨損和刀具成本顯著增加。有關(guān)參數(shù)對材料去除率(.)在日本森精機(jī)NV1500不同而選擇合適的常規(guī)工具。由于發(fā)現(xiàn)提高進(jìn)階速率對刀具的壽命有可怕的后果，所以本實驗通過改變竊謔寬度和切削深度來改變材料去除率，來分析材料去除率對切削功率的影響，更重要的是對能耗的影響。研究發(fā)現(xiàn)，高皮重機(jī)床的能耗主要依賴于處理時間方面，受制于部分幾何、工具的路徑、和材料去除率。 負(fù)荷切削剖面正如迪亞茲在參考文獻(xiàn)[3]里所描述的那樣，一臺機(jī)床的能耗由切削能耗、變量能耗、恒定能耗元件的能耗組成。生命周期評估的缺點是這一方法需要獲取過程細(xì)節(jié)的數(shù)據(jù)，這是一個耗時而且資源密集型的方法。機(jī)床就是這樣的一個產(chǎn)品。因此，為了研究切削鋼件的能耗情況，本次研究通過研究了機(jī)床切割鋁和聚碳酸酯的工件所需要消耗的功率進(jìn)來進(jìn)行了比較。迪亞茲，艾琳娜一臺微細(xì)加工中心在不同的材料去除率下切削低碳鋼所消耗的功率是通過機(jī)床的比能來確定的。 Liow, .。 Schlosser, R. (2009): Strategies for Minimum Energy Operation for Precision Machining, in: Proceedings of the Machine Tool Technologies Research Foundation (MTTRF2009) 2009 Annual Meeting, pp. 4750, Shanghai, China. [6] Inamasu, Y.。 Jarvis, A.。 Pavanaskar, S.。 Chen, Y.。 Horvath, A.。 consequently the energy consumption can be expanded as follows: (1)Two scenarios 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,αandβ, 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. (2) (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. (4)If the relative size of the air cutting power demand is denoted by: (5)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). (6)So if β is less than α, then e2 will always be less than e1. Also, asη2 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: (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 mm?3/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 cm?3/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 mm?3/s would show only a minor decrease in energy consumption given s