# Energy Consumption Model for Drilling Processes Based on Cutting Force
## 1 Introduction  
In recent years, with the intense discussion of a low-carbon economy [1] and carbon trading [2], energy issues have once again caused widespread concern [3]. As energy prices continue to rise, the manufacturing industry, which is the largest energy consumer industry, is paying more and more attention to energy consumption in the manufacturing process, and reducing energy consumption has become a goal pursued by the manufacturing industry. In particular, drilling is widely used in the aerospace manufacturing process [4]. Studies have shown that, during the manufacture of a medium-sized aircraft, more than 6500 holes need to be machined, most of which are drilled [5]. At the same time, drilling is the main processing technology for the roughing and semi-finishing of holes; however, the processing efficiency is relatively low which leads to huge levels of energy consumption during processing [6]. Therefore, finding a solution to the problem of reducing energy consumption and increasing energy utilization during drilling processes is worth studying. To obtain a high utilization of energy in manufacturing processes, the first step is to understand and characterize how energy is consumed in manufacturing [7]. Recently, a number of energy consumption models have been proposed, particularly for machining. These existing models can be broadly classified into two categories: material removal rate (MRR)-based and detailed parameter (DPT)-based models [8]. The MRR-based models predict total energy consumption based on the assumption that the total energy assumption and MRR are linearly related. [PERSON] et al. [9] pioneered the idea that machiningenergy consumption is related to the MRR. [PERSON] and [PERSON] [10] proposed a specific energy consumption model, which proved to be of high accuracy for both lathes and milling machines. [PERSON] et al. [11] improved the MMR-based energy consumption model by considering the effects of no-load conditions and spindle speed on energy consumption. [PERSON] et al. [12] studied how to obtain the minimum roughness and maximum material removal rate. [PERSON] et al. [13] proposed a decision rule for minimum energy consumption during turning based on the material removal rate. Differently from MRR-based models, DPT-based models calculate the total energy consumption by using different parameters which are obtained based on different theories. Many studies have pointed out that the cutting parameters are the major factors affecting energy consumption. [PERSON] et al. [14] proposed an approach which combines energy consumption with surface roughness and applied it to finish turning; [PERSON] et al. [15] proposed a tool path planning algorithm for five-axis milling with the goal of minimizing energy consumption. However, the accuracy of their model was found to be less than satisfactory in some cases. Some energy models are based on cutting forces including the work of [PERSON] et al. [16] and [PERSON] and [PERSON] [17] who noted that the transformation of the cutting force caused by the tool edge geometry directly affects specific energy consumption (SEC). Research by [PERSON] and [PERSON] [18] suggests that energy consumption models based solely on cutting forces only reflect the minimal energy consumption and not the maximum energy demand. To further improve the above energy models, [PERSON] et al. [19] proposed a method based on the cutting force to establish an energy consumption model for the milling. [PERSON] et al. [20] improved the energy consumption model of [PERSON] [19] by introducing no-load power to establish a milling energy consumption model and a milling energy consumption model considering tool wear [21]. As already alluded to, although many of these existing energy models are comprehensive and detailed, most of the above energy models, whether MRR- or DPT-based, are built for turning or milling. There are very few studies on energy consumption for drilling. However, drilling is widely used in aerospace manufacturing processes [22].