Modelling of energy demand from computer numerical control (CNC) toolpaths

Abstract

It is important to accurately model the total electrical energy requirements in order to compare and select the least energy consumption toolpath in a manufacturing process. To enable this goal in this study, a feed axes energy demand model (which incorporates the weights of feed axes, machine vice, and workpiece) proposed in previous work by the authors was integrated and used to refine the energy consumption models for machine tools to analytically estimate the power and processing time, and hence energy required to execute a CNC toolpath. Furthermore, an algorithm for establishing energy prediction software with regards to numerical control (NC) codes was developed based on the proposed energy consumption model. The NC-code based analytical model and energy prediction software were both validated by undertaking slot milling of a 2D half bottle toolpath. Results show that shorter linear path lengths (i.e. G01) and circular path segments (i.e. G02 and G03 codes) were highly energy intensive. This is because for short length segments, the maximum feedrate may not be reached due to constraints imposed by acceleration and deceleration; the weights carried take a higher share of the load, and therefore increase the inertia effects on the drive. Thus, energy intensity in machining could be significantly reduced by selecting toolpaths with longer linear path segments. The knowledge obtained in this study would enable machining engineers to predict the electrical energy for toolpaths and hence enable selection of toolpaths for reduction of electrical energy demand in machining.

Selection of Parameters and Strategies to Reduce Energy Consumption and Improve Surface Quality in EN-AW 7075 Molds Machining

“…The measurements for surface roughness, Ra (µm), at the base (B) and walls (W) of the molds and the EEC (kJ) [21,24] corresponding to each of the 32 tests undertaken are shown in Table 3. This table also shows the active electrical energy consumed by the machining center during each cycle of milling.…”

“…Priarone [20] has evaluated the electrical consumption of a shaping grinding process for different process parameters via a full factorial experimental plan. Eden and Mativenga [21] have quantified the electrical consumption of a milling machine for different linear paths (G1) and circular paths (G2 and G3) in order to predict the electric demand of the machine during the execution of a NC program. Guerra-Zubiaga et al [22] have studied different cutting trajectories and cutting parameters (feed rate, spindle speed, and depth of cut) in a slot milling process to analyze its influence on electrical consumption of the machining center.…”

Erratum to: Toolpath strategies and management to optimize energy consumption on 3-axis CNC milling machine

“…The Graphic User Interface (GUI), inspired by Edem and Mativenga's work [9], as seen in Fig. 3, is developed to assist the estimation of the energy consumption.…”

“…Energy consumption on the spindle motor and each axis feed motor is then processed using a Graphical User Interface, by computing the energy consumption as a summation of the energy on all the lines of the NC code. Previously, other researchers have developed energy model and energy prediction software to analytically estimate the power consumption and the processing time [9]. This research was used to develop an NC code-based software to predict the lowest energy consumption in machining a certain workpiece.…”

Energy consumption modelling in milling of variable curved geometry

“…Edem and Mativenga [11] focused on an improved prediction model of energy requirements by incorporating weight factor of feed drive. In their work, it is concluded that toolpath with longer linear path segments should be selected to reduce energy demand in machining.…”