With the in-depth integration of intelligent manufacturing and energy-efficient manufacturing, energy consumption should be taken as an important indicator to meet the development philosophy of ...low-carbon manufacturing while continuously pursuing manufacturing efficiency. The intelligent estimation of energy consumption for machined parts is the basis for establishing an energy-efficient intelligent manufacturing system. STEP-NC is one of the practical schemas to implement an intelligent manufacturing mode in the CNC machining field. Hence, this paper proposed an estimation methodology of energy consumption based on the STEP-NC program to realize the estimation of the staged and overall energy consumption for parts. Firstly, the influencing factors of energy consumption are analyzed in detail and the data model of energy consumption is extended to the STEP-NC standard accordingly. Secondly, the energy consumption estimation methodology based on the machining feature was constructed, and the mapping relationship between STEP-NC program and the estimation method was established. Finally, the energy consumption estimation framework with the STEP-NC program as input is developed while the validity of the methodology is verified by practical machining experiments. By comprehensive analysis, the methodology shows promising results in efficiency and application prospect, which lays a foundation for further intelligent energy-efficient research.
This study presents an approach for determining energy efficient toolpaths using numerical control (NC)-based energy demand software. To achieve this, NC programmes were generated for the true ...spiral, rectangular spiral, and square contour toolpaths from HyperMill, a commercially available Computer-Aided Manufacturing (CAM) software for performing pocket milling of AISI 1018 steel on a 3-axis CNC milling machine. These programmes were uploaded as input on the graphical user interface (GUI) of the NC code-based energy demand software. The result obtained from NC code-based energy software was validated against the theoretical total energy and processing time, and the pocket milling of AISI 1018 steel on a 3-axis CNC milling machine. The theoretical, software, and experimental analyses show that the true spiral toolpath had the lowest total electrical energy demand and processing time. The result also shows that the energy demand software could be adopted to accurately predict the total electrical energy and processing time pre-machining. This could save setting up and trial by error practices and costs. Further studies included surface roughness analyses of the machined pockets after milling, and an improved surface finish of the pocket was obtained with the true spiral toolpath when compared with the other considered toolpaths. Therefore, for energy efficient machining, it is recommended that NC code-based energy demand software which incorporates the weights of feed axes, vice, and workpiece, as well as the power required by the feed drive during cutting should be adopted for the accurate prediction of total electrical energy demand and total processing time of a machining process.
This study proposes a method for extracting the machining region machined by swarf machining and hole drilling from a Standard Triangulated Language (STL) data exported from 3D CAD and automatically ...generating a tool path. First, a method is proposed for extracting the machining region and obtaining geometric features, such as slope, curved surfaces, holes, and pockets, from the STL data exported from 3D CAD. The STL data uses only triangular mesh data and drops all information, which is necessary for extracting the removal volume for the machining and geometrical characteristics. Then, a half-edge algorithm is proposed that clarifies the connection relationship between planes by integrating triangular meshes of the same plane in a model in STL data and realizes automatic extraction of machining regions through the analysis of shape data. Subsequently, a method is proposed to determine the 5-axis indexing posture and generate a tool path according to the geometrical features of the machining region. A machining experiment was conducted to validate the effectiveness of the proposed method. As a result of the machining experiment, it was confirmed that the tool path automatically generated from the STL data exported from 3D CAD can be machined without any problems and with a practical level of accuracy.
•A multi-granularity NC program optimization approach for energy efficient machining which includes the granularity of a group of NC programs for a setup and the granularity of a NC program.•On the ...first level of granularity, the execution sequence of the NC programs for the setup of a part is optimized to reduce the energy consumed by the cutting tool change among the NC programs.•On the second level of granularity, the execution sequence of the features in the same NC program is optimized to reduce the energy consumed by the cutting tool's traveling among the machining features.•Experiments on the practical cases show that the optimization results are promising and the approach has significant potential of applicability in practice.
NC programs are widely developed and applied to various machining processes. However, the lack of effective NC program optimization strategy for the machining energy efficiency has been crippling the implementation of sustainability in companies. To address this issue, a multi-granularity NC program optimization approach for energy efficient machining has been developed and presented in this paper. This approach consists of two levels of granularities: the granularity of a group of NC programs for a setup where the features are machined on a single CNC machine with the same fixture and the granularity of a NC program. On the former level of granularity, the execution sequence of the NC programs for the setup of a part is optimized to reduce the energy consumed by the cutting tool change among the NC programs. On the latter level of granularity, the execution sequence of the features in the same NC program is optimized to reduce the energy consumed by the cutting tool's traveling among the machining features. Experiments on the practical cases show that the optimization results from this approach are promising and the approach has significant potential of applicability in practice.
At present some CAD/CAM systems allow to create strategies or macros to accelerate the process of creation NC programs. The article deals with the development of experimental strategies in the ...CAD/CAM system. These strategies allow to remove repetitive tasks and allow to accelerate the process of creation the NC programs for machine tools. Feature analysis contained basic types of features and additional attributes of features. This feature analysis is based on possibilities of CAD/CAM system.
In wire electrical discharge machining (WEDM) that can perform 2-D or 2.5-D machining, 3-D complex shape machining is also possible via the addition of a rotary axis on the NC table. Several examples ...of pin-shaped machining using a rotating shaft like spindle have been previously reported. Alternatively, machining using a rotary axis as an indexing device has also been reported. In these machining processes, the rotary axis is not servo controlled. Conversely, a spiral groove is formed on the outer circumference of the round bar by gripping the round bar workpiece on the rotary axis and performing machining in synchronization with the
x
- and rotary axes. In this machining, the gap control in electrical discharge machining is performed along the
x
- and rotary axes. Furthermore, complicated shape machining becomes possible by adding a 2-axis rotary axis of rotation and tilt. When the
x
-axis is synchronized with the rotation and tilt axes, a spiral groove with a variable groove width is formed. In this case, servo control is synchronized with the three axes, and machining proceeds. In this study, we performed spiral groove shape machining through WEDM with the addition of 1-axis or 2-axis rotary axes, consequently verifying the machining accuracy. Moreover, two types of NC program were used for machining, direct input and CAM output, and the accuracy was compared. The results revealed that the groove width was wider in the direct input program. Therefore, there was a possibility that the wire could bend during machining and tilt along the direction of the apparent widening of the groove width. Thus, it is necessary to consider the deflection of the wire in WEDM with a rotary axis, which is different from the conventional one, to realize precision machining.
It has been proved that error compensation is an effective approach to improve machining accuracy of a machine tool cost efficiently. In this paper, the framework of an error compensation software ...system, which can realize software error compensation via numerical control (NC) programs reconstructing, is investigated. And the algorithms relating to error prediction are discussed in detail, such as positioning movement error compensation, linear interpolation movement, and circular interpolation movement error compensation. To realize the error compensation, NC program is reconstructed according to the predicted errors during virtual machining before it is fed to the actual machining. Two controlled machining experiments were carried out. The results show that error compensation methods via reconstructing NC programs can improve the movement accuracy of a computer numerical control CNC machine tool obviously.
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