Experimental Optimization of Process Parameters in CuNi18Zn20 Micromachining

Ultraprecision micromachining is a technology suitable to fabricate miniaturized and complicated 3-dimensional microstructures and micromechanisms. High geometrical precision and elevated surface finishing are both key requirements in several manufacturing sectors. Electronics, biomedicals, optics and watchmaking industries are some of the fields where micromachining finds applications. In the last years, the integration between product functions, the miniaturization of the features and the increasing of geometrical complexity are trends which are shared by all the cited industrial sectors. These tendencies implicate higher requirements and stricter geometrical and dimensional tolerances in machining. From this perspective, the optimization of the micromachining process parameters assumes a crucial role in order to increase the efficiency and effectiveness of the process. An interesting example is offered by the high-end horology field. The optimization of micro machining is indispensable to achieve excellent surface finishing combined with high precision. The cost-saving objective can be pursued by limiting manual post-finishing and by complying the very strict quality standards directly in micromachining. A micro-machining optimization technique is presented in this a paper. The procedure was applied to manufacturing of main-plates and bridges of a wristwatch movement. Cutting speed, feed rate and depth of cut were varied in an experimental factorial plan in order to investigate their correlation with some fundamental properties of the machined features. The dimensions, the geometry and the surface finishing of holes, pins and pockets were evaluated as results of the micromachining optimization. The identified correlations allow to manufacture a wristwatch movement in conformity with the required technical characteristics and by considering the cost and time constraints.

Control Algorithm of Precision Machining

Due to more and more private customized non-standard design and precision manufacturing, as well as strict requirements for green environmental protection and sustainable economic development mode, it is challenging to realize the synchronous meeting of energy-saving optimization requirements in the processing process of high-precision workpiece. A new semi-automatic machining optimization system is proposed in this paper. The system is based on the high-precision 3D computer files of the workpiece to be processed and the laser thermophysical system. At the same time, the processing parameters are optimized based on the high-precision algorithm. The innovative contents of the high-precision optimization system include: (1) reciprocating fast high-frequency program design. Its single cycle task is: "core data acquisition, data in-depth analysis / machining precision refinement, key machining parameters recalibration", in order to maximize the process adaptability of the optimization system designed in this study in the highprecision machining process of different types of workpieces. (2) A new green energy-saving and environmental protection model, using primary chemical degreasing and laser derusting processing to get the most accurate 3D scanning files of parts waiting for processing, minimize the process error, so as to maximize the material and energy efficiency. In the calculation of the energy model, the most scientific consumption of coolant is considered.

Reduction of Power Consumption by Chip Breakability Control in Ti6Al4V Titanium Alloy Turning

The paper concerns the problem of energy savings in turning of titanium alloy Ti6Al4V. Since this alloy belongs to difficult to cut materials, there is a problem with chip forming and breaking. The turning process is often supported by implementing a high-pressure cooling (HPC) system. Based on the observations and the adopted chip classification method, the authors proved that it is not necessary to use this method in roughing operations, however it helps with the chips breaking process in finishing operations. A general algorithm for machining optimization due to the chip geometry is presented and described. In the presented case, it was shown that the acceptable chip geometry could be obtained with a reduced power consumption by approximately Pc = 0.5 kW. The authors concluded that it was not necessary to apply cutting data and a coolant system to achieve perfect chip geometry. An acceptable form was often sufficient, while requiring less energy. An additional factor resulting from the operation of systems supporting the cutting process, such as an HPC device, should be taken into account in the formula concerning the energy consumption (EC) of a computerized numerical control (CNC) machine tool.