Jian-wei Ma

Characteristics forecasting of hydraulic valve based on grey correlation and ANFIS

Accurate prediction is crucial for the synthesis characteristics of the hydraulic valve in industrial production. A prediction method (G-ANFIS for short) based on grey correlation and adaptive neuro-fuzzy system (ANFIS) to forecast synthesis characteristics of hydraulic valve is devised and the utilizing of the method can help enterprises to decrease the repair rate and reject rate of the product. Grey correlation model is used first to get the main geometric elements affecting the synthesis characteristics of the hydraulic valve and thus simplifies the system forecasting model. Then use ANFIS to build a prediction model based on the above mentioned main geometric elements. To illustrate the applicability and capability of the devised prediction method, a specific hydraulic valve production was used as a case study. The results demonstrate that the prediction method was applied successfully and could provide high accuracy. The method performed better than artificial neural networks (ANN) to forecast the synthesis characteristics of hydraulic valve.

Hybrid of simulated annealing and SVM for hydraulic valve characteristics prediction

Accurate prediction for the synthesis characteristics of hydraulic valve in industrial production plays an important role in decreasing the repair rate and the reject rate of the product. Recently, Support Vector Machine (SVM) as a highly effective mean of system modeling has been widely used for predicting. However, the important problem is how to choose the reasonable input parameters for SVM. In this paper, a hybrid prediction method (SA-SVM for short) is proposed by using simulated annealing (SA) and SVM to predict synthesis characteristics of the hydraulic valve, where SA is used to optimize the input parameters of SVM based prediction model. To validate the proposed prediction method, a specific hydraulic valve production is selected as a case study. The prediction results show that the proposed prediction method is applicable to forecast the synthesis characteristics of hydraulic valve and with higher accuracy. Comparing with Adaptive Neuro-Fuzzy Inference System (ANFIS) and Artificial Neural Networks (ANN) are also made.

Spindle Speed Selection for High-Speed Milling of Titanium Alloy Curved Surface

The development of high-speed milling technology provides an effective processing method for titanium alloy curved surface with high quality, and the spindle speed is an important machining parameter for the high-speed milling of titanium alloy curved surface. The variation of the geometric features of the titanium alloy curved surface results in the sharp fluctuation of the cutting force as well as the vibration of machine tool, which not only makes a severe impact on the surface machining quality and the tool life but also greatly affects the efficiency of the high-speed milling. An experimental study is carried out to determine the spindle speed for high-speed milling of the titanium alloy curved surface based on the cutting force. The experimental results indicate that in high-speed milling process, the cutting force is associated with the geometric feature of the curved surface and the change of cutting force is relatively smooth when the spindle speed is in the range from 9000 to 13,000 rpm for the machining of titanium alloy curved surface.

Pre-compensation for continuous-path running trajectory error in high-speed machining of parts with varied curvature features

Parts with varied curvature features play increasingly critical roles in engineering, and are often machined under high-speed continuous-path running mode to ensure the machining efficiency. However, the continuous-path running trajectory error is significant during high-feed-speed machining, which seriously restricts the machining precision for such parts with varied curvature features. In order to reduce the continuous-path running trajectory error without sacrificing the machining efficiency, a pre-compensation method for the trajectory error is proposed. Based on the formation mechanism of the continuous-path running trajectory error analyzed, this error is estimated in advance by approximating the desired toolpath with spline curves. Then, an iterative error pre-compensation method is presented. By machining with the regenerated toolpath after pre-compensation instead of the uncompensated toolpath, the continuous-path running trajectory error can be effectively decreased without the reduction of the feed speed. To demonstrate the feasibility of the proposed pre-compensation method, a heart curve toolpath that possesses varied curvature features is employed. Experimental results indicate that compared with the uncompensated processing trajectory, the maximum and average machining errors for the pre-compensated processing trajectory are reduced by 67.19% and 82.30%, respectively. An easy to implement solution for high efficiency and high precision machining of the parts with varied curvature features is provided.

Using support vector machine for characteristics prediction of hydraulic valve

Accurate prediction for the synthesis characteristics of a hydraulic valve plays an important role in decreasing the repair and reject rate of the hydraulic product. Recently, intelligence system approaches such as Artificial Neural Network (ANN) and neuro-fuzzy methods have been used successfully for system modelling. The major shortcomings of these approaches are that a large number of training data sets are needed or the training time is too long. Using Support Vector Machine (SVM) approaches would help to overcome these issues. In this study, the SVM approach was used to construct a hydraulic valve characteristics forecasting system. To illustrate the applicability and capability of the SVM, a specific hydraulic valve production was selected as a case study. The prediction results showed that the proposed prediction method was more applicable and has higher accuracy than adaptive neuro-fuzzy inference system (ANFIS) and ANN in predicting the synthesis characteristics of hydraulic valve.

Influence of spindle speed on tool wear in high-speed milling of Inconel 718 curved surface parts:

High-speed milling, which provides an efficient approach for high-quality machining, is widely adopted for machining difficult-to-machine materials such as Inconel 718. For high-speed milling of Inconel 718 curved surface parts, the spindle speed which determines cutting speed directly is regarded as an important cutting parameter related to tool wear and machining efficiency. Meanwhile, because of the changing geometric features of curved surface, cutting force is changing all the time with the variation of geometric features, which influences not only tool wear but also machining quality significantly. In this study, the influence of spindle speed on coated tool wear in high-speed milling of Inconel 718 curved surface parts is studied through a series of experiments on considering tool life, cutting force, cutting force fluctuation, and machining efficiency. According to the experimental results, the appropriate spindle speed that can balance both the tool life and the machining efficiency is selected as 10,000 r/min for high-speed milling of Inconel 718 curved surface parts. In addition, the coated tool wear mechanism is investigated through scanning electron microscopy–energy dispersive x-ray spectroscopy analysis. The results show that at the beginning wear stage and the stable wear stage, the coated tool wear is mainly caused by mechanical wear. Then, with the increasing cutting temperature due to the blunt tool edge, the tool wear becomes compound wear which contains more than one wear form so as to cause a severe tool wear.

Influence of cutting tool geometrical parameters on tool wear in high-speed milling of Inconel 718 curved surface

High-speed machining provides an efficient approach for machining Inconel 718 with high quality and high efficiency. For high-speed milling of Inconel 718 curved surface, the geometrical characteristics are changing continuously leading to a sharp fluctuation of cutting force, which will aggravate the tool wear. As the wear mechanism of coated cutting tool is seriously affected by the cutting tool geometrical parameters, suitable geometrical parameters of cutting tool should be selected to avoid the cutting tool from being worn out very quickly. In this study, the influence of cutting tool geometrical parameters on tool wear in high-speed milling of Inconel 718 curved surface is investigated with coated cutting tool, and the cutting force in milling process is also analyzed. The results show that the cutting force variation can manifest the tool wear degree, and the failure type of coated cutting tool in plane milling and curved surface milling after the same cutting length is different. Furthermore, the cutting tool geometrical parameters seriously affect the tool wear and the tool life in high-speed milling of Inconel 718 curved surface. Concretely, the small rake angle has greater strength and has superiority, the relief angle increasing can enhance the tool life, and the tool life is decreased with the increasing of helix angle for the cutting tool, whose helix angle is larger than 30°. This study provides a theoretical basis for cutting tool wear mechanism and cutting tool geometrical parameter selection in high-speed milling of Inconel 718 curved surface, so as to guarantee the machining efficiency in high-speed milling of Inconel 718 curved surface.

Burr Control for Removal of Metal Coating from Plastics Substrate by Micro-Milling

Manufacturing of miniaturized circuits on the surface of plastic substrate plays an important role for the industrial application. Many of these kinds of parts cannot be fabricated by conventional processing methods due to the manufacturing requirements are improved continuously and the plastic substrate presents 3D structure. Since the superior advantages of the micro-milling, graphically removal of metal coating from plastic substrate by micro-milling has led the way in manufacturing of high-accuracy circuits. In order to improve the edge quality of the circuits, the effect of processing parameters on burr sizes is quantitatively analyzed and a control model of burr formation is established based on the experiments. Furthermore, aiming at the problem that surface of the polyimide (PI) substrate often shows free-form state due to the machining error, the technology that removal of constant material from free-form substrate surface is proposed. With the optimized parameters and compensation technology of milling depth, a typical antenna circuit is machined via micro-milling at last. The experimental results indicate that the edge of the pattern is smooth, and there are almost no burrs. The achievements in this study could be applicable to industrial production.

Machining Parameter Optimization in High-Speed Milling for Inconel 718 Curved Surface

Machining technology for nickel-based alloy Inconel 718 is a hotspot and difficult problem in industrial fields and the high-speed milling (HSM) shows obvious superiority in difficult-to-process material machining. As the machining parameters are crucial in processing of Inconel 718 and the study of chip is important in metal cutting, there is an urgent need for deep research into the machining parameter optimization based on chip variation in HSM for Inconel 718 curved surface, so as to further increase the productivity of Inconel 718 in aerospace field. Regarding Inconel 718 curved surface, an experimental study about the machining parameter optimization based on chip variation in HSM is conducted. The relationship between chip shape and machining parameters is studied, and the roughness is measured and discussed for the machined curved surface. Results indicate that the chip area relates to geometric feature of curved surface, the optimal range for spindle speed is from 9000 to 11000 rpm based on chip variation, the feed per tooth should be large in case that condition permitted, and the cutting depth can be selected according to other constraint conditions. This study is significant for improving the machining quality and efficiency of Inconel 718 curved surface.

Nanosecond pulsed laser processing circuits on the copper clad polyimide

Precision processing of miniaturised circuits on the surface of three-dimensional (3-D) structure is of great importance for the telecommunication equipment. Laser micro-machining technologies have led the way in the development of innovative solutions in manufacturing high-accuracy circuits. In this paper, fine strip-line of planar helical antenna on the copper clad polyimide (CCPI) is fabricated based on the application of nanosecond pulse laser. In order to obtain the optimised processing parameters for planar helical antenna, ablation experiments of single grooves are performed and the effect of process parameters, such as laser wavelength, single pulse energy density, repetition frequency, scanning speed, laser spot overlap coefficient and milling times, are quantitively analysed. And the strip-line of planar helical antenna is processed under the optimised condition (laser single pulse energy density is 25 J/cm2, frequency is 30 kHz, laser spot overlap coefficient is 0.9, and milling times is 1). Experimental results indicate that the minimum width of micro-strip can reach 50 μm, and form error of strip-line edge processed by nanosecond pulse laser is less than ±10 μm, which could match the geometric accuracy requirement of the micro-strip antenna.