Key Engineering Materials Vol. 814

Abstract: Based on orthogonal experiments, the influences of grinding process parameters including depth of cut (a_p), workpiece infeed velocity (v_w) and transverse regrinding value (C_r) on hardened layer depth (HLD) of 40Cr steel are studied in the grind-hardening process. The grind-hardening orthogonal experiments of 3-factors are performed on the 40Cr steel with the L₁₆ (4⁵) orthogonal table and the experimental optimization design theory. To understand quantitatively the effects of three grinding process parameters, the experimental data are modeled by regression. Among three grinding process parameters, the most important parameter is a_p, followed by v_w and C_r respectively. The experimental results indicate that HLD would increase with the increasing of the depth of cut and the decreasing of the workpiece infeed velocity in grind-hardening process, but HLD would decrease with the increasing of the interaction between the depth of cut and workpiece infeed velocity.

Abstract: Semiconductor manufacturing management system was developed and grown up over the past decades. In order to increase the product yield and enhance the production productivity, cluster tools became the main stream in modern wafer fabrication factories which occupies over 50% of production equipment. Generally, cluster tools are integrated by several components including robots, vacuum chambers (Load locks) and single-wafer process chambers in a module and can be treated as a small factory. The throughput estimation before recipe release is very difficult. However, it is necessary and important for the planning activity. In this work, a throughput estimation model for cluster tools is proposed. The Multiple Regression Analysis is applied to develop a set of throughput estimation equations. A simulation model of cluster equipment including 3 single-wafer process chambers are built to get the historical throughput data for the regression analysis. From the Multiple Regression Analysis, it reveals that different numbers of recipes processed in the same time have to develop different regression model. The major factors in the regression model include numbers of load ports and process time of each recipe. Furthermore, a set of recipes are used to test the accuracy of estimation. Based on the testing results, they revealed that the MAPE is under 3% and the estimation model is accepted in practice to forecast the throughput of recipes for the planning activities.

Abstract: This study proposes an intelligent optimization system based on the Taguchi method, back-propagation neural network (BPNN), multilayer perceptron (MLP) and modified PSO-GA to find optimal process parameters in plastic injection molding (PIM). Firstly, the Taguchi method is used to determine the initial combination of parameter settings by calculating the signal-to-noise (S/N) ratios from the experimental data. Significant factors are determined using analysis of variance (ANOVA). The S/N ratio predictors (BPNN_S/N) and quality predictors (BPNN_Q) are constructed using BPNN with the experimental data. In addition, a modified PSO-GA algorithm in conjunction with MLP is used to find initial weights of BPNN and to reduce the training time of BPNN. In the first stage optimization, the S/N ratio predictors are coupled with GA to reduce the variations of the manufacturing process. In the second stage optimization, The combination of S/N ratio predictors and quality predictors with modified PSO-GA is empoyed to search for the optimal parameters. Finally, three confirmation experiments are performed to assess the effectiveness of these approaches. The experimental results show that the proposed system can create the best performance, and optimal process parameter settings which not only enhance the stability in the whole injection molding process but also effectively improve the PIM product quality. Furthermore, experiences of the novel hybrid optimization system can be transferred into the intelligent PIM machines for the coming up internet of things (IoT) and big data environment.

Abstract: Based on the fundamental theory of axial vibration drilling, the influence of vibration drilling on the feed-exit burr has been analyzed. The result shows that, due to axial vibration,vibration drilling has some unique characteristics, such as variable-thickness cutting and impulse cutting,which not only improve the chip-breaking conditions and working angle of the drill,but reduce the thrust force.Therefore, the plastic deformation of workpiece material and the exit burr are restrained and decreased effectively.

Abstract: With the development of high-speed machining technology, new technical requirements have been put forward for the clamping of high-speed cutting tools. The traditional clamping methods can not meet the needs of high-speed machining. In this paper, the comprehensive performance of high-speed chucks is systematically compared and analyzed, and the characteristics and main application areas of various high-speed chucks are sorted out, which provides a theoretical basis for scientific and rational selection of chucks.

Abstract: Additive manufacturing (AM) methods are developing and have become popular, but questions remain about the strength of parts made by this method. We have already investigated the effect of the lamination direction on the fractures in bearing specimens. In this study, we made inner defects in the 3D-printed bearing specimens and performed rolling contact fatigue (RCF) tests on this specimens immersed in a water bath in order to investigate the fracture of 3D printed bearings.

Abstract: Welded arc welding repair welding technology was used to repair the casting defects of high chromium cast iron ball mill liners. Select the same high-chromium cast iron as the casting. The diameter of the electrode is 4mm and the welding current is 150-160A. After welding, the castings were found to have no cracks by surface non-destructive testing. The macro-hardness was comparable to that of the matrix material, and the microstructure showed that the fused surface was a good metallurgical bond.

Abstract: The single-sided welding double-sided forming technology of electrode arc welding is the operation technology that must be mastered in the qualification of welders. The welding of the bottom layer is the key. In this paper, the influence of factors such as plate assembly size, process parameters and operation mode on welding quality is analyzed by welding test method, and the best welding process and operation technology are determined, which provides guarantee for welding training.

Abstract: In order to determine the weldability of a new type of low alloy high strength steel, the feasibility of the proposed welding process was examined and the welding procedure qualification of a new type of ultrahigh strength steel WELDOX 1100 was carried out through the weldability test of the welded joint, the small iron research and the highest hardness test. . The test result satisfies the specification requirements and proves that the proposed welding process plan is correct and feasible. It provides a reliable basis for the preparation of welding process documents and ensures the smooth development of the company's new products.

Abstract: WELDOX series steels are commonly used structural steels. The effects of welding voltage, welding current and arc height on penetration and weld width of WELDOX960 steel sheet were studied. The mechanical properties and microstructure of WELDOX960E high strength steel welded joints were study by tensile, bending, impact, hardness and metallographic analysis.