Advanced Materials Research Vols. 652-654

Abstract: During machining age-hardening aluminum alloy, quench-induced residual stress usually caused serious distortion, which made parts difficult to meet precision requirements. Residual stress patterns through the thickness of 6061T6 aluminum cooling plate were measured by layer removal method. According to residual stress patterns and two parts, four machining strategies were designed and developed by experiment and FEM simulation for investigating the relationship between residual stress and distortion. Distortion increases with increasing stress magnitude, machining depth, and machining asymmetry. Distortion can be minimized effectively by employing appropriate machining strategies which can balance residual stress in parts.

Abstract: Superabrasive grinding wheels are widely applied in today’s grinding industries due to its advantages such as long tool life, low wearing effect, fine dimensional stability etc. Dressing is one of most important processes of grinding operation that largely influences the workpiece quality and manufacturing productivity. However, dressing of superabrasive grinding wheel is low efficiency by conventional dressing method. In this paper, an a flashlamp-pumped pulsed Nd:YAG laser assisted dressing technique for metal-bonded CBN grinding wheel is developed, and experiment results demonstrate the proposed laser-assisted dressing technique is greatly improving dressing efficiency, reducing dressing time, extending the life of diamond dresser comparing to conventional dressing method. Key paramters of straintness, cylindricity and roughness of Crankshaft between before and after dressing operation is contrasted, the results proves that in the practical grinding process, the laser assisted dressing technique has similiar quality in contrast to conventional diamond dressing method and highly promotes the dressing efficiency.

Abstract: Controlling the tooth errors induced by the variation of diameter of grinding wheel is the key problem in the process of ZC1 worm grinding. In this paper, the influence of tooth errors by d1, m and z1 as the grinding wheel diameter changes are analyzed based on the mathematical model of the grinding process. A new mathematical model and truing principle for the grinding wheel of ZC1 worm is presented. The shape grinding wheel truing of ZC1 worm is carried out according to the model. The validity and feasibility of the mathematical model is proved by case studies. The mathematical model presented in this paper provides a new method for reducing the tooth errors of ZC1 worm and it can meet the high-performance and high-precision requirements of ZC1 worm grinding.

Abstract: Abrasive air jet micro-machining is a new promising technology for processing brittle material. An experimental study of micro-channeling on quartz crystals using an abrasive air jet is presented. The effect of the processing parameters on the produced channel profile such as the channel width, depth and kerf taper angle is analyzed, along with the effect on the roughness of channel bottom surfaces. Plausible trends of the major process performance measures with respect to the process parameters have been revealed. These trends are useful in guiding the selection of process parameters in practice.

Abstract: We examined the slicing technique of silicon wafers with little kerf loss using an ultrafine wire tool. As the first step, we performed microgrooving with an ultrafine wire tool. The thinning of the wafer and the decrease in kerf loss can minimize production costs. We discuss the strength characteristics and the microgrooving performance of the ultrafine wire tool. The main results are as follows. The relative velocity greatly affects the grooving properties. The ultrafine wire tool easily breaks when the relative speed is high. When the ultrafine wire tool and abrasives with large diameter grains are used, the ultrafine wire easily breaks and chipping in the work material easily occurs; furthermore, the ultrafine wire strays.

Abstract: According to the characteristics of NM360, a contrast experiment for drilling performance in YG8 cemented carbide twist drill, high-speed steel twist drill and factories used in coating the ordinary high-speed steel twist drill has been done. Using microscope to observe tool wear, we found that the flank wear and chisel edge wear are the main wear of the drill. The carbide tools has a better ability of resistance to plastic deformation, abrasive wear and adhesive wear than high-speed steel cutting tools. The coating tools are better to resist abrasive wear and adhesive wear than uncoated tools.Deformation of carbide cutting tools, abrasive wear, ability than high-speed steel cutting tools.

Abstract: The paper takes the cold working die steel Cr12 for specimen material,carries out the plunge milling test on Cr12 and the plunge milling force has been measured by YDX - Ⅲ 9702 piezoelectric milling dynamometer. The tool deformations are analyzed both in plunge milling and side milling on the same size milling force. Test and analysis show that the axial milling force significantly greater than the other two directions and the tool deformation in plunge milling less than the tool deformation in the side milling.

Abstract: The efficiency of applying 5-axis machining is higher for various products compared to general 3-axis machining, which is restricted to general parts and mold machining. However, impeller machining requires a large tool slenderness ratio to avoid interference with neighboring surfaces. Because such an enlargement of the slenderness ratio causes damage to the tools and deterioration of the quality of products due to the vibration of the tool, it is important to review the cutting characteristics considering the slenderness ratio and to determine the proper cutting conditions. Also, industry has attempted to develop a 5-axis machining automatic CAM module for an impeller that helps inexperienced workers to process the impeller easily by simplifying the process and options for the cutting impeller. The, current status of research on the cutting conditions considering the slenderness ratio to complete a database for a sub-module accounting for the cutting conditions among the components of an automatic CAM module is urgent. Therefore, the purpose of this work is to review the cutting characteristics that influence the cutting of aluminum alloy, the typical material of impeller parts, while also considering slenderness ratio to complete the 5-axis machining automatic CAM module of an impeller and to determine the available cutting area during the roughing and finishing operations.

Abstract: In this paper,we conducted circular cone turning cutting force measurement test by using orthogonal test method and YDCD piezoelectric unidirectional turning dynamometer,then analyzed the orthogonal test results with the intuitive analysis method. A BP neural network model between the cutting speed,feed rate,cutting depth and the main cutting force is established by using Matlab neural network toolbox and then to be verified. The verification results show that the BP neural network circular cone turning cutting force prediction model has very high prediction accuracy.

Abstract: The influence of dielectric jet flushing during Electro Discharge Diamond Surface Grinding (EDDSG) on Ti-6A-4V has been reported in this paper. The metal bonded diamond grinding wheel is used as electrode in Electro Discharge Diamond Surface Grinding process. In this process mechanical grinding is coupled with electrical spark of electrical discharge machine to take up the advantages associated with hybrid machining process. The important input parameters in this investigation were “duty factor”, “wheel speed (rpm)”, “magnitude of current (ampere)” and its “duration (Ton, micro-second)”. The effects of these parameters on outcomes i.e. material removal rate (MRR) and surface roughness (Ra) are measured. The noticeable enhancements in material removal rate and surface finish have been seen during EDDSG of Ti-6Al-4V with effective jet flushing. The performance of EDDSG with jet flushing and without jet flushing has been compared.