Papers by Keyword: Burr

Abstract: This paper reports a study of a micro-EDM process to fabricate micro-through holes in 30 micron thick copper sheets. Circular holes in various micro-sizes were produced by a micro-EDM machine and with tungsten electrodes. Scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDX) were used to identify the influence of electric sparks on the quality of the fabricated features by careful study of resulted cavitation, adhesion of debris, and re-solidification of molten materials, etc. Such analyses allow the generalization of the relevant fabrication mechanisms. In addition, measurements of overcut of the holes facilitate a working model to be developed for predicting the overcut as a function of process parameters including the discharge capacitance and the working voltage of the circuitry. Results of this study enable the derivation of proper settings for fabricating holes of good quality and permit the precision fabrication of the range of micro-throughholes.

Abstract: Microcosmic and macroscopic form of CFRP holes drilled by new PCD tool were observed in this paper. Location and distribution of burr and fiber direction of burr were analyzed, and formation mechanism of burr of CFRP hole exit is studied tentatively. The methods of inhibit the formation of burr formation were put forward from the design principles of the tool geometry parameters.

Abstract: Micro-milling is widely used in material removal processes in industry. However, burrs are often formed on workpiece edges in milling process. Burr effects the dimensional tolerance and performance of the workpiece seriously and is desirable to be controlled. Burrs prediction technology is useful for cutting conditions optimization to control burrs forming. Due to lots of factors influencing the formation process of burr, it is a difficult task to establish the burr size prediction model by mathematical and mechanical method. RBF neural network was used for burr formation predition. Design of the network, network structure parameters determination and generalization capability of the network were analyzed and discussed. Achieved network has good fitting performance and generalization capability validated by experiments.

Abstract: Burrs and fractures are two types of shapes formed on exit edges in pricision machining. They affect the quality of workpiece and the efficiency of prodcution seriously. A finite element model of fracture formation process to simulate the machining process of 2024-T3 Aluminum alloy is proposed. According to simulation results, five stages and variation of shear shain in fracture formation process are analyzed. It is found that shear strain plays an important role in fracture forming process. The method of determination of critical shear strain for fracture forming is proposed from simulation results.

Abstract: Burr formation is a bottleneck of the production line and deteriorates the automation integrity. To this question, investigations were carried out in this paper on the burr formation in milling aluminum alloy (Al-alloy), in order to enhance productivity and workpiece quality by active process control. Milling burr formation were predicted and minimized for the sake of rough machining and finishing operation, using strategies of tool path planning, processing parameter optimization as well as workpiece rigidity strengthening. The conclusions reached in this paper are useful in practice to realize burr-free Al-alloy milling for manufacturing automation.

Abstract: Burrs are unwanted materials remaining not only after the machining operation but also after the sheet metal cutting operation. Burr formations decrease the part accuracy and increase the cost for the deburring operation. In this study, the reciprocating shaving process was proposed to eliminate crack and burr formations in the pressed parts. The finite element method (FEM) was used as a tool to investigate the possibility of this process and its working process parameters as well. The FEM simulation results showed the effects of clearance in shearing operation, shaving allowance, and half-shaving direction on the shaved surface. These results were validated by laboratory experiments, and they showed a good agreement with each other. The FEM simulation could be used as a tool for prediction of the cut surface in the reciprocating shaving process. The results revealed that the reciprocating shaving process could be applied for eliminating crack and burr formations in pressed parts using suitable working process parameters.

Abstract: There is an increasing demand for high quality metal stamped parts. In general, burr formation is the main defect found subsequent to the blanking process. This defect must be strictly removed specifically for consumer products in order to prevent any kind of injury to the operators. Such a removal process results in an increase of the production cost. The unique merit of the counter-blanking process focuses on fabricating the burr-free blanked parts. However, it is difficult to control the numerous process parameters involved in this process in order to achieve the burr-free blanked parts. Thus, this study aims at investigating the process parameter design for the counter-blanking process by means of combining the finite element method (FEM) and statistical analysis techniques, including the Taguchi method and the analysis of variance (ANOVA) techniques. The results indicate that the process parameter of blanking clearance has a major influence on the die-roll formation features of the burr-free blanked part, respectively followed by the punch penetration depth and the same level of influence of the two process parameters of punch and die diameters in the second step. To conclude, this technique could be applied as a tool to achieve good quality of the burr-free blanked parts by optimizing the value of the process parameters and their favorable combinations.

Abstract: The objective of this research was to study and improve the destructive 3D digitizer based on grinding technique that was developed previously. It is shown that the grinding technique used in the 3D digitizer generates better surface condition than the milling technique commonly used in other 3D digitizers, and this is beneficial to the subsequent image processing to obtain the profiles of the cross-sectional images. To increase the overall image resolution, an image-merging method was employed by putting a fiducial on top of the object to allow us to merge partial images into a full image. One of the key factors for the success of image processing is to have good contrast between the object and the background material, and we developed a program with a controllable power supply to automatically adjust the illumination based on the histograms of the images to obtain the maximum contrast. At the end, we performed an experiment by using Taguchi method and found out that the grinding depth is the most significant factor that can be controlled on the destructive 3D digitizer for burr length reduction.

Abstract: The dynamics of customer requirements in the global domain are dictating a need for the reconfiguration of existing conventional manufacturing systems in order to adapt and respond to the changing functional requirements. This study presents the investigation of the feasibility of adapting a hydraulic cam system to a power press for uphill sheetmetal piercing. The surface topography of sheared edges of blanks and slugs was analyzed using Zygo New View 200 Scanning White Light Interferometer. The piercing force in each trial was monitored and analyzed via computer-press interface data acquisition system (DAS). The average piercing force, 10721N, obtained was found to be nearly constant throughout the experimental trials.

Abstract: The end surface angle of workpece is one of key factors that affect burr sizes and shapes. In this paper, the burr formation process of different end surface angle is simulated with elastic plastic nonlinear element method based on ABAQUS. The influence of end surface angle of workpiece on burr formation processes in high-speed machining 2024 Aluminum alloy is analyzed. The influence of end surface angle on burr sizes and shapes is studied based on equivalent shear strain and negative shear angle. The results have investigated the mechanisms of burr formation fundamentally, which is the basis of burr minimization.