A Critical Review on Optimization of WEDM Process Using Taguchi Array

Wire electrical release machining (WEDM) innovation has developed at special case rate since it was first applied over long term prior.WEDM is a widely recognized unconventional material cutting process used to manufacture components with complex shapes and profiles of hard materials. In this thermal erosion process, there is no physical contact between the wire tool and work materials. Wire Electrical Discharge Machining (WEDM) is getting more tasks in fields like dies, punches, aero and many more. It is the very difficult task to get optimum process parameters for higher cutting efficiency. In WEDM process rough machining gives lesser accuracy and finish machining gives fine surface finish, but it reduces the machining speed. This review involves process, principle, literature and applications of WEDM using Taguchi array. Keywords: WEDM; Materials; Machine; Cutting efficiency; Optimization process.

Changes in Residual Stress State During Quench and Temper of Vacuum Carburized Gear Steel

Vacuum carburizing of 9310 gear steel followed by austenitizing, oil quench, cryogenic treatment, and tempering is known to impact residual stress state of the steel. Residual stress magnitude and depth distribution can have adverse effects on part distortion during intermediary and finish machining steps. The present research provides residual stress measurement, microstructural, and mechanical property data for samples taken along a specific heat treat sequence. Test rings of AISI 9310 steel are subjected to a representative gear manufacturing sequence that includes normalizing, rough machining, vacuum carburizing to 0.03”, austenitizing, quench, cryo-treatment, temper, and finish machining. Characterization of a test ring and a metallurgical sample after each manufacturing step allows tracking of residual stress and microstructural changes along the sequence. The results presented here are particularly interesting because the highest compressive residual stresses appear after removal of copper masking, not after quench as expected. Data can be used for future ICME models of the heat treat and subsequent machining steps. Analytical methods include X-Ray Diffraction, optical and electron microscopies, mechanical testing, and hardness testing.

On-Machine Measurement and Error Compensation for 6061 Aluminum Alloy Hexagonal Punch Using a Turn-Milling Machine

For machining parts with complex shapes, consisting of computer numerical control (CNC) machine tools, different CNC machine tools will be used according to the machining method. If the workpiece is removed for off-machine measurement after machining, when the size is incorrect, it will need to be returned to the CNC machine tool for secondary machining. In this case, the workpiece surface quality and machining accuracy will be affected, which is very time-consuming. On-machine measurement and complex machine center is a key to solve this problem. In the recent researches that the touch probe was integrated on three or five axis machine for error compensation and shape construction based on on-machine measurement, but turning-milling machine was rare. In addition, the most types of parts were thin-walled parts or thin web parts. In this study, a contact measurement system is integrated into a CNC combined turning-milling machine for on-machine measuring. Macro-programming is used to design the machining path of A6061-T6 aluminum alloy hexagonal punch, and the action of probe measurement is added to the machining path. As the measured data exceed the tolerance range, the calculated data are fed back to the controller for machining improvement by compensation. The finished hexagonal punch is measured in a 3D coordinate measuring machine and the error is compared. The experimental results show that the contact probe needs to be corrected before machining, and the size of the corrected workpiece can reach the tolerance range of ±0.01 mm. The size error of rough machining is larger than that of fined machining, and the size error of rough machining will increase with the length of the workpiece.

Investigation of ultrasonic-assisted CNC cutting of honeycomb cores

As compared to traditional milling, ultrasonic-assisted cutting of honeycomb core materials has the advantages of small cutting force and superior surface quality. Currently, ultrasonic straight blade V-shaped machining is one of the most efficient roughing processes. The requirement of a processing path to be post-processed based on the processing characteristics of the straight blade cutter is one of the key issues faced while meeting the technological requirements of CNC machine tools for V-shaped machining. A post-processing method of NC code for V-shaped machining of straight blade cutter is proposed in this article. Initially, the V-shaped rough machining process planning is done, followed by the usage of Unigraphics (UG) to output the initial CNC code. Next, the CNC code is executed through the three key technologies of the second arrangement of cutter locations. Later, research is done on information planning of lifting and lowering cutter, along with research on planning of chip breaking toolpath. Eventually, the simulation cutting experiment is carried out through VERICUT. The results demonstrate that the post-processing method can meet the processing requirements.

Prompt Estimation of Die and Mold Machining Time by AI Without NC Program

Machining time estimation is essential for the due-date estimation of products as well as for production planning. Conventionally, machining time has been estimated by a computer aided manufacturing (CAM) system, which requires time and effort to create its numerical control (NC) program and requires machining expertise to operate it. In addition, among the problems with conventional methods, an error in the estimated machining time arises owing to the machine tool’s control characteristics. In this study, an artificial intelligence (AI)-based system capable of estimating machining time promptly and simply based on shape data without requiring any NC program is developed. The input data to the AI system are color information regarding the machined depths, which are used to estimate the rough-machining time, and color information regarding the machined surface curvature distributions to estimate the finish-machining time. Color information on the machined depths and machined surface curvature distributions is created using three-dimensional computer aided design (3D CAD) data. To build the AI system, the shape data and machining time data accumulated at the machining site are used, so that the machining time estimated reflects the machining method, machining expertise, and the machine tool characteristics employed.

Improving the Surface Quality Through a Laser Scan and Machining Strategy Combining Powder Bed Fusion and Machining Processes

This paper focuses on the unconventional laser powder bed fusion (LPBF) technique in which the LPBF and machining processes were executed alternately to fabricate higher quality parts compared to those obtained using subtractive machining processes. The additional machining process changed the stress distribution inside the built part, resulting in the deformation of the surface morphology in the final part. The phenomenon pertaining to the combined LPBF and machining process based fabrication was investigated, and the influence of the process parameters on the formation of the surplus part and deformation of the machined surface was evaluated. In addition, a laser scan and machining strategy was formulated to improve the surface quality of the built part. The surplus buildup at the edge of the fabricated part occurred owing to the difference in the thermal properties between the solidified part and deposited metal powder. The laser-irradiated position at the first layer buildup and energy density were the principal factors affecting the formation of the surplus part, and the surplus buildup could be reduced using the laser scan strategy, in which the laser-irradiated position was shifted inward. The peripheral face of the built part formed periodical steps, owing to the deformation induced by the change in the thermal distribution inside the built part. These steps could be reduced using the machining strategy combining the rough machining process with a finishing allowance and stepwise finishing process.

A Study on Interferential Tool Position Correcting Algorithm in Rough Machining of 3d Impeller Variable-axis Plunge Milling

The plunge milling method has remarkably improved the rough machining efficiency of 3D impeller channel. However, in conventional cutter position planning for plunge milling, interference at the end of every cutter position due to sudden increase of radial depth is inevitable, which may seriously compromise the service life of machine tool and cutter, as well as the cutting efficiency at the interferential phase. This study optimized the cutter axis vector for the tool path of conventional rough machining of 3D impeller variable -axis plunge milling to make the angle between the normal vector for workpiece surface at the cutter contact point and the cutter-axis vector of adjacent tool position increase gradually from outlet to inlet at the smallest scale. Based on this, an iterative algorithm for tool center position and safety height for the cutter was provided, thus making the hub allowance of the optimized tool path for plunge milling as small as possible without affecting the subsequent machining on the premise of avoiding the interferential phenomenon. Finally, the correctness of the proposed method was verified by relevant numerical examples.

Material-scientific and technological aspects of ICE crankshaft disintegrations

The examples of crankshaft disintegration in modern internal combustion engines are considered. The cases of ICE crankshaft failure connected with the presence of manufacturing defects in them are analyzed: neck surface strengthening failure or its absence, metallurgic defects in material microstructure, necks and their lubrication grooves rough machining are analyzed. To determine the reasons of crankshaft disintegrations there was used a developed research complex for monitoring a structural state and analysis of motor car parts material disintegration during operation.

Integrated Kinematic Machining Error Compensation for Impeller Rough Tool Paths Programming in a Step-Nc Format Using Neural Network Approach Prediction

The most important components used in aerospace, ships, and automobiles are designed with free form surfaces. An impeller is one of the most important components that are difficult to machine because of its twisted blades. This research book is based on the premise that a STEP-NC program can document “generic” manufacturing information for an impeller. This way, a STEP-NC program can be made machine-independent and has an advantage over the conventional G-code-based NC program that is always generated for a specific CNC machine. Rough machining is recognized as the most crucial procedure influencing machining efficiency and is critical for the finishing process. The research work reported in this chapter focuses on introduces a fully STEP-compliant CNC by putting forward an interpolation algorithm for non uniform rational basic spline (NURBS) curve system for rough milling tool paths with an aim to solve the problems of kinematic errors solutions in five axis machine by neural network implementation.