Developmental and Experimental Study of Rotary Ultrasonic drilling process

The proper selection of machining conditions and machining parameter is an important aspect, before going to machine a brittle material by rotary ultrasonic drilling process Because these conditions will determine such important characteristics as; Material removal rate (MRR) and Surface roughness (SR). The purpose of this work is to determine the optimal values of machining parameters of rotary ultrasonic drilling process. The work has been based on the effect of three design factors: Tool feed rate, vibration frequency and grain size of abrasive particle on such characteristic like material removal rate (MRR). This work has been done by means of the technique of design of experiment (DOE), which provides us to perform the above-mentioned analysis with small number of experiments. In this work, a L9 orthogonal array is used to design the experiment. The adequate selection of machining parameters is very important in manufacturing system, because these parameters determine the surface quality and dimensional accuracy of the manufactured part. The optimal setting of the parameters are determined through experiments planned, conducted and analyzed using the Taguchi method. Keywords: RUSM, Material removal rate, Drilling, Taguchi method

Drilling of Additive Manufactured Poly Lactic Acid Modified byDrilling of Additive Manufactured Poly Lactic Acid Modified by Ultrasonic Vibration Ultrasonic Vibration

Complex geometries can be produced by using additively manufacturing method (AM). As usual, the AM parts have rough surfaces in which post processing operations are needed. One of the useful operations is ultrasonic drilling process. In this process, an additional movement is added to the cutting tool to improve the machinability factors. In this study, poly lactic acid(+) was selected as workpiece where the quality of the holes generated by ultrasonic drilling, were investigated. The examination parameters were delamination, circularity, and cylindricality. As a result, it was shown that UD process could properly improve the examination parameters. It was explained that harmonic movement of drill bit in UD improved the stability of the process by a decrease in cutting forces and chip adhesion. Moreover, a significant reduction was observed in delamination factor by using ultrasonic vibrations.

Investigation into rotary mode ultrasonic drilling of bioceramic: an experimental study with PSO-TLBO based evolutionary optimization

Purpose The purpose of this paper is to investigate experimentally the effect of several input process factors, namely, feed rate, spindle speed, ultrasonic power and coolant pressure, on hole quality measures (penetration rate [PR] and chipping diameter [CD]) in rotary mode ultrasonic drilling of macor bioceramic material. Design/methodology/approach The main experiments were planned using the response surface methodology (RSM). Scanning electron microscopy was also used to examine and study the microstructure of machined samples. This study revealed the existence of dominant brittle fracture and little plastic flow that resulted in a material loss from the base work surface. Experiment findings have shown the dependability and adequacy of the proposed mathematical model. Findings The percentage of brittle mode deformation rises as the penetration depth of abrasives increases (at increasing levels of feed rate). This was due to the fact that at greater depths of indentation, material loss begins in the form of bigger chunks and develops inter-granular fractures. These stated causes have provided an additional advantage to increasing the CD over the machined rod of bioceramic. The desirability method was also used to optimize multi-response measured responses (PR and CD). The mathematical model created using the RSM method will be very useful in industrial revelation. Furthermore, the investigated answers’ particle swarm optimization (PSO) and teacher-learner-based optimization (TLBO) make the parametric analysis more relevant and productive for real-life industrial practices. Originality/value Macor bioceramic has been widely recognized as one of the most highly demanded innovative dental ceramics, receiving expanded industry approval because of its outstanding and superior characteristics. However, effective and efficient processing remains a problem. Among the available contemporary machining methods introduced for processing typical and advanced materials, rotary mode ultrasonic machining has been identified as one of the best suitable candidates for precise processing of macor bioceramics, as this process produces thermal damage-free profiles, as well as high accuracy and an increased material removal rate. The optimized combined setting obtained using PSO is feed rate = 0.16 mm/s, spindle speed = 4,500 rpm, ultrasonic power = 60% and coolant pressure = 280 kPa with the value of fitness function is 0.0508. The optimized combined setting obtained using TLBO is feed rate = 0.06 mm/s, spindle speed = 2,500 rpm, ultrasonic power = 60% and coolant pressure = 280 kPa with the value of fitness function is 0.1703.

Evaluating the Hole Quality Produced by Vibratory Drilling: Additive Manufactured PLA+

Improving the surface quality of additive manufactured parts like poly lactic acid (+) is an important study that is currently being carried out by researchers. To reach the high quality, different conventional and non-conventional methods are applied. In this study, the capability of ultrasonic vibration in drilling of an additive manufactured poly lactic acid (+)was examined. The process was implemented in two methods: conventional and vibratory drilling. Then, thrust force and chip type were analyzed and the effect of them on surface roughness, delamination, circularity, and cylindricality have been investigated. As a result, it was indicated that lower thrust force and broken chips, which were generated in ultrasonic drilling, caused the surface quality parameters to be improved compared to the conventional method.