Investigation of vibration effects and tool shape on edge chipping phenomenon occurring during rotary ultrasonic drilling

2019 ◽  
Vol 439 ◽  
pp. 251-259 ◽  
Author(s):  
Milan Nad' ◽  
Lenka Kolíková ◽  
Ladislav Rolník ◽  
Rastislav Ďuriš
Keyword(s):  
Edge Chipping ◽  
Ultrasonic Drilling ◽  
Tool Shape ◽  
Rotary Ultrasonic Drilling

scholarly journals Application of Numerical Simulation for the Analysis of the Processes of Rotary Ultrasonic Drilling

2016 ◽  
Vol 24 (39) ◽  
pp. 151-158
Author(s):  
Milan Naď ◽  
Lenka Čičmancová ◽  
Štefan Hajdu
Keyword(s):  
Numerical Simulation ◽  
Resonance State ◽  
Hole Drilling ◽  
Ultrasonic Machining ◽  
Rotary Ultrasonic Machining ◽  
Final Phase ◽  
Machining Performance ◽  
Edge Chipping ◽  
Ultrasonic Drilling ◽  
Rotary Ultrasonic Drilling

Abstract Rotary ultrasonic machining (RUM) is a hybrid process that combines diamond grinding with ultrasonic machining. It is most suitable to machine hard brittle materials such as ceramics and composites. Due to its excellent machining performance, RUM is very often applied for drilling of hard machinable materials. In the final phase of drilling, the edge deterioration of the drilled hole can occur, which results in a phenomenon called edge chipping. During hole drilling, a change in the thickness of the bottom of the drilled hole occurs. Consequently, the bottom of the hole as a plate structure is exposed to the transfer through the resonance state. This resonance state can be considered as one of the important aspects leading to edge chipping. Effects of changes in the bottom thickness and as well as the fillet radius between the wall and bottom of the borehole on the stress-strain states during RUM are analyzed.

scholarly journals Precise Drilling of Holes in Alumina Ceramic (Al2O3) by Rotary Ultrasonic Drilling and its Parameter Optimization using MOGA-II

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1059 ◽  
Author(s):  
Hisham Alkhalefah
Keyword(s):  
Feed Rate ◽  
Dimensional Accuracy ◽  
Alumina Ceramic ◽  
Process Variables ◽  
Multi Objective Genetic Algorithm ◽  
Ultrasonic Drilling ◽  
Drilling Quality ◽  
Processing Techniques ◽  
Validation Tests ◽  
Rotary Ultrasonic Drilling

Alumina is an advanced ceramic with applications in dental and medical sciences. Since ceramics are hard and brittle, their conventional machining is expensive, arduous, and time-consuming. As rotary ultrasonic machining is among the most adequate and proficient processing techniques for brittle materials like ceramics. Therefore, in this study, rotary ultrasonic drilling (RUD) has been utilized to drill holes on alumina ceramic (Al2O3). This study investigates the effect of key RUD process variables, namely vibration frequency, vibration amplitude, spindle speed, and feed rate on the dimensional accuracy of the drilled holes. A four-variable three-level central composite design (thirty experiments on three sample plates) is utilized to examine the comparative significance of different RUD process variables. The multi-objective genetic algorithm is employed to determine the optimal parametric conditions. The findings revealed that material removal rates depend on feed rate, while the cylindricity of the holes is mostly controlled by the speed and feed rate of the spindles. The optimal parametric combination attained for drilling quality holes is speed = 4000 rpm, feed rate = 1.5 (mm/min), amplitude = 20 (µm), and frequency = 23 (kHz). The validation tests were also conducted to confirm the quality of drilled holes at the optimized process parameters.

Design of a Novel Air Bearing Workbench for Rotary Ultrasonic Drilling of Advanced Ceramics

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Liping Liu ◽  
Bin Lin ◽  
Fengzhou Fang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Bearing Capacity ◽  
Cutting Force ◽  
Air Bearing ◽  
The Novel ◽  
Advanced Ceramics ◽  
Air Damping ◽  
Ultrasonic Drilling ◽  
Rotary Ultrasonic Drilling

A novel air bearing workbench used in rotary ultrasonic drilling of advanced ceramics was designed to constantly and sensitively control the cutting force. Compared with traditional feed systems, the novel air bearing workbench features an aerostatic guide and a pneumatic actuator, so that it only overcomes the air damping when the cutting force is balanced. Thus, it can sensitively and constantly control the cutting force for rotary ultrasonic drilling of advanced ceramics. The aerostatic guide, which determines the eccentric bearing capacity and stiffness of the workbench, is the most important part. The forces applied on the aerostatic guide faces were analyzed to calculate the bearing capacity and stiffness of the workbench using varying gas film thicknesses with finite element method (FEM). Based on the result of the analysis, the best gas film thickness of the aerostatic guide was designed to be 30 μm. The real eccentric bearing capacity and stiffness of the workbench were measured. The error between experimental results and the FEM results was within 12%.

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