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.

Experimental Investigation and Optimization in Rotary Ultrasonic Drilling of C/C Composites

2016 ◽  
Vol 874 ◽  
pp. 313-319
Author(s):  
Song Mei Yuan ◽  
Qi Wu
Keyword(s):  
Feed Rate ◽  
Elevated Temperatures ◽  
Cutting Parameters ◽  
Spindle Speed ◽  
High Fracture Toughness ◽  
Drilling Force ◽  
High Fracture ◽  
Machining Quality ◽  
Ultrasonic Drilling ◽  
Rotary Ultrasonic Drilling

C/C composites are widely used in aviation and aerospace due to their low density, superior specific strength, special elastic modulus at elevated temperatures, small thermal expansion coefficient and high fracture toughness. However, there are numerous problems such as delamination, chipping, poor machining quality and tool wear in drilling of C/C composites due to inhomogeneous, anisotropic, wear resistance and varying thermal properties of the composites. In this paper, related experiments on rotary ultrasonic drilling of C/C composites using diamond core drill were conducted to compare the drilling force and machining quality of ultrasonic drilling with conventional drilling, analyze the rotary ultrasonic drilling mechanism and research the influence of spindle speed, feed rate and ultrasonic amplitude on the drilling force. Experimental results showed that rotary ultrasonic drilling can significantly improve the removal of the chips thus preventing the core drill blockage, effectively reduce the drilling force and improve processing quality. In addition, the drilling force decreased with increasing of spindle speed and ultrasonic amplitude, while it increased with increasing of feed rate. Finally, the cutting parameters were optimized by consideration of the drilling force and efficiency.

scholarly journals Simulation of incremental forming processes of a pyramidal ring made of two materials

2018 ◽  
Vol 19 (3) ◽  
pp. 313
Author(s):  
Masood Ghassabi ◽  
Milad Salimi ◽  
Mohammad Haghpanahi
Keyword(s):  
Feed Rate ◽  
Rotational Speed ◽  
Incremental Forming ◽  
Thickness Distribution ◽  
Single Point ◽  
Dimensional Accuracy ◽  
Cnc Machine ◽  
Forming Force ◽  
Forming Process ◽  
Dimensional Precision

Incremental forming is one of the most well-known forming processes for complex and asymmetric parts. This method uses a CNC machine, simple forming tool, and a die. This study focused on effects of some parameters such as the material, feed rate, pitch, rotational speed and movement strategy of tool on the dimensional precision, forming force, thickness distribution and fracture in the welding area. The results showed that single point incremental forming (SPIF) led to a better thickness distribution with lower tool force, whereas two-point incremental forming led to better dimensional accuracy. Rotational speed does not have any significant impact on the forming process while decreasing the feed rate partially reduced the forming force. According to the results, although dimensional precision in double point incremental forming is better than SPIF, when it comes to the thickness distribution, forming force, and economic issues, SPIF is in favor. The results also showed that by connecting two materials, different parameters for the two materials could be investigated simultaneously in one simulation process.

Experiments of Drilling Titanium Alloy with Varying Operation Parameters

2017 ◽  
Vol 748 ◽  
pp. 254-258
Author(s):  
Chang Yi Liu ◽  
Bai Shou Zhang ◽  
Suman Shrestha
Keyword(s):  
Titanium Alloy ◽  
Feed Rate ◽  
Thrust Force ◽  
Maximum Amount ◽  
Spindle Speed ◽  
Drilling Process ◽  
Process Variables ◽  
Experimental Cutting ◽  
Operation Parameters ◽  
Titanium Alloy Ti6al4v

Drilling experiments of titanium alloy Ti6Al4V were conducted. Taking the speed and feed as the process variables, a set of experimental cutting forces are obtained and compared. From the experimental results it is concluded that within the experimental extent the thrust force and torque of drilling process rises with the feed rate. The lower spindle speed resulted in the greater amount of thrust. Feed rates have greater influence on the thrust force than the spindle speed. The combination of greater feed rate and lower spindle speed results in the maximum amount of thrust. However, combination of greater feed rate and spindle speed resulted in maximum amount of torque.

Dimensional accuracy of FDM-printed polymer parts

2019 ◽  
Vol 26 (2) ◽  
pp. 288-298 ◽  
Author(s):  
Oğuzhan Emre Akbaş ◽  
Onur Hıra ◽  
Sahar Zhiani Hervan ◽  
Shahrad Samankan ◽  
Atakan Altınkaynak
Keyword(s):  
Experimental Data ◽  
Numerical Model ◽  
Feed Rate ◽  
Fused Deposition Modeling ◽  
Dimensional Accuracy ◽  
Acrylonitrile Butadiene Styrene ◽  
Strip Width ◽  
Content Type ◽  
Fused Deposition ◽  
Nozzle Temperature

Purpose This paper aims to analyze experimentally and numerically the effect of the nozzle temperature and feed rates on the dimensions of the fused deposition modeling (FDM) polymer parts. Design/methodology/approach In total, 30 strips per sample were printed with the same width as the nozzle diameter. The strips were printed with one vertical movement of the nozzle head. The width of the strips was measured with a caliper at five locations. A linear regression model was created based on the experimental data to understand the correlation between the strip width deviation and the parameters of interest. Numerical simulations were performed to predict the swell of the polymer exiting the nozzle using finite element method combined with level set method. The experimental results were then used to validate the models. Findings The average accuracy of polylactic acid (PLA) samples was better than that of acrylonitrile butadiene styrene (ABS) samples. The average strip width had a tendency to increase with increasing temperature for PLA samples, whereas ABS samples showed mixed behavior. The strip width decreased with increasing feed rate for most cases. The measurement positions had a major effect on strip width when compared to nozzle temperature and feed rate. The numerical model predictions were in good agreement with the experimental data. A few discrepancies were observed at high feed rates and nozzle temperatures. Originality/value This study will contribute to gaps in knowledge regarding the effect of processing conditions on dimensional accuracy of FDM-printed parts. The developed numerical model can be efficiently used to predict the dimensional accuracy of FDM-printed parts.

scholarly journals Analysis of PLA Geometric Properties Processed by FFF Additive Manufacturing: Effects of Process Parameters and Plate-Extruder Precision Motion

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1581 ◽  
Author(s):  
Eustaquio García Plaza ◽  
Pedro Núñez López ◽  
Miguel Caminero Torija ◽  
Jesús Chacón Muñoz
Keyword(s):  
Layer Thickness ◽  
Surface Texture ◽  
Feed Rate ◽  
Low Cost ◽  
Dimensional Accuracy ◽  
3D Printer ◽  
Geometric Properties ◽  
Geometric Precision ◽  
Functional Components ◽  
Flatness Error

The evolution of fused filament fabrication (FFF) technology, initially restricted to the manufacturing of prototypes, has led to its application in the manufacture of finished functional products with excellent mechanical properties. However, FFF technology entails drawbacks in aspects, such as dimensional and geometric precision, and surface finish. These aspects are crucial for the assembly and service life of functional parts, with geometric qualities lagging far behind the optimum levels obtained by conventional manufacturing processes. A further shortcoming is the proliferation of low cost FFF 3D printers with low quality mechanical components, and malfunctions that have a critical impact on the quality of finished products. FFF product quality is directly influenced by printer settings, material properties in terms of cured layers, and the functional mechanical efficiency of the 3D printer. This paper analyzes the effect of the build orientation (Bo), layer thickness (Lt), feed rate (Fr) parameters, and plate-extruder movements on the dimensional accuracy, flatness error, and surface texture of polylactic acid (PLA) using a low cost open-source FFF 3D printer. The mathematical modelling of geometric properties was performed using artificial neural networks (ANN). The results showed that thinner layer thickness generated lower dimensional deviations, and feed rate had a minor influence on dimensional accuracy. The flatness error and surface texture showed a quasi-linear behavior correlated to layer thickness and feed rate, with alterations produced by 3D printer malfunctions. The mathematical models provide a comprehensive analysis of the geometric behavior of PLA processing by FFF, in order to identify optimum print settings for the processing of functional components.

Characterization of Cutting-Induced Heat Generation in Ultra-Precision Milling of Aluminium Alloy 6061

2013 ◽  
Vol 552 ◽  
pp. 201-206
Author(s):  
Su Juan Wang ◽  
Suet To ◽  
Xin Du Chen
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Heat Generation ◽  
Feed Rate ◽  
Dimensional Accuracy ◽  
Precision Machining ◽  
Machined Surface ◽  
Single Crystal Diamond ◽  
Ultra Precision ◽  
Alloy 6061

The technology of ultra-precision machining with single crystal diamond tool produces advanced components with higher dimensional accuracy and better surface quality. The cutting-induced heat results in high temperature and stress at the chip-tool and tool-workpiece interfaces therefore affects the materials and the cutting tool as well as the surface quality. In the ultra-precision machining of al6061, the cutting-induced heat generates precipitates on the machined surface and those precipitates induce imperfections on the machined surface. This paper uses the time-temperature-precipitation characteristics of aluminum alloy 6061 (al6061) to investigate the effect of feed rate on the cutting-induced heat generation in ultra-precision multi-axis milling process. The effect of feed rate and feed direction on the generation of precipitates and surface roughness in ultra-precision raster milling (UPRM) is studied. Experimental results show that heat generation in horizontal cutting is less than that in vertical cutting and a larger feed rate generates more heat on the machined workpiece. A smaller feed rate produces a better surface finish and under a larger feed rate, scratch marks are produced by the generated precipitates and increase surface roughness.

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%.

Sign in / Sign up

Export Citation Format

Share Document