Development of a Small Rotary Multi-Jet Abrasive Fluid Jet Polishing Tool

2014 ◽  
Vol 625 ◽  
pp. 140-148 ◽  
Author(s):  
Assefa Asmare Tsegaw ◽  
Fang Jung Shiou
Keyword(s):  
Surface Roughness ◽  
Optical Glass ◽  
Fluid Pressure ◽  
Head Rotation ◽  
Angular Speed ◽  
Diamond Turning ◽  
Optimal Parameters ◽  
Optical Glasses ◽  
Control Factors ◽  
Polishing Tool

Most optical glasses are in recent years being manufactured by diamond turning processes which has certainly modernized the field of production of optics. Confines of diamond turning for both form and surface finish accuracy have not been reached, yet. In advent of contemporary technology, high precision finishing techniques are of great concern and the need of present industrialized-scenario. This paper presents the development of a small rotary multi-jet abrasive fluid jet polishing tool for use in polishing of optical glasses. The newly designed and manufactured tool has relative angular speed with respect to the spindle of machining centre and is capable of polishing at micro levels. The paper also investigates the optimal polishing parameters for selected, crown optical glass based on experiments conducted using Taguchi’s experimental method. According to the possible number of control factorsL18orthogonal array was used. ANOVA analysis was carried out to determine the main factors which would affect the surface roughness significantly. Consequently, a 2.5 μm size of Al2O3abrasive, 10wt% abrasive concentration, 40 rpm of polishing head rotation, 6 numbers of nozzles, 6 kg/cm2of fluid pressure, 45minuet of polishing time and 40% of step over have been found to be the optimal parameters. It was observed that about 97.22% improvements on surface roughness; Ra, from 0.360 μm to 0.010 μm has been achieved using the optimal parameters. In addition to this; rotation of polishing head, applied fluid pressure and polishing time were found to have significant effect on surface roughness improvement.

Development of a Self-Propelled Multi-Jet Polishing Tool for Ultra Precision Polishing

2014 ◽  
Vol 939 ◽  
pp. 481-490
Author(s):  
Assefa Asmare Tsegaw ◽  
Fang Jung Shiou
Keyword(s):  
Surface Roughness ◽  
Surface Finish ◽  
Turbine Blades ◽  
Angular Speed ◽  
Optimal Parameters ◽  
Optical Glasses ◽  
High Kinetic Energy ◽  
Ultra Precision ◽  
Head Pressure ◽  
Polishing Tool

As the needs of optical glasses are on the rise, the precision on shape, form, surface qualities and the scaling down of sizes are rising, too. The standards and surface finish of reference mirrors used in measuring appliances are crucial; hence, enhancement of the surface finish is indispensable in manufacturing industries. This paper proposes a self-propelled multi jet polishing technique for ultra precision polishing process in which bladelessTesla turbinewas used as a prime mover. The turbine is characterized by high swirling velocity at the outlet; therefore, high kinetic energy in the course of away from the turbine was used as polishing energy. Simulation of the flow of the field of turbine blades using computational fluid dynamics software (CFD) has also been presented. With a newly designed and manufactured polishing tool, this paper investigates the optimal polishing parameters for surface roughness improvement of crown optical glasses using Taguchis experimental approach; signal-to-nose (S/N) ratio and ANOVA analysis was also carried out to determine the effect of main factors on the surface roughness. Consequently, a 2.5μm size of Al2O3abrasive, 10wt% abrasive concentration, 80rpm of polishing head, 6 numbers of nozzles, 6 kg/cm2of pressure, and 45min. of polishing time have been found to be the optimal parameters. It was observed that about 94.44% improvements on surface roughness; Ra, from 0.360μm to 0.020μm has been achieved using the optimal parameters. In addition to this; angular speed of polishing head, pressure and polishing time were found to have significant effect on surface roughness improvement.

Investigation of Optimal Air-Driving Fluid Jet Polishing Parameters for the Surface Finish of N-BK7 Optical Glass

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Pham Huu Loc ◽  
Fang-Jung Shiou ◽  
Zong-Ru Yu ◽  
Wei-Yao Hsu
Keyword(s):  
Surface Roughness ◽  
Surface Finish ◽  
Orthogonal Array ◽  
Optical Glass ◽  
Impact Angle ◽  
Air Pressure ◽  
Standoff Distance ◽  
Optimal Parameters ◽  
Abrasive Material ◽  
Spherical Lens

The aim of this study is to investigate optimal air-driving fluid jet polishing (FJP) parameters by using Taguchi's method to improve surface roughness of N-BK7 optical glass on a machining center. An orthogonal array and the signal-to-noise (S/N) ratio are employed to determinate the optimal polishing parameters, and analysis of variance (ANOVA) is used to identify the main parameters that affect the surface roughness of the N-BK7 optical glass. An air-driving FJP tool is newly designed and fabricated to conduct experiments. To determinate the optimal air-driving FJP parameters, six polishing parameters, namely air pressure, impact angle, standoff distance, the abrasive material, abrasive concentration, and polishing time, are selected as the control factors of experiments. Based on the Taguchi's L18 orthogonal array experimental results and the S/N ratio, the optimal parameters for the N-BK7 optical glass are found. These optimal parameters are to be as follows: an air pressure of 0.490 MPa, an impact angle of 40 deg, a standoff distance of 12 mm, the abrasive material of Al2O3, an abrasive concentration of 10 wt. %, and a polishing time of 30 min. The surface roughness of specimen is improved from Ra = 0.350 μm–0.032 μm by using the optimal air-driving FJP parameters. In addition, the determined optimal polishing parameters for the plane surface are applied to the surface finish of an N-BK7 spherical lens, and the surface roughness of the spherical lens can be improved from Ra = 0.421 μm to 0.202 μm within an area of 283.6 μm × 200 μm.

scholarly journals Optimization of Honing Surface Roughness of Carburized Holes Based on GRA-RSM

Machines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 291
Author(s):  
Tao Tang ◽  
Chi Liu ◽  
Rong Wang
Keyword(s):  
Surface Roughness ◽  
Experimental System ◽  
Head Rotation ◽  
Optimal Parameters ◽  
Optimization Scheme ◽  
Internal Grinding ◽  
Surface Method ◽  
Low Efficiency ◽  
Set Up

The carburized holes processed by ordinary internal grinding are prone to burn, crack, and low efficiency. Honing has a superior machining efficiency and cooling effect compared to traditional internal grinding. In this paper, we innovatively apply honing to carburizing hole grinding and propose an effective optimization scheme to enhance the surface finish of carburized holes. We set up an experimental system to explore the influence law of honing head rotation speed, axial reciprocating speed, grain size, and single grinding depth on surface roughness. Based on the grey correlation and response surface method, we propose a method to optimize the honing parameters of carburized holes and establish a prediction model, which has an R2 value of 0.9887, indicating that the model fits well. We verify the validity of the model by the root mean square error of 0.012 between the measured and calculated values. Based on the model, the optimal parameters of roughness (Ra) is obtained and verified by experiments. Compared with the original honing parameters, the surface roughness quality is improved by 25.8%. It shows that the optimized honing process based on the GRA-RSM method improves the surface quality of carburized holes significantly.

Ultra Precision Surface Finishing Processes

2019 ◽  
Vol 13 (2) ◽  
pp. 174-184 ◽  
Author(s):  
Fang-Jung Shiou ◽  
Assefa Asmare Tsegaw ◽  
◽  
Keyword(s):  
Surface Roughness ◽  
Optical Glass ◽  
Load Cell ◽  
Cnc Machining ◽  
Machining Process ◽  
Surface Finishing ◽  
Cnc Machine ◽  
Ball Burnishing ◽  
Finishing Processes ◽  
Polishing Tool

Surfaces of different complex shapes are aspirated part of many scientific measuring devices, medical, astronomical, and other precision activity utilizations. Components at miniaturized level should meet required surface roughness for the intended applications. Surface finishing of freeform and miniaturized components are always difficult and need to look for a new way out. In this study, an attempt was made to improve surfaces roughness of selected, most frequently used, engineering materials using different innovative processes, which can be integrated with CNC machine centers. An advanced automated surface finishing tools such as ball burnishing embedded with load cell, vibration assisted polishing, and self-propelled abrasive multi-jet polishing tools are proposed. Ball burnishing is advantageous for pre-machining process of ball polishing. Using the polishing device embedded with load cell, the constant force polishing is achieved. To reduce the volumetric wear of a polishing ball, vibration assisted polishing device is also integrated. Moreover, self-propelled abrasive multi-jet polishing tool, which achieves 93.33% improvement of surface roughness for lapped optical glass of BK7 has been subjugated from Ra 0.300 μm to 0.020 μm. These tools can be miniaturized and applicable in small micro CNC machining centers.

Analysis of Surface Roughness and Waviness During Diamond Turning of Polycarbonate

2012 ◽  
Vol 2 (6) ◽  
pp. 268-270 ◽  
Author(s):  
Harinderpal Singh Harinderpal Singh ◽  
◽  
Rahul O vaishya ◽  
Karanvir Sing ◽  
Vinod Mishra ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Diamond Turning

Theoretical Surface Roughness Model in High Speed Face Milling

2014 ◽  
Vol 989-994 ◽  
pp. 3331-3334
Author(s):  
Tao Zhang ◽  
Guo He Li ◽  
L. Han
Keyword(s):  
Surface Roughness ◽  
Surface Integrity ◽  
High Speed ◽  
Cutting Parameters ◽  
Angular Speed ◽  
Face Milling ◽  
Advanced Manufacturing ◽  
Roughness Model ◽  
Machined Parts ◽  
Important Object

High speed milling is a newly developed advanced manufacturing technology. Surface integrity is an important object of machined parts. Surface roughness is mostly used to evaluate to the surface integrity. A theoretical surface roughness model for high face milling was established. The influence of cutting parameters on the surface roughness is analyzed. The surface roughness decreases when the cutter radius increases, total number of tooth and rotation angular speed, while it increases with the feeding velocity. The high speed face milling can get a smooth surface and it can replace the grinding with higher efficiency.

scholarly journals An Investigation of the High-Frequency Ultrasonic Vibration-Assisted Cutting of Steel Optical Moulds

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 460
Author(s):  
Canbin Zhang ◽  
Chifai Cheung ◽  
Benjamin Bulla ◽  
Chenyang Zhao
Keyword(s):  
Surface Roughness ◽  
Ultrasonic Vibration ◽  
High Frequency ◽  
Optical Glass ◽  
Contact Point ◽  
Cutting Speed ◽  
Optical Quality ◽  
Machining Parameters ◽  
Nose Radius ◽  
Cutting Geometry

Ultrasonic vibration-assisted cutting (UVAC) has been regarded as a promising technology to machine difficult-to-machine materials such as tungsten carbide, optical glass, and hardened steel in order to achieve superfinished surfaces. To increase vibration stability to achieve optical surface quality of a workpiece, a high-frequency ultrasonic vibration-assisted cutting system with a vibration frequency of about 104 kHz is used to machine spherical optical steel moulds. A series of experiments are conducted to investigate the effect of machining parameters on the surface roughness of the workpiece including nominal cutting speed, feed rate, tool nose radius, vibration amplitude, and cutting geometry. This research takes into account the effects of the constantly changing contact point on the tool edge with the workpiece induced by the cutting geometry when machining a spherical steel mould. The surface morphology and surface roughness at different regions on the machined mould, with slope degrees (SDs) of 0°, 5°, 10°, and 15°, were measured and analysed. The experimental results show that the arithmetic roughness Sa of the workpiece increases gradually with increasing slope degree. By using optimised cutting parameters, a constant surface roughness Sa of 3 nm to 4 nm at different slope degrees was achieved by the applied high-frequency UVAC technique. This study provides guidance for ultra-precision machining of steel moulds with great variation in slope degree in the pursuit of optical quality on the whole surface.

Surface roughness results using a hydrodynamic polishing tool (HyDra)

2004 ◽  
Author(s):  
Manuel Nunez ◽  
Javier Salinas ◽  
Esteban Luna ◽  
Luis Salas ◽  
Elfego Ruiz ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Polishing Tool

Surface and Sub-Surface Integrity of Ultra- Machined BK7 Using Fine and Coarse Grained Diamond Wheels

2007 ◽  
Vol 359-360 ◽  
pp. 234-238 ◽  
Author(s):  
Qing Liang Zhao ◽  
Bo Wang ◽  
Ekkard Brinksmeier ◽  
Otmann Riemer ◽  
Kai Rickens ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Integrity ◽  
High Surface ◽  
Coarse Grained ◽  
Nanometer Scale ◽  
Grinding Wheels ◽  
Fine Grained ◽  
Optical Glasses ◽  
Diamond Grinding ◽  
Surface Damages

This paper aims to evaluate the surface and sub-surface integrity of optical glasses which were correspondingly machined by coarse and fine-grained diamond grinding wheels on Tetraform ‘C’ and Nanotech 500FG. The experimental results show that coarse-grained diamond grinding wheels are capable of ductile grinding of optical glasses with high surface and sub-surface integrity. The surface roughness values are all in nanometer scale and the sub-surface damages are around several micros in depth, which is comparative to those machined by fine-grained diamond wheels.

Analysis of tool vibration and surface roughness during turning process of tempered steel samples using Taguchi method

2021 ◽  
pp. 095440892110019
Author(s):  
Menderes Kam ◽  
Mustafa Demirtaş
Keyword(s):  
Surface Roughness ◽  
Taguchi Method ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Machining Parameters ◽  
Turning Process ◽  
Machining Time ◽  
Tool Vibration ◽  
Control Factors ◽  
Tempered Steel

This study analyzed the tool vibration (Vib) and surface roughness (Ra) during turning of AISI 4340 (34CrNiMo6) tempered steel samples using Taguchi Method. In this context, Taguchi design L18 (21 × 32) was used to analyze the experimental results. The vibration amplitude values from cutting tools were recorded for different machining parameters, control factors; two different sample hardness (46 and 53 HRc), three different cutting speeds (180, 220, 260 m.min−1), and feed rates (0.08, 0.14, 0.20 mm.rev−1) were selected. The machining parameters giving optimum Vib and Ra values were determined. Regression analysis is applied to predict values of Vib and Ra. Analysis of variance was used to determine the effects of machining parameters on the Vib and Ra values. The most important machining parameters were found to be the feed rate, sample hardness, and cutting speed for Vib and Ra, respectively. The lowest Vib and Ra values were obtained in 46 HRc sample as 0.0022 gRMS and 0.255 µm, respectively. The surface quality can be improved by reducing the sources of vibration by using appropriate machining parameters. As a result, there is a significant relationship between Ra and Vib. The lower Ra values were found during turning process of tempered steel samples according to the literature studies. It is suggested that the process can be preferred as an alternative process to grinding process due to lower cost and machining time. In application of the turning of experiment samples by ceramic cutting tool, a substantial technological and economical benefit has been observed.

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