Budding Assembly Accuracy in the Presence of Workpiece Surface Roughness and Dimensional Error

2002 ◽  
Author(s):  
Grace H. Yu ◽  
Dariusz Ceglarek ◽  
Neville K. S. Lee
Keyword(s):  
Surface Roughness ◽  
Surface Generation ◽  
Simulation Methods ◽  
Surface Waviness ◽  
Dimensional Error ◽  
Workpiece Surface ◽  
Assembly Accuracy ◽  
Dimensional Errors

In this paper, simulation methods with improved surface generation techniques are used to study the accuracy of budding assembly processes. Our analysis shows that both the dimensional error and surface roughness together with surface waviness have significant effect on the budding assembly accuracy. In addition, we have found that even for the same parts with given dimensional errors, surface roughness and waviness, the budding assembly accuracy can still vary significantly depending on the different approaches of the alignment processes.

A Data Dependent Systems Approach to Dynamics of Surface Generation in Turning

1981 ◽  
Vol 103 (4) ◽  
pp. 437-445 ◽  
Author(s):  
S. M. Pandit ◽  
S. Revach
Keyword(s):  
Surface Roughness ◽  
Fourier Transform ◽  
Metal Cutting ◽  
Systems Approach ◽  
Cutting Conditions ◽  
Surface Generation ◽  
Chip Surface ◽  
Workpiece Surface ◽  
Independent Estimate ◽  
Micro Morphology

A new investigative approach to metal cutting dynamics is proposed based on wavelength decomposition of surface roughness by data dependent systems (DDS). This approach distinguishes from the commonly used Fourier transform analysis. It is shown to be capable of throwing light on both macroscopic and microscopic aspects of cutting mechanics. Workpiece surfaces from turning experiments, changing only speed and only feed, are used to illustrate that the macro-effects of cutting conditions and vibrations can be related to RMS components due to large wavelengths of a few tenths of mm magnitude. In particular, the so-called Spanzipfel effect is accounted for and its RMS is derived. It is also shown that wavelengths of a few micrometer magnitude, estimated from the workpiece surface roughness, seem to provide an independent estimate of chip surface lamellar widths in micro-morphology, well in agreement with earlier investigations.

Acoustic receptivity and evolution of two-dimensional and oblique disturbances in a Blasius boundary layer

2001 ◽  
Vol 432 ◽  
pp. 69-90 ◽  
Author(s):  
RUDOLPH A. KING ◽  
KENNETH S. BREUER
Keyword(s):  
Boundary Layer ◽  
Surface Roughness ◽  
Acoustic Wave ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Surface Waviness ◽  
S Wave ◽  
Boundary Layer Instability ◽  
Blasius Boundary Layer ◽  
Tollmien Schlichting

An experimental investigation was conducted to examine acoustic receptivity and subsequent boundary-layer instability evolution for a Blasius boundary layer formed on a flat plate in the presence of two-dimensional and oblique (three-dimensional) surface waviness. The effect of the non-localized surface roughness geometry and acoustic wave amplitude on the receptivity process was explored. The surface roughness had a well-defined wavenumber spectrum with fundamental wavenumber kw. A planar downstream-travelling acoustic wave was created to temporally excite the flow near the resonance frequency of an unstable eigenmode corresponding to kts = kw. The range of acoustic forcing levels, ε, and roughness heights, Δh, examined resulted in a linear dependence of receptivity coefficients; however, the larger values of the forcing combination εΔh resulted in subsequent nonlinear development of the Tollmien–Schlichting (T–S) wave. This study provides the first experimental evidence of a marked increase in the receptivity coefficient with increasing obliqueness of the surface waviness in excellent agreement with theory. Detuning of the two-dimensional and oblique disturbances was investigated by varying the streamwise wall-roughness wavenumber αw and measuring the T–S response. For the configuration where laminar-to-turbulent breakdown occurred, the breakdown process was found to be dominated by energy at the fundamental and harmonic frequencies, indicative of K-type breakdown.

Abrasive Waterjet Cutting of Aluminum Alloys: Workpiece Surface Roughness

2013 ◽  
Vol 404 ◽  
pp. 3-9 ◽  
Author(s):  
Nihat Tosun ◽  
Ihsan Dagtekin ◽  
Latif Ozler ◽  
Ahmet Deniz
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Aluminum Alloys ◽  
Abrasive Waterjet ◽  
Traditional Methods ◽  
Workpiece Surface ◽  
Abrasive Waterjet Machining ◽  
Waterjet Machining ◽  
Area Of Application ◽  
Better Than

Abrasive waterjet machining is one of the non-traditional methods of the recent years which found itself a wide area of application in the industry for machining of different materials. In this paper, the surface roughness of 6061-T6 and 7075-T6 aluminum alloys are being cut with abrasive waterjet is examined experimentally. The experiments were conducted with different waterjet pressures and traverse speeds. It has been found that the surface roughness obtained by cutting material with high mechanical properties is better than that of obtained by cutting material with inferior mechanical properties.

Effect of Mechanical Alignment System on Assembly Accuracy

2000 ◽  
Author(s):  
Neville K. S. Lee ◽  
Grace H. Yu ◽  
Y. Zou ◽  
J. Y. Chen ◽  
Ajay Joneja
Keyword(s):  
Alignment Accuracy ◽  
Mechanical Alignment ◽  
Mechanical Assembly ◽  
Surface Waviness ◽  
Form Errors ◽  
Multi Stage ◽  
Assembly Accuracy ◽  
Alignment System ◽  
Simulation Based ◽  
Selection Of

Abstract Mechanical means of positioning are frequently used in mechanical assembly processes. However, very little attention has been paid to the selection of mechanical alignment systems (MAS) for assembly processes. Our analysis shows that if the MAS are not properly selected, the form errors as well surface waviness and roughness of the workpieces to be assembled can badly limit the level of accuracy achievable. A simulation-based methodology is described to study the alignment accuracy for multi-stage processes. Such cases are common, where fabrication operations are done on parts before they are assembled. The study shows that if the workpieces are aligned in the same orientation, using similar or identical MAS for the fabrication processes and assembly processes, then the effect of the form errors as well as surface waviness and roughness of the workpieces can be greatly suppressed.

Generation mechanism modeling of surface topography in tangential ultrasonic vibration-assisted grinding with green silicon carbide abrasive wheel

2021 ◽  
pp. 095440542110406
Author(s):  
Yutong Qiu ◽  
Jingfei Yin ◽  
Yang Cao ◽  
Wenfeng Ding
Keyword(s):  
Surface Roughness ◽  
Surface Topography ◽  
Ultrasonic Vibration ◽  
Generation Mechanism ◽  
Surface Generation ◽  
Depth Of Cut ◽  
Abrasive Wheel ◽  
Grinding Parameters ◽  
Conventional Grinding ◽  
Ultrasonic Vibration Assisted Grinding

Tangential ultrasonic vibration-assisted grinding (TUAG) has a wide prospect in machining difficult-to-machine materials. However, the surface generation mechanism in TUAG is not fully recovered. This study proposes an analytical model of the surface topography produced by TUAG. Based on the model, the surface topography and roughness are predicted and experimentally verified. In addition, the influence of the grinding parameters on the surface topography is analyzed. The predicted surface topography well coincides with experimental measurements, and the prediction error in surface roughness Ra by the proposed model is less than 5%. Compared with conventional grinding, TUAG produces a surface with more uniform scratches and surface roughness Ra was reduced by up to 27% with the proper parameters. However, the improvement of surface roughness in TUAG is weakened when grinding speed or depth of cut increases. Moreover, the influence of the ultrasonic vibration amplitude on the surface roughness is not monotonous. With the grinding parameters selected in this study, TUAG with an ultrasonic amplitude of 7.5 μm produces the minimum surface roughness.

On the Flexible Abrasive Tool for Nanofinishing of Complex Surfaces

2019 ◽  
Vol 18 (01) ◽  
pp. 157-166 ◽  
Author(s):  
Mithun Sarkar ◽  
V. K. Jain ◽  
Ajay Sidpara
Keyword(s):  
Surface Roughness ◽  
Corrosion Inhibitor ◽  
Abrasive Tool ◽  
End Mill ◽  
Complex Surfaces ◽  
Ball End Mill ◽  
Workpiece Surface ◽  
Abrasive Particles ◽  
Processing Step ◽  
Finishing Tool

Nanofinishing of complex surfaces is an important but costly processing step for many products for performing their functions satisfactorily. This paper deals with the development of a flexible abrasive tool for nanofinishing of complex surfaces. A flexible finishing tool similar to the ball end mill is developed by curing Polydimethylsiloxane (PDMS). A bowl-shaped copper workpiece is finished to nanometer surface roughness value. Different sizes of abrasive particles are used to reduce surface roughness value of the workpiece. A corrosion inhibitor is mixed with the abrasive slurry to protect the finished copper workpiece surface. A final surface roughness value of 50[Formula: see text]nm has been achieved with a variation up to 70[Formula: see text]nm on different locations of the bowl-shaped workpiece.

Research on Surface Roughness Prediction Model for High-Speed Milling Inclined Plane of Hardened Steel

2010 ◽  
Vol 97-101 ◽  
pp. 2044-2048 ◽  
Author(s):  
Yuan Ling Chen ◽  
Bao Lei Zhang ◽  
Wei Ren Long ◽  
Hua Xu
Keyword(s):  
Surface Roughness ◽  
Prediction Model ◽  
High Speed ◽  
Hardened Steel ◽  
Prediction Errors ◽  
Inclined Plane ◽  
Workpiece Surface ◽  
Factors Influencing ◽  
Generalized Regression Neural Networks ◽  
Roughness Prediction

As the factors influencing the workpiece surface roughness is complexity and uncertainty, according to orthogonal experimental results, the paper established Empirical regression prediction model and generalized regression neural networks (GRNN) for prediction of surface roughness when machining inclined plane of hardened steel in high speed , moreover, compared their prediction errors. The results show that GRNN model has better prediction accuracy than empirical regression prediction model and can be better used to control the surface roughness dynamically.

Hydrodynamic Lubrication and Wear in Wavy Contacting Face Seals

1978 ◽  
Vol 100 (1) ◽  
pp. 81-90 ◽  
Author(s):  
A. O. Lebeck ◽  
J. L. Teale ◽  
R. E. Pierce
Keyword(s):  
Surface Roughness ◽  
Hydrodynamic Lubrication ◽  
Surface Profile ◽  
Operating Conditions ◽  
Face Seal ◽  
Hydrodynamic Load ◽  
Surface Waviness ◽  
Wear Rates ◽  
Elastic Deflection ◽  
Face Seals

A model of face seal lubrication is proposed and developed. Hydrodynamic lubrication for rough surfaces, surface waviness, asperity load support, elastic deflection, and wear are considered in the model. Predictions of the ratio of hydrodynamic load support to asperity load support are made for a face seal sealing a low viscosity liquid where some contact does occur and surface roughness is important. The hydrodynamic lubrication is caused by circumferential surface waviness on the seal faces. Waviness is caused by initial out of flatness or any of the various distortions that occur on seal ring faces in operation. The equilibrium solution to the problem yields one dimensional hydrodynamic and asperity pressure distributions, mean film thickness, elastic deflection, and friction for a given load on the seal faces. The solution is found numerically. It is shown that the fraction of hydrodynamic load support depends on many parameters including the waviness amplitude, number of waves around the seal, face width, ring stiffness, and most importantly, surface roughness. For the particular seal examined the fraction of load support would be small for the amount of waviness expected in this seal. However, if the surface roughness were lower, almost complete lift-off is possible. The results of the analysis show why the initial friction and wear rates in mechanical face seals may vary widely; the fraction of hydrodynamic load support depends on the roughness and waviness which are not necessarily controlled. Finally, it is shown how such initial waviness effects disappear as the surface profile is altered by wear. This may take a long or short time, depending on the initial amount of hydrodynamic load support, but unless complete liftoff is achieved under all operating conditions, the effects of initial waviness will vanish in time for steady state conditions. Practical implications are drawn for selecting some seal parameters to enhance initial hydrodynamic load support without causing significant leakage.

Sign in / Sign up

Export Citation Format

Share Document