Crater Geometry and Volume From Electro-Discharge Machined Surface Profiles by Data Dependent Systems

1980 ◽  
Vol 102 (4) ◽  
pp. 289-295 ◽  
Author(s):  
S. M. Pandit ◽  
K. P. Rajurkar
Keyword(s):  
Impulse Response Function ◽  
Surface Profile ◽  
Operating Conditions ◽  
Surface Generation ◽  
Radius Of Curvature ◽  
Regression Equations ◽  
Machining Time ◽  
Machined Surface ◽  
Depth Ratio ◽  
Single Discharge

This paper applies a recently developed methodology called Data Dependent Systems to model and analyse the process of Electro-Discharge Machined (EDM) surface generation. A first order stochastic differential equation is developed and physically interpreted from the EDM surface profile measurements under varying pulse duration and machining time. The impulse response function of this model is used to define a characteristic crater geometry. The depth and diameter to depth ratio of such a crater is determined and employed in deriving the radius of curvature and the volume. Experimental measurements are utilized to illustrate the development of regression equations and nomograms, useful in practice to obtain surfaces with desired geometry. It is shown that the depth diameter to depth ratio, and volume of the characteristic craters obtained from actual multiple discharge situation under operating conditions agree fairly well with the past single discharge physics investigations.

scholarly journals Effect of the lead angle and the radius of curvature on the cutting forces in a 5-axis milling of sculptured surfaces

Mechanik ◽  
2018 ◽  
Vol 91 (1) ◽  
pp. 18-22
Author(s):  
Michał Gdula ◽  
Jan Burek
Keyword(s):  
Turbine Blade ◽  
Convex Surface ◽  
Experimental Studies ◽  
Surface Profile ◽  
Radius Of Curvature ◽  
Sculptured Surface ◽  
Sculptured Surfaces ◽  
Inconel 718 Alloy ◽  
Machined Surface ◽  
Lead Angle

Experimental studies are presented, were conducted that aimed at determining the mathematical models of the influence of the lead angle and the radius of curvature of the profile of machined sculptured surface on the components of the cutting force. The object of the experimental studies was a convex and concave surface of a turbine blade of Inconel 718 alloy. The toroid cutter was used for the tests. Based on the results of the study it was found that the lead angle in the machining of the convex surface and concave turbine blade should be continuously varied with the change of radius of curvature in the direction of the machined surface profile.

Generation Mechanism and Quality of Milling Surface Profile for Variable Pitch Tools Considering Runout

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Jinbo Niu ◽  
Jinjie Jia ◽  
Yuwen Sun ◽  
Dongming Guo
Keyword(s):  
Process Parameters ◽  
Surface Profile ◽  
Generation Mechanism ◽  
Dynamic Responses ◽  
Surface Generation ◽  
Tool Geometry ◽  
Machined Surface ◽  
Variable Pitch ◽  
Surface Location Error ◽  
Machining System

Abstract Surface profile is one of the foremost aspects to evaluate milling performance. Its generation mechanism is affected by a variety of factors such as tool geometry, runout values, and process parameters and thus still deserves further investigation. This paper aims to propose a unified method to study the surface generation mechanism and to predict the machining quality for variable pitch tools considering runout. First, a Floquet theory based algorithm is extended to analyze the machining stability and output the dynamic responses of the machining system. The resultant trajectories of cutting edges are obtained by kinematic synthesis of system vibrations, tool rotations, and machining feed. Next, both the surface location error (SLE) and the surface roughness are simultaneously extracted from the edge trajectories. A series of cutting tests are performed to validate the prediction results. Some new characteristics of the machined surface profile in terms of form errors and teeth marks are discovered and theoretically explained. Finally, the joint influences of tool geometry, runout values, and process parameters on the surface generation mechanism and quality are analyzed in detail with the proposed method.

Experimental investigation of the influence of cutting parameters on surface quality and on the special characteristics of micro-milled surfaces of hardened steels

2021 ◽  
pp. 095440622110130
Author(s):  
Barnabás Zoltán Balázs ◽  
Márton Takács
Keyword(s):  
Surface Quality ◽  
Surface Profile ◽  
Cutting Parameters ◽  
Relevant Information ◽  
Milling Process ◽  
Micro Milling ◽  
Machined Surface ◽  
Analysis Of Dynamics ◽  
Five Axis ◽  
Coated Carbide

Micro-milling is one of the most essential technologies to produce micro components, but due to the size effect, it has many special characteristics and challenges. The process can be characterised by strong vibrations, relatively large run-out and tool deformation, which directly affects the quality of the machined surface. This paper deals with a detailed investigation of the influence of cutting parameters on surface roughness and on the special characteristics of micro-milled surfaces. Several systematic series of experiments were carried out and analysed in detail. A five-axis micromachining centre and a two fluted, coated carbide micro-milling tool with a diameter of 500 µm were used for the tests. The experiments were conducted on AISI H13 hot-work tool steel and Böhler M303 martensitic corrosion resistance steel with a hardness of 50 HRC in order to gain relevant information of machining characteristics of potential materials of micro-injection moulding tools. The effect of the cutting parameters on the surface quality and on the ratio of Rz/ Ra was investigated in a comprehensive cutting parameter range. ANOVA was used for the statistical evaluation. A novel method is presented, which allows a detailed analysis of the surface profile and repetitions, and identify the frequencies that create the characteristic profile of the surface. The procedure establishes a connection between the frequencies obtained during the analysis of dynamics (forces, vibrations) of the micro-milling process and the characterising repetitions and frequencies of the surface.

A Starved Mixed Elastohydrodynamic Lubrication Model for the Prediction of Lubrication Performance, Friction and Flash Temperature With Arbitrary Entrainment Angle

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Wei Pu ◽  
Dong Zhu ◽  
Jiaxu Wang
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Elastohydrodynamic Lubrication ◽  
Industrial Applications ◽  
Operating Conditions ◽  
Flash Temperature ◽  
Machined Surface ◽  
Lubrication Performance ◽  
Wide Range ◽  
Starved Lubrication

In this study, a modified mixed lubrication model is developed with consideration of machined surface roughness, arbitrary entraining velocity angle, starvation, and cavitation. Model validation is executed by means of comparison between the obtained numerical results and the available starved elastohydrodynamic lubrication (EHL) data found from some previous studies. A comprehensive analysis for the effect of inlet oil supply condition on starvation and cavitation, mixed EHL characteristics, friction and flash temperature in elliptical contacts is conducted in a wide range of operating conditions. In addition, the influence of roughness orientation on film thickness and friction is discussed under different starved lubrication conditions. Obtained results reveal that inlet starvation leads to an obvious reduction of average film thickness and an increase in interasperity cavitation area due to surface roughness, which results in significant increment of asperity contacts, friction, and flash temperature. Besides, the effect of entrainment angle on film thickness will be weakened if the two surfaces operate under starved lubrication condition. Furthermore, the results show that the transverse roughness may yield thicker EHL films and lower friction than the isotropic and longitudinal if starvation is taken into account. Therefore, the starved mixed EHL model can be considered as a useful engineering tool for industrial applications.

scholarly journals Dynamic Generation of Machined Surfaces, Part 2: Construction of Surface Topography

1991 ◽  
Vol 113 (2) ◽  
pp. 145-153 ◽  
Author(s):  
G. M. Zhang ◽  
S. G. Kapoor
Keyword(s):  
Surface Topography ◽  
Random Excitation ◽  
Surface Generation ◽  
Distribution Model ◽  
Excitation System ◽  
Machined Surface ◽  
Spiral Trajectory ◽  
Vibratory Motion ◽  
Texture Generation ◽  
Simulation Results

In Part 1 of these two-part papers, a normal distribution model has been formulated to describe the random excitation system present during machining. Part 2 presents a methodology to dynamically generate the surface topography under the random excitation environment through computer simulation. The proposed methodology uses the tool vibratory motion along with the tool geometrical motion to construct the topography of a machined surface. Both experimental and simulation results confirm that when a small feed is used, the influence of the spiral trajectory of tool geometrical motion on the surface generation decays dramatically and the random excitation system, on the opposite, is strengthened playing a significant role in surface texture generation.

scholarly journals 5-Axis Flank Milling Tool Path Smoothing Based on Kinematical Behaviour Analysis

2011 ◽  
Vol 223 ◽  
pp. 691-700 ◽  
Author(s):  
Xavier Beudaert ◽  
Pierre Yves Pechard ◽  
Christophe Tournier
Keyword(s):  
Tool Path ◽  
Maximum Velocity ◽  
Flank Milling ◽  
Machining Time ◽  
Machined Surface ◽  
Tool Paths ◽  
Area Of Interest ◽  
Milling Tool ◽  
Joint Coordinates ◽  
Kinematical Behaviour

In the context of 5-axis flank milling, the machining of non-developable ruled surfaces may lead to complex tool paths to minimize undercut and overcut. The curvature characteristics of these tool paths generate slowdowns affecting the machining time and the quality of the machined surface. The tool path has to be as smooth as possible while respecting the maximum allowed tolerance. In this paper, an iterative approach is proposed to smooth an initial tool path. An indicator of the maximum feedrate is computed using the kinematical constraints of the considered machine tool, especially the maximum velocity, acceleration and jerk. Then, joint coordinates of the tool path are locally smoothed in order to raise the effective feedrate in the area of interest. Machining simulation based on a N-buffer algorithm is used to control undercut and overcut. This method has been tested in flank milling of an impeller and can be applied in 3 to 5-axis machining.

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.

The Abrasion Mechanism of a Diamond Grinding Wheel with Resin Cured by Ultraviolet Light

2015 ◽  
Vol 809-810 ◽  
pp. 21-26 ◽  
Author(s):  
Qiu Yun Huang ◽  
Lei Guo ◽  
Ioan Marinescu
Keyword(s):  
Energy Cost ◽  
High Efficiency ◽  
Surface Profile ◽  
Diamond Wheel ◽  
Grinding Wheel ◽  
Experimental Setting ◽  
Machining Time ◽  
A Value ◽  
Small Grains ◽  
Abrasive Tools

Ultraviolet-cured resin bond, abrasive tools have been studied and have proven to have substantial advantages over conventional abrasive tools, not only in low energy cost and high efficiency when manufacturing the tool itself, but also in better performance when machining some materials [1,2]. However, very little research has been done to study the mechanism of UV cured abrasive tools. Nevertheless, many researchers have investigated the performances of such tools compared with some conventional tools. A mechanism of UV cured, resin bond, diamond wheel was proposed as the hybrid of grinding and lapping, which is called as grind/lap (G/L) process [3]. In the paper, the proposed mechanism was verified by comparing the experimental results of three processes. Three wheels were used to simulate grinding, lapping and grind/lapping operation separately under the same experimental setting. The results showed that the RA obtained by G/L wheel decreased to a value between those gained by grinding and lapping operations after 10 minutes and it became the lowest of the three as time increases. The RA and MRR of three processes indicated that at the beginning of operation, the abrasives in G/L wheel are fixed by the cured resin, and as machining time increases, the small grains get released from the wheel and act as loose abrasives. Therefore, the mechanism of the UV cured resin bond diamond wheel is verified as the dominant grinding at the beginning and lapping at the end, which was also illustrated by the surface profile of machined part.

Polymer-Bitumen Binders Compositions Selection by Using the Experimental Planning Method

2021 ◽  
Vol 887 ◽  
pp. 504-510
Author(s):  
V.D. Galdina ◽  
N.S. Galdin
Keyword(s):  
Operating Conditions ◽  
Planning Method ◽  
Regression Equations ◽  
Experimental Planning ◽  
Petroleum Bitumen ◽  
Styrene Butadiene Styrene ◽  
Technical Properties ◽  
And Performance ◽  
Styrene Butadiene ◽  
Butadiene Styrene

The paper presents the studies on the compositions selection and properties of polymer-bitumen binders obtained using the viscous petroleum bitumen, styrene-butadiene-styrene polymer and plasticizer according to the experimental planning method. Regression equations of the polymer-bitumen binders processing and performance properties, which make it possible to optimize the compositions and predict their properties taking into account the operating conditions, were obtained. Polymer-bitumen binders in comparison with the properties of viscous road bitumen have the increased indicators of heat resistance, crack toughness, ductility and elasticity. To obtain the adequate mathematical model, the experimental data were processed, compositions were optimized and dependence diagrams were constructed by using the Maple software package. The software for a personal computer including the algorithm and program for selecting the polymer-bitumen binders has been developed. When using the software it is possible to automate the calculation of the polymer-bitumen binders compositions with a given set of technical properties.

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