Analysis of the Acceleration Transfer in the Unguided Vibratory Finishing Process

2019 ◽  
Author(s):  
Maximilian Lachenmaier ◽  
Marius Ohlert ◽  
Daniel Trauth ◽  
Thomas Bergs
Keyword(s):  
Removal Rate ◽  
Contact Forces ◽  
Vibratory Finishing ◽  
Contact Conditions ◽  
Measurement Systems ◽  
Finishing Process ◽  
Transfer Behavior ◽  
Input Variables ◽  
Finishing Processes ◽  
First Time

Abstract The work bowl acceleration of a vibratory finishing machine is mainly determined by the process input variables, e. g. the mass distribution between the upper and the lower imbalance weights, the offset angle between these imbalance weights and the rotational speed of the imbalance motor. The acceleration of the work bowl has a strong effect on the acceleration of the abrasive media and workpiece within the work bowl and thus on their movement. This movement indirectly determines the contact conditions, contact forces and relative velocities, between the abrasive media and the workpiece. The contact conditions have a strong effect on the material removal rate and the surface roughness of the machined workpieces in a vibratory finishing process. Due to the fact that the contact conditions can hardly be measured during the vibratory finishing process a comprehensive understanding of the transfer behavior of the work bowl acceleration on the acceleration of the abrasive media and the workpiece and thus on the prevailing contact conditions is necessary. Therefore, this publication presents an innovative approach to identify these cause-effect relationships, in order to determine the machining intensity based on the work bowl acceleration as a function of the process input variables. Hence, new measurement systems are presented which enable the determination of the acceleration of the abrasive media and the workpiece as a function of the acceleration of the work bowl of a vibratory finishing machine for the first time. Based on these investigations it is possible to identify significant areas for the work bowl acceleration, as well as for the acceleration of the abrasive media and the workpiece and thus for the contact conditions, contact forces and relative velocities, which can be used for a targeted control of the machining intensity of vibratory finishing processes.

Contact Forces in Unguided Vibratory Finishing

2015 ◽  
Author(s):  
Richard Brocker ◽  
Frederik Vits ◽  
Patrick Mattfeld ◽  
Fritz Klocke
Keyword(s):  
Measurement System ◽  
Removal Rate ◽  
Electrical Power ◽  
Force Sensor ◽  
Contact Forces ◽  
Work Piece ◽  
Data Logging ◽  
Vibratory Finishing ◽  
Revolution Speed ◽  
Finishing Processes

In vibratory finishing the material removal rate is influenced by the contact forces between work piece and media. In this paper a measurement system is presented which is capable of measuring the contact forces between work piece and media in unguided vibratory finishing. The unique feature of the measurement system is its completely wireless construction. The measurement results are not influenced by wires of the force sensor system including the electrical power supply and the data logging. By means of this measurement system, contact forces can be measured in unguided vibratory finishing processes for the first time. Furthermore, the influence of media size and adjustment of the unbalance motor like revolution speed, phase angle and mass distribution between the upper and the lower eccentric weight was investigated.

Kontaktkräfte beim ungeführten Vibrationsgleitschleifen*/Contact forces in unguided vibratory finishing

2015 ◽  
Vol 105 (06) ◽  
pp. 377-383
Author(s):  
F. Klocke ◽  
R. Brocker ◽  
F. Vits ◽  
P. Mattfeld
Keyword(s):  
Measurement System ◽  
Electrical Power ◽  
Force Sensor ◽  
Contact Forces ◽  
Work Piece ◽  
Data Logging ◽  
Vibratory Finishing ◽  
Revolution Speed ◽  
Measurement Results ◽  
Finishing Processes

Beim Vibrationsgleitschleifen wird der Werkstoffabtrag maßgeblich durch die vorherrschenden Kontaktkräfte zwischen dem Werkstück und den Schleifkörpern bestimmt. Dieser Fachartikel stellt ein Messsystem vor, mit dem die messtechnische Erfassung der Kontaktkräfte beim ungeführten Vibrationsgleitschleifen möglich ist. Ein Alleinstellungsmerkmal ist dabei die vollständig kabellose Ausführung des Messsystems. Somit wurden die Messergebnisse nicht durch Kabel beeinflusst, die üblicherweise für die Energieversorgung und Datenübertragung notwendig sind. Mithilfe dieses Messsystems wurde der Einfluss folgender Prozesseingangsgrößen systematisch untersucht: Schleifkörpergröße, Unwuchtmotordrehzahl, Versatzwinkel der Unwuchtgewichte sowie die Masse des unteren und oberen Unwuchtgewichts auf die Kontaktkräfte.   In vibratory finishing the material removal is influenced by the contact forces between work piece and media. In this paper a measurement system is presented which is able to measure contact forces between work piece and media in unguided vibratory finishing. The unique feature of the measurement system is its completely wireless construction so that the measurement results are not influenced by wires of the force sensor system including the electrical power supply and the data logging. By means of this measurement system, contact forces can be measured in unguided vibratory finishing processes for the first time. Furthermore, the influence of media size and adjustment of the unbalance motor like revolution speed, phase angle and mass distribution between the upper and the lower eccentric weight on the contact forces was investigated.

Experimental Investigation of Vibratory Finishing Process

2014 ◽  
Author(s):  
Xiaozhong Song ◽  
Rahul Chaudhari ◽  
Fukuo Hashimoto
Keyword(s):  
Surface Roughness ◽  
Experimental Investigation ◽  
Metal Removal ◽  
Contact Forces ◽  
Chemical Solution ◽  
Impact Frequency ◽  
Vibratory Finishing ◽  
Factors Affecting ◽  
Finishing Process ◽  
Chemical Solutions

The vibratory finishing process is widely used for finishing metal components. An experimental investigation is reported on the factors affecting the metal removal and resultant surface roughness during vibratory finishing including the influence of chemical solutions. The effect of process parameters such as media size and impact frequency is studied by measuring the contact forces. A method to investigate the effect of chemical solution and to optimize the processing time to achieve desired resultant surface roughness is presented.

Minimum surface roughness using rule-based modeling of the vibratory finishing process in a high-frequency bowl system

2020 ◽  
Vol 234 (11) ◽  
pp. 1415-1421
Author(s):  
Ben Jin Wong ◽  
Ketav Majumdar ◽  
Kunal Ahluwalia ◽  
Swee-Hock Yeo
Keyword(s):  
First Principles ◽  
High Frequency ◽  
Force Sensor ◽  
Vibratory Finishing ◽  
Microscopy Imaging ◽  
Newtonian Physics ◽  
Mass Finishing ◽  
Finishing Process ◽  
Finishing Processes ◽  
Made In

Previous work on vibratory finishing has led to a better understanding and establishment of the mass finishing processes. Despite the sustained efforts made to date, vibratory finishing remains a field where the findings made have been based largely on empirical evidence. Through force sensor analyses and scanning electron microscopy imaging, in this work a successful attempt has been made in uncovering the underlying science—through first principles of Newtonian physics—behind vibratory finishing, providing explanations for the observations made. Trials were carried out in a high-frequency vibratory bowl, the first of its kind in the vibratory finishing industry. Through these trials, mathematical formulations have been derived, essentially providing a reliable way for the industry to estimate the process cycle time.

Nonlinear Vibration Analysis of Turbine Bladed Disks with Mid-Span Dampers

2021 ◽  
Author(s):  
Erhan Ferhatoglu ◽  
Stefano Zucca ◽  
Daniele Botto ◽  
Jury Auciello ◽  
Lorenzo Arcangeli
Keyword(s):  
Normal Load ◽  
Solution Procedure ◽  
Forced Response ◽  
Contact Forces ◽  
Steam Turbines ◽  
Bladed Disks ◽  
Contact Conditions ◽  
Nonlinear Dynamic Response ◽  
Friction Dampers ◽  
First Time

Abstract Friction dampers are one of the most common secondary structures utilized to alleviate excessive vibration amplitudes in turbo-machinery applications. In this paper, the dynamic behavior of the turbine bladed disks coupled with one of the special damper designs, the so-called Mid-Span Dampers (MSDs) that is commonly used in steam turbines of Baker Hughes Company, is thoroughly studied. Friction between the blade and the damper is modeled through a large number of contact nodes by using 2D contact elements with a variable normal load. In the solution procedure, the coupled static/dynamic Harmonic Balance approach is utilized for the first time in the assessment of the dissipation capability of MSDs, computationally shown by predicting the forced response levels of the system at different resonances. Moreover, it is demonstrated that the nonlinear dynamic response is non-unique and it may vary considerably even if all the user-controlled inputs are kept identical. This phenomenon is a novel observation for MSDs and it is explained by an uncertainty present in the contact forces. Contact conditions corresponding to multiple responses are also investigated to unveil the different kinematics of the damper under the same nominal conditions.

A Framework for the Analysis of Mass Finishing Processes

2012 ◽  
Vol 565 ◽  
pp. 284-289 ◽  
Author(s):  
Stephen Wan
Keyword(s):  
Computational Fluid Dynamic ◽  
Granular Flow ◽  
Fluid Dynamic ◽  
Vibratory Finishing ◽  
Short Introduction ◽  
Mass Finishing ◽  
Finishing Process ◽  
Practical Analysis ◽  
Finishing Processes

The aim of this paper is to introduce, in broad strokes, a framework – constructed from a fusion of granular flow (GFD) dynamics, tribology and computational fluid dynamic (CFD) techniques – for the practical analysis of mass finishing processes. The presentation opens with a short introduction to typical mass finishing processes, followed by a brief discussion on their respective correspondences to GFD regimes, and ends which some illustrative results arising from the application of this framework to vibratory finishing, which is perhaps the most industrially pervasive mass finishing process.

Simulation of 1D Abrasive Vibratory Finishing Process

2012 ◽  
Vol 565 ◽  
pp. 290-295 ◽  
Author(s):  
Prakasam Pradeep Kumar ◽  
Subbiah Sathyan
Keyword(s):  
Material Removal ◽  
Aerospace Industry ◽  
Three Dimensional ◽  
Contact Forces ◽  
Vibratory Finishing ◽  
One Dimensional ◽  
Finishing Process ◽  
Body Dynamics ◽  
The Media ◽  
Multi Body

The vibratory finishing process involves three dimensional motion of abrasive media interacting with part surfaces. With the ultimate goal of simulating such media motion in laboratory conditions, we present here a first step that makes use of a tribometer’s recipricating drive to provide one dimensional controlled vibrations. Finishing experiments using this setup are conducted using abrasive media and titanium alloy work material, both of the type typically used in aerospace industry. Material removal rates, surface roughness and contact forces are measured in two different setups. The media motion is also modelled using multi-body dynamics to predict the contact forces between the media and the work surface. Experimental results are seen to follow literature reported and model predicted trends. This work paves the way for a true three dimensional simulator for a vibratory finishing process.

scholarly journals Influence of different input parameters on the contact conditions determing the surface integrity of workpieces in an unguided vibratory finishing process

Procedia CIRP ◽  
2018 ◽  
Vol 71 ◽  
pp. 53-58 ◽  
Author(s):  
Maximilian Lachenmaier ◽  
Alexander Dehmer ◽  
Daniel Trauth ◽  
Patrick Mattfeld ◽  
Fritz Klocke
Keyword(s):  
Surface Integrity ◽  
Vibratory Finishing ◽  
Contact Conditions ◽  
Finishing Process ◽  
Input Parameters

A Markovian Finishing Process

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
M. A. S. Mohamed
Keyword(s):  
Triangular Form ◽  
Workpiece Surface ◽  
Finishing Process ◽  
Tool Surface ◽  
Markov Matrix ◽  
Abrasive Surface ◽  
Matrix Mapping ◽  
Abrasive Tools ◽  
Finishing Processes ◽  
Abrasive Paper

Addressed is the mechanism of finishing processes for a workpiece surface using hard abrasive tools such as grinding, abrasive paper, and filing. The mechanism is intended to monitor the gradual changes of the workpiece surface state roughness as the tool is applied for several strokes. Based on a number of common features, the present study simulates each rubbing stroke as a Markov process, and each set of several strokes as a Markov chain. In the simulating model, the discrete probabilistic properties of a specific tool abrasive surface can be expressed in terms of a corresponding Markov matrix operator. Thus, the tool action after one rubbing stroke is obtained via a matrix mapping from a given state roughness to a subsequent state roughness of the workpiece surface. Although the suggested model is capable to handle a comprehensive finishing mechanism, the study focuses on the simple case of zero feeding using a hard abrasive tool, in which the Markov matrix shrinks to a special triangular form. Main findings show that major aspects of the tool surface are transferred to the stepwise roughness state of the workpiece immediately after the first stroke. In addition, regardless of the initial roughness state of the workpiece surface, whether with flat or randomly distributed heights, the ultimate state roughness is unique and definitely features the theoretical case of a plain flat surface. However, this theoretical case is infeasible since it can only be reached after infinite number of strokes.

scholarly journals The building performance gap: Are modellers literate?

2017 ◽  
Vol 38 (3) ◽  
pp. 351-375 ◽  
Author(s):  
Salah Imam ◽  
David A Coley ◽  
Ian Walker
Keyword(s):  
Physics Education ◽  
Energy Demand ◽  
Building Performance ◽  
Performance Gap ◽  
The People ◽  
Great Utility ◽  
Input Variables ◽  
Definition Of ◽  
Building Physics ◽  
First Time

One of the most discussed issues in the design community is the performance gap. In this research, we investigate for the first time whether part of the gap might be caused by the modelling literacy of design teams. A total of 108 building modellers were asked to comment on the importance of obtaining and using accurate values for 21 common modelling input variables, from U-values to occupancy schedules when using dynamic simulation to estimate annual energy demand. The questioning was based on a real building for which high-resolution energy, occupancy and temperature data were recorded. A sensitivity analysis was then conducted using a model of the building (based on the measured data) by perturbing one parameter in each simulation. The effect of each perturbation on the annual energy consumption given by the model was found and a ranked list generated. The order of this list was then compared to that given by the modellers for the same changes in the parameters. A correlation analysis indicated little correlation between which variables were thought to be important by the modellers and which proved to be objectively important. k-means cluster analysis identified subgroups of modellers and showed that 25% of the people tested were making judgements that appeared worse than a person responding at random. Follow-up checks showed that higher level qualifications, or having many years of experience in modelling, did not improve the accuracy of people’s predictions. In addition, there was no correlation between modellers, with many ranking some parameters as important that others thought irrelevant. Using a three-part definition of literacy, it is concluded that this sample of modellers, and by implication the population of building modellers, cannot be considered modelling literate. This indicates a new cause of the performance gap. The results suggest a need and an opportunity for both industry and universities to increase their efforts with respect to building physics education, and if this is done, a part of the performance gap could be rapidly closed. Practical application: In any commercial simulation, the modeller will have to decide which parameters must be included and which might be ignored due to lack of time and/or data, and how much any approximations might perturb the results. In this paper, the judgment of 108 modellers was compared against each other. The results show that the internal mental models of thermal modellers disagree with one another, and disagree with the results of a validated thermal model. The lessons learnt will be of great utility to modellers, and those educating the next generation of modellers.

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