On Force-Displacement Characteristics and Surface Deformation in Piezo Vibration Striking Treatment (PVST)

2021 ◽  
pp. 1-27
Author(s):  
Jisheng Chen ◽  
Yang Xu ◽  
Juan Sandoval ◽  
Patrick Kwon ◽  
Yang Guo
Keyword(s):  
Surface Deformation ◽  
Resonant Mode ◽  
Cnc Machine ◽  
Vibration Displacement ◽  
Workpiece Surface ◽  
Tool Vibration ◽  
Tool Surface ◽  
Linear Force ◽  
Force Displacement ◽  
Mechanical Surface

Abstract This paper presents an experimental study on a novel mechanical surface treatment process, namely piezo vibration striking treatment (PVST), which is realized by a piezo stack vibration device installed on a CNC machine. Unlike other striking-based surface treatments, PVST employs non-resonant mode piezo vibration to induce controllable tool strikes on workpiece surface. In this study, an experimental setup of PVST is implemented. Four types of experiments, i.e., tool-surface approaching, single-spot striking, 1D scan striking, and 2D scan striking, are conducted to investigate the relationships among the striking force, tool vibration displacement, and surface deformation in PVST. The study shows that PVST can induce strikes with consistent intensity in each cycle of tool vibration. Both the striking intensity and striking location can be well controlled. Such process capability is particularly demonstrated by the resulting texture and roughness of the treated surfaces. Moreover, two linear force relationships have been found in PVST. The first linear relationship is between the striking force and the reduction in vibration amplitude during striking. The second one is between the striking force and the permanent indentation depth created by the strike. These linear force relationships offer the opportunity to realize real-time monitoring and force-based feedback control of PVST. This study is the first step towards developing PVST as a more efficient deformation-based surface modification process.

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.

Tool Surface Topographies for Controlling Friction and Wear in Metal-Forming Processes

1998 ◽  
Vol 120 (3) ◽  
pp. 517-527 ◽  
Author(s):  
Simon Sheu ◽  
Louis G. Hector ◽  
Owen Richmond
Keyword(s):  
Surface Topography ◽  
Metal Forming ◽  
Friction And Wear ◽  
Workpiece Surface ◽  
Bulk Metal ◽  
Bulk Metal Forming ◽  
Single Scale ◽  
Surface Topographies ◽  
Tool Surface ◽  
Scale Surface

A conceptual framework is introduced for the design of tool surface topographies in bulk metal forming processes. The objective of the design is to control friction to desired levels while minimizing wear of the workpiece and tool surfaces and adhesive metal transfer between the workpiece and tool. Central to the design framework are the tool/workpiece interface properties of lubricant retention and interface permeability. Lubricant retention refers to the capacity of an interface to retain lubricant rather than freely channel it to the exterior of the tool/workpiece conjunction. Permeability refers to the capacity to distribute lubricant to all areas within the conjunction. These properties lead to the concept of two-scale surface topography consisting of a fine scale background of interconnected channels on which is superimposed an array of coarser-scale cavities. Control of friction and wear is achieved by designing the tool surface topographies at these two scales to address the unique tribological conditions of specific bulk metal forming processes. The coarser scale is designed to ensure adequate supply of lubricant within the conjunction. The finer scale is designed to ensure adequate delivery of lubricant to all parts of the conjunction where nascent workpiece surface is being formed. The design concepts are illustrated with results from laboratory experiments using the rolling process as an example, and comparing the performance of various roll surface topographies under similar processing conditions. A two-scale surface topography consisting of hemispherical cavities distributed across a background surface of finer scale, interconnected channels was shown to reduce friction compared to a single-scale ground finish, but not as much as a single-scale coarse topography consisting of densely-packed cavities produced by an electrical discharge treatment. On the other hand, the smoother cross-sections of the cavities, especially when elongated in the direction of greatest relative motion, produced significantly less wear than either of the single-scale tool surface treatments. It is concluded that two-scale engineering of tool surface topographies based upon the concepts of lubricant retention and interface permeability can provide a broad basis for achieving desired levels of interface friction while minimizing workpiece surface wear and adhesive material transfer in many metal-forming processes.

The Effect of 5 Mechanical Gaming Keyboard Key Switch Profiles on Typing and Gaming Muscle Activity, Performance and Preferences

2018 ◽  
Vol 62 (1) ◽  
pp. 1552-1556
Author(s):  
Charles Miller ◽  
Alan Barr ◽  
Raziel Riemer ◽  
Carisa Harris
Keyword(s):  
Task Performance ◽  
Muscle Activity ◽  
Word Processing ◽  
Tactile Feedback ◽  
User Preference ◽  
Displacement Curve ◽  
Study Task ◽  
Activity Performance ◽  
Linear Force ◽  
Force Displacement

Introduction:Single force-displacement characteristics of mechanical key switches have been shown to affect performance, fatigue and discomfort during keyboard use. This study compared the effects of mechanical key switches with differing force-displacement characteristics on forearm muscle activity, typing performance, Fitts Study task performance, subjective fatigue and user preference. Methods: Using a within subjects intervention study of crossover design, 64 subjects completed modified Fitts and typing tasks on five different mechanical key switches to mimic dual word processing and gaming keyboard use. Bilateral muscle activity was recorded using surface electromyography (EMG); typing and Fitts task performance measures were tracked. Results: The key switch with a linear force displacement curve had higher net strokes and lower net typing speed than two key switches with tactile feedback (p<0.05). The key switch with the longest tactile travel, operating travel and highest bottom force required slightly higher peak muscle activity compared to 2 other key switches with lower values (p<0.05). Key switches with shorter tactile and operating travel and lower bottom forces were preferred over other key switches.Conclusions: Among mechanical key switches, a linear force displacement curve had the worst outcomes; key switches with shorter tactile (1.2mm) and operating travel (2.0mm) and a lower bottom force (35-40g) had best outcomes overall.

scholarly journals On-demand release of Candida albicans biofilms from urinary catheters by mechanical surface deformation

Biofouling ◽  
2018 ◽  
Vol 34 (6) ◽  
pp. 595-604 ◽  
Author(s):  
Stacey A. Maskarinec ◽  
Zehra Parlak ◽  
Qing Tu ◽  
Vrad Levering ◽  
Stefan Zauscher ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Surface Deformation ◽  
Urinary Catheters ◽  
On Demand ◽  
Candida Albicans Biofilms ◽  
Mechanical Surface

Study on the Double Pulse Laser Dynamic Electronic Speckle Measurement Based on FPGA

2014 ◽  
Vol 900 ◽  
pp. 617-622
Author(s):  
Fu Sheng Yu ◽  
Teng Fei Li ◽  
Yan Chao Wu ◽  
Zhong Guo Sun ◽  
Sheng Jiang Yin
Keyword(s):  
Stress Distribution ◽  
High Speed ◽  
Surface Deformation ◽  
Speckle Pattern ◽  
Dynamic Measurement ◽  
High Accuracy ◽  
Laser Speckle ◽  
Tool Surface ◽  
Milling Tools ◽  
Intermittent Cutting

Speckle pattern interferometry can be used to measure he displacement, strain and vibration, surface deformation and surface roughness. And dynamic laser speckle measurement with high accuracy has been widely used in measurement of surface deformation. Tool breakage is the main bottleneck of high-speed intermittent cutting development, therefore, obtaining stress distribution of milling tools is a base of improving the tool design and tool life. Using a speckle measurement method of double pulsed digital based on FPGA, which involves the laser cutter, tools and CCD, transforms the high-speed dynamic measurement to quasi-static measurement. As a result, we can get two speckle images of front and back milling cutter surface and calculate the deformation ,strain and stress distribution of the tool surface with analysis.

Improved nonlinear model of a yaw damper for simulating the dynamics of a high-speed train

2018 ◽  
Vol 233 (7) ◽  
pp. 651-665 ◽  
Author(s):  
Wanxiu Teng ◽  
Huailong Shi ◽  
Ren Luo ◽  
Jing Zeng ◽  
Caihong Huang
Keyword(s):  
Nonlinear Model ◽  
High Speed ◽  
Piecewise Linear ◽  
Excitation Frequency ◽  
Maxwell Model ◽  
Railway Vehicle ◽  
High Speed Train ◽  
Force Velocity ◽  
Linear Force ◽  
Force Displacement

The aim of this paper is to establish a simple and accurate nonlinear model of a yaw damper for the dynamic numerical simulation of high-speed trains. An improved nonlinear yaw damper model is proposed based on the traditional Maxwell model. It comprises a piecewise linear force–displacement spring and a piecewise linear force–velocity damper in series. These nonlinear inputs for the model are retrieved from the dynamic performance tests of the damper, and the force–displacement and force–velocity curves are further modified to improve the modelling accuracy according to the test results. The proposed model can accurately simulate the damper's dynamic stiffness and dynamic damping characteristics with respect to the excitation frequency or displacement, which cannot be reproduced when using the traditional Maxwell model. Both the traditional Maxwell model and the improved nonlinear model presented in this work are integrated into a multibody dynamics railway vehicle model to simulate the typical dynamic problems of a high-speed train operating at 250 km/h in northeast China. Through comparative analysis, it was found that the numerical simulations are consistent with the field measurements. It can be concluded that the proposed nonlinear damper model is more suitable for studying railway vehicle system dynamics under various operating cases. By contrast, the input parameters of the traditional Maxwell model must be modified artificially according to the vehicle responses and the dynamic characteristics of the yaw damper.

Development of a Multi-Ball-Cantilever AFM for Measuring Resist Surface

2006 ◽  
Vol 18 (6) ◽  
pp. 698-704 ◽  
Author(s):  
Shujie Liu ◽  
◽  
Shuichi Nagasawa ◽  
Satoru Takahashi ◽  
Kiyoshi Takamasu
Keyword(s):  
High Speed ◽  
Surface Deformation ◽  
Surface Profile ◽  
Displacement Curve ◽  
The Finite Element Method ◽  
Measuring Surface ◽  
Surface Profiles ◽  
Relationship Of ◽  
The Relationship ◽  
Force Displacement

Semiconductor processing must be fast and highly accurate when measuring the surface profile of soft thin films such as photoresists. We propose doing so using a multi-ball-cantilever AFM, which covers a wide area at high speed. Each cantilever has a ball stylus with a diameter that does not plastically deform measured surfaces. We studied resist profiles and the influence of the AFM stylus on the resist surface. To verify our proposal’s feasibility, we simulated the relationship of the indenter shape, size, and load and resist surface deformation using the finite element method (FEM). We discuss the influence of the AFM stylus based on the force-displacement curve. Experiments using the multi-ball-cantilever AFM confirmed its feasibility for measuring surface profiles highly accurately.

Influence of Machined Workpiece Surface Integrity on Fatigue Performance

2013 ◽  
Vol 373-375 ◽  
pp. 1999-2003
Author(s):  
Shun Xi Gao ◽  
Qing Liang Zhang
Keyword(s):  
Surface Topography ◽  
Surface Integrity ◽  
Surface Layers ◽  
Average Roughness ◽  
Plastic Deformations ◽  
Workpiece Surface ◽  
Arithmetic Average ◽  
Defect Area ◽  
Fatigue Endurance ◽  
Mechanical Surface

The effect of machined workpiece surface topography and surface integrity were studied. Modifications of surface layers after mechanical surface treatments were also reviewed. Conflict ideas exist in publications about which parameters can better define fatigue endurance. The traditional one was Arithmetic Average Roughness, although deepest surface feature and the square root of the defect area were proposed. The combinations of these factors including high temperature, metallurgical alternations and plastic deformations, rather than the residual stress alone affect surface topography and surface integrity. They should be examined carefully in order to gain a better understanding of fatigue.

Research on Accuracy Analysis and Simulation for Typical Parts with PRS-XY NC Hybrid PMT

2010 ◽  
Vol 148-149 ◽  
pp. 299-303
Author(s):  
Yue Peng Chen ◽  
Hong Wei Fu ◽  
Biao Wang
Keyword(s):  
Inverse Kinematics ◽  
Simulation Software ◽  
Process Models ◽  
Accuracy Analysis ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Error Sources ◽  
Kinematics Model ◽  
Main Error ◽  
Tool Surface

The paper presented a set of PRS-XY hybrid PMT, made up of a set of 3-PRS parallel mechanism and an X-Y table. For advancing the motion accuracy of the PRS-XY type hybrid CNC machine tool, the forward kinematics model and inverse kinematics model have been made, and main error sources affect to machine tool’s precision was established. The relative position of workpiece and the tool of PRS-XY PMT wad discussed, and the coordinate of tool surface was calculated in various process models. The chamfer shape with variation of main error sources was drawn in simulation software, and the processing experiment results prove the correctness of analysis and simulation.

Sign in / Sign up

Export Citation Format

Share Document