Surface Roughness Analysis on Sheet Metals During AWJ Machining Using Low Pressure

The present study discusses the effect of abrasive waterjet machining (AWJ) parameters on surface roughness during cutting of sheets metals of stainless steel 304 and pure copper. A relatively low hydraulic pressure below 150 MPa was used. Several machining parameters were chosen namely pressure, traverse rate, stand-off distance and abrasive mass flowrate. It was found that increasing the pressure leads to an increase in the surface roughness. Varying other parameters did not clearly show any trends on the surface roughness. A higher surface roughness happened during AWJ machining of stainless steel 304 compared to pure copper due to its former higher hardness. The surface roughness at the upper region closer to the top surface is higher than the bottom section regardless of machining parameters. Furthermore, embedded particles are more dominant in pure copper than stainless steels 304. It can be concluded that a low water pressure in AWJ machining process can be used to cut sheet metals successfully with acceptable cutting quality

Prediction of abrasive waterjet machining of sheet metals using artificial neural network

High pressure waterjet technology has received a wider acceptance for various applications involving machining, cleaning, surface treatment and material cutting. Machining of soft and thin materials with acceptable cutting quality requires a relatively low waterjet pump capacity typically below 150 MPa. The present study attempts to predict the surface roughness during the waterjet machining process for a successful cutting of sheet metals using low pressure. Artificial neural network model was used as the method for prediction. Taguchi method with L36 orthogonal array was employed to develop the experimental design. A back-propagation algorithm used in the ANN model has successfully predicted the surface roughness with the mean squared error to be below 10%. This summarizes that ANN model can sufficiently estimate surface roughness in the abrasive waterjet machining of sheet metals with a reasonable error range

Analysis of unimorph piezoceramic patches on damped square shaped plate

Active damping using piezoelectric element is one of the effective techniques to counter vibration problems. A 3D finite-element model is developed as part of investigation for damping control. The piezoelectric patches are surface bonded on quadrilateral thin plate and supported with spring damper elements. The main goal of this paper is to investigate mechanical characteristics of piezoceramic array on membrane and the effect of force excitation using small motor and electric excitation on the system. The system setup produced small vibration displacement and does not displace the plate beyond elastic strain region. The results show the linear behavior of piezoceramic and the correlation between electric excitation, motor vibration and displacement at the centre of the plate at different frequency range. The mode shapes and natural frequencies at low frequency spectrum are also presented. Therefore, the results can be used as reference to develop damping system with aid of piezoelectric patches

Mechanical properties of oil palm waste lightweight aggregate concrete with fly ash as fine aggregate replacement

Environmental degradation posed by fly ash (FA) disposal from coal power plants and shell from the oil palm fruit processing trade is non-trivial. The destruction of flora and fauna resulting from the extraction of river sand and granite aggregate from the green hills in an uncontrolled fashion for the production of concrete that is widely used in the construction industry does also require a solution. Introducing oil palm shell (OPS) and fly ash as a mixing ingredient in zero granite lightweight aggregate concrete production is an appealing notion. Success in utilising the available solid waste would reduce dumping of these by-products and consumption of natural aggregates, thus ensuring the preservation of the environment for the future generation. Therefore, this research explores the influence of FA content as sand replacement towards the mechanical and durability properties of agro-based lightweight concrete. Five concrete mixes with FA quantity ranging from 0% to 40% were prepared. Two forms of curing procedure were practised viz. water and indoor air curing. All the mixes were tested for fresh and hardened characteristic as well as sulphate resistance. The test results demonstrated that a substitution of 10% sand with FA yielded better mechanical properties and denser concrete with more resistant to sulphate attack in comparison to the control mix. The utilisation of two industrial waste materials such as FA and OPS may address the issue of paucity of natural resources that is experienced in the construction industry, particularly in the case of natural granite and river sand

Motion Synthesis Of Planar Four Linkage Movement For Part Flipping Application

Designs methods for four linkages encompass mathematical approach, trial and error method, function generation, motion synthesis and path synthesis. Various literatures found used mathematical approach to find specific solution. This main goal of this paper is to provide study of motion synthesis of four bar mechanism to find solution for mobile parts flipping application. Systematic procedures for motion synthesis to determine the length and position of the links in case of desired positions of a coupler are presented. The graphical method provides quick solution for designer regarding kinematic problem without involvement of complicated mathematical equation. Part of the solution is compared with mathematical approach and simulation approach. As a conclusion, the graphicaI approach result match with other method and helpful to provide better insight of the system during designing the solution

Analysis of acoustic emission during abrasive waterjet machining of sheet metals

The present paper reports on the analysis of acoustic emission (AE) produced during abrasive waterjet (AWJ) machining process. This paper focuses on the relationship of AE and surface quality of sheet metals. The changes in acoustic emission signals recorded by the mean of power spectral density (PSD) via covariance method in relation to the surface quality of the cut are discussed. The test was made using two materials for comparison namely aluminium 6061 and stainless steel 304 with five different feed rates. The acoustic emission data were captured by Labview and later processed using MATLAB software. The results show that the AE spectrums correlated with different feed rates and surface qualities. It can be concluded that the AE is capable of monitoring the changes of feed rate and surface quality

Analysis of unimorph piezoceramic patches on damped square shaped plate

Active damping using piezoelectric element is one of the effective techniques to counter vibration problems. A 3D finite-element model is developed as part of investigation for damping control. The piezoelectric patches are surface bonded on quadrilateral thin plate and supported with spring damper elements. The main goal of this paper is to investigate mechanical characteristics of piezoceramic array on membrane and the effect of force excitation using small motor and electric excitation on the system. The system setup produced small vibration displacement and does not displace the plate beyond elastic strain region. The results show the linear behavior of piezoceramic and the correlation between electric excitation, motor vibration and displacement at the centre of the plate at different frequency range. The mode shapes and natural frequencies at low frequency spectrum are also presented. Therefore, the results can be used as reference to develop damping system with aid of piezoelectric patches

MOTION SYNTHESIS OF PLANAR FOUR LINKAGE MOVEMENT FOR PART FLIPPING APPLICATION

Design methods for four linkages encompass mathematical approach, trial and error method, function generation, motion synthesis and path synthesis. Various literatures found used mathematical approach to find specific solution. The main goal of this paper is to provide study of motion synthesis of four bar mechanism to find solution for mobile part flipping application. Systematic procedures for motion synthesis to determine the length and position of the links in case of desired positions of a coupler are presented. The graphical method provides quick solution for designer regarding kinematic problem without involvement of complicated mathematical equation. Part of the solution is compared with mathematical approach and simulation approach. The graphical approach result matches with other method and helpful to provide better insight of the system during designing the solution