Investigation of factors affecting the learning of final year advanced materials and manufacturing students

An investigation was recently conducted into the delivery of an Advanced Materials and Manufacturing Processes module which was presented to a sub-group of the final year engineering students at Dublin City University (DCU). Results from the class which has just completed their final year studies were examined in relation to the method of delivery. This cohort consisted of 25 students, 13 which studied for the Computer Aided Mechanical and Manufacturing Engineering (CAM) degree and 12 which studied for the Business and Manufacturing Engineering (BME) degree. This paper presents an examination of some of the factors affecting the overall results of these students. Factors evaluated include attendance of the student, as well as individual performance in continuous assessment and examination. Overall attendance at the lecture, the organised seminar series, and practical work were recorded. Results indicate a direct link between attendance and marks awarded. Students with higher attendance achieved better grades. Good continuous assessment performance did not automatically indicate good exam performance. Contrary evidence to this is discussed in relation to student learning styles where students may show better ability in exams with poorer ability in continuous assessment and vice versa

Laser surface modification of Ti-6Al-4V for biomedical applications

Introduction. Ti-6Al-4V is used in biomedical engineering due to its excellent properties: high strength to weight ratio, low density, high corrosion resistance and good biocompatibility. However, the use of the alloy under severe friction conditions is restricted due to poor tribological properties such as high coefficient of friction and low hardness [1, 2]. Laser surface modification is known for its improved mechanical and tribological properties for biomedical titanium alloys. The treatment produces minimal contamination and increases osseointegration [3-5]. The present study evaluated the effects of high speed, laser processing parameters on surface roughness, hardness, chemical composition and biocompatibility. Materials and Methods A 1.5KW CO2 laser in continuous mode was irradiated on flat Ti-6Al-4V samples at three levels of irradiance 15.72, 20.43 and 26.72 KW/cm2 and three levels of residence time 1.08, 1.44 and 2.16 ms. Evaluation of the surface was carried out by scanning electron microscope (SEM) examination and mechanical profilometry in accordance to ISO 4287/4288. SEM analysis of the surface topography resulting from the various laser treatments was carried out. Energy Dispersive Spectroscopy (EDS) analysis was used to determine the chemical composition of the treated areas. The effect of surface topography on cellular attachment was investigated in vitro using MC3T3-E1 pre-osteoblast cells. Cell attachment was determined using the Hoechst DNA assay and cell morphology was examined using SEM analysis. Results and Discussion An increase in residence time resulted in improved depth of processing. An increase in irradiance did not always produce an increase in depth of processing; however higher irradiance levels were found to provide for a more uniform depth of processing which reached a maximum of 80 µm. Irradiation with the scanning beam produced a single phase microstructure, see Figure 1. This single phase occurred when various constituents in the alloy have dissolved with rapid solidification thwarting segregation of the various alloying elements into high and low concentration [6]. Improved homogenous chemical composition of the laser modified region was verified by the EDS analysis. Microhardness examination revealed an increase in hardness of up to 67% after laser treatment. A relationship between irradiance and roughness was observed, roughness decreasing with increase in irradiance

Affects of student attendance on performance in undergraduate materials and manufacturing modules

This paper investigates the class attendance of second year, third year and fourth year students and their overall performance at the school of Mechanical and Manufacturing Engineering in Dublin City University (DCU). An investigation was recently conducted into the delivery of different module which was presented to a group of second year, third year and fourth year engineering students at DCU. Attendance in the class was recorded and the continuous assessment results and the final overall performances were investigated with their attendance. Student performance on Strength of materials – part 1 (SM1), Strength of materials part - 2 (SM2), Mechanics of Materials and Machine (MMM) and Advanced Materials and Manufacturing Processes (AMMP) modules are presented in this paper. This paper presents an examination of some of the factors affecting the overall results of these students. Factors evaluated include attendance of the student, as well as individual performance in continuous assessment and examination. Overall attendance at the lecture, the organised seminar series, and practical work were recorded. Results indicate a direct link between attendance and marks awarded. Students with higher attendance achieved better grades

Employer and student perspectives on skills for engineers in the twenty first century and beyond

This research focused on skills identified among final year engineering students. It provided evidence of different levels of skills by students and identifies their greatest learning influences in these areas. The skills were self-assessed by students and covered seven areas designated by Engineers Ireland. Competency levels such as science, software, creativity, engineering practice, social and business, ethics, discipline specific were assessed. It also investigated the important role that work placements play in skills developed by students. Key skills sought by leading Engineering firms from graduates now and in the next five years were also researched in this paper. Employers were surveyed to determine and investigate skills needed from graduate engineers and how best to meet these challenges. The emphasis on work placements and its impact on skills’ development in engineering students such as business acumen and working effectively and efficiently in industry were highlighted

Designing pulse laser surface modification of H13 steel using response surface method

This paper presents a design of experiment (DOE) for laser surface modification process of AISI H13 tool steel in achieving the maximum hardness and minimum surface roughness at a range of modified layer depth. A Rofin DC-015 diffusion-cooled CO2 slab laser was used to process AISI H13 tool steel samples. Samples of 10 mm diameter were sectioned to 100 mm length in order to process a predefined circumferential area. The parameters selected for examination were laser peak power, overlap percentage and pulse repetition frequency (PRF). The response surface method with Box-Behnken design approach in Design Expert 7 software was used to design the H13 laser surface modification process. Metallographic study and image analysis were done to measure the modified layer depth. The modified surface roughness was measured using two-dimensional surface profilometer. The correlation of the three laser processing parameters and the modified surface properties was specified by plotting three-dimensional graph. The hardness properties were tested at 981 mN force. From metallographic study, the laser modified surface depth was between 37 8m and 150 8m. The average surface roughness recorded from the 2D profilometry was at a minimum value of 1.8 8m. The maximum hardness achieved was between 728 and 905 HV0.1.These findings are significant to modern development of hard coatings for wear resistant applications

Examination of the stir-casting method to produce Al-SiC composites

This work examined the influence of processing parameters on the production of Al-SiC metal matrix composites (MMC) by batch compocasting process. Processing parameters investigated includes tirring speed, stirring time, stirrer geometry, stirrer position , metal fluid temperature (viscosity). Room temperature (25°C) visual simulations, computer simulations and validation Al-SiC MMC production tests were performed. In the visual and computer simulations, water an d g ly c e ro l/water were used to represent liquid an d semi-solid a lum in ium respectively. The effects of viscosities of 1, 300, 500, 800 and 1000 mPas and stirrin g speeds of 50, 100, 150, 200, 250 and 300 rpm were investigated. A 10 vol. % reinforced SiC particulate , similar to that used in the aluminium MMC’s, was used in the visualisation and computational tests. The visualisation tests were carried out in a transparent glass beaker. The computational simulation was performed with Fluent(CFD software) an d an ad d on package MixSim. This consisted of a 2D axisym metric multip h a se time dependent simulation of the production routeusing an Eulerian (granular) model. The dependence of particle dispersion times, settling timesand vortex height on stirring geometry and stirrer speed was found. A blade angle of 60 degrees was found better for the flat blade stirrer, to obtain uniform particulate dispersions quickly. From the setestsas tirrin g speed of 150 rpm for water-SiC an d 300 rpm for the glycerol/water-S iC sy stem were found to be necessary in order to obtain a uniformd is tribution of the SiC. A viscosity increase from 1 mPas (for liquid metal) to 300 m Pas (for semi-solid metal) was found to have a tremendous effect on the SiC dispersion and settling times. However, a further increase from 300 mPas to 1000 mPashad negligible effect on this time. A significant part of the work consisted of the design, construction and validation of a specialised quick quench compocaster for this high temperature processing method. This machine consisted of a stirrer with four 60 degree angled flat blades and a cruciblein a resistance heated furnace chamber. An actuator was integrated to this rig to enable quick quenching of the processed mixture. This device was used to produce Al-SiC composites. Generally, good agreement was found between the visualisation, computational and validation experimental results

Development of a heat transfer and artificial neural networks teaching laboratory practical for biotechnology students

The paper describes a newly developed laboratory practical that teaches students how to develop an Artificial Neural Network model and its possible use in bio-processing. An emphasis is placed on giving students "hands on" experience with bio-processing equipment, namely bio-reactors and data acquisition systems in an attempt to help prepare them for work in bio-processing and chemical engineering industries

Analysis of international graduate programmes structures for engineering education

This article traces the evolution of graduate study in Engineering in Ireland over three decades. Very few studies have shown the different norms and structures of graduate programmes in Ireland. In this paper, a review of traditional and structured PhD in terms of credit requirements and co-ordination structures is presented. The authors summarise the characteristics of graduate programmes in different universities in Ireland and compare these to those obtained in some of the leading international universities. The implementation of graduate programmes in Ireland is relatively recent and the structure of these programmes is still under development in the different universities. Plans for enhancement of graduate programs and the development of new initiatives to support graduate student academic and professional development are very important for the success of these programmes. The growth in enrolment reflects a broad diversity in background of students which will require not only increased financial resources but an adequate and sound organisational structure in order to move forward

An overview of laser surface modification of die steels

In recent years, surface modification using advanced heat source like laser has been replacing the conventional methods to produce amorphous microstructure via rapid solidification. Due to the benefits of laser to enhance the tribological and mechanical properties of materials’ surface, several laser surface processing were developed including laser surface modification, namely laser alloying, transformation hardening, surface amorphization, shock hardening and glazing. In high temperature applications, the laser surface modification technique is beneficial to prolong the die life cycle, and also to improve the surface roughness of thermal barrier coatings (TBC). To produce the amorphous layer at a particular depth, laser parameter such as irradiance, frequency, and exposure time are controlled. Variations of parameter may result in modified microhardness properties of heat affected zone and transition zone. Nevertheless, works on laser glazing of bearings, railroad rails and TBC had proven the surface properties were enhanced through laser glazing to cope with excessive load, wear, fatigue, bending and friction demand

Spinodal decomposition in AISI 316L stainless steel via high-speedlaser remelting

A 1.5 kW CO2 pulsed laser was used to melt the surface of AISI 316L stainless steel with a view to enhancing the surface properties for engineering applications. A 90 m laser beam spot size focused onto the surface was used to provide high irradiances (up to 23.56MW/cm2) with low residence times (as low as 50 s) in order to induce rapid surface melting and solidification. Variations in microstructure at different points within the laser treated region were investigated. From this processing refined lamellar and nodular microstructures were produced. These sets of unique microstructures were produced within the remelted region when the highest energy densities were selected in conjunction with the lowest residence times. The transformation from the typical austenitic structure to much finer unique lamellar and nodular structures was attributed to the high thermal gradients achieved using these selected laser processing parameters. These structures resulted in unique characteristics including elimination of cracks and a reduction of inclusions within the treated region. Grain structure reorientation between the bulk alloy and laser-treated region occurred due to the induced thermal gradients. This present article reports on microstructure forms resulting from the high-speed laser surface remelting and corresponding underlying kinetics