Seamus Gordon

A review of the cutting of composite materials

Abstract The increased use of composite materials has led to an increase in demand for facilities to machine them. There are significant differences between the machining of metals and alloys and that of composite materials, because composites are anisotropic, inhomogeneous and are mostly prepared in laminate form before undergoing the machining process. In most cases, traditional metal cutting tools and techniques are still being used. While the process of metal cutting has been well researched over the years, relatively little research has been carried out on the cutting of composite materials. This paper presents a brief review of research on the cutting of fibre reinforced polymer (FRP) composites and medium-density fibreboard (MDF). Most of the research published is concentrated on the chip formation process and cutting force prediction with unidirectional FRP materials. A review of some recent research on the prediction of cutting forces for MDF is also presented.

Recent research on the machining of wood-based composite materials

Wood-based composite materials are used extensively for interior and exterior construction applications. These materials are typically pressed into sheet form and then machined to the required size and profile. Polycrystalline Diamond (PCD) is the cutting tool material increasingly used to machine these materials. The major benefit of using PCD is extended tool life resulting from its superior properties over traditional tool materials. This paper presents a brief review of the research into the machining of wood-based composites, with particular emphasis on tool wear investigations. Current research work by the authors into PCD tool wear in wood-based composite machining is also outlined. Tool wear modes are proposed for the machining of these materials. It was found that edge honing could improve the wear resistance of the PCD cutting tool.

Student interests and undergraduate performance: the importance of student–course alignment

There has been a growing interest in the influences on undergraduate performance in recent years as a result of the increasing diversity of students entering third-level education and an ever increasing emphasis on the development of a robust knowledge economy. This paper investigates the influence of students’ dominant interest types and prior academic achievement on undergraduate performance in an Irish university. Hollands Self-Directed Search (SDS) interest inventory was completed by 308 students drawn from three, second year undergraduate programmes in engineering, nursing and teaching. The impact of dominant interest types and prior academic achievement on the performance of these students in their second year was then investigated using correlation and linear regression analyses. When combined, student interests and prior academic achievements were found to account for between 38% and 50% of the variance in undergraduate performance for students in these three undergraduate programmes.

Wear Characteristics of PCD when Machining Wood Based Composites

Wood based composite materials are used extensively for interior and exterior construction applications. These materials are typically pressed into sheet form and then machined to the required size and profile. Polycrystalline Diamond (PCD) is the cutting tool material increasingly used to machine these materials. The major benefit of using PCD is extended tool life resulting from its superior properties over traditional tool materials.

Linear Motor based High Speed CNC milling Machine

The traditional approach to constructing CNC machine tools has been to use rotary drive motors and ballscrews to achieve table motion. Linear Motors offer several advantages over this approach, including low inertia, better performance, increased accuracy and reduced complexity. At the University of Limerick a low cost, high speed routing machine was built using linear motors in order to conduct machining tests on a composite material. The machine consisted of a gantry type X/Y motion system on which a high speed electrospindle was mounted. Both were interfaced with a standalone CNC controller for which a Microsoft Windows based interface was written in C++. The machine has the usual functionality of a CNC router and is capable of table speeds of over 25 m/min, with a spindle speed of 30,000 rev/min. The machine is at present being used to carry out tests on tool wear as part of an ongoing research project in the University.