Precision Engineering Industries Research Articles

Grinding performance and tribological behavior in solid lubricant assisted grinding of glass-ceramics

High dimensional stability of glass-ceramics is highly attractive to optical and precision engineering industries. This study aims to provide an efficient and stable grinding strategy for realizing high-quality surface and dimensional accuracy of glass-ceramics. The different solid additives (CeO2 and SiC) as lubricants and their performances were investigated regarding the grinding forces, friction coefficient, wheel wear and surface finish during grinding glass-ceramics. Friction and wear mechanism in solid lubricant assisted (SLA) grinding were analyzed. Three-body abrasive wear and chemical mechanical interaction were considered as the predominant lubrication mechanisms. The results showed that the low, stable grinding force and small friction coefficient can be obtained under SLA-SiC grinding. The study proved that the novel strategy can keep the wheel sharpness and improve the process performance.

Aerostatic bearings design and analysis with the application to precision engineering: State-of-the-art and future perspectives

Abstract Aerostatic bearings have been employed as an essential precision engineering element and enabling technology in numerous applications requiring precision and ultraprecision motions. This review paper aims at presenting the state-of-the-art in aerostatic bearings research and development with the emphasis on analytical and computational approaches for design and optimization of bearing performance, and further critically reviewing their future research directions and development trends in the coming decade and beyond. The paper is concluded with the discussion on the future trends and challenges in the aerostatic bearings research, and their applications and potential in precision engineering industries.

Design and Fabrication of a Micro-Capacitor for Nano Probing System

Quantitative dimensional metrologies of Nano/microstructures are increasingly demanded following the rapid developments in, for instance, semiconductor and precision engineering industry, microsystem technology and materials science. In the recent years, coordinate measuring machines (CMMs) have become versatile and widespread metrology tools. Probing system is an important component of a CMM. A probing system based on a high accurate positioning transducer is crucial for micro and nano metrology. This paper presents a probing system based on a variable micro-capacitive transducer which has advantages of simple structure, low cost, high sensitivity, overload ability, excellent dynamic response characteristics, etc. The structure of variable capacitor was designed and optimized by means of finite element method (FEM), and fabricated by surface micromachining technology.

Integrated Production Planning, Scheduling and Shop Floor Tracking System for High-Mix Low-Volume Manufacturing - A Consortium Approach

In Singapore, the Precision Engineering (PE) industry is the backbone of the manufacturing sector; it supports a large number of manufacturing industries such as Electronics, Chemicals, Pharmaceuticals, Biotechnology, Aerospace, Oil & Gas and Automotive. From our recent visits to companies in the PE industry, it was observed that given such a dynamic and stochastic manufacturing environment, most of these PE companies are still predominantly using Microsoft Excel as their planning & scheduling tool, shop floor tracking is normally performed manually through paper traveler, and production status is only updated at the end of the day or as and when demanded by customer. The common problems highlighted include inability to provide realistic delivery commitment, machine and manpower resources are not optimally utilized to fulfill customer orders, unacceptable order cycle time and lack of production visibility. Therefore, there is an increasing demand and impending need for a computerized integrated production planning/scheduling and shop floor tracking system. In this paper, a consortium approach for the development of an integrated production planning/scheduling and shop floor tracking system for the High-Mix Low-Volume (HMLV) PE environment is presented. An illustration through the implementation of the proposed system in a PE company is highlighted. With this system, companies would be able to improve their delivery performance through effective handling of ad-hoc customer orders and the ability to react to deviations or unplanned events in production.

Spin Formability of Al-6061 Aluminum Alloy Pre-Forms Obtained via Liquid Forging

There are growing demands from the precision engineering industries for components that are net or near net shape while striving to reduce material wastage during the manufacturing process. This study investigates the spin formability of liquid forged Al-6061 pre-forms into near net shape cylindrical components with high aspect ratios. The liquid forging process offers very significant materials savings by providing pre-forms for the spin forming process. The end products are near net shape components with very good mechanical properties. Results from this study indicate that liquid forging is able to supply Al-6061 pre-forms, otherwise machined from solid bars, which are sufficiently formable for spin forming. The microstructure of a spin formed liquid forged pre-form is also indiscernible from that of a fully machined pre-form from extruded bar stock. As such, spin forming of liquid forged pre-forms has the potential to reduce material wastage and hence production costs.

Phase Modulation Homodyne Displacement Measuring Interferometer using Tunable Laser Diode as Light Source

Since an ultra precision technology, e.g. a lithography, have been progressing rapidly, displacement measuring methods with resolution of sub-nanometer or less are required. Displacement measuring interferometers are widely utilized in precision engineering industries. However, they suffer from problems of an imperfect interpolation error of nanometer order and an air refractive index fluctuation. In this paper, we propose and discuss a displacement measurement method with no interpolation error by combining a phase modulation homodyne interferometer with a tunable laser diode and the null method. We also discuss the capability to measure the air refractive index fluctuation.

ELID grinding characteristics of glass-ceramic materials

Zerodur glass-ceramic materials have been widely used in optical, opto-electronic and precision engineering industries; their efficient ultraprecision machining, with extremely low surface roughness and high form accuracy, is in great demand in those fields. The authors have been conducting studies on realizing high-quality surface and form accuracy of zerodur glass-ceramic materials efficiently by use of electrolytic in-process dressing (ELID) grinding process. This paper proposes a new grinding mode in which top surface and sides of zerodur block were ground by cylindrical surface and side surface of grinding wheel. Grinding experiments were carried out using #1200, #2000 and #4000 diamond cast-iron bond wheels, and grinding characteristics such as grinding performance, ground surface roughness, surface topographies and perpendicularity between ground surfaces were investigated. Experiments on grinding using #4000 wheel successfully produced smooth top surface and side surfaces that were about 10 nmRa in surface roughness, 1.5 μm/□400×400 mm 2 in flatness and 90°±6″ in perpendicularity. AFM observation of the ground surface also showed that material removal in the ductile mode occurs for fine abrasive wheels. The results showed that grinding was stable without severe clogging for wheels by choosing suitable ELID parameters and grinding conditions.

Case study: meeting the demand for skilled precision engineers

PurposeThis paper aims to demonstrate how science and engineering graduates can be recruited and trained to Masters level in precision engineering as an aid to reducing the skills shortage of mechanical engineers in UK industry.Design/methodology/approachThe paper describes a partnership between three UK academic institutions and industry, creating an Integrated Knowledge Centre (IKC) in Ultra Precision Structured Surfaces. Within this project sits a Knowledge Transfer activity that seeks to channel graduate scientists and engineers through an MSc in “Ultra Precision Technologies” into the UK engineering industry. The creation and implementation of this pipeline, its systems and its processes, is the subject of this paper and its case study.FindingsIn order to retain competitive advantage, the UK precision engineering industry requires a regular supply of technically proficient and organizationally prepared graduates. This paper has explained the approach taken at Cranfield University to increase the size of the pool of postgraduate precision engineers. The approach involves the design of a multi‐level system, which draws on increased connectivity between the University, UK engineering companies, and the student. Academic institutions need to exhibit the appropriate flexibility to meet the demands of industry and the aspirations of the student.Research limitations/implicationsThe paper describes only the early stages of implementation, and further work is necessary.Practical implicationsThe systems model and case studies provide a framework and detail that is of immediate benefit to manufacturing industries and higher education establishments.Originality/valueThe originality of the approach lies in the level of integration between the sub‐systems that comprise the Open system, within which students and skills are forged together in a programme to produce employable engineering postgraduates.

An Interactive Knowledge-Based Multimedia Intelligent Tutoring System for Apprenticeship Training in the Precision Engineering Industry: Implementation of IPD_ITS

We discuss the cognitive aspects of skills training in progressive die design, and the ways to incorporate them into the ITS. We also give an overview of the IPD progressive die design system and explain how the design knowledge base can be exploited for development into an ITS. In this paper, we describe IPD_ITS, the tutoring module of IPD and explain its implementation for burring.

Critical Factors for a Successful Astronomical Research Program in a Developing Country

AbstractI discuss the critical conditions for undertaking a successful research program in a developing country. There are many important factors, all or most of which have to be satisfied: funding, library holdings, computing access, Internet access (e-mail, WWW, ftp, telnet), collaboration with astronomers in developed countries, provision of proper offices for staff, supply of graduate students, access to travel for conferences, ability to publish in international journals, critical mass of researchers, access to a telescope (for observational astronomers), support from and interaction with national electronics, optics and precision engineering industries, a scientific culture backed by a national scientific academy, and lack of inter-institutional rivalry. I make a list of a total of 15 key factors and rank them in order of importance, and discuss the use of an astronomical research index (ARI) suitable for measuring the research potential of a given country or institution.I also discuss whether astronomers in developing countries in principle fare better in a university or in the environment of a government national observatory or research institution, and topics such as the effect of the cost of page charges and journal subscriptions on developing countries. Finally I present some statistics on astronomy in developing countries and relate the numbers of astronomers to the size of the economy and population in each country.

CMEA and COCOM Abolished: Restructuring Precision Engineering Industry in Hungary

The Hungarian precision engineering industry, although fairly successful in the pre-war period and able to survive all the adverse corollaries of planning and CMEA orientation, might be wiped out by the long-awaited marketisation: far more competitive and powerful foreign competitors can now enter both its former single most important market, i.e. the former Soviet Union, and the domestic market. Thus accumulated knowledge of R&D and production engineers as well as the experience of the highly skilled blue-collar workers, albeit of primary importance in this industry, might become completely worthless and disappear. Combined with fresh capital, access to new markets, recent technologies and up-to-date management methods, however, it can (and should) be regarded as a major asset and the indispensable basis for successful restructuring. This paper suggests that sweeping changes in size, ownership, internal organisation, and product range are also inevitable so as to be able to adjust to the new environment.