Journal of Manufacturing Processes Vol. 5/No. 2 2003 163 Study of Airborne Dust Emission and Process Performance During Dry Machining of Aluminum-Silicon Alloy with PCD and CVD Diamond-Coated Tools Prabhu U. Arumugam, Ajay P. Malshe (apm2@engr.uark.edu), Stephen A. Batzer, and Deepak G. Bhat, Materials and Manufacturing Research Laboratories (MRL), Dept. of Mechanical Engineering, University of Arkansas, Fayetteville, Arkansas, USA Abstract The generation of a fine mist of cutting fluid during conven- tional wet machining and the associated environmental and operator health concerns make environmentally benign machin- ing and manufacturing a major research thrust both in the sci- entific and manufacturing communities. In this context, high-speed machining in combination with environmentally be- nign methods makes diamond-coated tooling a unique candi- date for dry machining. Diamond coating research in the past few decades has resulted in new products, one of them being diamond-coated carbide tooling. Diamond in polycrystalline di- amond (PCD), chemical vapor deposited (CVD) thin-film (pol- ished and unpolished) and thick-film forms offers unique advantages for dry machining. This paper presents the correla- tion between diamond tool morphology, machining parameters, nonferrous workpiece properties, and particulate emission in dry machining. These findings provide an important benchmark to gauge the true benefit of diamond tools for dry machining. Keywords: Dry Machining, Diamond-Coated Tools, Environ- mentally Benign Manufacturing Introduction In manufacturing, one of the main growing con- cerns is the environmental impact that arises due to the product, process, or system. The concern for hu- man and ecological health has made the metal cutting industry adopt environmentally friendly manufactur- ing methods. The goal is to improve efficiency, re- duce costs, boost productivity, and minimize the cycle times while simultaneously safeguarding the work en- vironment. The U.S. Occupational Safety & Health Administration (OSHA) is continually proposing new regulations mandating that manufacturers implement environmentally friendly practices. A major concern in the metal cutting industry is the health hazards associated with using cutting fluids in wet machin- ing. Today, it is estimated that more than 100 mil- lion gallons of metalworking fluid are used each year in the United States (NPRA 1991). It also has been estimated that between 700,000 to 1,000,000 work- ers are exposed to cutting fluids in the United States every year (Bennett 1983). Epidemiological studies indicate that long-term exposure to fluids can lead to increased incidence of several types of cancer. The International Agency for Research on Cancer has concluded that there is sufficient evidence that mineral oils used in the workplace are carcinogenic (Raynor et al. 1996). In workplaces, cutting fluids generate fine liquid droplets—mist—that are under 5 microns in diameter. Mist poses a major health threat to machinists (Smolinski et al. 1996) because drops in this range remain airborne for extended pe- riods of time. The alternative for wet machining is dry machining, where no mist is generated and, thus, metal chips are not contaminated by cutting fluids. Dry machining has some challenges, how- ever, such as severe friction at the cutting tool- workpiece interface, restricted chip ejection, and generation of dust particles instead of mist. A general feeling in the machining industry is that dry machining is a viable option in terms of the envi- ronmental hazards over the wet process. This argu- ment is partially supported by the limited research that has been carried out in quantifying the health hazards of wet machining (Mukund et al. 1995) with assumptions such as dry machining generates no re- spirable particles, which is misleading. Another study (Sutherland et al. 2000) concluded that during dry turning of cast iron, all three machining parameters— This paper is an original work and has not been previously published except in the Transactions of NAMRI/SME, Vol. 30, 2002. Journal of Manufacturing Processes Vol. 5/No. 2 2003