Analysis of Aerosol Emission and Hazard Evaluation of Electrical Discharge Machining (EDM) Process

Abstract

The safety and environmental aspects of a manufacturing process are important due to increased environmental regulations and life quality. In this paper, the concentration of aerosols in the breathing zone of the operator of Electrical Discharge Machining (EDM), a commonly used non traditional manufacturing process is presented. The pattern of aerosol emissions from this process with varying process parameters such as peak current, pulse duration, dielectric flushing pressure and the level of dielectric was evaluated. Further, the HAZOP technique was employed to identify the inherent safety aspects and fire risk of the EDM process under different working conditions. The analysis of aerosol exposure showed that the concentration of aerosol was increased with increase in the peak current, pulse duration and dielectric level and was decreased with increase in the flushing pressure. It was also found that at higher values of peak current (7A) and pulse duration (520 m s), the concentration of aerosols at breathing zone of the operator was above the permissible exposure limit value for respirable particulates (5 mg/m 3 ). HAZOP study of the EDM process showed that this process is vulnerable to fire and explosion hazards. A detailed discussion on preventing the fire and explosion hazard is presented in this paper. The emission and risk of fire of the EDM process can be minimized by selecting proper process parameters and employing appropriate control strategy.

Airborne Nanoparticle Pollution in a Wire Electrical Discharge Machining Workshop and Potential Health Risks

“…However, health risks associated with EDM air pollution are not yet clearly understood (Andujar et al, 2014). Jose et al (2010) evaluated the aerosol exposure of DEDM and showed that the aerosol concentration at breathing zone of the operator was above the permissible limit for repairable particulates (5 mg/m 3 ). Unfortunately, no size fraction information was reported.…”

Assessing the effects of different dielectrics on environmentally conscious powder-mixed EDM of difficult-to-machine material (WC-Co)

“…[23,24], environmental factors, such as aerosol concentration and dielectric consumption, require immediate attention.…”

“…To identify scenarios that would lead to the release of hazardous or flammable material into the atmosphere, consequently exposing workers to injury; D. To check the safety of the design; E. To improve the safety of an existing and/or modified facility. The process of performing HAZOP analysis [23] is based on three steps, as shown in Fig. 6.…”

“…Several researchers, such as Jeswani [12], Wong et al [13], Kumar et al [14], and Han et al [15] used graphite powder for EDM of DTM materials and found it significantly useful. This process assisted us in selecting the graphite powder as abrasive in EDM of WC-Co. Table 1 [3,[17][18][19][20][21][22][23][24][25][26][27][28] describes the work done and gaps in literature with respect to EDM of WC. Jeswani [12] investigated EDM with distilled water and kerosene oil as dielectric fluid.…”

“…Many studies have reported on the production and related aspects of the EDM process, but only a few studies [22][23][24][25][26][27] that considered the environmental, safety, and health hazards of the EDM process were undertaken. Furthermore, studies presented in the literature focused on the effects of a single dielectric fluid, namely, kerosene oil; no study has investigated the effects of different dielectric fluids, especially water-based dielectric fluids for the EDM process.…”