Modelling of airborne dust emissions in CNC MDF milling

Abstract

All dust control measures are necessary to reduce dust exposure in MDF (Medium Density Fibreboard)-milling, because of the high amount and fineness of the dust produced and a potential risk of exposure to formaldehyde or other glue chemicals during the machining of MDF. The most effective way of reducing dust exposure is to reduce the emission of dust at the source. Airborne dust emission was studied and modelled in the milling. In the milling of MDF, airborne dust emission was much higher than in the milling of solid materials. Milling of MDF produced airborne particles with a mass median diameter of 6–7 µm. The most significant factor affecting the amount of dust created from milling was average chip thickness. In order to reduce the amount of dust, milling parameters should be chosen so that the average chip thickness is greater than 0.05 mm. The average chip thickness could be obtained with different milling parameters, for example with different combinations of feed and traverse rates. The same chip thicknesses resulted in around the same percentage fraction of fine dust mass regardless of how the average chip thickness was obtained. The relationship between the percentage fraction of fine dust mass from the removed mass (c%) and the chip thickness (hm) was modelled and presented in the form of c% = 0.194 h m -1. The model developed can be used to estimate the percentage fraction of fine dust mass as a function of chip thickness. The model can be used in optimisation programs for CNC milling machines to minimize the airborne dust generated and to reduce dust exposure.