Emission of dust in planing and milling of wood

Dust created in the machining of wood is a major problem in the working environment. Minute wood particles carried through the air create a serious health hazard, in extreme cases even leading to cancer. This paper presents the influence of cutting data and tool geometry in reducing dust emissions at the source, i.e. at the tip of the tool. Three different wood materials were investigated; pine, beech and fiberboard (MDF). Specimens were processed in a milling machine where it was possible to alter the cutting data. The dust emissions from the tool (defined here as particles with a diameter less than 10 mu m) were measured. The parameters altered in the experiments were moisture content of the wood, average chip thickness, direction of feed (up or down) and rake angle of the tool. The experiments showed that the average chip thickness had the greatest influence on the amount of dust created when machining wood and the moisture content of the wood a fairly great influence, while the direction of the feed and the rake angle had little or no influence. The results show that dust emissions increase rapidly when reaching a certain average chip thickness (which is the result of the chosen cutting data), It is therefore important to calculate and control the average chip thickness in order to minimize dust emissions from the cutting operation. Furthermore, there is a large difference in dust emissions between the three wood materials tested. Machining MDF creates about six times the amount of dust compared to machining solid pine, When machining beech, the dust emissions are about 50% higher compared to machining pine.