Research On Wooden Dust In Milling Of Medium Density Fiberboard

The generation of dust is inevitable in the milling process of fiberboard.Dust is not only a threat to the health of workers,but also may cause dust explosion.Therefore,it is necessary for wood processing enterprises to reduce the dust generation.Wooden dust is affected by cutting parameters,cutting tools,moisture content and density of wood.Up to now,there are few literatures about the influence of cutting parameters on the cutting dust of MDF,most of them are about the solid wood or metal dust,the dust concentration is mostly about PM10,and the research on TSP is less.This study is expected to reduce the dust generation by changing the cutting parameters,and provide a theoretical basis for the arrangement of dust removal system.In this paper,MDF is used as cutting material,and wood CNC machining center is used to mill MDF.The effects of different cutting parameters(milling depth,feed speed,spindle speed)on dust concentration,dust production and dust particle size distribution are studied.The dust concentration prediction model is established by regression analysis.In addition,the dust mobility of MDF is studied.The results are as follows:(1)In the study of MDF dust fluidity,firstly,the particle size of fiberboard dust is classified,then,to study the fluidity of different particle size dust.The results show that the fluidity of MDF dust belongs to the powder with poor fluidity,and its fluidity is poor with the decrease of dust particle size.When the dust particle size is above 97 ? m,the fluidity of the dust is general.When the dust particle size is below 97 ? m,the fluidity of the dust is poor.(2)In the study of the influence of various parameters on the dust concentration distribution in MDF milling process,the milling depth,feed speed and spindle speed are set as a single variable to study the dust concentration distribution in the cutting plane.The results show that in the range of cutting parameters,the dust concentration increases with the increase of spindle speed and milling depth,and it is easier to spread to the distance;when the feed speed increases,the dust concentration decreases,and it is not easy to spread to the distance.When milling MDF in wood CNC machining center,the dust concentration distribution has certain directionality.Under this test condition,the dust concentration in machine tool-x direction is significantly higher than that in other directions.The distribution of dust concentration in different directions is quite different,the coefficient of variation is as high as 66.36%;when the spindle speed,feed speed and milling depth increase,the distribution of dust concentration in machine tool-x direction tends to be uniform.On the premise of meeting the processing requirements,measures such as reducing the rotation speed,reducing the milling depth and increasing the feed speed can be considered to reduce the dust concentration in the cutting plane,and at the same time,the dust removal equipment can be appropriately increased in the high concentration area.(3)In the study of the influence of cutting parameters on the dust concentration and dust reduction,the orthogonal experiment was used and the range analysis and variance analysis were used to analyze the data.The results show that the influence of cutting parameters on dust concentration,dust reduction and particle size distribution are different,Comprehensive consideration,the optimal parameters of this cutting: milling depth 1mm,feed speed 8m / min,spindle speed 10000 rpm.When distance is taken as a variable,the dust concentration near the dust source is the highest,and then decreases significantly first and then decreases slowly;the change rule of dust reduction is similar to that of dust concentration;the proportion of small particles increases with distance(4)In the aspect of establishing the mathematical model of dust concentration,according to the dust concentration value of the orthogonal test data,the multiple regression analysis of the dust concentration value is carried out,and the mathematical model of dust concentration is established and verified by the test.The results show that the model can accurately predict the dust concentration in MDF milling.The research results of this paper have a certain theoretical and application value.It can reduce the production of dust in the process of MDF milling from the source by changing the cutting parameters.