Study On Dust Characteristics And Cutting Parameter Influence In Particleboard Milling Process

There are three major sources of environmental pollution in wood processing industry: dust,sewage and noise,among which wood dust pollution has the greatest impact.Wood dust monomer is small in weight and complex in shape.Fine dust particles are easy to spread and explode in the air,which will not only cause occupational diseases,but also cause potential safety hazards.The generation of dust is inevitable during the wood processing.The control and treatment of wood dust has always been a thorny problem in wood processing industry.As an important part of wood processing industry chain,Wood-based panel is widely used in furniture,cabinet,wooden door and other industries.Among them,particleboard plays an important role in the production and application of wood-based panel because of its smooth surface and good processing performance.However,the secondary processing of wood-based panels,such as milling,has some problems,such as high dust concentration and unsatisfactory dust removal effect.People have a vague understanding of the characteristics of wood dust in wood-based panel processing,such as particle shape and size characteristics,dust concentration distribution,powder fluidity,etc.,which not only hinders the improvement of dust removal efficiency in processing area,but also brings security risks to the safe and stable operation of equipment in the processing workshop.In this paper,the distribution characteristics of wood dust in the milling process of threelayer structure particleboard were studied,and the effects of cutting parameters on dust morphology,particle fluidity,dust concentration,surface quality and concentration variation coefficient were analyzed.The conclusions are as follows:(1)Particle size and concentration distribution characteristics of particleboard milling dust.The influence of the average cutting thickness on the particle size distribution of the surface and core shavings was analyzed through the variable experiment of the average cutting thickness.Meanwhile,the distribution characteristics of the dust concentration of the surface and core shavings were studied under the fixed cutting parameters.The results show that most of the milling dust of particleboard is fine particles within 20-30 ?m.Due to the difference of surface morphology and interlayer adhesion between surface and core shavings,,with the increase of average cutting thickness,the proportion of milling fine dust in surface shavings decreases,while the particle size distribution of milling dust in core shavings is irregular,and the average particle size and median particle size of surface shavings are smaller than that of core shavings.The high concentration area of particle milling dust is located in the center of the dust source,and the diffusion direction and degree of suspended dust particles are different between the surface layer and the core layer.Besides,due to the difference of cutting mechanism,the concentration of milling dust in the surface layer is higher than that in the center of dust source,and the reduction rate of milling dust concentration in the core layer is faster with the increase of distance.(2)Influence of cutting parameters on particle shape and fluidity of dust.The image method was used to analyze the change of the length width ratio and firmness of particle shape parameters of particleboard milling dust when a single cutting parameter was changed,and the fluidity of milling dust was measured by injection method.The results show that the length width ratio of particle milling dust is low,and the particle is irregular in macro morphology,as well as the morphology of particle milling dust varies greatly among individuals.The average firmness of dust particles is high,which indicates that the surface texture is relatively flat.Generally,particleboard milling dust belongs to the dust with poor fluidity.With the decrease of particle size,the fluidity of dust further decreases.Reducing the spindle speed,increasing the feed speed and milling depth can improve the fluidity of large particle chips,which is conducive to the collection and transportation of dust in the pneumatic conveying dust removal system.(3)The optimization of cutting parameters in particleboard milling.The influence of cutting parameters and milling cutter type on the dust concentration and surface roughness of workpiece at fixed sampling point was analyzed by orthogonal test.The results show that the dust concentration and surface quality of particleboard milling with different cutters are different.Generally,low feed speed and small milling depth can obtain relatively low dust concentration and relatively good machining surface quality.The selection of spindle speed value needs to be comprehensively considered according to different machining materials and tools.(4)Prediction model of dust concentration in the milling plane of particleboard.Through the multiple linear regression analysis of the average dust concentration in four directions on the XOY milling plane measured by orthogonal experiment,the mathematical model of dust concentration is established and its reliability is verified.The results show that the model can accurately predict the dust concentration in all directions of the milling plane of particleboard under different cutting parameters,so that can be used to evaluate the distribution and diffusion of suspended dust particles.This study provides a theoretical basis for the effective control of processing conditions and the reduction of wood dust pollution in particleboard milling process.