Explore the vast range of titles available.

Wood dust produced in medium-density fiberboard (MDF) processing is a major occupational hazard in wood industry and may damage processing equipment. In many wood processing factories, dust collecting systems need to be optimized for the distributional and morphological characteristics of dust in the workshop so that economical and efficient dust control can be achieved. In this study, weighting, image analysis and scanning electron microscopy (SEM) were applied to explore the effects of different cutting speeds on the distribution and morphology of dust generated in MDF milling. The results showed that most dust particles were less than 100 μm and that the aspect ratios (AR) were between 0.6 and 0.7. There was significant difference in particle number size distribution (PNSD) between the dust at different sampling positions. Less amount of dust was located close to cutting center, and fine dust was more likely to appear far away from cutting center. Cutting speed was associated with PNSD, but had little effect on AR. The findings provide spatial distribution characteristics of MDF dust during milling, which can be helpful for optimizing cutting parameters and locating dust collecting hoods to minimize dust exposure.

Manufacturing processes, such as machining, transform raw materials into finished goods, and these processes consume significant energy. There is an increasing concern about the energy required for such processes and the environmental consequences attributable to the generation of the energy. Reducing the energy required to perform machining operations will not only reduce the environmental footprint, but also provide economic benefits. To that end, the effects of cutting conditions (e.g., feed and speed) and tool geometry (diameter and number of teeth) on the power required for an end milling operation are investigated experimentally. Experimental results are presented from a cutting mechanism perspective with the goal of understanding the role of the process variables. The specific cutting energy (SCE) is found decreasing when material removal rate increases, but there is substantial variation about the general trend. In essence, the cutting parameters and the tool geometry influenced the changes of average chip thickness and cutting speed, which cause the shear deformation energy changes and eventually collectively influence the SCE’s change. Based on the experiments, suggestions on selecting process parameters are provided to improve milling energy efficiency.

The massive amounts of dust formed during bamboo CNC milling presents serious risks to human health and equipment. The present study aimed to determine the particle size distribution (PSD) and shape characteristics of bamboo milling dust derived from different average chip thicknesses. Spindle speed and feed rate were varied in combination, in setting up two experimental groups having the same average chip thicknesses. Sieving and flatbed scanning image analyses were collectively utilized for the morphological analysis of bamboo dust. The results showed that less than 5% of the particles were below 100 μm in terms of mass, but represented more than 83% in number. Average chip thickness was positively correlated with a mass proportion of bamboo dust with large size, which was preferably generated when reducing spindle speed instead of increasing feed rate. Spindle speed and feed rate individually affected the particle size and particle size distribution instead of average chip thickness. The aspect ratio, roundness and convexity of bamboo milling dust were augmented with a reduction in particle size, indicating that bamboo milling dust with smaller size had more a regular shape, a smoother profile and fewer corners. These findings provide a theoretical basis for better understanding bamboo milling dust and its related control in the bamboo processing industry.

Abstract Structured grinding wheel has obvious advantages in reducing grinding force, and the structural parameters of grinding wheel have important influence on the reduction of grinding force. In order to determine the influence law of structural parameters on grinding force, the following theoretical modeling and experimental research work are carried out in this paper. Firstly, single grit scratching experiments of the workpiece material are carried out to determine the critical cutting depth for ploughing and cutting transition. The influences of structural parameters on the maximum undeformed chip thickness and the average contact arc length during grinding are analyzed in detail. The abrasive grains are simplified into a cone with an apex angle of 120°, the surface topography model of the structured grinding wheel is established according to the measured results of the distribution law of abrasive grains on the surface of the grinding wheel and the structural characteristic parameters. Combined with the grinding force model of single abrasive grain in ploughing and cutting stages, the grinding force calculation model of straight groove structured grinding wheel is established during the grinding process. Finally, grinding experiments are carried out to verify the accuracy of the theoretical grinding force model. The results show that the calculated values of grinding force are in good agreement with the experimental values, and the maximum calculation errors of tangential grinding force and normal grinding force are 14.5% and 11.8%, respectively. It is found that when the intermittent ratio of structured grinding wheel is constant, the groove width has little influence on grinding force. However, when the groove width is constant, the intermittent ratio has a great influence on the grinding force, and with the increase of the intermittent ratio, the grinding force decreases obviously.

It is agreed upon that labor’s health conditions, as well as environmental pollutions, are broadly influenced by cutting fluids used in machining operations. In order to secure cleaner work parts and environment as well as reduced machining expenses, less fuel consumption is highly recommended. However, the quality of machined parts in the absence of fluid is considered a delicate subject. Under such conditions, the quality of machining process, as well as productivity, could be evaluated by different parameters and criteria including edge and surface quality, chip thickness, cutting force, and tool wear and life, which all seem to be highly influenced by many factors, including lubrication mode (dry and wet) and chip evacuation process. In order to take the benefits while avoiding the disadvantages of lubricated machining, novel lubrication method the so-called minimum quantity lubrication (MQL), which is micro lubrication near dry machining, is proposed. Review of literature denotes that under MQL condition, a low volume of information is available on the effects of mineral and bio-lubricants and various levels of flow rate on machining attributes, in principle average surface roughness ( R a ) and chip thickness ( h c ) when machining aluminum alloys (AAs). To remedy the lack of knowledge determined, the effects of cutting conditions, in principle cutting speed, feed rate, lubricant, and various levels of flow rate on R a and h c in MQL turning of AA 6061-T6 and AA 7076-T6, are presented. Therefore, three different experimental models, including multiplicative, 2-factor interactions (2FI), and linear models, were used in this study to assess the effects of cutting parameters on the machining outputs. According to experimental observations and despite the design models used, both R a and h c are statistically significant responses and could be controlled by variation of the cutting parameters used. A strong relationship can be formulated between both responses and experimental parameters used. Although negligible, however, biodegradable cutting fluid with higher viscosity denoted better capability to improve the surface finish. The use of a higher flow rate also led to improved surface finish (up to 50%). It was observed that despite the material used, both flow rate and cutting fluid have insignificant effects on h c .