Study of the plywood panels properties using geostatistic

Plywood panels have multiple applications in construction, in the furniture industry and packaging. There is a need to improve techniques for assessing quality of these products. This paper proposed the use of geostatistics to evaluate the behavior of the of the plywood panel. The physical properties were analyzed (moisture content, density and water absorption) in the full extent of the plywood panel of Eucalyptus sp., bonded with adhesive single-component polyurethane. For analysis, three panels of five layers, with dimensions of 350 x 350 x 15.5 mm each, were employed. The tests were based on the standards EN 323-2000, EN 322-2000 and ABNT NBR 9486- 2011. Statistical modeling was performed using the R software, using the methodology of geostatistics. The average results were compared with values reported in the literature. The average water absorption was 7% higher in comparison with other studies, which used urea formaldehyde. So, the product can be applied only to interior and their use is not advisable for floors; the average moisture content and density were within the average values found in the literature. The behavior of the properties analyzed using the geostatistical model was not homogeneous, with large variations. Geostatistics was considered an appropriate tool for the study of the variability of the plywood panel properties, and can be applied for better quality control of them.

Influência das técnicas de mínima quantidade de lubrificante, refrigeração otimizada e refrigeração convencional na qualidade de peças produzidas com aços endurecidos no processo de retificação

The influence of minimum lubrication, optimized and conventional cooling at different flows and application rates of cutting fluids on the quality of hardened-steel pieces produced by external cylindrical plunge grinding with super-abrasive grinding wheels with low CBN concentrations was verified. The analysis of the quality of the pieces was performed through the assessment of the behavior of the specific energy of the grinding, roughness, roundness deviation, and the generated residual stress. By analyzing of the application ways and of the several flows and application rates of the cutting fluid, one could encounter lubrication/cooling conditions that enable the reduction in cutting fluid volume, reduction in grinding time without compromising the dimensional parameters (superficial finishing, surface integrity). Regarding the different applications of cutting fluids, it could be noted the optimized application for higher velocities has presented the best performance, demonstrating the effectiveness of the new concept of nozzle utilized

GRINDING OF HARDENED STEELS USING OPTIMIZED COOLING RECTIFICADO DE ACEROS ENDURECIDOS USANDO REFRIGERACIÓN OPTIMIZADA

Grinding – the final machining process of a workpiece – requires large amounts of cutting fluids for the lubrication, cooling and removal of chips. These fluids are highly aggressive to the environment. With the technological advances of recent years, the worldwide trend is to produce increasingly sophisticated components with very strict geometric and dimensional tolerances, good surface finish, at low costs, and particularly without damaging the environment. The latter requirement can be achieved by recycling cutting fluids, which is a costly solution, or by drastically reducing the amount of cutting fluids employed in the grinding process. This alternative was investigated here by varying the plunge velocity in the plunge cylindrical grinding of ABNT D6 steel, rationalizing the application of two cutting fluids and using a superabrasive CBN (cubic boron nitride) grinding wheel with vitrified binder to evaluate the output parameters of tangential cutting force, acoustic emission, roughness, roundness, tool wear, residual stress and surface integrity, using scanning electron microscopy (SEM) to examine the test specimens. The performance of the cutting fluid, grinding wheel and plunge velocity were analyzed to identify the best machining conditions which allowed for a reduction of the cutting fluid volume, reducing the machining time without impairing the geometric and dimensional parameters, and the surface finish and integrity of the machined components.<br>La rectificación, proceso final de fabricación de una pieza, hace uso intenso de fluidos de corte con la finalidad de lubricación, refrigeración y remoción de astillas (imperfecciones). Sin embargo, estos fluidos son extremamente agresivos al medio. Con el avance tecnológico la tendencia mundial es producir piezas cada vez mas sofisticadas, con elevado grado de tolerancia geométrica, dimensional, con buen acabamiento superficial, con bajo costo y, principalmente, sin causar daños al medio. Para ello, al proceso de rectificación está intrínseco el reciclaje del fluido de corte, que se destaca por su costo. A través de la variación de la velocidad de avance en el proceso de rectificación cilíndrica externa del acero ABNT D6, racionalizando la aplicación de dos fluidos de corte y usando una muela superabrasiva de CBN (nitruro de boro cúbico) con ligante vitrificado, se evaluaron los parámetros de salida fuerza tangencial de corte, rugosidad, circularidad, desgaste de la herramienta, la tensión residual y la integridad superficial a través de la microscopia electrónica de barrido (SEM) de las piezas de prueba. Con el análisis del desempeño fluido, muela y velocidad de inmersión se encontró las mejores condiciones de fabricación propiciando la disminución del volumen de fluido de corte, disminución del tiempo de fabricación sin perjudicar los parámetros geométricos, dimensionales, el acabado superficial y la integridad superficial de los componentes

Grinding of hardened steels using optimized cooling

Grinding - the final machining process of a workpiece - requires large amounts of cutting fluids for the lubrication, cooling and removal of chips. These fluids are highly aggressive to the environment. With the technological advances of recent years, the worldwide trend is to produce increasingly sophisticated components with very strict geometric and dimensional tolerances, good surface finish, at low costs, and particularly without damaging the environment. The latter requirement can be achieved by recycling cutting fluids, which is a costly solution, or by drastically reducing the amount of cutting fluids employed in the grinding process. This alternative was investigated here by varying the plunge velocity in the plunge cylindrical grinding of ABNT D6 steel, rationalizing the application of two cutting fluids and using a superabrasive CBN (cubic boron nitride) grinding wheel with vitrified binder to evaluate the output parameters of tangential cutting force, acoustic emission, roughness, roundness, tool wear, residual stress and surface integrity, using scanning electron microscopy (SEM) to examine the test specimens. The performance of the cutting fluid, grinding wheel and plunge velocity were analyzed to identify the best machining conditions which allowed for a reduction of the cutting fluid volume, reducing the machining time without impairing the geometric and dimensional parameters, and the surface finish and integrity of the machined components

INFLUÊNCIA DAS TÉCNICAS DE MÍNIMA QUANTIDADE DE LUBRIFICANTE, REFRIGERAÇÃO OTIMIZADA E REFRIGERAÇÃO CONVENCIONAL NA QUALIDADE DE PEÇAS PRODUZIDAS COM AÇOS ENDURECIDOS NO PROCESSO DE RETIFICAÇÃO INFLUENCE OF THE METHODS FOR MINIMUM AMOUNT OF LUBRICATION, OPTIMIZED COOLING AND CONVENTIONAL COOLING IN THE QUALITY OF PARTS PRODUCED WITH HARDENED STEEL IN GRINDING PROCESSES

Verificou-se a influência das técnicas de mínima quantidade de lubrificante, refrigeração otimizada e refrigeração convencional, com diferentes vazões e velocidade de aplicação do fluido de corte, na qualidade das peças produzidas com aços endurecidos, no processo de retificação cilíndrica externa de mergulho com a utilização de rebolos superabrasivos com baixa concentração de CBN. A análise da qualidade das peças foi realizada através da avaliação do comportamento da energia específica de retificação, rugosidade, tensão residual gerada e desvio de circularidade. Com a análise das formas de aplicação e das várias vazões e velocidades do fluido de corte utilizadas encontraram-se condições de lubri-refrigeração que propiciam a diminuição do volume de fluido de corte, diminuição do tempo de usinagem sem prejudicar os parâmetros dimensionais, o acabamento superficial e a integridade superficial. Em relação às diferentes formas de aplicação do fluido de corte notou-se o melhor desempenho da aplicação otimizada para maiores velocidades mostrando a eficiência de um novo conceito de bocal utilizado.<br>The influence of minimum lubrication, optimized and conventional cooling at different flows and application rates of cutting fluids on the quality of hardened-steel pieces produced by external cylindrical plunge grinding with super-abrasive grinding wheels with low CBN concentrations was verified. The analysis of the quality of the pieces was performed through the assessment of the behavior of the specific energy of the grinding, roughness, roundness deviation, and the generated residual stress. By analyzing the application ways and of the several flows and application rates of the cutting fluid, lubrication/cooling conditions that enable the reduction in cutting fluid volume, reduction in grinding time without compromising the dimensional parameters (superficial finishing, surface integrity) could be found. Regarding the different applications of cutting fluids, the optimized application for higher velocities showed the best performance, thus showing the effectiveness of the new concept of nozzle used

Influence of optimized lubrication-cooling and minimum quantity lubrication on the cutting forces, on the geometric quality of the surfaces and on the micro-structural integrity of hardened steel parts

The is paper presents an analysis of the influence of minimum quantity lubrication (MQL), optimized and conventional cooling, using different cutting fluid volumes and flow rates, on the surface quality and integrity of hardened steel workpieces, in cylindrical plunge grinding with superabrasive CBN grinding wheels. The final quality of the workpieces were evaluated based on an assessment of output variables such as the behavior of: tangential cutting force, specific energy, surface roughness, roundness errors, acoustic emission, residual stresses, scanning electron microscopy (SEM) micrographs, and microhardness. The present analysis of the various forms of cutting fluid application identified cooling conditions which favor the minimization of cutting fluid usage, and shorter machining times without impairing the geometrical and dimensional parameters, surface finish and surface integrity of the workpieces. Among the various forms of cutting fluid application, optimized lubrication at higher outlet speeds showed the best performance, confirming the efficiency of the new nozzle concept employed in this study. The optimized and MQL processes were successful in maintaining the hardness and surface integrity of the ground workpieces. The only exception was the use of MQL with a flow rate of 40ml/h, which caused cracking and quenching of the workpiece surface. The lowest surface roughness values obtained with MQL were obtained using higher flow rates of lubricant. The surface roughness values obtained with MQL are high for the grinding process. Low-concentration CBN wheels, which are less expensive and subject to less wear, produce good results when associated with more efficient cutting fluid application techniques.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Influence of grinding on the roundness, residual stresses and microstructure of VC131 steel analysed by varying the type of cutting fluid

This paper by R. E. Catai, E. C. Bianchi, P. R de Águia and M. C. Alves reports on the results of an analysis made of roundness errors, residual stresses, and SEM micrographs of VC131 steel. The analysis involved workpieces ground with two types of cutting fluid: synthetic cutting fluid and emulsive oil. In this study, the cutting parameters were kept constant while the type of cutting fluid was varied. The amount of cutting fluid injected in the process was also varied, aiming to identify the ideal amount required to obtain good results without causing structural damage to the workpiece. The SEM analyses of roundness errors and residual stresses revealed that, of the two cutting fluids, emulsive oil provided better tensions due to its greater lubricating power

Effects of belt speed, pressure and grit size on the sanding of pinus elliottii wood

The present paper aims to evaluate the influence of the factors (belt speed, pressure and grit size) on the output parameters (temperature and surface roughness) for Pinus elliottii wood sanding, processed parallel to the fibers. Three levels of belt speed, three levels of pressure and four levels of grit size were employed, with six replicates for each process, totaling 216 observations. The experiment conducted under a randomized complete block design (RCBD). The results were analyzed employing the analysis of variance (ANOVA) with 5% of significance level. Only grit sizes were significant to different temperature levels. The same outcome was observed for roughness, where only grits sizes were significant. No interaction between the pressure and belt speed factors were observed for all the results analyzed.Neste trabalho, objetivou-se observar o efeito dos fatores de entrada (velocidade, pressão e granulometrias de lixa) sobre as variáveis de saída (temperatura e rugosidade) no processo de lixamento plano do Pinus elliottii, processados paralelo às fibras. Foram utilizadas três velocidades, três pressões, quatro granulometrias de lixa com seis repetições para cada combinação, totalizando 216 tratamentos. O experimento foi planejado para um delineamento em blocos completamente aleatorizados (DBC). Os resultados foram analisados por meio de uma análise de variância (ANOVA) com nível de significância de 5%. Para a temperatura, observou-se que somente a granulometria de lixa teve uma influência significativa no aquecimento do sistema. Da mesma forma, a apenas a granulometria de lixa influenciou significativamente na rugosidade. Não foi observada interação entre os fatores pressão e velocidade para todos os resultados analisados.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP