Tool Wear Effect on Surface Integrity in AISI 1045 Steel Dry Turning

In the present work, the surface integrity and flank wear of uncoated cermet inserts in dry turning of AISI 1045 steel were evaluated. Three-dimensional techniques were used to assess the surface roughness. Previously, finite element analysis was carried out to predict the cutting forces and heat distribution in the chip formation region. Cutting speed and feed were the parameters varied in the experiments. Feed is decisive in the final quality of the turned surface and cutting speed had little influence on this aspect. The surface was significantly damaged with the progression of the insert flank wear. Considering an average flank wear VBB of 0.1 mm, a tool life of 35 min was achieved using a cutting speed of 175 m/min, and of 23 min for a cutting speed of 275 m/min. Abrasive wear was predominant during the experiments. No microstructure defects were observed, as well as crack propagation or accentuated deformations near the machined surface region. Therefore, the dry turning of 1045 steel with cermet inserts route has proven extremely viable from the standpoints of tool life, surface integrity, chip formation, and sustainability.Thanks are also addressed to MICINN PDC2021-121792-I00. Special thanks to the basic collaboration scheme between the Brazilian groups and the Basque university group IT 573-22

Influência do contato entre ferramenta e peça no fresamento de superfícies curvas em aço H13 temperado e revenido

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2017.No contexto da fabricação de moldes e matrizes, a trajetória e direção de avanço da ferramenta definem os aspectos do contato entre a ferramenta e a peça influenciando o acabamento da superfície, a formação de cavacos, as acelerações e desacelerações dos eixos da máquina, desvios geométricos e, por conseguinte, o tempo de processamento. Neste trabalho, mapas tridimensionais são plotados utilizando-se a técnica da interferometria de luz branca para verificar a influência das trajetórias da ferramenta e do avanço por gume no fresamento, em três eixos, de superfícies hemisféricas de acentuado grau de curvatura, preenchendo assim lacunas existentes na literatura acerca do referido tema. É discutida a influência da direção de avanço no fresamento de um perfil cilíndrico, uma vez que não há consenso entre os pesquisadores sobre os impactos do contato do centro da ponta esférica da ferramenta no corte. Os experimentos são realizados na perspectiva do fresamento duro onde corpos de prova são processados em um único setup no aço H13 (55 HRC). Os resultados mostram que o tempo da etapa de acabamento pode ser reduzido em até 25%, em função da trajetória da ferramenta adotada. Verificou-se que a rugosidade da superfície curva é dependente significativamente da trajetória da ferramenta utilizada. Os desvios geométricos podem variar de 0,02 mm a 0,23 mm dependendo da trajetória da ferramenta. Em relação à textura da superfície os resultados mostraram que é sempre mais apropriado o emprego da direção ascendente, quando do fresamento de um perfil cilíndrico e que, neste caso, a rugosidade é prejudicada quando regiões próximas ao centro da ferramenta são atuantes no corte.Abstract : In the context of the manufacture of molds and dies the tool path and feed rate define the contact aspects between the tool and the part, influencing surface finish, chip formation, acceleration and deceleration of the machine axes, geometric deviations and, therefore, the processing time. In this work three-dimensional maps are plotted using the white light interferometry technique to verify the influence of the tool paths and the feed per tooth in the milling process, in three axes, of hemispherical surfaces with a significant curvature, thus filling the existing gaps in the literature on this topic. The influence of the direction of feed in milling a cylindrical profile is discussed, since there is no consensus among the researchers about the impacts of the contact of the center of the spherical tip of the tool in the cut. The experiments are performed from the perspective of hard milling where parts of H13 steel (55 HRC) are machined in a single setup. The results show that the time for finishing the part can be reduced by up to 25% provided that the chosen tool path is correct. It has been found that the roughness of the curve surface depends significantly on the tool path used. The geometric deviations may vary from 0.02 mm to 0.23 mm depending on the tool path adopted. With regard to the surface texture, the results showed that it is always more appropriate to use the upward direction when milling a cylindrical profile, and that in this case the roughness is worsened when regions near the center of the tool are acting in the cut

Assessment of the Chemical Reactivity of Brazilian Stone Cutting Plant Waste into Cementitious Matrices

The problems generated by the ornamental stone extraction and processing industry caused by the inadequate disposal of this waste can negatively affect rivers, lakes, streams, and even natural water reservoirs. This study discusses and evaluates the potentiality and challenges of dimension stone waste (DSW) recycling generated from a Brazilian dimension stone processing industry in Portland cement formulations. Cement pastes with different amounts of DSW (10–30 wt.%), quartz (10 wt.%), and calcium carbonate (10 wt.%) were prepared and characterized in the fresh and hardened states. The results showed that DSW can be used in cement formulations, and its reactivity is governed by the size of the particles. With up to 10% DSW in place of cement, the samples had greater workability and compressive strength at 28 days compared with the reference mix. However, the strength was lower at early ages (3 and 7 days). When DSW is milled, the strength of the samples containing the waste matched the reference values at all ages, and the recommended replacement limit rose to 20%. On the other hand, the particle size reduction significantly decreased the workability. The use of DSW in cement-based formulations is encouraged due to the strong presence of stone processing and cement companies in Brazil and worldwide

Assessment of the Chemical Reactivity of Brazilian Stone Cutting Plant Waste into Cementitious Matrices

The problems generated by the ornamental stone extraction and processing industry caused by the inadequate disposal of this waste can negatively affect rivers, lakes, streams, and even natural water reservoirs. This study discusses and evaluates the potentiality and challenges of dimension stone waste (DSW) recycling generated from a Brazilian dimension stone processing industry in Portland cement formulations. Cement pastes with different amounts of DSW (10–30 wt.%), quartz (10 wt.%), and calcium carbonate (10 wt.%) were prepared and characterized in the fresh and hardened states. The results showed that DSW can be used in cement formulations, and its reactivity is governed by the size of the particles. With up to 10% DSW in place of cement, the samples had greater workability and compressive strength at 28 days compared with the reference mix. However, the strength was lower at early ages (3 and 7 days). When DSW is milled, the strength of the samples containing the waste matched the reference values at all ages, and the recommended replacement limit rose to 20%. On the other hand, the particle size reduction significantly decreased the workability. The use of DSW in cement-based formulations is encouraged due to the strong presence of stone processing and cement companies in Brazil and worldwide