Carlos Henrique Lauro

Surface Roughness Investigation in the Hard Turning of Steel Using Ceramic Tools

The present work evaluates the use of conventional and multi-radii ceramic tools in the turning of AISI H13 in terms of surface quality. The selected design factors are the cutting speed, feed rate, and type of tool. To carry out this research, a design of experiments was used. The obtained results were analyzed using the analysis of variance (ANOVA), which allowed recognition of the influence of the feed rate and type of tool on the surface quality. By contrast, the cutting speed was found to be a factor that had no statistical significance. When comparing the experimental with the theoretical values, the results of the conventional and multi-radii tools were found to differ. In addition, it was highlighted that the feed rate has an important influence on the difference between the experimental and theoretical results.

Analysis of the Forces in Micromilling of Hardened AISI H13 Steel with Different Grain Sizes Using the Taguchi Methodology

The micromachining process has been applied to the free form and micromolds markets. This has occurred due to the growth in demand for microcomponents. However, micromachining of hardened steels is a challenge due to the reduction in tool life and the increase of the surface roughness when compared with the macromachining process. This paper focused on the analysis of micromilling forces on hardened AISI H13 steel with different grain sizes. Experimental tests were carried out on workpieces with different austenitic grain sizes and a hardness of 46 HRC. Micro-end-mill cutters with a diameter of 0.5 mm and (TiAl)N coatings were applied in the milling of workpieces of 11 × 11 mm. The input parameters were two radial depths of cut, two cutting speeds, and two feed rates. The influence of the input parameters on the response cutting force was analyzed using the Taguchi method. Finally, considering the large grain size, the cutting forces in the x-, y-, and z-axes direction were small.

Design of Experiments—Statistical and Artificial Intelligence Analysis for the Improvement of Machining Processes: A Review

The modern industry needs that its manufacture process to be fast, efficient, low cost, ecologic, and other. It occurs because many consumers require that the products have great quality and a fair price. Furthermore, in sometimes, the industry has the sale price imposes by client. Thus, the industry develops news techniques, process, tools, and other to attain this goal. However, these new developments require great studies to obtain the best condition and avoid that become more a waste. The Statistical or Artificial Intelligence (AI) Analysis are great ways to understand the new developments and obtain the best conditions. This review chapter presents the techniques (Statistical and AI) that were applied to plan and analyse the machining processes. Aim of this chapter is to argue the planning and analysis importance in researches, as well as help researchers to choose a technique and define their machining experiments, optimising the time, material and other means.

Finite Element Method in Machining Processes: A Review

An ecological production and low cost is the target of several industries. Increasingly, the product development is critical stage to obtain a great quality and fair price. This stage will define shapes and parameters that will able to reduce wastes and improve the product. However, the expense of prototypes also should be reduced, because, in general, the prototypes are more expensive that final product. The use of finite element method (FEM) can avoid much tests that reduce number of prototypes, and consequently the project cost. In the machining processes simulation, several cutting conditions can be reproduced to define the best tool and parameters in function of analyzed forces, stress, damages and others. This paper debates the use of FEM in the machining processes, shows some researches and indicates the main attributes to develop simulation studies for conventional machining and micromachining.

An Approach to Define the Heat Flow in Drilling with Different Cooling Systems Using Finite Element Analysis

The heat generated in the cutting zone with high-speed drilling causes damage in the machined part. The heat can affect the dimensions of the hole considering its diameter. Moreover, the heat reduces tool life of uncoated and coated tools. This paper shows experimental tests with high-speed drilling in hardened steel. Drilling was performed on AISI H13 steel with dimensions of 100 × 40 × 14 mm and 52 HRC. The work pieces were drilled with coated drills (TiAlN). A flooded lubricant system and the minimal quantity of lubricant (MQL) were applied to investigate the ability to remove heat from the cutting zone and to compare with dry tests. FEM was applied to define the heat flow and the coefficient of convection for the cooling systems. A steepest descent method was employed to minimize the difference between empirical and simulation data. The results showed that the simulation technique used to find values for heat flow and the coefficient of convection were close to the literature reference. In addition, the adjustment errors of the simulated temperature curves were less than 10% when compared with trial curves. Furthermore, the MQL showed a capability of cooling 3.5 times higher than that of the flooded system.

Influência da variação do tamanho de grão austenítico na qualidade superficial no processo de microfresamento do aço AISI H13 endurecido

The focus of this work was to study the influence of austenite grain size in the surface finish during micro milling of hardened steels. Work pieces with hardness of 46 HRC and different grain sizes were milled with micro end mills with a diameter of 0.5 mm. The experimental tests were carried out with two cutting speeds and two feed rates. The results were evaluated using an analysis of variance, and they demonstrated that the cutting speed and the feed rate have no influence on the responses surface roughness Ra and Rz. Thus, it could be observed that the most important factor was the grain size that influenced the roughness Ra and Rz, significantly. Moreover, it was also observed that the interaction of input parameters did not show significant influence on the response surface roughness Ra and Rz.

Analysis of Automotive Liftgate Seals Using Finite Element Analysis

Seals have wide application in automotive products. They are responsible for sealing the car in several parts such as the doors, the air intake cowl seal, and air intake lights seal. Strain and stress studies are very important in order to understand the behavior of polymeric materials, which are generally submitted to great workload variation and environmental influence. This study of EPDM rubber was carried out to define the strain, stress and yield stress. Tensile and compression tests were carried out on workpieces with 100 mm of length. The data were acquired using the Qmat software. A Finite Element Analysis using the MSC Marc Mentat™ was conducted and compared with experimental tests. The results showed an increase of effort proportional to bulb thickness. The proportional increase of compression effort for different displacements was significant. Moreover, physical parameters such as length, thickness, and friction coefficient changed the strain and stress rate.