Papers by Keyword: Machining

Abstract: Virtual manufacturing is a field of research which numerically simulate all the manufacturing processes seen by a mechanical part during its production (for example casting, forging, machining, heat treatment,…). Its use is rising on various industries to reduce production costs and improve quality of manufactured parts. One of the most challenging component of the whole simulation chain is the simulation of machining operations due to some of its specificities (need of material law at high strain, strain rates and temperature, heterogeneities of machined material, influence of residual stresses,…).In order to circumvent these difficulties, macroscopic models of machining process have been developed in order to compute more global information (cutting forces, stability of the process, tolerance or roughness for example). For this approach, the cutting forces computation is done by using simple analytical law based on mechanistic approach. The parameters of the models have no clear physical meaning (or at least cannot be linked to intrinsic properties of the material to be machined) and are therefore considered constants for a given set of simulations.The aim of this paper is to take into account the uncertainty on the variability of the cutting force signal during machining operation used as input for mechanistic model identification. The variability of the response during a test on fixed conditions (cutting tool, machined material and cutting parameters) is taken into account to develop a model where parameters of the model can evolve during a given operation.The proposed model is then used as an input of a milling operation simulation in order to study its influence on machining stability as compared to a classical approach.

Abstract: This paper presents the results of experimental research of the authors in terms of overall vibration behavior MUSD (machine tool, tool-device) during processing by removing metal on a pump body on a CNC milling and boring machine. At the research conducted in this direction were considered mechanical vibration measurements occurred during the processing of various operations of the technological process in parallel with noise measurements. These experimental research in determining the direction of vibration occurring in machining process led to some conclusions about the interdependence between the intensity and quality cutting data processing carried out and the influence of noise pollution produced.

Abstract: The main rejections in the machining sections are exhaust valve port leak, injector bore blow hole, induction passage punchered, inlet valve port leak, top face unwash, valve guide hole blow hole, top face leak, joint face unwash, induction face unwash, rear face unwash, valve port unwash, water mixing with oil., water passage blocked, emf leak, injector bore leak, inlet valve port blocked, water way leak, oil way leak and defective jig location pad. This paper describes the method by which the rejections while maching the cylinder head, is minimized.

Abstract: Titanium alloys are attractive materials used in different engineering applications, due to its excellent combination of properties such as high strength to weight ratio, good corrosion resistance and high temperature applicability. They are also being used increasingly in chemical process, automotive, biomedical and nuclear plant. When machining of Titanium alloys with traditional tools the tool wear rate high. Because of high chemical reactivity and low modulus of elasticity resulting high cutting temperature and strong adhesion between the tool and work piece materials. The poly crystalline diamond (PCD) cutting tool is used for the turning experiment. The turning parameters for the experimental work are cutting speed, feed, nose radius, and depth of cut. From the results, analysis of the influences of the individual parameters on the surface roughness have been carried out. Fuzzy modeling technique is effectively used to predict the surface roughness in the machining of titanium alloy.

Abstract: Cellulose based hybrid composites are gaining popularity in the growing green communities. With extensive studies and increasing applications for future advancement, the need for an accurate and reliable guidance in machining this type of composites has increased enormously. Smooth and defect free machined surface are always the ultimate objectives. The present work deals with the study of machining parameters (i.e. spindle speed, feed rate and depth of cut) and their effects on machining performance (i.e. surface roughness and delamination) to establish an optimized setup of machining parameters in achieving multi objective machining performance. Cellulose based hybrid composites consist of jute (a bast fiber) and glass fiber embedded in polyester resins. Response Surface Methodology (RSM) using Box-Behnken Design (BBD) was chosen as the design of experiment approach for this study. Based on that experimental approach, 17 experimental runs were conducted. Mathematical model for each response was developed based on the experimental data. Adequacy of the models were analyzed statistically using Analysis of Variance (ANOVA) in determining the significant input variables and possible interactions. The multi objective optimization was performed through numerical optimization, and the predicted results were validated. The agreement between the experimental and selected solution was found to be strong, between 95% to 96%, thus validating the solution as the optimal machining condition. The findings suggest that feed rate was the main factor affecting surface roughness and delamination .

Abstract: This article deals with special kind of machining of multi-layer laminar composites called sandwich composites. This material consists of two outer layers that overlap core material at the centre made from a light material. This material is used in the automotive industry in interior parts such as dashboards, decorative parts and panels. The product is folded from thin plastic and aluminum. As customers require high-end quality for higher class-vehicles, machining must be ensured at as high a level as possible to suit customer demands. Appropriate processing methods have been investigated experimentally in order to choose the best tool that would guarantee a consistently high quality of cut depending on high durability. Therefore it is still necessary to permanently test new tools with different types of coating, including thin films and different geometry to achieve the required quality at less clamping milling tools, which need to be changed after some pieces and edge sharpen.

Abstract: Machining can be performed on virtually all solid materials even though the term commonly applies to the cutting of metals, alloys, plastics and woods. Machining is a mechanical process where excess material from a work piece can be removed by cutting action to produce a part of specified geometrical shape and surface finish. In this research we will analyze and investigate whether there is a possibility to use the palm oil based bio wax material for machining applications. At the moment different ferrous, non-ferrous materials and industrial blue wax have been used for prototype models, training purpose by different industries, educational and training organizations. However the price of such material is very expensive. Hence an attempt is made to substitute these material by the palm oil based bio wax produced in Malaysia. With it, engineers can generate prototype to evaluate even minor design changes without breaking the budget. To the best of researcher’s knowledge, no previous work has been carried out nationally or worldwide on the use of palm oil based bio wax material in the manufacture of a strong industrial wax. This research work gives the approaches taken in this direction.

Abstract: This study analyzed the bond line strength of Eucalyptus sp. specimens submitted to shear and perpendicular to grain tensile forces, depending on the wood quality machined surface. The woods plans were glued with two different polyvinyl acetate adhesives. The bonding surfaces were milling with three different feed speeds; 6.0, 11.0 and 15.0 m/min, corresponding to the feed per tooth of the cutting tool; 0.86, 1.57 and 2.14 mm, respectively. The specimen types corresponded to the standards according to ABNT NBR 7190/1997. The cutting plane considered only the geometry of milling due to the bond line joint strength. To explain the experimental results, was proposed a linear elastic model to machined wood and bond line. For the two adhesives used, the experimental results suggest that the greatest perpendicular to grain tensile strength and shear strength were obtained to bond surface machined with the intermediate feed speed namely 11 m/min, for others two feed speeds and in the shear strength case, was not observed a distinction between them, in the perpendicular to grain tensile strength, the feed speed 6.0 m/min presented a higher strength than the machined surface with 15.0 m/min. The model reproduces the behavior of the experimentally results obtained for the two tests, and so it can be readily applied as a tool for evaluate the machining feed speed and the bond line joint strength.

Abstract: The selection of an adequate friction model is an important aspect inthe finite element modeling of machining. Previously, different friction modelshave been compared, but the influence of the constitutive model or theworkpiece material have not been considered. This article focuses on theinfluence of the material and the constitutive model on the evaluation of thefriction model in machining. Numerical experiments are performed on threedifferent materials using different constitutive models. For every combinationof material and constitutive model, several simulations using different Coulombcoefficients, but the same cutting parameters, are performed. Several variablesare evaluated: cutting force, shear plane angle, chip-tool contact length,maximum temperature and maximum stress. The results reveal that the workpiecematerial plays an important role in the evaluation of the friction model. Theyalso show that there is significant influence from the constitutive models oncontact length, curvature ratio and chip thickness.

Abstract: For rotational parts with irregular curve profile, in order to achieve its manual programming and machining, we need to segment the contour curve according to the change of curvature. Through the calculation, we can get the minimum arc to fit the segments, and calculate the circular endpoint coordinates and radius by using the drawing methods. Finally, we develop the NC program. By the analysis of the result, we find the method can simplify the programming and improve machining efficiency.