Ali Davoudinejad

3D Finite Element Simulation of Micro End-Milling by Considering the Effect of Tool Run-Out

Understanding the micro milling phenomena involved in the process is critical and difficult through physical experiments. This study presents a 3D finite element modeling (3D FEM) approach for the micro end-milling process on Al6082-T6. The proposed model employs a Lagrangian explicit finite element formulation to perform coupled thermo-mechanical transient analyses. FE simulations were performed at different cutting conditions to obtain realistic numerical predictions of chip formation, temperature distribution, and cutting forces by considering the effect of tool run-out in the model. The radial run-out is a significant issue in micro milling processes and influences the cutting stability due to chip load and force variations. The Johnson–Cook (JC) material constitutive model was applied and its constants were determined by an inverse method based on the experimental cutting forces acquired during the micro end-milling tests. The FE model prediction capability was validated by comparing the numerical model results with experimental tests. The maximum tool temperature was predicted in a different angular position of the cutter which is difficult or impossible to obtain in experiments. The predicted results of the model, involving the run-out influence, showed a good correlation with experimental chip formation and the signal shape of cutting forces.

Effects of Cutting Condition on Surface Roughness when Turning Untreated and Sb-Treated Al-11%Si Alloys Using PVD Coated Tools

Surface roughness is an important output in different manufacturing processes. Its characteristic affects directly the performance of mechanical components and the fabrication cost. In this current work, an experimental investigation was conducted to determine the effects of various cutting speeds and feed rates on surface roughness in turning the untreated and Sb-treated Al-11%Si alloys. Experimental trials carried out using PVD TIN coated inserts. Experiments accomplished under oblique dry cutting when three different cutting speeds have been used at 70, 130 and 250 m/min with feed rates of 0.05, 0.1 and 0.15 mm/rev, whereas depth of cut kept constant at 0.05 mm. The results showed that Sb-treated Al-11%Si alloys have poor surface roughness in comparison to untreated Al-11%Si alloy. The surface roughness values reduce with cutting speed increment from 70 m/min to 250 m/min. Also, the surface finish deteriorated with increase in feed rate from 0.5 mm/rev to 0.15 mm/rev.

Investigation into Effect of Tool Wear on Drilling Force and Surface Finish While Dry Drilling Aluminum 2024

Dry drilling of aluminum is environmentally friendly machining technique; in the meanwhile it is difficult to carry out due to aluminums gummy behavior and its tendency to adhere to cutting tools which diminishes hole quality. In spite of recent developments in cutting tool technology, HSS tools are still a cost effective choice due to relatively high toughness and feasibility to manufacture complex geometries of HSS drills besides its low price, make this tool a common choice for drilling soft materials such as aluminum. In this study effect of tool wear on thrust force and torque analyzed and hole quality assessed with respect to tool wear along tool life. Dry drilling on aluminum 2024, performed using HSS and HSCo drills at constant feed rate of 0.04 mm/rev and two cutting speeds of 28 and 94 m/min. Results revealed that the abrasive wear on flank face and BUE on chisel edge, margin and cutting lips were dominant mechanisms in all drills. It was found that with propagating the wear land on tool, thrust force and torque increased in both tools.

Experimental Analysis of Wear Mechanism and Tool Life in Dry Drilling of Al2024

Aluminum alloy is widely used in industry and various researches has been done on machiability of this material mainly due to its low weight and other superior properties. Dry machining is still interesting topic to reduce the cost of manufacturing and environmental contaminations. In present study dry machining of Al 2024 investigated on tool life, tool wear mechanisms, hole quality, thrust force and torque. Different types of high speed steel (HSS) tools utilized at constant feed rate of 0.04 mm/rev and cutting speeds within the range of 28 and 94 m/min. Experimental results revealed that HSCo drills, performed better than HSS drills in terms of tool life and hole quality. The main wear mechanisms which analyzed by scanning electron microscope found abrasive and adhesion wear on flank face, besides, BUE observed at chisel and cutting edges. However tool wear and BUE formation found more significant at high cutting speed. In terms of thrust force, two facet HSCo tools, recorded higher thrust force than four facet HSS drills.

Effect of Tool Wear on Tri-Phase CVD Coated Carbide Tools Life while Turning Al6061

Aluminum 6061 is a common alloy which is widely used in aerospace and yacht construction industry. Generally machining of aluminum alloys inherently generates high chip sticking on tool face and changes the tool edge geometry, which not only reduces tool life but also impairs the product surface quality. This study investigated the tool life and tool wear mechanisms besides evaluating surface roughness in various cutting conditions to attain finest possible surface with minimum tool wear. Turning experiments performed under dry orthogonal cutting of Al6061 using carbide CVD tri-phase coated inserts with constant depth of cut, various cutting speeds and feed rates. Insert’s flank and rake faces analyzed to assess wear mechanisms. Additionally Scanning electron microscope (SEM) employed to clarify different types of wear. Surface integrity and effect of built up edge in deviating surface roughness were studied in each cutting condition. Additionally results of experiments demonstrated that built up edge took over cutting edge and with sacrificing surface roughness, tool life increased by decreasing pace of abrasive wear propagation on flank face. According to these experiments the main reasons of flank wear were abrasive and adhesion of aluminum on tool face.

Assessment of hole quality and thrust force when drilling CFRP/Al stack using carbide tools

Drilling composite materials is challenging due to the anisotropic and non-homogenous structure of composites. In fabrication works, metals are joined to composites to form a hybrid strengthened structures, and this posed a great problem during drilling, due to the dissimilar drilling conditions for each material and also sharp metal chips effect on the quality of hole on composite plates. This paper evaluates the experimental results on the machining performance of coated and uncoated 4 facet carbide drills when dry drilling stack of carbon fiber reinforced plastic (CFRP) and aluminum. Drilling trials were carried out on CFRP/Al2024/CFRP stack at constant cutting speed of 37 m/min with three feed rates within 0.03-0.25 mm/rev. Results revealed that 4 facet coated drills performed better than uncoated drills in terms of delamination. It was found that hole entry delamination increases with increasing feed rate, however uncut fibers which were dominant at low feeds on hole exit, disappears with increasing feed rate. It was also found that thrust force for coated tools were quite higher than uncoated tools.

Investigation into Different Tool Coating performance While Turning Al6061

Cutting tool material technology in recent years has made great strides with substantial improvements in their strength, toughness, and wears resistance, which are designed to increase productivity, improve tool selection and aid to decrease costs and promote machining quality. This investigation presents the effect of various cutting speeds in turning of Al6061 with respect to different coatings. Experiments carried out under orthogonal dry cutting, and two different cutting speeds applied which were 250, 500 m/min. Feed rate and depth of cut kept constant respectively at 0.05 mm/rev and 0.5 mm in experiments. Three different carbide cutting tools have been used namely CVD tri-phase multilayer TiC/TiCN/TiN coated, PVD TiN coated and CVD TiC/Al2O3 coated. Tool performance was determined with respect to tool wear and surface finish in tests. Results obtained that tri-phase coated illustrated longest tool life, however best surface finish achieved by TiN coated tool. In addition adhered material which mainly formed in CVD tri-phase TiC/TiCN/TiN and TiC/Al2O3 coated tools, at higher cutting speed deteriorated surface finish in comparison to lower cutting speed.

Effect of Tool Wear on Tool Life and Surface Finish when Machining DF-3 Hardened Tool Steel

Hard turning is a dominant machining operation performed on hardened materials using single-point cutting tools. In recent years, hard turning operation has become more and more capable with respect to various machinability criteria. This work deals with machinability of hardened DF-3 tool steel with 55 ±1 HRC hardness at various cutting conditions in terms of tool life, tool wear mechanism and surface roughness. Continuous dry turning tests were carried out using coated, mixed ceramic insert with honed edge geometry. Two different cutting speeds, 100 and 210 m/min, and feed rate values of 0.05, 0.125 and 0.2 mm/rev were used with a 0.2 mm constant depth of cut for all tests. Additionally scanning electron microscope (SEM) was employed to clarify the different types of wear. As far as tool life was concerned, best result was achieved at lowest cutting condition whereas surface roughness values decreased when operating at higher cutting speed and lower feed rate. Additionally maximum volume of material removed is obtained at low cutting speed and high feed rate. Dominant wear mechanism observed during the experiments were flank and crater wear which is mainly caused by abrasive action of the hard workpiece material with the ceramic cutting tools.

Effect of Tool Edge Geometry on Cutting Force and Surface Roughness when Hard Turning Tool Steel

High usage of hardened steel in the automotive, gear, bearing, tool and die making industries, makes it a highly suitable material for industrial production and research. This study was undertaken to investigate the performance of coated ceramic insert with different edge preparations in terms of cutting force and surface roughness. Plain turning experiments were carried out under dry cutting condition at two different cutting speeds and feed rates with a constant depth of cut. The workpiece material is ASSAB DF-3 hardened steel with a 55 ±1 HRC hardness. Results showed that insert edge preparation had a direct influence on the radial and feed forces but not on the tangential force. The use of T-land edge preparation results in the lowest radial and feed forces. In terms of surface finish, the use of honed with finishing wiper insert results in obtaining the lowest surface roughness values. Feed rate had a significant effect on surface roughness whereby by increasing feed rate, the surface roughness value also increased, whereas the effect of cutting speed was found to be insignificant. Increasing cutting speed resulted in lower feed and tangential forces however by increasing feed rate all cutting forces increased.

Investigations into Effect of Tool Wear on Surface Integrity in Dry Turning of Al6061

Aluminum alloys offer number of various interesting mechanical and thermal properties which classified them among most commonly used lightweight metallic materials. Generally machining of aluminum alloys inherently generates high chip sticking on tool face and changes the tool edge geometry, which not only reduces tool life but also impairs the product surface quality. This study investigated tool wear mechanism, surface integrity, and tool life in different cutting conditions to achieve finest surface roughness with considering longest tool life. Turning experiments performed under dry orthogonal cutting of Al6061 using carbide CVD tri-phase coated inserts. Constant depth of cut with different cutting speeds and feed rates utilized in experiments. Insert’s rake and flank faces investigated to figure out wear mechanisms. In addition scanning electron microscope (SEM) employed to evaluate various wear types. Surface integrity and effect of built up edge in surface roughness deviations studied in each cutting condition. Additionally, results of experiments demonstrated that built up edge covered tool cutting edge and increased tool life by decreasing pace of the abrasive wear propagation on the flank face with sacrificing surface roughness. All in all the main reason for flank wear was abrasive and adhesion of aluminum on tool faces.