AISI 316 L stainless steel is one of the difficult material to machine by traditional machining process due to its low thermal conductivity and high ductility properties which can cause high tool ...wear and high cutting forces. This can be addressed while using cutting fluid, however, cutting fluid causes severe environmental pollution while disposal. In recent studies, the usage of surface textures on cutting tools exhibited an improved machining performance without cutting fluids. The present work made an attempt to fabricate positive (protruded) surface textures on HSS cutting tool rake face and study its effect on the machining performance of AISI 316L stainless steel under dry machining. The surface textures are fabricated using the reverse-electro discharge machining process. In the present work, the effect of texture parameters such as texture density, texture height and diameter on the machining performance parameters like cutting forces, flank wear and machined surface quality of the machined workpiece are studied. The results indicated that a positive (protruded) surface textured cutting tool exhibits better machining performance as compared to the un-textured cutting tool. In addition, among the texture parameters, texture height has a significant effect on machining performance. Moreover, textured tool with a combination of 150 µm texture diameter, 5% texture density and 300 µm texture height shown better machining performance. It has also been observed that tool life is improved up to 110% as compared to un-textured tool.
Ti-6Al-4 V alloy is the most widely used titanium alloy due to its non-corrosive nature, excellent strength to weight ratio and strength retention at relatively high temperatures. However, poor ...machinability of this alloy, for acquiring desired shapes and finishing levels, is a challenge which needs to be addressed. This is due to high hardness and chemical reactivity with the cutting tool at elevated temperatures. Thus, there is a need to develop certain effective measures for overcoming these limitations in Ti-6Al-4 V machining. These include optimization of input machining parameters and use of advanced cutting tools, machine tools as well as heat dissipation techniques from the cutting zone. The optimization of input parameters during machining requires precise measurement and analysis of various output parameters viz. tool wear, surface roughness, cutting forces, cutting temperatures, tool vibration etc. Of these, cutting forces and cutting temperature are difficult to measure experimentally, thus often various theoretical modelling techniques are employed to determine these parameters at the cutting zone. Finite Element Analysis of the machining simulation process employing user defined input parameters is an effective technique to determine certain output responses, which are otherwise difficult to determine.
Aviation alloys exhibit superior properties such as high-strength-to-weight ratio and corrosion resistance but these alloys possess poor machinability. To overcome this disadvantage, new machining ...methods (Ultrasonic assisted machining, hot machining, etc.) are developed. Hot ultrasonic assisted turning (HUAT) is a new hybrid machining method which changes the cutting system between tool and workpiece, therefore, reduced cutting forces and better surface finish for workpiece are obtained. In this study, 2D finite element (FE) analysis is carried out to investigate the effects of these machining methods on titanium and Hastelloy-X alloys in terms of cutting forces, cutting tool temperatures and effective stresses. DEFORM-2D software is used during analyses. In addition, an experimental study is conducted to verify numerical results. During verification, cutting tool temperature is taken into consideration. It is confirmed that HUAT technique reduces cutting forces and effective stress significantly but cutting temperature increases compared to conventional and ultrasonic assisted turning.
The hot weld metal grinding of the cylindrical parts with soft and medium-soft wheels is investigated. Work-time wheel wear charts and grinding cutting force diagrams received through the test and ...calculation data are offered. Applicable equations for the cutting forces occurring in the wheel — workpiece interaction, depending on the grinding conditions through the hot weld metal grinding of the barrels with the soft and medium-soft wheels at the welding arc burn-out and cutter withdrawal moment, are developed.
•Tool life can be multiplied by 9 using the high-pressure water-jet assistance.•Productivity can be increased by approximately 30% at the pressure of 100bar.•The increase of the cutting speed reduces ...the effectiveness of the water jet assistance.
This paper presents experimental results concerning the machinability of the titanium alloy Ti17 with and without high-pressure water jet assistance (HPWJA) using uncoated WC/Co tools. For this purpose, the influence of the cutting speed and the water jet pressure on the evolution of tool wear and cutting forces have been investigated. The cutting speed has been varied between 50m/min and 100m/min and the water jet pressure has been varied from 50bar to 250bar. The optimum water jet pressure has been determined, leading to an increase in tool life of approximately 9 times. Compared to conventional lubrication, an increase of about 30% in productivity can be obtained.
Cubic Nitride Boron (CBN) tools are generally used for machining harder alloys such as hardened high Cr steels, titanium and nickel alloys. The tools are expected to withstand the heat and pressure ...developed when machining at higher cutting conditions because of their high hardness and melting point. This paper evaluates the performance of different CBN tool grades in finish turning Ti–6Al–4V (IMI 318) alloy at high cutting conditions, up to 250
m
min
−1, with various coolant supplies. Tool wear, failure modes, cutting and feed forces and surface roughness of machined surfaces were monitored and used to access the performance of the cutting tools. Comparative trials were carried out with uncoated carbide tools when machining at a speed of 150
m
min
−1. Test results show that the performance of CBN tools, in terms of tool life, at the cutting conditions investigated is poor relative to uncoated carbide tools, as expected and often, reported due probably to rapid notching and excessive chipping of the cutting edge associated with a relatively high diffusion wear rate that tends to weaken the bond strength of the tool substrate. An increase in the CBN content of the cutting tool also led to a reduction in tool life when machining at the cutting conditions investigated.
Alterations in cutting tool surfaces are being looked at as futuristic developments in cutting tool technology. Tool surface texturing by subtractive as well as an additive way can contribute to the ...tool performance and productivity improvement. The tool textures can be in the range of nano to micro-level. They help to reduce friction, manage the heat-induced during machining and facilitate chip removal. For textured surfaces, small cavities or dimples uniformly distributed over the sliding surface have been found to have the best tribological effect. In this study, two different micro-texture patterns i.e., micro-dimple and micro-channel were made on the rake-face close to the main cutting edge of the carbide tool insert. Ultra-short pulsed (nanosecond) fiber laser has been used for texturing. An array of texture patterns with 80 µm width/diameter and 70 µm depth has been engraved on the uncoated tungsten carbide tool. The textured inserts have been used for machining trials at 30 m/min to 100 m/min for Inconel 718 to compare the relative performance of the textures in terms of three components of cutting force and machined surface roughness. The experimental observations showed higher components of cutting force for channel textured tools in comparison to dimple textured tools. However, a better surface finish has been observed with channel textured tools. Cutting forces has been observed varying significantly with cutting speed in the case of dimple textured tools. Radial forces were observed higher in magnitude followed by tangential cutting force and feed force for both the textured tools. This study suggests having further studies considering the effect of different texture patterns on the cutting forces, surface roughness, and tool life while turning Inconel 718.
Cutting forces continues to be a major limitation in machining operations. In order to avoid high cutting forces, low feed-rate or low axial/radial can be utilized which decrease the productivity. ...Special end mills such as serrated or crest-cut milling tools can be used in roughing operations to decrease the cutting forces and increase the productivity. In this work, mechanics of serrated end mills are modeled. Moreover, effects of serration shapes on the mechanics of milling are investigated and methods for designing optimum serration shapes are presented. Proposed model predictions are verified through experiments.
The selection of process parameters during hard turning is critical deciding the performance of hard turning. In this research work, an attempt has been made to analyze the influence of tool nose ...radius and workpiece hardness on cutting force and chip-tool interface temperature during hard turning of AISI 4340 steel. The experiments were performed as per layout design with the central composite design. The mathematical models of cutting force and chiptool interface temperature were developed using second order regression analysis. The adequacies of the developed models are analyzed by performing confirmation runs. The significance of the models and influence of the process parameters have been carried out based on Analysis of Variance (ANOVA) technique. The optimal values of the process parameters which provide maximum machining performance are predicted. The results show that workpiece hardness is the significant parameter which affects the performance of hard turning.
PDF
