Papers by Keyword: Crater Wear

Abstract: Enhanced tool life of cutting inserts are most suitable condition for higher productivity of a manufacturing industry. Several methods are found and employed for higher tool life of cutting inserts among which cryogenic treatment is considered as the most significant method but no adequate researches have been found concerning the impact of cryogenic treatment on cermet inserts especially in hard turning operation. Hence, in the current experimental investigation, the comparative assessment of various responses such as flank wear, crater wear, chip morphology, and chip compression ratio were carried out during machining of hardened steel with both untreated and cryo-treated cermet inserts under dry cutting condition. Wear on the rake faces and flank faces were studied using advanced optical microscope, while chip morphology was studied using SEM. The experimental result demonstrated that the uncoated deep cryotreated with tempered cermet insert delivered better results in comparison to other cermet inserts. Deep cryogenically treated with tempered insert was found to be more suitable during machining of hardened steel because of the enhancement of wear resistance, micro hardness and toughness.

Abstract: Titanium alloys are referred to difficult-to-cut materials because of its some inferior properties like low thermal conductivity and high chemical reactivity. To improve machinability of these alloys one way is to use cutting fluids which removes the heat generated at the chip tool interface during the machining process. But coolant with low pressure and improper delivery is not able to break the vapor barrier created by high cutting temperature. The present work investigates the effect of using high pressure coolant system (50 Bar) on machinability of Ti6Al4V. The machinability was measured in terms of tool wear. The dominant tool wear mechanism was investigated by using scanning electron microscopy and energy dispersive X-ray analysis of worn out cutting tool surfaces. Abrasion wear on flank face and crater wear on the rake face was observed as a dominant tool wear mechanism. Along with this diffusion of titanium from the work surface to tool face is also confirmed.

Abstract: Recently, in order to make positively use of the effect of adhesive layer, which works as Build-up edge or Belag on the tool surface during machining operation, there have many investigations on the technique to reduce the wear of cutting tool. However, the mechanism of wear on the rake face is unknown and the reason why the adhesive layer can resist the abrasion is also unclear.This study aims to propose a new crater high-cycle fatigue wear model depending on the tool adhesion model established by the surface cluster on the interface between the Tool-Work Piece. By using this model we can elucidate the mechanism of adhesive layer. When the chip flows on the rake face, the commensurate phase occurs in the surface cluster on the interface, and the surface cluster slides in the similar form of dislocation. At the same time, the strong chemical bonding among the surface clusters becomes the repeat force which can result in the fatigue failure on the tool, and the tool crater wear happens. The energy dissipation process associates with the vibration of cluster, which increases the tool temperature rapidly. Therefore, the crater wear is a damage process on the tool with the high-temperature and high-cycle fatigue.In this study, the mechanism of crater wear when the cemented carbide cut the carbon steel was investigated using the adhesion cluster model, and the crater wear model was proposed to estimate the properties of the adhesive layer.

Abstract: This paper presents a method of measuring the volumetric tool wear by use of the image processing technique. A single CCD camera based stereo vision system is built to acquire the image pair. The crater wear’s boundary of the cutting tool is then detected, and then the 3D volumetric shape of the worn region on the rake face is reconstructed through the developed image matching algorithms, and the crater’s volume and depth is estimated. A Matlab software system is developed to perform image acquisition, calibration, image rectification, image adjustment, stereo matching, crater’s depth estimation, and the representation of the volumetric tool wear. The feasibility of the proposed method is verified through experiments.

Abstract: Ultrasonic assisted drilling has made remarkable achievements in recent years. Improvements in many fields have been considered by researchers and a way forward lies in applying the results in industries. In this recent experimental study, the effect of ultrasonic assisted drilling was reviewed. The material was high-alloyed steel X20Cr13 and for more accurate comparison between drilling with or without vibration, ordinary HSS tools were used and the vibrations were imposed to the workpiece. Also, the test structure was designed using numerical calculations and FEM method. The critical criterion was to have vibration in longitudinal mode and in the direction of the tool feed, reaching a peak at the cutting point. The results have shown significant changes in chip characteristics and tool life subsequently. The length of chip decreased and this improvement automatically leads to many other progresses in the procedure amongst which there is an extended tool life. The other progresses were higher surface quality, less burrs on edge of the holes and less drilling force which are not in the scope of this paper.

Abstract: In this study, flank wear on CBN and PCBN tools due to cutting forces were studied. Turning tests were carried using cutting speeds of 100, 125, 150, 175 and 200 m/min with feed rates of 0.10, 0.20 and 0.30 mm/rev and constant depth of cut. The performances of tools were evaluated based on the flank wear and cutting forces. There is clear relationship between flank wear and cutting forces while turning hard martensitic stainless steel by CBN and PCBN tools. Low cutting forces leads to low flank wear formation and low cutting forces provided good dimensional accuracy of the work material including low surface roughness. Flank wear formation was mostly caused by abrasion and adhesion. The built up edges formed reduced the cutting forces and also causes the heat generated at tool tip and work interface. High cutting forces are identified and this may be due to heat and flank wear combinations. Flank and crater wear on the rake face and hard metal deposition due to diffusion of metals on the cutting tool surface are the damages occurred during process.

Abstract: Wear modeling makes it possible to predict the evolution of wear profile and explain wear mechanism from process variables, such as temperature, pressure and sliding velocity etc. A composite crater wear model considering adhesive and diffusion wear is established by means of experiment and modeling in conventional speed machining. A series of cutting tests are performed to obtain wear profiles and corresponding process variables. The constants in wear model are fitted by regression analysis with crater wear tests. This crater wear model shows a good predictive capability in conventional cutting speed.