The paper presents the results of the investigation into the formation of the nanolayer structure of the Ti-TiN-(Ti,Cr,Al)N coating and its influence on the thickness of coatings, their resistance to ...fracture in scratch testing, and the wear resistance of coated tools in turning 1045 steel. The structure of the coatings with the nanolayer thicknesses of 302, 160, 70, 53, 38, 24, 16, and 10 nm was studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution (HR) TEM. It is shown that the grain sizes in the nanolayers decrease to certain values with an increase in the thickness of the nanolayers, and then, with a further decrease in the nanolayer thickness, the grain sizes of the nanolayer grow as the interlayer interfaces cease to produce a restraining effect on the growth of the grains. The study found that the nanolayer thickness influenced the wear of carbide cutting tools and the pattern of fracture for the Ti-TiN-(Ti,Cr,Al)N coatings.
•As the thickness of the nanolayers decreases, the AlN phase content decreases significantly.•Internanolayer interfaces restrain grain growth only when the thickness of nanolayers is sufficiently large.•With a decrease in the nanolayer thickness, the hardness of the coating first decreases, and then begins to grow.•For a coating with a small thickness of nanolayers, brittle fracture more often occurs.•The longest tool life was shown by coating nanolayers equal to 16 and 24 nm.
A variety of cutting tool materials are used for the contact mode mechanical machining of components under extreme conditions of stress, temperature and/or corrosion, including operations such as ...drilling, milling turning and so on. These demanding conditions impose a seriously high strain rate (an order of magnitude higher than forming), and this limits the useful life of cutting tools, especially single-point cutting tools. Tungsten carbide is the most popularly used cutting tool material, and unfortunately its main ingredients of W and Co are at high risk in terms of material supply and are listed among critical raw materials (CRMs) for EU, for which sustainable use should be addressed. This paper highlights the evolution and the trend of use of CRMs) in cutting tools for mechanical machining through a timely review. The focus of this review and its motivation was driven by the four following themes: (i) the discussion of newly emerging hybrid machining processes offering performance enhancements and longevity in terms of tool life (laser and cryogenic incorporation); (ii) the development and synthesis of new CRM substitutes to minimise the use of tungsten; (iii) the improvement of the recycling of worn tools; and (iv) the accelerated use of modelling and simulation to design long-lasting tools in the Industry-4.0 framework, circular economy and cyber secure manufacturing. It may be noted that the scope of this paper is not to represent a completely exhaustive document concerning cutting tools for mechanical processing, but to raise awareness and pave the way for innovative thinking on the use of critical materials in mechanical processing tools with the aim of developing smart, timely control strategies and mitigation measures to suppress the use of CRMs.
The paper presents the influence of the cutting zone cooling method on the wear of a cutting tool made of sintered carbide P25 during the process of turning AISI 1045 steel. The following cooling ...variants have been considered: dry machining, MQCL method and MQCL+EP/AW. The tests have been performed with different cutting speeds. This work also emphasizes the influence of the cutting tool wear on the chip shape and the indices of the chip formation zone: the chip thickening coefficient and the friction coefficient on the rake face. It has been found that during MQCL+EP/AW cooling, the tool wear decreases by 20% at the lowest cutting speed to 51% at the highest cutting speeds as compared to dry machining. Application of the EP/AW additive also results in a reduction of the friction coefficient on the rake face. In consequence it advantageously influences the chip shape. In a scanning analysis of the tool point, it has been found that a thin layer of a tribofilm is formed on the wedge surfaces, which results in an improvement of the machining process conditions.
Display omitted
Inconel 718 is the most popular nickel-based superalloy, extensively used in aerospace, automotive and energy industries owing to its extraordinary thermomechanical properties. It is ...also notoriously a difficult-to-cut material, due to its short tool life and low productivity in machining operations. Despite significant progress in cutting tool technologies, the machining of Inconel 718 is still considered a grand challenge.
This paper provides a comprehensive review of recent advances in machining Inconel 718. The progress in cutting tools’ materials, coatings, geometries and surface texturing for machining Inconel 718 is reviewed. The investigation is focused on the most adopted tool materials for machining of Inconel 718, namely Cubic Boron Nitrides (CBNs), ceramics and coated carbides. The thermal conductivity of cutting tool materials has been identified as a major parameter of interest. Process control, based on sensor data for monitoring the machining of Inconel 718 alloy and detecting surface anomalies and tool wear are reviewed and discussed. This has been identified as the major step towards realising real-time control for machining safety critical Inconel 718 components. Recent advances in various processes, e.g. turning, milling and drilling for machining Inconel 718 are investigated and discussed. Recent studies related to machining additively manufactured Inconel 718 are also discussed and compared with the wrought alloy. Finally, the state of current research is established, and future research directions proposed.
Nitrogen plays a key role in tailoring the surface structures in WC–Co–Cubic graded cemented carbides. In this study, graded cemented carbides were sintered at 1450 °C for 2 h in a N-free atmosphere ...using TiN, ZrN, and HfN as multiple N sources. The elemental and compositional distributions of the resultant cemented carbides were measured to determine the microstructural evolution in the graded surface layer. For alloys incorporated with different N sources, two key characteristics, the residual cubic phase and thickness of the graded layer, were investigated. It was revealed that the thermodynamic formation energies of the cubic nitrides was the main factor to the microstructural evolution. In addition, the hardness distributions in the graded layers were measured using micro-indentation tests. Overall, a relationship between microstructure and hardness was established from the surface to the core of the investigated materials.
•Cutting tools having textured surfaces are developed for improving their crater and flank wear resistance.•The developed tools show excellent wear resistances in cutting of medium carbon steels.•A ...mechanism for suppressing the wear on the textured tool surface is discussed.•Wear resistances of the developed tools have a strong correlation with geometries of the texture.•Optimal texture dimension differs depending on cutting conditions.
We have proposed cutting tools with various textured surfaces to increase cutting tool life. Our previous studies have developed cutting tools having periodical stripe-grooved surfaces on their rake face formed using femtosecond laser technology, which displayed high crater wear resistance in cutting of steel materials. In this study, the mechanism for suppressing the crater wear on the tool surface and the relationship between texture dimensions and wear resistance were investigated to provide a guideline for developing tools with textured surfaces. Furthermore, we newly introduced the textured surfaces into a flank face of cutting tools to improve flank wear resistance. Face milling experiments on steel materials exhibited that the newly developed tool having the textured flank face significantly reduced the flank wear. Moreover, the influences of texture dimensions and cutting conditions on the flank wear resistance were also discussed.
The machining performance and mechanisms of straight-nosed cutting tools in the single-point diamond turning (SPDT) of curved Zerodur optics are analysed and experimentally investigated. Analyses ...into the SPDT processes of convex spherical Zerodur samples have shown that using straight-nosed cutting tools can significantly reduce the cut thickness for facilitating the ductile-mode material removal while increasing the width of cut compared with the conventional round-nosed cutting tools. Calculations have also shown that lower cutting force intensities would be acting on the straight cutting edges than the round ones, which can in turn contribute to decreasing the heat flux density into the cutting tool, and is thus expected to reduce the thermal-induced cutting tool wear. To verify these, SPDT tests of spherical Zerodur samples were carried out, where a reduction of the machined surface roughness from Ra 173 nm to 15 nm was achieved by using the straight-nosed cutting tools, and a 96% area ratio of ductile-mode cutting was obtainable with very slight damage marks left on the machined surface. It has been further found that the straight-nosed cutting tools suffered less flank wear, as well as less bluntness and recession of the cutting edge. The mean cutting and thrust forces acting on per unit length of the cutting edge were found to be reduced, which agrees well with the prior analytical results, and is believed as evidence for the reduction of cutting power required for each unit cutting edge area for enhancing the resistance to cutting tool wear.
Display omitted
●This work reports the mechanisms behind which using straight-nosed cutting tools improves the machining performance in single-point diamond turning of curved Zerodur optics.●A 96% area ratio of ductile-mode cutting is obtainable in single-point diamond turning of spherical Zerodur samples by using straight-nosed cutting tools for a nano-scale surface finish.●Using the straight-nosed cutting tools is effective in reducing the recession and bluntness of tool cutting edge, as well as work adhesion and flank wear for extending the cutting tool life.●The straight-shaped cutting edge reduces the cutting force intensities applied on the cutting edge and heat flux density into the cutting tool for the reduction of cutting tool wear.
Cutting is defined as the process of creating an opening or a wound on a surface, particularly using a sharp tool. The process is used to promote the development including in the fields of ...agricultural, geological, mechanical, forestry, and medical engineering. However, cutting frequently suffers from low efficiency, poor quality, and high energy consumption because of adhesion, abrasion, or friction occurring on the surface of the cutting tool. To solve these problems, bionics has been introduced into the design of tools by several scholars. However, a comprehensive review of the bionic design of cutting tools is not yet available. To address this gap, a literature survey of bionic applications in cutting tool design is conducted in this study. To explain the mechanisms of different bionic tools systematically, the review is conducted from the perspective of cutting materials in different engineering fields because of their different mechanisms of adhesion, abrasion, or friction. Four types of bionic cutting tools are summarized and analyzed based on existing literature: soil, rock, metal, and biological tissue cutting tools. Future development trends of bionic tools from the perspectives of their bionic mechanism and applications are discussed based on literature analysis and bionic investigations. It is expected that new inspirations will be drawn by researchers and the development of bionic cutting tools will be promoted based on this study.
•Studies about bionic cutting tools are reviewed.•Bionic cutting tools from multiple engineering are summarized and analyzed.•Bionic mechanisms to inhibit cutting tools' adhesion, abrasion or friction are shown.•Research prospects of bionic cutting tools are proposed.
PDF
