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CUTTING TOOLS
Grade upgrade Building a house begins with laying the foundation. The strength and the reliability of the whole house depends on how strong the foundation is. In cutting tool engineering, this foundation is a cutting material. There are various types of cutting materials: cemented carbide, polycrystalline diamond, high-speed steel, ceramics and so on, and each type contains different grades. At various stages in the history of metal cutting, the introduction of each new cutting material and its use have led to a significant change in the level of cutting speeds, and consequently of productivity. However, if the previous century, especially its second half, was marked by the rapid progress of tool materials, today we do not see any significant new solutions in this field. Does this mean that the development of new tool materials has already reached its peak and is experiencing stagnation? Of course not. It is simply that the new developments are deep within the cutting material and are focused on its structure and can be observed only with the help of scanning electron microscopy (SEM), X-ray diffraction (XRD), electron backscatter diffraction (EBCD), and other sophisticated methods. They cover a tremendously complicated world of coatings that is extremely diverse despite its very small thickness, measured only by microns. The most commonly available cutting material today is cemented carbide, primarily coated. In terms of performance, it represents a reasonable balance between efficiency, tool life and cost. Cemented carbide is known also as ‘hard metal’, ‘tungsten carbide’ or simply ‘carbide’. A combination of cemented carbide, coating, and postcoating treatment produces a carbide grade. Only one of these components – the cemented carbide – is an essential element in the grade. The others are optional. Cemented carbide is a composite material comprising hard carbide particles that are cemented together by binding metal (mainly cobalt). Most cemented carbides used for producing cutting tools integrate wear-resistant coatings. There are also various treatment processes that are applied to already coated cemented carbide – for example, the rake surface of an indexable insert. New developments in cemented carbide, as a tool material, are concentrated in three directions: carbide production technologies, advanced coating
methods, and innovative post-coating techniques. Considerable success has been achieved in each of these directions; this is reflected in the wealth of new products introduced to the market by leading cutting tool manufacturers. Cutting tool customers might analyse the grades using parameters such as productivity, tool life, and performance. Indeed, the question of how a new product was created to meet customer requirements fades into the background as applicability and efficiency form the main measure of progress from the customer’s point of view. In upgrading carbide grades, Iscar is very sensitive to a challenge faced by the metalworking industries. In this context, Iscar’s tool material solutions, which are developed considering the trends of modern metalworking, can be quite indicative. Take, for example, difficult-to-cut materials such as titanium and heat-resistant steels and exotic superalloys. Recently, the share of their application in industry has increased significantly. Along with the aircraft industry, a traditional consumer of these materials, they may be increasingly found in power engineering, automotive and oil & gas branches. The growing usage of the materials demands technological solutions, including machinery and cutting tools. The new tools require an appropriate foundation, made of advanced cutting tool materials, to achieve the desired cutting geometry. And for the construction of this foundation, Iscar offers its new effective ‘bricks’ – upgraded carbide grades developed by company metallurgists in the last few years. In milling, Iscar has developed PVD (physical vapour deposition)coated IC882 and CVD (chemical vapour deposition)-coated IC5820 grades– two chocolate-colour carbide grades for cutting titanium, high-temperature alloys, and stainless steel. An integral component of the grades is a post-coating treatment that facilitates longer tool life, due to increased resistance to chipping, notch wear, and build-up edge formation. The IC882 grade demonstrates impressive performance when machining conditions are hard, and Insert production starts with carbide powder.
AMT OCT/NOV 2020
