Seminar 1 m.tech final
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emerging cutting tool materials
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Seminar 1 m.tech final
- 1. Emerging Cutting Tool Materials for Improving Performance of Machining DEPARTMENT OF MECHANICAL ENGINEERING HALDIA INSTITUTE OF TECHNOLOGY,HALDIA PURBA MEDINIPUR-721657,WEST BENGAL 2016-2017 HALDIA INSTITUTE OF technology Submitted by. SUJAY KUMAR PATAR Registration no.161030410026 of 2016- 17 Roll no.10312416004 M.Tech ME sem-1
- 2. What Do We Use To Cut A Apple ?
- 3. Which Tool ?
- 4. Knife is Harder_(material property) Knife is Sharper_(design) It is used to cut, with ease i.e. Approach Angle_(technique or Mechanism)
- 5. What Do We Use To Cut Steel or Cast Iron or Stainless Steel? Tungsten Carbide – Since it’s harder than most of the materials. Diamond is hardest than all other materials
- 6. Introduction Machining is accomplished by cutting tools. Cutting tools undergo high force and temperature and temperature gradient. Tool life Two aspects of design 1) Tool Materials 2)Tool Geometry Cutting fluids
- 7. Machining is the process of removing unwanted materials from work piece. The major drawback of this process is loss of material in the form of chips. Material removal process Conventional Cutting Axisymmetri c cutting Pismatic cutting Abrasive Bonded cutting Loose cutting Un-conventional CHEMICAL AND ELECTRO- CHEMICAL ENERGY BASED PROCESSES THERMAL ENERGY BASED PROCESSES ELECTRICAL ENERGY BASED PROCESSES MECHANICAL ENERGY BASED PROCESSES Turning* Drilling* Boring Milling* Sawing Shaping Grinding* Honing Super finishing Lapping
- 8. Tool as index of progress of civilization Rough estimation of time(in year) Cultural stages Types of tools 1,000,000 800,000 100,000 50,000 8,000 B.C 5,500 B.C 3,000 B.C 1,400 B.C Pre-Palaeolkthic Lower-Palaeolithic Middle –Paleolithic Upper Palaeoithic Mesolithic Neolithic Bronze Age Iron Age Stones Stones with chopping tools Transinding bending of ancient tool types Bades,files fine flakes Agricultural implementations & animal domestication Use of bronze elements Uses of metal and beginning of modern cutting tools. Increase in productivity(MRR) with progress of
- 9. What is Common in this Process? Turning Milling Drilling Grinding
- 10. Cutting tool considerations… Tool life Three modes of failure Premature Failure Fracture failure -Cutting force becomes excessive and/or dynamic, leading to brittle fracture Thermal failure -Cutting temperature is too high for the tool material Gradual Wear Gradual failure. Tool wear: Gradual failure Flank wear -flank (side of tool) Crater wear -top rake face Notch wear Nose radius wear
- 11. Manufacturing Technology Machining requirements The blank and the cutting tool are properly mounted (in fixtures) and moved in a powerful device called machine tool enabling gradual removal of layer of material from the work surface resulting in its desired dimensions and surface finish. Additionally some environment called cutting fluid is generally used to ease machining by cooling and lubrication.
- 12. The Balance of Properties of cutting tool Hot hardness of the different commonly used tool materials
- 13. Silent properties of cutting tool materials Hot hardness Toughness and strength Wear resistance Thermal conductivity Low coefficient of thermal expansion Weldability
- 14. 1)Carbon Steels It is the oldest of tool material. The carbon content is 0.6~1.5% with small quantities of silicon, chromium, manganese, and vanadium to refine grain size. Maximum hardness is about HRC 62. This material has low wear resistance and low hot hardness. The use of these materials now is verylimited.
- 16. 2)Carbide tools
- 18. 4)Coated carbide# Cemented Carbide − are composed primarily of carbon mixed with tungsten, tantalum and titanium powders and bonded by cobalt in a sintering process. − have excellent red hardness capabilities. − can remove large amounts of materials in a short period of time. − are capable of CS 3−4 times greater than HSS cutting tools. Machining by coted carbide inserts
- 19. 5)High performance ceramic (HPC)tools 1)Zerconia toughened alumina 2)Whisker reinforced ceramic 3)Metal toughed alumina. Comparison of important properties of ceramic and tungsten carbide
- 20. 5)Cermet's=cer(ceramic)+met(metal) The favourable cermets include TiC ,TiN,TiCN
- 21. 6)CBN
- 22. Diamond
- 23. Polycrystalline Diamond ( PCD ) unique PCD also suffers from some limitations like : • High tool cost • Presence of binder, cobalt, which reduces wear resistance and thermal stability • Complex tool shapes like in-built chip breaker cannot be made • Size restriction, particularly in making very small diameter tools The above mentioned limitations of polycrystalline diamond tools have been almost overcome by developing Diamond coated tools.
- 24. Diamond coated carbide tools • Free from binder, higher hardness, resistance to heat and wear more than PCD and properties close to natural diamond • Highly pure, dense and free from single crystal cleavage • Permits wider range of size and shape of tools and can be deposited on any shape of the tool including rotary tools • Relatively less expensive
- 25. Future Possibilities From the above discussion it is evident that continuous interest is there for developing new cutting tool materials to meet the challenge of aerospace age. The following ideas appear t have some relevance to possible new material concepts: 1.Thermo mechanical treatments 2.Industry point of view cost and time benefits. 2.Internal oxidations to produce small (10 nm) hard particle 3.Multi phase material with each phase interconnected produced. 4.Directional solidification of cast tool materials ,and casting technique. 5.Continues and extended application of the composite concept - It is seen that there are many existing new possibilities for future improvement of cutting tool material capability.
- 26. THANK YOU
Editor's Notes
- Speech contained: Goobd morning respected professors, today my deminar topic on Emerging Cutting Tool Materials for Improving Performance of Machining .here
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- Speech contained: The cutting tool materials must possess a number of important properties to avoid excessive wear, fracture failure and high temperatures in cutting, The following characteristics are essential for cutting materials to withstand the heavy conditions of the cutting process and to produce high quality and economical parts: v hardness at elevated temperatures (so-called hot hardness) so that hardness and strength of the tool edge are maintained in high cutting temperatures: v toughness: ability of the material to absorb energy without failing. Cutting if often accompanied by impact forces especially if cutting is interrupted, and cutting tool may fail very soon if it is not strong enough. v wear resistance: although there is a strong correlation between hot hardness and wear resistance, later depends on more than just hot hardness. Other important characteristics include surface finish on the tool, chemical inertness of the tool material with respect to the work material, and thermal conductivity of the tool material, which affects the maximum value of the cutting temperature at tool-chip interface.
- HSS tools are so named because they were developed to cut at higher speeds. Developed around 1900 HSS are the most highly alloyed tool steels. The tungsten (T series) were developed first and typically contain 12 - 18% tungsten, plus about 4% chromium and 1 - 5% vanadium. Most grades contain about 0.5% molybdenum and most grades contain 4 - 12% cobalt. It was soon discovered that molybdenum (smaller proportions)could be substituted for most of the tungsten resulting in a more economical formulation which had better abrasion resistance than the T series and undergoes less distortion during heat treatment. Consequently about 95% of all HSS tools are made from M series grades. These contain 5 - 10% molybdenum, 1.5 - 10% tungsten, 1 - 4% vanadium, 4% Chromium and many grades contain 5 - 10% cobalt. HSS tools are tough and suitable for interrupted cutting and are used to manufacture tools of complex shape such as drills, reamers, taps, dies and gear cutters. Tools may also be coated to improve wear resistance. HSS accounts for the largest tonnage of tool materials currently used. Typical cutting speeds: 10 - 60 m/min.
- Speech contained: Also known as cemented carbides or sintered carbides were introduced in the 1930s and have high hardness over a wide range of temperatures, high thermal conductivity, high Young's modulus making them effective tool and die materials for a range of applications. The two groups used for machining are tungsten carbide and titanium carbide, both types may be coated or uncoated. Tungsten carbide particles (1 to 5 micro-m) are are bonded together in a cobalt matrix using powder metallurgy. The powder is pressed and sintered to the required insert shape. titanium and niobium carbides may also be included to impart special properties. A wide range of grades are available for different applications. Sintered carbide tips are the dominant type of material used in metal cutting. The proportion of cobalt (the usual matrix material) present has a significant effect on the properties of carbide tools. 3 - 6% matrix of cobalt gives greater hardness while 6 - 15% matrix of cobalt gives a greater toughness while decreasing the hardness, wear resistance and strength. Tungsten carbide tools are commonly used for machining steels, cast irons and abrasive non-ferrous materials. Titanium carbide has a higher wear resistance than tungsten but is not as tough. With a nickel-molybdenum alloy as the matrix, TiC is suitable for machining at higher speeds than those which can be used for tungsten carbide. Typical cutting speeds are: 30 - 150 m/min or 100 - 250 when coated.
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- Speech contained: The properties and performance of carbide tools could be substantially improved by • Refining microstructure • Manufacturing by casting – expensive and uncommon • Surface coating – made remarkable contribution. Thin but hard coating of single or multilayers of more stable and heat and wear resistive materials like TiC, TiCN, TiOCN, TiN, Al2O3 etc on the tough carbide inserts (substrate) by processes like chemical Vapour Deposition (CVD), Physical Vapour Deposition (PVD) etc at controlled pressure and temperature enhanced MRR and overall machining economy remarkably enabling, • reduction of cutting forces and power consumption • increase in tool life (by 200 to 500%) for same VC or increase in VC (by 50 to 150%) for same tool life • improvement in product quality • effective and efficient machining of wide range of work materials • pollution control by less or no use of cutting fluid through • reduction of abrasion, adhesion and diffusion wear • reduction of friction and BUE formation • heat resistance and reduction of thermal cracking and plastic deformation
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- Introduced in the early 1960s, this is the second hardest material available after diamond. cBN tools may be used either in the form of small solid tips or or as a 0.5 to 1 mm thick layer of of polycrystalline boron nitride sintered onto a carbide substrate under pressure. In the latter case the carbide provides shock resistance and the cBN layer provides very high wear resistance and cutting edge strength. Cubic boron nitride is the standard choice for machining alloy and tool steels with a hardness of 50 Rc or higher. Typical cutting speeds: 30 - 310 m/min.
- Speech contained: Single stone, natural or synthetic, diamond crystals are used as tips/edge of cutting tools. Owing to the extreme hardness and sharp edges, natural single crytal is used for many applications, particularly where high accuracy and precision are required. Their important uses are : • Single point cutting tool tips and small drills for high speed machining of non-ferrous metals, ceramics, plastics, composites, etc. and effective machining of difficult-to-machine materials • Drill bits for mining, oil exploration, etc. • Tool for cutting and drilling in glasses, stones, ceramics, FRPs etc. • Wire drawing and extrusion dies • Superabrasive wheels for critical grinding. Limited supply, increasing demand, high cost and easy cleavage of natural diamond demanded a more reliable source of diamond. It led to the invention and manufacture of artificial diamond grits by ultra-high temperature and pressure synthesis process, which enables large scale manufacture of diamond with some control over size, shape and friability of the diamond grits as desired for various applications.
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- Speech contained: Since the invention of low pressure synthesis of diamond from gaseous phase, continuous effort has been made to use thin film diamond in cutting tool field. These are normally used as thin (<50 μm) or thick (> 200 μm) films of diamond synthesised by CVD method for cutting tools, dies, wear surfaces and even abrasives for Abrasive Jet Machining (AJM) and grinding. Thin film is directly deposited on the tool surface. Thick film ( > 500 μm) is grown on an easy substrate and later brazed to the actual tool substrate and the primary substrate is removed by dissolving it or by other means. Thick film diamond finds application in making inserts, drills, reamers, end mills, routers. CVD coating has been more popular than single diamond crystal and PCD mainly above 4 points While cBN tools are feasible and viable for high speed machining of hard and strong steels and similar materials, Diamond tools are extremely useful for machining stones, slates, glass, ceramics, composites, FRPs and non ferrous metals specially which are sticky and BUE former such as pure aluminum and its alloys. CBN and Diamond tools are also essentially used for ultraprecision as well as micro and nano machining
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